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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not give a
31            partial match for the string "\r".
32    
33    
34    Version 8.30 04-February-2012
35    -----------------------------
36    
37    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
38        name is defined in ctype.h.
39    
40    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
41        only in quite long subpatterns.
42    
43    3.  Removed the function pcre_info(), which has been obsolete and deprecated
44        since it was replaced by pcre_fullinfo() in February 2000.
45    
46    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
47        match a (*MARK), and the match failed at the start of the subject, a
48        reference to memory before the start of the subject could occur. This bug
49        was introduced by fix 17 of release 8.21.
50    
51    5.  A reference to an unset group with zero minimum repetition was giving
52        totally wrong answers (in non-JavaScript-compatibility mode). For example,
53        /(another)?(\1?)test/ matched against "hello world test". This bug was
54        introduced in release 8.13.
55    
56    6.  Add support for 16-bit character strings (a large amount of work involving
57        many changes and refactorings).
58    
59    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
60        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
61        from a file.
62    
63    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
64        rounding is not applied in this particular case).
65    
66    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
67        if they appear, or are escaped, in patterns.
68    
69    10. Get rid of a number of -Wunused-but-set-variable warnings.
70    
71    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
72        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
73        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
74        also returns the mark "x". This bug applied to capturing parentheses,
75        non-capturing parentheses, and atomic parentheses. It also applied to some
76        assertions.
77    
78    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
79        information out of configure.ac instead of relying on pcre.h.generic, which
80        is not stored in the repository.
81    
82    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
83        -lreadline.
84    
85    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
86    
87    15. Applied Graycode's patch to put the top-level frame on the stack rather
88        than the heap when not using the stack for recursion. This gives a
89        performance improvement in many cases when recursion is not deep.
90    
91    16. Experimental code added to "pcretest -C" to output the stack frame size.
92    
93    
94    Version 8.21 12-Dec-2011
95    ------------------------
96    
97    1.  Updating the JIT compiler.
98    
99    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
100        are added as well.
101    
102    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
103        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
104        calling _pcre_jit_exec. Some extra comments are added.
105    
106    4.  (*MARK) settings inside atomic groups that do not contain any capturing
107        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
108        was introduced by change 18 for 8.20.
109    
110    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
111        ECMA-262 standard.
112    
113    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
114        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
115        This bug was probably introduced by change 9 of 8.13.
116    
117    7.  While fixing 6 above, I noticed that a number of other items were being
118        incorrectly rejected as "not fixed length". This arose partly because newer
119        opcodes had not been added to the fixed-length checking code. I have (a)
120        corrected the bug and added tests for these items, and (b) arranged for an
121        error to occur if an unknown opcode is encountered while checking for fixed
122        length instead of just assuming "not fixed length". The items that were
123        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
124        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
125        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
126    
127    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
128        being incorrectly compiled and would have given unpredicatble results.
129    
130    9.  A possessively repeated subpattern with minimum repeat count greater than
131        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
132        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
133        the first (A) could occur when it should not.
134    
135    10. Add a cast and remove a redundant test from the code.
136    
137    11. JIT should use pcre_malloc/pcre_free for allocation.
138    
139    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
140        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
141        is anything other than /usr, -L is still shown).
142    
143    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
144    
145    14. Perl does not support \N without a following name in a [] class; PCRE now
146        also gives an error.
147    
148    15. If a forward reference was repeated with an upper limit of around 2000,
149        it caused the error "internal error: overran compiling workspace". The
150        maximum number of forward references (including repeats) was limited by the
151        internal workspace, and dependent on the LINK_SIZE. The code has been
152        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
153        the default depends on LINK_SIZE. There is a new upper limit (for safety)
154        of around 200,000 forward references. While doing this, I also speeded up
155        the filling in of repeated forward references.
156    
157    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
158        incorrectly expecting the subject to contain another "a" after the start.
159    
160    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
161        in the match, the SKIP should be ignored. This was not happening; instead
162        the SKIP was being treated as NOMATCH. For patterns such as
163        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
164        tested.
165    
166    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
167        now much more compatible with Perl, in particular in cases where the result
168        is a non-match for a non-anchored pattern. For example, if
169        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
170        "m", where previously it did not return a name. A side effect of this
171        change is that for partial matches, the last encountered mark name is
172        returned, as for non matches. A number of tests that were previously not
173        Perl-compatible have been moved into the Perl-compatible test files. The
174        refactoring has had the pleasing side effect of removing one argument from
175        the match() function, thus reducing its stack requirements.
176    
177    19. If the /S+ option was used in pcretest to study a pattern using JIT,
178        subsequent uses of /S (without +) incorrectly behaved like /S+.
179    
180    21. Retrieve executable code size support for the JIT compiler and fixing
181        some warnings.
182    
183    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
184        not work when the shorter character appeared right at the end of the
185        subject string.
186    
187    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
188        systems.
189    
190    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
191        output it when the /M option is used in pcretest.
192    
193    25. The CheckMan script was not being included in the distribution. Also, added
194        an explicit "perl" to run Perl scripts from the PrepareRelease script
195        because this is reportedly needed in Windows.
196    
197    26. If study data was being save in a file and studying had not found a set of
198        "starts with" bytes for the pattern, the data written to the file (though
199        never used) was taken from uninitialized memory and so caused valgrind to
200        complain.
201    
202    27. Updated RunTest.bat as provided by Sheri Pierce.
203    
204    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
205    
206    29. Computation of memory usage for the table of capturing group names was
207        giving an unnecessarily large value.
208    
209    
210    Version 8.20 21-Oct-2011
211    ------------------------
212    
213    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
214        a POSIX class. After further experiments with Perl, which convinced me that
215        Perl has bugs and confusions, a closing square bracket is no longer allowed
216        in a POSIX name. This bug also affected patterns with classes that started
217        with full stops.
218    
219    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
220        captured substring, but while checking the failing first alternative,
221        substring 1 is temporarily captured. If the output vector supplied to
222        pcre_exec() was not big enough for this capture, the yield of the function
223        was still zero ("insufficient space for captured substrings"). This cannot
224        be totally fixed without adding another stack variable, which seems a lot
225        of expense for a edge case. However, I have improved the situation in cases
226        such as /(a)(b)x|abc/ matched against "abc", where the return code
227        indicates that fewer than the maximum number of slots in the ovector have
228        been set.
229    
230    3.  Related to (2) above: when there are more back references in a pattern than
231        slots in the output vector, pcre_exec() uses temporary memory during
232        matching, and copies in the captures as far as possible afterwards. It was
233        using the entire output vector, but this conflicts with the specification
234        that only 2/3 is used for passing back captured substrings. Now it uses
235        only the first 2/3, for compatibility. This is, of course, another edge
236        case.
237    
238    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
239        main code base, and can be used by building with --enable-jit. When this is
240        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
241        runtime --no-jit option is given.
242    
243    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
244        ovector, the return from the function was zero, implying that there were
245        other matches that did not fit. The correct "exactly full" value is now
246        returned.
247    
248    6.  If a subpattern that was called recursively or as a subroutine contained
249        (*PRUNE) or any other control that caused it to give a non-standard return,
250        invalid errors such as "Error -26 (nested recursion at the same subject
251        position)" or even infinite loops could occur.
252    
253    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
254        computing the minimum length on reaching *ACCEPT, and so ended up with the
255        wrong value of 1 rather than 0. Further investigation indicates that
256        computing a minimum subject length in the presence of *ACCEPT is difficult
257        (think back references, subroutine calls), and so I have changed the code
258        so that no minimum is registered for a pattern that contains *ACCEPT.
259    
260    8.  If (*THEN) was present in the first (true) branch of a conditional group,
261        it was not handled as intended. [But see 16 below.]
262    
263    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
264        Sheri Pierce.
265    
266    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
267        the first byte in a match must be "a".
268    
269    11. Change 17 for 8.13 increased the recursion depth for patterns like
270        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
271        pattern contains any instances of (*THEN). If it does not, the old
272        optimizations are restored. It would be nice to do this on a per-group
273        basis, but at the moment that is not feasible.
274    
275    12. In some environments, the output of pcretest -C is CRLF terminated. This
276        broke RunTest's code that checks for the link size. A single white space
277        character after the value is now allowed for.
278    
279    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
280        For "fr", it uses the Windows-specific input and output files.
281    
282    14. If (*THEN) appeared in a group that was called recursively or as a
283        subroutine, it did not work as intended. [But see next item.]
284    
285    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
286        pattern fragments (but not containing any | characters). If A and B are
287        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
288        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
289        D. In other words, Perl considers parentheses that do not contain any |
290        characters to be part of a surrounding alternative, whereas PCRE was
291        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
292        differently. PCRE now behaves in the same way as Perl, except in the case
293        of subroutine/recursion calls such as (?1) which have in any case always
294        been different (but PCRE had them first :-).
295    
296    16. Related to 15 above: Perl does not treat the | in a conditional group as
297        creating alternatives. Such a group is treated in the same way as an
298        ordinary group without any | characters when processing (*THEN). PCRE has
299        been changed to match Perl's behaviour.
300    
301    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
302        RunGrepTest script failed.
303    
304    18. Change 22 for version 13 caused atomic groups to use more stack. This is
305        inevitable for groups that contain captures, but it can lead to a lot of
306        stack use in large patterns. The old behaviour has been restored for atomic
307        groups that do not contain any capturing parentheses.
308    
309    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
310        suppress the check for a minimum subject length at run time. (If it was
311        given to pcre_exec() or pcre_dfa_exec() it did work.)
312    
313    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
314        fail to work when decoding hex characters in data strings in EBCDIC
315        environments.
316    
317    21. It appears that in at least one Mac OS environment, the isxdigit() function
318        is implemented as a macro that evaluates to its argument more than once,
319        contravening the C 90 Standard (I haven't checked a later standard). There
320        was an instance in pcretest which caused it to go wrong when processing
321        \x{...} escapes in subject strings. The has been rewritten to avoid using
322        things like p++ in the argument of isxdigit().
323    
324    
325    Version 8.13 16-Aug-2011
326    ------------------------
327    
328    1.  The Unicode data tables have been updated to Unicode 6.0.0.
329    
330    2.  Two minor typos in pcre_internal.h have been fixed.
331    
332    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
333        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
334        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
335    
336    4.  There were a number of related bugs in the code for matching backrefences
337        caselessly in UTF-8 mode when codes for the characters concerned were
338        different numbers of bytes. For example, U+023A and U+2C65 are an upper
339        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
340        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
341        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
342        2-byte code at the end of the subject (it thought there wasn't enough data
343        left).
344    
345    5.  Comprehensive information about what went wrong is now returned by
346        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
347        as the output vector has at least 2 elements. The offset of the start of
348        the failing character and a reason code are placed in the vector.
349    
350    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
351        now returned is for the first byte of the failing character, instead of the
352        last byte inspected. This is an incompatible change, but I hope it is small
353        enough not to be a problem. It makes the returned offset consistent with
354        pcre_exec() and pcre_dfa_exec().
355    
356    7.  pcretest now gives a text phrase as well as the error number when
357        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
358        failure, the offset and reason code are output.
359    
360    8.  When \R was used with a maximizing quantifier it failed to skip backwards
361        over a \r\n pair if the subsequent match failed. Instead, it just skipped
362        back over a single character (\n). This seems wrong (because it treated the
363        two characters as a single entity when going forwards), conflicts with the
364        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
365        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
366        has been changed.
367    
368    9.  Some internal refactoring has changed the processing so that the handling
369        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
370        time (the PCRE_DOTALL option was changed this way some time ago: version
371        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
372        which was always a bit of a fudge. It also means that there is one less
373        argument for the match() function, which reduces its stack requirements
374        slightly. This change also fixes an incompatibility with Perl: the pattern
375        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
376    
377    10. More internal refactoring has drastically reduced the number of recursive
378        calls to match() for possessively repeated groups such as (abc)++ when
379        using pcre_exec().
380    
381    11. While implementing 10, a number of bugs in the handling of groups were
382        discovered and fixed:
383    
384        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
385        (a|)*(?1) gave a compile-time internal error.
386        ((a|)+)+  did not notice that the outer group could match an empty string.
387        (^a|^)+   was not marked as anchored.
388        (.*a|.*)+ was not marked as matching at start or after a newline.
389    
390    12. Yet more internal refactoring has removed another argument from the match()
391        function. Special calls to this function are now indicated by setting a
392        value in a variable in the "match data" data block.
393    
394    13. Be more explicit in pcre_study() instead of relying on "default" for
395        opcodes that mean there is no starting character; this means that when new
396        ones are added and accidentally left out of pcre_study(), testing should
397        pick them up.
398    
399    14. The -s option of pcretest has been documented for ages as being an old
400        synonym of -m (show memory usage). I have changed it to mean "force study
401        for every regex", that is, assume /S for every regex. This is similar to -i
402        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
403        using it. It makes it easier to run collections of tests with and without
404        study enabled, and thereby test pcre_study() more easily. All the standard
405        tests are now run with and without -s (but some patterns can be marked as
406        "never study" - see 20 below).
407    
408    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
409        restoration of the capturing data to the outer values was not happening
410        correctly.
411    
412    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
413        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
414        pattern had matched an empty string, and so incorrectly returned a no
415        match.
416    
417    17. There was optimizing code for the last branch of non-capturing parentheses,
418        and also for the obeyed branch of a conditional subexpression, which used
419        tail recursion to cut down on stack usage. Unfortunately, now that there is
420        the possibility of (*THEN) occurring in these branches, tail recursion is
421        no longer possible because the return has to be checked for (*THEN). These
422        two optimizations have therefore been removed. [But see 8.20/11 above.]
423    
424    18. If a pattern containing \R was studied, it was assumed that \R always
425        matched two bytes, thus causing the minimum subject length to be
426        incorrectly computed because \R can also match just one byte.
427    
428    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
429        was incorrectly computed.
430    
431    20. If /S is present twice on a test pattern in pcretest input, it now
432        *disables* studying, thereby overriding the use of -s on the command line
433        (see 14 above). This is necessary for one or two tests to keep the output
434        identical in both cases.
435    
436    21. When (*ACCEPT) was used in an assertion that matched an empty string and
437        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
438    
439    22. When an atomic group that contained a capturing parenthesis was
440        successfully matched, but the branch in which it appeared failed, the
441        capturing was not being forgotten if a higher numbered group was later
442        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
443        group 1 to "a", when in fact it should be unset. This applied to multi-
444        branched capturing and non-capturing groups, repeated or not, and also to
445        positive assertions (capturing in negative assertions does not happen
446        in PCRE) and also to nested atomic groups.
447    
448    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
449        subject after a captured substring, to make it easier to tell which of a
450        number of identical substrings has been captured.
451    
452    24. The way atomic groups are processed by pcre_exec() has been changed so that
453        if they are repeated, backtracking one repetition now resets captured
454        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
455        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
456        "aaa". Previously, it would have been "a". As part of this code
457        refactoring, the way recursive calls are handled has also been changed.
458    
459    25. If an assertion condition captured any substrings, they were not passed
460        back unless some other capturing happened later. For example, if
461        (?(?=(a))a) was matched against "a", no capturing was returned.
462    
463    26. When studying a pattern that contained subroutine calls or assertions,
464        the code for finding the minimum length of a possible match was handling
465        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
466        group 1 called group 2 while simultaneously a separate group 2 called group
467        1). A stack overflow occurred in this case. I have fixed this by limiting
468        the recursion depth to 10.
469    
470    27. Updated RunTest.bat in the distribution to the version supplied by Tom
471        Fortmann. This supports explicit test numbers on the command line, and has
472        argument validation and error reporting.
473    
474    28. An instance of \X with an unlimited repeat could fail if at any point the
475        first character it looked at was a mark character.
476    
477    29. Some minor code refactoring concerning Unicode properties and scripts
478        should reduce the stack requirement of match() slightly.
479    
480    30. Added the '=' option to pcretest to check the setting of unused capturing
481        slots at the end of the pattern, which are documented as being -1, but are
482        not included in the return count.
483    
484    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
485        compiled something random. Now it gives a compile-time error (as does
486        Perl).
487    
488    32. A *MARK encountered during the processing of a positive assertion is now
489        recorded and passed back (compatible with Perl).
490    
491    33. If --only-matching or --colour was set on a pcregrep call whose pattern
492        had alternative anchored branches, the search for a second match in a line
493        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
494        matched the line "0102" twice. The same bug affected patterns that started
495        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
496        twice.
497    
498    34. Previously, PCRE did not allow quantification of assertions. However, Perl
499        does, and because of capturing effects, quantifying parenthesized
500        assertions may at times be useful. Quantifiers are now allowed for
501        parenthesized assertions.
502    
503    35. A minor code tidy in pcre_compile() when checking options for \R usage.
504    
505    36. \g was being checked for fancy things in a character class, when it should
506        just be a literal "g".
507    
508    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
509        appearance of a nested POSIX class supersedes an apparent external class.
510        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
511        unescaped square brackets may also appear as part of class names. For
512        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
513        more like Perl. (But see 8.20/1 above.)
514    
515    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
516        was because it thought it was \N{name}, which is not supported).
517    
518    39. Add minix to OS list not supporting the -S option in pcretest.
519    
520    40. PCRE tries to detect cases of infinite recursion at compile time, but it
521        cannot analyze patterns in sufficient detail to catch mutual recursions
522        such as ((?1))((?2)). There is now a runtime test that gives an error if a
523        subgroup is called recursively as a subpattern for a second time at the
524        same position in the subject string. In previous releases this might have
525        been caught by the recursion limit, or it might have run out of stack.
526    
527    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
528        happen only once. PCRE was, however incorrectly giving a compile time error
529        "recursive call could loop indefinitely" because it cannot analyze the
530        pattern in sufficient detail. The compile time test no longer happens when
531        PCRE is compiling a conditional subpattern, but actual runaway loops are
532        now caught at runtime (see 40 above).
533    
534    42. It seems that Perl allows any characters other than a closing parenthesis
535        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
536        has been changed to be the same.
537    
538    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
539        as not to get warnings when autogen.sh is called. Also changed
540        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
541    
542    44. To help people who use pcregrep to scan files containing exceedingly long
543        lines, the following changes have been made:
544    
545        (a) The default value of the buffer size parameter has been increased from
546            8K to 20K. (The actual buffer used is three times this size.)
547    
548        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
549            PCRE is built.
550    
551        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
552            to be set at run time.
553    
554        (d) Numerical values in pcregrep options can be followed by K or M, for
555            example --buffer-size=50K.
556    
557        (e) If a line being scanned overflows pcregrep's buffer, an error is now
558            given and the return code is set to 2.
559    
560    45. Add a pointer to the latest mark to the callout data block.
561    
562    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
563        partial match of an empty string instead of no match. This was specific to
564        the use of ".".
565    
566    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
567        complete match instead of a partial match. This bug was dependent on both
568        the PCRE_UTF8 and PCRE_DOTALL options being set.
569    
570    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
571        starting byte set, because \b was not being ignored.
572    
573    
574    Version 8.12 15-Jan-2011
575    ------------------------
576    
577    1.  Fixed some typos in the markup of the man pages, and wrote a script that
578        checks for such things as part of the documentation building process.
579    
580    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
581        --match-limit and --recursion-limit options (added for 8.11). In
582        particular, this made one of the standard tests fail. (The integer value
583        went into the wrong half of a long int.)
584    
585    3.  If the --colour option was given to pcregrep with -v (invert match), it
586        did strange things, either producing crazy output, or crashing. It should,
587        of course, ignore a request for colour when reporting lines that do not
588        match.
589    
590    4.  Another pcregrep bug caused similar problems if --colour was specified with
591        -M (multiline) and the pattern match finished with a line ending.
592    
593    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
594        matched in multiline mode, the following line was shown as part of the
595        match. This seems wrong, so I have changed it.
596    
597    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
598        the check for further matches in the same line (so they could be coloured)
599        to overrun the end of the current line. If another match was found, it was
600        incorrectly shown (and then shown again when found in the next line).
601    
602    7.  If pcregrep was compiled under Windows, there was a reference to the
603        function pcregrep_exit() before it was defined. I am assuming this was
604        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
605        reported by a user. I've moved the definition above the reference.
606    
607    
608    Version 8.11 10-Dec-2010
609    ------------------------
610    
611    1.  (*THEN) was not working properly if there were untried alternatives prior
612        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
613        backtracked to try for "b" instead of moving to the next alternative branch
614        at the same level (in this case, to look for "c"). The Perl documentation
615        is clear that when (*THEN) is backtracked onto, it goes to the "next
616        alternative in the innermost enclosing group".
617    
618    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
619        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
620        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
621        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
622        (*THEN).
623    
624    3.  If \s appeared in a character class, it removed the VT character from
625        the class, even if it had been included by some previous item, for example
626        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
627        of \s, but is part of the POSIX "space" class.)
628    
629    4.  A partial match never returns an empty string (because you can always
630        match an empty string at the end of the subject); however the checking for
631        an empty string was starting at the "start of match" point. This has been
632        changed to the "earliest inspected character" point, because the returned
633        data for a partial match starts at this character. This means that, for
634        example, /(?<=abc)def/ gives a partial match for the subject "abc"
635        (previously it gave "no match").
636    
637    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
638        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
639        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
640        has an implication that the given string is incomplete (because a partial
641        match is preferred over a full match). For this reason, these items now
642        give a partial match in this situation. [Aside: previously, the one case
643        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
644        match rather than a full match, which was wrong by the old rules, but is
645        now correct.]
646    
647    6.  There was a bug in the handling of #-introduced comments, recognized when
648        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
649        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
650        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
651        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
652        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
653        places in pcre_compile().
654    
655    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
656        comments when looking ahead for named forward references to subpatterns,
657        the only newline sequence it recognized was NL. It now handles newlines
658        according to the set newline convention.
659    
660    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
661        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
662        cater for a lack of strerror(). These oversights have been fixed.
663    
664    9.  Added --match-limit and --recursion-limit to pcregrep.
665    
666    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
667    
668    11. When the -o option was used, pcregrep was setting a return code of 1, even
669        when matches were found, and --line-buffered was not being honoured.
670    
671    12. Added an optional parentheses number to the -o and --only-matching options
672        of pcregrep.
673    
674    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
675        can match an empty string. The code to do it in pcretest and pcredemo
676        needed fixing:
677    
678        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
679            only one byte after an empty string match just before CRLF (this case
680            just got forgotten; "any" and "anycrlf" were OK).
681    
682        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
683            mode when an empty string match preceded an ASCII character followed by
684            a non-ASCII character. (The code for advancing by one character rather
685            than one byte was nonsense.)
686    
687        (c) The pcredemo.c sample program did not have any code at all to handle
688            the cases when CRLF is a valid newline sequence.
689    
690    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
691        as a starting offset was within the subject string. There is now a new
692        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
693        negative or greater than the length of the string. In order to test this,
694        pcretest is extended to allow the setting of negative starting offsets.
695    
696    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
697        starting offset points to the beginning of a UTF-8 character was
698        unnecessarily clumsy. I tidied it up.
699    
700    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
701        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
702    
703    17. Nobody had reported that the --include_dir option, which was added in
704        release 7.7 should have been called --include-dir (hyphen, not underscore)
705        for compatibility with GNU grep. I have changed it to --include-dir, but
706        left --include_dir as an undocumented synonym, and the same for
707        --exclude-dir, though that is not available in GNU grep, at least as of
708        release 2.5.4.
709    
710    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
711        characters from a string of bytes) have been redefined so as not to use
712        loops, in order to improve performance in some environments. At the same
713        time, I abstracted some of the common code into auxiliary macros to save
714        repetition (this should not affect the compiled code).
715    
716    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
717        compile-time error is now given if \c is not followed by an ASCII
718        character, that is, a byte less than 128. (In EBCDIC mode, the code is
719        different, and any byte value is allowed.)
720    
721    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
722        START_OPTIMIZE option, which is now allowed at compile time - but just
723        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
724        to pcregrep and other applications that have no direct access to PCRE
725        options. The new /Y option in pcretest sets this option when calling
726        pcre_compile().
727    
728    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
729        back references. Groups containing recursive back references were forced to
730        be atomic by that change, but in the case of named groups, the amount of
731        memory required was incorrectly computed, leading to "Failed: internal
732        error: code overflow". This has been fixed.
733    
734    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
735        pcretest.c, to avoid build problems in some Borland environments.
736    
737    
738    Version 8.10 25-Jun-2010
739    ------------------------
740    
741    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
742        THEN.
743    
744    2.  (*ACCEPT) was not working when inside an atomic group.
745    
746    3.  Inside a character class, \B is treated as a literal by default, but
747        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
748        causes the error). The code is unchanged, but I tidied the documentation.
749    
750    4.  Inside a character class, PCRE always treated \R and \X as literals,
751        whereas Perl faults them if its -w option is set. I have changed PCRE so
752        that it faults them when PCRE_EXTRA is set.
753    
754    5.  Added support for \N, which always matches any character other than
755        newline. (It is the same as "." when PCRE_DOTALL is not set.)
756    
757    6.  When compiling pcregrep with newer versions of gcc which may have
758        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
759        declared with attribute warn_unused_result" were given. Just casting the
760        result to (void) does not stop the warnings; a more elaborate fudge is
761        needed. I've used a macro to implement this.
762    
763    7.  Minor change to pcretest.c to avoid a compiler warning.
764    
765    8.  Added four artifical Unicode properties to help with an option to make
766        \s etc use properties (see next item). The new properties are: Xan
767        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
768    
769    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
770        use Unicode properties. (*UCP) at the start of a pattern can be used to set
771        this option. Modified pcretest to add /W to test this facility. Added
772        REG_UCP to make it available via the POSIX interface.
773    
774    10. Added --line-buffered to pcregrep.
775    
776    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
777        studied, and the match started with a letter with a code point greater than
778        127 whose first byte was different to the first byte of the other case of
779        the letter, the other case of this starting letter was not recognized
780        (#976).
781    
782    12. If a pattern that was studied started with a repeated Unicode property
783        test, for example, \p{Nd}+, there was the theoretical possibility of
784        setting up an incorrect bitmap of starting bytes, but fortunately it could
785        not have actually happened in practice until change 8 above was made (it
786        added property types that matched character-matching opcodes).
787    
788    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
789        possible starting bytes for non-anchored patterns.
790    
791    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
792        \R, and also a number of cases that involve Unicode properties, both
793        explicit and implicit when PCRE_UCP is set.
794    
795    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
796        input, it could crash or give wrong results if characters with values
797        greater than 0xc0 were present in the subject string. (Detail: it assumed
798        UTF-8 input when processing these items.)
799    
800    16. Added a lot of (int) casts to avoid compiler warnings in systems where
801        size_t is 64-bit (#991).
802    
803    17. Added a check for running out of memory when PCRE is compiled with
804        --disable-stack-for-recursion (#990).
805    
806    18. If the last data line in a file for pcretest does not have a newline on
807        the end, a newline was missing in the output.
808    
809    19. The default pcre_chartables.c file recognizes only ASCII characters (values
810        less than 128) in its various bitmaps. However, there is a facility for
811        generating tables according to the current locale when PCRE is compiled. It
812        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
813        characters, are recognized by isspace() and therefore were getting set in
814        these tables, and indeed these tables seem to approximate to ISO 8859. This
815        caused a problem in UTF-8 mode when pcre_study() was used to create a list
816        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
817        which of course cannot start UTF-8 characters. I have changed the code so
818        that only real ASCII characters (less than 128) and the correct starting
819        bytes for UTF-8 encodings are set for characters greater than 127 when in
820        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
821        altogether.)
822    
823    20. Added the /T option to pcretest so as to be able to run tests with non-
824        standard character tables, thus making it possible to include the tests
825        used for 19 above in the standard set of tests.
826    
827    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
828        reference to a subpattern the other side of a comment that contains an
829        opening parenthesis caused either an internal compiling error, or a
830        reference to the wrong subpattern.
831    
832    
833    Version 8.02 19-Mar-2010
834    ------------------------
835    
836    1.  The Unicode data tables have been updated to Unicode 5.2.0.
837    
838    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
839        configured.
840    
841    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
842        original author of that file, following a query about its status.
843    
844    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
845        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
846    
847    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
848        quantifier applied to a forward-referencing subroutine call, could compile
849        incorrect code or give the error "internal error: previously-checked
850        referenced subpattern not found".
851    
852    6.  Both MS Visual Studio and Symbian OS have problems with initializing
853        variables to point to external functions. For these systems, therefore,
854        pcre_malloc etc. are now initialized to local functions that call the
855        relevant global functions.
856    
857    7.  There were two entries missing in the vectors called coptable and poptable
858        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
859        I've fixed the data, and added a kludgy way of testing at compile time that
860        the lengths are correct (equal to the number of opcodes).
861    
862    8.  Following on from 7, I added a similar kludge to check the length of the
863        eint vector in pcreposix.c.
864    
865    9.  Error texts for pcre_compile() are held as one long string to avoid too
866        much relocation at load time. To find a text, the string is searched,
867        counting zeros. There was no check for running off the end of the string,
868        which could happen if a new error number was added without updating the
869        string.
870    
871    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
872    
873    11. \K was not working if it appeared in an atomic group or in a group that
874        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
875        \K is "not well defined" if used in an assertion. PCRE now accepts it if
876        the assertion is positive, but not if it is negative.
877    
878    12. Change 11 fortuitously reduced the size of the stack frame used in the
879        "match()" function of pcre_exec.c by one pointer. Forthcoming
880        implementation of support for (*MARK) will need an extra pointer on the
881        stack; I have reserved it now, so that the stack frame size does not
882        decrease.
883    
884    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
885        item in branch that calls a recursion is a subroutine call - as in the
886        second branch in the above example - was incorrectly given the compile-
887        time error "recursive call could loop indefinitely" because pcre_compile()
888        was not correctly checking the subroutine for matching a non-empty string.
889    
890    14. The checks for overrunning compiling workspace could trigger after an
891        overrun had occurred. This is a "should never occur" error, but it can be
892        triggered by pathological patterns such as hundreds of nested parentheses.
893        The checks now trigger 100 bytes before the end of the workspace.
894    
895    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
896    
897    
898    Version 8.01 19-Jan-2010
899    ------------------------
900    
901    1.  If a pattern contained a conditional subpattern with only one branch (in
902        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
903        computed the wrong minimum data length (which is of course zero for such
904        subpatterns). This could cause incorrect "no match" results.
905    
906    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
907        the pattern is reset in the first branch, pcre_compile() failed with
908        "internal error: code overflow at offset...". This happened only when
909        the reset was to the original external option setting. (An optimization
910        abstracts leading options settings into an external setting, which was the
911        cause of this.)
912    
913    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
914        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
915        assertion pattern did not match (meaning that the assertion was true), it
916        was incorrectly treated as false if the SKIP had been reached during the
917        matching. This also applied to assertions used as conditions.
918    
919    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
920        assertion subpattern, including such a pattern used as a condition,
921        unpredictable results occurred, instead of the error return
922        PCRE_ERROR_DFA_UITEM.
923    
924    5.  The C++ GlobalReplace function was not working like Perl for the special
925        situation when an empty string is matched. It now does the fancy magic
926        stuff that is necessary.
927    
928    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
929        removed. (These were left over from very, very early versions of PCRE.)
930    
931    7.  Some cosmetic changes to the code to make life easier when compiling it
932        as part of something else:
933    
934        (a) Change DEBUG to PCRE_DEBUG.
935    
936        (b) In pcre_compile(), rename the member of the "branch_chain" structure
937            called "current" as "current_branch", to prevent a collision with the
938            Linux macro when compiled as a kernel module.
939    
940        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
941            prevent a collision with the Linux macro when compiled as a kernel
942            module.
943    
944    8.  In pcre_compile() there are some checks for integer overflows that used to
945        cast potentially large values to (double). This has been changed to that
946        when building, a check for int64_t is made, and if it is found, it is used
947        instead, thus avoiding the use of floating point arithmetic. (There is no
948        other use of FP in PCRE.) If int64_t is not found, the fallback is to
949        double.
950    
951    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
952        2005 (difference between two addresses compared to an unsigned value).
953    
954    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
955        custom one, because of the following reported problem in Windows:
956    
957          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
958              under Win32.
959          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
960              therefore missing the function definition.
961          - The compiler thus generates a "C" signature for the test function.
962          - The linker fails to find the "C" function.
963          - PCRE fails to configure if asked to do so against libbz2.
964    
965    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
966        messages were output:
967    
968          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
969          rerunning libtoolize, to keep the correct libtool macros in-tree.
970          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
971    
972        I have done both of these things.
973    
974    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
975        most of the time, it *can* run out if it is given a pattern that contains a
976        runaway infinite recursion. I updated the discussion in the pcrestack man
977        page.
978    
979    13. Now that we have gone to the x.xx style of version numbers, the minor
980        version may start with zero. Using 08 or 09 is a bad idea because users
981        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
982        interpreted as invalid octal numbers. I've updated the previous comment in
983        configure.ac, and also added a check that gives an error if 08 or 09 are
984        used.
985    
986    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
987        causing partial matching to fail when the end of the subject matched \W
988        in a UTF-8 pattern where \W was quantified with a minimum of 3.
989    
990    15. There were some discrepancies between the declarations in pcre_internal.h
991        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
992        their definitions. The declarations used "const uschar *" and the
993        definitions used USPTR. Even though USPTR is normally defined as "const
994        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
995        reported that: "This difference in casting confuses some C++ compilers, for
996        example, SunCC recognizes above declarations as different functions and
997        generates broken code for hbpcre." I have changed the declarations to use
998        USPTR.
999    
1000    16. GNU libtool is named differently on some systems. The autogen.sh script now
1001        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1002        (FreeBSD).
1003    
1004    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1005        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1006        comment: "Figure out how to create a longlong from a string: strtoll and
1007        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1008        instance, but it only takes 2 args instead of 3!"
1009    
1010    18. A subtle bug concerned with back references has been fixed by a change of
1011        specification, with a corresponding code fix. A pattern such as
1012        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1013        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1014        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1015        same bug. Such groups have to be quantified to be useful, or contained
1016        inside another quantified group. (If there's no repetition, the reference
1017        can never match.) The problem arises because, having left the group and
1018        moved on to the rest of the pattern, a later failure that backtracks into
1019        the group uses the captured value from the final iteration of the group
1020        rather than the correct earlier one. I have fixed this in PCRE by forcing
1021        any group that contains a reference to itself to be an atomic group; that
1022        is, there cannot be any backtracking into it once it has completed. This is
1023        similar to recursive and subroutine calls.
1024    
1025    
1026    Version 8.00 19-Oct-09
1027    ----------------------
1028    
1029    1.  The table for translating pcre_compile() error codes into POSIX error codes
1030        was out-of-date, and there was no check on the pcre_compile() error code
1031        being within the table. This could lead to an OK return being given in
1032        error.
1033    
1034    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1035        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1036        in a Windows environment.
1037    
1038    3.  The pcregrep --count option prints the count for each file even when it is
1039        zero, as does GNU grep. However, pcregrep was also printing all files when
1040        --files-with-matches was added. Now, when both options are given, it prints
1041        counts only for those files that have at least one match. (GNU grep just
1042        prints the file name in this circumstance, but including the count seems
1043        more useful - otherwise, why use --count?) Also ensured that the
1044        combination -clh just lists non-zero counts, with no names.
1045    
1046    4.  The long form of the pcregrep -F option was incorrectly implemented as
1047        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1048        but it seems right to fix it, and I didn't think it was worth preserving
1049        the old behaviour.
1050    
1051    5.  The command line items --regex=pattern and --regexp=pattern were not
1052        recognized by pcregrep, which required --regex pattern or --regexp pattern
1053        (with a space rather than an '='). The man page documented the '=' forms,
1054        which are compatible with GNU grep; these now work.
1055    
1056    6.  No libpcreposix.pc file was created for pkg-config; there was just
1057        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1058    
1059    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1060        when UCP support is not needed, by modifying the Python script that
1061        generates it from Unicode data files. This should not matter if the module
1062        is correctly used as a library, but I received one complaint about 50K of
1063        unwanted data. My guess is that the person linked everything into his
1064        program rather than using a library. Anyway, it does no harm.
1065    
1066    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1067        was a minimum greater than 1 for a wide character in a possessive
1068        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1069        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1070        character. Chaos in the form of incorrect output or a compiling loop could
1071        result.
1072    
1073    9.  The restrictions on what a pattern can contain when partial matching is
1074        requested for pcre_exec() have been removed. All patterns can now be
1075        partially matched by this function. In addition, if there are at least two
1076        slots in the offset vector, the offset of the earliest inspected character
1077        for the match and the offset of the end of the subject are set in them when
1078        PCRE_ERROR_PARTIAL is returned.
1079    
1080    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1081        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1082        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1083        and may be more useful for multi-segment matching.
1084    
1085    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1086        used to be given if ever the end of the subject was reached; now it is
1087        given only if matching could not proceed because another character was
1088        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1089        string "Z", which now yields "no match" instead of "partial match". In the
1090        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1091        final character ended with (*FAIL).
1092    
1093    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1094        if the pattern had a "must contain" character that was already found in the
1095        earlier partial match, unless partial matching was again requested. For
1096        example, with the pattern /dog.(body)?/, the "must contain" character is
1097        "g". If the first part-match was for the string "dog", restarting with
1098        "sbody" failed. This bug has been fixed.
1099    
1100    13. The string returned by pcre_dfa_exec() after a partial match has been
1101        changed so that it starts at the first inspected character rather than the
1102        first character of the match. This makes a difference only if the pattern
1103        starts with a lookbehind assertion or \b or \B (\K is not supported by
1104        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1105        matching functions compatible, and I think it's the right thing to do.
1106    
1107    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1108        so that the demonstration program is easily available in environments where
1109        PCRE has not been installed from source.
1110    
1111    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1112        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1113        library.
1114    
1115    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1116        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1117        is not the first non-POSIX option to be added. Clearly some people find
1118        these options useful.
1119    
1120    17. If a caller to the POSIX matching function regexec() passes a non-zero
1121        value for nmatch with a NULL value for pmatch, the value of
1122        nmatch is forced to zero.
1123    
1124    18. RunGrepTest did not have a test for the availability of the -u option of
1125        the diff command, as RunTest does. It now checks in the same way as
1126        RunTest, and also checks for the -b option.
1127    
1128    19. If an odd number of negated classes containing just a single character
1129        interposed, within parentheses, between a forward reference to a named
1130        subpattern and the definition of the subpattern, compilation crashed with
1131        an internal error, complaining that it could not find the referenced
1132        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1133        [The bug was that it was starting one character too far in when skipping
1134        over the character class, thus treating the ] as data rather than
1135        terminating the class. This meant it could skip too much.]
1136    
1137    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1138        /g option in pcretest when the pattern contains \K, which makes it possible
1139        to have an empty string match not at the start, even when the pattern is
1140        anchored. Updated pcretest and pcredemo to use this option.
1141    
1142    21. If the maximum number of capturing subpatterns in a recursion was greater
1143        than the maximum at the outer level, the higher number was returned, but
1144        with unset values at the outer level. The correct (outer level) value is
1145        now given.
1146    
1147    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1148        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1149        make it do so. The string so far is captured, making this feature
1150        compatible with Perl.
1151    
1152    23. The tests have been re-organized, adding tests 11 and 12, to make it
1153        possible to check the Perl 5.10 features against Perl 5.10.
1154    
1155    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1156        pattern matches a fixed length string. PCRE did not allow this; now it
1157        does. Neither allows recursion.
1158    
1159    25. I finally figured out how to implement a request to provide the minimum
1160        length of subject string that was needed in order to match a given pattern.
1161        (It was back references and recursion that I had previously got hung up
1162        on.) This code has now been added to pcre_study(); it finds a lower bound
1163        to the length of subject needed. It is not necessarily the greatest lower
1164        bound, but using it to avoid searching strings that are too short does give
1165        some useful speed-ups. The value is available to calling programs via
1166        pcre_fullinfo().
1167    
1168    26. While implementing 25, I discovered to my embarrassment that pcretest had
1169        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1170        study optimizations had never been tested with that matching function.
1171        Oops. What is worse, even when it was passed study data, there was a bug in
1172        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1173        were also very few tests of studied patterns with pcre_dfa_exec().
1174    
1175    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1176        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1177        on the other side of the coin, they are no longer allowed to have different
1178        names, because these cannot be distinguished in PCRE, and this has caused
1179        confusion. (This is a difference from Perl.)
1180    
1181    28. When duplicate subpattern names are present (necessarily with different
1182        numbers, as required by 27 above), and a test is made by name in a
1183        conditional pattern, either for a subpattern having been matched, or for
1184        recursion in such a pattern, all the associated numbered subpatterns are
1185        tested, and the overall condition is true if the condition is true for any
1186        one of them. This is the way Perl works, and is also more like the way
1187        testing by number works.
1188    
1189    
1190    Version 7.9 11-Apr-09
1191    ---------------------
1192    
1193    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1194        (pcretest), all targets were linked against these libraries. This included
1195        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1196        libraries. This caused unwanted dependencies to be created. This problem
1197        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1198        pcretest is linked with readline.
1199    
1200    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1201        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1202        moved outside it again, because FALSE and TRUE are already defined in AIX,
1203        but BOOL is not.
1204    
1205    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1206        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1207    
1208    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1209        hyphens) following file names and line numbers when outputting matching
1210        lines. This is not true; no spaces are inserted. I have also clarified the
1211        wording for the --colour (or --color) option.
1212    
1213    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1214        was not coloured; this is different to GNU grep, so I have changed it to be
1215        the same.
1216    
1217    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1218        each matching line was coloured. Now it goes on to look for further matches
1219        of any of the test patterns, which is the same behaviour as GNU grep.
1220    
1221    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1222        doesn't make sense to accept an empty string match in pcregrep, so I have
1223        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1224        seems to be how GNU grep behaves.
1225    
1226    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1227        start or after a newline", because the conditional assertion was not being
1228        correctly handled. The rule now is that both the assertion and what follows
1229        in the first alternative must satisfy the test.
1230    
1231    9.  If auto-callout was enabled in a pattern with a conditional group whose
1232        condition was an assertion, PCRE could crash during matching, both with
1233        pcre_exec() and pcre_dfa_exec().
1234    
1235    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1236        used for matching.
1237    
1238    11. Unicode property support in character classes was not working for
1239        characters (bytes) greater than 127 when not in UTF-8 mode.
1240    
1241    12. Added the -M command line option to pcretest.
1242    
1243    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1244    
1245    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1246    
1247    16. Added comments and documentation about mis-use of no_arg in the C++
1248        wrapper.
1249    
1250    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1251        from Martin Jerabek that uses macro names for all relevant character and
1252        string constants.
1253    
1254    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1255        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1256        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1257        these, but not everybody uses configure.
1258    
1259    19. A conditional group that had only one branch was not being correctly
1260        recognized as an item that could match an empty string. This meant that an
1261        enclosing group might also not be so recognized, causing infinite looping
1262        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1263        with the subject "ab", where knowledge that the repeated group can match
1264        nothing is needed in order to break the loop.
1265    
1266    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1267        exec(), but without supplying a callout function, matching went wrong.
1268    
1269    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1270        leak if the size of the offset vector was greater than 30. When the vector
1271        is smaller, the saved offsets during recursion go onto a local stack
1272        vector, but for larger vectors malloc() is used. It was failing to free
1273        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1274        error, in fact).
1275    
1276    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1277        heapframe that is used only when UTF-8 support is enabled. This caused no
1278        problem, but was untidy.
1279    
1280    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1281        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1282        included within another project.
1283    
1284    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1285        slightly modified by me:
1286    
1287          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1288              not building pcregrep.
1289    
1290          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1291              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1292    
1293    25. Forward references, both numeric and by name, in patterns that made use of
1294        duplicate group numbers, could behave incorrectly or give incorrect errors,
1295        because when scanning forward to find the reference group, PCRE was not
1296        taking into account the duplicate group numbers. A pattern such as
1297        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1298    
1299    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1300        the feature of a custom pointer more persuasive (as requested by a user).
1301    
1302    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1303        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1304        pre-defined.
1305    
1306    28. Added support for (*UTF8) at the start of a pattern.
1307    
1308    29. Arrange for flags added by the "release type" setting in CMake to be shown
1309        in the configuration summary.
1310    
1311    
1312    Version 7.8 05-Sep-08
1313    ---------------------
1314    
1315    1.  Replaced UCP searching code with optimized version as implemented for Ad
1316        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1317        stage table and inline lookup instead of a function, giving speed ups of 2
1318        to 5 times on some simple patterns that I tested. Permission was given to
1319        distribute the MultiStage2.py script that generates the tables (it's not in
1320        the tarball, but is in the Subversion repository).
1321    
1322    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1323        scripts.
1324    
1325    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1326        a group with a zero qualifier. The result of the study could be incorrect,
1327        or the function might crash, depending on the pattern.
1328    
1329    4.  Caseless matching was not working for non-ASCII characters in back
1330        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1331        It now works when Unicode Property Support is available.
1332    
1333    5.  In pcretest, an escape such as \x{de} in the data was always generating
1334        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1335        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1336        truncation.
1337    
1338    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1339    
1340    7.  Added two (int) casts to pcregrep when printing the difference of two
1341        pointers, in case they are 64-bit values.
1342    
1343    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1344        test 2 if it fails.
1345    
1346    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1347        and a #define of that name to empty if it is not externally set. This is to
1348        allow users of MSVC to set it if necessary.
1349    
1350    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1351        the convenience functions in the pcre_get.c source file.
1352    
1353    11. An option change at the start of a pattern that had top-level alternatives
1354        could cause overwriting and/or a crash. This command provoked a crash in
1355        some environments:
1356    
1357          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1358    
1359        This potential security problem was recorded as CVE-2008-2371.
1360    
1361    12. For a pattern where the match had to start at the beginning or immediately
1362        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1363        pcre_dfa_exec() could read past the end of the passed subject if there was
1364        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1365        pcretest so that it places the subject at the end of its malloc-ed buffer.
1366    
1367    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1368        exec() might read past the end of the data buffer in UTF-8 mode.
1369    
1370    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1371        the data contained the byte 0x85 as part of a UTF-8 character within its
1372        first line. This applied both to normal and DFA matching.
1373    
1374    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1375        /^[^d]*?$/8 failed to match "abc".
1376    
1377    16. Added a missing copyright notice to pcrecpp_internal.h.
1378    
1379    17. Make it more clear in the documentation that values returned from
1380        pcre_exec() in ovector are byte offsets, not character counts.
1381    
1382    18. Tidied a few places to stop certain compilers from issuing warnings.
1383    
1384    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1385        supplied by Stefan Weber. I made a further small update for 7.8 because
1386        there is a change of source arrangements: the pcre_searchfuncs.c module is
1387        replaced by pcre_ucd.c.
1388    
1389    
1390    Version 7.7 07-May-08
1391    ---------------------
1392    
1393    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1394        a string to a long long, pretend we don't even have a long long." This is
1395        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1396    
1397    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1398        pre-7.6 versions, which defined a global no_arg variable instead of putting
1399        it in the RE class. (See also #8 below.)
1400    
1401    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1402        Lopes.
1403    
1404    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1405    
1406        (1) The include/exclude patterns were being applied to the whole pathnames
1407            of files, instead of just to the final components.
1408    
1409        (2) If there was more than one level of directory, the subdirectories were
1410            skipped unless they satisfied the include/exclude conditions. This is
1411            inconsistent with GNU grep (and could even be seen as contrary to the
1412            pcregrep specification - which I improved to make it absolutely clear).
1413            The action now is always to scan all levels of directory, and just
1414            apply the include/exclude patterns to regular files.
1415    
1416    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1417        --exclude_dir in the tests to avoid scanning .svn directories.
1418    
1419    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1420        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1421        doesn't support NULs in patterns.
1422    
1423    7.  Added some missing "const"s to declarations of static tables in
1424        pcre_compile.c and pcre_dfa_exec.c.
1425    
1426    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1427        caused by fix #2  above. (Subsequently also a second patch to fix the
1428        first patch. And a third patch - this was a messy problem.)
1429    
1430    9.  Applied Craig's patch to remove the use of push_back().
1431    
1432    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1433        matching function regexec().
1434    
1435    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1436        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1437        references. PCRE supports relative numbers with this syntax (I don't think
1438        Oniguruma does).
1439    
1440    12. Previously, a group with a zero repeat such as (...){0} was completely
1441        omitted from the compiled regex. However, this means that if the group
1442        was called as a subroutine from elsewhere in the pattern, things went wrong
1443        (an internal error was given). Such groups are now left in the compiled
1444        pattern, with a new opcode that causes them to be skipped at execution
1445        time.
1446    
1447    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1448        to the way PCRE behaves:
1449    
1450        (a) A lone ] character is dis-allowed (Perl treats it as data).
1451    
1452        (b) A back reference to an unmatched subpattern matches an empty string
1453            (Perl fails the current match path).
1454    
1455        (c) A data ] in a character class must be notated as \] because if the
1456            first data character in a class is ], it defines an empty class. (In
1457            Perl it is not possible to have an empty class.) The empty class []
1458            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1459            The negative empty class [^] matches any one character, independently
1460            of the DOTALL setting.
1461    
1462    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1463        non-existent subpattern following a character class starting with ']' and
1464        containing () gave an internal compiling error instead of "reference to
1465        non-existent subpattern". Fortunately, when the pattern did exist, the
1466        compiled code was correct. (When scanning forwards to check for the
1467        existencd of the subpattern, it was treating the data ']' as terminating
1468        the class, so got the count wrong. When actually compiling, the reference
1469        was subsequently set up correctly.)
1470    
1471    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1472        it was being rejected as not supported by pcre_dfa_exec(), even though
1473        other assertions are supported. I have made pcre_dfa_exec() support
1474        (*FAIL).
1475    
1476    16. The implementation of 13c above involved the invention of a new opcode,
1477        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1478        cannot be changed at match time, I realized I could make a small
1479        improvement to matching performance by compiling OP_ALLANY instead of
1480        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1481        on the OP_ANY path.
1482    
1483    17. Compiling pcretest on Windows with readline support failed without the
1484        following two fixes: (1) Make the unistd.h include conditional on
1485        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1486    
1487    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1488        ncurses library to be included for pcretest when ReadLine support is
1489        requested, but also to allow for it to be overridden. This patch came from
1490        Daniel Bergström.
1491    
1492    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1493        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1494        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1495        spotting this.
1496    
1497    
1498    Version 7.6 28-Jan-08
1499    ---------------------
1500    
1501    1.  A character class containing a very large number of characters with
1502        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1503        overflow.
1504    
1505    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1506        HAVE_LONG_LONG is not defined.
1507    
1508    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1509        bring them up to date and include new features. This patch includes:
1510    
1511        - Fixed PH's badly added libz and libbz2 support.
1512        - Fixed a problem with static linking.
1513        - Added pcredemo. [But later removed - see 7 below.]
1514        - Fixed dftables problem and added an option.
1515        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1516            HAVE_LONG_LONG.
1517        - Added readline support for pcretest.
1518        - Added an listing of the option settings after cmake has run.
1519    
1520    4.  A user submitted a patch to Makefile that makes it easy to create
1521        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1522        Makefile.am that cause it to include this special target, without
1523        affecting anything else. Note that the same mingw target plus all
1524        the other distribution libraries and programs are now supported
1525        when configuring with CMake (see 6 below) instead of with
1526        Configure/Make.
1527    
1528    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1529        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1530        exported in the Windows port". It has not yet been confirmed that the patch
1531        solves the problem, but it does no harm.
1532    
1533    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1534        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1535        with CMake, and also correct the comment about stack recursion.
1536    
1537    7.  Remove the automatic building of pcredemo from the ./configure system and
1538        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1539        of a program that users should build themselves after PCRE is installed, so
1540        building it automatically is not really right. What is more, it gave
1541        trouble in some build environments.
1542    
1543    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1544    
1545    
1546    Version 7.5 10-Jan-08
1547    ---------------------
1548    
1549    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1550        values in parens when parsing an RE using the C++ wrapper."
1551    
1552    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1553        Characters greater than 255 were excluded from the class instead of being
1554        included.
1555    
1556    3.  The same bug as (2) above applied to negated POSIX classes such as
1557        [:^space:].
1558    
1559    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1560        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1561        I have changed it.
1562    
1563    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1564        first named subpattern) and a construct such as (?&a) would reference the
1565        first named subpattern whose name started with "a" (in other words, the
1566        length check was missing). Both these problems are fixed. "Subpattern name
1567        expected" is now given for (?&) (a zero-length name), and this patch also
1568        makes it give the same error for \k'' (previously it complained that that
1569        was a reference to a non-existent subpattern).
1570    
1571    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1572        this is right because (?- can be followed by option settings as well as by
1573        digits. I have, however, made the messages clearer.
1574    
1575    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1576        than the number used in the conditional) now cause a compile-time error.
1577        This is actually not compatible with Perl, which accepts such patterns, but
1578        treats the conditional as always being FALSE (as PCRE used to), but it
1579        seems to me that giving a diagnostic is better.
1580    
1581    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1582        and messages.
1583    
1584    9.  Fix two occurrences of "backslash" in comments that should have been
1585        "backspace".
1586    
1587    10. Remove two redundant lines of code that can never be obeyed (their function
1588        was moved elsewhere).
1589    
1590    11. The program that makes PCRE's Unicode character property table had a bug
1591        which caused it to generate incorrect table entries for sequences of
1592        characters that have the same character type, but are in different scripts.
1593        It amalgamated them into a single range, with the script of the first of
1594        them. In other words, some characters were in the wrong script. There were
1595        thirteen such cases, affecting characters in the following ranges:
1596    
1597          U+002b0 - U+002c1
1598          U+0060c - U+0060d
1599          U+0061e - U+00612
1600          U+0064b - U+0065e
1601          U+0074d - U+0076d
1602          U+01800 - U+01805
1603          U+01d00 - U+01d77
1604          U+01d9b - U+01dbf
1605          U+0200b - U+0200f
1606          U+030fc - U+030fe
1607          U+03260 - U+0327f
1608          U+0fb46 - U+0fbb1
1609          U+10450 - U+1049d
1610    
1611    12. The -o option (show only the matching part of a line) for pcregrep was not
1612        compatible with GNU grep in that, if there was more than one match in a
1613        line, it showed only the first of them. It now behaves in the same way as
1614        GNU grep.
1615    
1616    13. If the -o and -v options were combined for pcregrep, it printed a blank
1617        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1618        does the same. The return code can be used to tell if there were any
1619        non-matching lines.
1620    
1621    14. Added --file-offsets and --line-offsets to pcregrep.
1622    
1623    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1624        infinitely looping recursion. The bug was that positive lookaheads were not
1625        being skipped when checking for a possible empty match (negative lookaheads
1626        and both kinds of lookbehind were skipped).
1627    
1628    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1629        inclusion of <windows.h> to before rather than after the definition of
1630        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1631    
1632    17. Specifying a possessive quantifier with a specific limit for a Unicode
1633        character property caused pcre_compile() to compile bad code, which led at
1634        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1635        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1636        caused the error; without that there was no problem.
1637    
1638    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1639    
1640    19. Added --enable-pcretest-libreadline.
1641    
1642    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1643        RE::GlobalReplace(). As a result, the number of replacements returned was
1644        double what it should be. I removed one of the increments, but Craig sent a
1645        later patch that removed the other one (the right fix) and added unit tests
1646        that check the return values (which was not done before).
1647    
1648    21. Several CMake things:
1649    
1650        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1651            the names libpcre and libpcreposix, not just pcre and pcreposix.
1652    
1653        (2) The above change means that pcretest and pcregrep are now correctly
1654            linked with the newly-built libraries, not previously installed ones.
1655    
1656        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1657    
1658    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1659        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1660        UTF-8 newline character). The key issue is that the pattern starts .*;
1661        this means that the match must be either at the beginning, or after a
1662        newline. The bug was in the code for advancing after a failed match and
1663        checking that the new position followed a newline. It was not taking
1664        account of UTF-8 characters correctly.
1665    
1666    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1667        character classes. PCRE was not treating the sequence [:...:] as a
1668        character class unless the ... were all letters. Perl, however, seems to
1669        allow any characters between [: and :], though of course it rejects as
1670        unknown any "names" that contain non-letters, because all the known class
1671        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1672        for example, whereas PCRE did not - it did not recognize a POSIX character
1673        class. This seemed a bit dangerous, so the code has been changed to be
1674        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1675        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1676        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1677        Perl does, and where it didn't before.
1678    
1679    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1680        Windows environments %n is disabled by default.
1681    
1682    
1683    Version 7.4 21-Sep-07
1684    ---------------------
1685    
1686    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1687        means that a class such as [\s] counted as "explicit reference to CR or
1688        LF". That isn't really right - the whole point of the change was to try to
1689        help when there was an actual mention of one of the two characters. So now
1690        the change happens only if \r or \n (or a literal CR or LF) character is
1691        encountered.
1692    
1693    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1694        of both had grown to the point where there were only 3 bits left.
1695        Fortunately, there was spare space in the data structure, and so I have
1696        moved the internal flags into a new 16-bit field to free up more option
1697        bits.
1698    
1699    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1700        but did not set the internal JCHANGED flag - either of these is enough to
1701        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1702        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1703        start sets both bits.
1704    
1705    4.  Added options (at build time, compile time, exec time) to change \R from
1706        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1707    
1708    5.  doc/pcresyntax.html was missing from the distribution.
1709    
1710    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1711        compatibility, even though it is no longer used.
1712    
1713    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1714        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1715        windows.h file is present (where different names are used). [This was
1716        reversed later after testing - see 16 below.]
1717    
1718    8.  Changed all #include <config.h> to #include "config.h". There were also
1719        some further <pcre.h> cases that I changed to "pcre.h".
1720    
1721    9.  When pcregrep was used with the --colour option, it missed the line ending
1722        sequence off the lines that it output.
1723    
1724    10. It was pointed out to me that arrays of string pointers cause lots of
1725        relocations when a shared library is dynamically loaded. A technique of
1726        using a single long string with a table of offsets can drastically reduce
1727        these. I have refactored PCRE in four places to do this. The result is
1728        dramatic:
1729    
1730          Originally:                          290
1731          After changing UCP table:            187
1732          After changing error message table:   43
1733          After changing table of "verbs"       36
1734          After changing table of Posix names   22
1735    
1736        Thanks to the folks working on Gregex for glib for this insight.
1737    
1738    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1739        unicode-properties was also set.
1740    
1741    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1742    
1743    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1744        checked only for CRLF.
1745    
1746    14. Added casts to pcretest.c to avoid compiler warnings.
1747    
1748    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1749    
1750    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1751        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1752        entirely. This removes changes made in 7 above.
1753    
1754    17. The CMake files have been updated, and there is now more information about
1755        building with CMake in the NON-UNIX-USE document.
1756    
1757    
1758    Version 7.3 28-Aug-07
1759    ---------------------
1760    
1761     1. In the rejigging of the build system that eventually resulted in 7.1, the
1762        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1763        brackets there is not right, since it causes compilers to look for an
1764        installed pcre.h, not the version that is in the source that is being
1765        compiled (which of course may be different). I have changed it back to:
1766    
1767          #include "pcre.h"
1768    
1769        I have a vague recollection that the change was concerned with compiling in
1770        different directories, but in the new build system, that is taken care of
1771        by the VPATH setting the Makefile.
1772    
1773     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1774        when the subject happened to end in the byte 0x85 (e.g. if the last
1775        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1776        characters but of course it shouldn't be taken as a newline when it is part
1777        of another character. The bug was that, for an unlimited repeat of . in
1778        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1779        characters when looking for a newline.
1780    
1781     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1782    
1783     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1784        in debug output.
1785    
1786     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1787        long printing in the pcrecpp unittest when running under MinGW.
1788    
1789     6. ESC_K was left out of the EBCDIC table.
1790    
1791     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1792        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1793        limit also applies to "virtual nesting" when a pattern is recursive, and in
1794        this case 1000 isn't so big. I have been able to remove this limit at the
1795        expense of backing off one optimization in certain circumstances. Normally,
1796        when pcre_exec() would call its internal match() function recursively and
1797        immediately return the result unconditionally, it uses a "tail recursion"
1798        feature to save stack. However, when a subpattern that can match an empty
1799        string has an unlimited repetition quantifier, it no longer makes this
1800        optimization. That gives it a stack frame in which to save the data for
1801        checking that an empty string has been matched. Previously this was taken
1802        from the 1000-entry workspace that had been reserved. So now there is no
1803        explicit limit, but more stack is used.
1804    
1805     8. Applied Daniel's patches to solve problems with the import/export magic
1806        syntax that is required for Windows, and which was going wrong for the
1807        pcreposix and pcrecpp parts of the library. These were overlooked when this
1808        problem was solved for the main library.
1809    
1810     9. There were some crude static tests to avoid integer overflow when computing
1811        the size of patterns that contain repeated groups with explicit upper
1812        limits. As the maximum quantifier is 65535, the maximum group length was
1813        set at 30,000 so that the product of these two numbers did not overflow a
1814        32-bit integer. However, it turns out that people want to use groups that
1815        are longer than 30,000 bytes (though not repeat them that many times).
1816        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1817        made it possible to implement the integer overflow checks in a much more
1818        dynamic way, which I have now done. The artificial limitation on group
1819        length has been removed - we now have only the limit on the total length of
1820        the compiled pattern, which depends on the LINK_SIZE setting.
1821    
1822    10. Fixed a bug in the documentation for get/copy named substring when
1823        duplicate names are permitted. If none of the named substrings are set, the
1824        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1825        empty string.
1826    
1827    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1828        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1829        because the ] is interpreted as the first data character and the
1830        terminating ] is not found. PCRE has been made compatible with Perl in this
1831        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1832        cause memory overwriting.
1833    
1834    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1835        string has been matched (to stop an infinite loop). It was not recognizing
1836        a conditional subpattern that could match an empty string if that
1837        subpattern was within another subpattern. For example, it looped when
1838        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1839        condition was not nested. This bug has been fixed.
1840    
1841    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1842        past the start of the subject in the presence of bytes with the top bit
1843        set, for example "\x8aBCD".
1844    
1845    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1846        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1847    
1848    14. Optimized (?!) to (*FAIL).
1849    
1850    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1851        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1852        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1853        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1854        does: it's just the validity check that is more restrictive.
1855    
1856    16. Inserted checks for integer overflows during escape sequence (backslash)
1857        processing, and also fixed erroneous offset values for syntax errors during
1858        backslash processing.
1859    
1860    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1861        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1862    
1863    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1864        caused an overrun.
1865    
1866    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1867        something other than just ASCII characters) inside a group that had an
1868        unlimited repeat caused a loop at compile time (while checking to see
1869        whether the group could match an empty string).
1870    
1871    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1872        [\P{Any}] did so. (Error in the code for printing property names.)
1873    
1874    21. An orphan \E inside a character class could cause a crash.
1875    
1876    22. A repeated capturing bracket such as (A)? could cause a wild memory
1877        reference during compilation.
1878    
1879    23. There are several functions in pcre_compile() that scan along a compiled
1880        expression for various reasons (e.g. to see if it's fixed length for look
1881        behind). There were bugs in these functions when a repeated \p or \P was
1882        present in the pattern. These operators have additional parameters compared
1883        with \d, etc, and these were not being taken into account when moving along
1884        the compiled data. Specifically:
1885    
1886        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1887            length.
1888    
1889        (b) An item such as \pL+ within a repeated group could cause crashes or
1890            loops.
1891    
1892        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1893            "reference to non-existent subpattern" error.
1894    
1895        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1896    
1897    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1898        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1899    
1900    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1901    
1902    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1903        character were causing crashes (broken optimization).
1904    
1905    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1906        \p or \P) caused a compile-time loop.
1907    
1908    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1909        break. For example, the unstudied pattern [\r\n]A does not match the string
1910        "\r\nA" because change 7.0/46 below moves the current point on by two
1911        characters after failing to match at the start. However, the pattern \nA
1912        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1913        the same is true. There doesn't seem any very clean way out of this, but
1914        what I have chosen to do makes the common cases work: PCRE now takes note
1915        of whether there can be an explicit match for \r or \n anywhere in the
1916        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1917        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1918        pattern has explicit CR or LF references.
1919    
1920    29. Added (*CR) etc for changing newline setting at start of pattern.
1921    
1922    
1923    Version 7.2 19-Jun-07
1924    ---------------------
1925    
1926     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1927        which is apparently normally available under Windows.
1928    
1929     2. Re-jig the pcregrep tests with different newline settings in an attempt
1930        to make them independent of the local environment's newline setting.
1931    
1932     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1933    
1934     4. Some of the "internals" tests were previously cut out when the link size
1935        was not 2, because the output contained actual offsets. The recent new
1936        "Z" feature of pcretest means that these can be cut out, making the tests
1937        usable with all link sizes.
1938    
1939     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1940        stack recursion. This gives a massive performance boost under BSD, but just
1941        a small improvement under Linux. However, it saves one field in the frame
1942        in all cases.
1943    
1944     6. Added more features from the forthcoming Perl 5.10:
1945    
1946        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1947            recursion call. It refers to the nth most recently opened parentheses.
1948    
1949        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1950            to be opened parentheses.
1951    
1952        (c) Conditions that refer to capturing parentheses can be specified
1953            relatively, for example, (?(-2)... or (?(+3)...
1954    
1955        (d) \K resets the start of the current match so that everything before
1956            is not part of it.
1957    
1958        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1959    
1960        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1961            reference syntax.
1962    
1963        (g) (?| introduces a group in which the numbering of parentheses in each
1964            alternative starts with the same number.
1965    
1966        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1967    
1968     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1969        PCRE_INFO_JCHANGED.
1970    
1971     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1972        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1973        for detecting groups that can match an empty string.
1974    
1975     9. A pattern with a very large number of alternatives (more than several
1976        hundred) was running out of internal workspace during the pre-compile
1977        phase, where pcre_compile() figures out how much memory will be needed. A
1978        bit of new cunning has reduced the workspace needed for groups with
1979        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1980        workspace instead of running out of the 4096 that are available.
1981    
1982    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1983    
1984    11. Applied patch from Google to remove an optimization that didn't quite work.
1985        The report of the bug said:
1986    
1987          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1988          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1989          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1990    
1991    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1992        it matched the wrong number of bytes.
1993    
1994    
1995    Version 7.1 24-Apr-07
1996    ---------------------
1997    
1998     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1999        that is more "standard", making use of automake and other Autotools. There
2000        is some re-arrangement of the files and adjustment of comments consequent
2001        on this.
2002    
2003     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
2004        for recursive directory scanning broke on some systems because the files
2005        are not scanned in any specific order and on different systems the order
2006        was different. A call to "sort" has been inserted into RunGrepTest for the
2007        approprate test as a short-term fix. In the longer term there may be an
2008        alternative.
2009    
2010     3. I had an email from Eric Raymond about problems translating some of PCRE's
2011        man pages to HTML (despite the fact that I distribute HTML pages, some
2012        people do their own conversions for various reasons). The problems
2013        concerned the use of low-level troff macros .br and .in. I have therefore
2014        removed all such uses from the man pages (some were redundant, some could
2015        be replaced by .nf/.fi pairs). The 132html script that I use to generate
2016        HTML has been updated to handle .nf/.fi and to complain if it encounters
2017        .br or .in.
2018    
2019     4. Updated comments in configure.ac that get placed in config.h.in and also
2020        arranged for config.h to be included in the distribution, with the name
2021        config.h.generic, for the benefit of those who have to compile without
2022        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
2023    
2024     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
2025        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
2026        makevp.bat for the current PCRE, using the additional files
2027        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
2028    
2029     6. A Windows user reported a minor discrepancy with test 2, which turned out
2030        to be caused by a trailing space on an input line that had got lost in his
2031        copy. The trailing space was an accident, so I've just removed it.
2032    
2033     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
2034        that is needed.
2035    
2036     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
2037        as "const" (a) because they are and (b) because it helps the PHP
2038        maintainers who have recently made a script to detect big data structures
2039        in the php code that should be moved to the .rodata section. I remembered
2040        to update Builducptable as well, so it won't revert if ucptable.h is ever
2041        re-created.
2042    
2043     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
2044        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
2045        order to be able to cut out the UTF-8 tables in the latter when UTF-8
2046        support is not required. This saves 1.5-2K of code, which is important in
2047        some applications.
2048    
2049        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
2050        so as not to refer to the tables, even though these functions will never be
2051        called when UTF-8 support is disabled. Otherwise there are problems with a
2052        shared library.
2053    
2054    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
2055    
2056        (a) It was defining its arguments as char * instead of void *.
2057    
2058        (b) It was assuming that all moves were upwards in memory; this was true
2059            a long time ago when I wrote it, but is no longer the case.
2060    
2061        The emulated memove() is provided for those environments that have neither
2062        memmove() nor bcopy(). I didn't think anyone used it these days, but that
2063        is clearly not the case, as these two bugs were recently reported.
2064    
2065    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
2066        and Detrail to create the HTML documentation, the .txt form of the man
2067        pages, and it removes trailing spaces from listed files. It also creates
2068        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
2069        case, it wraps all the #defines with #ifndefs. This script should be run
2070        before "make dist".
2071    
2072    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
2073        with Unicode property support.
2074    
2075        (a) For a maximizing quantifier, if the two different cases of the
2076            character were of different lengths in their UTF-8 codings (there are
2077            some cases like this - I found 11), and the matching function had to
2078            back up over a mixture of the two cases, it incorrectly assumed they
2079            were both the same length.
2080    
2081        (b) When PCRE was configured to use the heap rather than the stack for
2082            recursion during matching, it was not correctly preserving the data for
2083            the other case of a UTF-8 character when checking ahead for a match
2084            while processing a minimizing repeat. If the check also involved
2085            matching a wide character, but failed, corruption could cause an
2086            erroneous result when trying to check for a repeat of the original
2087            character.
2088    
2089    13. Some tidying changes to the testing mechanism:
2090    
2091        (a) The RunTest script now detects the internal link size and whether there
2092            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
2093            values substituted by "configure". (The RunGrepTest script already did
2094            this for UTF-8.) The configure.ac script no longer substitutes the
2095            relevant variables.
2096    
2097        (b) The debugging options /B and /D in pcretest show the compiled bytecode
2098            with length and offset values. This means that the output is different
2099            for different internal link sizes. Test 2 is skipped for link sizes
2100            other than 2 because of this, bypassing the problem. Unfortunately,
2101            there was also a test in test 3 (the locale tests) that used /B and
2102            failed for link sizes other than 2. Rather than cut the whole test out,
2103            I have added a new /Z option to pcretest that replaces the length and
2104            offset values with spaces. This is now used to make test 3 independent
2105            of link size. (Test 2 will be tidied up later.)
2106    
2107    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2108        segmentation fault instead of returning the appropriate error message.
2109    
2110    15. In multiline mode when the newline sequence was set to "any", the pattern
2111        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2112        This doesn't seem right; it now treats the CRLF combination as the line
2113        ending, and so does not match in that case. It's only a pattern such as ^$
2114        that would hit this one: something like ^ABC$ would have failed after \r
2115        and then tried again after \r\n.
2116    
2117    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2118        in an attempt to make files that differ only in their line terminators
2119        compare equal. This works on Linux.
2120    
2121    17. Under certain error circumstances pcregrep might try to free random memory
2122        as it exited. This is now fixed, thanks to valgrind.
2123    
2124    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2125        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2126        was because its rules for how to advance for /g after matching an empty
2127        string at the end of a line did not allow for this case. They now check for
2128        it specially.
2129    
2130    20. pcretest is supposed to handle patterns and data of any length, by
2131        extending its buffers when necessary. It was getting this wrong when the
2132        buffer for a data line had to be extended.
2133    
2134    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2135        CRLF as a newline sequence.
2136    
2137    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2138        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2139        I have nevertheless tidied it up.
2140    
2141    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2142    
2143    24. Added a man page for pcre-config.
2144    
2145    
2146    Version 7.0 19-Dec-06
2147    ---------------------
2148    
2149     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2150        moving to gcc 4.1.1.
2151    
2152     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2153        sys/time.h, which is documented as needed for this function. It doesn't
2154        seem to matter on Linux, but it showed up on some releases of OS X.
2155    
2156     3. It seems that there are systems where bytes whose values are greater than
2157        127 match isprint() in the "C" locale. The "C" locale should be the
2158        default when a C program starts up. In most systems, only ASCII printing
2159        characters match isprint(). This difference caused the output from pcretest
2160        to vary, making some of the tests fail. I have changed pcretest so that:
2161    
2162        (a) When it is outputting text in the compiled version of a pattern, bytes
2163            other than 32-126 are always shown as hex escapes.
2164    
2165        (b) When it is outputting text that is a matched part of a subject string,
2166            it does the same, unless a different locale has been set for the match
2167            (using the /L modifier). In this case, it uses isprint() to decide.
2168    
2169     4. Fixed a major bug that caused incorrect computation of the amount of memory
2170        required for a compiled pattern when options that changed within the
2171        pattern affected the logic of the preliminary scan that determines the
2172        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2173        that the computed length was too small. The symptoms of this bug were
2174        either the PCRE error "internal error: code overflow" from pcre_compile(),
2175        or a glibc crash with a message such as "pcretest: free(): invalid next
2176        size (fast)". Examples of patterns that provoked this bug (shown in
2177        pcretest format) are:
2178    
2179          /(?-x: )/x
2180          /(?x)(?-x: \s*#\s*)/
2181          /((?i)[\x{c0}])/8
2182          /(?i:[\x{c0}])/8
2183    
2184        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2185        is now done differently.
2186    
2187     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2188        wrapper classes; (b) implement a new function in the C++ scanner that is
2189        more efficient than the old way of doing things because it avoids levels of
2190        recursion in the regex matching; (c) add a paragraph to the documentation
2191        for the FullMatch() function.
2192    
2193     6. The escape sequence \n was being treated as whatever was defined as
2194        "newline". Not only was this contrary to the documentation, which states
2195        that \n is character 10 (hex 0A), but it also went horribly wrong when
2196        "newline" was defined as CRLF. This has been fixed.
2197    
2198     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2199        was being set to -1 for the "end of line" case (supposedly a value that no
2200        character can have). Though this value is never used (the check for end of
2201        line is "zero bytes in current character"), it caused compiler complaints.
2202        I've changed it to 0xffffffff.
2203    
2204     8. In pcre_version.c, the version string was being built by a sequence of
2205        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2206        string (as it is for production releases) called a macro with an empty
2207        argument. The C standard says the result of this is undefined. The gcc
2208        compiler treats it as an empty string (which was what was wanted) but it is
2209        reported that Visual C gives an error. The source has been hacked around to
2210        avoid this problem.
2211    
2212     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2213        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2214        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2215        of them did).
2216    
2217    10. Originally, pcretest opened its input and output without "b"; then I was
2218        told that "b" was needed in some environments, so it was added for release
2219        5.0 to both the input and output. (It makes no difference on Unix-like
2220        systems.) Later I was told that it is wrong for the input on Windows. I've
2221        now abstracted the modes into two macros, to make it easier to fiddle with
2222        them, and removed "b" from the input mode under Windows.
2223    
2224    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2225    
2226    12. Added -help and --help to pcretest as an official way of being reminded
2227        of the options.
2228    
2229    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2230        and pcrecpp.cc because they annoy compilers at high warning levels.
2231    
2232    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2233    
2234    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2235        scripts are not C programs :-) and which was not noticed because it works
2236        on Linux.
2237    
2238    16. pcretest is supposed to handle any length of pattern and data line (as one
2239        line or as a continued sequence of lines) by extending its input buffer if
2240        necessary. This feature was broken for very long pattern lines, leading to
2241        a string of junk being passed to pcre_compile() if the pattern was longer
2242        than about 50K.
2243    
2244    17. I have done a major re-factoring of the way pcre_compile() computes the
2245        amount of memory needed for a compiled pattern. Previously, there was code
2246        that made a preliminary scan of the pattern in order to do this. That was
2247        OK when PCRE was new, but as the facilities have expanded, it has become
2248        harder and harder to keep it in step with the real compile phase, and there
2249        have been a number of bugs (see for example, 4 above). I have now found a
2250        cunning way of running the real compile function in a "fake" mode that
2251        enables it to compute how much memory it would need, while actually only
2252        ever using a few hundred bytes of working memory and without too many
2253        tests of the mode. This should make future maintenance and development
2254        easier. A side effect of this work is that the limit of 200 on the nesting
2255        depth of parentheses has been removed (though this was never a serious
2256        limitation, I suspect). However, there is a downside: pcre_compile() now
2257        runs more slowly than before (30% or more, depending on the pattern). I
2258        hope this isn't a big issue. There is no effect on runtime performance.
2259    
2260    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2261        newline (only possible for the last line of a file) and it was a
2262        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2263    
2264    19. Added additional timing features to pcretest. (1) The -tm option now times
2265        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2266        separate command line item, by a number that specifies the number of
2267        repeats to use when timing. The default is 50000; this gives better
2268        precision, but takes uncomfortably long for very large patterns.
2269    
2270    20. Extended pcre_study() to be more clever in cases where a branch of a
2271        subpattern has no definite first character. For example, (a*|b*)[cd] would
2272        previously give no result from pcre_study(). Now it recognizes that the
2273        first character must be a, b, c, or d.
2274    
2275    21. There was an incorrect error "recursive call could loop indefinitely" if
2276        a subpattern (or the entire pattern) that was being tested for matching an
2277        empty string contained only one non-empty item after a nested subpattern.
2278        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2279        incorrectly, because the \d was being skipped in the check.
2280    
2281    22. The pcretest program now has a new pattern option /B and a command line
2282        option -b, which is equivalent to adding /B to every pattern. This causes
2283        it to show the compiled bytecode, without the additional information that
2284        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2285        is the same as /B/I).
2286    
2287    23. A new optimization is now able automatically to treat some sequences such
2288        as a*b as a*+b. More specifically, if something simple (such as a character
2289        or a simple class like \d) has an unlimited quantifier, and is followed by
2290        something that cannot possibly match the quantified thing, the quantifier
2291        is automatically "possessified".
2292    
2293    24. A recursive reference to a subpattern whose number was greater than 39
2294        went wrong under certain circumstances in UTF-8 mode. This bug could also
2295        have affected the operation of pcre_study().
2296    
2297    25. Realized that a little bit of performance could be had by replacing
2298        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2299    
2300    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2301    
2302    27. Possessive quantifiers such as a++ were previously implemented by turning
2303        them into atomic groups such as ($>a+). Now they have their own opcodes,
2304        which improves performance. This includes the automatically created ones
2305        from 23 above.
2306    
2307    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2308        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2309        the first matched character to be a colon. This applied both to named and
2310        numbered groups.
2311    
2312    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2313    
2314    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2315        building PCRE on Windows easier, so I have included it in the distribution.
2316    
2317    31. There is now a check in pcretest against a ridiculously large number being
2318        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2319        loop, the loop is abandoned.
2320    
2321    32. Forward references to subpatterns in conditions such as (?(2)...) where
2322        subpattern 2 is defined later cause pcre_compile() to search forwards in
2323        the pattern for the relevant set of parentheses. This search went wrong
2324        when there were unescaped parentheses in a character class, parentheses
2325        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2326    
2327    33. "Subroutine" calls and backreferences were previously restricted to
2328        referencing subpatterns earlier in the regex. This restriction has now
2329        been removed.
2330    
2331    34. Added a number of extra features that are going to be in Perl 5.10. On the
2332        whole, these are just syntactic alternatives for features that PCRE had
2333        previously implemented using the Python syntax or my own invention. The
2334        other formats are all retained for compatibility.
2335    
2336        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2337            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2338            also .NET compatible.
2339    
2340        (b) A recursion or subroutine call to a named group can now be defined as
2341            (?&name) as well as (?P>name).
2342    
2343        (c) A backreference to a named group can now be defined as \k<name> or
2344            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2345            5.10, are also .NET compatible.
2346    
2347        (d) A conditional reference to a named group can now use the syntax
2348            (?(<name>) or (?('name') as well as (?(name).
2349    
2350        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2351            groups (named and numbered) that are never evaluated inline, but can be
2352            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2353            is always false. There may be only one alternative in such a group.
2354    
2355        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2356            as the simple (?(R). The condition is true only if the most recent
2357            recursion is that of the given number or name. It does not search out
2358            through the entire recursion stack.
2359    
2360        (g) The escape \gN or \g{N} has been added, where N is a positive or
2361            negative number, specifying an absolute or relative reference.
2362    
2363    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2364        some "unreachable code" warnings.
2365    
2366    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2367        things, this adds five new scripts.
2368    
2369    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2370        There were also incompatibilities regarding the handling of \Q..\E inside
2371        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2372        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2373    
2374    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2375        matches an empty string, and forcibly breaks the loop. There were bugs in
2376        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2377        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2378        separate and independent bugs (that affected different cases) have been
2379        fixed.
2380    
2381    39. Refactored the code to abolish the use of different opcodes for small
2382        capturing bracket numbers. This is a tidy that I avoided doing when I
2383        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2384        The new approach is not only tidier, it makes it possible to reduce the
2385        memory needed to fix the previous bug (38).
2386    
2387    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2388        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2389        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2390        mode.
2391    
2392    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2393        report.
2394    
2395    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2396        copy construction and assignment in the C++ wrapper.
2397    
2398    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2399        couple of bugs that could have given wrong results in the "--newline=crlf"
2400        case.
2401    
2402    44. Added a number of casts and did some reorganization of signed/unsigned int
2403        variables following suggestions from Dair Grant. Also renamed the variable
2404        "this" as "item" because it is a C++ keyword.
2405    
2406    45. Arranged for dftables to add
2407    
2408          #include "pcre_internal.h"
2409    
2410        to pcre_chartables.c because without it, gcc 4.x may remove the array
2411        definition from the final binary if PCRE is built into a static library and
2412        dead code stripping is activated.
2413    
2414    46. For an unanchored pattern, if a match attempt fails at the start of a
2415        newline sequence, and the newline setting is CRLF or ANY, and the next two
2416        characters are CRLF, advance by two characters instead of one.
2417    
2418    
2419    Version 6.7 04-Jul-06
2420    ---------------------
2421    
2422     1. In order to handle tests when input lines are enormously long, pcretest has
2423        been re-factored so that it automatically extends its buffers when
2424        necessary. The code is crude, but this _is_ just a test program. The
2425        default size has been increased from 32K to 50K.
2426    
2427     2. The code in pcre_study() was using the value of the re argument before
2428        testing it for NULL. (Of course, in any sensible call of the function, it
2429        won't be NULL.)
2430    
2431     3. The memmove() emulation function in pcre_internal.h, which is used on
2432        systems that lack both memmove() and bcopy() - that is, hardly ever -
2433        was missing a "static" storage class specifier.
2434    
2435     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2436        containing an extended class (one that cannot be represented by a bitmap
2437        because it contains high-valued characters or Unicode property items, e.g.
2438        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2439        pattern, but PCRE should not loop if you do not (it no longer does).
2440        [Detail: two cases were found: (a) a repeated subpattern containing an
2441        extended class; (b) a recursive reference to a subpattern that followed a
2442        previous extended class. It wasn't skipping over the extended class
2443        correctly when UTF-8 mode was not set.]
2444    
2445     5. A negated single-character class was not being recognized as fixed-length
2446        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2447        compile error "lookbehind assertion is not fixed length".
2448    
2449     6. The RunPerlTest auxiliary script was showing an unexpected difference
2450        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2451        write a Perl script that can interpret lines of an input file either as
2452        byte characters or as UTF-8, which is what "perltest" was being required to
2453        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2454        can't do is switch easily at run time between having the "use utf8;" pragma
2455        or not. In the end, I fudged it by using the RunPerlTest script to insert
2456        "use utf8;" explicitly for the UTF-8 tests.
2457    
2458     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2459        the end of the subject string, contrary to the documentation and to what
2460        Perl does. This was true of both matching functions. Now it matches only at
2461        the start of the subject and immediately after *internal* newlines.
2462    
2463     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2464        a pointer to an int instead of a pointer to an unsigned long int. This
2465        caused problems on 64-bit systems.
2466    
2467     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2468        instance of the 'standard' template library not being so standard".
2469    
2470    10. There was no check on the number of named subpatterns nor the maximum
2471        length of a subpattern name. The product of these values is used to compute
2472        the size of the memory block for a compiled pattern. By supplying a very
2473        long subpattern name and a large number of named subpatterns, the size
2474        computation could be caused to overflow. This is now prevented by limiting
2475        the length of names to 32 characters, and the number of named subpatterns
2476        to 10,000.
2477    
2478    11. Subpatterns that are repeated with specific counts have to be replicated in
2479        the compiled pattern. The size of memory for this was computed from the
2480        length of the subpattern and the repeat count. The latter is limited to
2481        65535, but there was no limit on the former, meaning that integer overflow
2482        could in principle occur. The compiled length of a repeated subpattern is
2483        now limited to 30,000 bytes in order to prevent this.
2484    
2485    12. Added the optional facility to have named substrings with the same name.
2486    
2487    13. Added the ability to use a named substring as a condition, using the
2488        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2489        are numbers (not recommended). Forward references are permitted.
2490    
2491    14. Added forward references in named backreferences (if you see what I mean).
2492    
2493    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2494        pattern could run off the end of the subject. For example, the pattern
2495        "(?s)(.{1,5})"8 did this with the subject "ab".
2496    
2497    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2498        PCRE_CASELESS was set when matching characters that were quantified with ?
2499        or *.
2500    
2501    17. A character class other than a single negated character that had a minimum
2502        but no maximum quantifier - for example [ab]{6,} - was not handled
2503        correctly by pce_dfa_exec(). It would match only one character.
2504    
2505    18. A valid (though odd) pattern that looked like a POSIX character
2506        class but used an invalid character after [ (for example [[,abc,]]) caused
2507        pcre_compile() to give the error "Failed: internal error: code overflow" or
2508        in some cases to crash with a glibc free() error. This could even happen if
2509        the pattern terminated after [[ but there just happened to be a sequence of
2510        letters, a binary zero, and a closing ] in the memory that followed.
2511    
2512    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2513        over the years. Originally (before any Unicode support), just the bottom 8
2514        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2515        output from "man perlunicode" includes this:
2516    
2517          The regular expression compiler produces polymorphic opcodes.  That
2518          is, the pattern adapts to the data and automatically switches to
2519          the Unicode character scheme when presented with Unicode data--or
2520          instead uses a traditional byte scheme when presented with byte
2521          data.
2522    
2523        Sadly, a wide octal escape does not cause a switch, and in a string with
2524        no other multibyte characters, these octal escapes are treated as before.
2525        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2526        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2527        Unicode string.
2528    
2529        I have not perpetrated such confusion in PCRE. Up till now, it took just
2530        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2531        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2532        translate to the appropriate multibyte character.
2533    
2534    29. Applied some refactoring to reduce the number of warnings from Microsoft
2535        and Borland compilers. This has included removing the fudge introduced
2536        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2537        a warning about an unused variable.
2538    
2539    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2540        characters since release 4.0, because Perl (from release 5.004) does not.
2541        [Or at least, is documented not to: some releases seem to be in conflict
2542        with the documentation.] However, when a pattern was studied with
2543        pcre_study() and all its branches started with \s, PCRE still included VT
2544        as a possible starting character. Of course, this did no harm; it just
2545        caused an unnecessary match attempt.
2546    
2547    22. Removed a now-redundant internal flag bit that recorded the fact that case
2548        dependency changed within the pattern. This was once needed for "required
2549        byte" processing, but is no longer used. This recovers a now-scarce options
2550        bit. Also moved the least significant internal flag bit to the most-
2551        significant bit of the word, which was not previously used (hangover from
2552        the days when it was an int rather than a uint) to free up another bit for
2553        the future.
2554    
2555    23. Added support for CRLF line endings as well as CR and LF. As well as the
2556        default being selectable at build time, it can now be changed at runtime
2557        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2558        specify that it is scanning data with non-default line endings.
2559    
2560    24. Changed the definition of CXXLINK to make it agree with the definition of
2561        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2562    
2563    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2564        recursions. This makes a big different to stack usage for some patterns.
2565    
2566    26. If a subpattern containing a named recursion or subroutine reference such
2567        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2568        the space required for the compiled pattern went wrong and gave too small a
2569        value. Depending on the environment, this could lead to "Failed: internal
2570        error: code overflow at offset 49" or "glibc detected double free or
2571        corruption" errors.
2572    
2573    27. Applied patches from Google (a) to support the new newline modes and (b) to
2574        advance over multibyte UTF-8 characters in GlobalReplace.
2575    
2576    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2577        difference for some implementation of PCRE in some Windows version.
2578    
2579    29. Added some extra testing facilities to pcretest:
2580    
2581        \q<number>   in a data line sets the "match limit" value
2582        \Q<number>   in a data line sets the "match recursion limt" value
2583        -S <number>  sets the stack size, where <number> is in megabytes
2584    
2585        The -S option isn't available for Windows.
2586    
2587    
2588    Version 6.6 06-Feb-06
2589    ---------------------
2590    
2591     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2592        in pcreposix.h. I have copied the definition from pcre.h.
2593    
2594     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2595        because pcre.h is no longer a built file.
2596    
2597     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2598        not normally included in the compiled code.
2599    
2600    
2601    Version 6.5 01-Feb-06
2602    ---------------------
2603    
2604     1. When using the partial match feature with pcre_dfa_exec(), it was not
2605        anchoring the second and subsequent partial matches at the new starting
2606        point. This could lead to incorrect results. For example, with the pattern
2607        /1234/, partially matching against "123" and then "a4" gave a match.
2608    
2609     2. Changes to pcregrep:
2610    
2611        (a) All non-match returns from pcre_exec() were being treated as failures
2612            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2613            error message is output. Some extra information is given for the
2614            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2615            probably the only errors that are likely to be caused by users (by
2616            specifying a regex that has nested indefinite repeats, for instance).
2617            If there are more than 20 of these errors, pcregrep is abandoned.
2618    
2619        (b) A binary zero was treated as data while matching, but terminated the
2620            output line if it was written out. This has been fixed: binary zeroes
2621            are now no different to any other data bytes.
2622    
2623        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2624            used to set a locale for matching. The --locale=xxxx long option has
2625            been added (no short equivalent) to specify a locale explicitly on the
2626            pcregrep command, overriding the environment variables.
2627    
2628        (d) When -B was used with -n, some line numbers in the output were one less
2629            than they should have been.
2630    
2631        (e) Added the -o (--only-matching) option.
2632    
2633        (f) If -A or -C was used with -c (count only), some lines of context were
2634            accidentally printed for the final match.
2635    
2636        (g) Added the -H (--with-filename) option.
2637    
2638        (h) The combination of options -rh failed to suppress file names for files
2639            that were found from directory arguments.
2640    
2641        (i) Added the -D (--devices) and -d (--directories) options.
2642    
2643        (j) Added the -F (--fixed-strings) option.
2644    
2645        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2646    
2647        (l) Added the --colo(u)r option.
2648    
2649        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2650            is not present by default.
2651    
2652     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2653        items such as (?R) or (?1), when the recursion could match a number of
2654        alternatives. If it matched one of the alternatives, but subsequently,
2655        outside the recursion, there was a failure, the code tried to back up into
2656        the recursion. However, because of the way PCRE is implemented, this is not
2657        possible, and the result was an incorrect result from the match.
2658    
2659        In order to prevent this happening, the specification of recursion has
2660        been changed so that all such subpatterns are automatically treated as
2661        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2662    
2663     4. I had overlooked the fact that, in some locales, there are characters for
2664        which isalpha() is true but neither isupper() nor islower() are true. In
2665        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2666        and ordfeminine) are like this. This affected the treatment of \w and \W
2667        when they appeared in character classes, but not when they appeared outside
2668        a character class. The bit map for "word" characters is now created
2669        separately from the results of isalnum() instead of just taking it from the
2670        upper, lower, and digit maps. (Plus the underscore character, of course.)
2671    
2672     5. The above bug also affected the handling of POSIX character classes such as
2673        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2674        permanent tables. Instead, the bit maps for such a class were previously
2675        created as the appropriate unions of the upper, lower, and digit bitmaps.
2676        Now they are created by subtraction from the [[:word:]] class, which has
2677        its own bitmap.
2678    
2679     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2680        It is created by subtracting the vertical space characters (\x09, \x0a,
2681        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2682        subtraction was done in the overall bitmap for a character class, meaning
2683        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2684        be recognized. This bug has been fixed.
2685    
2686     7. Patches from the folks at Google:
2687    
2688          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2689          real life, but is still worth protecting against".
2690    
2691          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2692          regular expressions".
2693    
2694          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2695          have it.
2696    
2697          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2698          "configure" and the latter not, in order to fix a problem somebody had
2699          with compiling the Arg class on HP-UX.
2700    
2701          (e) Improve the error-handling of the C++ wrapper a little bit.
2702    
2703          (f) New tests for checking recursion limiting.
2704    
2705     8. The pcre_memmove() function, which is used only if the environment does not
2706        have a standard memmove() function (and is therefore rarely compiled),
2707        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2708        returning a result (though PCRE never actually uses the result).
2709    
2710     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2711        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2712        returned instead of calling malloc() with an overflowing number that would
2713        most likely cause subsequent chaos.
2714    
2715    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2716    
2717    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2718        with this option is matched, the nmatch and pmatch options of regexec() are
2719        ignored.
2720    
2721    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2722        provided in case anyone wants to the the POSIX interface with UTF-8
2723        strings.
2724    
2725    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2726        C++ linking (needed for some HP-UX environments).
2727    
2728    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2729        (unused parameter) and in the pcre_printint() function (omitted "default"
2730        switch label when the default is to do nothing).
2731    
2732    15. Added some code to make it possible, when PCRE is compiled as a C++
2733        library, to replace subject pointers for pcre_exec() with a smart pointer
2734        class, thus making it possible to process discontinuous strings.
2735    
2736    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2737        much the same function. They were added by different people who were trying
2738        to make PCRE easy to compile on non-Unix systems. It has been suggested
2739        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2740        for compiling on Windows systems. I have therefore replaced it with
2741        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2742        defaults to "extern" for C or "extern C" for C++, which works fine on
2743        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2744        SCOPE with something explicit in config.h. In addition:
2745    
2746        (a) pcreposix.h still had just "extern" instead of either of these macros;
2747            I have replaced it with PCRE_DATA_SCOPE.
2748    
2749        (b) Functions such as _pcre_xclass(), which are internal to the library,
2750            but external in the C sense, all had PCRE_EXPORT in their definitions.
2751            This is apparently wrong for the Windows case, so I have removed it.
2752            (It makes no difference on Unix-like systems.)
2753    
2754    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2755        of recursive calls to match(). This is different to MATCH_LIMIT because
2756        that limits the total number of calls to match(), not all of which increase
2757        the depth of recursion. Limiting the recursion depth limits the amount of
2758        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2759        when PCRE is compiled, and changed at run time. A patch from Google adds
2760        this functionality to the C++ interface.
2761    
2762    18. Changes to the handling of Unicode character properties:
2763    
2764        (a) Updated the table to Unicode 4.1.0.
2765    
2766        (b) Recognize characters that are not in the table as "Cn" (undefined).
2767    
2768        (c) I revised the way the table is implemented to a much improved format
2769            which includes recognition of ranges. It now supports the ranges that
2770            are defined in UnicodeData.txt, and it also amalgamates other
2771            characters into ranges. This has reduced the number of entries in the
2772            table from around 16,000 to around 3,000, thus reducing its size
2773            considerably. I realized I did not need to use a tree structure after
2774            all - a binary chop search is just as efficient. Having reduced the
2775            number of entries, I extended their size from 6 bytes to 8 bytes to
2776            allow for more data.
2777    
2778        (d) Added support for Unicode script names via properties such as \p{Han}.
2779    
2780    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2781        matching that character.
2782    
2783    20. When matching a repeated Unicode property with a minimum greater than zero,
2784        (for example \pL{2,}), PCRE could look past the end of the subject if it
2785        reached it while seeking the minimum number of characters. This could
2786        happen only if some of the characters were more than one byte long, because
2787        there is a check for at least the minimum number of bytes.
2788    
2789    21. Refactored the implementation of \p and \P so as to be more general, to
2790        allow for more different types of property in future. This has changed the
2791        compiled form incompatibly. Anybody with saved compiled patterns that use
2792        \p or \P will have to recompile them.
2793    
2794    22. Added "Any" and "L&" to the supported property types.
2795    
2796    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2797        but give a compile time error if the value is greater than 0xff.
2798    
2799    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2800        accidentally not being installed or uninstalled.
2801    
2802    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2803        made were to insert the current release number. This seemed silly, because
2804        it made things harder for people building PCRE on systems that don't run
2805        "configure". I have turned pcre.h into a distributed file, no longer built
2806        by "configure", with the version identification directly included. There is
2807        no longer a pcre.h.in file.
2808    
2809        However, this change necessitated a change to the pcre-config script as
2810        well. It is built from pcre-config.in, and one of the substitutions was the
2811        release number. I have updated configure.ac so that ./configure now finds
2812        the release number by grepping pcre.h.
2813    
2814    26. Added the ability to run the tests under valgrind.
2815    
2816    
2817    Version 6.4 05-Sep-05
2818    ---------------------
2819    
2820     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2821        "--" to be printed when multiple files were scanned, even when none of the
2822        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2823        consider it to be a bug, and have restored the previous behaviour.
2824    
2825     2. A couple of code tidies to get rid of compiler warnings.
2826    
2827     3. The pcretest program used to cheat by referring to symbols in the library
2828        whose names begin with _pcre_. These are internal symbols that are not
2829        really supposed to be visible externally, and in some environments it is
2830        possible to suppress them. The cheating is now confined to including
2831        certain files from the library's source, which is a bit cleaner.
2832    
2833     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2834        file's purpose clearer.
2835    
2836     5. Reorganized pcre_ucp_findchar().
2837    
2838    
2839    Version 6.3 15-Aug-05
2840    ---------------------
2841    
2842     1. The file libpcre.pc.in did not have general read permission in the tarball.
2843    
2844     2. There were some problems when building without C++ support:
2845    
2846        (a) If C++ support was not built, "make install" and "make test" still
2847            tried to test it.
2848    
2849        (b) There were problems when the value of CXX was explicitly set. Some
2850            changes have been made to try to fix these, and ...
2851    
2852        (c) --disable-cpp can now be used to explicitly disable C++ support.
2853    
2854        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2855            backslash in a target when C++ was disabled. This confuses some
2856            versions of "make", apparently. Using an intermediate variable solves
2857            this. (Same for CPP_LOBJ.)
2858    
2859     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2860        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2861        necessary on certain architectures.
2862    
2863     4. Added a setting of -export-symbols-regex to the link command to remove
2864        those symbols that are exported in the C sense, but actually are local
2865        within the library, and not documented. Their names all begin with
2866        "_pcre_". This is not a perfect job, because (a) we have to except some
2867        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2868        available (and never for static libraries). I have made a note to try to
2869        find a way round (a) in the future.
2870    
2871    
2872    Version 6.2 01-Aug-05
2873    ---------------------
2874    
2875     1. There was no test for integer overflow of quantifier values. A construction
2876        such as {1111111111111111} would give undefined results. What is worse, if
2877        a minimum quantifier for a parenthesized subpattern overflowed and became
2878        negative, the calculation of the memory size went wrong. This could have
2879        led to memory overwriting.
2880    
2881     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2882    
2883     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2884        operating environments where this matters.
2885    
2886     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2887        PCRE options from within the C++ wrapper.
2888    
2889     5. Named capturing subpatterns were not being correctly counted when a pattern
2890        was compiled. This caused two problems: (a) If there were more than 100
2891        such subpatterns, the calculation of the memory needed for the whole
2892        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2893        back references of the form \12, where the number was greater than 9, were
2894        not recognized as back references, even though there were sufficient
2895        previous subpatterns.
2896    
2897     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2898        versions of gcc, e.g. 2.95.4.
2899    
2900    
2901    Version 6.1 21-Jun-05
2902    ---------------------
2903    
2904     1. There was one reference to the variable "posix" in pcretest.c that was not
2905        surrounded by "#if !defined NOPOSIX".
2906    
2907     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2908        the cross-check on the old pcre_info() function, for the benefit of the
2909        cut-down version of PCRE that is currently imported into Exim.
2910    
2911     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2912        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2913        patterns that start (?i) but I don't think that matters. The use of (?i) is
2914        just an example; this all applies to the other options as well.
2915    
2916     4. Since libtool seems to echo the compile commands it is issuing, the output
2917        from "make" can be reduced a bit by putting "@" in front of each libtool
2918        compile command.
2919    
2920     5. Patch from the folks at Google for configure.in to be a bit more thorough
2921        in checking for a suitable C++ installation before trying to compile the
2922        C++ stuff. This should fix a reported problem when a compiler was present,
2923        but no suitable headers.
2924    
2925     6. The man pages all had just "PCRE" as their title. I have changed them to
2926        be the relevant file name. I have also arranged that these names are
2927        retained in the file doc/pcre.txt, which is a concatenation in text format
2928        of all the man pages except the little individual ones for each function.
2929    
2930     7. The NON-UNIX-USE file had not been updated for the different set of source
2931        files that come with release 6. I also added a few comments about the C++
2932        wrapper.
2933    
2934    
2935    Version 6.0 07-Jun-05
2936    ---------------------
2937    
2938     1. Some minor internal re-organization to help with my DFA experiments.
2939    
2940     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2941        didn't matter for the library itself when fully configured, but did matter
2942        when compiling without UCP support, or within Exim, where the ucp files are
2943        not imported.
2944    
2945     3. Refactoring of the library code to split up the various functions into
2946        different source modules. The addition of the new DFA matching code (see
2947        below) to a single monolithic source would have made it really too
2948        unwieldy, quite apart from causing all the code to be include in a
2949        statically linked application, when only some functions are used. This is
2950        relevant even without the DFA addition now that patterns can be compiled in
2951        one application and matched in another.
2952    
2953        The downside of splitting up is that there have to be some external
2954        functions and data tables that are used internally in different modules of
2955        the library but which are not part of the API. These have all had their
2956        names changed to start with "_pcre_" so that they are unlikely to clash
2957        with other external names.
2958    
2959     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2960        a different (DFA) algorithm. Although it is slower than the original
2961        function, it does have some advantages for certain types of matching
2962        problem.
2963    
2964     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2965        including restarting after a partial match.
2966    
2967     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2968        defined when compiling for Windows was sent to me. I have put it into the
2969        code, though I have no means of testing or verifying it.
2970    
2971     7. Added the pcre_refcount() auxiliary function.
2972    
2973     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2974        match before or at the first newline in the subject string. In pcretest,
2975        the /f option on a pattern can be used to set this.
2976    
2977     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2978        would behave wrongly. This has been present in PCRE since release 4.0.
2979    
2980    10. A number of changes to the pcregrep command:
2981    
2982        (a) Refactored how -x works; insert ^(...)$ instead of setting
2983            PCRE_ANCHORED and checking the length, in preparation for adding
2984            something similar for -w.
2985    
2986        (b) Added the -w (match as a word) option.
2987    
2988        (c) Refactored the way lines are read and buffered so as to have more
2989            than one at a time available.
2990    
2991        (d) Implemented a pcregrep test script.
2992    
2993        (e) Added the -M (multiline match) option. This allows patterns to match
2994            over several lines of the subject. The buffering ensures that at least
2995            8K, or the rest of the document (whichever is the shorter) is available
2996            for matching (and similarly the previous 8K for lookbehind assertions).
2997    
2998        (f) Changed the --help output so that it now says
2999    
3000              -w, --word-regex(p)
3001    
3002            instead of two lines, one with "regex" and the other with "regexp"
3003            because that confused at least one person since the short forms are the
3004            same. (This required a bit of code, as the output is generated
3005            automatically from a table. It wasn't just a text change.)
3006    
3007        (g) -- can be used to terminate pcregrep options if the next thing isn't an
3008            option but starts with a hyphen. Could be a pattern or a path name
3009            starting with a hyphen, for instance.
3010    
3011        (h) "-" can be given as a file name to represent stdin.
3012    
3013        (i) When file names are being printed, "(standard input)" is used for
3014            the standard input, for compatibility with GNU grep. Previously
3015            "<stdin>" was used.
3016    
3017        (j) The option --label=xxx can be used to supply a name to be used for
3018            stdin when file names are being printed. There is no short form.
3019    
3020        (k) Re-factored the options decoding logic because we are going to add
3021            two more options that take data. Such options can now be given in four
3022            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
3023    
3024        (l) Added the -A, -B, and -C options for requesting that lines of context
3025            around matches be printed.
3026    
3027        (m) Added the -L option to print the names of files that do not contain
3028            any matching lines, that is, the complement of -l.
3029    
3030        (n) The return code is 2 if any file cannot be opened, but pcregrep does
3031            continue to scan other files.
3032    
3033        (o) The -s option was incorrectly implemented. For compatibility with other
3034            greps, it now suppresses the error message for a non-existent or non-
3035            accessible file (but not the return code). There is a new option called
3036            -q that suppresses the output of matching lines, which was what -s was
3037            previously doing.
3038    
3039        (p) Added --include and --exclude options to specify files for inclusion
3040            and exclusion when recursing.
3041    
3042    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
3043        Hopefully, it now does.
3044    
3045    12. Missing cast in pcre_study().
3046    
3047    13. Added an "uninstall" target to the makefile.
3048    
3049    14. Replaced "extern" in the function prototypes in Makefile.in with
3050        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
3051        world, but is set differently for Windows.
3052    
3053    15. Added a second compiling function called pcre_compile2(). The only
3054        difference is that it has an extra argument, which is a pointer to an
3055        integer error code. When there is a compile-time failure, this is set
3056        non-zero, in addition to the error test pointer being set to point to an
3057        error message. The new argument may be NULL if no error number is required
3058        (but then you may as well call pcre_compile(), which is now just a
3059        wrapper). This facility is provided because some applications need a
3060        numeric error indication, but it has also enabled me to tidy up the way
3061        compile-time errors are handled in the POSIX wrapper.
3062    
3063    16. Added VPATH=.libs to the makefile; this should help when building with one
3064        prefix path and installing with another. (Or so I'm told by someone who
3065        knows more about this stuff than I do.)
3066    
3067    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
3068        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
3069        match everything, including newlines. This is not POSIX-compatible, but
3070        somebody wanted the feature. From pcretest it can be activated by using
3071        both the P and the s flags.
3072    
3073    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
3074    
3075    19. libpcre.pc was being incorrectly installed as executable.
3076    
3077    20. A couple of places in pcretest check for end-of-line by looking for '\n';
3078        it now also looks for '\r' so that it will work unmodified on Windows.
3079    
3080    21. Added Google's contributed C++ wrapper to the distribution.
3081    
3082    22. Added some untidy missing memory free() calls in pcretest, to keep
3083        Electric Fence happy when testing.
3084    
3085    
3086    
3087    Version 5.0 13-Sep-04
3088    ---------------------
3089    
3090     1. Internal change: literal characters are no longer packed up into items
3091        containing multiple characters in a single byte-string. Each character
3092        is now matched using a separate opcode. However, there may be more than one
3093        byte in the character in UTF-8 mode.
3094    
3095     2. The pcre_callout_block structure has two new fields: pattern_position and
3096        next_item_length. These contain the offset in the pattern to the next match
3097        item, and its length, respectively.
3098    
3099     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
3100        insertion of callouts before each pattern item. Added the /C option to
3101        pcretest to make use of this.
3102    
3103     4. On the advice of a Windows user, the lines
3104    
3105          #if defined(_WIN32) || defined(WIN32)
3106          _setmode( _fileno( stdout ), 0x8000 );
3107          #endif  /* defined(_WIN32) || defined(WIN32) */
3108    
3109        have been added to the source of pcretest. This apparently does useful
3110        magic in relation to line terminators.
3111    
3112     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
3113        for the benefit of those environments where the "b" makes a difference.
3114    
3115     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
3116        to know about it. I have put a hack into configure.in that adds in code
3117        to set GCC=yes if CC=icc. This seems to end up at a point in the
3118        generated configure script that is early enough to affect the setting of
3119        compiler options, which is what is needed, but I have no means of testing
3120        whether it really works. (The user who reported this had patched the
3121        generated configure script, which of course I cannot do.)
3122    
3123        LATER: After change 22 below (new libtool files), the configure script
3124        seems to know about icc (and also ecc). Therefore, I have commented out
3125        this hack in configure.in.
3126    
3127     7. Added support for pkg-config (2 patches were sent in).
3128    
3129     8. Negated POSIX character classes that used a combination of internal tables
3130        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
3131        [[:^ascii]]. Typically, they would match almost any characters. The other
3132        POSIX classes were not broken in this way.
3133    
3134     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
3135        to find the match, as PCRE was deluded into thinking that the match had to
3136        start at the start point or following a newline. The same bug applied to
3137        patterns with negative forward assertions or any backward assertions
3138        preceding ".*" at the start, unless the pattern required a fixed first
3139        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
3140    
3141    10. In UTF-8 mode, when moving forwards in the subject after a failed match
3142        starting at the last subject character, bytes beyond the end of the subject
3143        string were read.
3144    
3145    11. Renamed the variable "class" as "classbits" to make life easier for C++
3146        users. (Previously there was a macro definition, but it apparently wasn't
3147        enough.)
3148    
3149    12. Added the new field "tables" to the extra data so that tables can be passed
3150        in at exec time, or the internal tables can be re-selected. This allows
3151        a compiled regex to be saved and re-used at a later time by a different
3152        program that might have everything at different addresses.
3153    
3154    13. Modified the pcre-config script so that, when run on Solaris, it shows a
3155        -R library as well as a -L library.
3156    
3157    14. The debugging options of pcretest (-d on the command line or D on a
3158        pattern) showed incorrect output for anything following an extended class
3159        that contained multibyte characters and which was followed by a quantifier.
3160    
3161    15. Added optional support for general category Unicode character properties
3162        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
3163        support. It adds about 90K to the size of the library. The meanings of the
3164        inbuilt class escapes such as \d and \s have NOT been changed.
3165    
3166    16. Updated pcredemo.c to include calls to free() to release the memory for the
3167        compiled pattern.
3168    
3169    17. The generated file chartables.c was being created in the source directory
3170        instead of in the building directory. This caused the build to fail if the
3171        source directory was different from the building directory, and was
3172        read-only.
3173    
3174    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
3175        file. No doubt somebody will tell me if they don't make sense... Also added
3176        Dan Mooney's comments about building on OpenVMS.
3177    
3178    19. Added support for partial matching via the PCRE_PARTIAL option for
3179        pcre_exec() and the \P data escape in pcretest.
3180    
3181    20. Extended pcretest with 3 new pattern features:
3182    
3183        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
3184              write the compiled pattern to the file whose name is "rest-of-line".
3185              This is a straight binary dump of the data, with the saved pointer to
3186              the character tables forced to be NULL. The study data, if any, is
3187              written too. After writing, pcretest reads a new pattern.
3188    
3189        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
3190              compiled pattern from the given file. There must not be any
3191              occurrences of "<" in the file name (pretty unlikely); if there are,
3192              pcretest will instead treat the initial "<" as a pattern delimiter.
3193              After reading in the pattern, pcretest goes on to read data lines as
3194              usual.
3195    
3196        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
3197              and 16-bit fields in a compiled pattern, to simulate a pattern that
3198              was compiled on a host of opposite endianness.
3199    
3200    21. The pcre-exec() function can now cope with patterns that were compiled on
3201        hosts of opposite endianness, with this restriction:
3202    
3203          As for any compiled expression that is saved and used later, the tables
3204          pointer field cannot be preserved; the extra_data field in the arguments
3205          to pcre_exec() should be used to pass in a tables address if a value
3206          other than the default internal tables were used at compile time.
3207    
3208    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
3209        now diagnosed as an error. Previously, most of the time, a negative number
3210        would have been treated as zero, but if in addition "ovector" was passed as
3211        NULL, a crash could occur.
3212    
3213    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
3214        new versions from the libtool 1.5 distribution (the last one is a copy of
3215        a file called libtool.m4). This seems to have fixed the need to patch
3216        "configure" to support Darwin 1.3 (which I used to do). However, I still
3217        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
3218        workstation).
3219    
3220    24. Changed the PCRE licence to be the more standard "BSD" licence.
3221    
3222    
3223    Version 4.5 01-Dec-03
3224    ---------------------
3225    
3226     1. There has been some re-arrangement of the code for the match() function so
3227        that it can be compiled in a version that does not call itself recursively.
3228        Instead, it keeps those local variables that need separate instances for
3229        each "recursion" in a frame on the heap, and gets/frees frames whenever it
3230        needs to "recurse". Keeping track of where control must go is done by means
3231        of setjmp/longjmp. The whole thing is implemented by a set of macros that
3232        hide most of the details from the main code, and operates only if
3233        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
3234        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
3235        operating.
3236    
3237        To make it easier for callers to provide specially tailored get/free
3238        functions for this usage, two new functions, pcre_stack_malloc, and
3239        pcre_stack_free, are used. They are always called in strict stacking order,
3240        and the size of block requested is always the same.
3241    
3242        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
3243        PCRE has been compiled to use the stack or the heap for recursion. The
3244        -C option of pcretest uses this to show which version is compiled.
3245    
3246        A new data escape \S, is added to pcretest; it causes the amounts of store
3247        obtained and freed by both kinds of malloc/free at match time to be added
3248        to the output.
3249    
3250     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
3251        what's available on my current Linux desktop machine.
3252    
3253     3. When matching a UTF-8 string, the test for a valid string at the start has
3254        been extended. If start_offset is not zero, PCRE now checks that it points
3255        to a byte that is the start of a UTF-8 character. If not, it returns
3256        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
3257        this is necessary because there may be backward assertions in the pattern.
3258        When matching the same subject several times, it may save resources to use
3259        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
3260    
3261     4. The code for checking the validity of UTF-8 strings has been tightened so
3262        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
3263        containing "overlong sequences".
3264    
3265     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
3266        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
3267        should have been "&", but it just so happened that all the cases this let
3268        through by mistake were picked up later in the function.
3269    
3270     6. I had used a variable called "isblank" - this is a C99 function, causing
3271        some compilers to warn. To avoid this, I renamed it (as "blankclass").
3272    
3273     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
3274        prompting; (b) run "./pcretest /dev/null" at the start of the test script
3275        so the version is shown; (c) stop "make test" echoing "./RunTest".
3276    
3277     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
3278    
3279     9. The prototype for memmove() for systems that don't have it was using
3280        size_t, but the inclusion of the header that defines size_t was later. I've
3281        moved the #includes for the C headers earlier to avoid this.
3282    
3283    10. Added some adjustments to the code to make it easier to compiler on certain
3284        special systems:
3285    
3286          (a) Some "const" qualifiers were missing.
3287          (b) Added the macro EXPORT before all exported functions; by default this
3288              is defined to be empty.
3289          (c) Changed the dftables auxiliary program (that builds chartables.c) so
3290              that it reads its output file name as an argument instead of writing
3291              to the standard output and assuming this can be redirected.
3292    
3293    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
3294        class containing characters with values greater than 255, PCRE compilation
3295        went into a loop.
3296    
3297    12. A recursive reference to a subpattern that was within another subpattern
3298        that had a minimum quantifier of zero caused PCRE to crash. For example,
3299        (x(y(?2))z)? provoked this bug with a subject that got as far as the
3300        recursion. If the recursively-called subpattern itself had a zero repeat,
3301        that was OK.
3302    
3303    13. In pcretest, the buffer for reading a data line was set at 30K, but the
3304        buffer into which it was copied (for escape processing) was still set at
3305        1024, so long lines caused crashes.
3306    
3307    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
3308        "internal error: code overflow...". This applied to any character class
3309        that was followed by a possessive quantifier.
3310    
3311    15. Modified the Makefile to add libpcre.la as a prerequisite for
3312        libpcreposix.la because I was told this is needed for a parallel build to
3313        work.
3314    
3315    16. If a pattern that contained .* following optional items at the start was
3316        studied, the wrong optimizing data was generated, leading to matching
3317        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
3318        matching string must start with a or b or c. The correct conclusion for
3319        this pattern is that a match can start with any character.
3320    
3321    
3322    Version 4.4 13-Aug-03
3323    ---------------------
3324    
3325     1. In UTF-8 mode, a character class containing characters with values between
3326        127 and 255 was not handled correctly if the compiled pattern was studied.
3327        In fixing this, I have also improved the studying algorithm for such
3328        classes (slightly).
3329    
3330     2. Three internal functions had redundant arguments passed to them. Removal
3331        might give a very teeny performance improvement.
3332    
3333     3. Documentation bug: the value of the capture_top field in a callout is *one
3334        more than* the number of the hightest numbered captured substring.
3335    
3336     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
3337        in incorrectly linking with a previously installed version. They now link
3338        explicitly with libpcre.la.
3339    
3340     5. configure.in no longer needs to recognize Cygwin specially.
3341    
3342     6. A problem in pcre.in for Windows platforms is fixed.
3343    
3344     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
3345        pcretest, it used to include the size of the study block as part of its
3346        output. Unfortunately, the structure contains a field that has a different
3347        size on different hardware architectures. This meant that the tests that
3348        showed this size failed. As the block is currently always of a fixed size,
3349        this information isn't actually particularly useful in pcretest output, so
3350        I have just removed it.
3351    
3352     8. Three pre-processor statements accidentally did not start in column 1.
3353        Sadly, there are *still* compilers around that complain, even though
3354        standard C has not required this for well over a decade. Sigh.
3355    
3356     9. In pcretest, the code for checking callouts passed small integers in the
3357        callout_data field, which is a void * field. However, some picky compilers
3358        complained about the casts involved for this on 64-bit systems. Now
3359        pcretest passes the address of the small integer instead, which should get
3360        rid of the warnings.
3361    
3362    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
3363        both compile and run time, and gives an error if an invalid UTF-8 sequence
3364        is found. There is a option for disabling this check in cases where the
3365        string is known to be correct and/or the maximum performance is wanted.
3366    
3367    11. In response to a bug report, I changed one line in Makefile.in from
3368    
3369            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
3370        to
3371            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
3372    
3373        to look similar to other lines, but I have no way of telling whether this
3374        is the right thing to do, as I do not use Windows. No doubt I'll get told
3375        if it's wrong...
3376    
3377    
3378    Version 4.3 21-May-03
3379    ---------------------
3380    
3381    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
3382       Makefile.
3383    
3384    2. Some refactoring to improve the quality of the code:
3385    
3386       (i)   The utf8_table... variables are now declared "const".
3387    
3388       (ii)  The code for \cx, which used the "case flipping" table to upper case
3389             lower case letters, now just substracts 32. This is ASCII-specific,
3390             but the whole concept of \cx is ASCII-specific, so it seems
3391             reasonable.
3392    
3393       (iii) PCRE was using its character types table to recognize decimal and
3394             hexadecimal digits in the pattern. This is silly, because it handles
3395             only 0-9, a-f, and A-F, but the character types table is locale-
3396             specific, which means strange things might happen. A private
3397             table is now used for this - though it costs 256 bytes, a table is
3398             much faster than multiple explicit tests. Of course, the standard
3399             character types table is still used for matching digits in subject
3400             strings against \d.
3401    
3402       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
3403             ending in _t are). So I've renamed it as ESC_tee.
3404    
3405    3. The first argument for regexec() in the POSIX wrapper should have been
3406       defined as "const".
3407    
3408    4. Changed pcretest to use malloc() for its buffers so that they can be
3409       Electric Fenced for debugging.
3410    
3411    5. There were several places in the code where, in UTF-8 mode, PCRE would try
3412       to read one or more bytes before the start of the subject string. Often this
3413       had no effect on PCRE's behaviour, but in some circumstances it could
3414       provoke a segmentation fault.
3415    
3416    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
3417       to try to read one or more bytes before the start of the subject string.
3418    
3419    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
3420       UTF-8 support could misbehave in various ways if the subject string
3421       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
3422       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
3423       back over UTF-8 characters.)
3424    
3425    
3426    Version 4.2 14-Apr-03
3427    ---------------------
3428    
3429    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
3430    
3431    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
3432         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
3433         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
3434         [WIN_PREFIX]: new variable, "cyg" for Cygwin
3435         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
3436           and BUILD_EXEEXT
3437         Note: automatic setting of the BUILD variables is not yet working
3438         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
3439           compile-time but not at link-time
3440         [LINK]: use for linking executables only
3441         make different versions for Windows and non-Windows
3442         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
3443           libraries
3444         [LINK_FOR_BUILD]: new variable
3445         [OBJEXT]: use throughout
3446         [EXEEXT]: use throughout
3447         <winshared>: new target
3448         <wininstall>: new target
3449         <dftables.o>: use native compiler
3450         <dftables>: use native linker
3451         <install>: handle Windows platform correctly
3452         <clean>: ditto
3453         <check>: ditto
3454         copy DLL to top builddir before testing
3455    
3456       As part of these changes, -no-undefined was removed again. This was reported
3457       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
3458       in any case.
3459    
3460    3. Some tidies to get rid of compiler warnings:
3461    
3462       . In the match_data structure, match_limit was an unsigned long int, whereas
3463         match_call_count was an int. I've made them both unsigned long ints.
3464    
3465       . In pcretest the fact that a const uschar * doesn't automatically cast to
3466         a void * provoked a warning.
3467    
3468       . Turning on some more compiler warnings threw up some "shadow" variables
3469         and a few more missing casts.
3470    
3471    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
3472       option, a class that contained a single character with a value between 128
3473       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
3474    
3475    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
3476       option, a class that contained several characters, but with at least one
3477       whose value was between 128 and 255 caused PCRE to crash.
3478    
3479    
3480    Version 4.1 12-Mar-03
3481    ---------------------
3482    
3483    1. Compiling with gcc -pedantic found a couple of places where casts were
3484    needed, and a string in dftables.c that was longer than standard compilers are
3485    required to support.
3486    
3487    2. Compiling with Sun's compiler found a few more places where the code could
3488    be tidied up in order to avoid warnings.
3489    
3490    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
3491    first of these names is deprecated in the latest Autoconf in favour of the name
3492    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
3493    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
3494    analogy I have changed it to CFLAGS_FOR_BUILD.
3495    
3496    4. Added -no-undefined to the linking command in the Makefile, because this is
3497    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
3498    linking step for the pcreposix library.
3499    
3500    5. PCRE was failing to diagnose the case of two named groups with the same
3501    name.
3502    
3503    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
3504    literal character that is needed in the subject for a match, and scans along to
3505    ensure that it is present before embarking on the full matching process. This
3506    saves time in cases of nested unlimited repeats that are never going to match.
3507    Problem: the scan can take a lot of time if the subject is very long (e.g.
3508    megabytes), thus penalizing straightforward matches. It is now done only if the
3509    amount of subject to be scanned is less than 1000 bytes.
3510    
3511    7. A lesser problem with the same optimization is that it was recording the
3512    first character of an anchored pattern as "needed", thus provoking a search
3513    right along the subject, even when the first match of the pattern was going to
3514    fail. The "needed" character is now not set for anchored patterns, unless it
3515    follows something in the pattern that is of non-fixed length. Thus, it still
3516    fulfils its original purpose of finding quick non-matches in cases of nested
3517    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
3518    
3519    
3520    Version 4.0 17-Feb-03
3521    ---------------------
3522    
3523    1. If a comment in an extended regex that started immediately after a meta-item
3524    extended to the end of string, PCRE compiled incorrect data. This could lead to
3525    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
3526    
3527    2. Moved to autoconf 2.53 and libtool 1.4.2.
3528    
3529    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
3530    the special perltest8 script is no longer needed - all the tests can be run
3531    from a single perltest script.
3532    
3533    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
3534    by \s. It has now been removed in PCRE. This means it isn't recognized as
3535    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
3536    class [:space:] *does* include VT, thereby creating a mess.
3537    
3538    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
3539    space and tab.
3540    
3541    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
3542    its new features into the main test script, reducing the number of scripts.
3543    
3544    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
3545    were backward compatible, and made the (?i) apply to the whole pattern, as if
3546    /i were given. Now it behaves more logically, and applies the option setting
3547    only to what follows. PCRE has been changed to follow suit. However, if it
3548    finds options settings right at the start of the pattern, it extracts them into
3549    the global options, as before. Thus, they show up in the info data.
3550    
3551    8. Added support for the \Q...\E escape sequence. Characters in between are
3552    treated as literals. This is slightly different from Perl in that $ and @ are
3553    also handled as literals inside the quotes. In Perl, they will cause variable
3554    interpolation. Note the following examples:
3555    
3556        Pattern            PCRE matches      Perl matches
3557    
3558        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
3559        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
3560        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
3561    
3562    For compatibility with Perl, \Q...\E sequences are recognized inside character
3563    classes as well as outside them.
3564    
3565    9. Re-organized 3 code statements in pcretest to avoid "overflow in
3566    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
3567    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
3568    signed/unsigned warnings.
3569    
3570    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
3571    option for pcretest, so I've replaced it by a simple function that does just
3572    that job.
3573    
3574    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
3575    "pcregrep -".
3576    
3577    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
3578    Java package. This provides some syntactic sugar for simple cases of what my
3579    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
3580    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
3581    item, you can use this simplified notation. Note that only makes sense with
3582    greedy quantifiers. Consequently, the use of the possessive quantifier forces
3583    greediness, whatever the setting of the PCRE_UNGREEDY option.
3584    
3585    13. A change of greediness default within a pattern was not taking effect at
3586    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
3587    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
3588    was abstracted outside.
3589    
3590    14. PCRE now supports the \G assertion. It is true when the current matching
3591    position is at the start point of the match. This differs from \A when the
3592    starting offset is non-zero. Used with the /g option of pcretest (or similar
3593    code), it works in the same way as it does for Perl's /g option. If all
3594    alternatives of a regex begin with \G, the expression is anchored to the start
3595    match position, and the "anchored" flag is set in the compiled expression.
3596    
3597    15. Some bugs concerning the handling of certain option changes within patterns
3598    have been fixed. These applied to options other than (?ims). For example,
3599    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have