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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  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 recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
39    
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
42    
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
44    
45    9.  (*MARK) control verb is now supported by the JIT compiler.
46    
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
49    
50    11. Add PCRE_INFO_MAXLOOKBEHIND.
51    
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
57    
58    13. (*COMMIT) is now correctly confined to within a recursive subpattern call.
59    
60    14. It is now possible to link pcretest with libedit as an alternative to
61        libreadline.
62    
63    
64    Version 8.30 04-February-2012
65    -----------------------------
66    
67    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
68        name is defined in ctype.h.
69    
70    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
71        only in quite long subpatterns.
72    
73    3.  Removed the function pcre_info(), which has been obsolete and deprecated
74        since it was replaced by pcre_fullinfo() in February 2000.
75    
76    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
77        match a (*MARK), and the match failed at the start of the subject, a
78        reference to memory before the start of the subject could occur. This bug
79        was introduced by fix 17 of release 8.21.
80    
81    5.  A reference to an unset group with zero minimum repetition was giving
82        totally wrong answers (in non-JavaScript-compatibility mode). For example,
83        /(another)?(\1?)test/ matched against "hello world test". This bug was
84        introduced in release 8.13.
85    
86    6.  Add support for 16-bit character strings (a large amount of work involving
87        many changes and refactorings).
88    
89    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
90        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
91        from a file.
92    
93    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
94        rounding is not applied in this particular case).
95    
96    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
97        if they appear, or are escaped, in patterns.
98    
99    10. Get rid of a number of -Wunused-but-set-variable warnings.
100    
101    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
102        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
103        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
104        also returns the mark "x". This bug applied to capturing parentheses,
105        non-capturing parentheses, and atomic parentheses. It also applied to some
106        assertions.
107    
108    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
109        information out of configure.ac instead of relying on pcre.h.generic, which
110        is not stored in the repository.
111    
112    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
113        -lreadline.
114    
115    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
116    
117    15. Applied Graycode's patch to put the top-level frame on the stack rather
118        than the heap when not using the stack for recursion. This gives a
119        performance improvement in many cases when recursion is not deep.
120    
121    16. Experimental code added to "pcretest -C" to output the stack frame size.
122    
123    
124    Version 8.21 12-Dec-2011
125    ------------------------
126    
127    1.  Updating the JIT compiler.
128    
129    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
130        are added as well.
131    
132    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
133        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
134        calling _pcre_jit_exec. Some extra comments are added.
135    
136    4.  (*MARK) settings inside atomic groups that do not contain any capturing
137        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
138        was introduced by change 18 for 8.20.
139    
140    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
141        ECMA-262 standard.
142    
143    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
144        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
145        This bug was probably introduced by change 9 of 8.13.
146    
147    7.  While fixing 6 above, I noticed that a number of other items were being
148        incorrectly rejected as "not fixed length". This arose partly because newer
149        opcodes had not been added to the fixed-length checking code. I have (a)
150        corrected the bug and added tests for these items, and (b) arranged for an
151        error to occur if an unknown opcode is encountered while checking for fixed
152        length instead of just assuming "not fixed length". The items that were
153        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
154        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
155        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
156    
157    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
158        being incorrectly compiled and would have given unpredicatble results.
159    
160    9.  A possessively repeated subpattern with minimum repeat count greater than
161        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
162        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
163        the first (A) could occur when it should not.
164    
165    10. Add a cast and remove a redundant test from the code.
166    
167    11. JIT should use pcre_malloc/pcre_free for allocation.
168    
169    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
170        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
171        is anything other than /usr, -L is still shown).
172    
173    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
174    
175    14. Perl does not support \N without a following name in a [] class; PCRE now
176        also gives an error.
177    
178    15. If a forward reference was repeated with an upper limit of around 2000,
179        it caused the error "internal error: overran compiling workspace". The
180        maximum number of forward references (including repeats) was limited by the
181        internal workspace, and dependent on the LINK_SIZE. The code has been
182        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
183        the default depends on LINK_SIZE. There is a new upper limit (for safety)
184        of around 200,000 forward references. While doing this, I also speeded up
185        the filling in of repeated forward references.
186    
187    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
188        incorrectly expecting the subject to contain another "a" after the start.
189    
190    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
191        in the match, the SKIP should be ignored. This was not happening; instead
192        the SKIP was being treated as NOMATCH. For patterns such as
193        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
194        tested.
195    
196    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
197        now much more compatible with Perl, in particular in cases where the result
198        is a non-match for a non-anchored pattern. For example, if
199        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
200        "m", where previously it did not return a name. A side effect of this
201        change is that for partial matches, the last encountered mark name is
202        returned, as for non matches. A number of tests that were previously not
203        Perl-compatible have been moved into the Perl-compatible test files. The
204        refactoring has had the pleasing side effect of removing one argument from
205        the match() function, thus reducing its stack requirements.
206    
207    19. If the /S+ option was used in pcretest to study a pattern using JIT,
208        subsequent uses of /S (without +) incorrectly behaved like /S+.
209    
210    21. Retrieve executable code size support for the JIT compiler and fixing
211        some warnings.
212    
213    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
214        not work when the shorter character appeared right at the end of the
215        subject string.
216    
217    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
218        systems.
219    
220    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
221        output it when the /M option is used in pcretest.
222    
223    25. The CheckMan script was not being included in the distribution. Also, added
224        an explicit "perl" to run Perl scripts from the PrepareRelease script
225        because this is reportedly needed in Windows.
226    
227    26. If study data was being save in a file and studying had not found a set of
228        "starts with" bytes for the pattern, the data written to the file (though
229        never used) was taken from uninitialized memory and so caused valgrind to
230        complain.
231    
232    27. Updated RunTest.bat as provided by Sheri Pierce.
233    
234    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
235    
236    29. Computation of memory usage for the table of capturing group names was
237        giving an unnecessarily large value.
238    
239    
240    Version 8.20 21-Oct-2011
241    ------------------------
242    
243    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
244        a POSIX class. After further experiments with Perl, which convinced me that
245        Perl has bugs and confusions, a closing square bracket is no longer allowed
246        in a POSIX name. This bug also affected patterns with classes that started
247        with full stops.
248    
249    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
250        captured substring, but while checking the failing first alternative,
251        substring 1 is temporarily captured. If the output vector supplied to
252        pcre_exec() was not big enough for this capture, the yield of the function
253        was still zero ("insufficient space for captured substrings"). This cannot
254        be totally fixed without adding another stack variable, which seems a lot
255        of expense for a edge case. However, I have improved the situation in cases
256        such as /(a)(b)x|abc/ matched against "abc", where the return code
257        indicates that fewer than the maximum number of slots in the ovector have
258        been set.
259    
260    3.  Related to (2) above: when there are more back references in a pattern than
261        slots in the output vector, pcre_exec() uses temporary memory during
262        matching, and copies in the captures as far as possible afterwards. It was
263        using the entire output vector, but this conflicts with the specification
264        that only 2/3 is used for passing back captured substrings. Now it uses
265        only the first 2/3, for compatibility. This is, of course, another edge
266        case.
267    
268    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
269        main code base, and can be used by building with --enable-jit. When this is
270        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
271        runtime --no-jit option is given.
272    
273    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
274        ovector, the return from the function was zero, implying that there were
275        other matches that did not fit. The correct "exactly full" value is now
276        returned.
277    
278    6.  If a subpattern that was called recursively or as a subroutine contained
279        (*PRUNE) or any other control that caused it to give a non-standard return,
280        invalid errors such as "Error -26 (nested recursion at the same subject
281        position)" or even infinite loops could occur.
282    
283    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
284        computing the minimum length on reaching *ACCEPT, and so ended up with the
285        wrong value of 1 rather than 0. Further investigation indicates that
286        computing a minimum subject length in the presence of *ACCEPT is difficult
287        (think back references, subroutine calls), and so I have changed the code
288        so that no minimum is registered for a pattern that contains *ACCEPT.
289    
290    8.  If (*THEN) was present in the first (true) branch of a conditional group,
291        it was not handled as intended. [But see 16 below.]
292    
293    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
294        Sheri Pierce.
295    
296    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
297        the first byte in a match must be "a".
298    
299    11. Change 17 for 8.13 increased the recursion depth for patterns like
300        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
301        pattern contains any instances of (*THEN). If it does not, the old
302        optimizations are restored. It would be nice to do this on a per-group
303        basis, but at the moment that is not feasible.
304    
305    12. In some environments, the output of pcretest -C is CRLF terminated. This
306        broke RunTest's code that checks for the link size. A single white space
307        character after the value is now allowed for.
308    
309    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
310        For "fr", it uses the Windows-specific input and output files.
311    
312    14. If (*THEN) appeared in a group that was called recursively or as a
313        subroutine, it did not work as intended. [But see next item.]
314    
315    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
316        pattern fragments (but not containing any | characters). If A and B are
317        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
318        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
319        D. In other words, Perl considers parentheses that do not contain any |
320        characters to be part of a surrounding alternative, whereas PCRE was
321        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
322        differently. PCRE now behaves in the same way as Perl, except in the case
323        of subroutine/recursion calls such as (?1) which have in any case always
324        been different (but PCRE had them first :-).
325    
326    16. Related to 15 above: Perl does not treat the | in a conditional group as
327        creating alternatives. Such a group is treated in the same way as an
328        ordinary group without any | characters when processing (*THEN). PCRE has
329        been changed to match Perl's behaviour.
330    
331    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
332        RunGrepTest script failed.
333    
334    18. Change 22 for version 13 caused atomic groups to use more stack. This is
335        inevitable for groups that contain captures, but it can lead to a lot of
336        stack use in large patterns. The old behaviour has been restored for atomic
337        groups that do not contain any capturing parentheses.
338    
339    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
340        suppress the check for a minimum subject length at run time. (If it was
341        given to pcre_exec() or pcre_dfa_exec() it did work.)
342    
343    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
344        fail to work when decoding hex characters in data strings in EBCDIC
345        environments.
346    
347    21. It appears that in at least one Mac OS environment, the isxdigit() function
348        is implemented as a macro that evaluates to its argument more than once,
349        contravening the C 90 Standard (I haven't checked a later standard). There
350        was an instance in pcretest which caused it to go wrong when processing
351        \x{...} escapes in subject strings. The has been rewritten to avoid using
352        things like p++ in the argument of isxdigit().
353    
354    
355    Version 8.13 16-Aug-2011
356    ------------------------
357    
358    1.  The Unicode data tables have been updated to Unicode 6.0.0.
359    
360    2.  Two minor typos in pcre_internal.h have been fixed.
361    
362    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
363        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
364        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
365    
366    4.  There were a number of related bugs in the code for matching backrefences
367        caselessly in UTF-8 mode when codes for the characters concerned were
368        different numbers of bytes. For example, U+023A and U+2C65 are an upper
369        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
370        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
371        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
372        2-byte code at the end of the subject (it thought there wasn't enough data
373        left).
374    
375    5.  Comprehensive information about what went wrong is now returned by
376        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
377        as the output vector has at least 2 elements. The offset of the start of
378        the failing character and a reason code are placed in the vector.
379    
380    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
381        now returned is for the first byte of the failing character, instead of the
382        last byte inspected. This is an incompatible change, but I hope it is small
383        enough not to be a problem. It makes the returned offset consistent with
384        pcre_exec() and pcre_dfa_exec().
385    
386    7.  pcretest now gives a text phrase as well as the error number when
387        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
388        failure, the offset and reason code are output.
389    
390    8.  When \R was used with a maximizing quantifier it failed to skip backwards
391        over a \r\n pair if the subsequent match failed. Instead, it just skipped
392        back over a single character (\n). This seems wrong (because it treated the
393        two characters as a single entity when going forwards), conflicts with the
394        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
395        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
396        has been changed.
397    
398    9.  Some internal refactoring has changed the processing so that the handling
399        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
400        time (the PCRE_DOTALL option was changed this way some time ago: version
401        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
402        which was always a bit of a fudge. It also means that there is one less
403        argument for the match() function, which reduces its stack requirements
404        slightly. This change also fixes an incompatibility with Perl: the pattern
405        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
406    
407    10. More internal refactoring has drastically reduced the number of recursive
408        calls to match() for possessively repeated groups such as (abc)++ when
409        using pcre_exec().
410    
411    11. While implementing 10, a number of bugs in the handling of groups were
412        discovered and fixed:
413    
414        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
415        (a|)*(?1) gave a compile-time internal error.
416        ((a|)+)+  did not notice that the outer group could match an empty string.
417        (^a|^)+   was not marked as anchored.
418        (.*a|.*)+ was not marked as matching at start or after a newline.
419    
420    12. Yet more internal refactoring has removed another argument from the match()
421        function. Special calls to this function are now indicated by setting a
422        value in a variable in the "match data" data block.
423    
424    13. Be more explicit in pcre_study() instead of relying on "default" for
425        opcodes that mean there is no starting character; this means that when new
426        ones are added and accidentally left out of pcre_study(), testing should
427        pick them up.
428    
429    14. The -s option of pcretest has been documented for ages as being an old
430        synonym of -m (show memory usage). I have changed it to mean "force study
431        for every regex", that is, assume /S for every regex. This is similar to -i
432        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
433        using it. It makes it easier to run collections of tests with and without
434        study enabled, and thereby test pcre_study() more easily. All the standard
435        tests are now run with and without -s (but some patterns can be marked as
436        "never study" - see 20 below).
437    
438    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
439        restoration of the capturing data to the outer values was not happening
440        correctly.
441    
442    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
443        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
444        pattern had matched an empty string, and so incorrectly returned a no
445        match.
446    
447    17. There was optimizing code for the last branch of non-capturing parentheses,
448        and also for the obeyed branch of a conditional subexpression, which used
449        tail recursion to cut down on stack usage. Unfortunately, now that there is
450        the possibility of (*THEN) occurring in these branches, tail recursion is
451        no longer possible because the return has to be checked for (*THEN). These
452        two optimizations have therefore been removed. [But see 8.20/11 above.]
453    
454    18. If a pattern containing \R was studied, it was assumed that \R always
455        matched two bytes, thus causing the minimum subject length to be
456        incorrectly computed because \R can also match just one byte.
457    
458    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
459        was incorrectly computed.
460    
461    20. If /S is present twice on a test pattern in pcretest input, it now
462        *disables* studying, thereby overriding the use of -s on the command line
463        (see 14 above). This is necessary for one or two tests to keep the output
464        identical in both cases.
465    
466    21. When (*ACCEPT) was used in an assertion that matched an empty string and
467        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
468    
469    22. When an atomic group that contained a capturing parenthesis was
470        successfully matched, but the branch in which it appeared failed, the
471        capturing was not being forgotten if a higher numbered group was later
472        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
473        group 1 to "a", when in fact it should be unset. This applied to multi-
474        branched capturing and non-capturing groups, repeated or not, and also to
475        positive assertions (capturing in negative assertions does not happen
476        in PCRE) and also to nested atomic groups.
477    
478    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
479        subject after a captured substring, to make it easier to tell which of a
480        number of identical substrings has been captured.
481    
482    24. The way atomic groups are processed by pcre_exec() has been changed so that
483        if they are repeated, backtracking one repetition now resets captured
484        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
485        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
486        "aaa". Previously, it would have been "a". As part of this code
487        refactoring, the way recursive calls are handled has also been changed.
488    
489    25. If an assertion condition captured any substrings, they were not passed
490        back unless some other capturing happened later. For example, if
491        (?(?=(a))a) was matched against "a", no capturing was returned.
492    
493    26. When studying a pattern that contained subroutine calls or assertions,
494        the code for finding the minimum length of a possible match was handling
495        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
496        group 1 called group 2 while simultaneously a separate group 2 called group
497        1). A stack overflow occurred in this case. I have fixed this by limiting
498        the recursion depth to 10.
499    
500    27. Updated RunTest.bat in the distribution to the version supplied by Tom
501        Fortmann. This supports explicit test numbers on the command line, and has
502        argument validation and error reporting.
503    
504    28. An instance of \X with an unlimited repeat could fail if at any point the
505        first character it looked at was a mark character.
506    
507    29. Some minor code refactoring concerning Unicode properties and scripts
508        should reduce the stack requirement of match() slightly.
509    
510    30. Added the '=' option to pcretest to check the setting of unused capturing
511        slots at the end of the pattern, which are documented as being -1, but are
512        not included in the return count.
513    
514    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
515        compiled something random. Now it gives a compile-time error (as does
516        Perl).
517    
518    32. A *MARK encountered during the processing of a positive assertion is now
519        recorded and passed back (compatible with Perl).
520    
521    33. If --only-matching or --colour was set on a pcregrep call whose pattern
522        had alternative anchored branches, the search for a second match in a line
523        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
524        matched the line "0102" twice. The same bug affected patterns that started
525        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
526        twice.
527    
528    34. Previously, PCRE did not allow quantification of assertions. However, Perl
529        does, and because of capturing effects, quantifying parenthesized
530        assertions may at times be useful. Quantifiers are now allowed for
531        parenthesized assertions.
532    
533    35. A minor code tidy in pcre_compile() when checking options for \R usage.
534    
535    36. \g was being checked for fancy things in a character class, when it should
536        just be a literal "g".
537    
538    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
539        appearance of a nested POSIX class supersedes an apparent external class.
540        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
541        unescaped square brackets may also appear as part of class names. For
542        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
543        more like Perl. (But see 8.20/1 above.)
544    
545    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
546        was because it thought it was \N{name}, which is not supported).
547    
548    39. Add minix to OS list not supporting the -S option in pcretest.
549    
550    40. PCRE tries to detect cases of infinite recursion at compile time, but it
551        cannot analyze patterns in sufficient detail to catch mutual recursions
552        such as ((?1))((?2)). There is now a runtime test that gives an error if a
553        subgroup is called recursively as a subpattern for a second time at the
554        same position in the subject string. In previous releases this might have
555        been caught by the recursion limit, or it might have run out of stack.
556    
557    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
558        happen only once. PCRE was, however incorrectly giving a compile time error
559        "recursive call could loop indefinitely" because it cannot analyze the
560        pattern in sufficient detail. The compile time test no longer happens when
561        PCRE is compiling a conditional subpattern, but actual runaway loops are
562        now caught at runtime (see 40 above).
563    
564    42. It seems that Perl allows any characters other than a closing parenthesis
565        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
566        has been changed to be the same.
567    
568    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
569        as not to get warnings when autogen.sh is called. Also changed
570        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
571    
572    44. To help people who use pcregrep to scan files containing exceedingly long
573        lines, the following changes have been made:
574    
575        (a) The default value of the buffer size parameter has been increased from
576            8K to 20K. (The actual buffer used is three times this size.)
577    
578        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
579            PCRE is built.
580    
581        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
582            to be set at run time.
583    
584        (d) Numerical values in pcregrep options can be followed by K or M, for
585            example --buffer-size=50K.
586    
587        (e) If a line being scanned overflows pcregrep's buffer, an error is now
588            given and the return code is set to 2.
589    
590    45. Add a pointer to the latest mark to the callout data block.
591    
592    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
593        partial match of an empty string instead of no match. This was specific to
594        the use of ".".
595    
596    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
597        complete match instead of a partial match. This bug was dependent on both
598        the PCRE_UTF8 and PCRE_DOTALL options being set.
599    
600    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
601        starting byte set, because \b was not being ignored.
602    
603    
604    Version 8.12 15-Jan-2011
605    ------------------------
606    
607    1.  Fixed some typos in the markup of the man pages, and wrote a script that
608        checks for such things as part of the documentation building process.
609    
610    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
611        --match-limit and --recursion-limit options (added for 8.11). In
612        particular, this made one of the standard tests fail. (The integer value
613        went into the wrong half of a long int.)
614    
615    3.  If the --colour option was given to pcregrep with -v (invert match), it
616        did strange things, either producing crazy output, or crashing. It should,
617        of course, ignore a request for colour when reporting lines that do not
618        match.
619    
620    4.  Another pcregrep bug caused similar problems if --colour was specified with
621        -M (multiline) and the pattern match finished with a line ending.
622    
623    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
624        matched in multiline mode, the following line was shown as part of the
625        match. This seems wrong, so I have changed it.
626    
627    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
628        the check for further matches in the same line (so they could be coloured)
629        to overrun the end of the current line. If another match was found, it was
630        incorrectly shown (and then shown again when found in the next line).
631    
632    7.  If pcregrep was compiled under Windows, there was a reference to the
633        function pcregrep_exit() before it was defined. I am assuming this was
634        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
635        reported by a user. I've moved the definition above the reference.
636    
637    
638    Version 8.11 10-Dec-2010
639    ------------------------
640    
641    1.  (*THEN) was not working properly if there were untried alternatives prior
642        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
643        backtracked to try for "b" instead of moving to the next alternative branch
644        at the same level (in this case, to look for "c"). The Perl documentation
645        is clear that when (*THEN) is backtracked onto, it goes to the "next
646        alternative in the innermost enclosing group".
647    
648    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
649        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
650        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
651        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
652        (*THEN).
653    
654    3.  If \s appeared in a character class, it removed the VT character from
655        the class, even if it had been included by some previous item, for example
656        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
657        of \s, but is part of the POSIX "space" class.)
658    
659    4.  A partial match never returns an empty string (because you can always
660        match an empty string at the end of the subject); however the checking for
661        an empty string was starting at the "start of match" point. This has been
662        changed to the "earliest inspected character" point, because the returned
663        data for a partial match starts at this character. This means that, for
664        example, /(?<=abc)def/ gives a partial match for the subject "abc"
665        (previously it gave "no match").
666    
667    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
668        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
669        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
670        has an implication that the given string is incomplete (because a partial
671        match is preferred over a full match). For this reason, these items now
672        give a partial match in this situation. [Aside: previously, the one case
673        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
674        match rather than a full match, which was wrong by the old rules, but is
675        now correct.]
676    
677    6.  There was a bug in the handling of #-introduced comments, recognized when
678        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
679        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
680        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
681        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
682        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
683        places in pcre_compile().
684    
685    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
686        comments when looking ahead for named forward references to subpatterns,
687        the only newline sequence it recognized was NL. It now handles newlines
688        according to the set newline convention.
689    
690    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
691        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
692        cater for a lack of strerror(). These oversights have been fixed.
693    
694    9.  Added --match-limit and --recursion-limit to pcregrep.
695    
696    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
697    
698    11. When the -o option was used, pcregrep was setting a return code of 1, even
699        when matches were found, and --line-buffered was not being honoured.
700    
701    12. Added an optional parentheses number to the -o and --only-matching options
702        of pcregrep.
703    
704    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
705        can match an empty string. The code to do it in pcretest and pcredemo
706        needed fixing:
707    
708        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
709            only one byte after an empty string match just before CRLF (this case
710            just got forgotten; "any" and "anycrlf" were OK).
711    
712        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
713            mode when an empty string match preceded an ASCII character followed by
714            a non-ASCII character. (The code for advancing by one character rather
715            than one byte was nonsense.)
716    
717        (c) The pcredemo.c sample program did not have any code at all to handle
718            the cases when CRLF is a valid newline sequence.
719    
720    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
721        as a starting offset was within the subject string. There is now a new
722        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
723        negative or greater than the length of the string. In order to test this,
724        pcretest is extended to allow the setting of negative starting offsets.
725    
726    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
727        starting offset points to the beginning of a UTF-8 character was
728        unnecessarily clumsy. I tidied it up.
729    
730    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
731        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
732    
733    17. Nobody had reported that the --include_dir option, which was added in
734        release 7.7 should have been called --include-dir (hyphen, not underscore)
735        for compatibility with GNU grep. I have changed it to --include-dir, but
736        left --include_dir as an undocumented synonym, and the same for
737        --exclude-dir, though that is not available in GNU grep, at least as of
738        release 2.5.4.
739    
740    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
741        characters from a string of bytes) have been redefined so as not to use
742        loops, in order to improve performance in some environments. At the same
743        time, I abstracted some of the common code into auxiliary macros to save
744        repetition (this should not affect the compiled code).
745    
746    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
747        compile-time error is now given if \c is not followed by an ASCII
748        character, that is, a byte less than 128. (In EBCDIC mode, the code is
749        different, and any byte value is allowed.)
750    
751    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
752        START_OPTIMIZE option, which is now allowed at compile time - but just
753        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
754        to pcregrep and other applications that have no direct access to PCRE
755        options. The new /Y option in pcretest sets this option when calling
756        pcre_compile().
757    
758    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
759        back references. Groups containing recursive back references were forced to
760        be atomic by that change, but in the case of named groups, the amount of
761        memory required was incorrectly computed, leading to "Failed: internal
762        error: code overflow". This has been fixed.
763    
764    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
765        pcretest.c, to avoid build problems in some Borland environments.
766    
767    
768    Version 8.10 25-Jun-2010
769    ------------------------
770    
771    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
772        THEN.
773    
774    2.  (*ACCEPT) was not working when inside an atomic group.
775    
776    3.  Inside a character class, \B is treated as a literal by default, but
777        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
778        causes the error). The code is unchanged, but I tidied the documentation.
779    
780    4.  Inside a character class, PCRE always treated \R and \X as literals,
781        whereas Perl faults them if its -w option is set. I have changed PCRE so
782        that it faults them when PCRE_EXTRA is set.
783    
784    5.  Added support for \N, which always matches any character other than
785        newline. (It is the same as "." when PCRE_DOTALL is not set.)
786    
787    6.  When compiling pcregrep with newer versions of gcc which may have
788        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
789        declared with attribute warn_unused_result" were given. Just casting the
790        result to (void) does not stop the warnings; a more elaborate fudge is
791        needed. I've used a macro to implement this.
792    
793    7.  Minor change to pcretest.c to avoid a compiler warning.
794    
795    8.  Added four artifical Unicode properties to help with an option to make
796        \s etc use properties (see next item). The new properties are: Xan
797        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
798    
799    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
800        use Unicode properties. (*UCP) at the start of a pattern can be used to set
801        this option. Modified pcretest to add /W to test this facility. Added
802        REG_UCP to make it available via the POSIX interface.
803    
804    10. Added --line-buffered to pcregrep.
805    
806    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
807        studied, and the match started with a letter with a code point greater than
808        127 whose first byte was different to the first byte of the other case of
809        the letter, the other case of this starting letter was not recognized
810        (#976).
811    
812    12. If a pattern that was studied started with a repeated Unicode property
813        test, for example, \p{Nd}+, there was the theoretical possibility of
814        setting up an incorrect bitmap of starting bytes, but fortunately it could
815        not have actually happened in practice until change 8 above was made (it
816        added property types that matched character-matching opcodes).
817    
818    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
819        possible starting bytes for non-anchored patterns.
820    
821    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
822        \R, and also a number of cases that involve Unicode properties, both
823        explicit and implicit when PCRE_UCP is set.
824    
825    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
826        input, it could crash or give wrong results if characters with values
827        greater than 0xc0 were present in the subject string. (Detail: it assumed
828        UTF-8 input when processing these items.)
829    
830    16. Added a lot of (int) casts to avoid compiler warnings in systems where
831        size_t is 64-bit (#991).
832    
833    17. Added a check for running out of memory when PCRE is compiled with
834        --disable-stack-for-recursion (#990).
835    
836    18. If the last data line in a file for pcretest does not have a newline on
837        the end, a newline was missing in the output.
838    
839    19. The default pcre_chartables.c file recognizes only ASCII characters (values
840        less than 128) in its various bitmaps. However, there is a facility for
841        generating tables according to the current locale when PCRE is compiled. It
842        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
843        characters, are recognized by isspace() and therefore were getting set in
844        these tables, and indeed these tables seem to approximate to ISO 8859. This
845        caused a problem in UTF-8 mode when pcre_study() was used to create a list
846        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
847        which of course cannot start UTF-8 characters. I have changed the code so
848        that only real ASCII characters (less than 128) and the correct starting
849        bytes for UTF-8 encodings are set for characters greater than 127 when in
850        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
851        altogether.)
852    
853    20. Added the /T option to pcretest so as to be able to run tests with non-
854        standard character tables, thus making it possible to include the tests
855        used for 19 above in the standard set of tests.
856    
857    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
858        reference to a subpattern the other side of a comment that contains an
859        opening parenthesis caused either an internal compiling error, or a
860        reference to the wrong subpattern.
861    
862    
863    Version 8.02 19-Mar-2010
864    ------------------------
865    
866    1.  The Unicode data tables have been updated to Unicode 5.2.0.
867    
868    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
869        configured.
870    
871    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
872        original author of that file, following a query about its status.
873    
874    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
875        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
876    
877    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
878        quantifier applied to a forward-referencing subroutine call, could compile
879        incorrect code or give the error "internal error: previously-checked
880        referenced subpattern not found".
881    
882    6.  Both MS Visual Studio and Symbian OS have problems with initializing
883        variables to point to external functions. For these systems, therefore,
884        pcre_malloc etc. are now initialized to local functions that call the
885        relevant global functions.
886    
887    7.  There were two entries missing in the vectors called coptable and poptable
888        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
889        I've fixed the data, and added a kludgy way of testing at compile time that
890        the lengths are correct (equal to the number of opcodes).
891    
892    8.  Following on from 7, I added a similar kludge to check the length of the
893        eint vector in pcreposix.c.
894    
895    9.  Error texts for pcre_compile() are held as one long string to avoid too
896        much relocation at load time. To find a text, the string is searched,
897        counting zeros. There was no check for running off the end of the string,
898        which could happen if a new error number was added without updating the
899        string.
900    
901    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
902    
903    11. \K was not working if it appeared in an atomic group or in a group that
904        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
905        \K is "not well defined" if used in an assertion. PCRE now accepts it if
906        the assertion is positive, but not if it is negative.
907    
908    12. Change 11 fortuitously reduced the size of the stack frame used in the
909        "match()" function of pcre_exec.c by one pointer. Forthcoming
910        implementation of support for (*MARK) will need an extra pointer on the
911        stack; I have reserved it now, so that the stack frame size does not
912        decrease.
913    
914    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
915        item in branch that calls a recursion is a subroutine call - as in the
916        second branch in the above example - was incorrectly given the compile-
917        time error "recursive call could loop indefinitely" because pcre_compile()
918        was not correctly checking the subroutine for matching a non-empty string.
919    
920    14. The checks for overrunning compiling workspace could trigger after an
921        overrun had occurred. This is a "should never occur" error, but it can be
922        triggered by pathological patterns such as hundreds of nested parentheses.
923        The checks now trigger 100 bytes before the end of the workspace.
924    
925    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
926    
927    
928    Version 8.01 19-Jan-2010
929    ------------------------
930    
931    1.  If a pattern contained a conditional subpattern with only one branch (in
932        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
933        computed the wrong minimum data length (which is of course zero for such
934        subpatterns). This could cause incorrect "no match" results.
935    
936    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
937        the pattern is reset in the first branch, pcre_compile() failed with
938        "internal error: code overflow at offset...". This happened only when
939        the reset was to the original external option setting. (An optimization
940        abstracts leading options settings into an external setting, which was the
941        cause of this.)
942    
943    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
944        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
945        assertion pattern did not match (meaning that the assertion was true), it
946        was incorrectly treated as false if the SKIP had been reached during the
947        matching. This also applied to assertions used as conditions.
948    
949    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
950        assertion subpattern, including such a pattern used as a condition,
951        unpredictable results occurred, instead of the error return
952        PCRE_ERROR_DFA_UITEM.
953    
954    5.  The C++ GlobalReplace function was not working like Perl for the special
955        situation when an empty string is matched. It now does the fancy magic
956        stuff that is necessary.
957    
958    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
959        removed. (These were left over from very, very early versions of PCRE.)
960    
961    7.  Some cosmetic changes to the code to make life easier when compiling it
962        as part of something else:
963    
964        (a) Change DEBUG to PCRE_DEBUG.
965    
966        (b) In pcre_compile(), rename the member of the "branch_chain" structure
967            called "current" as "current_branch", to prevent a collision with the
968            Linux macro when compiled as a kernel module.
969    
970        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
971            prevent a collision with the Linux macro when compiled as a kernel
972            module.
973    
974    8.  In pcre_compile() there are some checks for integer overflows that used to
975        cast potentially large values to (double). This has been changed to that
976        when building, a check for int64_t is made, and if it is found, it is used
977        instead, thus avoiding the use of floating point arithmetic. (There is no
978        other use of FP in PCRE.) If int64_t is not found, the fallback is to
979        double.
980    
981    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
982        2005 (difference between two addresses compared to an unsigned value).
983    
984    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
985        custom one, because of the following reported problem in Windows:
986    
987          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
988              under Win32.
989          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
990              therefore missing the function definition.
991          - The compiler thus generates a "C" signature for the test function.
992          - The linker fails to find the "C" function.
993          - PCRE fails to configure if asked to do so against libbz2.
994    
995    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
996        messages were output:
997    
998          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
999          rerunning libtoolize, to keep the correct libtool macros in-tree.
1000          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1001    
1002        I have done both of these things.
1003    
1004    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1005        most of the time, it *can* run out if it is given a pattern that contains a
1006        runaway infinite recursion. I updated the discussion in the pcrestack man
1007        page.
1008    
1009    13. Now that we have gone to the x.xx style of version numbers, the minor
1010        version may start with zero. Using 08 or 09 is a bad idea because users
1011        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1012        interpreted as invalid octal numbers. I've updated the previous comment in
1013        configure.ac, and also added a check that gives an error if 08 or 09 are
1014        used.
1015    
1016    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1017        causing partial matching to fail when the end of the subject matched \W
1018        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1019    
1020    15. There were some discrepancies between the declarations in pcre_internal.h
1021        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1022        their definitions. The declarations used "const uschar *" and the
1023        definitions used USPTR. Even though USPTR is normally defined as "const
1024        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1025        reported that: "This difference in casting confuses some C++ compilers, for
1026        example, SunCC recognizes above declarations as different functions and
1027        generates broken code for hbpcre." I have changed the declarations to use
1028        USPTR.
1029    
1030    16. GNU libtool is named differently on some systems. The autogen.sh script now
1031        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1032        (FreeBSD).
1033    
1034    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1035        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1036        comment: "Figure out how to create a longlong from a string: strtoll and
1037        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1038        instance, but it only takes 2 args instead of 3!"
1039    
1040    18. A subtle bug concerned with back references has been fixed by a change of
1041        specification, with a corresponding code fix. A pattern such as
1042        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1043        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1044        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1045        same bug. Such groups have to be quantified to be useful, or contained
1046        inside another quantified group. (If there's no repetition, the reference
1047        can never match.) The problem arises because, having left the group and
1048        moved on to the rest of the pattern, a later failure that backtracks into
1049        the group uses the captured value from the final iteration of the group
1050        rather than the correct earlier one. I have fixed this in PCRE by forcing
1051        any group that contains a reference to itself to be an atomic group; that
1052        is, there cannot be any backtracking into it once it has completed. This is
1053        similar to recursive and subroutine calls.
1054    
1055    
1056    Version 8.00 19-Oct-09
1057  ----------------------  ----------------------
1058    
1059  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
1060      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
1061      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
1062      error.      error.
1063    
1064  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1065      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1066      in a Windows environment.      in a Windows environment.
1067    
1068  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
1069      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
1070      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
1071      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
1072      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
1073      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
1074      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
1075    
1076  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
1077      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
1078      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
1079      the old behaviour.      the old behaviour.
1080    
1081  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
1082      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
1083      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
1084      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
1085    
1086  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
1087      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1088    
1089  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1090      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
1091      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
1092      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
1093      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
1094      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
1095    
1096  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1097      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
1098      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1099      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1100      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
1101      result.      result.
1102    
1103  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
1104      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
1105      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
1106      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
1107      for the match and the offset of the end of the subject are set in them when      for the match and the offset of the end of the subject are set in them when
1108      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
1109    
1110  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1111      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
1112      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1113      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
1114      pcre_exec().  
1115    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1116  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
1117      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
1118      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1119      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
1120      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
1121      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
1122      final character ended with (*FAIL).  
   
1123  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1124      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
1125      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
1126      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
1127      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
1128      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
1129    
1130  13. The string returned by pcre_dfa_exec() after a partial match has been  13. The string returned by pcre_dfa_exec() after a partial match has been
1131      changed so that it starts at the first inspected character rather than the      changed so that it starts at the first inspected character rather than the
1132      first character of the match. This makes a difference only if the pattern      first character of the match. This makes a difference only if the pattern
1133      starts with a lookbehind assertion or \b or \B (\K is not supported by      starts with a lookbehind assertion or \b or \B (\K is not supported by
1134      pcre_dfa_exec()). It's an incompatible change, but it makes the two      pcre_dfa_exec()). It's an incompatible change, but it makes the two
1135      matching functions compatible, and I think it's the right thing to do.      matching functions compatible, and I think it's the right thing to do.
1136    
1137  14. Added a pcredemo man page, created automatically from the pcredemo.c file,  14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1138      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
1139      PCRE has not been installed from source.      PCRE has not been installed from source.
1140    
1141  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1142      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1143      library.      library.
1144    
1145  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1146      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1147      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
1148      these options useful.      these options useful.
1149    
1150  17. If a caller to the POSIX matching function regexec() passes a non-zero  17. If a caller to the POSIX matching function regexec() passes a non-zero
1151      value for nmatch with a NULL value for pmatch, the value of      value for nmatch with a NULL value for pmatch, the value of
1152      nmatch is forced to zero.      nmatch is forced to zero.
1153    
1154  18. RunGrepTest did not have a test for the availability of the -u option of  18. RunGrepTest did not have a test for the availability of the -u option of
1155      the diff command, as RunTest does. It now checks in the same way as      the diff command, as RunTest does. It now checks in the same way as
1156      RunTest, and also checks for the -b option.      RunTest, and also checks for the -b option.
1157    
1158  19. If an odd number of negated classes containing just a single character  19. If an odd number of negated classes containing just a single character
1159      interposed, within parentheses, between a forward reference to a named      interposed, within parentheses, between a forward reference to a named
1160      subpattern and the definition of the subpattern, compilation crashed with      subpattern and the definition of the subpattern, compilation crashed with
1161      an internal error, complaining that it could not find the referenced      an internal error, complaining that it could not find the referenced
1162      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1163      [The bug was that it was starting one character too far in when skipping      [The bug was that it was starting one character too far in when skipping
1164      over the character class, thus treating the ] as data rather than      over the character class, thus treating the ] as data rather than
1165      terminating the class. This meant it could skip too much.]      terminating the class. This meant it could skip too much.]
1166    
1167    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1168        /g option in pcretest when the pattern contains \K, which makes it possible
1169        to have an empty string match not at the start, even when the pattern is
1170        anchored. Updated pcretest and pcredemo to use this option.
1171    
1172    21. If the maximum number of capturing subpatterns in a recursion was greater
1173        than the maximum at the outer level, the higher number was returned, but
1174        with unset values at the outer level. The correct (outer level) value is
1175        now given.
1176    
1177    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1178        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1179        make it do so. The string so far is captured, making this feature
1180        compatible with Perl.
1181    
1182    23. The tests have been re-organized, adding tests 11 and 12, to make it
1183        possible to check the Perl 5.10 features against Perl 5.10.
1184    
1185    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1186        pattern matches a fixed length string. PCRE did not allow this; now it
1187        does. Neither allows recursion.
1188    
1189    25. I finally figured out how to implement a request to provide the minimum
1190        length of subject string that was needed in order to match a given pattern.
1191        (It was back references and recursion that I had previously got hung up
1192        on.) This code has now been added to pcre_study(); it finds a lower bound
1193        to the length of subject needed. It is not necessarily the greatest lower
1194        bound, but using it to avoid searching strings that are too short does give
1195        some useful speed-ups. The value is available to calling programs via
1196        pcre_fullinfo().
1197    
1198    26. While implementing 25, I discovered to my embarrassment that pcretest had
1199        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1200        study optimizations had never been tested with that matching function.
1201        Oops. What is worse, even when it was passed study data, there was a bug in
1202        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1203        were also very few tests of studied patterns with pcre_dfa_exec().
1204    
1205    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1206        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1207        on the other side of the coin, they are no longer allowed to have different
1208        names, because these cannot be distinguished in PCRE, and this has caused
1209        confusion. (This is a difference from Perl.)
1210    
1211    28. When duplicate subpattern names are present (necessarily with different
1212        numbers, as required by 27 above), and a test is made by name in a
1213        conditional pattern, either for a subpattern having been matched, or for
1214        recursion in such a pattern, all the associated numbered subpatterns are
1215        tested, and the overall condition is true if the condition is true for any
1216        one of them. This is the way Perl works, and is also more like the way
1217        testing by number works.
1218    
1219    
1220  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1221  ---------------------  ---------------------

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