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

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