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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.10 16-Jun-2010  Version 8.32
5    ------------
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
10    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
11        Patch by Daniel Richard G.
13    3.  Single character iterator optimizations in the JIT compiler.
15    4.  Improved JIT compiler optimizations for character ranges.
17    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
18        Reported by Giuseppe D'Angelo.
20    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
21        of a line, was being set incorrectly in cases where .* appeared inside
22        atomic brackets at the start of a pattern, or where there was a subsequent
23        *PRUNE or *SKIP.
25    7.  Improved instruction cache flush for POWER/PowerPC.
26        Patch by Daniel Richard G.
28    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
29        grep:
31        (a) There is now no limit to the number of patterns to be matched.
33        (b) An error is given if a pattern is too long.
35        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
36            are now supported.
38        (d) --exclude-from and --include-from (multiple use) have been added.
40        (e) Exclusions and inclusions now apply to all files and directories, not
41            just to those obtained from scanning a directory recursively.
43        (f) Multiple uses of -f and --file-list are now supported.
45        (g) In a Windows environment, the default for -d has been changed from
46            "read" (the GNU grep default) to "skip", because otherwise the presence
47            of a directory in the file list provokes an error.
49        (h) The documentation has been revised and clarified in places.
51    9.  Improve the matching speed of capturing brackets.
54    Version 8.31 06-July-2012
55    -------------------------
57    1.  Fixing a wrong JIT test case and some compiler warnings.
59    2.  Removed a bashism from the RunTest script.
61    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
62        to unsigned type, result still unsigned" that was given by an MS compiler
63        on encountering the code "-sizeof(xxx)".
65    4.  Partial matching support is added to the JIT compiler.
67    5.  Fixed several bugs concerned with partial matching of items that consist
68        of more than one character:
70        (a) /^(..)\1/ did not partially match "aba" because checking references was
71            done on an "all or nothing" basis. This also applied to repeated
72            references.
74        (b) \R did not give a hard partial match if \r was found at the end of the
75            subject.
77        (c) \X did not give a hard partial match after matching one or more
78            characters at the end of the subject.
80        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
81            a partial match for the string "\r".
83        (e) When newline was set to CRLF, the metacharacter "." did not recognize
84            a partial match for a CR character at the end of the subject string.
86    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
87        running pcretest, the text "(JIT)" added to the output whenever JIT is
88        actually used to run the match.
90    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
91        or /S+[+] with a digit between 1 and 7.
93    8.  OP_NOT now supports any UTF character not just single-byte ones.
95    9.  (*MARK) control verb is now supported by the JIT compiler.
97    10. The command "./RunTest list" lists the available tests without actually
98        running any of them. (Because I keep forgetting what they all are.)
102    12. Applied a (slightly modified) user-supplied patch that improves performance
103        when the heap is used for recursion (compiled with --disable-stack-for-
104        recursion). Instead of malloc and free for each heap frame each time a
105        logical recursion happens, frames are retained on a chain and re-used where
106        possible. This sometimes gives as much as 30% improvement.
108    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
109        call.
111    14. As documented, (*COMMIT) is now confined to within a positive assertion.
113    15. It is now possible to link pcretest with libedit as an alternative to
114        libreadline.
116    16. (*COMMIT) control verb is now supported by the JIT compiler.
118    17. The Unicode data tables have been updated to Unicode 6.1.0.
120    18. Added --file-list option to pcregrep.
122    19. Added binary file support to pcregrep, including the -a, --binary-files,
123        -I, and --text options.
125    20. The madvise function is renamed for posix_madvise for QNX compatibility
126        reasons. Fixed by Giuseppe D'Angelo.
128    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
130    22. Changed the option for creating symbolic links for 16-bit man pages from
131        -s to -sf so that re-installing does not cause issues.
133    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
135    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
136        matches in certain environments (the workspace was not being correctly
137        retained). Also added to pcre_dfa_exec() a simple plausibility check on
138        some of the workspace data at the beginning of a restart.
140    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
141        was not doing so when it should - probably a typo introduced by SVN 528
142        (change 8.10/14).
144    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
145        \w+ when the character tables indicated that \x{c4} was a word character.
146        There were several related cases, all because the tests for doing a table
147        lookup were testing for characters less than 127 instead of 255.
149    27. If a pattern contains capturing parentheses that are not used in a match,
150        their slots in the ovector are set to -1. For those that are higher than
151        any matched groups, this happens at the end of processing. In the case when
152        there were back references that the ovector was too small to contain
153        (causing temporary malloc'd memory to be used during matching), and the
154        highest capturing number was not used, memory off the end of the ovector
155        was incorrectly being set to -1. (It was using the size of the temporary
156        memory instead of the true size.)
158    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
159        ovector size, it uses memory at the end of the block that it has got.
161    29. Check for an overlong MARK name and give an error at compile time. The
162        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
164    30. JIT compiler update.
166    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
167        Rill for the patch.
169    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
171    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
173    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
174        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
175        was enabled.
177    35. Improve JIT code generation for greedy plus quantifier.
179    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
180        1 to "aa" instead of to an empty string. The bug affected repeated groups
181        that could potentially match an empty string.
183    37. Optimizing single character iterators in JIT.
185    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
186        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
187        codepoints that are too big for the mode are faulted, and in a UTF mode,
188        disallowed codepoints are also faulted.
190    39. If PCRE was compiled with UTF support, in three places in the DFA
191        matcher there was code that should only have been obeyed in UTF mode, but
192        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
193        processing when bytes with values greater than 127 were present. In 16-bit
194        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
195        both cases the values are those that cannot be the first data item in a UTF
196        character. The three items that might have provoked this were recursions,
197        possessively repeated groups, and atomic groups.
199    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
200        and pcregrep, because some OS require shared objects to be explicitly
201        passed to ld, causing the link step to fail if they are not.
203    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
204        mode, patterns that started with \h* or \R* might be incorrectly matched.
207    Version 8.30 04-February-2012
208    -----------------------------
210    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
211        name is defined in ctype.h.
213    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
214        only in quite long subpatterns.
216    3.  Removed the function pcre_info(), which has been obsolete and deprecated
217        since it was replaced by pcre_fullinfo() in February 2000.
219    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
220        match a (*MARK), and the match failed at the start of the subject, a
221        reference to memory before the start of the subject could occur. This bug
222        was introduced by fix 17 of release 8.21.
224    5.  A reference to an unset group with zero minimum repetition was giving
225        totally wrong answers (in non-JavaScript-compatibility mode). For example,
226        /(another)?(\1?)test/ matched against "hello world test". This bug was
227        introduced in release 8.13.
229    6.  Add support for 16-bit character strings (a large amount of work involving
230        many changes and refactorings).
232    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
233        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
234        from a file.
236    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
237        rounding is not applied in this particular case).
239    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
240        if they appear, or are escaped, in patterns.
242    10. Get rid of a number of -Wunused-but-set-variable warnings.
244    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
245        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
246        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
247        also returns the mark "x". This bug applied to capturing parentheses,
248        non-capturing parentheses, and atomic parentheses. It also applied to some
249        assertions.
251    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
252        information out of configure.ac instead of relying on pcre.h.generic, which
253        is not stored in the repository.
255    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
256        -lreadline.
258    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
260    15. Applied Graycode's patch to put the top-level frame on the stack rather
261        than the heap when not using the stack for recursion. This gives a
262        performance improvement in many cases when recursion is not deep.
264    16. Experimental code added to "pcretest -C" to output the stack frame size.
267    Version 8.21 12-Dec-2011
268    ------------------------
270    1.  Updating the JIT compiler.
272    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
273        are added as well.
275    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
276        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
277        calling _pcre_jit_exec. Some extra comments are added.
279    4.  (*MARK) settings inside atomic groups that do not contain any capturing
280        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
281        was introduced by change 18 for 8.20.
283    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
284        ECMA-262 standard.
286    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
287        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
288        This bug was probably introduced by change 9 of 8.13.
290    7.  While fixing 6 above, I noticed that a number of other items were being
291        incorrectly rejected as "not fixed length". This arose partly because newer
292        opcodes had not been added to the fixed-length checking code. I have (a)
293        corrected the bug and added tests for these items, and (b) arranged for an
294        error to occur if an unknown opcode is encountered while checking for fixed
295        length instead of just assuming "not fixed length". The items that were
296        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
297        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
298        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
300    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
301        being incorrectly compiled and would have given unpredicatble results.
303    9.  A possessively repeated subpattern with minimum repeat count greater than
304        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
305        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
306        the first (A) could occur when it should not.
308    10. Add a cast and remove a redundant test from the code.
310    11. JIT should use pcre_malloc/pcre_free for allocation.
312    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
313        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
314        is anything other than /usr, -L is still shown).
316    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
318    14. Perl does not support \N without a following name in a [] class; PCRE now
319        also gives an error.
321    15. If a forward reference was repeated with an upper limit of around 2000,
322        it caused the error "internal error: overran compiling workspace". The
323        maximum number of forward references (including repeats) was limited by the
324        internal workspace, and dependent on the LINK_SIZE. The code has been
325        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
326        the default depends on LINK_SIZE. There is a new upper limit (for safety)
327        of around 200,000 forward references. While doing this, I also speeded up
328        the filling in of repeated forward references.
330    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
331        incorrectly expecting the subject to contain another "a" after the start.
333    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
334        in the match, the SKIP should be ignored. This was not happening; instead
335        the SKIP was being treated as NOMATCH. For patterns such as
336        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
337        tested.
339    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
340        now much more compatible with Perl, in particular in cases where the result
341        is a non-match for a non-anchored pattern. For example, if
342        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
343        "m", where previously it did not return a name. A side effect of this
344        change is that for partial matches, the last encountered mark name is
345        returned, as for non matches. A number of tests that were previously not
346        Perl-compatible have been moved into the Perl-compatible test files. The
347        refactoring has had the pleasing side effect of removing one argument from
348        the match() function, thus reducing its stack requirements.
350    19. If the /S+ option was used in pcretest to study a pattern using JIT,
351        subsequent uses of /S (without +) incorrectly behaved like /S+.
353    21. Retrieve executable code size support for the JIT compiler and fixing
354        some warnings.
356    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
357        not work when the shorter character appeared right at the end of the
358        subject string.
360    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
361        systems.
363    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
364        output it when the /M option is used in pcretest.
366    25. The CheckMan script was not being included in the distribution. Also, added
367        an explicit "perl" to run Perl scripts from the PrepareRelease script
368        because this is reportedly needed in Windows.
370    26. If study data was being save in a file and studying had not found a set of
371        "starts with" bytes for the pattern, the data written to the file (though
372        never used) was taken from uninitialized memory and so caused valgrind to
373        complain.
375    27. Updated RunTest.bat as provided by Sheri Pierce.
377    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
379    29. Computation of memory usage for the table of capturing group names was
380        giving an unnecessarily large value.
383    Version 8.20 21-Oct-2011
384    ------------------------
386    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
387        a POSIX class. After further experiments with Perl, which convinced me that
388        Perl has bugs and confusions, a closing square bracket is no longer allowed
389        in a POSIX name. This bug also affected patterns with classes that started
390        with full stops.
392    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
393        captured substring, but while checking the failing first alternative,
394        substring 1 is temporarily captured. If the output vector supplied to
395        pcre_exec() was not big enough for this capture, the yield of the function
396        was still zero ("insufficient space for captured substrings"). This cannot
397        be totally fixed without adding another stack variable, which seems a lot
398        of expense for a edge case. However, I have improved the situation in cases
399        such as /(a)(b)x|abc/ matched against "abc", where the return code
400        indicates that fewer than the maximum number of slots in the ovector have
401        been set.
403    3.  Related to (2) above: when there are more back references in a pattern than
404        slots in the output vector, pcre_exec() uses temporary memory during
405        matching, and copies in the captures as far as possible afterwards. It was
406        using the entire output vector, but this conflicts with the specification
407        that only 2/3 is used for passing back captured substrings. Now it uses
408        only the first 2/3, for compatibility. This is, of course, another edge
409        case.
411    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
412        main code base, and can be used by building with --enable-jit. When this is
413        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
414        runtime --no-jit option is given.
416    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
417        ovector, the return from the function was zero, implying that there were
418        other matches that did not fit. The correct "exactly full" value is now
419        returned.
421    6.  If a subpattern that was called recursively or as a subroutine contained
422        (*PRUNE) or any other control that caused it to give a non-standard return,
423        invalid errors such as "Error -26 (nested recursion at the same subject
424        position)" or even infinite loops could occur.
426    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
427        computing the minimum length on reaching *ACCEPT, and so ended up with the
428        wrong value of 1 rather than 0. Further investigation indicates that
429        computing a minimum subject length in the presence of *ACCEPT is difficult
430        (think back references, subroutine calls), and so I have changed the code
431        so that no minimum is registered for a pattern that contains *ACCEPT.
433    8.  If (*THEN) was present in the first (true) branch of a conditional group,
434        it was not handled as intended. [But see 16 below.]
436    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
437        Sheri Pierce.
439    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
440        the first byte in a match must be "a".
442    11. Change 17 for 8.13 increased the recursion depth for patterns like
443        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
444        pattern contains any instances of (*THEN). If it does not, the old
445        optimizations are restored. It would be nice to do this on a per-group
446        basis, but at the moment that is not feasible.
448    12. In some environments, the output of pcretest -C is CRLF terminated. This
449        broke RunTest's code that checks for the link size. A single white space
450        character after the value is now allowed for.
452    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
453        For "fr", it uses the Windows-specific input and output files.
455    14. If (*THEN) appeared in a group that was called recursively or as a
456        subroutine, it did not work as intended. [But see next item.]
458    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
459        pattern fragments (but not containing any | characters). If A and B are
460        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
461        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
462        D. In other words, Perl considers parentheses that do not contain any |
463        characters to be part of a surrounding alternative, whereas PCRE was
464        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
465        differently. PCRE now behaves in the same way as Perl, except in the case
466        of subroutine/recursion calls such as (?1) which have in any case always
467        been different (but PCRE had them first :-).
469    16. Related to 15 above: Perl does not treat the | in a conditional group as
470        creating alternatives. Such a group is treated in the same way as an
471        ordinary group without any | characters when processing (*THEN). PCRE has
472        been changed to match Perl's behaviour.
474    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
475        RunGrepTest script failed.
477    18. Change 22 for version 13 caused atomic groups to use more stack. This is
478        inevitable for groups that contain captures, but it can lead to a lot of
479        stack use in large patterns. The old behaviour has been restored for atomic
480        groups that do not contain any capturing parentheses.
482    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
483        suppress the check for a minimum subject length at run time. (If it was
484        given to pcre_exec() or pcre_dfa_exec() it did work.)
486    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
487        fail to work when decoding hex characters in data strings in EBCDIC
488        environments.
490    21. It appears that in at least one Mac OS environment, the isxdigit() function
491        is implemented as a macro that evaluates to its argument more than once,
492        contravening the C 90 Standard (I haven't checked a later standard). There
493        was an instance in pcretest which caused it to go wrong when processing
494        \x{...} escapes in subject strings. The has been rewritten to avoid using
495        things like p++ in the argument of isxdigit().
498    Version 8.13 16-Aug-2011
499    ------------------------
501    1.  The Unicode data tables have been updated to Unicode 6.0.0.
503    2.  Two minor typos in pcre_internal.h have been fixed.
505    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
506        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
507        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
509    4.  There were a number of related bugs in the code for matching backrefences
510        caselessly in UTF-8 mode when codes for the characters concerned were
511        different numbers of bytes. For example, U+023A and U+2C65 are an upper
512        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
513        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
514        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
515        2-byte code at the end of the subject (it thought there wasn't enough data
516        left).
518    5.  Comprehensive information about what went wrong is now returned by
519        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
520        as the output vector has at least 2 elements. The offset of the start of
521        the failing character and a reason code are placed in the vector.
523    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
524        now returned is for the first byte of the failing character, instead of the
525        last byte inspected. This is an incompatible change, but I hope it is small
526        enough not to be a problem. It makes the returned offset consistent with
527        pcre_exec() and pcre_dfa_exec().
529    7.  pcretest now gives a text phrase as well as the error number when
530        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
531        failure, the offset and reason code are output.
533    8.  When \R was used with a maximizing quantifier it failed to skip backwards
534        over a \r\n pair if the subsequent match failed. Instead, it just skipped
535        back over a single character (\n). This seems wrong (because it treated the
536        two characters as a single entity when going forwards), conflicts with the
537        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
538        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
539        has been changed.
541    9.  Some internal refactoring has changed the processing so that the handling
542        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
543        time (the PCRE_DOTALL option was changed this way some time ago: version
544        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
545        which was always a bit of a fudge. It also means that there is one less
546        argument for the match() function, which reduces its stack requirements
547        slightly. This change also fixes an incompatibility with Perl: the pattern
548        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
550    10. More internal refactoring has drastically reduced the number of recursive
551        calls to match() for possessively repeated groups such as (abc)++ when
552        using pcre_exec().
554    11. While implementing 10, a number of bugs in the handling of groups were
555        discovered and fixed:
557        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
558        (a|)*(?1) gave a compile-time internal error.
559        ((a|)+)+  did not notice that the outer group could match an empty string.
560        (^a|^)+   was not marked as anchored.
561        (.*a|.*)+ was not marked as matching at start or after a newline.
563    12. Yet more internal refactoring has removed another argument from the match()
564        function. Special calls to this function are now indicated by setting a
565        value in a variable in the "match data" data block.
567    13. Be more explicit in pcre_study() instead of relying on "default" for
568        opcodes that mean there is no starting character; this means that when new
569        ones are added and accidentally left out of pcre_study(), testing should
570        pick them up.
572    14. The -s option of pcretest has been documented for ages as being an old
573        synonym of -m (show memory usage). I have changed it to mean "force study
574        for every regex", that is, assume /S for every regex. This is similar to -i
575        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
576        using it. It makes it easier to run collections of tests with and without
577        study enabled, and thereby test pcre_study() more easily. All the standard
578        tests are now run with and without -s (but some patterns can be marked as
579        "never study" - see 20 below).
581    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
582        restoration of the capturing data to the outer values was not happening
583        correctly.
585    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
586        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
587        pattern had matched an empty string, and so incorrectly returned a no
588        match.
590    17. There was optimizing code for the last branch of non-capturing parentheses,
591        and also for the obeyed branch of a conditional subexpression, which used
592        tail recursion to cut down on stack usage. Unfortunately, now that there is
593        the possibility of (*THEN) occurring in these branches, tail recursion is
594        no longer possible because the return has to be checked for (*THEN). These
595        two optimizations have therefore been removed. [But see 8.20/11 above.]
597    18. If a pattern containing \R was studied, it was assumed that \R always
598        matched two bytes, thus causing the minimum subject length to be
599        incorrectly computed because \R can also match just one byte.
601    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
602        was incorrectly computed.
604    20. If /S is present twice on a test pattern in pcretest input, it now
605        *disables* studying, thereby overriding the use of -s on the command line
606        (see 14 above). This is necessary for one or two tests to keep the output
607        identical in both cases.
609    21. When (*ACCEPT) was used in an assertion that matched an empty string and
610        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
612    22. When an atomic group that contained a capturing parenthesis was
613        successfully matched, but the branch in which it appeared failed, the
614        capturing was not being forgotten if a higher numbered group was later
615        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
616        group 1 to "a", when in fact it should be unset. This applied to multi-
617        branched capturing and non-capturing groups, repeated or not, and also to
618        positive assertions (capturing in negative assertions does not happen
619        in PCRE) and also to nested atomic groups.
621    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
622        subject after a captured substring, to make it easier to tell which of a
623        number of identical substrings has been captured.
625    24. The way atomic groups are processed by pcre_exec() has been changed so that
626        if they are repeated, backtracking one repetition now resets captured
627        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
628        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
629        "aaa". Previously, it would have been "a". As part of this code
630        refactoring, the way recursive calls are handled has also been changed.
632    25. If an assertion condition captured any substrings, they were not passed
633        back unless some other capturing happened later. For example, if
634        (?(?=(a))a) was matched against "a", no capturing was returned.
636    26. When studying a pattern that contained subroutine calls or assertions,
637        the code for finding the minimum length of a possible match was handling
638        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
639        group 1 called group 2 while simultaneously a separate group 2 called group
640        1). A stack overflow occurred in this case. I have fixed this by limiting
641        the recursion depth to 10.
643    27. Updated RunTest.bat in the distribution to the version supplied by Tom
644        Fortmann. This supports explicit test numbers on the command line, and has
645        argument validation and error reporting.
647    28. An instance of \X with an unlimited repeat could fail if at any point the
648        first character it looked at was a mark character.
650    29. Some minor code refactoring concerning Unicode properties and scripts
651        should reduce the stack requirement of match() slightly.
653    30. Added the '=' option to pcretest to check the setting of unused capturing
654        slots at the end of the pattern, which are documented as being -1, but are
655        not included in the return count.
657    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
658        compiled something random. Now it gives a compile-time error (as does
659        Perl).
661    32. A *MARK encountered during the processing of a positive assertion is now
662        recorded and passed back (compatible with Perl).
664    33. If --only-matching or --colour was set on a pcregrep call whose pattern
665        had alternative anchored branches, the search for a second match in a line
666        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
667        matched the line "0102" twice. The same bug affected patterns that started
668        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
669        twice.
671    34. Previously, PCRE did not allow quantification of assertions. However, Perl
672        does, and because of capturing effects, quantifying parenthesized
673        assertions may at times be useful. Quantifiers are now allowed for
674        parenthesized assertions.
676    35. A minor code tidy in pcre_compile() when checking options for \R usage.
678    36. \g was being checked for fancy things in a character class, when it should
679        just be a literal "g".
681    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
682        appearance of a nested POSIX class supersedes an apparent external class.
683        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
684        unescaped square brackets may also appear as part of class names. For
685        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
686        more like Perl. (But see 8.20/1 above.)
688    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
689        was because it thought it was \N{name}, which is not supported).
691    39. Add minix to OS list not supporting the -S option in pcretest.
693    40. PCRE tries to detect cases of infinite recursion at compile time, but it
694        cannot analyze patterns in sufficient detail to catch mutual recursions
695        such as ((?1))((?2)). There is now a runtime test that gives an error if a
696        subgroup is called recursively as a subpattern for a second time at the
697        same position in the subject string. In previous releases this might have
698        been caught by the recursion limit, or it might have run out of stack.
700    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
701        happen only once. PCRE was, however incorrectly giving a compile time error
702        "recursive call could loop indefinitely" because it cannot analyze the
703        pattern in sufficient detail. The compile time test no longer happens when
704        PCRE is compiling a conditional subpattern, but actual runaway loops are
705        now caught at runtime (see 40 above).
707    42. It seems that Perl allows any characters other than a closing parenthesis
708        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
709        has been changed to be the same.
711    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
712        as not to get warnings when autogen.sh is called. Also changed
713        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
715    44. To help people who use pcregrep to scan files containing exceedingly long
716        lines, the following changes have been made:
718        (a) The default value of the buffer size parameter has been increased from
719            8K to 20K. (The actual buffer used is three times this size.)
721        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
722            PCRE is built.
724        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
725            to be set at run time.
727        (d) Numerical values in pcregrep options can be followed by K or M, for
728            example --buffer-size=50K.
730        (e) If a line being scanned overflows pcregrep's buffer, an error is now
731            given and the return code is set to 2.
733    45. Add a pointer to the latest mark to the callout data block.
735    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
736        partial match of an empty string instead of no match. This was specific to
737        the use of ".".
739    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
740        complete match instead of a partial match. This bug was dependent on both
741        the PCRE_UTF8 and PCRE_DOTALL options being set.
743    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
744        starting byte set, because \b was not being ignored.
747    Version 8.12 15-Jan-2011
748    ------------------------
750    1.  Fixed some typos in the markup of the man pages, and wrote a script that
751        checks for such things as part of the documentation building process.
753    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
754        --match-limit and --recursion-limit options (added for 8.11). In
755        particular, this made one of the standard tests fail. (The integer value
756        went into the wrong half of a long int.)
758    3.  If the --colour option was given to pcregrep with -v (invert match), it
759        did strange things, either producing crazy output, or crashing. It should,
760        of course, ignore a request for colour when reporting lines that do not
761        match.
763    4.  Another pcregrep bug caused similar problems if --colour was specified with
764        -M (multiline) and the pattern match finished with a line ending.
766    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
767        matched in multiline mode, the following line was shown as part of the
768        match. This seems wrong, so I have changed it.
770    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
771        the check for further matches in the same line (so they could be coloured)
772        to overrun the end of the current line. If another match was found, it was
773        incorrectly shown (and then shown again when found in the next line).
775    7.  If pcregrep was compiled under Windows, there was a reference to the
776        function pcregrep_exit() before it was defined. I am assuming this was
777        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
778        reported by a user. I've moved the definition above the reference.
781    Version 8.11 10-Dec-2010
782    ------------------------
784    1.  (*THEN) was not working properly if there were untried alternatives prior
785        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
786        backtracked to try for "b" instead of moving to the next alternative branch
787        at the same level (in this case, to look for "c"). The Perl documentation
788        is clear that when (*THEN) is backtracked onto, it goes to the "next
789        alternative in the innermost enclosing group".
791    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
792        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
793        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
794        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
795        (*THEN).
797    3.  If \s appeared in a character class, it removed the VT character from
798        the class, even if it had been included by some previous item, for example
799        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
800        of \s, but is part of the POSIX "space" class.)
802    4.  A partial match never returns an empty string (because you can always
803        match an empty string at the end of the subject); however the checking for
804        an empty string was starting at the "start of match" point. This has been
805        changed to the "earliest inspected character" point, because the returned
806        data for a partial match starts at this character. This means that, for
807        example, /(?<=abc)def/ gives a partial match for the subject "abc"
808        (previously it gave "no match").
810    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
811        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
812        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
813        has an implication that the given string is incomplete (because a partial
814        match is preferred over a full match). For this reason, these items now
815        give a partial match in this situation. [Aside: previously, the one case
816        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
817        match rather than a full match, which was wrong by the old rules, but is
818        now correct.]
820    6.  There was a bug in the handling of #-introduced comments, recognized when
821        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
822        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
823        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
824        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
825        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
826        places in pcre_compile().
828    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
829        comments when looking ahead for named forward references to subpatterns,
830        the only newline sequence it recognized was NL. It now handles newlines
831        according to the set newline convention.
833    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
834        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
835        cater for a lack of strerror(). These oversights have been fixed.
837    9.  Added --match-limit and --recursion-limit to pcregrep.
839    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
841    11. When the -o option was used, pcregrep was setting a return code of 1, even
842        when matches were found, and --line-buffered was not being honoured.
844    12. Added an optional parentheses number to the -o and --only-matching options
845        of pcregrep.
847    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
848        can match an empty string. The code to do it in pcretest and pcredemo
849        needed fixing:
851        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
852            only one byte after an empty string match just before CRLF (this case
853            just got forgotten; "any" and "anycrlf" were OK).
855        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
856            mode when an empty string match preceded an ASCII character followed by
857            a non-ASCII character. (The code for advancing by one character rather
858            than one byte was nonsense.)
860        (c) The pcredemo.c sample program did not have any code at all to handle
861            the cases when CRLF is a valid newline sequence.
863    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
864        as a starting offset was within the subject string. There is now a new
865        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
866        negative or greater than the length of the string. In order to test this,
867        pcretest is extended to allow the setting of negative starting offsets.
869    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
870        starting offset points to the beginning of a UTF-8 character was
871        unnecessarily clumsy. I tidied it up.
873    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
874        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
876    17. Nobody had reported that the --include_dir option, which was added in
877        release 7.7 should have been called --include-dir (hyphen, not underscore)
878        for compatibility with GNU grep. I have changed it to --include-dir, but
879        left --include_dir as an undocumented synonym, and the same for
880        --exclude-dir, though that is not available in GNU grep, at least as of
881        release 2.5.4.
883    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
884        characters from a string of bytes) have been redefined so as not to use
885        loops, in order to improve performance in some environments. At the same
886        time, I abstracted some of the common code into auxiliary macros to save
887        repetition (this should not affect the compiled code).
889    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
890        compile-time error is now given if \c is not followed by an ASCII
891        character, that is, a byte less than 128. (In EBCDIC mode, the code is
892        different, and any byte value is allowed.)
894    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
895        START_OPTIMIZE option, which is now allowed at compile time - but just
896        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
897        to pcregrep and other applications that have no direct access to PCRE
898        options. The new /Y option in pcretest sets this option when calling
899        pcre_compile().
901    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
902        back references. Groups containing recursive back references were forced to
903        be atomic by that change, but in the case of named groups, the amount of
904        memory required was incorrectly computed, leading to "Failed: internal
905        error: code overflow". This has been fixed.
907    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
908        pcretest.c, to avoid build problems in some Borland environments.
911    Version 8.10 25-Jun-2010
912  ------------------------  ------------------------
914  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and

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