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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.02 01-Mar-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.
53    10. Changed the meaning of \X in the interpreters so that it now matches a
54        Unicode extended grapheme cluster.
58    Version 8.31 06-July-2012
59    -------------------------
61    1.  Fixing a wrong JIT test case and some compiler warnings.
63    2.  Removed a bashism from the RunTest script.
65    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
66        to unsigned type, result still unsigned" that was given by an MS compiler
67        on encountering the code "-sizeof(xxx)".
69    4.  Partial matching support is added to the JIT compiler.
71    5.  Fixed several bugs concerned with partial matching of items that consist
72        of more than one character:
74        (a) /^(..)\1/ did not partially match "aba" because checking references was
75            done on an "all or nothing" basis. This also applied to repeated
76            references.
78        (b) \R did not give a hard partial match if \r was found at the end of the
79            subject.
81        (c) \X did not give a hard partial match after matching one or more
82            characters at the end of the subject.
84        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
85            a partial match for the string "\r".
87        (e) When newline was set to CRLF, the metacharacter "." did not recognize
88            a partial match for a CR character at the end of the subject string.
90    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
91        running pcretest, the text "(JIT)" added to the output whenever JIT is
92        actually used to run the match.
94    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
95        or /S+[+] with a digit between 1 and 7.
97    8.  OP_NOT now supports any UTF character not just single-byte ones.
99    9.  (*MARK) control verb is now supported by the JIT compiler.
101    10. The command "./RunTest list" lists the available tests without actually
102        running any of them. (Because I keep forgetting what they all are.)
106    12. Applied a (slightly modified) user-supplied patch that improves performance
107        when the heap is used for recursion (compiled with --disable-stack-for-
108        recursion). Instead of malloc and free for each heap frame each time a
109        logical recursion happens, frames are retained on a chain and re-used where
110        possible. This sometimes gives as much as 30% improvement.
112    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
113        call.
115    14. As documented, (*COMMIT) is now confined to within a positive assertion.
117    15. It is now possible to link pcretest with libedit as an alternative to
118        libreadline.
120    16. (*COMMIT) control verb is now supported by the JIT compiler.
122    17. The Unicode data tables have been updated to Unicode 6.1.0.
124    18. Added --file-list option to pcregrep.
126    19. Added binary file support to pcregrep, including the -a, --binary-files,
127        -I, and --text options.
129    20. The madvise function is renamed for posix_madvise for QNX compatibility
130        reasons. Fixed by Giuseppe D'Angelo.
132    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
134    22. Changed the option for creating symbolic links for 16-bit man pages from
135        -s to -sf so that re-installing does not cause issues.
137    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
139    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
140        matches in certain environments (the workspace was not being correctly
141        retained). Also added to pcre_dfa_exec() a simple plausibility check on
142        some of the workspace data at the beginning of a restart.
144    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
145        was not doing so when it should - probably a typo introduced by SVN 528
146        (change 8.10/14).
148    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
149        \w+ when the character tables indicated that \x{c4} was a word character.
150        There were several related cases, all because the tests for doing a table
151        lookup were testing for characters less than 127 instead of 255.
153    27. If a pattern contains capturing parentheses that are not used in a match,
154        their slots in the ovector are set to -1. For those that are higher than
155        any matched groups, this happens at the end of processing. In the case when
156        there were back references that the ovector was too small to contain
157        (causing temporary malloc'd memory to be used during matching), and the
158        highest capturing number was not used, memory off the end of the ovector
159        was incorrectly being set to -1. (It was using the size of the temporary
160        memory instead of the true size.)
162    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
163        ovector size, it uses memory at the end of the block that it has got.
165    29. Check for an overlong MARK name and give an error at compile time. The
166        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
168    30. JIT compiler update.
170    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
171        Rill for the patch.
173    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
175    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
177    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
178        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
179        was enabled.
181    35. Improve JIT code generation for greedy plus quantifier.
183    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
184        1 to "aa" instead of to an empty string. The bug affected repeated groups
185        that could potentially match an empty string.
187    37. Optimizing single character iterators in JIT.
189    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
190        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
191        codepoints that are too big for the mode are faulted, and in a UTF mode,
192        disallowed codepoints are also faulted.
194    39. If PCRE was compiled with UTF support, in three places in the DFA
195        matcher there was code that should only have been obeyed in UTF mode, but
196        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
197        processing when bytes with values greater than 127 were present. In 16-bit
198        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
199        both cases the values are those that cannot be the first data item in a UTF
200        character. The three items that might have provoked this were recursions,
201        possessively repeated groups, and atomic groups.
203    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
204        and pcregrep, because some OS require shared objects to be explicitly
205        passed to ld, causing the link step to fail if they are not.
207    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
208        mode, patterns that started with \h* or \R* might be incorrectly matched.
211    Version 8.30 04-February-2012
212    -----------------------------
214    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
215        name is defined in ctype.h.
217    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
218        only in quite long subpatterns.
220    3.  Removed the function pcre_info(), which has been obsolete and deprecated
221        since it was replaced by pcre_fullinfo() in February 2000.
223    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
224        match a (*MARK), and the match failed at the start of the subject, a
225        reference to memory before the start of the subject could occur. This bug
226        was introduced by fix 17 of release 8.21.
228    5.  A reference to an unset group with zero minimum repetition was giving
229        totally wrong answers (in non-JavaScript-compatibility mode). For example,
230        /(another)?(\1?)test/ matched against "hello world test". This bug was
231        introduced in release 8.13.
233    6.  Add support for 16-bit character strings (a large amount of work involving
234        many changes and refactorings).
236    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
237        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
238        from a file.
240    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
241        rounding is not applied in this particular case).
243    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
244        if they appear, or are escaped, in patterns.
246    10. Get rid of a number of -Wunused-but-set-variable warnings.
248    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
249        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
250        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
251        also returns the mark "x". This bug applied to capturing parentheses,
252        non-capturing parentheses, and atomic parentheses. It also applied to some
253        assertions.
255    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
256        information out of configure.ac instead of relying on pcre.h.generic, which
257        is not stored in the repository.
259    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
260        -lreadline.
262    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
264    15. Applied Graycode's patch to put the top-level frame on the stack rather
265        than the heap when not using the stack for recursion. This gives a
266        performance improvement in many cases when recursion is not deep.
268    16. Experimental code added to "pcretest -C" to output the stack frame size.
271    Version 8.21 12-Dec-2011
272    ------------------------
274    1.  Updating the JIT compiler.
276    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
277        are added as well.
279    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
280        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
281        calling _pcre_jit_exec. Some extra comments are added.
283    4.  (*MARK) settings inside atomic groups that do not contain any capturing
284        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
285        was introduced by change 18 for 8.20.
287    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
288        ECMA-262 standard.
290    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
291        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
292        This bug was probably introduced by change 9 of 8.13.
294    7.  While fixing 6 above, I noticed that a number of other items were being
295        incorrectly rejected as "not fixed length". This arose partly because newer
296        opcodes had not been added to the fixed-length checking code. I have (a)
297        corrected the bug and added tests for these items, and (b) arranged for an
298        error to occur if an unknown opcode is encountered while checking for fixed
299        length instead of just assuming "not fixed length". The items that were
300        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
301        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
302        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
304    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
305        being incorrectly compiled and would have given unpredicatble results.
307    9.  A possessively repeated subpattern with minimum repeat count greater than
308        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
309        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
310        the first (A) could occur when it should not.
312    10. Add a cast and remove a redundant test from the code.
314    11. JIT should use pcre_malloc/pcre_free for allocation.
316    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
317        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
318        is anything other than /usr, -L is still shown).
320    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
322    14. Perl does not support \N without a following name in a [] class; PCRE now
323        also gives an error.
325    15. If a forward reference was repeated with an upper limit of around 2000,
326        it caused the error "internal error: overran compiling workspace". The
327        maximum number of forward references (including repeats) was limited by the
328        internal workspace, and dependent on the LINK_SIZE. The code has been
329        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
330        the default depends on LINK_SIZE. There is a new upper limit (for safety)
331        of around 200,000 forward references. While doing this, I also speeded up
332        the filling in of repeated forward references.
334    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
335        incorrectly expecting the subject to contain another "a" after the start.
337    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
338        in the match, the SKIP should be ignored. This was not happening; instead
339        the SKIP was being treated as NOMATCH. For patterns such as
340        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
341        tested.
343    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
344        now much more compatible with Perl, in particular in cases where the result
345        is a non-match for a non-anchored pattern. For example, if
346        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
347        "m", where previously it did not return a name. A side effect of this
348        change is that for partial matches, the last encountered mark name is
349        returned, as for non matches. A number of tests that were previously not
350        Perl-compatible have been moved into the Perl-compatible test files. The
351        refactoring has had the pleasing side effect of removing one argument from
352        the match() function, thus reducing its stack requirements.
354    19. If the /S+ option was used in pcretest to study a pattern using JIT,
355        subsequent uses of /S (without +) incorrectly behaved like /S+.
357    21. Retrieve executable code size support for the JIT compiler and fixing
358        some warnings.
360    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
361        not work when the shorter character appeared right at the end of the
362        subject string.
364    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
365        systems.
367    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
368        output it when the /M option is used in pcretest.
370    25. The CheckMan script was not being included in the distribution. Also, added
371        an explicit "perl" to run Perl scripts from the PrepareRelease script
372        because this is reportedly needed in Windows.
374    26. If study data was being save in a file and studying had not found a set of
375        "starts with" bytes for the pattern, the data written to the file (though
376        never used) was taken from uninitialized memory and so caused valgrind to
377        complain.
379    27. Updated RunTest.bat as provided by Sheri Pierce.
381    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
383    29. Computation of memory usage for the table of capturing group names was
384        giving an unnecessarily large value.
387    Version 8.20 21-Oct-2011
388    ------------------------
390    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
391        a POSIX class. After further experiments with Perl, which convinced me that
392        Perl has bugs and confusions, a closing square bracket is no longer allowed
393        in a POSIX name. This bug also affected patterns with classes that started
394        with full stops.
396    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
397        captured substring, but while checking the failing first alternative,
398        substring 1 is temporarily captured. If the output vector supplied to
399        pcre_exec() was not big enough for this capture, the yield of the function
400        was still zero ("insufficient space for captured substrings"). This cannot
401        be totally fixed without adding another stack variable, which seems a lot
402        of expense for a edge case. However, I have improved the situation in cases
403        such as /(a)(b)x|abc/ matched against "abc", where the return code
404        indicates that fewer than the maximum number of slots in the ovector have
405        been set.
407    3.  Related to (2) above: when there are more back references in a pattern than
408        slots in the output vector, pcre_exec() uses temporary memory during
409        matching, and copies in the captures as far as possible afterwards. It was
410        using the entire output vector, but this conflicts with the specification
411        that only 2/3 is used for passing back captured substrings. Now it uses
412        only the first 2/3, for compatibility. This is, of course, another edge
413        case.
415    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
416        main code base, and can be used by building with --enable-jit. When this is
417        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
418        runtime --no-jit option is given.
420    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
421        ovector, the return from the function was zero, implying that there were
422        other matches that did not fit. The correct "exactly full" value is now
423        returned.
425    6.  If a subpattern that was called recursively or as a subroutine contained
426        (*PRUNE) or any other control that caused it to give a non-standard return,
427        invalid errors such as "Error -26 (nested recursion at the same subject
428        position)" or even infinite loops could occur.
430    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
431        computing the minimum length on reaching *ACCEPT, and so ended up with the
432        wrong value of 1 rather than 0. Further investigation indicates that
433        computing a minimum subject length in the presence of *ACCEPT is difficult
434        (think back references, subroutine calls), and so I have changed the code
435        so that no minimum is registered for a pattern that contains *ACCEPT.
437    8.  If (*THEN) was present in the first (true) branch of a conditional group,
438        it was not handled as intended. [But see 16 below.]
440    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
441        Sheri Pierce.
443    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
444        the first byte in a match must be "a".
446    11. Change 17 for 8.13 increased the recursion depth for patterns like
447        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
448        pattern contains any instances of (*THEN). If it does not, the old
449        optimizations are restored. It would be nice to do this on a per-group
450        basis, but at the moment that is not feasible.
452    12. In some environments, the output of pcretest -C is CRLF terminated. This
453        broke RunTest's code that checks for the link size. A single white space
454        character after the value is now allowed for.
456    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
457        For "fr", it uses the Windows-specific input and output files.
459    14. If (*THEN) appeared in a group that was called recursively or as a
460        subroutine, it did not work as intended. [But see next item.]
462    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
463        pattern fragments (but not containing any | characters). If A and B are
464        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
465        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
466        D. In other words, Perl considers parentheses that do not contain any |
467        characters to be part of a surrounding alternative, whereas PCRE was
468        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
469        differently. PCRE now behaves in the same way as Perl, except in the case
470        of subroutine/recursion calls such as (?1) which have in any case always
471        been different (but PCRE had them first :-).
473    16. Related to 15 above: Perl does not treat the | in a conditional group as
474        creating alternatives. Such a group is treated in the same way as an
475        ordinary group without any | characters when processing (*THEN). PCRE has
476        been changed to match Perl's behaviour.
478    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
479        RunGrepTest script failed.
481    18. Change 22 for version 13 caused atomic groups to use more stack. This is
482        inevitable for groups that contain captures, but it can lead to a lot of
483        stack use in large patterns. The old behaviour has been restored for atomic
484        groups that do not contain any capturing parentheses.
486    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
487        suppress the check for a minimum subject length at run time. (If it was
488        given to pcre_exec() or pcre_dfa_exec() it did work.)
490    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
491        fail to work when decoding hex characters in data strings in EBCDIC
492        environments.
494    21. It appears that in at least one Mac OS environment, the isxdigit() function
495        is implemented as a macro that evaluates to its argument more than once,
496        contravening the C 90 Standard (I haven't checked a later standard). There
497        was an instance in pcretest which caused it to go wrong when processing
498        \x{...} escapes in subject strings. The has been rewritten to avoid using
499        things like p++ in the argument of isxdigit().
502    Version 8.13 16-Aug-2011
503    ------------------------
505    1.  The Unicode data tables have been updated to Unicode 6.0.0.
507    2.  Two minor typos in pcre_internal.h have been fixed.
509    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
510        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
511        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
513    4.  There were a number of related bugs in the code for matching backrefences
514        caselessly in UTF-8 mode when codes for the characters concerned were
515        different numbers of bytes. For example, U+023A and U+2C65 are an upper
516        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
517        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
518        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
519        2-byte code at the end of the subject (it thought there wasn't enough data
520        left).
522    5.  Comprehensive information about what went wrong is now returned by
523        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
524        as the output vector has at least 2 elements. The offset of the start of
525        the failing character and a reason code are placed in the vector.
527    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
528        now returned is for the first byte of the failing character, instead of the
529        last byte inspected. This is an incompatible change, but I hope it is small
530        enough not to be a problem. It makes the returned offset consistent with
531        pcre_exec() and pcre_dfa_exec().
533    7.  pcretest now gives a text phrase as well as the error number when
534        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
535        failure, the offset and reason code are output.
537    8.  When \R was used with a maximizing quantifier it failed to skip backwards
538        over a \r\n pair if the subsequent match failed. Instead, it just skipped
539        back over a single character (\n). This seems wrong (because it treated the
540        two characters as a single entity when going forwards), conflicts with the
541        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
542        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
543        has been changed.
545    9.  Some internal refactoring has changed the processing so that the handling
546        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
547        time (the PCRE_DOTALL option was changed this way some time ago: version
548        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
549        which was always a bit of a fudge. It also means that there is one less
550        argument for the match() function, which reduces its stack requirements
551        slightly. This change also fixes an incompatibility with Perl: the pattern
552        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
554    10. More internal refactoring has drastically reduced the number of recursive
555        calls to match() for possessively repeated groups such as (abc)++ when
556        using pcre_exec().
558    11. While implementing 10, a number of bugs in the handling of groups were
559        discovered and fixed:
561        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
562        (a|)*(?1) gave a compile-time internal error.
563        ((a|)+)+  did not notice that the outer group could match an empty string.
564        (^a|^)+   was not marked as anchored.
565        (.*a|.*)+ was not marked as matching at start or after a newline.
567    12. Yet more internal refactoring has removed another argument from the match()
568        function. Special calls to this function are now indicated by setting a
569        value in a variable in the "match data" data block.
571    13. Be more explicit in pcre_study() instead of relying on "default" for
572        opcodes that mean there is no starting character; this means that when new
573        ones are added and accidentally left out of pcre_study(), testing should
574        pick them up.
576    14. The -s option of pcretest has been documented for ages as being an old
577        synonym of -m (show memory usage). I have changed it to mean "force study
578        for every regex", that is, assume /S for every regex. This is similar to -i
579        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
580        using it. It makes it easier to run collections of tests with and without
581        study enabled, and thereby test pcre_study() more easily. All the standard
582        tests are now run with and without -s (but some patterns can be marked as
583        "never study" - see 20 below).
585    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
586        restoration of the capturing data to the outer values was not happening
587        correctly.
589    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
590        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
591        pattern had matched an empty string, and so incorrectly returned a no
592        match.
594    17. There was optimizing code for the last branch of non-capturing parentheses,
595        and also for the obeyed branch of a conditional subexpression, which used
596        tail recursion to cut down on stack usage. Unfortunately, now that there is
597        the possibility of (*THEN) occurring in these branches, tail recursion is
598        no longer possible because the return has to be checked for (*THEN). These
599        two optimizations have therefore been removed. [But see 8.20/11 above.]
601    18. If a pattern containing \R was studied, it was assumed that \R always
602        matched two bytes, thus causing the minimum subject length to be
603        incorrectly computed because \R can also match just one byte.
605    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
606        was incorrectly computed.
608    20. If /S is present twice on a test pattern in pcretest input, it now
609        *disables* studying, thereby overriding the use of -s on the command line
610        (see 14 above). This is necessary for one or two tests to keep the output
611        identical in both cases.
613    21. When (*ACCEPT) was used in an assertion that matched an empty string and
614        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
616    22. When an atomic group that contained a capturing parenthesis was
617        successfully matched, but the branch in which it appeared failed, the
618        capturing was not being forgotten if a higher numbered group was later
619        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
620        group 1 to "a", when in fact it should be unset. This applied to multi-
621        branched capturing and non-capturing groups, repeated or not, and also to
622        positive assertions (capturing in negative assertions does not happen
623        in PCRE) and also to nested atomic groups.
625    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
626        subject after a captured substring, to make it easier to tell which of a
627        number of identical substrings has been captured.
629    24. The way atomic groups are processed by pcre_exec() has been changed so that
630        if they are repeated, backtracking one repetition now resets captured
631        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
632        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
633        "aaa". Previously, it would have been "a". As part of this code
634        refactoring, the way recursive calls are handled has also been changed.
636    25. If an assertion condition captured any substrings, they were not passed
637        back unless some other capturing happened later. For example, if
638        (?(?=(a))a) was matched against "a", no capturing was returned.
640    26. When studying a pattern that contained subroutine calls or assertions,
641        the code for finding the minimum length of a possible match was handling
642        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
643        group 1 called group 2 while simultaneously a separate group 2 called group
644        1). A stack overflow occurred in this case. I have fixed this by limiting
645        the recursion depth to 10.
647    27. Updated RunTest.bat in the distribution to the version supplied by Tom
648        Fortmann. This supports explicit test numbers on the command line, and has
649        argument validation and error reporting.
651    28. An instance of \X with an unlimited repeat could fail if at any point the
652        first character it looked at was a mark character.
654    29. Some minor code refactoring concerning Unicode properties and scripts
655        should reduce the stack requirement of match() slightly.
657    30. Added the '=' option to pcretest to check the setting of unused capturing
658        slots at the end of the pattern, which are documented as being -1, but are
659        not included in the return count.
661    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
662        compiled something random. Now it gives a compile-time error (as does
663        Perl).
665    32. A *MARK encountered during the processing of a positive assertion is now
666        recorded and passed back (compatible with Perl).
668    33. If --only-matching or --colour was set on a pcregrep call whose pattern
669        had alternative anchored branches, the search for a second match in a line
670        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
671        matched the line "0102" twice. The same bug affected patterns that started
672        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
673        twice.
675    34. Previously, PCRE did not allow quantification of assertions. However, Perl
676        does, and because of capturing effects, quantifying parenthesized
677        assertions may at times be useful. Quantifiers are now allowed for
678        parenthesized assertions.
680    35. A minor code tidy in pcre_compile() when checking options for \R usage.
682    36. \g was being checked for fancy things in a character class, when it should
683        just be a literal "g".
685    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
686        appearance of a nested POSIX class supersedes an apparent external class.
687        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
688        unescaped square brackets may also appear as part of class names. For
689        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
690        more like Perl. (But see 8.20/1 above.)
692    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
693        was because it thought it was \N{name}, which is not supported).
695    39. Add minix to OS list not supporting the -S option in pcretest.
697    40. PCRE tries to detect cases of infinite recursion at compile time, but it
698        cannot analyze patterns in sufficient detail to catch mutual recursions
699        such as ((?1))((?2)). There is now a runtime test that gives an error if a
700        subgroup is called recursively as a subpattern for a second time at the
701        same position in the subject string. In previous releases this might have
702        been caught by the recursion limit, or it might have run out of stack.
704    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
705        happen only once. PCRE was, however incorrectly giving a compile time error
706        "recursive call could loop indefinitely" because it cannot analyze the
707        pattern in sufficient detail. The compile time test no longer happens when
708        PCRE is compiling a conditional subpattern, but actual runaway loops are
709        now caught at runtime (see 40 above).
711    42. It seems that Perl allows any characters other than a closing parenthesis
712        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
713        has been changed to be the same.
715    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
716        as not to get warnings when autogen.sh is called. Also changed
717        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
719    44. To help people who use pcregrep to scan files containing exceedingly long
720        lines, the following changes have been made:
722        (a) The default value of the buffer size parameter has been increased from
723            8K to 20K. (The actual buffer used is three times this size.)
725        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
726            PCRE is built.
728        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
729            to be set at run time.
731        (d) Numerical values in pcregrep options can be followed by K or M, for
732            example --buffer-size=50K.
734        (e) If a line being scanned overflows pcregrep's buffer, an error is now
735            given and the return code is set to 2.
737    45. Add a pointer to the latest mark to the callout data block.
739    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
740        partial match of an empty string instead of no match. This was specific to
741        the use of ".".
743    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
744        complete match instead of a partial match. This bug was dependent on both
745        the PCRE_UTF8 and PCRE_DOTALL options being set.
747    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
748        starting byte set, because \b was not being ignored.
751    Version 8.12 15-Jan-2011
752    ------------------------
754    1.  Fixed some typos in the markup of the man pages, and wrote a script that
755        checks for such things as part of the documentation building process.
757    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
758        --match-limit and --recursion-limit options (added for 8.11). In
759        particular, this made one of the standard tests fail. (The integer value
760        went into the wrong half of a long int.)
762    3.  If the --colour option was given to pcregrep with -v (invert match), it
763        did strange things, either producing crazy output, or crashing. It should,
764        of course, ignore a request for colour when reporting lines that do not
765        match.
767    4.  Another pcregrep bug caused similar problems if --colour was specified with
768        -M (multiline) and the pattern match finished with a line ending.
770    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
771        matched in multiline mode, the following line was shown as part of the
772        match. This seems wrong, so I have changed it.
774    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
775        the check for further matches in the same line (so they could be coloured)
776        to overrun the end of the current line. If another match was found, it was
777        incorrectly shown (and then shown again when found in the next line).
779    7.  If pcregrep was compiled under Windows, there was a reference to the
780        function pcregrep_exit() before it was defined. I am assuming this was
781        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
782        reported by a user. I've moved the definition above the reference.
785    Version 8.11 10-Dec-2010
786    ------------------------
788    1.  (*THEN) was not working properly if there were untried alternatives prior
789        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
790        backtracked to try for "b" instead of moving to the next alternative branch
791        at the same level (in this case, to look for "c"). The Perl documentation
792        is clear that when (*THEN) is backtracked onto, it goes to the "next
793        alternative in the innermost enclosing group".
795    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
796        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
797        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
798        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
799        (*THEN).
801    3.  If \s appeared in a character class, it removed the VT character from
802        the class, even if it had been included by some previous item, for example
803        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
804        of \s, but is part of the POSIX "space" class.)
806    4.  A partial match never returns an empty string (because you can always
807        match an empty string at the end of the subject); however the checking for
808        an empty string was starting at the "start of match" point. This has been
809        changed to the "earliest inspected character" point, because the returned
810        data for a partial match starts at this character. This means that, for
811        example, /(?<=abc)def/ gives a partial match for the subject "abc"
812        (previously it gave "no match").
814    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
815        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
816        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
817        has an implication that the given string is incomplete (because a partial
818        match is preferred over a full match). For this reason, these items now
819        give a partial match in this situation. [Aside: previously, the one case
820        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
821        match rather than a full match, which was wrong by the old rules, but is
822        now correct.]
824    6.  There was a bug in the handling of #-introduced comments, recognized when
825        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
826        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
827        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
828        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
829        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
830        places in pcre_compile().
832    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
833        comments when looking ahead for named forward references to subpatterns,
834        the only newline sequence it recognized was NL. It now handles newlines
835        according to the set newline convention.
837    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
838        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
839        cater for a lack of strerror(). These oversights have been fixed.
841    9.  Added --match-limit and --recursion-limit to pcregrep.
843    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
845    11. When the -o option was used, pcregrep was setting a return code of 1, even
846        when matches were found, and --line-buffered was not being honoured.
848    12. Added an optional parentheses number to the -o and --only-matching options
849        of pcregrep.
851    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
852        can match an empty string. The code to do it in pcretest and pcredemo
853        needed fixing:
855        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
856            only one byte after an empty string match just before CRLF (this case
857            just got forgotten; "any" and "anycrlf" were OK).
859        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
860            mode when an empty string match preceded an ASCII character followed by
861            a non-ASCII character. (The code for advancing by one character rather
862            than one byte was nonsense.)
864        (c) The pcredemo.c sample program did not have any code at all to handle
865            the cases when CRLF is a valid newline sequence.
867    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
868        as a starting offset was within the subject string. There is now a new
869        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
870        negative or greater than the length of the string. In order to test this,
871        pcretest is extended to allow the setting of negative starting offsets.
873    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
874        starting offset points to the beginning of a UTF-8 character was
875        unnecessarily clumsy. I tidied it up.
877    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
878        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
880    17. Nobody had reported that the --include_dir option, which was added in
881        release 7.7 should have been called --include-dir (hyphen, not underscore)
882        for compatibility with GNU grep. I have changed it to --include-dir, but
883        left --include_dir as an undocumented synonym, and the same for
884        --exclude-dir, though that is not available in GNU grep, at least as of
885        release 2.5.4.
887    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
888        characters from a string of bytes) have been redefined so as not to use
889        loops, in order to improve performance in some environments. At the same
890        time, I abstracted some of the common code into auxiliary macros to save
891        repetition (this should not affect the compiled code).
893    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
894        compile-time error is now given if \c is not followed by an ASCII
895        character, that is, a byte less than 128. (In EBCDIC mode, the code is
896        different, and any byte value is allowed.)
898    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
899        START_OPTIMIZE option, which is now allowed at compile time - but just
900        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
901        to pcregrep and other applications that have no direct access to PCRE
902        options. The new /Y option in pcretest sets this option when calling
903        pcre_compile().
905    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
906        back references. Groups containing recursive back references were forced to
907        be atomic by that change, but in the case of named groups, the amount of
908        memory required was incorrectly computed, leading to "Failed: internal
909        error: code overflow". This has been fixed.
911    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
912        pcretest.c, to avoid build problems in some Borland environments.
915    Version 8.10 25-Jun-2010
916    ------------------------
918    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
919        THEN.
921    2.  (*ACCEPT) was not working when inside an atomic group.
923    3.  Inside a character class, \B is treated as a literal by default, but
924        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
925        causes the error). The code is unchanged, but I tidied the documentation.
927    4.  Inside a character class, PCRE always treated \R and \X as literals,
928        whereas Perl faults them if its -w option is set. I have changed PCRE so
929        that it faults them when PCRE_EXTRA is set.
931    5.  Added support for \N, which always matches any character other than
932        newline. (It is the same as "." when PCRE_DOTALL is not set.)
934    6.  When compiling pcregrep with newer versions of gcc which may have
935        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
936        declared with attribute warn_unused_result" were given. Just casting the
937        result to (void) does not stop the warnings; a more elaborate fudge is
938        needed. I've used a macro to implement this.
940    7.  Minor change to pcretest.c to avoid a compiler warning.
942    8.  Added four artifical Unicode properties to help with an option to make
943        \s etc use properties (see next item). The new properties are: Xan
944        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
946    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
947        use Unicode properties. (*UCP) at the start of a pattern can be used to set
948        this option. Modified pcretest to add /W to test this facility. Added
949        REG_UCP to make it available via the POSIX interface.
951    10. Added --line-buffered to pcregrep.
953    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
954        studied, and the match started with a letter with a code point greater than
955        127 whose first byte was different to the first byte of the other case of
956        the letter, the other case of this starting letter was not recognized
957        (#976).
959    12. If a pattern that was studied started with a repeated Unicode property
960        test, for example, \p{Nd}+, there was the theoretical possibility of
961        setting up an incorrect bitmap of starting bytes, but fortunately it could
962        not have actually happened in practice until change 8 above was made (it
963        added property types that matched character-matching opcodes).
965    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
966        possible starting bytes for non-anchored patterns.
968    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
969        \R, and also a number of cases that involve Unicode properties, both
970        explicit and implicit when PCRE_UCP is set.
972    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
973        input, it could crash or give wrong results if characters with values
974        greater than 0xc0 were present in the subject string. (Detail: it assumed
975        UTF-8 input when processing these items.)
977    16. Added a lot of (int) casts to avoid compiler warnings in systems where
978        size_t is 64-bit (#991).
980    17. Added a check for running out of memory when PCRE is compiled with
981        --disable-stack-for-recursion (#990).
983    18. If the last data line in a file for pcretest does not have a newline on
984        the end, a newline was missing in the output.
986    19. The default pcre_chartables.c file recognizes only ASCII characters (values
987        less than 128) in its various bitmaps. However, there is a facility for
988        generating tables according to the current locale when PCRE is compiled. It
989        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
990        characters, are recognized by isspace() and therefore were getting set in
991        these tables, and indeed these tables seem to approximate to ISO 8859. This
992        caused a problem in UTF-8 mode when pcre_study() was used to create a list
993        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
994        which of course cannot start UTF-8 characters. I have changed the code so
995        that only real ASCII characters (less than 128) and the correct starting
996        bytes for UTF-8 encodings are set for characters greater than 127 when in
997        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
998        altogether.)
1000    20. Added the /T option to pcretest so as to be able to run tests with non-
1001        standard character tables, thus making it possible to include the tests
1002        used for 19 above in the standard set of tests.
1004    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1005        reference to a subpattern the other side of a comment that contains an
1006        opening parenthesis caused either an internal compiling error, or a
1007        reference to the wrong subpattern.
1010    Version 8.02 19-Mar-2010
1011  ------------------------  ------------------------
1013  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
1015    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1016        configured.
1018    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1019        original author of that file, following a query about its status.
1021    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1022        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1024    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1025        quantifier applied to a forward-referencing subroutine call, could compile
1026        incorrect code or give the error "internal error: previously-checked
1027        referenced subpattern not found".
1029    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1030        variables to point to external functions. For these systems, therefore,
1031        pcre_malloc etc. are now initialized to local functions that call the
1032        relevant global functions.
1034    7.  There were two entries missing in the vectors called coptable and poptable
1035        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1036        I've fixed the data, and added a kludgy way of testing at compile time that
1037        the lengths are correct (equal to the number of opcodes).
1039    8.  Following on from 7, I added a similar kludge to check the length of the
1040        eint vector in pcreposix.c.
1042    9.  Error texts for pcre_compile() are held as one long string to avoid too
1043        much relocation at load time. To find a text, the string is searched,
1044        counting zeros. There was no check for running off the end of the string,
1045        which could happen if a new error number was added without updating the
1046        string.
1048    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1050    11. \K was not working if it appeared in an atomic group or in a group that
1051        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1052        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1053        the assertion is positive, but not if it is negative.
1055    12. Change 11 fortuitously reduced the size of the stack frame used in the
1056        "match()" function of pcre_exec.c by one pointer. Forthcoming
1057        implementation of support for (*MARK) will need an extra pointer on the
1058        stack; I have reserved it now, so that the stack frame size does not
1059        decrease.
1061    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1062        item in branch that calls a recursion is a subroutine call - as in the
1063        second branch in the above example - was incorrectly given the compile-
1064        time error "recursive call could loop indefinitely" because pcre_compile()
1065        was not correctly checking the subroutine for matching a non-empty string.
1067    14. The checks for overrunning compiling workspace could trigger after an
1068        overrun had occurred. This is a "should never occur" error, but it can be
1069        triggered by pathological patterns such as hundreds of nested parentheses.
1070        The checks now trigger 100 bytes before the end of the workspace.
1072    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1075  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
1076  ------------------------  ------------------------

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