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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.33 xx-xxxx-201x
5    -------------------------
7    1.  Added 'U' to some constants that are compared to unsigned integers, to
8        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
9        variables that are added to signed variables, to ensure the result is
10        signed and can be negated.
12    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
13        CMake config files.
15    3.  Revise the creation of config.h.generic so that all boolean macros are
16        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
17        overriding via -D on the command line possible.
19    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
20        to unsigned int is reported to make a quite noticeable speed difference in
21        a specific Windows environment. Testing on Linux did also appear to show
22        some benefit (and it is clearly not harmful). Also fixed the definition of
23        Xop which should be unsigned.
25    5.  Related to (4), changing the definition of the intermediate variable cc
26        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
27        improvements.
29    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
30        unnecessary spaces.
32    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
33        and later.
35    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
37    9.  Optimizing fast_forward_start_bits in JIT.
39    10. Adding experimental support for callouts in JIT, and fixing some
40        issues revealed during this work. Namely:
42        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
44        (b) Minimum length was not checked before the matching is started.
46    11. The value of capture_last that is passed to callouts was incorrect in some
47        cases when there was a capture on one path that was subsequently abandoned
48        after a backtrack. Also, the capture_last value is now reset after a
49        recursion, since all captures are also reset in this case.
51    12. The interpreter no longer returns the "too many substrings" error in the
52        case when an overflowing capture is in a branch that is subsequently
53        abandoned after a backtrack.
55    13. In the pathological case when an offset vector of size 2 is used, pcretest
56        now prints out the matched string after a yield of 0 or 1.
58    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
59        Only supported by the JIT compiler at the moment.
61    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
63    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
64        offset of the starting point of the matching process, provided the offsets
65        vector is large enough.
67    17. The \A escape now records a lookbehind value of 1, though its execution
68        does not actually inspect the previous character. This is to ensure that,
69        in partial multi-segment matching, at least one character from the old
70        segment is retained when a new segment is processed. Otherwise, if there
71        are no lookbehinds in the pattern, \A might match incorrectly at the start
72        of a new segment.
74    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
76    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
77        gives some modest performance improvement in 8-bit mode.
79    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
80        be expressed in certain programming languages using Universal Character
81        Names.
83    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
84        which points out that "non characters" are not "characters that may not
85        appear in Unicode strings" but rather "characters that are reserved for
86        internal use and have only local meaning".
88    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
89        there was a conditional group that depended on an assertion, if the
90        assertion was false, the callout that immediately followed the alternation
91        in the condition was skipped when pcre_exec() was used for matching.
93    23. Allow an explicit callout to be inserted before an assertion that is the
94        condition for a conditional group, for compatibility with automatic
95        callouts, which always insert a callout at this point.
97    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
98        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
100    25. (*PRUNE) is now supported by the JIT compiler.
102    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
104    27. Fix the case where there are two or more SKIPs with arguments that may be
105        ignored.
107    28. Experimental support of (*SKIP) backtracking verb in the JIT compiler.
109    29. Experimental support of (*THEN) backtracking verb in the JIT compiler.
112    Version 8.32 30-November-2012
113    -----------------------------
115    1.  Improved JIT compiler optimizations for first character search and single
116        character iterators.
118    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
119        Patch by Daniel Richard G.
121    3.  Single character iterator optimizations in the JIT compiler.
123    4.  Improved JIT compiler optimizations for character ranges.
125    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
126        Reported by Giuseppe D'Angelo.
128    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
129        of a line, was being set incorrectly in cases where .* appeared inside
130        atomic brackets at the start of a pattern, or where there was a subsequent
131        *PRUNE or *SKIP.
133    7.  Improved instruction cache flush for POWER/PowerPC.
134        Patch by Daniel Richard G.
136    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
137        grep:
139        (a) There is now no limit to the number of patterns to be matched.
141        (b) An error is given if a pattern is too long.
143        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
144            are now supported.
146        (d) --exclude-from and --include-from (multiple use) have been added.
148        (e) Exclusions and inclusions now apply to all files and directories, not
149            just to those obtained from scanning a directory recursively.
151        (f) Multiple uses of -f and --file-list are now supported.
153        (g) In a Windows environment, the default for -d has been changed from
154            "read" (the GNU grep default) to "skip", because otherwise the presence
155            of a directory in the file list provokes an error.
157        (h) The documentation has been revised and clarified in places.
159    9.  Improve the matching speed of capturing brackets.
161    10. Changed the meaning of \X so that it now matches a Unicode extended
162        grapheme cluster.
164    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
165        out POSIX threads when JIT support is configured.
167    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
169    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
170        structure could go wrong in environments where size_t is not the same size
171        as int.
173    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
174        set.
176    15. The EBCDIC support had decayed; later updates to the code had included
177        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
178        general tidy up of EBCDIC-related issues, and the documentation was also
179        not quite right. There is now a test that can be run on ASCII systems to
180        check some of the EBCDIC-related things (but is it not a full test).
182    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
183        in a small tidy to the code.
185    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
187    18. If the --only-matching (-o) option in pcregrep is specified multiple
188        times, each one causes appropriate output. For example, -o1 -o2 outputs the
189        substrings matched by the 1st and 2nd capturing parentheses. A separating
190        string can be specified by --om-separator (default empty).
192    19. Improving the first n character searches.
194    20. Turn case lists for horizontal and vertical white space into macros so that
195        they are defined only once.
197    21. This set of changes together give more compatible Unicode case-folding
198        behaviour for characters that have more than one other case when UCP
199        support is available.
201        (a) The Unicode property table now has offsets into a new table of sets of
202            three or more characters that are case-equivalent. The MultiStage2.py
203            script that generates these tables (the pcre_ucd.c file) now scans
204            CaseFolding.txt instead of UnicodeData.txt for character case
205            information.
207        (b) The code for adding characters or ranges of characters to a character
208            class has been abstracted into a generalized function that also handles
209            case-independence. In UTF-mode with UCP support, this uses the new data
210            to handle characters with more than one other case.
212        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
213            whose other case is greater than 256 are now correctly matched
214            caselessly. Previously, the high codepoint matched the low one, but not
215            vice versa.
217        (d) The processing of \h, \H, \v, and \ in character classes now makes use
218            of the new class addition function, using character lists defined as
219            macros alongside the case definitions of 20 above.
221        (e) Caseless back references now work with characters that have more than
222            one other case.
224        (f) General caseless matching of characters with more than one other case
225            is supported.
227    22. Unicode character properties were updated from Unicode 6.2.0
229    23. Improved CMake support under Windows. Patch by Daniel Richard G.
231    24. Add support for 32-bit character strings, and UTF-32
233    25. Major JIT compiler update (code refactoring and bugfixing).
234        Experimental Sparc 32 support is added.
236    26. Applied a modified version of Daniel Richard G's patch to create
237        pcre.h.generic and config.h.generic by "make" instead of in the
238        PrepareRelease script.
240    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
241        pcre_compile.c when checking for a zero character.
243    28. Introducing a native interface for JIT. Through this interface, the compiled
244        machine code can be directly executed. The purpose of this interface is to
245        provide fast pattern matching, so several sanity checks are not performed.
246        However, feature tests are still performed. The new interface provides
247        1.4x speedup compared to the old one.
249    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
250        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
251        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
253    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
254        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
255        the "old" RFC 2279). Instead, it ended up passing a negative length to
256        pcre_exec().
258    31. Add support for GCC's visibility feature to hide internal functions.
260    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
261        "unknown -C option" after outputting 0 or 1.
263    33. There is now support for generating a code coverage report for the test
264        suite in environments where gcc is the compiler and lcov is installed. This
265        is mainly for the benefit of the developers.
267    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
268        unaddressable using valgrind annotations, allowing valgrind to detect
269        invalid memory accesses. This is mainly for the benefit of the developers.
271    25. (*UTF) can now be used to start a pattern in any of the three libraries.
273    26. Give configure error if --enable-cpp but no C++ compiler found.
276    Version 8.31 06-July-2012
277    -------------------------
279    1.  Fixing a wrong JIT test case and some compiler warnings.
281    2.  Removed a bashism from the RunTest script.
283    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
284        to unsigned type, result still unsigned" that was given by an MS compiler
285        on encountering the code "-sizeof(xxx)".
287    4.  Partial matching support is added to the JIT compiler.
289    5.  Fixed several bugs concerned with partial matching of items that consist
290        of more than one character:
292        (a) /^(..)\1/ did not partially match "aba" because checking references was
293            done on an "all or nothing" basis. This also applied to repeated
294            references.
296        (b) \R did not give a hard partial match if \r was found at the end of the
297            subject.
299        (c) \X did not give a hard partial match after matching one or more
300            characters at the end of the subject.
302        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
303            a partial match for the string "\r".
305        (e) When newline was set to CRLF, the metacharacter "." did not recognize
306            a partial match for a CR character at the end of the subject string.
308    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
309        running pcretest, the text "(JIT)" added to the output whenever JIT is
310        actually used to run the match.
312    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
313        or /S+[+] with a digit between 1 and 7.
315    8.  OP_NOT now supports any UTF character not just single-byte ones.
317    9.  (*MARK) control verb is now supported by the JIT compiler.
319    10. The command "./RunTest list" lists the available tests without actually
320        running any of them. (Because I keep forgetting what they all are.)
324    12. Applied a (slightly modified) user-supplied patch that improves performance
325        when the heap is used for recursion (compiled with --disable-stack-for-
326        recursion). Instead of malloc and free for each heap frame each time a
327        logical recursion happens, frames are retained on a chain and re-used where
328        possible. This sometimes gives as much as 30% improvement.
330    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
331        call.
333    14. As documented, (*COMMIT) is now confined to within a positive assertion.
335    15. It is now possible to link pcretest with libedit as an alternative to
336        libreadline.
338    16. (*COMMIT) control verb is now supported by the JIT compiler.
340    17. The Unicode data tables have been updated to Unicode 6.1.0.
342    18. Added --file-list option to pcregrep.
344    19. Added binary file support to pcregrep, including the -a, --binary-files,
345        -I, and --text options.
347    20. The madvise function is renamed for posix_madvise for QNX compatibility
348        reasons. Fixed by Giuseppe D'Angelo.
350    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
352    22. Changed the option for creating symbolic links for 16-bit man pages from
353        -s to -sf so that re-installing does not cause issues.
355    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
357    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
358        matches in certain environments (the workspace was not being correctly
359        retained). Also added to pcre_dfa_exec() a simple plausibility check on
360        some of the workspace data at the beginning of a restart.
362    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
363        was not doing so when it should - probably a typo introduced by SVN 528
364        (change 8.10/14).
366    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
367        \w+ when the character tables indicated that \x{c4} was a word character.
368        There were several related cases, all because the tests for doing a table
369        lookup were testing for characters less than 127 instead of 255.
371    27. If a pattern contains capturing parentheses that are not used in a match,
372        their slots in the ovector are set to -1. For those that are higher than
373        any matched groups, this happens at the end of processing. In the case when
374        there were back references that the ovector was too small to contain
375        (causing temporary malloc'd memory to be used during matching), and the
376        highest capturing number was not used, memory off the end of the ovector
377        was incorrectly being set to -1. (It was using the size of the temporary
378        memory instead of the true size.)
380    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
381        ovector size, it uses memory at the end of the block that it has got.
383    29. Check for an overlong MARK name and give an error at compile time. The
384        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
386    30. JIT compiler update.
388    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
389        Rill for the patch.
391    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
393    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
395    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
396        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
397        was enabled.
399    35. Improve JIT code generation for greedy plus quantifier.
401    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
402        1 to "aa" instead of to an empty string. The bug affected repeated groups
403        that could potentially match an empty string.
405    37. Optimizing single character iterators in JIT.
407    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
408        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
409        codepoints that are too big for the mode are faulted, and in a UTF mode,
410        disallowed codepoints are also faulted.
412    39. If PCRE was compiled with UTF support, in three places in the DFA
413        matcher there was code that should only have been obeyed in UTF mode, but
414        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
415        processing when bytes with values greater than 127 were present. In 16-bit
416        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
417        both cases the values are those that cannot be the first data item in a UTF
418        character. The three items that might have provoked this were recursions,
419        possessively repeated groups, and atomic groups.
421    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
422        and pcregrep, because some OS require shared objects to be explicitly
423        passed to ld, causing the link step to fail if they are not.
425    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
426        mode, patterns that started with \h* or \R* might be incorrectly matched.
429    Version 8.30 04-February-2012
430    -----------------------------
432    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
433        name is defined in ctype.h.
435    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
436        only in quite long subpatterns.
438    3.  Removed the function pcre_info(), which has been obsolete and deprecated
439        since it was replaced by pcre_fullinfo() in February 2000.
441    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
442        match a (*MARK), and the match failed at the start of the subject, a
443        reference to memory before the start of the subject could occur. This bug
444        was introduced by fix 17 of release 8.21.
446    5.  A reference to an unset group with zero minimum repetition was giving
447        totally wrong answers (in non-JavaScript-compatibility mode). For example,
448        /(another)?(\1?)test/ matched against "hello world test". This bug was
449        introduced in release 8.13.
451    6.  Add support for 16-bit character strings (a large amount of work involving
452        many changes and refactorings).
454    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
455        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
456        from a file.
458    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
459        rounding is not applied in this particular case).
461    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
462        if they appear, or are escaped, in patterns.
464    10. Get rid of a number of -Wunused-but-set-variable warnings.
466    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
467        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
468        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
469        also returns the mark "x". This bug applied to capturing parentheses,
470        non-capturing parentheses, and atomic parentheses. It also applied to some
471        assertions.
473    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
474        information out of configure.ac instead of relying on pcre.h.generic, which
475        is not stored in the repository.
477    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
478        -lreadline.
480    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
482    15. Applied Graycode's patch to put the top-level frame on the stack rather
483        than the heap when not using the stack for recursion. This gives a
484        performance improvement in many cases when recursion is not deep.
486    16. Experimental code added to "pcretest -C" to output the stack frame size.
489    Version 8.21 12-Dec-2011
490    ------------------------
492    1.  Updating the JIT compiler.
494    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
495        are added as well.
497    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
498        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
499        calling _pcre_jit_exec. Some extra comments are added.
501    4.  (*MARK) settings inside atomic groups that do not contain any capturing
502        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
503        was introduced by change 18 for 8.20.
505    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
506        ECMA-262 standard.
508    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
509        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
510        This bug was probably introduced by change 9 of 8.13.
512    7.  While fixing 6 above, I noticed that a number of other items were being
513        incorrectly rejected as "not fixed length". This arose partly because newer
514        opcodes had not been added to the fixed-length checking code. I have (a)
515        corrected the bug and added tests for these items, and (b) arranged for an
516        error to occur if an unknown opcode is encountered while checking for fixed
517        length instead of just assuming "not fixed length". The items that were
518        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
519        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
520        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
522    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
523        being incorrectly compiled and would have given unpredicatble results.
525    9.  A possessively repeated subpattern with minimum repeat count greater than
526        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
527        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
528        the first (A) could occur when it should not.
530    10. Add a cast and remove a redundant test from the code.
532    11. JIT should use pcre_malloc/pcre_free for allocation.
534    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
535        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
536        is anything other than /usr, -L is still shown).
538    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
540    14. Perl does not support \N without a following name in a [] class; PCRE now
541        also gives an error.
543    15. If a forward reference was repeated with an upper limit of around 2000,
544        it caused the error "internal error: overran compiling workspace". The
545        maximum number of forward references (including repeats) was limited by the
546        internal workspace, and dependent on the LINK_SIZE. The code has been
547        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
548        the default depends on LINK_SIZE. There is a new upper limit (for safety)
549        of around 200,000 forward references. While doing this, I also speeded up
550        the filling in of repeated forward references.
552    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
553        incorrectly expecting the subject to contain another "a" after the start.
555    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
556        in the match, the SKIP should be ignored. This was not happening; instead
557        the SKIP was being treated as NOMATCH. For patterns such as
558        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
559        tested.
561    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
562        now much more compatible with Perl, in particular in cases where the result
563        is a non-match for a non-anchored pattern. For example, if
564        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
565        "m", where previously it did not return a name. A side effect of this
566        change is that for partial matches, the last encountered mark name is
567        returned, as for non matches. A number of tests that were previously not
568        Perl-compatible have been moved into the Perl-compatible test files. The
569        refactoring has had the pleasing side effect of removing one argument from
570        the match() function, thus reducing its stack requirements.
572    19. If the /S+ option was used in pcretest to study a pattern using JIT,
573        subsequent uses of /S (without +) incorrectly behaved like /S+.
575    21. Retrieve executable code size support for the JIT compiler and fixing
576        some warnings.
578    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
579        not work when the shorter character appeared right at the end of the
580        subject string.
582    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
583        systems.
585    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
586        output it when the /M option is used in pcretest.
588    25. The CheckMan script was not being included in the distribution. Also, added
589        an explicit "perl" to run Perl scripts from the PrepareRelease script
590        because this is reportedly needed in Windows.
592    26. If study data was being save in a file and studying had not found a set of
593        "starts with" bytes for the pattern, the data written to the file (though
594        never used) was taken from uninitialized memory and so caused valgrind to
595        complain.
597    27. Updated RunTest.bat as provided by Sheri Pierce.
599    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
601    29. Computation of memory usage for the table of capturing group names was
602        giving an unnecessarily large value.
605    Version 8.20 21-Oct-2011
606    ------------------------
608    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
609        a POSIX class. After further experiments with Perl, which convinced me that
610        Perl has bugs and confusions, a closing square bracket is no longer allowed
611        in a POSIX name. This bug also affected patterns with classes that started
612        with full stops.
614    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
615        captured substring, but while checking the failing first alternative,
616        substring 1 is temporarily captured. If the output vector supplied to
617        pcre_exec() was not big enough for this capture, the yield of the function
618        was still zero ("insufficient space for captured substrings"). This cannot
619        be totally fixed without adding another stack variable, which seems a lot
620        of expense for a edge case. However, I have improved the situation in cases
621        such as /(a)(b)x|abc/ matched against "abc", where the return code
622        indicates that fewer than the maximum number of slots in the ovector have
623        been set.
625    3.  Related to (2) above: when there are more back references in a pattern than
626        slots in the output vector, pcre_exec() uses temporary memory during
627        matching, and copies in the captures as far as possible afterwards. It was
628        using the entire output vector, but this conflicts with the specification
629        that only 2/3 is used for passing back captured substrings. Now it uses
630        only the first 2/3, for compatibility. This is, of course, another edge
631        case.
633    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
634        main code base, and can be used by building with --enable-jit. When this is
635        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
636        runtime --no-jit option is given.
638    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
639        ovector, the return from the function was zero, implying that there were
640        other matches that did not fit. The correct "exactly full" value is now
641        returned.
643    6.  If a subpattern that was called recursively or as a subroutine contained
644        (*PRUNE) or any other control that caused it to give a non-standard return,
645        invalid errors such as "Error -26 (nested recursion at the same subject
646        position)" or even infinite loops could occur.
648    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
649        computing the minimum length on reaching *ACCEPT, and so ended up with the
650        wrong value of 1 rather than 0. Further investigation indicates that
651        computing a minimum subject length in the presence of *ACCEPT is difficult
652        (think back references, subroutine calls), and so I have changed the code
653        so that no minimum is registered for a pattern that contains *ACCEPT.
655    8.  If (*THEN) was present in the first (true) branch of a conditional group,
656        it was not handled as intended. [But see 16 below.]
658    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
659        Sheri Pierce.
661    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
662        the first byte in a match must be "a".
664    11. Change 17 for 8.13 increased the recursion depth for patterns like
665        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
666        pattern contains any instances of (*THEN). If it does not, the old
667        optimizations are restored. It would be nice to do this on a per-group
668        basis, but at the moment that is not feasible.
670    12. In some environments, the output of pcretest -C is CRLF terminated. This
671        broke RunTest's code that checks for the link size. A single white space
672        character after the value is now allowed for.
674    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
675        For "fr", it uses the Windows-specific input and output files.
677    14. If (*THEN) appeared in a group that was called recursively or as a
678        subroutine, it did not work as intended. [But see next item.]
680    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
681        pattern fragments (but not containing any | characters). If A and B are
682        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
683        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
684        D. In other words, Perl considers parentheses that do not contain any |
685        characters to be part of a surrounding alternative, whereas PCRE was
686        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
687        differently. PCRE now behaves in the same way as Perl, except in the case
688        of subroutine/recursion calls such as (?1) which have in any case always
689        been different (but PCRE had them first :-).
691    16. Related to 15 above: Perl does not treat the | in a conditional group as
692        creating alternatives. Such a group is treated in the same way as an
693        ordinary group without any | characters when processing (*THEN). PCRE has
694        been changed to match Perl's behaviour.
696    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
697        RunGrepTest script failed.
699    18. Change 22 for version 13 caused atomic groups to use more stack. This is
700        inevitable for groups that contain captures, but it can lead to a lot of
701        stack use in large patterns. The old behaviour has been restored for atomic
702        groups that do not contain any capturing parentheses.
704    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
705        suppress the check for a minimum subject length at run time. (If it was
706        given to pcre_exec() or pcre_dfa_exec() it did work.)
708    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
709        fail to work when decoding hex characters in data strings in EBCDIC
710        environments.
712    21. It appears that in at least one Mac OS environment, the isxdigit() function
713        is implemented as a macro that evaluates to its argument more than once,
714        contravening the C 90 Standard (I haven't checked a later standard). There
715        was an instance in pcretest which caused it to go wrong when processing
716        \x{...} escapes in subject strings. The has been rewritten to avoid using
717        things like p++ in the argument of isxdigit().
720    Version 8.13 16-Aug-2011
721    ------------------------
723    1.  The Unicode data tables have been updated to Unicode 6.0.0.
725    2.  Two minor typos in pcre_internal.h have been fixed.
727    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
728        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
729        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
731    4.  There were a number of related bugs in the code for matching backrefences
732        caselessly in UTF-8 mode when codes for the characters concerned were
733        different numbers of bytes. For example, U+023A and U+2C65 are an upper
734        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
735        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
736        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
737        2-byte code at the end of the subject (it thought there wasn't enough data
738        left).
740    5.  Comprehensive information about what went wrong is now returned by
741        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
742        as the output vector has at least 2 elements. The offset of the start of
743        the failing character and a reason code are placed in the vector.
745    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
746        now returned is for the first byte of the failing character, instead of the
747        last byte inspected. This is an incompatible change, but I hope it is small
748        enough not to be a problem. It makes the returned offset consistent with
749        pcre_exec() and pcre_dfa_exec().
751    7.  pcretest now gives a text phrase as well as the error number when
752        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
753        failure, the offset and reason code are output.
755    8.  When \R was used with a maximizing quantifier it failed to skip backwards
756        over a \r\n pair if the subsequent match failed. Instead, it just skipped
757        back over a single character (\n). This seems wrong (because it treated the
758        two characters as a single entity when going forwards), conflicts with the
759        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
760        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
761        has been changed.
763    9.  Some internal refactoring has changed the processing so that the handling
764        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
765        time (the PCRE_DOTALL option was changed this way some time ago: version
766        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
767        which was always a bit of a fudge. It also means that there is one less
768        argument for the match() function, which reduces its stack requirements
769        slightly. This change also fixes an incompatibility with Perl: the pattern
770        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
772    10. More internal refactoring has drastically reduced the number of recursive
773        calls to match() for possessively repeated groups such as (abc)++ when
774        using pcre_exec().
776    11. While implementing 10, a number of bugs in the handling of groups were
777        discovered and fixed:
779        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
780        (a|)*(?1) gave a compile-time internal error.
781        ((a|)+)+  did not notice that the outer group could match an empty string.
782        (^a|^)+   was not marked as anchored.
783        (.*a|.*)+ was not marked as matching at start or after a newline.
785    12. Yet more internal refactoring has removed another argument from the match()
786        function. Special calls to this function are now indicated by setting a
787        value in a variable in the "match data" data block.
789    13. Be more explicit in pcre_study() instead of relying on "default" for
790        opcodes that mean there is no starting character; this means that when new
791        ones are added and accidentally left out of pcre_study(), testing should
792        pick them up.
794    14. The -s option of pcretest has been documented for ages as being an old
795        synonym of -m (show memory usage). I have changed it to mean "force study
796        for every regex", that is, assume /S for every regex. This is similar to -i
797        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
798        using it. It makes it easier to run collections of tests with and without
799        study enabled, and thereby test pcre_study() more easily. All the standard
800        tests are now run with and without -s (but some patterns can be marked as
801        "never study" - see 20 below).
803    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
804        restoration of the capturing data to the outer values was not happening
805        correctly.
807    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
808        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
809        pattern had matched an empty string, and so incorrectly returned a no
810        match.
812    17. There was optimizing code for the last branch of non-capturing parentheses,
813        and also for the obeyed branch of a conditional subexpression, which used
814        tail recursion to cut down on stack usage. Unfortunately, now that there is
815        the possibility of (*THEN) occurring in these branches, tail recursion is
816        no longer possible because the return has to be checked for (*THEN). These
817        two optimizations have therefore been removed. [But see 8.20/11 above.]
819    18. If a pattern containing \R was studied, it was assumed that \R always
820        matched two bytes, thus causing the minimum subject length to be
821        incorrectly computed because \R can also match just one byte.
823    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
824        was incorrectly computed.
826    20. If /S is present twice on a test pattern in pcretest input, it now
827        *disables* studying, thereby overriding the use of -s on the command line
828        (see 14 above). This is necessary for one or two tests to keep the output
829        identical in both cases.
831    21. When (*ACCEPT) was used in an assertion that matched an empty string and
832        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
834    22. When an atomic group that contained a capturing parenthesis was
835        successfully matched, but the branch in which it appeared failed, the
836        capturing was not being forgotten if a higher numbered group was later
837        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
838        group 1 to "a", when in fact it should be unset. This applied to multi-
839        branched capturing and non-capturing groups, repeated or not, and also to
840        positive assertions (capturing in negative assertions does not happen
841        in PCRE) and also to nested atomic groups.
843    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
844        subject after a captured substring, to make it easier to tell which of a
845        number of identical substrings has been captured.
847    24. The way atomic groups are processed by pcre_exec() has been changed so that
848        if they are repeated, backtracking one repetition now resets captured
849        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
850        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
851        "aaa". Previously, it would have been "a". As part of this code
852        refactoring, the way recursive calls are handled has also been changed.
854    25. If an assertion condition captured any substrings, they were not passed
855        back unless some other capturing happened later. For example, if
856        (?(?=(a))a) was matched against "a", no capturing was returned.
858    26. When studying a pattern that contained subroutine calls or assertions,
859        the code for finding the minimum length of a possible match was handling
860        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
861        group 1 called group 2 while simultaneously a separate group 2 called group
862        1). A stack overflow occurred in this case. I have fixed this by limiting
863        the recursion depth to 10.
865    27. Updated RunTest.bat in the distribution to the version supplied by Tom
866        Fortmann. This supports explicit test numbers on the command line, and has
867        argument validation and error reporting.
869    28. An instance of \X with an unlimited repeat could fail if at any point the
870        first character it looked at was a mark character.
872    29. Some minor code refactoring concerning Unicode properties and scripts
873        should reduce the stack requirement of match() slightly.
875    30. Added the '=' option to pcretest to check the setting of unused capturing
876        slots at the end of the pattern, which are documented as being -1, but are
877        not included in the return count.
879    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
880        compiled something random. Now it gives a compile-time error (as does
881        Perl).
883    32. A *MARK encountered during the processing of a positive assertion is now
884        recorded and passed back (compatible with Perl).
886    33. If --only-matching or --colour was set on a pcregrep call whose pattern
887        had alternative anchored branches, the search for a second match in a line
888        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
889        matched the line "0102" twice. The same bug affected patterns that started
890        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
891        twice.
893    34. Previously, PCRE did not allow quantification of assertions. However, Perl
894        does, and because of capturing effects, quantifying parenthesized
895        assertions may at times be useful. Quantifiers are now allowed for
896        parenthesized assertions.
898    35. A minor code tidy in pcre_compile() when checking options for \R usage.
900    36. \g was being checked for fancy things in a character class, when it should
901        just be a literal "g".
903    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
904        appearance of a nested POSIX class supersedes an apparent external class.
905        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
906        unescaped square brackets may also appear as part of class names. For
907        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
908        more like Perl. (But see 8.20/1 above.)
910    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
911        was because it thought it was \N{name}, which is not supported).
913    39. Add minix to OS list not supporting the -S option in pcretest.
915    40. PCRE tries to detect cases of infinite recursion at compile time, but it
916        cannot analyze patterns in sufficient detail to catch mutual recursions
917        such as ((?1))((?2)). There is now a runtime test that gives an error if a
918        subgroup is called recursively as a subpattern for a second time at the
919        same position in the subject string. In previous releases this might have
920        been caught by the recursion limit, or it might have run out of stack.
922    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
923        happen only once. PCRE was, however incorrectly giving a compile time error
924        "recursive call could loop indefinitely" because it cannot analyze the
925        pattern in sufficient detail. The compile time test no longer happens when
926        PCRE is compiling a conditional subpattern, but actual runaway loops are
927        now caught at runtime (see 40 above).
929    42. It seems that Perl allows any characters other than a closing parenthesis
930        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
931        has been changed to be the same.
933    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
934        as not to get warnings when autogen.sh is called. Also changed
935        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
937    44. To help people who use pcregrep to scan files containing exceedingly long
938        lines, the following changes have been made:
940        (a) The default value of the buffer size parameter has been increased from
941            8K to 20K. (The actual buffer used is three times this size.)
943        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
944            PCRE is built.
946        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
947            to be set at run time.
949        (d) Numerical values in pcregrep options can be followed by K or M, for
950            example --buffer-size=50K.
952        (e) If a line being scanned overflows pcregrep's buffer, an error is now
953            given and the return code is set to 2.
955    45. Add a pointer to the latest mark to the callout data block.
957    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
958        partial match of an empty string instead of no match. This was specific to
959        the use of ".".
961    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
962        complete match instead of a partial match. This bug was dependent on both
963        the PCRE_UTF8 and PCRE_DOTALL options being set.
965    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
966        starting byte set, because \b was not being ignored.
969    Version 8.12 15-Jan-2011
970    ------------------------
972    1.  Fixed some typos in the markup of the man pages, and wrote a script that
973        checks for such things as part of the documentation building process.
975    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
976        --match-limit and --recursion-limit options (added for 8.11). In
977        particular, this made one of the standard tests fail. (The integer value
978        went into the wrong half of a long int.)
980    3.  If the --colour option was given to pcregrep with -v (invert match), it
981        did strange things, either producing crazy output, or crashing. It should,
982        of course, ignore a request for colour when reporting lines that do not
983        match.
985    4.  Another pcregrep bug caused similar problems if --colour was specified with
986        -M (multiline) and the pattern match finished with a line ending.
988    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
989        matched in multiline mode, the following line was shown as part of the
990        match. This seems wrong, so I have changed it.
992    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
993        the check for further matches in the same line (so they could be coloured)
994        to overrun the end of the current line. If another match was found, it was
995        incorrectly shown (and then shown again when found in the next line).
997    7.  If pcregrep was compiled under Windows, there was a reference to the
998        function pcregrep_exit() before it was defined. I am assuming this was
999        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1000        reported by a user. I've moved the definition above the reference.
1003    Version 8.11 10-Dec-2010
1004    ------------------------
1006    1.  (*THEN) was not working properly if there were untried alternatives prior
1007        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1008        backtracked to try for "b" instead of moving to the next alternative branch
1009        at the same level (in this case, to look for "c"). The Perl documentation
1010        is clear that when (*THEN) is backtracked onto, it goes to the "next
1011        alternative in the innermost enclosing group".
1013    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1014        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1015        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1016        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1017        (*THEN).
1019    3.  If \s appeared in a character class, it removed the VT character from
1020        the class, even if it had been included by some previous item, for example
1021        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1022        of \s, but is part of the POSIX "space" class.)
1024    4.  A partial match never returns an empty string (because you can always
1025        match an empty string at the end of the subject); however the checking for
1026        an empty string was starting at the "start of match" point. This has been
1027        changed to the "earliest inspected character" point, because the returned
1028        data for a partial match starts at this character. This means that, for
1029        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1030        (previously it gave "no match").
1032    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1033        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1034        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1035        has an implication that the given string is incomplete (because a partial
1036        match is preferred over a full match). For this reason, these items now
1037        give a partial match in this situation. [Aside: previously, the one case
1038        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1039        match rather than a full match, which was wrong by the old rules, but is
1040        now correct.]
1042    6.  There was a bug in the handling of #-introduced comments, recognized when
1043        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1044        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1045        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1046        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1047        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1048        places in pcre_compile().
1050    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1051        comments when looking ahead for named forward references to subpatterns,
1052        the only newline sequence it recognized was NL. It now handles newlines
1053        according to the set newline convention.
1055    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1056        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1057        cater for a lack of strerror(). These oversights have been fixed.
1059    9.  Added --match-limit and --recursion-limit to pcregrep.
1061    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1063    11. When the -o option was used, pcregrep was setting a return code of 1, even
1064        when matches were found, and --line-buffered was not being honoured.
1066    12. Added an optional parentheses number to the -o and --only-matching options
1067        of pcregrep.
1069    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1070        can match an empty string. The code to do it in pcretest and pcredemo
1071        needed fixing:
1073        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1074            only one byte after an empty string match just before CRLF (this case
1075            just got forgotten; "any" and "anycrlf" were OK).
1077        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1078            mode when an empty string match preceded an ASCII character followed by
1079            a non-ASCII character. (The code for advancing by one character rather
1080            than one byte was nonsense.)
1082        (c) The pcredemo.c sample program did not have any code at all to handle
1083            the cases when CRLF is a valid newline sequence.
1085    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1086        as a starting offset was within the subject string. There is now a new
1087        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1088        negative or greater than the length of the string. In order to test this,
1089        pcretest is extended to allow the setting of negative starting offsets.
1091    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1092        starting offset points to the beginning of a UTF-8 character was
1093        unnecessarily clumsy. I tidied it up.
1095    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1096        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1098    17. Nobody had reported that the --include_dir option, which was added in
1099        release 7.7 should have been called --include-dir (hyphen, not underscore)
1100        for compatibility with GNU grep. I have changed it to --include-dir, but
1101        left --include_dir as an undocumented synonym, and the same for
1102        --exclude-dir, though that is not available in GNU grep, at least as of
1103        release 2.5.4.
1105    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1106        characters from a string of bytes) have been redefined so as not to use
1107        loops, in order to improve performance in some environments. At the same
1108        time, I abstracted some of the common code into auxiliary macros to save
1109        repetition (this should not affect the compiled code).
1111    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1112        compile-time error is now given if \c is not followed by an ASCII
1113        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1114        different, and any byte value is allowed.)
1116    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1117        START_OPTIMIZE option, which is now allowed at compile time - but just
1118        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1119        to pcregrep and other applications that have no direct access to PCRE
1120        options. The new /Y option in pcretest sets this option when calling
1121        pcre_compile().
1123    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1124        back references. Groups containing recursive back references were forced to
1125        be atomic by that change, but in the case of named groups, the amount of
1126        memory required was incorrectly computed, leading to "Failed: internal
1127        error: code overflow". This has been fixed.
1129    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1130        pcretest.c, to avoid build problems in some Borland environments.
1133    Version 8.10 25-Jun-2010
1134    ------------------------
1136    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1137        THEN.
1139    2.  (*ACCEPT) was not working when inside an atomic group.
1141    3.  Inside a character class, \B is treated as a literal by default, but
1142        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1143        causes the error). The code is unchanged, but I tidied the documentation.
1145    4.  Inside a character class, PCRE always treated \R and \X as literals,
1146        whereas Perl faults them if its -w option is set. I have changed PCRE so
1147        that it faults them when PCRE_EXTRA is set.
1149    5.  Added support for \N, which always matches any character other than
1150        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1152    6.  When compiling pcregrep with newer versions of gcc which may have
1153        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1154        declared with attribute warn_unused_result" were given. Just casting the
1155        result to (void) does not stop the warnings; a more elaborate fudge is
1156        needed. I've used a macro to implement this.
1158    7.  Minor change to pcretest.c to avoid a compiler warning.
1160    8.  Added four artifical Unicode properties to help with an option to make
1161        \s etc use properties (see next item). The new properties are: Xan
1162        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1164    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1165        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1166        this option. Modified pcretest to add /W to test this facility. Added
1167        REG_UCP to make it available via the POSIX interface.
1169    10. Added --line-buffered to pcregrep.
1171    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1172        studied, and the match started with a letter with a code point greater than
1173        127 whose first byte was different to the first byte of the other case of
1174        the letter, the other case of this starting letter was not recognized
1175        (#976).
1177    12. If a pattern that was studied started with a repeated Unicode property
1178        test, for example, \p{Nd}+, there was the theoretical possibility of
1179        setting up an incorrect bitmap of starting bytes, but fortunately it could
1180        not have actually happened in practice until change 8 above was made (it
1181        added property types that matched character-matching opcodes).
1183    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1184        possible starting bytes for non-anchored patterns.
1186    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1187        \R, and also a number of cases that involve Unicode properties, both
1188        explicit and implicit when PCRE_UCP is set.
1190    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1191        input, it could crash or give wrong results if characters with values
1192        greater than 0xc0 were present in the subject string. (Detail: it assumed
1193        UTF-8 input when processing these items.)
1195    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1196        size_t is 64-bit (#991).
1198    17. Added a check for running out of memory when PCRE is compiled with
1199        --disable-stack-for-recursion (#990).
1201    18. If the last data line in a file for pcretest does not have a newline on
1202        the end, a newline was missing in the output.
1204    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1205        less than 128) in its various bitmaps. However, there is a facility for
1206        generating tables according to the current locale when PCRE is compiled. It
1207        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1208        characters, are recognized by isspace() and therefore were getting set in
1209        these tables, and indeed these tables seem to approximate to ISO 8859. This
1210        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1211        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1212        which of course cannot start UTF-8 characters. I have changed the code so
1213        that only real ASCII characters (less than 128) and the correct starting
1214        bytes for UTF-8 encodings are set for characters greater than 127 when in
1215        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1216        altogether.)
1218    20. Added the /T option to pcretest so as to be able to run tests with non-
1219        standard character tables, thus making it possible to include the tests
1220        used for 19 above in the standard set of tests.
1222    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1223        reference to a subpattern the other side of a comment that contains an
1224        opening parenthesis caused either an internal compiling error, or a
1225        reference to the wrong subpattern.
1228    Version 8.02 19-Mar-2010
1229    ------------------------
1231    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1233    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1234        configured.
1236    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1237        original author of that file, following a query about its status.
1239    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1240        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1242    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1243        quantifier applied to a forward-referencing subroutine call, could compile
1244        incorrect code or give the error "internal error: previously-checked
1245        referenced subpattern not found".
1247    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1248        variables to point to external functions. For these systems, therefore,
1249        pcre_malloc etc. are now initialized to local functions that call the
1250        relevant global functions.
1252    7.  There were two entries missing in the vectors called coptable and poptable
1253        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1254        I've fixed the data, and added a kludgy way of testing at compile time that
1255        the lengths are correct (equal to the number of opcodes).
1257    8.  Following on from 7, I added a similar kludge to check the length of the
1258        eint vector in pcreposix.c.
1260    9.  Error texts for pcre_compile() are held as one long string to avoid too
1261        much relocation at load time. To find a text, the string is searched,
1262        counting zeros. There was no check for running off the end of the string,
1263        which could happen if a new error number was added without updating the
1264        string.
1266    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1268    11. \K was not working if it appeared in an atomic group or in a group that
1269        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1270        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1271        the assertion is positive, but not if it is negative.
1273    12. Change 11 fortuitously reduced the size of the stack frame used in the
1274        "match()" function of pcre_exec.c by one pointer. Forthcoming
1275        implementation of support for (*MARK) will need an extra pointer on the
1276        stack; I have reserved it now, so that the stack frame size does not
1277        decrease.
1279    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1280        item in branch that calls a recursion is a subroutine call - as in the
1281        second branch in the above example - was incorrectly given the compile-
1282        time error "recursive call could loop indefinitely" because pcre_compile()
1283        was not correctly checking the subroutine for matching a non-empty string.
1285    14. The checks for overrunning compiling workspace could trigger after an
1286        overrun had occurred. This is a "should never occur" error, but it can be
1287        triggered by pathological patterns such as hundreds of nested parentheses.
1288        The checks now trigger 100 bytes before the end of the workspace.
1290    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1293    Version 8.01 19-Jan-2010
1294    ------------------------
1296    1.  If a pattern contained a conditional subpattern with only one branch (in
1297        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1298        computed the wrong minimum data length (which is of course zero for such
1299        subpatterns). This could cause incorrect "no match" results.
1301    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1302        the pattern is reset in the first branch, pcre_compile() failed with
1303        "internal error: code overflow at offset...". This happened only when
1304        the reset was to the original external option setting. (An optimization
1305        abstracts leading options settings into an external setting, which was the
1306        cause of this.)
1308    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1309        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1310        assertion pattern did not match (meaning that the assertion was true), it
1311        was incorrectly treated as false if the SKIP had been reached during the
1312        matching. This also applied to assertions used as conditions.
1314    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1315        assertion subpattern, including such a pattern used as a condition,
1316        unpredictable results occurred, instead of the error return
1319    5.  The C++ GlobalReplace function was not working like Perl for the special
1320        situation when an empty string is matched. It now does the fancy magic
1321        stuff that is necessary.
1323    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1324        removed. (These were left over from very, very early versions of PCRE.)
1326    7.  Some cosmetic changes to the code to make life easier when compiling it
1327        as part of something else:
1329        (a) Change DEBUG to PCRE_DEBUG.
1331        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1332            called "current" as "current_branch", to prevent a collision with the
1333            Linux macro when compiled as a kernel module.
1335        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1336            prevent a collision with the Linux macro when compiled as a kernel
1337            module.
1339    8.  In pcre_compile() there are some checks for integer overflows that used to
1340        cast potentially large values to (double). This has been changed to that
1341        when building, a check for int64_t is made, and if it is found, it is used
1342        instead, thus avoiding the use of floating point arithmetic. (There is no
1343        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1344        double.
1346    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1347        2005 (difference between two addresses compared to an unsigned value).
1349    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1350        custom one, because of the following reported problem in Windows:
1352          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1353              under Win32.
1354          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1355              therefore missing the function definition.
1356          - The compiler thus generates a "C" signature for the test function.
1357          - The linker fails to find the "C" function.
1358          - PCRE fails to configure if asked to do so against libbz2.
1360    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1361        messages were output:
1363          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1364          rerunning libtoolize, to keep the correct libtool macros in-tree.
1365          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1367        I have done both of these things.
1369    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1370        most of the time, it *can* run out if it is given a pattern that contains a
1371        runaway infinite recursion. I updated the discussion in the pcrestack man
1372        page.
1374    13. Now that we have gone to the x.xx style of version numbers, the minor
1375        version may start with zero. Using 08 or 09 is a bad idea because users
1376        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1377        interpreted as invalid octal numbers. I've updated the previous comment in
1378        configure.ac, and also added a check that gives an error if 08 or 09 are
1379        used.
1381    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1382        causing partial matching to fail when the end of the subject matched \W
1383        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1385    15. There were some discrepancies between the declarations in pcre_internal.h
1386        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1387        their definitions. The declarations used "const uschar *" and the
1388        definitions used USPTR. Even though USPTR is normally defined as "const
1389        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1390        reported that: "This difference in casting confuses some C++ compilers, for
1391        example, SunCC recognizes above declarations as different functions and
1392        generates broken code for hbpcre." I have changed the declarations to use
1393        USPTR.
1395    16. GNU libtool is named differently on some systems. The autogen.sh script now
1396        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1397        (FreeBSD).
1399    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1400        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1401        comment: "Figure out how to create a longlong from a string: strtoll and
1402        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1403        instance, but it only takes 2 args instead of 3!"
1405    18. A subtle bug concerned with back references has been fixed by a change of
1406        specification, with a corresponding code fix. A pattern such as
1407        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1408        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1409        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1410        same bug. Such groups have to be quantified to be useful, or contained
1411        inside another quantified group. (If there's no repetition, the reference
1412        can never match.) The problem arises because, having left the group and
1413        moved on to the rest of the pattern, a later failure that backtracks into
1414        the group uses the captured value from the final iteration of the group
1415        rather than the correct earlier one. I have fixed this in PCRE by forcing
1416        any group that contains a reference to itself to be an atomic group; that
1417        is, there cannot be any backtracking into it once it has completed. This is
1418        similar to recursive and subroutine calls.
1421    Version 8.00 19-Oct-09
1422    ----------------------
1424    1.  The table for translating pcre_compile() error codes into POSIX error codes
1425        was out-of-date, and there was no check on the pcre_compile() error code
1426        being within the table. This could lead to an OK return being given in
1427        error.
1429    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1430        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1431        in a Windows environment.
1433    3.  The pcregrep --count option prints the count for each file even when it is
1434        zero, as does GNU grep. However, pcregrep was also printing all files when
1435        --files-with-matches was added. Now, when both options are given, it prints
1436        counts only for those files that have at least one match. (GNU grep just
1437        prints the file name in this circumstance, but including the count seems
1438        more useful - otherwise, why use --count?) Also ensured that the
1439        combination -clh just lists non-zero counts, with no names.
1441    4.  The long form of the pcregrep -F option was incorrectly implemented as
1442        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1443        but it seems right to fix it, and I didn't think it was worth preserving
1444        the old behaviour.
1446    5.  The command line items --regex=pattern and --regexp=pattern were not
1447        recognized by pcregrep, which required --regex pattern or --regexp pattern
1448        (with a space rather than an '='). The man page documented the '=' forms,
1449        which are compatible with GNU grep; these now work.
1451    6.  No libpcreposix.pc file was created for pkg-config; there was just
1452        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1454    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1455        when UCP support is not needed, by modifying the Python script that
1456        generates it from Unicode data files. This should not matter if the module
1457        is correctly used as a library, but I received one complaint about 50K of
1458        unwanted data. My guess is that the person linked everything into his
1459        program rather than using a library. Anyway, it does no harm.
1461    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1462        was a minimum greater than 1 for a wide character in a possessive
1463        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1464        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1465        character. Chaos in the form of incorrect output or a compiling loop could
1466        result.
1468    9.  The restrictions on what a pattern can contain when partial matching is
1469        requested for pcre_exec() have been removed. All patterns can now be
1470        partially matched by this function. In addition, if there are at least two
1471        slots in the offset vector, the offset of the earliest inspected character
1472        for the match and the offset of the end of the subject are set in them when
1473        PCRE_ERROR_PARTIAL is returned.
1475    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1476        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1477        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1478        and may be more useful for multi-segment matching.
1480    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1481        used to be given if ever the end of the subject was reached; now it is
1482        given only if matching could not proceed because another character was
1483        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1484        string "Z", which now yields "no match" instead of "partial match". In the
1485        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1486        final character ended with (*FAIL).
1488    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1489        if the pattern had a "must contain" character that was already found in the
1490        earlier partial match, unless partial matching was again requested. For
1491        example, with the pattern /dog.(body)?/, the "must contain" character is
1492        "g". If the first part-match was for the string "dog", restarting with
1493        "sbody" failed. This bug has been fixed.
1495    13. The string returned by pcre_dfa_exec() after a partial match has been
1496        changed so that it starts at the first inspected character rather than the
1497        first character of the match. This makes a difference only if the pattern
1498        starts with a lookbehind assertion or \b or \B (\K is not supported by
1499        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1500        matching functions compatible, and I think it's the right thing to do.
1502    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1503        so that the demonstration program is easily available in environments where
1504        PCRE has not been installed from source.
1506    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1507        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1508        library.
1510    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1511        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1512        is not the first non-POSIX option to be added. Clearly some people find
1513        these options useful.
1515    17. If a caller to the POSIX matching function regexec() passes a non-zero
1516        value for nmatch with a NULL value for pmatch, the value of
1517        nmatch is forced to zero.
1519    18. RunGrepTest did not have a test for the availability of the -u option of
1520        the diff command, as RunTest does. It now checks in the same way as
1521        RunTest, and also checks for the -b option.
1523    19. If an odd number of negated classes containing just a single character
1524        interposed, within parentheses, between a forward reference to a named
1525        subpattern and the definition of the subpattern, compilation crashed with
1526        an internal error, complaining that it could not find the referenced
1527        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1528        [The bug was that it was starting one character too far in when skipping
1529        over the character class, thus treating the ] as data rather than
1530        terminating the class. This meant it could skip too much.]
1532    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1533        /g option in pcretest when the pattern contains \K, which makes it possible
1534        to have an empty string match not at the start, even when the pattern is
1535        anchored. Updated pcretest and pcredemo to use this option.
1537    21. If the maximum number of capturing subpatterns in a recursion was greater
1538        than the maximum at the outer level, the higher number was returned, but
1539        with unset values at the outer level. The correct (outer level) value is
1540        now given.
1542    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1543        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1544        make it do so. The string so far is captured, making this feature
1545        compatible with Perl.
1547    23. The tests have been re-organized, adding tests 11 and 12, to make it
1548        possible to check the Perl 5.10 features against Perl 5.10.
1550    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1551        pattern matches a fixed length string. PCRE did not allow this; now it
1552        does. Neither allows recursion.
1554    25. I finally figured out how to implement a request to provide the minimum
1555        length of subject string that was needed in order to match a given pattern.
1556        (It was back references and recursion that I had previously got hung up
1557        on.) This code has now been added to pcre_study(); it finds a lower bound
1558        to the length of subject needed. It is not necessarily the greatest lower
1559        bound, but using it to avoid searching strings that are too short does give
1560        some useful speed-ups. The value is available to calling programs via
1561        pcre_fullinfo().
1563    26. While implementing 25, I discovered to my embarrassment that pcretest had
1564        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1565        study optimizations had never been tested with that matching function.
1566        Oops. What is worse, even when it was passed study data, there was a bug in
1567        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1568        were also very few tests of studied patterns with pcre_dfa_exec().
1570    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1571        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1572        on the other side of the coin, they are no longer allowed to have different
1573        names, because these cannot be distinguished in PCRE, and this has caused
1574        confusion. (This is a difference from Perl.)
1576    28. When duplicate subpattern names are present (necessarily with different
1577        numbers, as required by 27 above), and a test is made by name in a
1578        conditional pattern, either for a subpattern having been matched, or for
1579        recursion in such a pattern, all the associated numbered subpatterns are
1580        tested, and the overall condition is true if the condition is true for any
1581        one of them. This is the way Perl works, and is also more like the way
1582        testing by number works.
1585    Version 7.9 11-Apr-09
1586    ---------------------
1588    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1589        (pcretest), all targets were linked against these libraries. This included
1590        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1591        libraries. This caused unwanted dependencies to be created. This problem
1592        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1593        pcretest is linked with readline.
1595    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1596        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1597        moved outside it again, because FALSE and TRUE are already defined in AIX,
1598        but BOOL is not.
1600    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1601        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1603    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1604        hyphens) following file names and line numbers when outputting matching
1605        lines. This is not true; no spaces are inserted. I have also clarified the
1606        wording for the --colour (or --color) option.
1608    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1609        was not coloured; this is different to GNU grep, so I have changed it to be
1610        the same.
1612    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1613        each matching line was coloured. Now it goes on to look for further matches
1614        of any of the test patterns, which is the same behaviour as GNU grep.
1616    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1617        doesn't make sense to accept an empty string match in pcregrep, so I have
1618        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1619        seems to be how GNU grep behaves.
1621    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1622        start or after a newline", because the conditional assertion was not being
1623        correctly handled. The rule now is that both the assertion and what follows
1624        in the first alternative must satisfy the test.
1626    9.  If auto-callout was enabled in a pattern with a conditional group whose
1627        condition was an assertion, PCRE could crash during matching, both with
1628        pcre_exec() and pcre_dfa_exec().
1630    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1631        used for matching.
1633    11. Unicode property support in character classes was not working for
1634        characters (bytes) greater than 127 when not in UTF-8 mode.
1636    12. Added the -M command line option to pcretest.
1638    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1640    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1642    16. Added comments and documentation about mis-use of no_arg in the C++
1643        wrapper.
1645    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1646        from Martin Jerabek that uses macro names for all relevant character and
1647        string constants.
1649    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1650        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1651        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1652        these, but not everybody uses configure.
1654    19. A conditional group that had only one branch was not being correctly
1655        recognized as an item that could match an empty string. This meant that an
1656        enclosing group might also not be so recognized, causing infinite looping
1657        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1658        with the subject "ab", where knowledge that the repeated group can match
1659        nothing is needed in order to break the loop.
1661    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1662        exec(), but without supplying a callout function, matching went wrong.
1664    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1665        leak if the size of the offset vector was greater than 30. When the vector
1666        is smaller, the saved offsets during recursion go onto a local stack
1667        vector, but for larger vectors malloc() is used. It was failing to free
1668        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1669        error, in fact).
1671    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1672        heapframe that is used only when UTF-8 support is enabled. This caused no
1673        problem, but was untidy.
1675    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1676        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1677        included within another project.
1679    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1680        slightly modified by me:
1682          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1683              not building pcregrep.
1685          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1686              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1688    25. Forward references, both numeric and by name, in patterns that made use of
1689        duplicate group numbers, could behave incorrectly or give incorrect errors,
1690        because when scanning forward to find the reference group, PCRE was not
1691        taking into account the duplicate group numbers. A pattern such as
1692        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1694    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1695        the feature of a custom pointer more persuasive (as requested by a user).
1697    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1698        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1699        pre-defined.
1701    28. Added support for (*UTF8) at the start of a pattern.
1703    29. Arrange for flags added by the "release type" setting in CMake to be shown
1704        in the configuration summary.
1707    Version 7.8 05-Sep-08
1708    ---------------------
1710    1.  Replaced UCP searching code with optimized version as implemented for Ad
1711        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1712        stage table and inline lookup instead of a function, giving speed ups of 2
1713        to 5 times on some simple patterns that I tested. Permission was given to
1714        distribute the MultiStage2.py script that generates the tables (it's not in
1715        the tarball, but is in the Subversion repository).
1717    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1718        scripts.
1720    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1721        a group with a zero qualifier. The result of the study could be incorrect,
1722        or the function might crash, depending on the pattern.
1724    4.  Caseless matching was not working for non-ASCII characters in back
1725        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1726        It now works when Unicode Property Support is available.
1728    5.  In pcretest, an escape such as \x{de} in the data was always generating
1729        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1730        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1731        truncation.
1733    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1735    7.  Added two (int) casts to pcregrep when printing the difference of two
1736        pointers, in case they are 64-bit values.
1738    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1739        test 2 if it fails.
1741    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1742        and a #define of that name to empty if it is not externally set. This is to
1743        allow users of MSVC to set it if necessary.
1745    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1746        the convenience functions in the pcre_get.c source file.
1748    11. An option change at the start of a pattern that had top-level alternatives
1749        could cause overwriting and/or a crash. This command provoked a crash in
1750        some environments:
1752          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1754        This potential security problem was recorded as CVE-2008-2371.
1756    12. For a pattern where the match had to start at the beginning or immediately
1757        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1758        pcre_dfa_exec() could read past the end of the passed subject if there was
1759        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1760        pcretest so that it places the subject at the end of its malloc-ed buffer.
1762    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1763        exec() might read past the end of the data buffer in UTF-8 mode.
1765    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1766        the data contained the byte 0x85 as part of a UTF-8 character within its
1767        first line. This applied both to normal and DFA matching.
1769    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1770        /^[^d]*?$/8 failed to match "abc".
1772    16. Added a missing copyright notice to pcrecpp_internal.h.
1774    17. Make it more clear in the documentation that values returned from
1775        pcre_exec() in ovector are byte offsets, not character counts.
1777    18. Tidied a few places to stop certain compilers from issuing warnings.
1779    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1780        supplied by Stefan Weber. I made a further small update for 7.8 because
1781        there is a change of source arrangements: the pcre_searchfuncs.c module is
1782        replaced by pcre_ucd.c.
1785    Version 7.7 07-May-08
1786    ---------------------
1788    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1789        a string to a long long, pretend we don't even have a long long." This is
1790        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1792    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1793        pre-7.6 versions, which defined a global no_arg variable instead of putting
1794        it in the RE class. (See also #8 below.)
1796    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1797        Lopes.
1799    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1801        (1) The include/exclude patterns were being applied to the whole pathnames
1802            of files, instead of just to the final components.
1804        (2) If there was more than one level of directory, the subdirectories were
1805            skipped unless they satisfied the include/exclude conditions. This is
1806            inconsistent with GNU grep (and could even be seen as contrary to the
1807            pcregrep specification - which I improved to make it absolutely clear).
1808            The action now is always to scan all levels of directory, and just
1809            apply the include/exclude patterns to regular files.
1811    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1812        --exclude_dir in the tests to avoid scanning .svn directories.
1814    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1815        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1816        doesn't support NULs in patterns.
1818    7.  Added some missing "const"s to declarations of static tables in
1819        pcre_compile.c and pcre_dfa_exec.c.
1821    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1822        caused by fix #2  above. (Subsequently also a second patch to fix the
1823        first patch. And a third patch - this was a messy problem.)
1825    9.  Applied Craig's patch to remove the use of push_back().
1827    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1828        matching function regexec().
1830    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1831        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1832        references. PCRE supports relative numbers with this syntax (I don't think
1833        Oniguruma does).
1835    12. Previously, a group with a zero repeat such as (...){0} was completely
1836        omitted from the compiled regex. However, this means that if the group
1837        was called as a subroutine from elsewhere in the pattern, things went wrong
1838        (an internal error was given). Such groups are now left in the compiled
1839        pattern, with a new opcode that causes them to be skipped at execution
1840        time.
1842    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1843        to the way PCRE behaves:
1845        (a) A lone ] character is dis-allowed (Perl treats it as data).
1847        (b) A back reference to an unmatched subpattern matches an empty string
1848            (Perl fails the current match path).
1850        (c) A data ] in a character class must be notated as \] because if the
1851            first data character in a class is ], it defines an empty class. (In
1852            Perl it is not possible to have an empty class.) The empty class []
1853            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1854            The negative empty class [^] matches any one character, independently
1855            of the DOTALL setting.
1857    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1858        non-existent subpattern following a character class starting with ']' and
1859        containing () gave an internal compiling error instead of "reference to
1860        non-existent subpattern". Fortunately, when the pattern did exist, the
1861        compiled code was correct. (When scanning forwards to check for the
1862        existencd of the subpattern, it was treating the data ']' as terminating
1863        the class, so got the count wrong. When actually compiling, the reference
1864        was subsequently set up correctly.)
1866    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1867        it was being rejected as not supported by pcre_dfa_exec(), even though
1868        other assertions are supported. I have made pcre_dfa_exec() support
1869        (*FAIL).
1871    16. The implementation of 13c above involved the invention of a new opcode,
1872        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1873        cannot be changed at match time, I realized I could make a small
1874        improvement to matching performance by compiling OP_ALLANY instead of
1875        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1876        on the OP_ANY path.
1878    17. Compiling pcretest on Windows with readline support failed without the
1879        following two fixes: (1) Make the unistd.h include conditional on
1880        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1882    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1883        ncurses library to be included for pcretest when ReadLine support is
1884        requested, but also to allow for it to be overridden. This patch came from
1885        Daniel Bergström.
1887    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1888        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1889        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1890        spotting this.
1893    Version 7.6 28-Jan-08
1894    ---------------------
1896    1.  A character class containing a very large number of characters with
1897        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1898        overflow.
1900    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1901        HAVE_LONG_LONG is not defined.
1903    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1904        bring them up to date and include new features. This patch includes:
1906        - Fixed PH's badly added libz and libbz2 support.
1907        - Fixed a problem with static linking.
1908        - Added pcredemo. [But later removed - see 7 below.]
1909        - Fixed dftables problem and added an option.
1910        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1911            HAVE_LONG_LONG.
1912        - Added readline support for pcretest.
1913        - Added an listing of the option settings after cmake has run.
1915    4.  A user submitted a patch to Makefile that makes it easy to create
1916        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1917        Makefile.am that cause it to include this special target, without
1918        affecting anything else. Note that the same mingw target plus all
1919        the other distribution libraries and programs are now supported
1920        when configuring with CMake (see 6 below) instead of with
1921        Configure/Make.
1923    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1924        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1925        exported in the Windows port". It has not yet been confirmed that the patch
1926        solves the problem, but it does no harm.
1928    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1929        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1930        with CMake, and also correct the comment about stack recursion.
1932    7.  Remove the automatic building of pcredemo from the ./configure system and
1933        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1934        of a program that users should build themselves after PCRE is installed, so
1935        building it automatically is not really right. What is more, it gave
1936        trouble in some build environments.
1938    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1941    Version 7.5 10-Jan-08
1942    ---------------------
1944    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1945        values in parens when parsing an RE using the C++ wrapper."
1947    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1948        Characters greater than 255 were excluded from the class instead of being
1949        included.
1951    3.  The same bug as (2) above applied to negated POSIX classes such as
1952        [:^space:].
1954    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1955        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1956        I have changed it.
1958    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1959        first named subpattern) and a construct such as (?&a) would reference the
1960        first named subpattern whose name started with "a" (in other words, the
1961        length check was missing). Both these problems are fixed. "Subpattern name
1962        expected" is now given for (?&) (a zero-length name), and this patch also
1963        makes it give the same error for \k'' (previously it complained that that
1964        was a reference to a non-existent subpattern).
1966    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1967        this is right because (?- can be followed by option settings as well as by
1968        digits. I have, however, made the messages clearer.
1970    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1971        than the number used in the conditional) now cause a compile-time error.
1972        This is actually not compatible with Perl, which accepts such patterns, but
1973        treats the conditional as always being FALSE (as PCRE used to), but it
1974        seems to me that giving a diagnostic is better.
1976    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1977        and messages.
1979    9.  Fix two occurrences of "backslash" in comments that should have been
1980        "backspace".
1982    10. Remove two redundant lines of code that can never be obeyed (their function
1983        was moved elsewhere).
1985    11. The program that makes PCRE's Unicode character property table had a bug
1986        which caused it to generate incorrect table entries for sequences of
1987        characters that have the same character type, but are in different scripts.
1988        It amalgamated them into a single range, with the script of the first of
1989        them. In other words, some characters were in the wrong script. There were
1990        thirteen such cases, affecting characters in the following ranges:
1992          U+002b0 - U+002c1
1993          U+0060c - U+0060d
1994          U+0061e - U+00612
1995          U+0064b - U+0065e
1996          U+0074d - U+0076d
1997          U+01800 - U+01805
1998          U+01d00 - U+01d77
1999          U+01d9b - U+01dbf
2000          U+0200b - U+0200f
2001          U+030fc - U+030fe
2002          U+03260 - U+0327f
2003          U+0fb46 - U+0fbb1
2004          U+10450 - U+1049d
2006    12. The -o option (show only the matching part of a line) for pcregrep was not
2007        compatible with GNU grep in that, if there was more than one match in a
2008        line, it showed only the first of them. It now behaves in the same way as
2009        GNU grep.
2011    13. If the -o and -v options were combined for pcregrep, it printed a blank
2012        line for every non-matching line. GNU grep prints nothing, and pcregrep now
2013        does the same. The return code can be used to tell if there were any
2014        non-matching lines.
2016    14. Added --file-offsets and --line-offsets to pcregrep.
2018    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
2019        infinitely looping recursion. The bug was that positive lookaheads were not
2020        being skipped when checking for a possible empty match (negative lookaheads
2021        and both kinds of lookbehind were skipped).
2023    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
2024        inclusion of <windows.h> to before rather than after the definition of
2025        INVALID_FILE_ATTRIBUTES (patch from David Byron).
2027    17. Specifying a possessive quantifier with a specific limit for a Unicode
2028        character property caused pcre_compile() to compile bad code, which led at
2029        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
2030        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
2031        caused the error; without that there was no problem.
2033    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
2035    19. Added --enable-pcretest-libreadline.
2037    20. In pcrecpp.cc, the variable 'count' was incremented twice in
2038        RE::GlobalReplace(). As a result, the number of replacements returned was
2039        double what it should be. I removed one of the increments, but Craig sent a
2040        later patch that removed the other one (the right fix) and added unit tests
2041        that check the return values (which was not done before).
2043    21. Several CMake things:
2045        (1) Arranged that, when cmake is used on Unix, the libraries end up with
2046            the names libpcre and libpcreposix, not just pcre and pcreposix.
2048        (2) The above change means that pcretest and pcregrep are now correctly
2049            linked with the newly-built libraries, not previously installed ones.
2053    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
2054        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
2055        UTF-8 newline character). The key issue is that the pattern starts .*;
2056        this means that the match must be either at the beginning, or after a
2057        newline. The bug was in the code for advancing after a failed match and
2058        checking that the new position followed a newline. It was not taking
2059        account of UTF-8 characters correctly.
2061    23. PCRE was behaving differently from Perl in the way it recognized POSIX
2062        character classes. PCRE was not treating the sequence [:...:] as a
2063        character class unless the ... were all letters. Perl, however, seems to
2064        allow any characters between [: and :], though of course it rejects as
2065        unknown any "names" that contain non-letters, because all the known class
2066        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
2067        for example, whereas PCRE did not - it did not recognize a POSIX character
2068        class. This seemed a bit dangerous, so the code has been changed to be
2069        closer to Perl. The behaviour is not identical to Perl, because PCRE will
2070        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
2071        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
2072        Perl does, and where it didn't before.
2074    24. Rewrite so as to remove the single use of %n from pcregrep because in some
2075        Windows environments %n is disabled by default.
2078    Version 7.4 21-Sep-07
2079    ---------------------
2081    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
2082        means that a class such as [\s] counted as "explicit reference to CR or
2083        LF". That isn't really right - the whole point of the change was to try to
2084        help when there was an actual mention of one of the two characters. So now
2085        the change happens only if \r or \n (or a literal CR or LF) character is
2086        encountered.
2088    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
2089        of both had grown to the point where there were only 3 bits left.
2090        Fortunately, there was spare space in the data structure, and so I have
2091        moved the internal flags into a new 16-bit field to free up more option
2092        bits.
2094    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
2095        but did not set the internal JCHANGED flag - either of these is enough to
2096        control the way the "get" function works - but the PCRE_INFO_JCHANGED
2097        facility is supposed to tell if (?J) was ever used, so now (?J) at the
2098        start sets both bits.
2100    4.  Added options (at build time, compile time, exec time) to change \R from
2101        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
2103    5.  doc/pcresyntax.html was missing from the distribution.
2105    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
2106        compatibility, even though it is no longer used.
2108    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
2109        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
2110        windows.h file is present (where different names are used). [This was
2111        reversed later after testing - see 16 below.]
2113    8.  Changed all #include <config.h> to #include "config.h". There were also
2114        some further <pcre.h> cases that I changed to "pcre.h".
2116    9.  When pcregrep was used with the --colour option, it missed the line ending
2117        sequence off the lines that it output.
2119    10. It was pointed out to me that arrays of string pointers cause lots of
2120        relocations when a shared library is dynamically loaded. A technique of
2121        using a single long string with a table of offsets can drastically reduce
2122        these. I have refactored PCRE in four places to do this. The result is
2123        dramatic:
2125          Originally:                          290
2126          After changing UCP table:            187
2127          After changing error message table:   43
2128          After changing table of "verbs"       36
2129          After changing table of Posix names   22
2131        Thanks to the folks working on Gregex for glib for this insight.
2133    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
2134        unicode-properties was also set.
2136    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
2138    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
2139        checked only for CRLF.
2141    14. Added casts to pcretest.c to avoid compiler warnings.
2143    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
2145    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
2146        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
2147        entirely. This removes changes made in 7 above.
2149    17. The CMake files have been updated, and there is now more information about
2150        building with CMake in the NON-UNIX-USE document.
2153    Version 7.3 28-Aug-07
2154    ---------------------
2156     1. In the rejigging of the build system that eventually resulted in 7.1, the
2157        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
2158        brackets there is not right, since it causes compilers to look for an
2159        installed pcre.h, not the version that is in the source that is being
2160        compiled (which of course may be different). I have changed it back to:
2162          #include "pcre.h"
2164        I have a vague recollection that the change was concerned with compiling in
2165        different directories, but in the new build system, that is taken care of
2166        by the VPATH setting the Makefile.
2168     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
2169        when the subject happened to end in the byte 0x85 (e.g. if the last
2170        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
2171        characters but of course it shouldn't be taken as a newline when it is part
2172        of another character. The bug was that, for an unlimited repeat of . in
2173        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
2174        characters when looking for a newline.
2176     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
2178     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
2179        in debug output.
2181     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
2182        long printing in the pcrecpp unittest when running under MinGW.
2184     6. ESC_K was left out of the EBCDIC table.
2186     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
2187        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
2188        limit also applies to "virtual nesting" when a pattern is recursive, and in
2189        this case 1000 isn't so big. I have been able to remove this limit at the
2190        expense of backing off one optimization in certain circumstances. Normally,
2191        when pcre_exec() would call its internal match() function recursively and
2192        immediately return the result unconditionally, it uses a "tail recursion"
2193        feature to save stack. However, when a subpattern that can match an empty
2194        string has an unlimited repetition quantifier, it no longer makes this
2195        optimization. That gives it a stack frame in which to save the data for
2196        checking that an empty string has been matched. Previously this was taken
2197        from the 1000-entry workspace that had been reserved. So now there is no
2198        explicit limit, but more stack is used.
2200     8. Applied Daniel's patches to solve problems with the import/export magic
2201        syntax that is required for Windows, and which was going wrong for the
2202        pcreposix and pcrecpp parts of the library. These were overlooked when this
2203        problem was solved for the main library.
2205     9. There were some crude static tests to avoid integer overflow when computing
2206        the size of patterns that contain repeated groups with explicit upper
2207        limits. As the maximum quantifier is 65535, the maximum group length was
2208        set at 30,000 so that the product of these two numbers did not overflow a
2209        32-bit integer. However, it turns out that people want to use groups that
2210        are longer than 30,000 bytes (though not repeat them that many times).
2211        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
2212        made it possible to implement the integer overflow checks in a much more
2213        dynamic way, which I have now done. The artificial limitation on group
2214        length has been removed - we now have only the limit on the total length of
2215        the compiled pattern, which depends on the LINK_SIZE setting.
2217    10. Fixed a bug in the documentation for get/copy named substring when
2218        duplicate names are permitted. If none of the named substrings are set, the
2219        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
2220        empty string.
2222    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
2223        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
2224        because the ] is interpreted as the first data character and the
2225        terminating ] is not found. PCRE has been made compatible with Perl in this
2226        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
2227        cause memory overwriting.
2229    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
2230        string has been matched (to stop an infinite loop). It was not recognizing
2231        a conditional subpattern that could match an empty string if that
2232        subpattern was within another subpattern. For example, it looped when
2233        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
2234        condition was not nested. This bug has been fixed.
2236    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
2237        past the start of the subject in the presence of bytes with the top bit
2238        set, for example "\x8aBCD".
2240    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
2241        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
2243    14. Optimized (?!) to (*FAIL).
2245    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
2246        This restricts code points to be within the range 0 to 0x10FFFF, excluding
2247        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
2248        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
2249        does: it's just the validity check that is more restrictive.
2251    16. Inserted checks for integer overflows during escape sequence (backslash)
2252        processing, and also fixed erroneous offset values for syntax errors during
2253        backslash processing.
2255    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
2256        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
2258    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
2259        caused an overrun.
2261    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
2262        something other than just ASCII characters) inside a group that had an
2263        unlimited repeat caused a loop at compile time (while checking to see
2264        whether the group could match an empty string).
2266    20. Debugging a pattern containing \p or \P could cause a crash. For example,
2267        [\P{Any}] did so. (Error in the code for printing property names.)
2269    21. An orphan \E inside a character class could cause a crash.
2271    22. A repeated capturing bracket such as (A)? could cause a wild memory
2272        reference during compilation.
2274    23. There are several functions in pcre_compile() that scan along a compiled
2275        expression for various reasons (e.g. to see if it's fixed length for look
2276        behind). There were bugs in these functions when a repeated \p or \P was
2277        present in the pattern. These operators have additional parameters compared
2278        with \d, etc, and these were not being taken into account when moving along
2279        the compiled data. Specifically:
2281        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
2282            length.
2284        (b) An item such as \pL+ within a repeated group could cause crashes or
2285            loops.
2287        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
2288            "reference to non-existent subpattern" error.
2290        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
2292    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
2293        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
2295    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
2297    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
2298        character were causing crashes (broken optimization).
2300    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
2301        \p or \P) caused a compile-time loop.
2303    28. More problems have arisen in unanchored patterns when CRLF is a valid line
2304        break. For example, the unstudied pattern [\r\n]A does not match the string
2305        "\r\nA" because change 7.0/46 below moves the current point on by two
2306        characters after failing to match at the start. However, the pattern \nA
2307        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
2308        the same is true. There doesn't seem any very clean way out of this, but
2309        what I have chosen to do makes the common cases work: PCRE now takes note
2310        of whether there can be an explicit match for \r or \n anywhere in the
2311        pattern, and if so, 7.0/46 no longer applies. As part of this change,
2312        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
2313        pattern has explicit CR or LF references.
2315    29. Added (*CR) etc for changing newline setting at start of pattern.
2318    Version 7.2 19-Jun-07
2319    ---------------------
2321     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
2322        which is apparently normally available under Windows.
2324     2. Re-jig the pcregrep tests with different newline settings in an attempt
2325        to make them independent of the local environment's newline setting.
2327     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
2329     4. Some of the "internals" tests were previously cut out when the link size
2330        was not 2, because the output contained actual offsets. The recent new
2331        "Z" feature of pcretest means that these can be cut out, making the tests
2332        usable with all link sizes.
2334     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
2335        stack recursion. This gives a massive performance boost under BSD, but just
2336        a small improvement under Linux. However, it saves one field in the frame
2337        in all cases.
2339     6. Added more features from the forthcoming Perl 5.10:
2341        (a) (?-n) (where n is a string of digits) is a relative subroutine or
2342            recursion call. It refers to the nth most recently opened parentheses.
2344        (b) (?+n) is also a relative subroutine call; it refers to the nth next
2345            to be opened parentheses.
2347        (c) Conditions that refer to capturing parentheses can be specified
2348            relatively, for example, (?(-2)... or (?(+3)...
2350        (d) \K resets the start of the current match so that everything before
2351            is not part of it.
2353        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
2355        (f) \g{name} is another synonym - part of Perl 5.10's unification of
2356            reference syntax.
2358        (g) (?| introduces a group in which the numbering of parentheses in each
2359            alternative starts with the same number.
2361        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
2363     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
2366     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
2367        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
2368        for detecting groups that can match an empty string.
2370     9. A pattern with a very large number of alternatives (more than several
2371        hundred) was running out of internal workspace during the pre-compile
2372        phase, where pcre_compile() figures out how much memory will be needed. A
2373        bit of new cunning has reduced the workspace needed for groups with
2374        alternatives. The 1000-alternative test pattern now uses 12 bytes of
2375        workspace instead of running out of the 4096 that are available.
2377    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
2379    11. Applied patch from Google to remove an optimization that didn't quite work.
2380        The report of the bug said:
2382          pcrecpp::RE("a*").FullMatch("aaa") matches, while
2383          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
2384          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
2386    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
2387        it matched the wrong number of bytes.
2390    Version 7.1 24-Apr-07
2391    ---------------------
2393     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
2394        that is more "standard", making use of automake and other Autotools. There
2395        is some re-arrangement of the files and adjustment of comments consequent
2396        on this.
2398     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
2399        for recursive directory scanning broke on some systems because the files
2400        are not scanned in any specific order and on different systems the order
2401        was different. A call to "sort" has been inserted into RunGrepTest for the
2402        approprate test as a short-term fix. In the longer term there may be an
2403        alternative.
2405     3. I had an email from Eric Raymond about problems translating some of PCRE's
2406        man pages to HTML (despite the fact that I distribute HTML pages, some
2407        people do their own conversions for various reasons). The problems
2408        concerned the use of low-level troff macros .br and .in. I have therefore
2409        removed all such uses from the man pages (some were redundant, some could
2410        be replaced by .nf/.fi pairs). The 132html script that I use to generate
2411        HTML has been updated to handle .nf/.fi and to complain if it encounters
2412        .br or .in.
2414     4. Updated comments in configure.ac that get placed in config.h.in and also
2415        arranged for config.h to be included in the distribution, with the name
2416        config.h.generic, for the benefit of those who have to compile without
2417        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
2419     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
2420        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
2421        makevp.bat for the current PCRE, using the additional files
2422        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
2424     6. A Windows user reported a minor discrepancy with test 2, which turned out
2425        to be caused by a trailing space on an input line that had got lost in his
2426        copy. The trailing space was an accident, so I've just removed it.
2428     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
2429        that is needed.
2431     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
2432        as "const" (a) because they are and (b) because it helps the PHP
2433        maintainers who have recently made a script to detect big data structures
2434        in the php code that should be moved to the .rodata section. I remembered
2435        to update Builducptable as well, so it won't revert if ucptable.h is ever
2436        re-created.
2438     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
2439        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
2440        order to be able to cut out the UTF-8 tables in the latter when UTF-8
2441        support is not required. This saves 1.5-2K of code, which is important in
2442        some applications.
2444        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
2445        so as not to refer to the tables, even though these functions will never be
2446        called when UTF-8 support is disabled. Otherwise there are problems with a
2447        shared library.
2449    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
2451        (a) It was defining its arguments as char * instead of void *.
2453        (b) It was assuming that all moves were upwards in memory; this was true
2454            a long time ago when I wrote it, but is no longer the case.
2456        The emulated memove() is provided for those environments that have neither
2457        memmove() nor bcopy(). I didn't think anyone used it these days, but that
2458        is clearly not the case, as these two bugs were recently reported.
2460    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
2461        and Detrail to create the HTML documentation, the .txt form of the man
2462        pages, and it removes trailing spaces from listed files. It also creates
2463        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
2464        case, it wraps all the #defines with #ifndefs. This script should be run
2465        before "make dist".
2467    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
2468        with Unicode property support.
2470        (a) For a maximizing quantifier, if the two different cases of the
2471            character were of different lengths in their UTF-8 codings (there are
2472            some cases like this - I found 11), and the matching function had to
2473            back up over a mixture of the two cases, it incorrectly assumed they
2474            were both the same length.
2476        (b) When PCRE was configured to use the heap rather than the stack for
2477            recursion during matching, it was not correctly preserving the data for
2478            the other case of a UTF-8 character when checking ahead for a match
2479            while processing a minimizing repeat. If the check also involved
2480            matching a wide character, but failed, corruption could cause an
2481            erroneous result when trying to check for a repeat of the original
2482            character.
2484    13. Some tidying changes to the testing mechanism:
2486        (a) The RunTest script now detects the internal link size and whether there
2487            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
2488            values substituted by "configure". (The RunGrepTest script already did
2489            this for UTF-8.) The configure.ac script no longer substitutes the
2490            relevant variables.
2492        (b) The debugging options /B and /D in pcretest show the compiled bytecode
2493            with length and offset values. This means that the output is different
2494            for different internal link sizes. Test 2 is skipped for link sizes
2495            other than 2 because of this, bypassing the problem. Unfortunately,
2496            there was also a test in test 3 (the locale tests) that used /B and
2497            failed for link sizes other than 2. Rather than cut the whole test out,
2498            I have added a new /Z option to pcretest that replaces the length and
2499            offset values with spaces. This is now used to make test 3 independent
2500            of link size. (Test 2 will be tidied up later.)
2502    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2503        segmentation fault instead of returning the appropriate error message.
2505    15. In multiline mode when the newline sequence was set to "any", the pattern
2506        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2507        This doesn't seem right; it now treats the CRLF combination as the line
2508        ending, and so does not match in that case. It's only a pattern such as ^$
2509        that would hit this one: something like ^ABC$ would have failed after \r
2510        and then tried again after \r\n.
2512    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2513        in an attempt to make files that differ only in their line terminators
2514        compare equal. This works on Linux.
2516    17. Under certain error circumstances pcregrep might try to free random memory
2517        as it exited. This is now fixed, thanks to valgrind.
2519    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2520        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2521        was because its rules for how to advance for /g after matching an empty
2522        string at the end of a line did not allow for this case. They now check for
2523        it specially.
2525    20. pcretest is supposed to handle patterns and data of any length, by
2526        extending its buffers when necessary. It was getting this wrong when the
2527        buffer for a data line had to be extended.
2529    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2530        CRLF as a newline sequence.
2532    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2533        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2534        I have nevertheless tidied it up.
2536    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2538    24. Added a man page for pcre-config.
2541    Version 7.0 19-Dec-06
2542    ---------------------
2544     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2545        moving to gcc 4.1.1.
2547     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2548        sys/time.h, which is documented as needed for this function. It doesn't
2549        seem to matter on Linux, but it showed up on some releases of OS X.
2551     3. It seems that there are systems where bytes whose values are greater than
2552        127 match isprint() in the "C" locale. The "C" locale should be the
2553        default when a C program starts up. In most systems, only ASCII printing
2554        characters match isprint(). This difference caused the output from pcretest
2555        to vary, making some of the tests fail. I have changed pcretest so that:
2557        (a) When it is outputting text in the compiled version of a pattern, bytes
2558            other than 32-126 are always shown as hex escapes.
2560        (b) When it is outputting text that is a matched part of a subject string,
2561            it does the same, unless a different locale has been set for the match
2562            (using the /L modifier). In this case, it uses isprint() to decide.
2564     4. Fixed a major bug that caused incorrect computation of the amount of memory
2565        required for a compiled pattern when options that changed within the
2566        pattern affected the logic of the preliminary scan that determines the
2567        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2568        that the computed length was too small. The symptoms of this bug were
2569        either the PCRE error "internal error: code overflow" from pcre_compile(),
2570        or a glibc crash with a message such as "pcretest: free(): invalid next
2571        size (fast)". Examples of patterns that provoked this bug (shown in
2572        pcretest format) are:
2574          /(?-x: )/x
2575          /(?x)(?-x: \s*#\s*)/
2576          /((?i)[\x{c0}])/8
2577          /(?i:[\x{c0}])/8
2579        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2580        is now done differently.
2582     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2583        wrapper classes; (b) implement a new function in the C++ scanner that is
2584        more efficient than the old way of doing things because it avoids levels of
2585        recursion in the regex matching; (c) add a paragraph to the documentation
2586        for the FullMatch() function.
2588     6. The escape sequence \n was being treated as whatever was defined as
2589        "newline". Not only was this contrary to the documentation, which states
2590        that \n is character 10 (hex 0A), but it also went horribly wrong when
2591        "newline" was defined as CRLF. This has been fixed.
2593     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2594        was being set to -1 for the "end of line" case (supposedly a value that no
2595        character can have). Though this value is never used (the check for end of
2596        line is "zero bytes in current character"), it caused compiler complaints.
2597        I've changed it to 0xffffffff.
2599     8. In pcre_version.c, the version string was being built by a sequence of
2600        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2601        string (as it is for production releases) called a macro with an empty
2602        argument. The C standard says the result of this is undefined. The gcc
2603        compiler treats it as an empty string (which was what was wanted) but it is
2604        reported that Visual C gives an error. The source has been hacked around to
2605        avoid this problem.
2607     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2608        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2609        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2610        of them did).
2612    10. Originally, pcretest opened its input and output without "b"; then I was
2613        told that "b" was needed in some environments, so it was added for release
2614        5.0 to both the input and output. (It makes no difference on Unix-like
2615        systems.) Later I was told that it is wrong for the input on Windows. I've
2616        now abstracted the modes into two macros, to make it easier to fiddle with
2617        them, and removed "b" from the input mode under Windows.
2619    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2621    12. Added -help and --help to pcretest as an official way of being reminded
2622        of the options.
2624    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2625        and pcrecpp.cc because they annoy compilers at high warning levels.
2627    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2629    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2630        scripts are not C programs :-) and which was not noticed because it works
2631        on Linux.
2633    16. pcretest is supposed to handle any length of pattern and data line (as one
2634        line or as a continued sequence of lines) by extending its input buffer if
2635        necessary. This feature was broken for very long pattern lines, leading to
2636        a string of junk being passed to pcre_compile() if the pattern was longer
2637        than about 50K.
2639    17. I have done a major re-factoring of the way pcre_compile() computes the
2640        amount of memory needed for a compiled pattern. Previously, there was code
2641        that made a preliminary scan of the pattern in order to do this. That was
2642        OK when PCRE was new, but as the facilities have expanded, it has become
2643        harder and harder to keep it in step with the real compile phase, and there
2644        have been a number of bugs (see for example, 4 above). I have now found a
2645        cunning way of running the real compile function in a "fake" mode that
2646        enables it to compute how much memory it would need, while actually only
2647        ever using a few hundred bytes of working memory and without too many
2648        tests of the mode. This should make future maintenance and development
2649        easier. A side effect of this work is that the limit of 200 on the nesting
2650        depth of parentheses has been removed (though this was never a serious
2651        limitation, I suspect). However, there is a downside: pcre_compile() now
2652        runs more slowly than before (30% or more, depending on the pattern). I
2653        hope this isn't a big issue. There is no effect on runtime performance.
2655    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2656        newline (only possible for the last line of a file) and it was a
2657        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2659    19. Added additional timing features to pcretest. (1) The -tm option now times
2660        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2661        separate command line item, by a number that specifies the number of
2662        repeats to use when timing. The default is 50000; this gives better
2663        precision, but takes uncomfortably long for very large patterns.
2665    20. Extended pcre_study() to be more clever in cases where a branch of a
2666        subpattern has no definite first character. For example, (a*|b*)[cd] would
2667        previously give no result from pcre_study(). Now it recognizes that the
2668        first character must be a, b, c, or d.
2670    21. There was an incorrect error "recursive call could loop indefinitely" if
2671        a subpattern (or the entire pattern) that was being tested for matching an
2672        empty string contained only one non-empty item after a nested subpattern.
2673        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2674        incorrectly, because the \d was being skipped in the check.
2676    22. The pcretest program now has a new pattern option /B and a command line
2677        option -b, which is equivalent to adding /B to every pattern. This causes
2678        it to show the compiled bytecode, without the additional information that
2679        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2680        is the same as /B/I).
2682    23. A new optimization is now able automatically to treat some sequences such
2683        as a*b as a*+b. More specifically, if something simple (such as a character
2684        or a simple class like \d) has an unlimited quantifier, and is followed by
2685        something that cannot possibly match the quantified thing, the quantifier
2686        is automatically "possessified".
2688    24. A recursive reference to a subpattern whose number was greater than 39
2689        went wrong under certain circumstances in UTF-8 mode. This bug could also
2690        have affected the operation of pcre_study().
2692    25. Realized that a little bit of performance could be had by replacing
2693        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2695    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2697    27. Possessive quantifiers such as a++ were previously implemented by turning
2698        them into atomic groups such as ($>a+). Now they have their own opcodes,
2699        which improves performance. This includes the automatically created ones
2700        from 23 above.
2702    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2703        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2704        the first matched character to be a colon. This applied both to named and
2705        numbered groups.
2707    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2709    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2710        building PCRE on Windows easier, so I have included it in the distribution.
2712    31. There is now a check in pcretest against a ridiculously large number being
2713        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2714        loop, the loop is abandoned.
2716    32. Forward references to subpatterns in conditions such as (?(2)...) where
2717        subpattern 2 is defined later cause pcre_compile() to search forwards in
2718        the pattern for the relevant set of parentheses. This search went wrong
2719        when there were unescaped parentheses in a character class, parentheses
2720        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2722    33. "Subroutine" calls and backreferences were previously restricted to
2723        referencing subpatterns earlier in the regex. This restriction has now
2724        been removed.
2726    34. Added a number of extra features that are going to be in Perl 5.10. On the
2727        whole, these are just syntactic alternatives for features that PCRE had
2728        previously implemented using the Python syntax or my own invention. The
2729        other formats are all retained for compatibility.
2731        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2732            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2733            also .NET compatible.
2735        (b) A recursion or subroutine call to a named group can now be defined as
2736            (?&name) as well as (?P>name).
2738        (c) A backreference to a named group can now be defined as \k<name> or
2739            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2740            5.10, are also .NET compatible.
2742        (d) A conditional reference to a named group can now use the syntax
2743            (?(<name>) or (?('name') as well as (?(name).
2745        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2746            groups (named and numbered) that are never evaluated inline, but can be
2747            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2748            is always false. There may be only one alternative in such a group.
2750        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2751            as the simple (?(R). The condition is true only if the most recent
2752            recursion is that of the given number or name. It does not search out
2753            through the entire recursion stack.
2755        (g) The escape \gN or \g{N} has been added, where N is a positive or
2756            negative number, specifying an absolute or relative reference.
2758    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2759        some "unreachable code" warnings.
2761    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2762        things, this adds five new scripts.
2764    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2765        There were also incompatibilities regarding the handling of \Q..\E inside
2766        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2767        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2769    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2770        matches an empty string, and forcibly breaks the loop. There were bugs in
2771        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2772        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2773        separate and independent bugs (that affected different cases) have been
2774        fixed.
2776    39. Refactored the code to abolish the use of different opcodes for small
2777        capturing bracket numbers. This is a tidy that I avoided doing when I
2778        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2779        The new approach is not only tidier, it makes it possible to reduce the
2780        memory needed to fix the previous bug (38).
2782    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2783        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2784        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2785        mode.
2787    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2788        report.
2790    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2791        copy construction and assignment in the C++ wrapper.
2793    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2794        couple of bugs that could have given wrong results in the "--newline=crlf"
2795        case.
2797    44. Added a number of casts and did some reorganization of signed/unsigned int
2798        variables following suggestions from Dair Grant. Also renamed the variable
2799        "this" as "item" because it is a C++ keyword.
2801    45. Arranged for dftables to add
2803          #include "pcre_internal.h"
2805        to pcre_chartables.c because without it, gcc 4.x may remove the array
2806        definition from the final binary if PCRE is built into a static library and
2807        dead code stripping is activated.
2809    46. For an unanchored pattern, if a match attempt fails at the start of a
2810        newline sequence, and the newline setting is CRLF or ANY, and the next two
2811        characters are CRLF, advance by two characters instead of one.
2814  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
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