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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.34 xx-xxxx-201x
5    --------------------------
7    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
8        executable memory. Patch inspired by Carsten Klein.
11    Version 8.33 28-May-2013
12    --------------------------
14    1.  Added 'U' to some constants that are compared to unsigned integers, to
15        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
16        variables that are added to signed variables, to ensure the result is
17        signed and can be negated.
19    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
20        CMake config files.
22    3.  Revise the creation of config.h.generic so that all boolean macros are
23        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
24        overriding via -D on the command line possible.
26    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
27        to unsigned int is reported to make a quite noticeable speed difference in
28        a specific Windows environment. Testing on Linux did also appear to show
29        some benefit (and it is clearly not harmful). Also fixed the definition of
30        Xop which should be unsigned.
32    5.  Related to (4), changing the definition of the intermediate variable cc
33        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
34        improvements.
36    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
37        unnecessary spaces.
39    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
40        and later.
42    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
44    9.  Optimizing fast_forward_start_bits in JIT.
46    10. Adding support for callouts in JIT, and fixing some issues revealed
47        during this work. Namely:
49        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
51        (b) Minimum length was not checked before the matching is started.
53    11. The value of capture_last that is passed to callouts was incorrect in some
54        cases when there was a capture on one path that was subsequently abandoned
55        after a backtrack. Also, the capture_last value is now reset after a
56        recursion, since all captures are also reset in this case.
58    12. The interpreter no longer returns the "too many substrings" error in the
59        case when an overflowing capture is in a branch that is subsequently
60        abandoned after a backtrack.
62    13. In the pathological case when an offset vector of size 2 is used, pcretest
63        now prints out the matched string after a yield of 0 or 1.
65    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
66        Only supported by the JIT compiler at the moment.
68    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
70    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
71        offset of the starting point of the matching process, provided the offsets
72        vector is large enough.
74    17. The \A escape now records a lookbehind value of 1, though its execution
75        does not actually inspect the previous character. This is to ensure that,
76        in partial multi-segment matching, at least one character from the old
77        segment is retained when a new segment is processed. Otherwise, if there
78        are no lookbehinds in the pattern, \A might match incorrectly at the start
79        of a new segment.
81    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
83    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
84        gives some modest performance improvement in 8-bit mode.
86    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
87        be expressed in certain programming languages using Universal Character
88        Names.
90    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
91        which points out that "non characters" are not "characters that may not
92        appear in Unicode strings" but rather "characters that are reserved for
93        internal use and have only local meaning".
95    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
96        there was a conditional group that depended on an assertion, if the
97        assertion was false, the callout that immediately followed the alternation
98        in the condition was skipped when pcre_exec() was used for matching.
100    23. Allow an explicit callout to be inserted before an assertion that is the
101        condition for a conditional group, for compatibility with automatic
102        callouts, which always insert a callout at this point.
104    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
105        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
107    25. (*PRUNE) is now supported by the JIT compiler.
109    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
111    27. Fix the case where there are two or more SKIPs with arguments that may be
112        ignored.
114    28. (*SKIP) is now supported by the JIT compiler.
116    29. (*THEN) is now supported by the JIT compiler.
118    30. Update RunTest with additional test selector options.
120    31. The way PCRE handles backtracking verbs has been changed in two ways.
122        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
123        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
124        backtracking. In some cases this makes it more Perl-compatible, but Perl's
125        rather obscure rules do not always do the same thing.
127        (2) Previously, backtracking verbs were confined within assertions. This is
128        no longer the case for positive assertions, except for (*ACCEPT). Again,
129        this sometimes improves Perl compatibility, and sometimes does not.
131    32. A number of tests that were in test 2 because Perl did things differently
132        have been moved to test 1, because either Perl or PCRE has changed, and
133        these tests are now compatible.
135    32. Backtracking control verbs are now handled in the same way in JIT and
136        interpreter.
138    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
139        contained a forward subroutine reference caused a compile error.
141    34. Auto-detect and optimize limited repetitions in JIT.
143    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
144        blocking (*UTF) etc.
146    36. In the interpreter, maximizing pattern repetitions for characters and
147        character types now use tail recursion, which reduces stack usage.
149    37. The value of the max lookbehind was not correctly preserved if a compiled
150        and saved regex was reloaded on a host of different endianness.
152    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
153        of the compiled pattern block, expand the flags field from 16 to 32 bits
154        because it was almost full.
156    39. Try madvise first before posix_madvise.
158    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
159        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
160        original change locked out all matches of empty strings. This has been
161        changed so that one match of an empty string per line is recognized.
162        Subsequent searches on the same line (for colouring or for --only-matching,
163        for example) do not recognize empty strings.
165    41. Applied a user patch to fix a number of spelling mistakes in comments.
167    42. Data lines longer than 65536 caused pcretest to crash.
169    43. Clarified the data type for length and startoffset arguments for pcre_exec
170        and pcre_dfa_exec in the function-specific man pages, where they were
171        explicitly stated to be in bytes, never having been updated. I also added
172        some clarification to the pcreapi man page.
174    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
175        a segmentation fault.
178    Version 8.32 30-November-2012
179    -----------------------------
181    1.  Improved JIT compiler optimizations for first character search and single
182        character iterators.
184    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
185        Patch by Daniel Richard G.
187    3.  Single character iterator optimizations in the JIT compiler.
189    4.  Improved JIT compiler optimizations for character ranges.
191    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
192        Reported by Giuseppe D'Angelo.
194    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
195        of a line, was being set incorrectly in cases where .* appeared inside
196        atomic brackets at the start of a pattern, or where there was a subsequent
197        *PRUNE or *SKIP.
199    7.  Improved instruction cache flush for POWER/PowerPC.
200        Patch by Daniel Richard G.
202    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
203        grep:
205        (a) There is now no limit to the number of patterns to be matched.
207        (b) An error is given if a pattern is too long.
209        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
210            are now supported.
212        (d) --exclude-from and --include-from (multiple use) have been added.
214        (e) Exclusions and inclusions now apply to all files and directories, not
215            just to those obtained from scanning a directory recursively.
217        (f) Multiple uses of -f and --file-list are now supported.
219        (g) In a Windows environment, the default for -d has been changed from
220            "read" (the GNU grep default) to "skip", because otherwise the presence
221            of a directory in the file list provokes an error.
223        (h) The documentation has been revised and clarified in places.
225    9.  Improve the matching speed of capturing brackets.
227    10. Changed the meaning of \X so that it now matches a Unicode extended
228        grapheme cluster.
230    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
231        out POSIX threads when JIT support is configured.
233    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
235    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
236        structure could go wrong in environments where size_t is not the same size
237        as int.
239    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
240        set.
242    15. The EBCDIC support had decayed; later updates to the code had included
243        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
244        general tidy up of EBCDIC-related issues, and the documentation was also
245        not quite right. There is now a test that can be run on ASCII systems to
246        check some of the EBCDIC-related things (but is it not a full test).
248    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
249        in a small tidy to the code.
251    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
253    18. If the --only-matching (-o) option in pcregrep is specified multiple
254        times, each one causes appropriate output. For example, -o1 -o2 outputs the
255        substrings matched by the 1st and 2nd capturing parentheses. A separating
256        string can be specified by --om-separator (default empty).
258    19. Improving the first n character searches.
260    20. Turn case lists for horizontal and vertical white space into macros so that
261        they are defined only once.
263    21. This set of changes together give more compatible Unicode case-folding
264        behaviour for characters that have more than one other case when UCP
265        support is available.
267        (a) The Unicode property table now has offsets into a new table of sets of
268            three or more characters that are case-equivalent. The MultiStage2.py
269            script that generates these tables (the pcre_ucd.c file) now scans
270            CaseFolding.txt instead of UnicodeData.txt for character case
271            information.
273        (b) The code for adding characters or ranges of characters to a character
274            class has been abstracted into a generalized function that also handles
275            case-independence. In UTF-mode with UCP support, this uses the new data
276            to handle characters with more than one other case.
278        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
279            whose other case is greater than 256 are now correctly matched
280            caselessly. Previously, the high codepoint matched the low one, but not
281            vice versa.
283        (d) The processing of \h, \H, \v, and \ in character classes now makes use
284            of the new class addition function, using character lists defined as
285            macros alongside the case definitions of 20 above.
287        (e) Caseless back references now work with characters that have more than
288            one other case.
290        (f) General caseless matching of characters with more than one other case
291            is supported.
293    22. Unicode character properties were updated from Unicode 6.2.0
295    23. Improved CMake support under Windows. Patch by Daniel Richard G.
297    24. Add support for 32-bit character strings, and UTF-32
299    25. Major JIT compiler update (code refactoring and bugfixing).
300        Experimental Sparc 32 support is added.
302    26. Applied a modified version of Daniel Richard G's patch to create
303        pcre.h.generic and config.h.generic by "make" instead of in the
304        PrepareRelease script.
306    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
307        pcre_compile.c when checking for a zero character.
309    28. Introducing a native interface for JIT. Through this interface, the compiled
310        machine code can be directly executed. The purpose of this interface is to
311        provide fast pattern matching, so several sanity checks are not performed.
312        However, feature tests are still performed. The new interface provides
313        1.4x speedup compared to the old one.
315    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
316        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
317        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
319    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
320        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
321        the "old" RFC 2279). Instead, it ended up passing a negative length to
322        pcre_exec().
324    31. Add support for GCC's visibility feature to hide internal functions.
326    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
327        "unknown -C option" after outputting 0 or 1.
329    33. There is now support for generating a code coverage report for the test
330        suite in environments where gcc is the compiler and lcov is installed. This
331        is mainly for the benefit of the developers.
333    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
334        unaddressable using valgrind annotations, allowing valgrind to detect
335        invalid memory accesses. This is mainly for the benefit of the developers.
337    25. (*UTF) can now be used to start a pattern in any of the three libraries.
339    26. Give configure error if --enable-cpp but no C++ compiler found.
342    Version 8.31 06-July-2012
343    -------------------------
345    1.  Fixing a wrong JIT test case and some compiler warnings.
347    2.  Removed a bashism from the RunTest script.
349    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
350        to unsigned type, result still unsigned" that was given by an MS compiler
351        on encountering the code "-sizeof(xxx)".
353    4.  Partial matching support is added to the JIT compiler.
355    5.  Fixed several bugs concerned with partial matching of items that consist
356        of more than one character:
358        (a) /^(..)\1/ did not partially match "aba" because checking references was
359            done on an "all or nothing" basis. This also applied to repeated
360            references.
362        (b) \R did not give a hard partial match if \r was found at the end of the
363            subject.
365        (c) \X did not give a hard partial match after matching one or more
366            characters at the end of the subject.
368        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
369            a partial match for the string "\r".
371        (e) When newline was set to CRLF, the metacharacter "." did not recognize
372            a partial match for a CR character at the end of the subject string.
374    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
375        running pcretest, the text "(JIT)" added to the output whenever JIT is
376        actually used to run the match.
378    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
379        or /S+[+] with a digit between 1 and 7.
381    8.  OP_NOT now supports any UTF character not just single-byte ones.
383    9.  (*MARK) control verb is now supported by the JIT compiler.
385    10. The command "./RunTest list" lists the available tests without actually
386        running any of them. (Because I keep forgetting what they all are.)
390    12. Applied a (slightly modified) user-supplied patch that improves performance
391        when the heap is used for recursion (compiled with --disable-stack-for-
392        recursion). Instead of malloc and free for each heap frame each time a
393        logical recursion happens, frames are retained on a chain and re-used where
394        possible. This sometimes gives as much as 30% improvement.
396    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
397        call.
399    14. As documented, (*COMMIT) is now confined to within a positive assertion.
401    15. It is now possible to link pcretest with libedit as an alternative to
402        libreadline.
404    16. (*COMMIT) control verb is now supported by the JIT compiler.
406    17. The Unicode data tables have been updated to Unicode 6.1.0.
408    18. Added --file-list option to pcregrep.
410    19. Added binary file support to pcregrep, including the -a, --binary-files,
411        -I, and --text options.
413    20. The madvise function is renamed for posix_madvise for QNX compatibility
414        reasons. Fixed by Giuseppe D'Angelo.
416    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
418    22. Changed the option for creating symbolic links for 16-bit man pages from
419        -s to -sf so that re-installing does not cause issues.
421    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
423    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
424        matches in certain environments (the workspace was not being correctly
425        retained). Also added to pcre_dfa_exec() a simple plausibility check on
426        some of the workspace data at the beginning of a restart.
428    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
429        was not doing so when it should - probably a typo introduced by SVN 528
430        (change 8.10/14).
432    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
433        \w+ when the character tables indicated that \x{c4} was a word character.
434        There were several related cases, all because the tests for doing a table
435        lookup were testing for characters less than 127 instead of 255.
437    27. If a pattern contains capturing parentheses that are not used in a match,
438        their slots in the ovector are set to -1. For those that are higher than
439        any matched groups, this happens at the end of processing. In the case when
440        there were back references that the ovector was too small to contain
441        (causing temporary malloc'd memory to be used during matching), and the
442        highest capturing number was not used, memory off the end of the ovector
443        was incorrectly being set to -1. (It was using the size of the temporary
444        memory instead of the true size.)
446    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
447        ovector size, it uses memory at the end of the block that it has got.
449    29. Check for an overlong MARK name and give an error at compile time. The
450        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
452    30. JIT compiler update.
454    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
455        Rill for the patch.
457    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
459    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
461    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
462        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
463        was enabled.
465    35. Improve JIT code generation for greedy plus quantifier.
467    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
468        1 to "aa" instead of to an empty string. The bug affected repeated groups
469        that could potentially match an empty string.
471    37. Optimizing single character iterators in JIT.
473    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
474        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
475        codepoints that are too big for the mode are faulted, and in a UTF mode,
476        disallowed codepoints are also faulted.
478    39. If PCRE was compiled with UTF support, in three places in the DFA
479        matcher there was code that should only have been obeyed in UTF mode, but
480        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
481        processing when bytes with values greater than 127 were present. In 16-bit
482        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
483        both cases the values are those that cannot be the first data item in a UTF
484        character. The three items that might have provoked this were recursions,
485        possessively repeated groups, and atomic groups.
487    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
488        and pcregrep, because some OS require shared objects to be explicitly
489        passed to ld, causing the link step to fail if they are not.
491    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
492        mode, patterns that started with \h* or \R* might be incorrectly matched.
495    Version 8.30 04-February-2012
496    -----------------------------
498    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
499        name is defined in ctype.h.
501    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
502        only in quite long subpatterns.
504    3.  Removed the function pcre_info(), which has been obsolete and deprecated
505        since it was replaced by pcre_fullinfo() in February 2000.
507    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
508        match a (*MARK), and the match failed at the start of the subject, a
509        reference to memory before the start of the subject could occur. This bug
510        was introduced by fix 17 of release 8.21.
512    5.  A reference to an unset group with zero minimum repetition was giving
513        totally wrong answers (in non-JavaScript-compatibility mode). For example,
514        /(another)?(\1?)test/ matched against "hello world test". This bug was
515        introduced in release 8.13.
517    6.  Add support for 16-bit character strings (a large amount of work involving
518        many changes and refactorings).
520    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
521        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
522        from a file.
524    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
525        rounding is not applied in this particular case).
527    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
528        if they appear, or are escaped, in patterns.
530    10. Get rid of a number of -Wunused-but-set-variable warnings.
532    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
533        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
534        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
535        also returns the mark "x". This bug applied to capturing parentheses,
536        non-capturing parentheses, and atomic parentheses. It also applied to some
537        assertions.
539    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
540        information out of configure.ac instead of relying on pcre.h.generic, which
541        is not stored in the repository.
543    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
544        -lreadline.
546    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
548    15. Applied Graycode's patch to put the top-level frame on the stack rather
549        than the heap when not using the stack for recursion. This gives a
550        performance improvement in many cases when recursion is not deep.
552    16. Experimental code added to "pcretest -C" to output the stack frame size.
555    Version 8.21 12-Dec-2011
556    ------------------------
558    1.  Updating the JIT compiler.
560    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
561        are added as well.
563    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
564        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
565        calling _pcre_jit_exec. Some extra comments are added.
567    4.  (*MARK) settings inside atomic groups that do not contain any capturing
568        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
569        was introduced by change 18 for 8.20.
571    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
572        ECMA-262 standard.
574    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
575        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
576        This bug was probably introduced by change 9 of 8.13.
578    7.  While fixing 6 above, I noticed that a number of other items were being
579        incorrectly rejected as "not fixed length". This arose partly because newer
580        opcodes had not been added to the fixed-length checking code. I have (a)
581        corrected the bug and added tests for these items, and (b) arranged for an
582        error to occur if an unknown opcode is encountered while checking for fixed
583        length instead of just assuming "not fixed length". The items that were
584        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
585        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
586        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
588    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
589        being incorrectly compiled and would have given unpredicatble results.
591    9.  A possessively repeated subpattern with minimum repeat count greater than
592        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
593        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
594        the first (A) could occur when it should not.
596    10. Add a cast and remove a redundant test from the code.
598    11. JIT should use pcre_malloc/pcre_free for allocation.
600    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
601        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
602        is anything other than /usr, -L is still shown).
604    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
606    14. Perl does not support \N without a following name in a [] class; PCRE now
607        also gives an error.
609    15. If a forward reference was repeated with an upper limit of around 2000,
610        it caused the error "internal error: overran compiling workspace". The
611        maximum number of forward references (including repeats) was limited by the
612        internal workspace, and dependent on the LINK_SIZE. The code has been
613        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
614        the default depends on LINK_SIZE. There is a new upper limit (for safety)
615        of around 200,000 forward references. While doing this, I also speeded up
616        the filling in of repeated forward references.
618    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
619        incorrectly expecting the subject to contain another "a" after the start.
621    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
622        in the match, the SKIP should be ignored. This was not happening; instead
623        the SKIP was being treated as NOMATCH. For patterns such as
624        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
625        tested.
627    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
628        now much more compatible with Perl, in particular in cases where the result
629        is a non-match for a non-anchored pattern. For example, if
630        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
631        "m", where previously it did not return a name. A side effect of this
632        change is that for partial matches, the last encountered mark name is
633        returned, as for non matches. A number of tests that were previously not
634        Perl-compatible have been moved into the Perl-compatible test files. The
635        refactoring has had the pleasing side effect of removing one argument from
636        the match() function, thus reducing its stack requirements.
638    19. If the /S+ option was used in pcretest to study a pattern using JIT,
639        subsequent uses of /S (without +) incorrectly behaved like /S+.
641    21. Retrieve executable code size support for the JIT compiler and fixing
642        some warnings.
644    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
645        not work when the shorter character appeared right at the end of the
646        subject string.
648    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
649        systems.
651    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
652        output it when the /M option is used in pcretest.
654    25. The CheckMan script was not being included in the distribution. Also, added
655        an explicit "perl" to run Perl scripts from the PrepareRelease script
656        because this is reportedly needed in Windows.
658    26. If study data was being save in a file and studying had not found a set of
659        "starts with" bytes for the pattern, the data written to the file (though
660        never used) was taken from uninitialized memory and so caused valgrind to
661        complain.
663    27. Updated RunTest.bat as provided by Sheri Pierce.
665    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
667    29. Computation of memory usage for the table of capturing group names was
668        giving an unnecessarily large value.
671    Version 8.20 21-Oct-2011
672    ------------------------
674    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
675        a POSIX class. After further experiments with Perl, which convinced me that
676        Perl has bugs and confusions, a closing square bracket is no longer allowed
677        in a POSIX name. This bug also affected patterns with classes that started
678        with full stops.
680    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
681        captured substring, but while checking the failing first alternative,
682        substring 1 is temporarily captured. If the output vector supplied to
683        pcre_exec() was not big enough for this capture, the yield of the function
684        was still zero ("insufficient space for captured substrings"). This cannot
685        be totally fixed without adding another stack variable, which seems a lot
686        of expense for a edge case. However, I have improved the situation in cases
687        such as /(a)(b)x|abc/ matched against "abc", where the return code
688        indicates that fewer than the maximum number of slots in the ovector have
689        been set.
691    3.  Related to (2) above: when there are more back references in a pattern than
692        slots in the output vector, pcre_exec() uses temporary memory during
693        matching, and copies in the captures as far as possible afterwards. It was
694        using the entire output vector, but this conflicts with the specification
695        that only 2/3 is used for passing back captured substrings. Now it uses
696        only the first 2/3, for compatibility. This is, of course, another edge
697        case.
699    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
700        main code base, and can be used by building with --enable-jit. When this is
701        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
702        runtime --no-jit option is given.
704    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
705        ovector, the return from the function was zero, implying that there were
706        other matches that did not fit. The correct "exactly full" value is now
707        returned.
709    6.  If a subpattern that was called recursively or as a subroutine contained
710        (*PRUNE) or any other control that caused it to give a non-standard return,
711        invalid errors such as "Error -26 (nested recursion at the same subject
712        position)" or even infinite loops could occur.
714    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
715        computing the minimum length on reaching *ACCEPT, and so ended up with the
716        wrong value of 1 rather than 0. Further investigation indicates that
717        computing a minimum subject length in the presence of *ACCEPT is difficult
718        (think back references, subroutine calls), and so I have changed the code
719        so that no minimum is registered for a pattern that contains *ACCEPT.
721    8.  If (*THEN) was present in the first (true) branch of a conditional group,
722        it was not handled as intended. [But see 16 below.]
724    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
725        Sheri Pierce.
727    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
728        the first byte in a match must be "a".
730    11. Change 17 for 8.13 increased the recursion depth for patterns like
731        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
732        pattern contains any instances of (*THEN). If it does not, the old
733        optimizations are restored. It would be nice to do this on a per-group
734        basis, but at the moment that is not feasible.
736    12. In some environments, the output of pcretest -C is CRLF terminated. This
737        broke RunTest's code that checks for the link size. A single white space
738        character after the value is now allowed for.
740    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
741        For "fr", it uses the Windows-specific input and output files.
743    14. If (*THEN) appeared in a group that was called recursively or as a
744        subroutine, it did not work as intended. [But see next item.]
746    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
747        pattern fragments (but not containing any | characters). If A and B are
748        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
749        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
750        D. In other words, Perl considers parentheses that do not contain any |
751        characters to be part of a surrounding alternative, whereas PCRE was
752        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
753        differently. PCRE now behaves in the same way as Perl, except in the case
754        of subroutine/recursion calls such as (?1) which have in any case always
755        been different (but PCRE had them first :-).
757    16. Related to 15 above: Perl does not treat the | in a conditional group as
758        creating alternatives. Such a group is treated in the same way as an
759        ordinary group without any | characters when processing (*THEN). PCRE has
760        been changed to match Perl's behaviour.
762    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
763        RunGrepTest script failed.
765    18. Change 22 for version 13 caused atomic groups to use more stack. This is
766        inevitable for groups that contain captures, but it can lead to a lot of
767        stack use in large patterns. The old behaviour has been restored for atomic
768        groups that do not contain any capturing parentheses.
770    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
771        suppress the check for a minimum subject length at run time. (If it was
772        given to pcre_exec() or pcre_dfa_exec() it did work.)
774    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
775        fail to work when decoding hex characters in data strings in EBCDIC
776        environments.
778    21. It appears that in at least one Mac OS environment, the isxdigit() function
779        is implemented as a macro that evaluates to its argument more than once,
780        contravening the C 90 Standard (I haven't checked a later standard). There
781        was an instance in pcretest which caused it to go wrong when processing
782        \x{...} escapes in subject strings. The has been rewritten to avoid using
783        things like p++ in the argument of isxdigit().
786    Version 8.13 16-Aug-2011
787    ------------------------
789    1.  The Unicode data tables have been updated to Unicode 6.0.0.
791    2.  Two minor typos in pcre_internal.h have been fixed.
793    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
794        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
795        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
797    4.  There were a number of related bugs in the code for matching backrefences
798        caselessly in UTF-8 mode when codes for the characters concerned were
799        different numbers of bytes. For example, U+023A and U+2C65 are an upper
800        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
801        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
802        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
803        2-byte code at the end of the subject (it thought there wasn't enough data
804        left).
806    5.  Comprehensive information about what went wrong is now returned by
807        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
808        as the output vector has at least 2 elements. The offset of the start of
809        the failing character and a reason code are placed in the vector.
811    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
812        now returned is for the first byte of the failing character, instead of the
813        last byte inspected. This is an incompatible change, but I hope it is small
814        enough not to be a problem. It makes the returned offset consistent with
815        pcre_exec() and pcre_dfa_exec().
817    7.  pcretest now gives a text phrase as well as the error number when
818        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
819        failure, the offset and reason code are output.
821    8.  When \R was used with a maximizing quantifier it failed to skip backwards
822        over a \r\n pair if the subsequent match failed. Instead, it just skipped
823        back over a single character (\n). This seems wrong (because it treated the
824        two characters as a single entity when going forwards), conflicts with the
825        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
826        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
827        has been changed.
829    9.  Some internal refactoring has changed the processing so that the handling
830        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
831        time (the PCRE_DOTALL option was changed this way some time ago: version
832        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
833        which was always a bit of a fudge. It also means that there is one less
834        argument for the match() function, which reduces its stack requirements
835        slightly. This change also fixes an incompatibility with Perl: the pattern
836        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
838    10. More internal refactoring has drastically reduced the number of recursive
839        calls to match() for possessively repeated groups such as (abc)++ when
840        using pcre_exec().
842    11. While implementing 10, a number of bugs in the handling of groups were
843        discovered and fixed:
845        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
846        (a|)*(?1) gave a compile-time internal error.
847        ((a|)+)+  did not notice that the outer group could match an empty string.
848        (^a|^)+   was not marked as anchored.
849        (.*a|.*)+ was not marked as matching at start or after a newline.
851    12. Yet more internal refactoring has removed another argument from the match()
852        function. Special calls to this function are now indicated by setting a
853        value in a variable in the "match data" data block.
855    13. Be more explicit in pcre_study() instead of relying on "default" for
856        opcodes that mean there is no starting character; this means that when new
857        ones are added and accidentally left out of pcre_study(), testing should
858        pick them up.
860    14. The -s option of pcretest has been documented for ages as being an old
861        synonym of -m (show memory usage). I have changed it to mean "force study
862        for every regex", that is, assume /S for every regex. This is similar to -i
863        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
864        using it. It makes it easier to run collections of tests with and without
865        study enabled, and thereby test pcre_study() more easily. All the standard
866        tests are now run with and without -s (but some patterns can be marked as
867        "never study" - see 20 below).
869    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
870        restoration of the capturing data to the outer values was not happening
871        correctly.
873    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
874        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
875        pattern had matched an empty string, and so incorrectly returned a no
876        match.
878    17. There was optimizing code for the last branch of non-capturing parentheses,
879        and also for the obeyed branch of a conditional subexpression, which used
880        tail recursion to cut down on stack usage. Unfortunately, now that there is
881        the possibility of (*THEN) occurring in these branches, tail recursion is
882        no longer possible because the return has to be checked for (*THEN). These
883        two optimizations have therefore been removed. [But see 8.20/11 above.]
885    18. If a pattern containing \R was studied, it was assumed that \R always
886        matched two bytes, thus causing the minimum subject length to be
887        incorrectly computed because \R can also match just one byte.
889    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
890        was incorrectly computed.
892    20. If /S is present twice on a test pattern in pcretest input, it now
893        *disables* studying, thereby overriding the use of -s on the command line
894        (see 14 above). This is necessary for one or two tests to keep the output
895        identical in both cases.
897    21. When (*ACCEPT) was used in an assertion that matched an empty string and
898        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
900    22. When an atomic group that contained a capturing parenthesis was
901        successfully matched, but the branch in which it appeared failed, the
902        capturing was not being forgotten if a higher numbered group was later
903        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
904        group 1 to "a", when in fact it should be unset. This applied to multi-
905        branched capturing and non-capturing groups, repeated or not, and also to
906        positive assertions (capturing in negative assertions does not happen
907        in PCRE) and also to nested atomic groups.
909    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
910        subject after a captured substring, to make it easier to tell which of a
911        number of identical substrings has been captured.
913    24. The way atomic groups are processed by pcre_exec() has been changed so that
914        if they are repeated, backtracking one repetition now resets captured
915        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
916        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
917        "aaa". Previously, it would have been "a". As part of this code
918        refactoring, the way recursive calls are handled has also been changed.
920    25. If an assertion condition captured any substrings, they were not passed
921        back unless some other capturing happened later. For example, if
922        (?(?=(a))a) was matched against "a", no capturing was returned.
924    26. When studying a pattern that contained subroutine calls or assertions,
925        the code for finding the minimum length of a possible match was handling
926        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
927        group 1 called group 2 while simultaneously a separate group 2 called group
928        1). A stack overflow occurred in this case. I have fixed this by limiting
929        the recursion depth to 10.
931    27. Updated RunTest.bat in the distribution to the version supplied by Tom
932        Fortmann. This supports explicit test numbers on the command line, and has
933        argument validation and error reporting.
935    28. An instance of \X with an unlimited repeat could fail if at any point the
936        first character it looked at was a mark character.
938    29. Some minor code refactoring concerning Unicode properties and scripts
939        should reduce the stack requirement of match() slightly.
941    30. Added the '=' option to pcretest to check the setting of unused capturing
942        slots at the end of the pattern, which are documented as being -1, but are
943        not included in the return count.
945    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
946        compiled something random. Now it gives a compile-time error (as does
947        Perl).
949    32. A *MARK encountered during the processing of a positive assertion is now
950        recorded and passed back (compatible with Perl).
952    33. If --only-matching or --colour was set on a pcregrep call whose pattern
953        had alternative anchored branches, the search for a second match in a line
954        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
955        matched the line "0102" twice. The same bug affected patterns that started
956        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
957        twice.
959    34. Previously, PCRE did not allow quantification of assertions. However, Perl
960        does, and because of capturing effects, quantifying parenthesized
961        assertions may at times be useful. Quantifiers are now allowed for
962        parenthesized assertions.
964    35. A minor code tidy in pcre_compile() when checking options for \R usage.
966    36. \g was being checked for fancy things in a character class, when it should
967        just be a literal "g".
969    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
970        appearance of a nested POSIX class supersedes an apparent external class.
971        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
972        unescaped square brackets may also appear as part of class names. For
973        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
974        more like Perl. (But see 8.20/1 above.)
976    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
977        was because it thought it was \N{name}, which is not supported).
979    39. Add minix to OS list not supporting the -S option in pcretest.
981    40. PCRE tries to detect cases of infinite recursion at compile time, but it
982        cannot analyze patterns in sufficient detail to catch mutual recursions
983        such as ((?1))((?2)). There is now a runtime test that gives an error if a
984        subgroup is called recursively as a subpattern for a second time at the
985        same position in the subject string. In previous releases this might have
986        been caught by the recursion limit, or it might have run out of stack.
988    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
989        happen only once. PCRE was, however incorrectly giving a compile time error
990        "recursive call could loop indefinitely" because it cannot analyze the
991        pattern in sufficient detail. The compile time test no longer happens when
992        PCRE is compiling a conditional subpattern, but actual runaway loops are
993        now caught at runtime (see 40 above).
995    42. It seems that Perl allows any characters other than a closing parenthesis
996        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
997        has been changed to be the same.
999    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1000        as not to get warnings when autogen.sh is called. Also changed
1001        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1003    44. To help people who use pcregrep to scan files containing exceedingly long
1004        lines, the following changes have been made:
1006        (a) The default value of the buffer size parameter has been increased from
1007            8K to 20K. (The actual buffer used is three times this size.)
1009        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1010            PCRE is built.
1012        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1013            to be set at run time.
1015        (d) Numerical values in pcregrep options can be followed by K or M, for
1016            example --buffer-size=50K.
1018        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1019            given and the return code is set to 2.
1021    45. Add a pointer to the latest mark to the callout data block.
1023    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1024        partial match of an empty string instead of no match. This was specific to
1025        the use of ".".
1027    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1028        complete match instead of a partial match. This bug was dependent on both
1029        the PCRE_UTF8 and PCRE_DOTALL options being set.
1031    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1032        starting byte set, because \b was not being ignored.
1035    Version 8.12 15-Jan-2011
1036    ------------------------
1038    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1039        checks for such things as part of the documentation building process.
1041    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1042        --match-limit and --recursion-limit options (added for 8.11). In
1043        particular, this made one of the standard tests fail. (The integer value
1044        went into the wrong half of a long int.)
1046    3.  If the --colour option was given to pcregrep with -v (invert match), it
1047        did strange things, either producing crazy output, or crashing. It should,
1048        of course, ignore a request for colour when reporting lines that do not
1049        match.
1051    4.  Another pcregrep bug caused similar problems if --colour was specified with
1052        -M (multiline) and the pattern match finished with a line ending.
1054    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1055        matched in multiline mode, the following line was shown as part of the
1056        match. This seems wrong, so I have changed it.
1058    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1059        the check for further matches in the same line (so they could be coloured)
1060        to overrun the end of the current line. If another match was found, it was
1061        incorrectly shown (and then shown again when found in the next line).
1063    7.  If pcregrep was compiled under Windows, there was a reference to the
1064        function pcregrep_exit() before it was defined. I am assuming this was
1065        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1066        reported by a user. I've moved the definition above the reference.
1069    Version 8.11 10-Dec-2010
1070    ------------------------
1072    1.  (*THEN) was not working properly if there were untried alternatives prior
1073        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1074        backtracked to try for "b" instead of moving to the next alternative branch
1075        at the same level (in this case, to look for "c"). The Perl documentation
1076        is clear that when (*THEN) is backtracked onto, it goes to the "next
1077        alternative in the innermost enclosing group".
1079    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1080        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1081        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1082        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1083        (*THEN).
1085    3.  If \s appeared in a character class, it removed the VT character from
1086        the class, even if it had been included by some previous item, for example
1087        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1088        of \s, but is part of the POSIX "space" class.)
1090    4.  A partial match never returns an empty string (because you can always
1091        match an empty string at the end of the subject); however the checking for
1092        an empty string was starting at the "start of match" point. This has been
1093        changed to the "earliest inspected character" point, because the returned
1094        data for a partial match starts at this character. This means that, for
1095        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1096        (previously it gave "no match").
1098    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1099        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1100        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1101        has an implication that the given string is incomplete (because a partial
1102        match is preferred over a full match). For this reason, these items now
1103        give a partial match in this situation. [Aside: previously, the one case
1104        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1105        match rather than a full match, which was wrong by the old rules, but is
1106        now correct.]
1108    6.  There was a bug in the handling of #-introduced comments, recognized when
1109        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1110        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1111        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1112        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1113        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1114        places in pcre_compile().
1116    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1117        comments when looking ahead for named forward references to subpatterns,
1118        the only newline sequence it recognized was NL. It now handles newlines
1119        according to the set newline convention.
1121    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1122        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1123        cater for a lack of strerror(). These oversights have been fixed.
1125    9.  Added --match-limit and --recursion-limit to pcregrep.
1127    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1129    11. When the -o option was used, pcregrep was setting a return code of 1, even
1130        when matches were found, and --line-buffered was not being honoured.
1132    12. Added an optional parentheses number to the -o and --only-matching options
1133        of pcregrep.
1135    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1136        can match an empty string. The code to do it in pcretest and pcredemo
1137        needed fixing:
1139        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1140            only one byte after an empty string match just before CRLF (this case
1141            just got forgotten; "any" and "anycrlf" were OK).
1143        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1144            mode when an empty string match preceded an ASCII character followed by
1145            a non-ASCII character. (The code for advancing by one character rather
1146            than one byte was nonsense.)
1148        (c) The pcredemo.c sample program did not have any code at all to handle
1149            the cases when CRLF is a valid newline sequence.
1151    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1152        as a starting offset was within the subject string. There is now a new
1153        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1154        negative or greater than the length of the string. In order to test this,
1155        pcretest is extended to allow the setting of negative starting offsets.
1157    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1158        starting offset points to the beginning of a UTF-8 character was
1159        unnecessarily clumsy. I tidied it up.
1161    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1162        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1164    17. Nobody had reported that the --include_dir option, which was added in
1165        release 7.7 should have been called --include-dir (hyphen, not underscore)
1166        for compatibility with GNU grep. I have changed it to --include-dir, but
1167        left --include_dir as an undocumented synonym, and the same for
1168        --exclude-dir, though that is not available in GNU grep, at least as of
1169        release 2.5.4.
1171    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1172        characters from a string of bytes) have been redefined so as not to use
1173        loops, in order to improve performance in some environments. At the same
1174        time, I abstracted some of the common code into auxiliary macros to save
1175        repetition (this should not affect the compiled code).
1177    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1178        compile-time error is now given if \c is not followed by an ASCII
1179        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1180        different, and any byte value is allowed.)
1182    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1183        START_OPTIMIZE option, which is now allowed at compile time - but just
1184        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1185        to pcregrep and other applications that have no direct access to PCRE
1186        options. The new /Y option in pcretest sets this option when calling
1187        pcre_compile().
1189    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1190        back references. Groups containing recursive back references were forced to
1191        be atomic by that change, but in the case of named groups, the amount of
1192        memory required was incorrectly computed, leading to "Failed: internal
1193        error: code overflow". This has been fixed.
1195    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1196        pcretest.c, to avoid build problems in some Borland environments.
1199    Version 8.10 25-Jun-2010
1200    ------------------------
1202    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1203        THEN.
1205    2.  (*ACCEPT) was not working when inside an atomic group.
1207    3.  Inside a character class, \B is treated as a literal by default, but
1208        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1209        causes the error). The code is unchanged, but I tidied the documentation.
1211    4.  Inside a character class, PCRE always treated \R and \X as literals,
1212        whereas Perl faults them if its -w option is set. I have changed PCRE so
1213        that it faults them when PCRE_EXTRA is set.
1215    5.  Added support for \N, which always matches any character other than
1216        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1218    6.  When compiling pcregrep with newer versions of gcc which may have
1219        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1220        declared with attribute warn_unused_result" were given. Just casting the
1221        result to (void) does not stop the warnings; a more elaborate fudge is
1222        needed. I've used a macro to implement this.
1224    7.  Minor change to pcretest.c to avoid a compiler warning.
1226    8.  Added four artifical Unicode properties to help with an option to make
1227        \s etc use properties (see next item). The new properties are: Xan
1228        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1230    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1231        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1232        this option. Modified pcretest to add /W to test this facility. Added
1233        REG_UCP to make it available via the POSIX interface.
1235    10. Added --line-buffered to pcregrep.
1237    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1238        studied, and the match started with a letter with a code point greater than
1239        127 whose first byte was different to the first byte of the other case of
1240        the letter, the other case of this starting letter was not recognized
1241        (#976).
1243    12. If a pattern that was studied started with a repeated Unicode property
1244        test, for example, \p{Nd}+, there was the theoretical possibility of
1245        setting up an incorrect bitmap of starting bytes, but fortunately it could
1246        not have actually happened in practice until change 8 above was made (it
1247        added property types that matched character-matching opcodes).
1249    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1250        possible starting bytes for non-anchored patterns.
1252    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1253        \R, and also a number of cases that involve Unicode properties, both
1254        explicit and implicit when PCRE_UCP is set.
1256    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1257        input, it could crash or give wrong results if characters with values
1258        greater than 0xc0 were present in the subject string. (Detail: it assumed
1259        UTF-8 input when processing these items.)
1261    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1262        size_t is 64-bit (#991).
1264    17. Added a check for running out of memory when PCRE is compiled with
1265        --disable-stack-for-recursion (#990).
1267    18. If the last data line in a file for pcretest does not have a newline on
1268        the end, a newline was missing in the output.
1270    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1271        less than 128) in its various bitmaps. However, there is a facility for
1272        generating tables according to the current locale when PCRE is compiled. It
1273        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1274        characters, are recognized by isspace() and therefore were getting set in
1275        these tables, and indeed these tables seem to approximate to ISO 8859. This
1276        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1277        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1278        which of course cannot start UTF-8 characters. I have changed the code so
1279        that only real ASCII characters (less than 128) and the correct starting
1280        bytes for UTF-8 encodings are set for characters greater than 127 when in
1281        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1282        altogether.)
1284    20. Added the /T option to pcretest so as to be able to run tests with non-
1285        standard character tables, thus making it possible to include the tests
1286        used for 19 above in the standard set of tests.
1288    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1289        reference to a subpattern the other side of a comment that contains an
1290        opening parenthesis caused either an internal compiling error, or a
1291        reference to the wrong subpattern.
1294    Version 8.02 19-Mar-2010
1295    ------------------------
1297    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1299    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1300        configured.
1302    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1303        original author of that file, following a query about its status.
1305    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1306        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1308    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1309        quantifier applied to a forward-referencing subroutine call, could compile
1310        incorrect code or give the error "internal error: previously-checked
1311        referenced subpattern not found".
1313    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1314        variables to point to external functions. For these systems, therefore,
1315        pcre_malloc etc. are now initialized to local functions that call the
1316        relevant global functions.
1318    7.  There were two entries missing in the vectors called coptable and poptable
1319        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1320        I've fixed the data, and added a kludgy way of testing at compile time that
1321        the lengths are correct (equal to the number of opcodes).
1323    8.  Following on from 7, I added a similar kludge to check the length of the
1324        eint vector in pcreposix.c.
1326    9.  Error texts for pcre_compile() are held as one long string to avoid too
1327        much relocation at load time. To find a text, the string is searched,
1328        counting zeros. There was no check for running off the end of the string,
1329        which could happen if a new error number was added without updating the
1330        string.
1332    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1334    11. \K was not working if it appeared in an atomic group or in a group that
1335        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1336        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1337        the assertion is positive, but not if it is negative.
1339    12. Change 11 fortuitously reduced the size of the stack frame used in the
1340        "match()" function of pcre_exec.c by one pointer. Forthcoming
1341        implementation of support for (*MARK) will need an extra pointer on the
1342        stack; I have reserved it now, so that the stack frame size does not
1343        decrease.
1345    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1346        item in branch that calls a recursion is a subroutine call - as in the
1347        second branch in the above example - was incorrectly given the compile-
1348        time error "recursive call could loop indefinitely" because pcre_compile()
1349        was not correctly checking the subroutine for matching a non-empty string.
1351    14. The checks for overrunning compiling workspace could trigger after an
1352        overrun had occurred. This is a "should never occur" error, but it can be
1353        triggered by pathological patterns such as hundreds of nested parentheses.
1354        The checks now trigger 100 bytes before the end of the workspace.
1356    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1359    Version 8.01 19-Jan-2010
1360    ------------------------
1362    1.  If a pattern contained a conditional subpattern with only one branch (in
1363        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1364        computed the wrong minimum data length (which is of course zero for such
1365        subpatterns). This could cause incorrect "no match" results.
1367    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1368        the pattern is reset in the first branch, pcre_compile() failed with
1369        "internal error: code overflow at offset...". This happened only when
1370        the reset was to the original external option setting. (An optimization
1371        abstracts leading options settings into an external setting, which was the
1372        cause of this.)
1374    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1375        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1376        assertion pattern did not match (meaning that the assertion was true), it
1377        was incorrectly treated as false if the SKIP had been reached during the
1378        matching. This also applied to assertions used as conditions.
1380    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1381        assertion subpattern, including such a pattern used as a condition,
1382        unpredictable results occurred, instead of the error return
1385    5.  The C++ GlobalReplace function was not working like Perl for the special
1386        situation when an empty string is matched. It now does the fancy magic
1387        stuff that is necessary.
1389    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1390        removed. (These were left over from very, very early versions of PCRE.)
1392    7.  Some cosmetic changes to the code to make life easier when compiling it
1393        as part of something else:
1395        (a) Change DEBUG to PCRE_DEBUG.
1397        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1398            called "current" as "current_branch", to prevent a collision with the
1399            Linux macro when compiled as a kernel module.
1401        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1402            prevent a collision with the Linux macro when compiled as a kernel
1403            module.
1405    8.  In pcre_compile() there are some checks for integer overflows that used to
1406        cast potentially large values to (double). This has been changed to that
1407        when building, a check for int64_t is made, and if it is found, it is used
1408        instead, thus avoiding the use of floating point arithmetic. (There is no
1409        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1410        double.
1412    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1413        2005 (difference between two addresses compared to an unsigned value).
1415    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1416        custom one, because of the following reported problem in Windows:
1418          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1419              under Win32.
1420          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1421              therefore missing the function definition.
1422          - The compiler thus generates a "C" signature for the test function.
1423          - The linker fails to find the "C" function.
1424          - PCRE fails to configure if asked to do so against libbz2.
1426    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1427        messages were output:
1429          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1430          rerunning libtoolize, to keep the correct libtool macros in-tree.
1431          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1433        I have done both of these things.
1435    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1436        most of the time, it *can* run out if it is given a pattern that contains a
1437        runaway infinite recursion. I updated the discussion in the pcrestack man
1438        page.
1440    13. Now that we have gone to the x.xx style of version numbers, the minor
1441        version may start with zero. Using 08 or 09 is a bad idea because users
1442        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1443        interpreted as invalid octal numbers. I've updated the previous comment in
1444        configure.ac, and also added a check that gives an error if 08 or 09 are
1445        used.
1447    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1448        causing partial matching to fail when the end of the subject matched \W
1449        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1451    15. There were some discrepancies between the declarations in pcre_internal.h
1452        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1453        their definitions. The declarations used "const uschar *" and the
1454        definitions used USPTR. Even though USPTR is normally defined as "const
1455        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1456        reported that: "This difference in casting confuses some C++ compilers, for
1457        example, SunCC recognizes above declarations as different functions and
1458        generates broken code for hbpcre." I have changed the declarations to use
1459        USPTR.
1461    16. GNU libtool is named differently on some systems. The autogen.sh script now
1462        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1463        (FreeBSD).
1465    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1466        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1467        comment: "Figure out how to create a longlong from a string: strtoll and
1468        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1469        instance, but it only takes 2 args instead of 3!"
1471    18. A subtle bug concerned with back references has been fixed by a change of
1472        specification, with a corresponding code fix. A pattern such as
1473        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1474        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1475        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1476        same bug. Such groups have to be quantified to be useful, or contained
1477        inside another quantified group. (If there's no repetition, the reference
1478        can never match.) The problem arises because, having left the group and
1479        moved on to the rest of the pattern, a later failure that backtracks into
1480        the group uses the captured value from the final iteration of the group
1481        rather than the correct earlier one. I have fixed this in PCRE by forcing
1482        any group that contains a reference to itself to be an atomic group; that
1483        is, there cannot be any backtracking into it once it has completed. This is
1484        similar to recursive and subroutine calls.
1487    Version 8.00 19-Oct-09
1488    ----------------------
1490    1.  The table for translating pcre_compile() error codes into POSIX error codes
1491        was out-of-date, and there was no check on the pcre_compile() error code
1492        being within the table. This could lead to an OK return being given in
1493        error.
1495    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1496        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1497        in a Windows environment.
1499    3.  The pcregrep --count option prints the count for each file even when it is
1500        zero, as does GNU grep. However, pcregrep was also printing all files when
1501        --files-with-matches was added. Now, when both options are given, it prints
1502        counts only for those files that have at least one match. (GNU grep just
1503        prints the file name in this circumstance, but including the count seems
1504        more useful - otherwise, why use --count?) Also ensured that the
1505        combination -clh just lists non-zero counts, with no names.
1507    4.  The long form of the pcregrep -F option was incorrectly implemented as
1508        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1509        but it seems right to fix it, and I didn't think it was worth preserving
1510        the old behaviour.
1512    5.  The command line items --regex=pattern and --regexp=pattern were not
1513        recognized by pcregrep, which required --regex pattern or --regexp pattern
1514        (with a space rather than an '='). The man page documented the '=' forms,
1515        which are compatible with GNU grep; these now work.
1517    6.  No libpcreposix.pc file was created for pkg-config; there was just
1518        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1520    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1521        when UCP support is not needed, by modifying the Python script that
1522        generates it from Unicode data files. This should not matter if the module
1523        is correctly used as a library, but I received one complaint about 50K of
1524        unwanted data. My guess is that the person linked everything into his
1525        program rather than using a library. Anyway, it does no harm.
1527    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1528        was a minimum greater than 1 for a wide character in a possessive
1529        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1530        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1531        character. Chaos in the form of incorrect output or a compiling loop could
1532        result.
1534    9.  The restrictions on what a pattern can contain when partial matching is
1535        requested for pcre_exec() have been removed. All patterns can now be
1536        partially matched by this function. In addition, if there are at least two
1537        slots in the offset vector, the offset of the earliest inspected character
1538        for the match and the offset of the end of the subject are set in them when
1539        PCRE_ERROR_PARTIAL is returned.
1541    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1542        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1543        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1544        and may be more useful for multi-segment matching.
1546    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1547        used to be given if ever the end of the subject was reached; now it is
1548        given only if matching could not proceed because another character was
1549        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1550        string "Z", which now yields "no match" instead of "partial match". In the
1551        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1552        final character ended with (*FAIL).
1554    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1555        if the pattern had a "must contain" character that was already found in the
1556        earlier partial match, unless partial matching was again requested. For
1557        example, with the pattern /dog.(body)?/, the "must contain" character is
1558        "g". If the first part-match was for the string "dog", restarting with
1559        "sbody" failed. This bug has been fixed.
1561    13. The string returned by pcre_dfa_exec() after a partial match has been
1562        changed so that it starts at the first inspected character rather than the
1563        first character of the match. This makes a difference only if the pattern
1564        starts with a lookbehind assertion or \b or \B (\K is not supported by
1565        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1566        matching functions compatible, and I think it's the right thing to do.
1568    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1569        so that the demonstration program is easily available in environments where
1570        PCRE has not been installed from source.
1572    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1573        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1574        library.
1576    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1577        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1578        is not the first non-POSIX option to be added. Clearly some people find
1579        these options useful.
1581    17. If a caller to the POSIX matching function regexec() passes a non-zero
1582        value for nmatch with a NULL value for pmatch, the value of
1583        nmatch is forced to zero.
1585    18. RunGrepTest did not have a test for the availability of the -u option of
1586        the diff command, as RunTest does. It now checks in the same way as
1587        RunTest, and also checks for the -b option.
1589    19. If an odd number of negated classes containing just a single character
1590        interposed, within parentheses, between a forward reference to a named
1591        subpattern and the definition of the subpattern, compilation crashed with
1592        an internal error, complaining that it could not find the referenced
1593        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1594        [The bug was that it was starting one character too far in when skipping
1595        over the character class, thus treating the ] as data rather than
1596        terminating the class. This meant it could skip too much.]
1598    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1599        /g option in pcretest when the pattern contains \K, which makes it possible
1600        to have an empty string match not at the start, even when the pattern is
1601        anchored. Updated pcretest and pcredemo to use this option.
1603    21. If the maximum number of capturing subpatterns in a recursion was greater
1604        than the maximum at the outer level, the higher number was returned, but
1605        with unset values at the outer level. The correct (outer level) value is
1606        now given.
1608    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1609        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1610        make it do so. The string so far is captured, making this feature
1611        compatible with Perl.
1613    23. The tests have been re-organized, adding tests 11 and 12, to make it
1614        possible to check the Perl 5.10 features against Perl 5.10.
1616    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1617        pattern matches a fixed length string. PCRE did not allow this; now it
1618        does. Neither allows recursion.
1620    25. I finally figured out how to implement a request to provide the minimum
1621        length of subject string that was needed in order to match a given pattern.
1622        (It was back references and recursion that I had previously got hung up
1623        on.) This code has now been added to pcre_study(); it finds a lower bound
1624        to the length of subject needed. It is not necessarily the greatest lower
1625        bound, but using it to avoid searching strings that are too short does give
1626        some useful speed-ups. The value is available to calling programs via
1627        pcre_fullinfo().
1629    26. While implementing 25, I discovered to my embarrassment that pcretest had
1630        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1631        study optimizations had never been tested with that matching function.
1632        Oops. What is worse, even when it was passed study data, there was a bug in
1633        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1634        were also very few tests of studied patterns with pcre_dfa_exec().
1636    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1637        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1638        on the other side of the coin, they are no longer allowed to have different
1639        names, because these cannot be distinguished in PCRE, and this has caused
1640        confusion. (This is a difference from Perl.)
1642    28. When duplicate subpattern names are present (necessarily with different
1643        numbers, as required by 27 above), and a test is made by name in a
1644        conditional pattern, either for a subpattern having been matched, or for
1645        recursion in such a pattern, all the associated numbered subpatterns are
1646        tested, and the overall condition is true if the condition is true for any
1647        one of them. This is the way Perl works, and is also more like the way
1648        testing by number works.
1651    Version 7.9 11-Apr-09
1652    ---------------------
1654    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1655        (pcretest), all targets were linked against these libraries. This included
1656        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1657        libraries. This caused unwanted dependencies to be created. This problem
1658        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1659        pcretest is linked with readline.
1661    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1662        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1663        moved outside it again, because FALSE and TRUE are already defined in AIX,
1664        but BOOL is not.
1666    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1667        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1669    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1670        hyphens) following file names and line numbers when outputting matching
1671        lines. This is not true; no spaces are inserted. I have also clarified the
1672        wording for the --colour (or --color) option.
1674    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1675        was not coloured; this is different to GNU grep, so I have changed it to be
1676        the same.
1678    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1679        each matching line was coloured. Now it goes on to look for further matches
1680        of any of the test patterns, which is the same behaviour as GNU grep.
1682    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1683        doesn't make sense to accept an empty string match in pcregrep, so I have
1684        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1685        seems to be how GNU grep behaves. [But see later change 40 for release
1686        8.33.]
1688    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1689        start or after a newline", because the conditional assertion was not being
1690        correctly handled. The rule now is that both the assertion and what follows
1691        in the first alternative must satisfy the test.
1693    9.  If auto-callout was enabled in a pattern with a conditional group whose
1694        condition was an assertion, PCRE could crash during matching, both with
1695        pcre_exec() and pcre_dfa_exec().
1697    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1698        used for matching.
1700    11. Unicode property support in character classes was not working for
1701        characters (bytes) greater than 127 when not in UTF-8 mode.
1703    12. Added the -M command line option to pcretest.
1705    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1707    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1709    16. Added comments and documentation about mis-use of no_arg in the C++
1710        wrapper.
1712    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1713        from Martin Jerabek that uses macro names for all relevant character and
1714        string constants.
1716    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1717        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1718        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1719        these, but not everybody uses configure.
1721    19. A conditional group that had only one branch was not being correctly
1722        recognized as an item that could match an empty string. This meant that an
1723        enclosing group might also not be so recognized, causing infinite looping
1724        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1725        with the subject "ab", where knowledge that the repeated group can match
1726        nothing is needed in order to break the loop.
1728    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1729        exec(), but without supplying a callout function, matching went wrong.
1731    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1732        leak if the size of the offset vector was greater than 30. When the vector
1733        is smaller, the saved offsets during recursion go onto a local stack
1734        vector, but for larger vectors malloc() is used. It was failing to free
1735        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1736        error, in fact).
1738    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1739        heapframe that is used only when UTF-8 support is enabled. This caused no
1740        problem, but was untidy.
1742    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1743        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1744        included within another project.
1746    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1747        slightly modified by me:
1749          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1750              not building pcregrep.
1752          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1753              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1755    25. Forward references, both numeric and by name, in patterns that made use of
1756        duplicate group numbers, could behave incorrectly or give incorrect errors,
1757        because when scanning forward to find the reference group, PCRE was not
1758        taking into account the duplicate group numbers. A pattern such as
1759        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1761    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1762        the feature of a custom pointer more persuasive (as requested by a user).
1764    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1765        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1766        pre-defined.
1768    28. Added support for (*UTF8) at the start of a pattern.
1770    29. Arrange for flags added by the "release type" setting in CMake to be shown
1771        in the configuration summary.
1774    Version 7.8 05-Sep-08
1775    ---------------------
1777    1.  Replaced UCP searching code with optimized version as implemented for Ad
1778        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1779        stage table and inline lookup instead of a function, giving speed ups of 2
1780        to 5 times on some simple patterns that I tested. Permission was given to
1781        distribute the MultiStage2.py script that generates the tables (it's not in
1782        the tarball, but is in the Subversion repository).
1784    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1785        scripts.
1787    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1788        a group with a zero qualifier. The result of the study could be incorrect,
1789        or the function might crash, depending on the pattern.
1791    4.  Caseless matching was not working for non-ASCII characters in back
1792        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1793        It now works when Unicode Property Support is available.
1795    5.  In pcretest, an escape such as \x{de} in the data was always generating
1796        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1797        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1798        truncation.
1800    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1802    7.  Added two (int) casts to pcregrep when printing the difference of two
1803        pointers, in case they are 64-bit values.
1805    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1806        test 2 if it fails.
1808    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1809        and a #define of that name to empty if it is not externally set. This is to
1810        allow users of MSVC to set it if necessary.
1812    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1813        the convenience functions in the pcre_get.c source file.
1815    11. An option change at the start of a pattern that had top-level alternatives
1816        could cause overwriting and/or a crash. This command provoked a crash in
1817        some environments:
1819          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1821        This potential security problem was recorded as CVE-2008-2371.
1823    12. For a pattern where the match had to start at the beginning or immediately
1824        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1825        pcre_dfa_exec() could read past the end of the passed subject if there was
1826        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1827        pcretest so that it places the subject at the end of its malloc-ed buffer.
1829    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1830        exec() might read past the end of the data buffer in UTF-8 mode.
1832    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1833        the data contained the byte 0x85 as part of a UTF-8 character within its
1834        first line. This applied both to normal and DFA matching.
1836    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1837        /^[^d]*?$/8 failed to match "abc".
1839    16. Added a missing copyright notice to pcrecpp_internal.h.
1841    17. Make it more clear in the documentation that values returned from
1842        pcre_exec() in ovector are byte offsets, not character counts.
1844    18. Tidied a few places to stop certain compilers from issuing warnings.
1846    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1847        supplied by Stefan Weber. I made a further small update for 7.8 because
1848        there is a change of source arrangements: the pcre_searchfuncs.c module is
1849        replaced by pcre_ucd.c.
1852    Version 7.7 07-May-08
1853    ---------------------
1855    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1856        a string to a long long, pretend we don't even have a long long." This is
1857        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1859    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1860        pre-7.6 versions, which defined a global no_arg variable instead of putting
1861        it in the RE class. (See also #8 below.)
1863    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1864        Lopes.
1866    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1868        (1) The include/exclude patterns were being applied to the whole pathnames
1869            of files, instead of just to the final components.
1871        (2) If there was more than one level of directory, the subdirectories were
1872            skipped unless they satisfied the include/exclude conditions. This is
1873            inconsistent with GNU grep (and could even be seen as contrary to the
1874            pcregrep specification - which I improved to make it absolutely clear).
1875            The action now is always to scan all levels of directory, and just
1876            apply the include/exclude patterns to regular files.
1878    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1879        --exclude_dir in the tests to avoid scanning .svn directories.
1881    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1882        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1883        doesn't support NULs in patterns.
1885    7.  Added some missing "const"s to declarations of static tables in
1886        pcre_compile.c and pcre_dfa_exec.c.
1888    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1889        caused by fix #2  above. (Subsequently also a second patch to fix the
1890        first patch. And a third patch - this was a messy problem.)
1892    9.  Applied Craig's patch to remove the use of push_back().
1894    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1895        matching function regexec().
1897    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1898        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1899        references. PCRE supports relative numbers with this syntax (I don't think
1900        Oniguruma does).
1902    12. Previously, a group with a zero repeat such as (...){0} was completely
1903        omitted from the compiled regex. However, this means that if the group
1904        was called as a subroutine from elsewhere in the pattern, things went wrong
1905        (an internal error was given). Such groups are now left in the compiled
1906        pattern, with a new opcode that causes them to be skipped at execution
1907        time.
1909    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1910        to the way PCRE behaves:
1912        (a) A lone ] character is dis-allowed (Perl treats it as data).
1914        (b) A back reference to an unmatched subpattern matches an empty string
1915            (Perl fails the current match path).
1917        (c) A data ] in a character class must be notated as \] because if the
1918            first data character in a class is ], it defines an empty class. (In
1919            Perl it is not possible to have an empty class.) The empty class []
1920            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1921            The negative empty class [^] matches any one character, independently
1922            of the DOTALL setting.
1924    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1925        non-existent subpattern following a character class starting with ']' and
1926        containing () gave an internal compiling error instead of "reference to
1927        non-existent subpattern". Fortunately, when the pattern did exist, the
1928        compiled code was correct. (When scanning forwards to check for the
1929        existence of the subpattern, it was treating the data ']' as terminating
1930        the class, so got the count wrong. When actually compiling, the reference
1931        was subsequently set up correctly.)
1933    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1934        it was being rejected as not supported by pcre_dfa_exec(), even though
1935        other assertions are supported. I have made pcre_dfa_exec() support
1936        (*FAIL).
1938    16. The implementation of 13c above involved the invention of a new opcode,
1939        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1940        cannot be changed at match time, I realized I could make a small
1941        improvement to matching performance by compiling OP_ALLANY instead of
1942        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1943        on the OP_ANY path.
1945    17. Compiling pcretest on Windows with readline support failed without the
1946        following two fixes: (1) Make the unistd.h include conditional on
1947        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1949    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1950        ncurses library to be included for pcretest when ReadLine support is
1951        requested, but also to allow for it to be overridden. This patch came from
1952        Daniel Bergström.
1954    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1955        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1956        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1957        spotting this.
1960    Version 7.6 28-Jan-08
1961    ---------------------
1963    1.  A character class containing a very large number of characters with
1964        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1965        overflow.
1967    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1968        HAVE_LONG_LONG is not defined.
1970    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1971        bring them up to date and include new features. This patch includes:
1973        - Fixed PH's badly added libz and libbz2 support.
1974        - Fixed a problem with static linking.
1975        - Added pcredemo. [But later removed - see 7 below.]
1976        - Fixed dftables problem and added an option.
1977        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1978            HAVE_LONG_LONG.
1979        - Added readline support for pcretest.
1980        - Added an listing of the option settings after cmake has run.
1982    4.  A user submitted a patch to Makefile that makes it easy to create
1983        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1984        Makefile.am that cause it to include this special target, without
1985        affecting anything else. Note that the same mingw target plus all
1986        the other distribution libraries and programs are now supported
1987        when configuring with CMake (see 6 below) instead of with
1988        Configure/Make.
1990    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1991        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1992        exported in the Windows port". It has not yet been confirmed that the patch
1993        solves the problem, but it does no harm.
1995    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1996        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1997        with CMake, and also correct the comment about stack recursion.
1999    7.  Remove the automatic building of pcredemo from the ./configure system and
2000        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
2001        of a program that users should build themselves after PCRE is installed, so
2002        building it automatically is not really right. What is more, it gave
2003        trouble in some build environments.
2005    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
2008    Version 7.5 10-Jan-08
2009    ---------------------
2011    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
2012        values in parens when parsing an RE using the C++ wrapper."
2014    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
2015        Characters greater than 255 were excluded from the class instead of being
2016        included.
2018    3.  The same bug as (2) above applied to negated POSIX classes such as
2019        [:^space:].
2021    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
2022        defined or documented. It seems to have been a typo for PCRE_STATIC, so
2023        I have changed it.
2025    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
2026        first named subpattern) and a construct such as (?&a) would reference the
2027        first named subpattern whose name started with "a" (in other words, the
2028        length check was missing). Both these problems are fixed. "Subpattern name
2029        expected" is now given for (?&) (a zero-length name), and this patch also
2030        makes it give the same error for \k'' (previously it complained that that
2031        was a reference to a non-existent subpattern).
2033    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
2034        this is right because (?- can be followed by option settings as well as by
2035        digits. I have, however, made the messages clearer.
2037    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
2038        than the number used in the conditional) now cause a compile-time error.
2039        This is actually not compatible with Perl, which accepts such patterns, but
2040        treats the conditional as always being FALSE (as PCRE used to), but it
2041        seems to me that giving a diagnostic is better.
2043    8.  Change "alphameric" to the more common word "alphanumeric" in comments
2044        and messages.
2046    9.  Fix two occurrences of "backslash" in comments that should have been
2047        "backspace".
2049    10. Remove two redundant lines of code that can never be obeyed (their function
2050        was moved elsewhere).
2052    11. The program that makes PCRE's Unicode character property table had a bug
2053        which caused it to generate incorrect table entries for sequences of
2054        characters that have the same character type, but are in different scripts.
2055        It amalgamated them into a single range, with the script of the first of
2056        them. In other words, some characters were in the wrong script. There were
2057        thirteen such cases, affecting characters in the following ranges:
2059          U+002b0 - U+002c1
2060          U+0060c - U+0060d
2061          U+0061e - U+00612
2062          U+0064b - U+0065e
2063          U+0074d - U+0076d
2064          U+01800 - U+01805
2065          U+01d00 - U+01d77
2066          U+01d9b - U+01dbf
2067          U+0200b - U+0200f
2068          U+030fc - U+030fe
2069          U+03260 - U+0327f
2070          U+0fb46 - U+0fbb1
2071          U+10450 - U+1049d
2073    12. The -o option (show only the matching part of a line) for pcregrep was not
2074        compatible with GNU grep in that, if there was more than one match in a
2075        line, it showed only the first of them. It now behaves in the same way as
2076        GNU grep.
2078    13. If the -o and -v options were combined for pcregrep, it printed a blank
2079        line for every non-matching line. GNU grep prints nothing, and pcregrep now
2080        does the same. The return code can be used to tell if there were any
2081        non-matching lines.
2083    14. Added --file-offsets and --line-offsets to pcregrep.
2085    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
2086        infinitely looping recursion. The bug was that positive lookaheads were not
2087        being skipped when checking for a possible empty match (negative lookaheads
2088        and both kinds of lookbehind were skipped).
2090    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
2091        inclusion of <windows.h> to before rather than after the definition of
2092        INVALID_FILE_ATTRIBUTES (patch from David Byron).
2094    17. Specifying a possessive quantifier with a specific limit for a Unicode
2095        character property caused pcre_compile() to compile bad code, which led at
2096        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
2097        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
2098        caused the error; without that there was no problem.
2100    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
2102    19. Added --enable-pcretest-libreadline.
2104    20. In pcrecpp.cc, the variable 'count' was incremented twice in
2105        RE::GlobalReplace(). As a result, the number of replacements returned was
2106        double what it should be. I removed one of the increments, but Craig sent a
2107        later patch that removed the other one (the right fix) and added unit tests
2108        that check the return values (which was not done before).
2110    21. Several CMake things:
2112        (1) Arranged that, when cmake is used on Unix, the libraries end up with
2113            the names libpcre and libpcreposix, not just pcre and pcreposix.
2115        (2) The above change means that pcretest and pcregrep are now correctly
2116            linked with the newly-built libraries, not previously installed ones.
2120    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
2121        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
2122        UTF-8 newline character). The key issue is that the pattern starts .*;
2123        this means that the match must be either at the beginning, or after a
2124        newline. The bug was in the code for advancing after a failed match and
2125        checking that the new position followed a newline. It was not taking
2126        account of UTF-8 characters correctly.
2128    23. PCRE was behaving differently from Perl in the way it recognized POSIX
2129        character classes. PCRE was not treating the sequence [:...:] as a
2130        character class unless the ... were all letters. Perl, however, seems to
2131        allow any characters between [: and :], though of course it rejects as
2132        unknown any "names" that contain non-letters, because all the known class
2133        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
2134        for example, whereas PCRE did not - it did not recognize a POSIX character
2135        class. This seemed a bit dangerous, so the code has been changed to be
2136        closer to Perl. The behaviour is not identical to Perl, because PCRE will
2137        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
2138        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
2139        Perl does, and where it didn't before.
2141    24. Rewrite so as to remove the single use of %n from pcregrep because in some
2142        Windows environments %n is disabled by default.
2145    Version 7.4 21-Sep-07
2146    ---------------------
2148    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
2149        means that a class such as [\s] counted as "explicit reference to CR or
2150        LF". That isn't really right - the whole point of the change was to try to
2151        help when there was an actual mention of one of the two characters. So now
2152        the change happens only if \r or \n (or a literal CR or LF) character is
2153        encountered.
2155    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
2156        of both had grown to the point where there were only 3 bits left.
2157        Fortunately, there was spare space in the data structure, and so I have
2158        moved the internal flags into a new 16-bit field to free up more option
2159        bits.
2161    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
2162        but did not set the internal JCHANGED flag - either of these is enough to
2163        control the way the "get" function works - but the PCRE_INFO_JCHANGED
2164        facility is supposed to tell if (?J) was ever used, so now (?J) at the
2165        start sets both bits.
2167    4.  Added options (at build time, compile time, exec time) to change \R from
2168        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
2170    5.  doc/pcresyntax.html was missing from the distribution.
2172    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
2173        compatibility, even though it is no longer used.
2175    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
2176        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
2177        windows.h file is present (where different names are used). [This was
2178        reversed later after testing - see 16 below.]
2180    8.  Changed all #include <config.h> to #include "config.h". There were also
2181        some further <pcre.h> cases that I changed to "pcre.h".
2183    9.  When pcregrep was used with the --colour option, it missed the line ending
2184        sequence off the lines that it output.
2186    10. It was pointed out to me that arrays of string pointers cause lots of
2187        relocations when a shared library is dynamically loaded. A technique of
2188        using a single long string with a table of offsets can drastically reduce
2189        these. I have refactored PCRE in four places to do this. The result is
2190        dramatic:
2192          Originally:                          290
2193          After changing UCP table:            187
2194          After changing error message table:   43
2195          After changing table of "verbs"       36
2196          After changing table of Posix names   22
2198        Thanks to the folks working on Gregex for glib for this insight.
2200    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
2201        unicode-properties was also set.
2203    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
2205    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
2206        checked only for CRLF.
2208    14. Added casts to pcretest.c to avoid compiler warnings.
2210    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
2212    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
2213        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
2214        entirely. This removes changes made in 7 above.
2216    17. The CMake files have been updated, and there is now more information about
2217        building with CMake in the NON-UNIX-USE document.
2220    Version 7.3 28-Aug-07
2221    ---------------------
2223     1. In the rejigging of the build system that eventually resulted in 7.1, the
2224        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
2225        brackets there is not right, since it causes compilers to look for an
2226        installed pcre.h, not the version that is in the source that is being
2227        compiled (which of course may be different). I have changed it back to:
2229          #include "pcre.h"
2231        I have a vague recollection that the change was concerned with compiling in
2232        different directories, but in the new build system, that is taken care of
2233        by the VPATH setting the Makefile.
2235     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
2236        when the subject happened to end in the byte 0x85 (e.g. if the last
2237        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
2238        characters but of course it shouldn't be taken as a newline when it is part
2239        of another character. The bug was that, for an unlimited repeat of . in
2240        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
2241        characters when looking for a newline.
2243     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
2245     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
2246        in debug output.
2248     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
2249        long printing in the pcrecpp unittest when running under MinGW.
2251     6. ESC_K was left out of the EBCDIC table.
2253     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
2254        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
2255        limit also applies to "virtual nesting" when a pattern is recursive, and in
2256        this case 1000 isn't so big. I have been able to remove this limit at the
2257        expense of backing off one optimization in certain circumstances. Normally,
2258        when pcre_exec() would call its internal match() function recursively and
2259        immediately return the result unconditionally, it uses a "tail recursion"
2260        feature to save stack. However, when a subpattern that can match an empty
2261        string has an unlimited repetition quantifier, it no longer makes this
2262        optimization. That gives it a stack frame in which to save the data for
2263        checking that an empty string has been matched. Previously this was taken
2264        from the 1000-entry workspace that had been reserved. So now there is no
2265        explicit limit, but more stack is used.
2267     8. Applied Daniel's patches to solve problems with the import/export magic
2268        syntax that is required for Windows, and which was going wrong for the
2269        pcreposix and pcrecpp parts of the library. These were overlooked when this
2270        problem was solved for the main library.
2272     9. There were some crude static tests to avoid integer overflow when computing
2273        the size of patterns that contain repeated groups with explicit upper
2274        limits. As the maximum quantifier is 65535, the maximum group length was
2275        set at 30,000 so that the product of these two numbers did not overflow a
2276        32-bit integer. However, it turns out that people want to use groups that
2277        are longer than 30,000 bytes (though not repeat them that many times).
2278        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
2279        made it possible to implement the integer overflow checks in a much more
2280        dynamic way, which I have now done. The artificial limitation on group
2281        length has been removed - we now have only the limit on the total length of
2282        the compiled pattern, which depends on the LINK_SIZE setting.
2284    10. Fixed a bug in the documentation for get/copy named substring when
2285        duplicate names are permitted. If none of the named substrings are set, the
2286        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
2287        empty string.
2289    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
2290        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
2291        because the ] is interpreted as the first data character and the
2292        terminating ] is not found. PCRE has been made compatible with Perl in this
2293        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
2294        cause memory overwriting.
2296    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
2297        string has been matched (to stop an infinite loop). It was not recognizing
2298        a conditional subpattern that could match an empty string if that
2299        subpattern was within another subpattern. For example, it looped when
2300        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
2301        condition was not nested. This bug has been fixed.
2303    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
2304        past the start of the subject in the presence of bytes with the top bit
2305        set, for example "\x8aBCD".
2307    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
2308        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
2310    14. Optimized (?!) to (*FAIL).
2312    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
2313        This restricts code points to be within the range 0 to 0x10FFFF, excluding
2314        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
2315        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
2316        does: it's just the validity check that is more restrictive.
2318    16. Inserted checks for integer overflows during escape sequence (backslash)
2319        processing, and also fixed erroneous offset values for syntax errors during
2320        backslash processing.
2322    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
2323        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
2325    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
2326        caused an overrun.
2328    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
2329        something other than just ASCII characters) inside a group that had an
2330        unlimited repeat caused a loop at compile time (while checking to see
2331        whether the group could match an empty string).
2333    20. Debugging a pattern containing \p or \P could cause a crash. For example,
2334        [\P{Any}] did so. (Error in the code for printing property names.)
2336    21. An orphan \E inside a character class could cause a crash.
2338    22. A repeated capturing bracket such as (A)? could cause a wild memory
2339        reference during compilation.
2341    23. There are several functions in pcre_compile() that scan along a compiled
2342        expression for various reasons (e.g. to see if it's fixed length for look
2343        behind). There were bugs in these functions when a repeated \p or \P was
2344        present in the pattern. These operators have additional parameters compared
2345        with \d, etc, and these were not being taken into account when moving along
2346        the compiled data. Specifically:
2348        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
2349            length.
2351        (b) An item such as \pL+ within a repeated group could cause crashes or
2352            loops.
2354        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
2355            "reference to non-existent subpattern" error.
2357        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
2359    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
2360        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
2362    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
2364    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
2365        character were causing crashes (broken optimization).
2367    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
2368        \p or \P) caused a compile-time loop.
2370    28. More problems have arisen in unanchored patterns when CRLF is a valid line
2371        break. For example, the unstudied pattern [\r\n]A does not match the string
2372        "\r\nA" because change 7.0/46 below moves the current point on by two
2373        characters after failing to match at the start. However, the pattern \nA
2374        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
2375        the same is true. There doesn't seem any very clean way out of this, but
2376        what I have chosen to do makes the common cases work: PCRE now takes note
2377        of whether there can be an explicit match for \r or \n anywhere in the
2378        pattern, and if so, 7.0/46 no longer applies. As part of this change,
2379        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
2380        pattern has explicit CR or LF references.
2382    29. Added (*CR) etc for changing newline setting at start of pattern.
2385    Version 7.2 19-Jun-07
2386    ---------------------
2388     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
2389        which is apparently normally available under Windows.
2391     2. Re-jig the pcregrep tests with different newline settings in an attempt
2392        to make them independent of the local environment's newline setting.
2394     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
2396     4. Some of the "internals" tests were previously cut out when the link size
2397        was not 2, because the output contained actual offsets. The recent new
2398        "Z" feature of pcretest means that these can be cut out, making the tests
2399        usable with all link sizes.
2401     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
2402        stack recursion. This gives a massive performance boost under BSD, but just
2403        a small improvement under Linux. However, it saves one field in the frame
2404        in all cases.
2406     6. Added more features from the forthcoming Perl 5.10:
2408        (a) (?-n) (where n is a string of digits) is a relative subroutine or
2409            recursion call. It refers to the nth most recently opened parentheses.
2411        (b) (?+n) is also a relative subroutine call; it refers to the nth next
2412            to be opened parentheses.
2414        (c) Conditions that refer to capturing parentheses can be specified
2415            relatively, for example, (?(-2)... or (?(+3)...
2417        (d) \K resets the start of the current match so that everything before
2418            is not part of it.
2420        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
2422        (f) \g{name} is another synonym - part of Perl 5.10's unification of
2423            reference syntax.
2425        (g) (?| introduces a group in which the numbering of parentheses in each
2426            alternative starts with the same number.
2428        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
2430     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
2433     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
2434        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
2435        for detecting groups that can match an empty string.
2437     9. A pattern with a very large number of alternatives (more than several
2438        hundred) was running out of internal workspace during the pre-compile
2439        phase, where pcre_compile() figures out how much memory will be needed. A
2440        bit of new cunning has reduced the workspace needed for groups with
2441        alternatives. The 1000-alternative test pattern now uses 12 bytes of
2442        workspace instead of running out of the 4096 that are available.
2444    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
2446    11. Applied patch from Google to remove an optimization that didn't quite work.
2447        The report of the bug said:
2449          pcrecpp::RE("a*").FullMatch("aaa") matches, while
2450          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
2451          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
2453    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
2454        it matched the wrong number of bytes.
2457    Version 7.1 24-Apr-07
2458    ---------------------
2460     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
2461        that is more "standard", making use of automake and other Autotools. There
2462        is some re-arrangement of the files and adjustment of comments consequent
2463        on this.
2465     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
2466        for recursive directory scanning broke on some systems because the files
2467        are not scanned in any specific order and on different systems the order
2468        was different. A call to "sort" has been inserted into RunGrepTest for the
2469        approprate test as a short-term fix. In the longer term there may be an
2470        alternative.
2472     3. I had an email from Eric Raymond about problems translating some of PCRE's
2473        man pages to HTML (despite the fact that I distribute HTML pages, some
2474        people do their own conversions for various reasons). The problems
2475        concerned the use of low-level troff macros .br and .in. I have therefore
2476        removed all such uses from the man pages (some were redundant, some could
2477        be replaced by .nf/.fi pairs). The 132html script that I use to generate
2478        HTML has been updated to handle .nf/.fi and to complain if it encounters
2479        .br or .in.
2481     4. Updated comments in configure.ac that get placed in config.h.in and also
2482        arranged for config.h to be included in the distribution, with the name
2483        config.h.generic, for the benefit of those who have to compile without
2484        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
2486     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
2487        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
2488        makevp.bat for the current PCRE, using the additional files
2489        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
2491     6. A Windows user reported a minor discrepancy with test 2, which turned out
2492        to be caused by a trailing space on an input line that had got lost in his
2493        copy. The trailing space was an accident, so I've just removed it.
2495     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
2496        that is needed.
2498     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
2499        as "const" (a) because they are and (b) because it helps the PHP
2500        maintainers who have recently made a script to detect big data structures
2501        in the php code that should be moved to the .rodata section. I remembered
2502        to update Builducptable as well, so it won't revert if ucptable.h is ever
2503        re-created.
2505     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
2506        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
2507        order to be able to cut out the UTF-8 tables in the latter when UTF-8
2508        support is not required. This saves 1.5-2K of code, which is important in
2509        some applications.
2511        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
2512        so as not to refer to the tables, even though these functions will never be
2513        called when UTF-8 support is disabled. Otherwise there are problems with a
2514        shared library.
2516    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
2518        (a) It was defining its arguments as char * instead of void *.
2520        (b) It was assuming that all moves were upwards in memory; this was true
2521            a long time ago when I wrote it, but is no longer the case.
2523        The emulated memove() is provided for those environments that have neither
2524        memmove() nor bcopy(). I didn't think anyone used it these days, but that
2525        is clearly not the case, as these two bugs were recently reported.
2527    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
2528        and Detrail to create the HTML documentation, the .txt form of the man
2529        pages, and it removes trailing spaces from listed files. It also creates
2530        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
2531        case, it wraps all the #defines with #ifndefs. This script should be run
2532        before "make dist".
2534    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
2535        with Unicode property support.
2537        (a) For a maximizing quantifier, if the two different cases of the
2538            character were of different lengths in their UTF-8 codings (there are
2539            some cases like this - I found 11), and the matching function had to
2540            back up over a mixture of the two cases, it incorrectly assumed they
2541            were both the same length.
2543        (b) When PCRE was configured to use the heap rather than the stack for
2544            recursion during matching, it was not correctly preserving the data for
2545            the other case of a UTF-8 character when checking ahead for a match
2546            while processing a minimizing repeat. If the check also involved
2547            matching a wide character, but failed, corruption could cause an
2548            erroneous result when trying to check for a repeat of the original
2549            character.
2551    13. Some tidying changes to the testing mechanism:
2553        (a) The RunTest script now detects the internal link size and whether there
2554            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
2555            values substituted by "configure". (The RunGrepTest script already did
2556            this for UTF-8.) The configure.ac script no longer substitutes the
2557            relevant variables.
2559        (b) The debugging options /B and /D in pcretest show the compiled bytecode
2560            with length and offset values. This means that the output is different
2561            for different internal link sizes. Test 2 is skipped for link sizes
2562            other than 2 because of this, bypassing the problem. Unfortunately,
2563            there was also a test in test 3 (the locale tests) that used /B and
2564            failed for link sizes other than 2. Rather than cut the whole test out,
2565            I have added a new /Z option to pcretest that replaces the length and
2566            offset values with spaces. This is now used to make test 3 independent
2567            of link size. (Test 2 will be tidied up later.)
2569    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2570        segmentation fault instead of returning the appropriate error message.
2572    15. In multiline mode when the newline sequence was set to "any", the pattern
2573        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2574        This doesn't seem right; it now treats the CRLF combination as the line
2575        ending, and so does not match in that case. It's only a pattern such as ^$
2576        that would hit this one: something like ^ABC$ would have failed after \r
2577        and then tried again after \r\n.
2579    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2580        in an attempt to make files that differ only in their line terminators
2581        compare equal. This works on Linux.
2583    17. Under certain error circumstances pcregrep might try to free random memory
2584        as it exited. This is now fixed, thanks to valgrind.
2586    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2587        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2588        was because its rules for how to advance for /g after matching an empty
2589        string at the end of a line did not allow for this case. They now check for
2590        it specially.
2592    20. pcretest is supposed to handle patterns and data of any length, by
2593        extending its buffers when necessary. It was getting this wrong when the
2594        buffer for a data line had to be extended.
2596    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2597        CRLF as a newline sequence.
2599    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2600        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2601        I have nevertheless tidied it up.
2603    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2605    24. Added a man page for pcre-config.
2608    Version 7.0 19-Dec-06
2609    ---------------------
2611     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2612        moving to gcc 4.1.1.
2614     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2615        sys/time.h, which is documented as needed for this function. It doesn't
2616        seem to matter on Linux, but it showed up on some releases of OS X.
2618     3. It seems that there are systems where bytes whose values are greater than
2619        127 match isprint() in the "C" locale. The "C" locale should be the
2620        default when a C program starts up. In most systems, only ASCII printing
2621        characters match isprint(). This difference caused the output from pcretest
2622        to vary, making some of the tests fail. I have changed pcretest so that:
2624        (a) When it is outputting text in the compiled version of a pattern, bytes
2625            other than 32-126 are always shown as hex escapes.
2627        (b) When it is outputting text that is a matched part of a subject string,
2628            it does the same, unless a different locale has been set for the match
2629            (using the /L modifier). In this case, it uses isprint() to decide.
2631     4. Fixed a major bug that caused incorrect computation of the amount of memory
2632        required for a compiled pattern when options that changed within the
2633        pattern affected the logic of the preliminary scan that determines the
2634        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2635        that the computed length was too small. The symptoms of this bug were
2636        either the PCRE error "internal error: code overflow" from pcre_compile(),
2637        or a glibc crash with a message such as "pcretest: free(): invalid next
2638        size (fast)". Examples of patterns that provoked this bug (shown in
2639        pcretest format) are:
2641          /(?-x: )/x
2642          /(?x)(?-x: \s*#\s*)/
2643          /((?i)[\x{c0}])/8
2644          /(?i:[\x{c0}])/8
2646        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2647        is now done differently.
2649     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2650        wrapper classes; (b) implement a new function in the C++ scanner that is
2651        more efficient than the old way of doing things because it avoids levels of
2652        recursion in the regex matching; (c) add a paragraph to the documentation
2653        for the FullMatch() function.
2655     6. The escape sequence \n was being treated as whatever was defined as
2656        "newline". Not only was this contrary to the documentation, which states
2657        that \n is character 10 (hex 0A), but it also went horribly wrong when
2658        "newline" was defined as CRLF. This has been fixed.
2660     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2661        was being set to -1 for the "end of line" case (supposedly a value that no
2662        character can have). Though this value is never used (the check for end of
2663        line is "zero bytes in current character"), it caused compiler complaints.
2664        I've changed it to 0xffffffff.
2666     8. In pcre_version.c, the version string was being built by a sequence of
2667        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2668        string (as it is for production releases) called a macro with an empty
2669        argument. The C standard says the result of this is undefined. The gcc
2670        compiler treats it as an empty string (which was what was wanted) but it is
2671        reported that Visual C gives an error. The source has been hacked around to
2672        avoid this problem.
2674     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2675        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2676        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2677        of them did).
2679    10. Originally, pcretest opened its input and output without "b"; then I was
2680        told that "b" was needed in some environments, so it was added for release
2681        5.0 to both the input and output. (It makes no difference on Unix-like
2682        systems.) Later I was told that it is wrong for the input on Windows. I've
2683        now abstracted the modes into two macros, to make it easier to fiddle with
2684        them, and removed "b" from the input mode under Windows.
2686    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2688    12. Added -help and --help to pcretest as an official way of being reminded
2689        of the options.
2691    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2692        and pcrecpp.cc because they annoy compilers at high warning levels.
2694    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2696    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2697        scripts are not C programs :-) and which was not noticed because it works
2698        on Linux.
2700    16. pcretest is supposed to handle any length of pattern and data line (as one
2701        line or as a continued sequence of lines) by extending its input buffer if
2702        necessary. This feature was broken for very long pattern lines, leading to
2703        a string of junk being passed to pcre_compile() if the pattern was longer
2704        than about 50K.
2706    17. I have done a major re-factoring of the way pcre_compile() computes the
2707        amount of memory needed for a compiled pattern. Previously, there was code
2708        that made a preliminary scan of the pattern in order to do this. That was
2709        OK when PCRE was new, but as the facilities have expanded, it has become
2710        harder and harder to keep it in step with the real compile phase, and there
2711        have been a number of bugs (see for example, 4 above). I have now found a
2712        cunning way of running the real compile function in a "fake" mode that
2713        enables it to compute how much memory it would need, while actually only
2714        ever using a few hundred bytes of working memory and without too many
2715        tests of the mode. This should make future maintenance and development
2716        easier. A side effect of this work is that the limit of 200 on the nesting
2717        depth of parentheses has been removed (though this was never a serious
2718        limitation, I suspect). However, there is a downside: pcre_compile() now
2719        runs more slowly than before (30% or more, depending on the pattern). I
2720        hope this isn't a big issue. There is no effect on runtime performance.
2722    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2723        newline (only possible for the last line of a file) and it was a
2724        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2726    19. Added additional timing features to pcretest. (1) The -tm option now times
2727        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2728        separate command line item, by a number that specifies the number of
2729        repeats to use when timing. The default is 50000; this gives better
2730        precision, but takes uncomfortably long for very large patterns.
2732    20. Extended pcre_study() to be more clever in cases where a branch of a
2733        subpattern has no definite first character. For example, (a*|b*)[cd] would
2734        previously give no result from pcre_study(). Now it recognizes that the
2735        first character must be a, b, c, or d.
2737    21. There was an incorrect error "recursive call could loop indefinitely" if
2738        a subpattern (or the entire pattern) that was being tested for matching an
2739        empty string contained only one non-empty item after a nested subpattern.
2740        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2741        incorrectly, because the \d was being skipped in the check.
2743    22. The pcretest program now has a new pattern option /B and a command line
2744        option -b, which is equivalent to adding /B to every pattern. This causes
2745        it to show the compiled bytecode, without the additional information that
2746        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2747        is the same as /B/I).
2749    23. A new optimization is now able automatically to treat some sequences such
2750        as a*b as a*+b. More specifically, if something simple (such as a character
2751        or a simple class like \d) has an unlimited quantifier, and is followed by
2752        something that cannot possibly match the quantified thing, the quantifier
2753        is automatically "possessified".
2755    24. A recursive reference to a subpattern whose number was greater than 39
2756        went wrong under certain circumstances in UTF-8 mode. This bug could also
2757        have affected the operation of pcre_study().
2759    25. Realized that a little bit of performance could be had by replacing
2760        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2762    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2764    27. Possessive quantifiers such as a++ were previously implemented by turning
2765        them into atomic groups such as ($>a+). Now they have their own opcodes,
2766        which improves performance. This includes the automatically created ones
2767        from 23 above.
2769    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2770        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2771        the first matched character to be a colon. This applied both to named and
2772        numbered groups.
2774    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2776    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2777        building PCRE on Windows easier, so I have included it in the distribution.
2779    31. There is now a check in pcretest against a ridiculously large number being
2780        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2781        loop, the loop is abandoned.
2783    32. Forward references to subpatterns in conditions such as (?(2)...) where
2784        subpattern 2 is defined later cause pcre_compile() to search forwards in
2785        the pattern for the relevant set of parentheses. This search went wrong
2786        when there were unescaped parentheses in a character class, parentheses
2787        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2789    33. "Subroutine" calls and backreferences were previously restricted to
2790        referencing subpatterns earlier in the regex. This restriction has now
2791        been removed.
2793    34. Added a number of extra features that are going to be in Perl 5.10. On the
2794        whole, these are just syntactic alternatives for features that PCRE had
2795        previously implemented using the Python syntax or my own invention. The
2796        other formats are all retained for compatibility.
2798        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2799            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2800            also .NET compatible.
2802        (b) A recursion or subroutine call to a named group can now be defined as
2803            (?&name) as well as (?P>name).
2805        (c) A backreference to a named group can now be defined as \k<name> or
2806            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2807            5.10, are also .NET compatible.
2809        (d) A conditional reference to a named group can now use the syntax
2810            (?(<name>) or (?('name') as well as (?(name).
2812        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2813            groups (named and numbered) that are never evaluated inline, but can be
2814            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2815            is always false. There may be only one alternative in such a group.
2817        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2818            as the simple (?(R). The condition is true only if the most recent
2819            recursion is that of the given number or name. It does not search out
2820            through the entire recursion stack.
2822        (g) The escape \gN or \g{N} has been added, where N is a positive or
2823            negative number, specifying an absolute or relative reference.
2825    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2826        some "unreachable code" warnings.
2828    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2829        things, this adds five new scripts.
2831    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2832        There were also incompatibilities regarding the handling of \Q..\E inside
2833        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2834        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2836    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2837        matches an empty string, and forcibly breaks the loop. There were bugs in
2838        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2839        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2840        separate and independent bugs (that affected different cases) have been
2841        fixed.
2843    39. Refactored the code to abolish the use of different opcodes for small
2844        capturing bracket numbers. This is a tidy that I avoided doing when I
2845        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2846        The new approach is not only tidier, it makes it possible to reduce the
2847        memory needed to fix the previous bug (38).
2849    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2850        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2851        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2852        mode.
2854    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2855        report.
2857    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2858        copy construction and assignment in the C++ wrapper.
2860    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2861        couple of bugs that could have given wrong results in the "--newline=crlf"
2862        case.
2864    44. Added a number of casts and did some reorganization of signed/unsigned int
2865        variables following suggestions from Dair Grant. Also renamed the variable
2866        "this" as "item" because it is a C++ keyword.
2868    45. Arranged for dftables to add
2870          #include "pcre_internal.h"
2872        to pcre_chartables.c because without it, gcc 4.x may remove the array
2873        definition from the final binary if PCRE is built into a static library and
2874        dead code stripping is activated.
2876    46. For an unanchored pattern, if a match attempt fails at the start of a
2877        newline sequence, and the newline setting is CRLF or ANY, and the next two
2878        characters are CRLF, advance by two characters instead of one.
2881    Version 6.7 04-Jul-06
2882    ---------------------
2884     1. In order to handle tests when input lines are enormously long, pcretest has
2885        been re-factored so that it automatically extends its buffers when
2886        necessary. The code is crude, but this _is_ just a test program. The
2887        default size has been increased from 32K to 50K.
2889     2. The code in pcre_study() was using the value of the re argument before
2890        testing it for NULL. (Of course, in any sensible call of the function, it
2891        won't be NULL.)
2893     3. The memmove() emulation function in pcre_internal.h, which is used on
2894        systems that lack both memmove() and bcopy() - that is, hardly ever -
2895        was missing a "static" storage class specifier.
2897     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2898        containing an extended class (one that cannot be represented by a bitmap
2899        because it contains high-valued characters or Unicode property items, e.g.
2900        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2901        pattern, but PCRE should not loop if you do not (it no longer does).
2902        [Detail: two cases were found: (a) a repeated subpattern containing an
2903        extended class; (b) a recursive reference to a subpattern that followed a
2904        previous extended class. It wasn't skipping over the extended class
2905        correctly when UTF-8 mode was not set.]
2907     5. A negated single-character class was not being recognized as fixed-length
2908        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2909        compile error "lookbehind assertion is not fixed length".
2911     6. The RunPerlTest auxiliary script was showing an unexpected difference
2912        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2913        write a Perl script that can interpret lines of an input file either as
2914        byte characters or as UTF-8, which is what "perltest" was being required to
2915        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2916        can't do is switch easily at run time between having the "use utf8;" pragma
2917        or not. In the end, I fudged it by using the RunPerlTest script to insert
2918        "use utf8;" explicitly for the UTF-8 tests.
2920     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2921        the end of the subject string, contrary to the documentation and to what
2922        Perl does. This was true of both matching functions. Now it matches only at
2923        the start of the subject and immediately after *internal* newlines.
2925     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2926        a pointer to an int instead of a pointer to an unsigned long int. This
2927        caused problems on 64-bit systems.
2929     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2930        instance of the 'standard' template library not being so standard".
2932    10. There was no check on the number of named subpatterns nor the maximum
2933        length of a subpattern name. The product of these values is used to compute
2934        the size of the memory block for a compiled pattern. By supplying a very
2935        long subpattern name and a large number of named subpatterns, the size
2936        computation could be caused to overflow. This is now prevented by limiting
2937        the length of names to 32 characters, and the number of named subpatterns
2938        to 10,000.
2940    11. Subpatterns that are repeated with specific counts have to be replicated in
2941        the compiled pattern. The size of memory for this was computed from the
2942        length of the subpattern and the repeat count. The latter is limited to
2943        65535, but there was no limit on the former, meaning that integer overflow
2944        could in principle occur. The compiled length of a repeated subpattern is
2945        now limited to 30,000 bytes in order to prevent this.
2947    12. Added the optional facility to have named substrings with the same name.
2949    13. Added the ability to use a named substring as a condition, using the
2950        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2951        are numbers (not recommended). Forward references are permitted.
2953    14. Added forward references in named backreferences (if you see what I mean).
2955    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2956        pattern could run off the end of the subject. For example, the pattern
2957        "(?s)(.{1,5})"8 did this with the subject "ab".
2959    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2960        PCRE_CASELESS was set when matching characters that were quantified with ?
2961        or *.
2963    17. A character class other than a single negated character that had a minimum
2964        but no maximum quantifier - for example [ab]{6,} - was not handled
2965        correctly by pce_dfa_exec(). It would match only one character.
2967    18. A valid (though odd) pattern that looked like a POSIX character
2968        class but used an invalid character after [ (for example [[,abc,]]) caused
2969        pcre_compile() to give the error "Failed: internal error: code overflow" or
2970        in some cases to crash with a glibc free() error. This could even happen if
2971        the pattern terminated after [[ but there just happened to be a sequence of
2972        letters, a binary zero, and a closing ] in the memory that followed.
2974    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2975        over the years. Originally (before any Unicode support), just the bottom 8
2976        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2977        output from "man perlunicode" includes this:
2979          The regular expression compiler produces polymorphic opcodes.  That
2980          is, the pattern adapts to the data and automatically switches to
2981          the Unicode character scheme when presented with Unicode data--or
2982          instead uses a traditional byte scheme when presented with byte
2983          data.
2985        Sadly, a wide octal escape does not cause a switch, and in a string with
2986        no other multibyte characters, these octal escapes are treated as before.
2987        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2988        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2989        Unicode string.
2991        I have not perpetrated such confusion in PCRE. Up till now, it took just
2992        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2993        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2994        translate to the appropriate multibyte character.
2996    29. Applied some refactoring to reduce the number of warnings from Microsoft
2997        and Borland compilers. This has included removing the fudge introduced
2998        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2999        a warning about an unused variable.
3001    21. PCRE has not included VT (character 0x0b) in the set of whitespace
3002        characters since release 4.0, because Perl (from release 5.004) does not.
3003        [Or at least, is documented not to: some releases seem to be in conflict
3004        with the documentation.] However, when a pattern was studied with
3005        pcre_study() and all its branches started with \s, PCRE still included VT
3006        as a possible starting character. Of course, this did no harm; it just
3007        caused an unnecessary match attempt.
3009    22. Removed a now-redundant internal flag bit that recorded the fact that case
3010        dependency changed within the pattern. This was once needed for "required
3011        byte" processing, but is no longer used. This recovers a now-scarce options
3012        bit. Also moved the least significant internal flag bit to the most-
3013        significant bit of the word, which was not previously used (hangover from
3014        the days when it was an int rather than a uint) to free up another bit for
3015        the future.
3017    23. Added support for CRLF line endings as well as CR and LF. As well as the
3018        default being selectable at build time, it can now be changed at runtime
3019        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
3020        specify that it is scanning data with non-default line endings.
3022    24. Changed the definition of CXXLINK to make it agree with the definition of
3023        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
3025    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
3026        recursions. This makes a big different to stack usage for some patterns.
3028    26. If a subpattern containing a named recursion or subroutine reference such
3029        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
3030        the space required for the compiled pattern went wrong and gave too small a
3031        value. Depending on the environment, this could lead to "Failed: internal
3032        error: code overflow at offset 49" or "glibc detected double free or
3033        corruption" errors.
3035    27. Applied patches from Google (a) to support the new newline modes and (b) to
3036        advance over multibyte UTF-8 characters in GlobalReplace.
3038    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
3039        difference for some implementation of PCRE in some Windows version.
3041    29. Added some extra testing facilities to pcretest:
3043        \q<number>   in a data line sets the "match limit" value
3044        \Q<number>   in a data line sets the "match recursion limt" value
3045        -S <number>  sets the stack size, where <number> is in megabytes
3047        The -S option isn't available for Windows.
3050    Version 6.6 06-Feb-06
3051    ---------------------
3053     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
3054        in pcreposix.h. I have copied the definition from pcre.h.
3056     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
3057        because pcre.h is no longer a built file.
3059     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
3060        not normally included in the compiled code.
3063    Version 6.5 01-Feb-06
3064    ---------------------
3066     1. When using the partial match feature with pcre_dfa_exec(), it was not
3067        anchoring the second and subsequent partial matches at the new starting
3068        point. This could lead to incorrect results. For example, with the pattern
3069        /1234/, partially matching against "123" and then "a4" gave a match.
3071     2. Changes to pcregrep:
3073        (a) All non-match returns from pcre_exec() were being treated as failures
3074            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
3075            error message is output. Some extra information is given for the
3076            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
3077            probably the only errors that are likely to be caused by users (by
3078            specifying a regex that has nested indefinite repeats, for instance).
3079            If there are more than 20 of these errors, pcregrep is abandoned.
3081        (b) A binary zero was treated as data while matching, but terminated the
3082            output line if it was written out. This has been fixed: binary zeroes
3083            are now no different to any other data bytes.
3085        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
3086            used to set a locale for matching. The --locale=xxxx long option has
3087            been added (no short equivalent) to specify a locale explicitly on the
3088            pcregrep command, overriding the environment variables.
3090        (d) When -B was used with -n, some line numbers in the output were one less
3091            than they should have been.
3093        (e) Added the -o (--only-matching) option.
3095        (f) If -A or -C was used with -c (count only), some lines of context were
3096            accidentally printed for the final match.
3098        (g) Added the -H (--with-filename) option.
3100        (h) The combination of options -rh failed to suppress file names for files
3101            that were found from directory arguments.
3103        (i) Added the -D (--devices) and -d (--directories) options.
3105        (j) Added the -F (--fixed-strings) option.
3107        (k) Allow "-" to be used as a file name for -f as well as for a data file.
3109        (l) Added the --colo(u)r option.
3111        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
3112            is not present by default.
3114     3. A nasty bug was discovered in the handling of recursive patterns, that is,
3115        items such as (?R) or (?1), when the recursion could match a number of
3116        alternatives. If it matched one of the alternatives, but subsequently,
3117        outside the recursion, there was a failure, the code tried to back up into
3118        the recursion. However, because of the way PCRE is implemented, this is not
3119        possible, and the result was an incorrect result from the match.
3121        In order to prevent this happening, the specification of recursion has
3122        been changed so that all such subpatterns are automatically treated as
3123        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
3125     4. I had overlooked the fact that, in some locales, there are characters for
3126        which isalpha() is true but neither isupper() nor islower() are true. In
3127        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
3128        and ordfeminine) are like this. This affected the treatment of \w and \W
3129        when they appeared in character classes, but not when they appeared outside
3130        a character class. The bit map for "word" characters is now created
3131        separately from the results of isalnum() instead of just taking it from the
3132        upper, lower, and digit maps. (Plus the underscore character, of course.)
3134     5. The above bug also affected the handling of POSIX character classes such as
3135        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
3136        permanent tables. Instead, the bit maps for such a class were previously
3137        created as the appropriate unions of the upper, lower, and digit bitmaps.
3138        Now they are created by subtraction from the [[:word:]] class, which has
3139        its own bitmap.
3141     6. The [[:blank:]] character class matches horizontal, but not vertical space.
3142        It is created by subtracting the vertical space characters (\x09, \x0a,
3143        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
3144        subtraction was done in the overall bitmap for a character class, meaning
3145        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
3146        be recognized. This bug has been fixed.
3148     7. Patches from the folks at Google:
3150          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
3151          real life, but is still worth protecting against".
3153          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
3154          regular expressions".
3156          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
3157          have it.
3159          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
3160          "configure" and the latter not, in order to fix a problem somebody had
3161          with compiling the Arg class on HP-UX.
3163          (e) Improve the error-handling of the C++ wrapper a little bit.
3165          (f) New tests for checking recursion limiting.
3167     8. The pcre_memmove() function, which is used only if the environment does not
3168        have a standard memmove() function (and is therefore rarely compiled),
3169        contained two bugs: (a) use of int instead of size_t, and (b) it was not
3170        returning a result (though PCRE never actually uses the result).
3172     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
3173        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
3174        returned instead of calling malloc() with an overflowing number that would
3175        most likely cause subsequent chaos.
3177    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
3179    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
3180        with this option is matched, the nmatch and pmatch options of regexec() are
3181        ignored.
3183    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
3184        provided in case anyone wants to the the POSIX interface with UTF-8
3185        strings.
3187    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
3188        C++ linking (needed for some HP-UX environments).
3190    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
3191        (unused parameter) and in the pcre_printint() function (omitted "default"
3192        switch label when the default is to do nothing).
3194    15. Added some code to make it possible, when PCRE is compiled as a C++
3195        library, to replace subject pointers for pcre_exec() with a smart pointer
3196        class, thus making it possible to process discontinuous strings.
3198    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
3199        much the same function. They were added by different people who were trying
3200        to make PCRE easy to compile on non-Unix systems. It has been suggested
3201        that PCRE_EXPORT be abolished now that there is more automatic apparatus
3202        for compiling on Windows systems. I have therefore replaced it with
3203        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
3204        defaults to "extern" for C or "extern C" for C++, which works fine on
3205        Unix-like systems. It is now possible to override the value of PCRE_DATA_
3206        SCOPE with something explicit in config.h. In addition:
3208        (a) pcreposix.h still had just "extern" instead of either of these macros;
3209            I have replaced it with PCRE_DATA_SCOPE.
3211        (b) Functions such as _pcre_xclass(), which are internal to the library,
3212            but external in the C sense, all had PCRE_EXPORT in their definitions.
3213            This is apparently wrong for the Windows case, so I have removed it.
3214            (It makes no difference on Unix-like systems.)
3216    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
3217        of recursive calls to match(). This is different to MATCH_LIMIT because
3218        that limits the total number of calls to match(), not all of which increase
3219        the depth of recursion. Limiting the recursion depth limits the amount of
3220        stack (or heap if NO_RECURSE is set) that is used. The default can be set
3221        when PCRE is compiled, and changed at run time. A patch from Google adds
3222        this functionality to the C++ interface.
3224    18. Changes to the handling of Unicode character properties:
3226        (a) Updated the table to Unicode 4.1.0.
3228        (b) Recognize characters that are not in the table as "Cn" (undefined).
3230        (c) I revised the way the table is implemented to a much improved format
3231            which includes recognition of ranges. It now supports the ranges that
3232            are defined in UnicodeData.txt, and it also amalgamates other
3233            characters into ranges. This has reduced the number of entries in the
3234            table from around 16,000 to around 3,000, thus reducing its size
3235            considerably. I realized I did not need to use a tree structure after
3236            all - a binary chop search is just as efficient. Having reduced the
3237            number of entries, I extended their size from 6 bytes to 8 bytes to
3238            allow for more data.
3240        (d) Added support for Unicode script names via properties such as \p{Han}.
3242    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
3243        matching that character.
3245    20. When matching a repeated Unicode property with a minimum greater than zero,
3246        (for example \pL{2,}), PCRE could look past the end of the subject if it
3247        reached it while seeking the minimum number of characters. This could
3248        happen only if some of the characters were more than one byte long, because
3249        there is a check for at least the minimum number of bytes.
3251    21. Refactored the implementation of \p and \P so as to be more general, to
3252        allow for more different types of property in future. This has changed the
3253        compiled form incompatibly. Anybody with saved compiled patterns that use
3254        \p or \P will have to recompile them.
3256    22. Added "Any" and "L&" to the supported property types.
3258    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
3259        but give a compile time error if the value is greater than 0xff.
3261    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
3262        accidentally not being installed or uninstalled.
3264    25. The pcre.h file was built from pcre.h.in, but the only changes that were
3265        made were to insert the current release number. This seemed silly, because
3266        it made things harder for people building PCRE on systems that don't run
3267        "configure". I have turned pcre.h into a distributed file, no longer built
3268        by "configure", with the version identification directly included. There is
3269        no longer a pcre.h.in file.
3271        However, this change necessitated a change to the pcre-config script as
3272        well. It is built from pcre-config.in, and one of the substitutions was the
3273        release number. I have updated configure.ac so that ./configure now finds
3274        the release number by grepping pcre.h.
3276    26. Added the ability to run the tests under valgrind.
3279    Version 6.4 05-Sep-05
3280    ---------------------
3282     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
3283        "--" to be printed when multiple files were scanned, even when none of the
3284        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
3285        consider it to be a bug, and have restored the previous behaviour.
3287     2. A couple of code tidies to get rid of compiler warnings.
3289     3. The pcretest program used to cheat by referring to symbols in the library
3290        whose names begin with _pcre_. These are internal symbols that are not
3291        really supposed to be visible externally, and in some environments it is
3292        possible to suppress them. The cheating is now confined to including
3293        certain files from the library's source, which is a bit cleaner.
3295     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
3296        file's purpose clearer.
3298     5. Reorganized pcre_ucp_findchar().
3301    Version 6.3 15-Aug-05
3302    ---------------------
3304     1. The file libpcre.pc.in did not have general read permission in the tarball.
3306     2. There were some problems when building without C++ support:
3308        (a) If C++ support was not built, "make install" and "make test" still
3309            tried to test it.
3311        (b) There were problems when the value of CXX was explicitly set. Some
3312            changes have been made to try to fix these, and ...
3314        (c) --disable-cpp can now be used to explicitly disable C++ support.
3316        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
3317            backslash in a target when C++ was disabled. This confuses some
3318            versions of "make", apparently. Using an intermediate variable solves
3319            this. (Same for CPP_LOBJ.)
3321     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
3322        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
3323        necessary on certain architectures.
3325     4. Added a setting of -export-symbols-regex to the link command to remove
3326        those symbols that are exported in the C sense, but actually are local
3327        within the library, and not documented. Their names all begin with
3328        "_pcre_". This is not a perfect job, because (a) we have to except some
3329        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
3330        available (and never for static libraries). I have made a note to try to
3331        find a way round (a) in the future.
3334    Version 6.2 01-Aug-05
3335    ---------------------
3337     1. There was no test for integer overflow of quantifier values. A construction
3338        such as {1111111111111111} would give undefined results. What is worse, if
3339        a minimum quantifier for a parenthesized subpattern overflowed and became
3340        negative, the calculation of the memory size went wrong. This could have
3341        led to memory overwriting.
3343     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
3345     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
3346        operating environments where this matters.
3348     4. Applied Giuseppe Maxia's patch to add additional features for controlling
3349        PCRE options from within the C++ wrapper.
3351     5. Named capturing subpatterns were not being correctly counted when a pattern
3352        was compiled. This caused two problems: (a) If there were more than 100
3353        such subpatterns, the calculation of the memory needed for the whole
3354        compiled pattern went wrong, leading to an overflow error. (b) Numerical
3355        back references of the form \12, where the number was greater than 9, were
3356        not recognized as back references, even though there were sufficient
3357        previous subpatterns.
3359     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
3360        versions of gcc, e.g. 2.95.4.
3363    Version 6.1 21-Jun-05
3364    ---------------------
3366     1. There was one reference to the variable "posix" in pcretest.c that was not
3367        surrounded by "#if !defined NOPOSIX".
3369     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
3370        the cross-check on the old pcre_info() function, for the benefit of the
3371        cut-down version of PCRE that is currently imported into Exim.
3373     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
3374        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
3375        patterns that start (?i) but I don't think that matters. The use of (?i) is
3376        just an example; this all applies to the other options as well.
3378     4. Since libtool seems to echo the compile commands it is issuing, the output
3379        from "make" can be reduced a bit by putting "@" in front of each libtool
3380        compile command.
3382     5. Patch from the folks at Google for configure.in to be a bit more thorough
3383        in checking for a suitable C++ installation before trying to compile the
3384        C++ stuff. This should fix a reported problem when a compiler was present,
3385        but no suitable headers.
3387     6. The man pages all had just "PCRE" as their title. I have changed them to
3388        be the relevant file name. I have also arranged that these names are
3389        retained in the file doc/pcre.txt, which is a concatenation in text format
3390        of all the man pages except the little individual ones for each function.
3392     7. The NON-UNIX-USE file had not been updated for the different set of source
3393        files that come with release 6. I also added a few comments about the C++
3394        wrapper.
3397    Version 6.0 07-Jun-05
3398    ---------------------
3400     1. Some minor internal re-organization to help with my DFA experiments.
3402     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
3403        didn't matter for the library itself when fully configured, but did matter
3404        when compiling without UCP support, or within Exim, where the ucp files are
3405        not imported.
3407     3. Refactoring of the library code to split up the various functions into
3408        different source modules. The addition of the new DFA matching code (see
3409        below) to a single monolithic source would have made it really too
3410        unwieldy, quite apart from causing all the code to be include in a
3411        statically linked application, when only some functions are used. This is
3412        relevant even without the DFA addition now that patterns can be compiled in
3413        one application and matched in another.
3415        The downside of splitting up is that there have to be some external
3416        functions and data tables that are used internally in different modules of
3417        the library but which are not part of the API. These have all had their
3418        names changed to start with "_pcre_" so that they are unlikely to clash
3419        with other external names.
3421     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
3422        a different (DFA) algorithm. Although it is slower than the original
3423        function, it does have some advantages for certain types of matching
3424        problem.
3426     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
3427        including restarting after a partial match.
3429     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
3430        defined when compiling for Windows was sent to me. I have put it into the
3431        code, though I have no means of testing or verifying it.
3433     7. Added the pcre_refcount() auxiliary function.
3435     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
3436        match before or at the first newline in the subject string. In pcretest,
3437        the /f option on a pattern can be used to set this.
3439     9. A repeated \w when used in UTF-8 mode with characters greater than 256
3440        would behave wrongly. This has been present in PCRE since release 4.0.
3442    10. A number of changes to the pcregrep command:
3444        (a) Refactored how -x works; insert ^(...)$ instead of setting
3445            PCRE_ANCHORED and checking the length, in preparation for adding
3446            something similar for -w.
3448        (b) Added the -w (match as a word) option.
3450        (c) Refactored the way lines are read and buffered so as to have more
3451            than one at a time available.
3453        (d) Implemented a pcregrep test script.
3455        (e) Added the -M (multiline match) option. This allows patterns to match
3456            over several lines of the subject. The buffering ensures that at least
3457            8K, or the rest of the document (whichever is the shorter) is available
3458            for matching (and similarly the previous 8K for lookbehind assertions).
3460        (f) Changed the --help output so that it now says
3462              -w, --word-regex(p)
3464            instead of two lines, one with "regex" and the other with "regexp"
3465            because that confused at least one person since the short forms are the
3466            same. (This required a bit of code, as the output is generated
3467            automatically from a table. It wasn't just a text change.)
3469        (g) -- can be used to terminate pcregrep options if the next thing isn't an
3470            option but starts with a hyphen. Could be a pattern or a path name
3471            starting with a hyphen, for instance.
3473        (h) "-" can be given as a file name to represent stdin.
3475        (i) When file names are being printed, "(standard input)" is used for
3476            the standard input, for compatibility with GNU grep. Previously
3477            "<stdin>" was used.
3479        (j) The option --label=xxx can be used to supply a name to be used for
3480            stdin when file names are being printed. There is no short form.
3482        (k) Re-factored the options decoding logic because we are going to add
3483            two more options that take data. Such options can now be given in four
3484            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
3486        (l) Added the -A, -B, and -C options for requesting that lines of context
3487            around matches be printed.
3489        (m) Added the -L option to print the names of files that do not contain
3490            any matching lines, that is, the complement of -l.
3492        (n) The return code is 2 if any file cannot be opened, but pcregrep does
3493            continue to scan other files.
3495        (o) The -s option was incorrectly implemented. For compatibility with other
3496            greps, it now suppresses the error message for a non-existent or non-
3497            accessible file (but not the return code). There is a new option called
3498            -q that suppresses the output of matching lines, which was what -s was
3499            previously doing.
3501        (p) Added --include and --exclude options to specify files for inclusion
3502            and exclusion when recursing.
3504    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
3505        Hopefully, it now does.
3507    12. Missing cast in pcre_study().
3509    13. Added an "uninstall" target to the makefile.
3511    14. Replaced "extern" in the function prototypes in Makefile.in with
3512        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
3513        world, but is set differently for Windows.
3515    15. Added a second compiling function called pcre_compile2(). The only
3516        difference is that it has an extra argument, which is a pointer to an
3517        integer error code. When there is a compile-time failure, this is set
3518        non-zero, in addition to the error test pointer being set to point to an
3519        error message. The new argument may be NULL if no error number is required
3520        (but then you may as well call pcre_compile(), which is now just a
3521        wrapper). This facility is provided because some applications need a
3522        numeric error indication, but it has also enabled me to tidy up the way
3523        compile-time errors are handled in the POSIX wrapper.
3525    16. Added VPATH=.libs to the makefile; this should help when building with one
3526        prefix path and installing with another. (Or so I'm told by someone who
3527        knows more about this stuff than I do.)
3529    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
3530        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
3531        match everything, including newlines. This is not POSIX-compatible, but
3532        somebody wanted the feature. From pcretest it can be activated by using
3533        both the P and the s flags.
3535    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
3537    19. libpcre.pc was being incorrectly installed as executable.
3539    20. A couple of places in pcretest check for end-of-line by looking for '\n';
3540        it now also looks for '\r' so that it will work unmodified on Windows.
3542    21. Added Google's contributed C++ wrapper to the distribution.
3544    22. Added some untidy missing memory free() calls in pcretest, to keep
3545        Electric Fence happy when testing.
3549    Version 5.0 13-Sep-04
3550    ---------------------
3552     1. Internal change: literal characters are no longer packed up into items
3553        containing multiple characters in a single byte-string. Each character
3554        is now matched using a separate opcode. However, there may be more than one
3555        byte in the character in UTF-8 mode.
3557     2. The pcre_callout_block structure has two new fields: pattern_position and
3558        next_item_length. These contain the offset in the pattern to the next match
3559        item, and its length, respectively.
3561     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
3562        insertion of callouts before each pattern item. Added the /C option to
3563        pcretest to make use of this.
3565     4. On the advice of a Windows user, the lines
3567          #if defined(_WIN32) || defined(WIN32)
3568          _setmode( _fileno( stdout ), 0x8000 );
3569          #endif  /* defined(_WIN32) || defined(WIN32) */
3571        have been added to the source of pcretest. This apparently does useful
3572        magic in relation to line terminators.
3574     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
3575        for the benefit of those environments where the "b" makes a difference.
3577     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
3578        to know about it. I have put a hack into configure.in that adds in code
3579        to set GCC=yes if CC=icc. This seems to end up at a point in the
3580        generated configure script that is early enough to affect the setting of
3581        compiler options, which is what is needed, but I have no means of testing
3582        whether it really works. (The user who reported this had patched the
3583        generated configure script, which of course I cannot do.)