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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.10 03 May-2010  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.
10    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
11        this macro is never tested and has no effect, because the work to support
12        coverage involves only compiling and linking options and special targets in
13        the Makefile. The comment in config.h implied that defining the macro would
14        enable coverage support, which is totally false. There was also support for
15        setting this macro in the CMake files (my fault, I just copied it from
16        configure). SUPPORT_GCOV has now been removed.
18    3.  Make a small performance improvement in strlen16() and strlen32() in
19        pcretest.
21    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
22        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
23        these cases). There was also one in pcretest.c.
25    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
27    6.  In UTF mode, the code for checking whether a group could match an empty
28        string (which is used for indefinitely repeated groups to allow for
29        breaking an infinite loop) was broken when the group contained a repeated
30        negated single-character class with a character that occupied more than one
31        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
32        UTF-8 mode). The effect was undefined: the group might or might not be
33        deemed as matching an empty string, or the program might have crashed.
35    7.  The code for checking whether a group could match an empty string was not
36        recognizing that \h, \H, \v, \V, and \R must match a character.
38    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
39        an empty string. If it can, pcretest shows this in its information output.
42    Version 8.33 28-May-2013
43    --------------------------
45    1.  Added 'U' to some constants that are compared to unsigned integers, to
46        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
47        variables that are added to signed variables, to ensure the result is
48        signed and can be negated.
50    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
51        CMake config files.
53    3.  Revise the creation of config.h.generic so that all boolean macros are
54        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
55        overriding via -D on the command line possible.
57    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
58        to unsigned int is reported to make a quite noticeable speed difference in
59        a specific Windows environment. Testing on Linux did also appear to show
60        some benefit (and it is clearly not harmful). Also fixed the definition of
61        Xop which should be unsigned.
63    5.  Related to (4), changing the definition of the intermediate variable cc
64        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
65        improvements.
67    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
68        unnecessary spaces.
70    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
71        and later.
73    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
75    9.  Optimizing fast_forward_start_bits in JIT.
77    10. Adding support for callouts in JIT, and fixing some issues revealed
78        during this work. Namely:
80        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
82        (b) Minimum length was not checked before the matching is started.
84    11. The value of capture_last that is passed to callouts was incorrect in some
85        cases when there was a capture on one path that was subsequently abandoned
86        after a backtrack. Also, the capture_last value is now reset after a
87        recursion, since all captures are also reset in this case.
89    12. The interpreter no longer returns the "too many substrings" error in the
90        case when an overflowing capture is in a branch that is subsequently
91        abandoned after a backtrack.
93    13. In the pathological case when an offset vector of size 2 is used, pcretest
94        now prints out the matched string after a yield of 0 or 1.
96    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
97        Only supported by the JIT compiler at the moment.
99    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
101    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
102        offset of the starting point of the matching process, provided the offsets
103        vector is large enough.
105    17. The \A escape now records a lookbehind value of 1, though its execution
106        does not actually inspect the previous character. This is to ensure that,
107        in partial multi-segment matching, at least one character from the old
108        segment is retained when a new segment is processed. Otherwise, if there
109        are no lookbehinds in the pattern, \A might match incorrectly at the start
110        of a new segment.
112    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
114    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
115        gives some modest performance improvement in 8-bit mode.
117    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
118        be expressed in certain programming languages using Universal Character
119        Names.
121    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
122        which points out that "non characters" are not "characters that may not
123        appear in Unicode strings" but rather "characters that are reserved for
124        internal use and have only local meaning".
126    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
127        there was a conditional group that depended on an assertion, if the
128        assertion was false, the callout that immediately followed the alternation
129        in the condition was skipped when pcre_exec() was used for matching.
131    23. Allow an explicit callout to be inserted before an assertion that is the
132        condition for a conditional group, for compatibility with automatic
133        callouts, which always insert a callout at this point.
135    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
136        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
138    25. (*PRUNE) is now supported by the JIT compiler.
140    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
142    27. Fix the case where there are two or more SKIPs with arguments that may be
143        ignored.
145    28. (*SKIP) is now supported by the JIT compiler.
147    29. (*THEN) is now supported by the JIT compiler.
149    30. Update RunTest with additional test selector options.
151    31. The way PCRE handles backtracking verbs has been changed in two ways.
153        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
154        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
155        backtracking. In some cases this makes it more Perl-compatible, but Perl's
156        rather obscure rules do not always do the same thing.
158        (2) Previously, backtracking verbs were confined within assertions. This is
159        no longer the case for positive assertions, except for (*ACCEPT). Again,
160        this sometimes improves Perl compatibility, and sometimes does not.
162    32. A number of tests that were in test 2 because Perl did things differently
163        have been moved to test 1, because either Perl or PCRE has changed, and
164        these tests are now compatible.
166    32. Backtracking control verbs are now handled in the same way in JIT and
167        interpreter.
169    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
170        contained a forward subroutine reference caused a compile error.
172    34. Auto-detect and optimize limited repetitions in JIT.
174    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
175        blocking (*UTF) etc.
177    36. In the interpreter, maximizing pattern repetitions for characters and
178        character types now use tail recursion, which reduces stack usage.
180    37. The value of the max lookbehind was not correctly preserved if a compiled
181        and saved regex was reloaded on a host of different endianness.
183    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
184        of the compiled pattern block, expand the flags field from 16 to 32 bits
185        because it was almost full.
187    39. Try madvise first before posix_madvise.
189    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
190        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
191        original change locked out all matches of empty strings. This has been
192        changed so that one match of an empty string per line is recognized.
193        Subsequent searches on the same line (for colouring or for --only-matching,
194        for example) do not recognize empty strings.
196    41. Applied a user patch to fix a number of spelling mistakes in comments.
198    42. Data lines longer than 65536 caused pcretest to crash.
200    43. Clarified the data type for length and startoffset arguments for pcre_exec
201        and pcre_dfa_exec in the function-specific man pages, where they were
202        explicitly stated to be in bytes, never having been updated. I also added
203        some clarification to the pcreapi man page.
205    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
206        a segmentation fault.
209    Version 8.32 30-November-2012
210    -----------------------------
212    1.  Improved JIT compiler optimizations for first character search and single
213        character iterators.
215    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
216        Patch by Daniel Richard G.
218    3.  Single character iterator optimizations in the JIT compiler.
220    4.  Improved JIT compiler optimizations for character ranges.
222    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
223        Reported by Giuseppe D'Angelo.
225    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
226        of a line, was being set incorrectly in cases where .* appeared inside
227        atomic brackets at the start of a pattern, or where there was a subsequent
228        *PRUNE or *SKIP.
230    7.  Improved instruction cache flush for POWER/PowerPC.
231        Patch by Daniel Richard G.
233    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
234        grep:
236        (a) There is now no limit to the number of patterns to be matched.
238        (b) An error is given if a pattern is too long.
240        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
241            are now supported.
243        (d) --exclude-from and --include-from (multiple use) have been added.
245        (e) Exclusions and inclusions now apply to all files and directories, not
246            just to those obtained from scanning a directory recursively.
248        (f) Multiple uses of -f and --file-list are now supported.
250        (g) In a Windows environment, the default for -d has been changed from
251            "read" (the GNU grep default) to "skip", because otherwise the presence
252            of a directory in the file list provokes an error.
254        (h) The documentation has been revised and clarified in places.
256    9.  Improve the matching speed of capturing brackets.
258    10. Changed the meaning of \X so that it now matches a Unicode extended
259        grapheme cluster.
261    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
262        out POSIX threads when JIT support is configured.
264    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
266    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
267        structure could go wrong in environments where size_t is not the same size
268        as int.
270    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
271        set.
273    15. The EBCDIC support had decayed; later updates to the code had included
274        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
275        general tidy up of EBCDIC-related issues, and the documentation was also
276        not quite right. There is now a test that can be run on ASCII systems to
277        check some of the EBCDIC-related things (but is it not a full test).
279    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
280        in a small tidy to the code.
282    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
284    18. If the --only-matching (-o) option in pcregrep is specified multiple
285        times, each one causes appropriate output. For example, -o1 -o2 outputs the
286        substrings matched by the 1st and 2nd capturing parentheses. A separating
287        string can be specified by --om-separator (default empty).
289    19. Improving the first n character searches.
291    20. Turn case lists for horizontal and vertical white space into macros so that
292        they are defined only once.
294    21. This set of changes together give more compatible Unicode case-folding
295        behaviour for characters that have more than one other case when UCP
296        support is available.
298        (a) The Unicode property table now has offsets into a new table of sets of
299            three or more characters that are case-equivalent. The MultiStage2.py
300            script that generates these tables (the pcre_ucd.c file) now scans
301            CaseFolding.txt instead of UnicodeData.txt for character case
302            information.
304        (b) The code for adding characters or ranges of characters to a character
305            class has been abstracted into a generalized function that also handles
306            case-independence. In UTF-mode with UCP support, this uses the new data
307            to handle characters with more than one other case.
309        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
310            whose other case is greater than 256 are now correctly matched
311            caselessly. Previously, the high codepoint matched the low one, but not
312            vice versa.
314        (d) The processing of \h, \H, \v, and \ in character classes now makes use
315            of the new class addition function, using character lists defined as
316            macros alongside the case definitions of 20 above.
318        (e) Caseless back references now work with characters that have more than
319            one other case.
321        (f) General caseless matching of characters with more than one other case
322            is supported.
324    22. Unicode character properties were updated from Unicode 6.2.0
326    23. Improved CMake support under Windows. Patch by Daniel Richard G.
328    24. Add support for 32-bit character strings, and UTF-32
330    25. Major JIT compiler update (code refactoring and bugfixing).
331        Experimental Sparc 32 support is added.
333    26. Applied a modified version of Daniel Richard G's patch to create
334        pcre.h.generic and config.h.generic by "make" instead of in the
335        PrepareRelease script.
337    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
338        pcre_compile.c when checking for a zero character.
340    28. Introducing a native interface for JIT. Through this interface, the compiled
341        machine code can be directly executed. The purpose of this interface is to
342        provide fast pattern matching, so several sanity checks are not performed.
343        However, feature tests are still performed. The new interface provides
344        1.4x speedup compared to the old one.
346    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
347        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
348        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
350    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
351        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
352        the "old" RFC 2279). Instead, it ended up passing a negative length to
353        pcre_exec().
355    31. Add support for GCC's visibility feature to hide internal functions.
357    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
358        "unknown -C option" after outputting 0 or 1.
360    33. There is now support for generating a code coverage report for the test
361        suite in environments where gcc is the compiler and lcov is installed. This
362        is mainly for the benefit of the developers.
364    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
365        unaddressable using valgrind annotations, allowing valgrind to detect
366        invalid memory accesses. This is mainly for the benefit of the developers.
368    25. (*UTF) can now be used to start a pattern in any of the three libraries.
370    26. Give configure error if --enable-cpp but no C++ compiler found.
373    Version 8.31 06-July-2012
374    -------------------------
376    1.  Fixing a wrong JIT test case and some compiler warnings.
378    2.  Removed a bashism from the RunTest script.
380    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
381        to unsigned type, result still unsigned" that was given by an MS compiler
382        on encountering the code "-sizeof(xxx)".
384    4.  Partial matching support is added to the JIT compiler.
386    5.  Fixed several bugs concerned with partial matching of items that consist
387        of more than one character:
389        (a) /^(..)\1/ did not partially match "aba" because checking references was
390            done on an "all or nothing" basis. This also applied to repeated
391            references.
393        (b) \R did not give a hard partial match if \r was found at the end of the
394            subject.
396        (c) \X did not give a hard partial match after matching one or more
397            characters at the end of the subject.
399        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
400            a partial match for the string "\r".
402        (e) When newline was set to CRLF, the metacharacter "." did not recognize
403            a partial match for a CR character at the end of the subject string.
405    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
406        running pcretest, the text "(JIT)" added to the output whenever JIT is
407        actually used to run the match.
409    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
410        or /S+[+] with a digit between 1 and 7.
412    8.  OP_NOT now supports any UTF character not just single-byte ones.
414    9.  (*MARK) control verb is now supported by the JIT compiler.
416    10. The command "./RunTest list" lists the available tests without actually
417        running any of them. (Because I keep forgetting what they all are.)
421    12. Applied a (slightly modified) user-supplied patch that improves performance
422        when the heap is used for recursion (compiled with --disable-stack-for-
423        recursion). Instead of malloc and free for each heap frame each time a
424        logical recursion happens, frames are retained on a chain and re-used where
425        possible. This sometimes gives as much as 30% improvement.
427    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
428        call.
430    14. As documented, (*COMMIT) is now confined to within a positive assertion.
432    15. It is now possible to link pcretest with libedit as an alternative to
433        libreadline.
435    16. (*COMMIT) control verb is now supported by the JIT compiler.
437    17. The Unicode data tables have been updated to Unicode 6.1.0.
439    18. Added --file-list option to pcregrep.
441    19. Added binary file support to pcregrep, including the -a, --binary-files,
442        -I, and --text options.
444    20. The madvise function is renamed for posix_madvise for QNX compatibility
445        reasons. Fixed by Giuseppe D'Angelo.
447    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
449    22. Changed the option for creating symbolic links for 16-bit man pages from
450        -s to -sf so that re-installing does not cause issues.
452    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
454    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
455        matches in certain environments (the workspace was not being correctly
456        retained). Also added to pcre_dfa_exec() a simple plausibility check on
457        some of the workspace data at the beginning of a restart.
459    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
460        was not doing so when it should - probably a typo introduced by SVN 528
461        (change 8.10/14).
463    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
464        \w+ when the character tables indicated that \x{c4} was a word character.
465        There were several related cases, all because the tests for doing a table
466        lookup were testing for characters less than 127 instead of 255.
468    27. If a pattern contains capturing parentheses that are not used in a match,
469        their slots in the ovector are set to -1. For those that are higher than
470        any matched groups, this happens at the end of processing. In the case when
471        there were back references that the ovector was too small to contain
472        (causing temporary malloc'd memory to be used during matching), and the
473        highest capturing number was not used, memory off the end of the ovector
474        was incorrectly being set to -1. (It was using the size of the temporary
475        memory instead of the true size.)
477    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
478        ovector size, it uses memory at the end of the block that it has got.
480    29. Check for an overlong MARK name and give an error at compile time. The
481        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
483    30. JIT compiler update.
485    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
486        Rill for the patch.
488    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
490    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
492    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
493        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
494        was enabled.
496    35. Improve JIT code generation for greedy plus quantifier.
498    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
499        1 to "aa" instead of to an empty string. The bug affected repeated groups
500        that could potentially match an empty string.
502    37. Optimizing single character iterators in JIT.
504    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
505        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
506        codepoints that are too big for the mode are faulted, and in a UTF mode,
507        disallowed codepoints are also faulted.
509    39. If PCRE was compiled with UTF support, in three places in the DFA
510        matcher there was code that should only have been obeyed in UTF mode, but
511        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
512        processing when bytes with values greater than 127 were present. In 16-bit
513        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
514        both cases the values are those that cannot be the first data item in a UTF
515        character. The three items that might have provoked this were recursions,
516        possessively repeated groups, and atomic groups.
518    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
519        and pcregrep, because some OS require shared objects to be explicitly
520        passed to ld, causing the link step to fail if they are not.
522    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
523        mode, patterns that started with \h* or \R* might be incorrectly matched.
526    Version 8.30 04-February-2012
527    -----------------------------
529    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
530        name is defined in ctype.h.
532    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
533        only in quite long subpatterns.
535    3.  Removed the function pcre_info(), which has been obsolete and deprecated
536        since it was replaced by pcre_fullinfo() in February 2000.
538    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
539        match a (*MARK), and the match failed at the start of the subject, a
540        reference to memory before the start of the subject could occur. This bug
541        was introduced by fix 17 of release 8.21.
543    5.  A reference to an unset group with zero minimum repetition was giving
544        totally wrong answers (in non-JavaScript-compatibility mode). For example,
545        /(another)?(\1?)test/ matched against "hello world test". This bug was
546        introduced in release 8.13.
548    6.  Add support for 16-bit character strings (a large amount of work involving
549        many changes and refactorings).
551    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
552        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
553        from a file.
555    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
556        rounding is not applied in this particular case).
558    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
559        if they appear, or are escaped, in patterns.
561    10. Get rid of a number of -Wunused-but-set-variable warnings.
563    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
564        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
565        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
566        also returns the mark "x". This bug applied to capturing parentheses,
567        non-capturing parentheses, and atomic parentheses. It also applied to some
568        assertions.
570    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
571        information out of configure.ac instead of relying on pcre.h.generic, which
572        is not stored in the repository.
574    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
575        -lreadline.
577    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
579    15. Applied Graycode's patch to put the top-level frame on the stack rather
580        than the heap when not using the stack for recursion. This gives a
581        performance improvement in many cases when recursion is not deep.
583    16. Experimental code added to "pcretest -C" to output the stack frame size.
586    Version 8.21 12-Dec-2011
587    ------------------------
589    1.  Updating the JIT compiler.
591    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
592        are added as well.
594    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
595        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
596        calling _pcre_jit_exec. Some extra comments are added.
598    4.  (*MARK) settings inside atomic groups that do not contain any capturing
599        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
600        was introduced by change 18 for 8.20.
602    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
603        ECMA-262 standard.
605    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
606        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
607        This bug was probably introduced by change 9 of 8.13.
609    7.  While fixing 6 above, I noticed that a number of other items were being
610        incorrectly rejected as "not fixed length". This arose partly because newer
611        opcodes had not been added to the fixed-length checking code. I have (a)
612        corrected the bug and added tests for these items, and (b) arranged for an
613        error to occur if an unknown opcode is encountered while checking for fixed
614        length instead of just assuming "not fixed length". The items that were
615        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
616        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
617        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
619    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
620        being incorrectly compiled and would have given unpredicatble results.
622    9.  A possessively repeated subpattern with minimum repeat count greater than
623        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
624        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
625        the first (A) could occur when it should not.
627    10. Add a cast and remove a redundant test from the code.
629    11. JIT should use pcre_malloc/pcre_free for allocation.
631    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
632        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
633        is anything other than /usr, -L is still shown).
635    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
637    14. Perl does not support \N without a following name in a [] class; PCRE now
638        also gives an error.
640    15. If a forward reference was repeated with an upper limit of around 2000,
641        it caused the error "internal error: overran compiling workspace". The
642        maximum number of forward references (including repeats) was limited by the
643        internal workspace, and dependent on the LINK_SIZE. The code has been
644        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
645        the default depends on LINK_SIZE. There is a new upper limit (for safety)
646        of around 200,000 forward references. While doing this, I also speeded up
647        the filling in of repeated forward references.
649    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
650        incorrectly expecting the subject to contain another "a" after the start.
652    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
653        in the match, the SKIP should be ignored. This was not happening; instead
654        the SKIP was being treated as NOMATCH. For patterns such as
655        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
656        tested.
658    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
659        now much more compatible with Perl, in particular in cases where the result
660        is a non-match for a non-anchored pattern. For example, if
661        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
662        "m", where previously it did not return a name. A side effect of this
663        change is that for partial matches, the last encountered mark name is
664        returned, as for non matches. A number of tests that were previously not
665        Perl-compatible have been moved into the Perl-compatible test files. The
666        refactoring has had the pleasing side effect of removing one argument from
667        the match() function, thus reducing its stack requirements.
669    19. If the /S+ option was used in pcretest to study a pattern using JIT,
670        subsequent uses of /S (without +) incorrectly behaved like /S+.
672    21. Retrieve executable code size support for the JIT compiler and fixing
673        some warnings.
675    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
676        not work when the shorter character appeared right at the end of the
677        subject string.
679    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
680        systems.
682    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
683        output it when the /M option is used in pcretest.
685    25. The CheckMan script was not being included in the distribution. Also, added
686        an explicit "perl" to run Perl scripts from the PrepareRelease script
687        because this is reportedly needed in Windows.
689    26. If study data was being save in a file and studying had not found a set of
690        "starts with" bytes for the pattern, the data written to the file (though
691        never used) was taken from uninitialized memory and so caused valgrind to
692        complain.
694    27. Updated RunTest.bat as provided by Sheri Pierce.
696    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
698    29. Computation of memory usage for the table of capturing group names was
699        giving an unnecessarily large value.
702    Version 8.20 21-Oct-2011
703    ------------------------
705    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
706        a POSIX class. After further experiments with Perl, which convinced me that
707        Perl has bugs and confusions, a closing square bracket is no longer allowed
708        in a POSIX name. This bug also affected patterns with classes that started
709        with full stops.
711    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
712        captured substring, but while checking the failing first alternative,
713        substring 1 is temporarily captured. If the output vector supplied to
714        pcre_exec() was not big enough for this capture, the yield of the function
715        was still zero ("insufficient space for captured substrings"). This cannot
716        be totally fixed without adding another stack variable, which seems a lot
717        of expense for a edge case. However, I have improved the situation in cases
718        such as /(a)(b)x|abc/ matched against "abc", where the return code
719        indicates that fewer than the maximum number of slots in the ovector have
720        been set.
722    3.  Related to (2) above: when there are more back references in a pattern than
723        slots in the output vector, pcre_exec() uses temporary memory during
724        matching, and copies in the captures as far as possible afterwards. It was
725        using the entire output vector, but this conflicts with the specification
726        that only 2/3 is used for passing back captured substrings. Now it uses
727        only the first 2/3, for compatibility. This is, of course, another edge
728        case.
730    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
731        main code base, and can be used by building with --enable-jit. When this is
732        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
733        runtime --no-jit option is given.
735    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
736        ovector, the return from the function was zero, implying that there were
737        other matches that did not fit. The correct "exactly full" value is now
738        returned.
740    6.  If a subpattern that was called recursively or as a subroutine contained
741        (*PRUNE) or any other control that caused it to give a non-standard return,
742        invalid errors such as "Error -26 (nested recursion at the same subject
743        position)" or even infinite loops could occur.
745    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
746        computing the minimum length on reaching *ACCEPT, and so ended up with the
747        wrong value of 1 rather than 0. Further investigation indicates that
748        computing a minimum subject length in the presence of *ACCEPT is difficult
749        (think back references, subroutine calls), and so I have changed the code
750        so that no minimum is registered for a pattern that contains *ACCEPT.
752    8.  If (*THEN) was present in the first (true) branch of a conditional group,
753        it was not handled as intended. [But see 16 below.]
755    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
756        Sheri Pierce.
758    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
759        the first byte in a match must be "a".
761    11. Change 17 for 8.13 increased the recursion depth for patterns like
762        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
763        pattern contains any instances of (*THEN). If it does not, the old
764        optimizations are restored. It would be nice to do this on a per-group
765        basis, but at the moment that is not feasible.
767    12. In some environments, the output of pcretest -C is CRLF terminated. This
768        broke RunTest's code that checks for the link size. A single white space
769        character after the value is now allowed for.
771    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
772        For "fr", it uses the Windows-specific input and output files.
774    14. If (*THEN) appeared in a group that was called recursively or as a
775        subroutine, it did not work as intended. [But see next item.]
777    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
778        pattern fragments (but not containing any | characters). If A and B are
779        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
780        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
781        D. In other words, Perl considers parentheses that do not contain any |
782        characters to be part of a surrounding alternative, whereas PCRE was
783        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
784        differently. PCRE now behaves in the same way as Perl, except in the case
785        of subroutine/recursion calls such as (?1) which have in any case always
786        been different (but PCRE had them first :-).
788    16. Related to 15 above: Perl does not treat the | in a conditional group as
789        creating alternatives. Such a group is treated in the same way as an
790        ordinary group without any | characters when processing (*THEN). PCRE has
791        been changed to match Perl's behaviour.
793    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
794        RunGrepTest script failed.
796    18. Change 22 for version 13 caused atomic groups to use more stack. This is
797        inevitable for groups that contain captures, but it can lead to a lot of
798        stack use in large patterns. The old behaviour has been restored for atomic
799        groups that do not contain any capturing parentheses.
801    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
802        suppress the check for a minimum subject length at run time. (If it was
803        given to pcre_exec() or pcre_dfa_exec() it did work.)
805    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
806        fail to work when decoding hex characters in data strings in EBCDIC
807        environments.
809    21. It appears that in at least one Mac OS environment, the isxdigit() function
810        is implemented as a macro that evaluates to its argument more than once,
811        contravening the C 90 Standard (I haven't checked a later standard). There
812        was an instance in pcretest which caused it to go wrong when processing
813        \x{...} escapes in subject strings. The has been rewritten to avoid using
814        things like p++ in the argument of isxdigit().
817    Version 8.13 16-Aug-2011
818    ------------------------
820    1.  The Unicode data tables have been updated to Unicode 6.0.0.
822    2.  Two minor typos in pcre_internal.h have been fixed.
824    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
825        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
826        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
828    4.  There were a number of related bugs in the code for matching backrefences
829        caselessly in UTF-8 mode when codes for the characters concerned were
830        different numbers of bytes. For example, U+023A and U+2C65 are an upper
831        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
832        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
833        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
834        2-byte code at the end of the subject (it thought there wasn't enough data
835        left).
837    5.  Comprehensive information about what went wrong is now returned by
838        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
839        as the output vector has at least 2 elements. The offset of the start of
840        the failing character and a reason code are placed in the vector.
842    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
843        now returned is for the first byte of the failing character, instead of the
844        last byte inspected. This is an incompatible change, but I hope it is small
845        enough not to be a problem. It makes the returned offset consistent with
846        pcre_exec() and pcre_dfa_exec().
848    7.  pcretest now gives a text phrase as well as the error number when
849        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
850        failure, the offset and reason code are output.
852    8.  When \R was used with a maximizing quantifier it failed to skip backwards
853        over a \r\n pair if the subsequent match failed. Instead, it just skipped
854        back over a single character (\n). This seems wrong (because it treated the
855        two characters as a single entity when going forwards), conflicts with the
856        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
857        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
858        has been changed.
860    9.  Some internal refactoring has changed the processing so that the handling
861        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
862        time (the PCRE_DOTALL option was changed this way some time ago: version
863        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
864        which was always a bit of a fudge. It also means that there is one less
865        argument for the match() function, which reduces its stack requirements
866        slightly. This change also fixes an incompatibility with Perl: the pattern
867        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
869    10. More internal refactoring has drastically reduced the number of recursive
870        calls to match() for possessively repeated groups such as (abc)++ when
871        using pcre_exec().
873    11. While implementing 10, a number of bugs in the handling of groups were
874        discovered and fixed:
876        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
877        (a|)*(?1) gave a compile-time internal error.
878        ((a|)+)+  did not notice that the outer group could match an empty string.
879        (^a|^)+   was not marked as anchored.
880        (.*a|.*)+ was not marked as matching at start or after a newline.
882    12. Yet more internal refactoring has removed another argument from the match()
883        function. Special calls to this function are now indicated by setting a
884        value in a variable in the "match data" data block.
886    13. Be more explicit in pcre_study() instead of relying on "default" for
887        opcodes that mean there is no starting character; this means that when new
888        ones are added and accidentally left out of pcre_study(), testing should
889        pick them up.
891    14. The -s option of pcretest has been documented for ages as being an old
892        synonym of -m (show memory usage). I have changed it to mean "force study
893        for every regex", that is, assume /S for every regex. This is similar to -i
894        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
895        using it. It makes it easier to run collections of tests with and without
896        study enabled, and thereby test pcre_study() more easily. All the standard
897        tests are now run with and without -s (but some patterns can be marked as
898        "never study" - see 20 below).
900    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
901        restoration of the capturing data to the outer values was not happening
902        correctly.
904    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
905        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
906        pattern had matched an empty string, and so incorrectly returned a no
907        match.
909    17. There was optimizing code for the last branch of non-capturing parentheses,
910        and also for the obeyed branch of a conditional subexpression, which used
911        tail recursion to cut down on stack usage. Unfortunately, now that there is
912        the possibility of (*THEN) occurring in these branches, tail recursion is
913        no longer possible because the return has to be checked for (*THEN). These
914        two optimizations have therefore been removed. [But see 8.20/11 above.]
916    18. If a pattern containing \R was studied, it was assumed that \R always
917        matched two bytes, thus causing the minimum subject length to be
918        incorrectly computed because \R can also match just one byte.
920    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
921        was incorrectly computed.
923    20. If /S is present twice on a test pattern in pcretest input, it now
924        *disables* studying, thereby overriding the use of -s on the command line
925        (see 14 above). This is necessary for one or two tests to keep the output
926        identical in both cases.
928    21. When (*ACCEPT) was used in an assertion that matched an empty string and
929        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
931    22. When an atomic group that contained a capturing parenthesis was
932        successfully matched, but the branch in which it appeared failed, the
933        capturing was not being forgotten if a higher numbered group was later
934        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
935        group 1 to "a", when in fact it should be unset. This applied to multi-
936        branched capturing and non-capturing groups, repeated or not, and also to
937        positive assertions (capturing in negative assertions does not happen
938        in PCRE) and also to nested atomic groups.
940    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
941        subject after a captured substring, to make it easier to tell which of a
942        number of identical substrings has been captured.
944    24. The way atomic groups are processed by pcre_exec() has been changed so that
945        if they are repeated, backtracking one repetition now resets captured
946        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
947        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
948        "aaa". Previously, it would have been "a". As part of this code
949        refactoring, the way recursive calls are handled has also been changed.
951    25. If an assertion condition captured any substrings, they were not passed
952        back unless some other capturing happened later. For example, if
953        (?(?=(a))a) was matched against "a", no capturing was returned.
955    26. When studying a pattern that contained subroutine calls or assertions,
956        the code for finding the minimum length of a possible match was handling
957        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
958        group 1 called group 2 while simultaneously a separate group 2 called group
959        1). A stack overflow occurred in this case. I have fixed this by limiting
960        the recursion depth to 10.
962    27. Updated RunTest.bat in the distribution to the version supplied by Tom
963        Fortmann. This supports explicit test numbers on the command line, and has
964        argument validation and error reporting.
966    28. An instance of \X with an unlimited repeat could fail if at any point the
967        first character it looked at was a mark character.
969    29. Some minor code refactoring concerning Unicode properties and scripts
970        should reduce the stack requirement of match() slightly.
972    30. Added the '=' option to pcretest to check the setting of unused capturing
973        slots at the end of the pattern, which are documented as being -1, but are
974        not included in the return count.
976    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
977        compiled something random. Now it gives a compile-time error (as does
978        Perl).
980    32. A *MARK encountered during the processing of a positive assertion is now
981        recorded and passed back (compatible with Perl).
983    33. If --only-matching or --colour was set on a pcregrep call whose pattern
984        had alternative anchored branches, the search for a second match in a line
985        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
986        matched the line "0102" twice. The same bug affected patterns that started
987        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
988        twice.
990    34. Previously, PCRE did not allow quantification of assertions. However, Perl
991        does, and because of capturing effects, quantifying parenthesized
992        assertions may at times be useful. Quantifiers are now allowed for
993        parenthesized assertions.
995    35. A minor code tidy in pcre_compile() when checking options for \R usage.
997    36. \g was being checked for fancy things in a character class, when it should
998        just be a literal "g".
1000    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1001        appearance of a nested POSIX class supersedes an apparent external class.
1002        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1003        unescaped square brackets may also appear as part of class names. For
1004        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1005        more like Perl. (But see 8.20/1 above.)
1007    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1008        was because it thought it was \N{name}, which is not supported).
1010    39. Add minix to OS list not supporting the -S option in pcretest.
1012    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1013        cannot analyze patterns in sufficient detail to catch mutual recursions
1014        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1015        subgroup is called recursively as a subpattern for a second time at the
1016        same position in the subject string. In previous releases this might have
1017        been caught by the recursion limit, or it might have run out of stack.
1019    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1020        happen only once. PCRE was, however incorrectly giving a compile time error
1021        "recursive call could loop indefinitely" because it cannot analyze the
1022        pattern in sufficient detail. The compile time test no longer happens when
1023        PCRE is compiling a conditional subpattern, but actual runaway loops are
1024        now caught at runtime (see 40 above).
1026    42. It seems that Perl allows any characters other than a closing parenthesis
1027        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1028        has been changed to be the same.
1030    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1031        as not to get warnings when autogen.sh is called. Also changed
1032        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1034    44. To help people who use pcregrep to scan files containing exceedingly long
1035        lines, the following changes have been made:
1037        (a) The default value of the buffer size parameter has been increased from
1038            8K to 20K. (The actual buffer used is three times this size.)
1040        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1041            PCRE is built.
1043        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1044            to be set at run time.
1046        (d) Numerical values in pcregrep options can be followed by K or M, for
1047            example --buffer-size=50K.
1049        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1050            given and the return code is set to 2.
1052    45. Add a pointer to the latest mark to the callout data block.
1054    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1055        partial match of an empty string instead of no match. This was specific to
1056        the use of ".".
1058    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1059        complete match instead of a partial match. This bug was dependent on both
1060        the PCRE_UTF8 and PCRE_DOTALL options being set.
1062    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1063        starting byte set, because \b was not being ignored.
1066    Version 8.12 15-Jan-2011
1067    ------------------------
1069    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1070        checks for such things as part of the documentation building process.
1072    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1073        --match-limit and --recursion-limit options (added for 8.11). In
1074        particular, this made one of the standard tests fail. (The integer value
1075        went into the wrong half of a long int.)
1077    3.  If the --colour option was given to pcregrep with -v (invert match), it
1078        did strange things, either producing crazy output, or crashing. It should,
1079        of course, ignore a request for colour when reporting lines that do not
1080        match.
1082    4.  Another pcregrep bug caused similar problems if --colour was specified with
1083        -M (multiline) and the pattern match finished with a line ending.
1085    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1086        matched in multiline mode, the following line was shown as part of the
1087        match. This seems wrong, so I have changed it.
1089    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1090        the check for further matches in the same line (so they could be coloured)
1091        to overrun the end of the current line. If another match was found, it was
1092        incorrectly shown (and then shown again when found in the next line).
1094    7.  If pcregrep was compiled under Windows, there was a reference to the
1095        function pcregrep_exit() before it was defined. I am assuming this was
1096        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1097        reported by a user. I've moved the definition above the reference.
1100    Version 8.11 10-Dec-2010
1101    ------------------------
1103    1.  (*THEN) was not working properly if there were untried alternatives prior
1104        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1105        backtracked to try for "b" instead of moving to the next alternative branch
1106        at the same level (in this case, to look for "c"). The Perl documentation
1107        is clear that when (*THEN) is backtracked onto, it goes to the "next
1108        alternative in the innermost enclosing group".
1110    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1111        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1112        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1113        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1114        (*THEN).
1116    3.  If \s appeared in a character class, it removed the VT character from
1117        the class, even if it had been included by some previous item, for example
1118        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1119        of \s, but is part of the POSIX "space" class.)
1121    4.  A partial match never returns an empty string (because you can always
1122        match an empty string at the end of the subject); however the checking for
1123        an empty string was starting at the "start of match" point. This has been
1124        changed to the "earliest inspected character" point, because the returned
1125        data for a partial match starts at this character. This means that, for
1126        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1127        (previously it gave "no match").
1129    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1130        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1131        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1132        has an implication that the given string is incomplete (because a partial
1133        match is preferred over a full match). For this reason, these items now
1134        give a partial match in this situation. [Aside: previously, the one case
1135        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1136        match rather than a full match, which was wrong by the old rules, but is
1137        now correct.]
1139    6.  There was a bug in the handling of #-introduced comments, recognized when
1140        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1141        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1142        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1143        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1144        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1145        places in pcre_compile().
1147    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1148        comments when looking ahead for named forward references to subpatterns,
1149        the only newline sequence it recognized was NL. It now handles newlines
1150        according to the set newline convention.
1152    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1153        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1154        cater for a lack of strerror(). These oversights have been fixed.
1156    9.  Added --match-limit and --recursion-limit to pcregrep.
1158    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1160    11. When the -o option was used, pcregrep was setting a return code of 1, even
1161        when matches were found, and --line-buffered was not being honoured.
1163    12. Added an optional parentheses number to the -o and --only-matching options
1164        of pcregrep.
1166    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1167        can match an empty string. The code to do it in pcretest and pcredemo
1168        needed fixing:
1170        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1171            only one byte after an empty string match just before CRLF (this case
1172            just got forgotten; "any" and "anycrlf" were OK).
1174        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1175            mode when an empty string match preceded an ASCII character followed by
1176            a non-ASCII character. (The code for advancing by one character rather
1177            than one byte was nonsense.)
1179        (c) The pcredemo.c sample program did not have any code at all to handle
1180            the cases when CRLF is a valid newline sequence.
1182    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1183        as a starting offset was within the subject string. There is now a new
1184        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1185        negative or greater than the length of the string. In order to test this,
1186        pcretest is extended to allow the setting of negative starting offsets.
1188    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1189        starting offset points to the beginning of a UTF-8 character was
1190        unnecessarily clumsy. I tidied it up.
1192    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1193        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1195    17. Nobody had reported that the --include_dir option, which was added in
1196        release 7.7 should have been called --include-dir (hyphen, not underscore)
1197        for compatibility with GNU grep. I have changed it to --include-dir, but
1198        left --include_dir as an undocumented synonym, and the same for
1199        --exclude-dir, though that is not available in GNU grep, at least as of
1200        release 2.5.4.
1202    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1203        characters from a string of bytes) have been redefined so as not to use
1204        loops, in order to improve performance in some environments. At the same
1205        time, I abstracted some of the common code into auxiliary macros to save
1206        repetition (this should not affect the compiled code).
1208    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1209        compile-time error is now given if \c is not followed by an ASCII
1210        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1211        different, and any byte value is allowed.)
1213    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1214        START_OPTIMIZE option, which is now allowed at compile time - but just
1215        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1216        to pcregrep and other applications that have no direct access to PCRE
1217        options. The new /Y option in pcretest sets this option when calling
1218        pcre_compile().
1220    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1221        back references. Groups containing recursive back references were forced to
1222        be atomic by that change, but in the case of named groups, the amount of
1223        memory required was incorrectly computed, leading to "Failed: internal
1224        error: code overflow". This has been fixed.
1226    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1227        pcretest.c, to avoid build problems in some Borland environments.
1230    Version 8.10 25-Jun-2010
1231  ------------------------  ------------------------
1233  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 9  Version 8.10 03 May-2010 Line 1235  Version 8.10 03 May-2010
1236  2.  (*ACCEPT) was not working when inside an atomic group.  2.  (*ACCEPT) was not working when inside an atomic group.
1238  3.  Inside a character class, \B is treated as a literal by default, but  3.  Inside a character class, \B is treated as a literal by default, but
1239      faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option      faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1240      causes the error). The code is unchanged, but I tidied the documentation.      causes the error). The code is unchanged, but I tidied the documentation.
1242  4.  Inside a character class, PCRE always treated \R and \X as literals,  4.  Inside a character class, PCRE always treated \R and \X as literals,
1243      whereas Perl faults them if its -w option is set. I have changed PCRE so      whereas Perl faults them if its -w option is set. I have changed PCRE so
1244      that it faults them when PCRE_EXTRA is set.      that it faults them when PCRE_EXTRA is set.
1246  5.  Added support for \N, which always matches any character other than  5.  Added support for \N, which always matches any character other than
1247      newline. (It is the same as "." when PCRE_DOTALL is not set.)      newline. (It is the same as "." when PCRE_DOTALL is not set.)
1249  6.  When compiling pcregrep with newer versions of gcc which may have  6.  When compiling pcregrep with newer versions of gcc which may have
1250      FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',      FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1251      declared with attribute warn_unused_result" were given. Just casting the      declared with attribute warn_unused_result" were given. Just casting the
1252      result to (void) does not stop the warnings; a more elaborate fudge is      result to (void) does not stop the warnings; a more elaborate fudge is
1253      needed. I've used a macro to implement this.      needed. I've used a macro to implement this.
1255    7.  Minor change to pcretest.c to avoid a compiler warning.
1257    8.  Added four artifical Unicode properties to help with an option to make
1258        \s etc use properties (see next item). The new properties are: Xan
1259        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1261    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1262        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1263        this option. Modified pcretest to add /W to test this facility. Added
1264        REG_UCP to make it available via the POSIX interface.
1266    10. Added --line-buffered to pcregrep.
1268    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1269        studied, and the match started with a letter with a code point greater than
1270        127 whose first byte was different to the first byte of the other case of
1271        the letter, the other case of this starting letter was not recognized
1272        (#976).
1274    12. If a pattern that was studied started with a repeated Unicode property
1275        test, for example, \p{Nd}+, there was the theoretical possibility of
1276        setting up an incorrect bitmap of starting bytes, but fortunately it could
1277        not have actually happened in practice until change 8 above was made (it
1278        added property types that matched character-matching opcodes).
1280    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1281        possible starting bytes for non-anchored patterns.
1283    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1284        \R, and also a number of cases that involve Unicode properties, both
1285        explicit and implicit when PCRE_UCP is set.
1287    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1288        input, it could crash or give wrong results if characters with values
1289        greater than 0xc0 were present in the subject string. (Detail: it assumed
1290        UTF-8 input when processing these items.)
1292    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1293        size_t is 64-bit (#991).
1295    17. Added a check for running out of memory when PCRE is compiled with
1296        --disable-stack-for-recursion (#990).
1298    18. If the last data line in a file for pcretest does not have a newline on
1299        the end, a newline was missing in the output.
1301    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1302        less than 128) in its various bitmaps. However, there is a facility for
1303        generating tables according to the current locale when PCRE is compiled. It
1304        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1305        characters, are recognized by isspace() and therefore were getting set in
1306        these tables, and indeed these tables seem to approximate to ISO 8859. This
1307        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1308        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1309        which of course cannot start UTF-8 characters. I have changed the code so
1310        that only real ASCII characters (less than 128) and the correct starting
1311        bytes for UTF-8 encodings are set for characters greater than 127 when in
1312        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1313        altogether.)
1315    20. Added the /T option to pcretest so as to be able to run tests with non-
1316        standard character tables, thus making it possible to include the tests
1317        used for 19 above in the standard set of tests.
1319    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1320        reference to a subpattern the other side of a comment that contains an
1321        opening parenthesis caused either an internal compiling error, or a
1322        reference to the wrong subpattern.
1325  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010
# Line 418  Version 7.9 11-Apr-09 Line 1713  Version 7.9 11-Apr-09
1713  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
1714      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
1715      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1716      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1717        8.33.]
1719  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1720      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 661  Version 7.7 07-May-08 Line 1957  Version 7.7 07-May-08
1957      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
1958      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
1959      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
1960      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
1961      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
1962      was subsequently set up correctly.)      was subsequently set up correctly.)

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