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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.5 12-Nov-07  Version 8.34 xx-xxxx-201x
5    --------------------------
6    
7    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
8        executable memory. Patch inspired by Carsten Klein.
9    
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.
17    
18    
19    Version 8.33 28-May-2013
20    --------------------------
21    
22    1.  Added 'U' to some constants that are compared to unsigned integers, to
23        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
24        variables that are added to signed variables, to ensure the result is
25        signed and can be negated.
26    
27    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
28        CMake config files.
29    
30    3.  Revise the creation of config.h.generic so that all boolean macros are
31        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
32        overriding via -D on the command line possible.
33    
34    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
35        to unsigned int is reported to make a quite noticeable speed difference in
36        a specific Windows environment. Testing on Linux did also appear to show
37        some benefit (and it is clearly not harmful). Also fixed the definition of
38        Xop which should be unsigned.
39    
40    5.  Related to (4), changing the definition of the intermediate variable cc
41        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
42        improvements.
43    
44    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
45        unnecessary spaces.
46    
47    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
48        and later.
49    
50    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
51    
52    9.  Optimizing fast_forward_start_bits in JIT.
53    
54    10. Adding support for callouts in JIT, and fixing some issues revealed
55        during this work. Namely:
56    
57        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
58    
59        (b) Minimum length was not checked before the matching is started.
60    
61    11. The value of capture_last that is passed to callouts was incorrect in some
62        cases when there was a capture on one path that was subsequently abandoned
63        after a backtrack. Also, the capture_last value is now reset after a
64        recursion, since all captures are also reset in this case.
65    
66    12. The interpreter no longer returns the "too many substrings" error in the
67        case when an overflowing capture is in a branch that is subsequently
68        abandoned after a backtrack.
69    
70    13. In the pathological case when an offset vector of size 2 is used, pcretest
71        now prints out the matched string after a yield of 0 or 1.
72    
73    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
74        Only supported by the JIT compiler at the moment.
75    
76    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
77    
78    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
79        offset of the starting point of the matching process, provided the offsets
80        vector is large enough.
81    
82    17. The \A escape now records a lookbehind value of 1, though its execution
83        does not actually inspect the previous character. This is to ensure that,
84        in partial multi-segment matching, at least one character from the old
85        segment is retained when a new segment is processed. Otherwise, if there
86        are no lookbehinds in the pattern, \A might match incorrectly at the start
87        of a new segment.
88    
89    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
90    
91    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
92        gives some modest performance improvement in 8-bit mode.
93    
94    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
95        be expressed in certain programming languages using Universal Character
96        Names.
97    
98    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
99        which points out that "non characters" are not "characters that may not
100        appear in Unicode strings" but rather "characters that are reserved for
101        internal use and have only local meaning".
102    
103    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
104        there was a conditional group that depended on an assertion, if the
105        assertion was false, the callout that immediately followed the alternation
106        in the condition was skipped when pcre_exec() was used for matching.
107    
108    23. Allow an explicit callout to be inserted before an assertion that is the
109        condition for a conditional group, for compatibility with automatic
110        callouts, which always insert a callout at this point.
111    
112    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
113        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
114    
115    25. (*PRUNE) is now supported by the JIT compiler.
116    
117    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
118    
119    27. Fix the case where there are two or more SKIPs with arguments that may be
120        ignored.
121    
122    28. (*SKIP) is now supported by the JIT compiler.
123    
124    29. (*THEN) is now supported by the JIT compiler.
125    
126    30. Update RunTest with additional test selector options.
127    
128    31. The way PCRE handles backtracking verbs has been changed in two ways.
129    
130        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
131        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
132        backtracking. In some cases this makes it more Perl-compatible, but Perl's
133        rather obscure rules do not always do the same thing.
134    
135        (2) Previously, backtracking verbs were confined within assertions. This is
136        no longer the case for positive assertions, except for (*ACCEPT). Again,
137        this sometimes improves Perl compatibility, and sometimes does not.
138    
139    32. A number of tests that were in test 2 because Perl did things differently
140        have been moved to test 1, because either Perl or PCRE has changed, and
141        these tests are now compatible.
142    
143    32. Backtracking control verbs are now handled in the same way in JIT and
144        interpreter.
145    
146    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
147        contained a forward subroutine reference caused a compile error.
148    
149    34. Auto-detect and optimize limited repetitions in JIT.
150    
151    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
152        blocking (*UTF) etc.
153    
154    36. In the interpreter, maximizing pattern repetitions for characters and
155        character types now use tail recursion, which reduces stack usage.
156    
157    37. The value of the max lookbehind was not correctly preserved if a compiled
158        and saved regex was reloaded on a host of different endianness.
159    
160    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
161        of the compiled pattern block, expand the flags field from 16 to 32 bits
162        because it was almost full.
163    
164    39. Try madvise first before posix_madvise.
165    
166    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
167        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
168        original change locked out all matches of empty strings. This has been
169        changed so that one match of an empty string per line is recognized.
170        Subsequent searches on the same line (for colouring or for --only-matching,
171        for example) do not recognize empty strings.
172    
173    41. Applied a user patch to fix a number of spelling mistakes in comments.
174    
175    42. Data lines longer than 65536 caused pcretest to crash.
176    
177    43. Clarified the data type for length and startoffset arguments for pcre_exec
178        and pcre_dfa_exec in the function-specific man pages, where they were
179        explicitly stated to be in bytes, never having been updated. I also added
180        some clarification to the pcreapi man page.
181    
182    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
183        a segmentation fault.
184    
185    
186    Version 8.32 30-November-2012
187    -----------------------------
188    
189    1.  Improved JIT compiler optimizations for first character search and single
190        character iterators.
191    
192    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
193        Patch by Daniel Richard G.
194    
195    3.  Single character iterator optimizations in the JIT compiler.
196    
197    4.  Improved JIT compiler optimizations for character ranges.
198    
199    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
200        Reported by Giuseppe D'Angelo.
201    
202    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
203        of a line, was being set incorrectly in cases where .* appeared inside
204        atomic brackets at the start of a pattern, or where there was a subsequent
205        *PRUNE or *SKIP.
206    
207    7.  Improved instruction cache flush for POWER/PowerPC.
208        Patch by Daniel Richard G.
209    
210    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
211        grep:
212    
213        (a) There is now no limit to the number of patterns to be matched.
214    
215        (b) An error is given if a pattern is too long.
216    
217        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
218            are now supported.
219    
220        (d) --exclude-from and --include-from (multiple use) have been added.
221    
222        (e) Exclusions and inclusions now apply to all files and directories, not
223            just to those obtained from scanning a directory recursively.
224    
225        (f) Multiple uses of -f and --file-list are now supported.
226    
227        (g) In a Windows environment, the default for -d has been changed from
228            "read" (the GNU grep default) to "skip", because otherwise the presence
229            of a directory in the file list provokes an error.
230    
231        (h) The documentation has been revised and clarified in places.
232    
233    9.  Improve the matching speed of capturing brackets.
234    
235    10. Changed the meaning of \X so that it now matches a Unicode extended
236        grapheme cluster.
237    
238    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
239        out POSIX threads when JIT support is configured.
240    
241    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
242    
243    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
244        structure could go wrong in environments where size_t is not the same size
245        as int.
246    
247    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
248        set.
249    
250    15. The EBCDIC support had decayed; later updates to the code had included
251        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
252        general tidy up of EBCDIC-related issues, and the documentation was also
253        not quite right. There is now a test that can be run on ASCII systems to
254        check some of the EBCDIC-related things (but is it not a full test).
255    
256    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
257        in a small tidy to the code.
258    
259    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
260    
261    18. If the --only-matching (-o) option in pcregrep is specified multiple
262        times, each one causes appropriate output. For example, -o1 -o2 outputs the
263        substrings matched by the 1st and 2nd capturing parentheses. A separating
264        string can be specified by --om-separator (default empty).
265    
266    19. Improving the first n character searches.
267    
268    20. Turn case lists for horizontal and vertical white space into macros so that
269        they are defined only once.
270    
271    21. This set of changes together give more compatible Unicode case-folding
272        behaviour for characters that have more than one other case when UCP
273        support is available.
274    
275        (a) The Unicode property table now has offsets into a new table of sets of
276            three or more characters that are case-equivalent. The MultiStage2.py
277            script that generates these tables (the pcre_ucd.c file) now scans
278            CaseFolding.txt instead of UnicodeData.txt for character case
279            information.
280    
281        (b) The code for adding characters or ranges of characters to a character
282            class has been abstracted into a generalized function that also handles
283            case-independence. In UTF-mode with UCP support, this uses the new data
284            to handle characters with more than one other case.
285    
286        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
287            whose other case is greater than 256 are now correctly matched
288            caselessly. Previously, the high codepoint matched the low one, but not
289            vice versa.
290    
291        (d) The processing of \h, \H, \v, and \ in character classes now makes use
292            of the new class addition function, using character lists defined as
293            macros alongside the case definitions of 20 above.
294    
295        (e) Caseless back references now work with characters that have more than
296            one other case.
297    
298        (f) General caseless matching of characters with more than one other case
299            is supported.
300    
301    22. Unicode character properties were updated from Unicode 6.2.0
302    
303    23. Improved CMake support under Windows. Patch by Daniel Richard G.
304    
305    24. Add support for 32-bit character strings, and UTF-32
306    
307    25. Major JIT compiler update (code refactoring and bugfixing).
308        Experimental Sparc 32 support is added.
309    
310    26. Applied a modified version of Daniel Richard G's patch to create
311        pcre.h.generic and config.h.generic by "make" instead of in the
312        PrepareRelease script.
313    
314    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
315        pcre_compile.c when checking for a zero character.
316    
317    28. Introducing a native interface for JIT. Through this interface, the compiled
318        machine code can be directly executed. The purpose of this interface is to
319        provide fast pattern matching, so several sanity checks are not performed.
320        However, feature tests are still performed. The new interface provides
321        1.4x speedup compared to the old one.
322    
323    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
324        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
325        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
326    
327    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
328        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
329        the "old" RFC 2279). Instead, it ended up passing a negative length to
330        pcre_exec().
331    
332    31. Add support for GCC's visibility feature to hide internal functions.
333    
334    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
335        "unknown -C option" after outputting 0 or 1.
336    
337    33. There is now support for generating a code coverage report for the test
338        suite in environments where gcc is the compiler and lcov is installed. This
339        is mainly for the benefit of the developers.
340    
341    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
342        unaddressable using valgrind annotations, allowing valgrind to detect
343        invalid memory accesses. This is mainly for the benefit of the developers.
344    
345    25. (*UTF) can now be used to start a pattern in any of the three libraries.
346    
347    26. Give configure error if --enable-cpp but no C++ compiler found.
348    
349    
350    Version 8.31 06-July-2012
351    -------------------------
352    
353    1.  Fixing a wrong JIT test case and some compiler warnings.
354    
355    2.  Removed a bashism from the RunTest script.
356    
357    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
358        to unsigned type, result still unsigned" that was given by an MS compiler
359        on encountering the code "-sizeof(xxx)".
360    
361    4.  Partial matching support is added to the JIT compiler.
362    
363    5.  Fixed several bugs concerned with partial matching of items that consist
364        of more than one character:
365    
366        (a) /^(..)\1/ did not partially match "aba" because checking references was
367            done on an "all or nothing" basis. This also applied to repeated
368            references.
369    
370        (b) \R did not give a hard partial match if \r was found at the end of the
371            subject.
372    
373        (c) \X did not give a hard partial match after matching one or more
374            characters at the end of the subject.
375    
376        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
377            a partial match for the string "\r".
378    
379        (e) When newline was set to CRLF, the metacharacter "." did not recognize
380            a partial match for a CR character at the end of the subject string.
381    
382    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
383        running pcretest, the text "(JIT)" added to the output whenever JIT is
384        actually used to run the match.
385    
386    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
387        or /S+[+] with a digit between 1 and 7.
388    
389    8.  OP_NOT now supports any UTF character not just single-byte ones.
390    
391    9.  (*MARK) control verb is now supported by the JIT compiler.
392    
393    10. The command "./RunTest list" lists the available tests without actually
394        running any of them. (Because I keep forgetting what they all are.)
395    
396    11. Add PCRE_INFO_MAXLOOKBEHIND.
397    
398    12. Applied a (slightly modified) user-supplied patch that improves performance
399        when the heap is used for recursion (compiled with --disable-stack-for-
400        recursion). Instead of malloc and free for each heap frame each time a
401        logical recursion happens, frames are retained on a chain and re-used where
402        possible. This sometimes gives as much as 30% improvement.
403    
404    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
405        call.
406    
407    14. As documented, (*COMMIT) is now confined to within a positive assertion.
408    
409    15. It is now possible to link pcretest with libedit as an alternative to
410        libreadline.
411    
412    16. (*COMMIT) control verb is now supported by the JIT compiler.
413    
414    17. The Unicode data tables have been updated to Unicode 6.1.0.
415    
416    18. Added --file-list option to pcregrep.
417    
418    19. Added binary file support to pcregrep, including the -a, --binary-files,
419        -I, and --text options.
420    
421    20. The madvise function is renamed for posix_madvise for QNX compatibility
422        reasons. Fixed by Giuseppe D'Angelo.
423    
424    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
425    
426    22. Changed the option for creating symbolic links for 16-bit man pages from
427        -s to -sf so that re-installing does not cause issues.
428    
429    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
430    
431    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
432        matches in certain environments (the workspace was not being correctly
433        retained). Also added to pcre_dfa_exec() a simple plausibility check on
434        some of the workspace data at the beginning of a restart.
435    
436    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
437        was not doing so when it should - probably a typo introduced by SVN 528
438        (change 8.10/14).
439    
440    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
441        \w+ when the character tables indicated that \x{c4} was a word character.
442        There were several related cases, all because the tests for doing a table
443        lookup were testing for characters less than 127 instead of 255.
444    
445    27. If a pattern contains capturing parentheses that are not used in a match,
446        their slots in the ovector are set to -1. For those that are higher than
447        any matched groups, this happens at the end of processing. In the case when
448        there were back references that the ovector was too small to contain
449        (causing temporary malloc'd memory to be used during matching), and the
450        highest capturing number was not used, memory off the end of the ovector
451        was incorrectly being set to -1. (It was using the size of the temporary
452        memory instead of the true size.)
453    
454    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
455        ovector size, it uses memory at the end of the block that it has got.
456    
457    29. Check for an overlong MARK name and give an error at compile time. The
458        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
459    
460    30. JIT compiler update.
461    
462    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
463        Rill for the patch.
464    
465    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
466    
467    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
468    
469    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
470        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
471        was enabled.
472    
473    35. Improve JIT code generation for greedy plus quantifier.
474    
475    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
476        1 to "aa" instead of to an empty string. The bug affected repeated groups
477        that could potentially match an empty string.
478    
479    37. Optimizing single character iterators in JIT.
480    
481    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
482        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
483        codepoints that are too big for the mode are faulted, and in a UTF mode,
484        disallowed codepoints are also faulted.
485    
486    39. If PCRE was compiled with UTF support, in three places in the DFA
487        matcher there was code that should only have been obeyed in UTF mode, but
488        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
489        processing when bytes with values greater than 127 were present. In 16-bit
490        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
491        both cases the values are those that cannot be the first data item in a UTF
492        character. The three items that might have provoked this were recursions,
493        possessively repeated groups, and atomic groups.
494    
495    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
496        and pcregrep, because some OS require shared objects to be explicitly
497        passed to ld, causing the link step to fail if they are not.
498    
499    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
500        mode, patterns that started with \h* or \R* might be incorrectly matched.
501    
502    
503    Version 8.30 04-February-2012
504    -----------------------------
505    
506    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
507        name is defined in ctype.h.
508    
509    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
510        only in quite long subpatterns.
511    
512    3.  Removed the function pcre_info(), which has been obsolete and deprecated
513        since it was replaced by pcre_fullinfo() in February 2000.
514    
515    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
516        match a (*MARK), and the match failed at the start of the subject, a
517        reference to memory before the start of the subject could occur. This bug
518        was introduced by fix 17 of release 8.21.
519    
520    5.  A reference to an unset group with zero minimum repetition was giving
521        totally wrong answers (in non-JavaScript-compatibility mode). For example,
522        /(another)?(\1?)test/ matched against "hello world test". This bug was
523        introduced in release 8.13.
524    
525    6.  Add support for 16-bit character strings (a large amount of work involving
526        many changes and refactorings).
527    
528    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
529        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
530        from a file.
531    
532    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
533        rounding is not applied in this particular case).
534    
535    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
536        if they appear, or are escaped, in patterns.
537    
538    10. Get rid of a number of -Wunused-but-set-variable warnings.
539    
540    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
541        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
542        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
543        also returns the mark "x". This bug applied to capturing parentheses,
544        non-capturing parentheses, and atomic parentheses. It also applied to some
545        assertions.
546    
547    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
548        information out of configure.ac instead of relying on pcre.h.generic, which
549        is not stored in the repository.
550    
551    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
552        -lreadline.
553    
554    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
555    
556    15. Applied Graycode's patch to put the top-level frame on the stack rather
557        than the heap when not using the stack for recursion. This gives a
558        performance improvement in many cases when recursion is not deep.
559    
560    16. Experimental code added to "pcretest -C" to output the stack frame size.
561    
562    
563    Version 8.21 12-Dec-2011
564    ------------------------
565    
566    1.  Updating the JIT compiler.
567    
568    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
569        are added as well.
570    
571    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
572        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
573        calling _pcre_jit_exec. Some extra comments are added.
574    
575    4.  (*MARK) settings inside atomic groups that do not contain any capturing
576        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
577        was introduced by change 18 for 8.20.
578    
579    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
580        ECMA-262 standard.
581    
582    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
583        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
584        This bug was probably introduced by change 9 of 8.13.
585    
586    7.  While fixing 6 above, I noticed that a number of other items were being
587        incorrectly rejected as "not fixed length". This arose partly because newer
588        opcodes had not been added to the fixed-length checking code. I have (a)
589        corrected the bug and added tests for these items, and (b) arranged for an
590        error to occur if an unknown opcode is encountered while checking for fixed
591        length instead of just assuming "not fixed length". The items that were
592        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
593        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
594        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
595    
596    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
597        being incorrectly compiled and would have given unpredicatble results.
598    
599    9.  A possessively repeated subpattern with minimum repeat count greater than
600        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
601        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
602        the first (A) could occur when it should not.
603    
604    10. Add a cast and remove a redundant test from the code.
605    
606    11. JIT should use pcre_malloc/pcre_free for allocation.
607    
608    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
609        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
610        is anything other than /usr, -L is still shown).
611    
612    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
613    
614    14. Perl does not support \N without a following name in a [] class; PCRE now
615        also gives an error.
616    
617    15. If a forward reference was repeated with an upper limit of around 2000,
618        it caused the error "internal error: overran compiling workspace". The
619        maximum number of forward references (including repeats) was limited by the
620        internal workspace, and dependent on the LINK_SIZE. The code has been
621        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
622        the default depends on LINK_SIZE. There is a new upper limit (for safety)
623        of around 200,000 forward references. While doing this, I also speeded up
624        the filling in of repeated forward references.
625    
626    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
627        incorrectly expecting the subject to contain another "a" after the start.
628    
629    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
630        in the match, the SKIP should be ignored. This was not happening; instead
631        the SKIP was being treated as NOMATCH. For patterns such as
632        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
633        tested.
634    
635    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
636        now much more compatible with Perl, in particular in cases where the result
637        is a non-match for a non-anchored pattern. For example, if
638        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
639        "m", where previously it did not return a name. A side effect of this
640        change is that for partial matches, the last encountered mark name is
641        returned, as for non matches. A number of tests that were previously not
642        Perl-compatible have been moved into the Perl-compatible test files. The
643        refactoring has had the pleasing side effect of removing one argument from
644        the match() function, thus reducing its stack requirements.
645    
646    19. If the /S+ option was used in pcretest to study a pattern using JIT,
647        subsequent uses of /S (without +) incorrectly behaved like /S+.
648    
649    21. Retrieve executable code size support for the JIT compiler and fixing
650        some warnings.
651    
652    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
653        not work when the shorter character appeared right at the end of the
654        subject string.
655    
656    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
657        systems.
658    
659    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
660        output it when the /M option is used in pcretest.
661    
662    25. The CheckMan script was not being included in the distribution. Also, added
663        an explicit "perl" to run Perl scripts from the PrepareRelease script
664        because this is reportedly needed in Windows.
665    
666    26. If study data was being save in a file and studying had not found a set of
667        "starts with" bytes for the pattern, the data written to the file (though
668        never used) was taken from uninitialized memory and so caused valgrind to
669        complain.
670    
671    27. Updated RunTest.bat as provided by Sheri Pierce.
672    
673    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
674    
675    29. Computation of memory usage for the table of capturing group names was
676        giving an unnecessarily large value.
677    
678    
679    Version 8.20 21-Oct-2011
680    ------------------------
681    
682    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
683        a POSIX class. After further experiments with Perl, which convinced me that
684        Perl has bugs and confusions, a closing square bracket is no longer allowed
685        in a POSIX name. This bug also affected patterns with classes that started
686        with full stops.
687    
688    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
689        captured substring, but while checking the failing first alternative,
690        substring 1 is temporarily captured. If the output vector supplied to
691        pcre_exec() was not big enough for this capture, the yield of the function
692        was still zero ("insufficient space for captured substrings"). This cannot
693        be totally fixed without adding another stack variable, which seems a lot
694        of expense for a edge case. However, I have improved the situation in cases
695        such as /(a)(b)x|abc/ matched against "abc", where the return code
696        indicates that fewer than the maximum number of slots in the ovector have
697        been set.
698    
699    3.  Related to (2) above: when there are more back references in a pattern than
700        slots in the output vector, pcre_exec() uses temporary memory during
701        matching, and copies in the captures as far as possible afterwards. It was
702        using the entire output vector, but this conflicts with the specification
703        that only 2/3 is used for passing back captured substrings. Now it uses
704        only the first 2/3, for compatibility. This is, of course, another edge
705        case.
706    
707    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
708        main code base, and can be used by building with --enable-jit. When this is
709        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
710        runtime --no-jit option is given.
711    
712    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
713        ovector, the return from the function was zero, implying that there were
714        other matches that did not fit. The correct "exactly full" value is now
715        returned.
716    
717    6.  If a subpattern that was called recursively or as a subroutine contained
718        (*PRUNE) or any other control that caused it to give a non-standard return,
719        invalid errors such as "Error -26 (nested recursion at the same subject
720        position)" or even infinite loops could occur.
721    
722    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
723        computing the minimum length on reaching *ACCEPT, and so ended up with the
724        wrong value of 1 rather than 0. Further investigation indicates that
725        computing a minimum subject length in the presence of *ACCEPT is difficult
726        (think back references, subroutine calls), and so I have changed the code
727        so that no minimum is registered for a pattern that contains *ACCEPT.
728    
729    8.  If (*THEN) was present in the first (true) branch of a conditional group,
730        it was not handled as intended. [But see 16 below.]
731    
732    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
733        Sheri Pierce.
734    
735    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
736        the first byte in a match must be "a".
737    
738    11. Change 17 for 8.13 increased the recursion depth for patterns like
739        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
740        pattern contains any instances of (*THEN). If it does not, the old
741        optimizations are restored. It would be nice to do this on a per-group
742        basis, but at the moment that is not feasible.
743    
744    12. In some environments, the output of pcretest -C is CRLF terminated. This
745        broke RunTest's code that checks for the link size. A single white space
746        character after the value is now allowed for.
747    
748    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
749        For "fr", it uses the Windows-specific input and output files.
750    
751    14. If (*THEN) appeared in a group that was called recursively or as a
752        subroutine, it did not work as intended. [But see next item.]
753    
754    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
755        pattern fragments (but not containing any | characters). If A and B are
756        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
757        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
758        D. In other words, Perl considers parentheses that do not contain any |
759        characters to be part of a surrounding alternative, whereas PCRE was
760        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
761        differently. PCRE now behaves in the same way as Perl, except in the case
762        of subroutine/recursion calls such as (?1) which have in any case always
763        been different (but PCRE had them first :-).
764    
765    16. Related to 15 above: Perl does not treat the | in a conditional group as
766        creating alternatives. Such a group is treated in the same way as an
767        ordinary group without any | characters when processing (*THEN). PCRE has
768        been changed to match Perl's behaviour.
769    
770    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
771        RunGrepTest script failed.
772    
773    18. Change 22 for version 13 caused atomic groups to use more stack. This is
774        inevitable for groups that contain captures, but it can lead to a lot of
775        stack use in large patterns. The old behaviour has been restored for atomic
776        groups that do not contain any capturing parentheses.
777    
778    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
779        suppress the check for a minimum subject length at run time. (If it was
780        given to pcre_exec() or pcre_dfa_exec() it did work.)
781    
782    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
783        fail to work when decoding hex characters in data strings in EBCDIC
784        environments.
785    
786    21. It appears that in at least one Mac OS environment, the isxdigit() function
787        is implemented as a macro that evaluates to its argument more than once,
788        contravening the C 90 Standard (I haven't checked a later standard). There
789        was an instance in pcretest which caused it to go wrong when processing
790        \x{...} escapes in subject strings. The has been rewritten to avoid using
791        things like p++ in the argument of isxdigit().
792    
793    
794    Version 8.13 16-Aug-2011
795    ------------------------
796    
797    1.  The Unicode data tables have been updated to Unicode 6.0.0.
798    
799    2.  Two minor typos in pcre_internal.h have been fixed.
800    
801    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
802        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
803        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
804    
805    4.  There were a number of related bugs in the code for matching backrefences
806        caselessly in UTF-8 mode when codes for the characters concerned were
807        different numbers of bytes. For example, U+023A and U+2C65 are an upper
808        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
809        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
810        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
811        2-byte code at the end of the subject (it thought there wasn't enough data
812        left).
813    
814    5.  Comprehensive information about what went wrong is now returned by
815        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
816        as the output vector has at least 2 elements. The offset of the start of
817        the failing character and a reason code are placed in the vector.
818    
819    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
820        now returned is for the first byte of the failing character, instead of the
821        last byte inspected. This is an incompatible change, but I hope it is small
822        enough not to be a problem. It makes the returned offset consistent with
823        pcre_exec() and pcre_dfa_exec().
824    
825    7.  pcretest now gives a text phrase as well as the error number when
826        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
827        failure, the offset and reason code are output.
828    
829    8.  When \R was used with a maximizing quantifier it failed to skip backwards
830        over a \r\n pair if the subsequent match failed. Instead, it just skipped
831        back over a single character (\n). This seems wrong (because it treated the
832        two characters as a single entity when going forwards), conflicts with the
833        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
834        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
835        has been changed.
836    
837    9.  Some internal refactoring has changed the processing so that the handling
838        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
839        time (the PCRE_DOTALL option was changed this way some time ago: version
840        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
841        which was always a bit of a fudge. It also means that there is one less
842        argument for the match() function, which reduces its stack requirements
843        slightly. This change also fixes an incompatibility with Perl: the pattern
844        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
845    
846    10. More internal refactoring has drastically reduced the number of recursive
847        calls to match() for possessively repeated groups such as (abc)++ when
848        using pcre_exec().
849    
850    11. While implementing 10, a number of bugs in the handling of groups were
851        discovered and fixed:
852    
853        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
854        (a|)*(?1) gave a compile-time internal error.
855        ((a|)+)+  did not notice that the outer group could match an empty string.
856        (^a|^)+   was not marked as anchored.
857        (.*a|.*)+ was not marked as matching at start or after a newline.
858    
859    12. Yet more internal refactoring has removed another argument from the match()
860        function. Special calls to this function are now indicated by setting a
861        value in a variable in the "match data" data block.
862    
863    13. Be more explicit in pcre_study() instead of relying on "default" for
864        opcodes that mean there is no starting character; this means that when new
865        ones are added and accidentally left out of pcre_study(), testing should
866        pick them up.
867    
868    14. The -s option of pcretest has been documented for ages as being an old
869        synonym of -m (show memory usage). I have changed it to mean "force study
870        for every regex", that is, assume /S for every regex. This is similar to -i
871        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
872        using it. It makes it easier to run collections of tests with and without
873        study enabled, and thereby test pcre_study() more easily. All the standard
874        tests are now run with and without -s (but some patterns can be marked as
875        "never study" - see 20 below).
876    
877    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
878        restoration of the capturing data to the outer values was not happening
879        correctly.
880    
881    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
882        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
883        pattern had matched an empty string, and so incorrectly returned a no
884        match.
885    
886    17. There was optimizing code for the last branch of non-capturing parentheses,
887        and also for the obeyed branch of a conditional subexpression, which used
888        tail recursion to cut down on stack usage. Unfortunately, now that there is
889        the possibility of (*THEN) occurring in these branches, tail recursion is
890        no longer possible because the return has to be checked for (*THEN). These
891        two optimizations have therefore been removed. [But see 8.20/11 above.]
892    
893    18. If a pattern containing \R was studied, it was assumed that \R always
894        matched two bytes, thus causing the minimum subject length to be
895        incorrectly computed because \R can also match just one byte.
896    
897    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
898        was incorrectly computed.
899    
900    20. If /S is present twice on a test pattern in pcretest input, it now
901        *disables* studying, thereby overriding the use of -s on the command line
902        (see 14 above). This is necessary for one or two tests to keep the output
903        identical in both cases.
904    
905    21. When (*ACCEPT) was used in an assertion that matched an empty string and
906        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
907    
908    22. When an atomic group that contained a capturing parenthesis was
909        successfully matched, but the branch in which it appeared failed, the
910        capturing was not being forgotten if a higher numbered group was later
911        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
912        group 1 to "a", when in fact it should be unset. This applied to multi-
913        branched capturing and non-capturing groups, repeated or not, and also to
914        positive assertions (capturing in negative assertions does not happen
915        in PCRE) and also to nested atomic groups.
916    
917    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
918        subject after a captured substring, to make it easier to tell which of a
919        number of identical substrings has been captured.
920    
921    24. The way atomic groups are processed by pcre_exec() has been changed so that
922        if they are repeated, backtracking one repetition now resets captured
923        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
924        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
925        "aaa". Previously, it would have been "a". As part of this code
926        refactoring, the way recursive calls are handled has also been changed.
927    
928    25. If an assertion condition captured any substrings, they were not passed
929        back unless some other capturing happened later. For example, if
930        (?(?=(a))a) was matched against "a", no capturing was returned.
931    
932    26. When studying a pattern that contained subroutine calls or assertions,
933        the code for finding the minimum length of a possible match was handling
934        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
935        group 1 called group 2 while simultaneously a separate group 2 called group
936        1). A stack overflow occurred in this case. I have fixed this by limiting
937        the recursion depth to 10.
938    
939    27. Updated RunTest.bat in the distribution to the version supplied by Tom
940        Fortmann. This supports explicit test numbers on the command line, and has
941        argument validation and error reporting.
942    
943    28. An instance of \X with an unlimited repeat could fail if at any point the
944        first character it looked at was a mark character.
945    
946    29. Some minor code refactoring concerning Unicode properties and scripts
947        should reduce the stack requirement of match() slightly.
948    
949    30. Added the '=' option to pcretest to check the setting of unused capturing
950        slots at the end of the pattern, which are documented as being -1, but are
951        not included in the return count.
952    
953    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
954        compiled something random. Now it gives a compile-time error (as does
955        Perl).
956    
957    32. A *MARK encountered during the processing of a positive assertion is now
958        recorded and passed back (compatible with Perl).
959    
960    33. If --only-matching or --colour was set on a pcregrep call whose pattern
961        had alternative anchored branches, the search for a second match in a line
962        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
963        matched the line "0102" twice. The same bug affected patterns that started
964        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
965        twice.
966    
967    34. Previously, PCRE did not allow quantification of assertions. However, Perl
968        does, and because of capturing effects, quantifying parenthesized
969        assertions may at times be useful. Quantifiers are now allowed for
970        parenthesized assertions.
971    
972    35. A minor code tidy in pcre_compile() when checking options for \R usage.
973    
974    36. \g was being checked for fancy things in a character class, when it should
975        just be a literal "g".
976    
977    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
978        appearance of a nested POSIX class supersedes an apparent external class.
979        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
980        unescaped square brackets may also appear as part of class names. For
981        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
982        more like Perl. (But see 8.20/1 above.)
983    
984    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
985        was because it thought it was \N{name}, which is not supported).
986    
987    39. Add minix to OS list not supporting the -S option in pcretest.
988    
989    40. PCRE tries to detect cases of infinite recursion at compile time, but it
990        cannot analyze patterns in sufficient detail to catch mutual recursions
991        such as ((?1))((?2)). There is now a runtime test that gives an error if a
992        subgroup is called recursively as a subpattern for a second time at the
993        same position in the subject string. In previous releases this might have
994        been caught by the recursion limit, or it might have run out of stack.
995    
996    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
997        happen only once. PCRE was, however incorrectly giving a compile time error
998        "recursive call could loop indefinitely" because it cannot analyze the
999        pattern in sufficient detail. The compile time test no longer happens when
1000        PCRE is compiling a conditional subpattern, but actual runaway loops are
1001        now caught at runtime (see 40 above).
1002    
1003    42. It seems that Perl allows any characters other than a closing parenthesis
1004        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1005        has been changed to be the same.
1006    
1007    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1008        as not to get warnings when autogen.sh is called. Also changed
1009        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1010    
1011    44. To help people who use pcregrep to scan files containing exceedingly long
1012        lines, the following changes have been made:
1013    
1014        (a) The default value of the buffer size parameter has been increased from
1015            8K to 20K. (The actual buffer used is three times this size.)
1016    
1017        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1018            PCRE is built.
1019    
1020        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1021            to be set at run time.
1022    
1023        (d) Numerical values in pcregrep options can be followed by K or M, for
1024            example --buffer-size=50K.
1025    
1026        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1027            given and the return code is set to 2.
1028    
1029    45. Add a pointer to the latest mark to the callout data block.
1030    
1031    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1032        partial match of an empty string instead of no match. This was specific to
1033        the use of ".".
1034    
1035    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1036        complete match instead of a partial match. This bug was dependent on both
1037        the PCRE_UTF8 and PCRE_DOTALL options being set.
1038    
1039    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1040        starting byte set, because \b was not being ignored.
1041    
1042    
1043    Version 8.12 15-Jan-2011
1044    ------------------------
1045    
1046    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1047        checks for such things as part of the documentation building process.
1048    
1049    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1050        --match-limit and --recursion-limit options (added for 8.11). In
1051        particular, this made one of the standard tests fail. (The integer value
1052        went into the wrong half of a long int.)
1053    
1054    3.  If the --colour option was given to pcregrep with -v (invert match), it
1055        did strange things, either producing crazy output, or crashing. It should,
1056        of course, ignore a request for colour when reporting lines that do not
1057        match.
1058    
1059    4.  Another pcregrep bug caused similar problems if --colour was specified with
1060        -M (multiline) and the pattern match finished with a line ending.
1061    
1062    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1063        matched in multiline mode, the following line was shown as part of the
1064        match. This seems wrong, so I have changed it.
1065    
1066    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1067        the check for further matches in the same line (so they could be coloured)
1068        to overrun the end of the current line. If another match was found, it was
1069        incorrectly shown (and then shown again when found in the next line).
1070    
1071    7.  If pcregrep was compiled under Windows, there was a reference to the
1072        function pcregrep_exit() before it was defined. I am assuming this was
1073        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1074        reported by a user. I've moved the definition above the reference.
1075    
1076    
1077    Version 8.11 10-Dec-2010
1078    ------------------------
1079    
1080    1.  (*THEN) was not working properly if there were untried alternatives prior
1081        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1082        backtracked to try for "b" instead of moving to the next alternative branch
1083        at the same level (in this case, to look for "c"). The Perl documentation
1084        is clear that when (*THEN) is backtracked onto, it goes to the "next
1085        alternative in the innermost enclosing group".
1086    
1087    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1088        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1089        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1090        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1091        (*THEN).
1092    
1093    3.  If \s appeared in a character class, it removed the VT character from
1094        the class, even if it had been included by some previous item, for example
1095        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1096        of \s, but is part of the POSIX "space" class.)
1097    
1098    4.  A partial match never returns an empty string (because you can always
1099        match an empty string at the end of the subject); however the checking for
1100        an empty string was starting at the "start of match" point. This has been
1101        changed to the "earliest inspected character" point, because the returned
1102        data for a partial match starts at this character. This means that, for
1103        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1104        (previously it gave "no match").
1105    
1106    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1107        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1108        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1109        has an implication that the given string is incomplete (because a partial
1110        match is preferred over a full match). For this reason, these items now
1111        give a partial match in this situation. [Aside: previously, the one case
1112        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1113        match rather than a full match, which was wrong by the old rules, but is
1114        now correct.]
1115    
1116    6.  There was a bug in the handling of #-introduced comments, recognized when
1117        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1118        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1119        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1120        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1121        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1122        places in pcre_compile().
1123    
1124    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1125        comments when looking ahead for named forward references to subpatterns,
1126        the only newline sequence it recognized was NL. It now handles newlines
1127        according to the set newline convention.
1128    
1129    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1130        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1131        cater for a lack of strerror(). These oversights have been fixed.
1132    
1133    9.  Added --match-limit and --recursion-limit to pcregrep.
1134    
1135    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1136    
1137    11. When the -o option was used, pcregrep was setting a return code of 1, even
1138        when matches were found, and --line-buffered was not being honoured.
1139    
1140    12. Added an optional parentheses number to the -o and --only-matching options
1141        of pcregrep.
1142    
1143    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1144        can match an empty string. The code to do it in pcretest and pcredemo
1145        needed fixing:
1146    
1147        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1148            only one byte after an empty string match just before CRLF (this case
1149            just got forgotten; "any" and "anycrlf" were OK).
1150    
1151        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1152            mode when an empty string match preceded an ASCII character followed by
1153            a non-ASCII character. (The code for advancing by one character rather
1154            than one byte was nonsense.)
1155    
1156        (c) The pcredemo.c sample program did not have any code at all to handle
1157            the cases when CRLF is a valid newline sequence.
1158    
1159    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1160        as a starting offset was within the subject string. There is now a new
1161        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1162        negative or greater than the length of the string. In order to test this,
1163        pcretest is extended to allow the setting of negative starting offsets.
1164    
1165    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1166        starting offset points to the beginning of a UTF-8 character was
1167        unnecessarily clumsy. I tidied it up.
1168    
1169    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1170        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1171    
1172    17. Nobody had reported that the --include_dir option, which was added in
1173        release 7.7 should have been called --include-dir (hyphen, not underscore)
1174        for compatibility with GNU grep. I have changed it to --include-dir, but
1175        left --include_dir as an undocumented synonym, and the same for
1176        --exclude-dir, though that is not available in GNU grep, at least as of
1177        release 2.5.4.
1178    
1179    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1180        characters from a string of bytes) have been redefined so as not to use
1181        loops, in order to improve performance in some environments. At the same
1182        time, I abstracted some of the common code into auxiliary macros to save
1183        repetition (this should not affect the compiled code).
1184    
1185    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1186        compile-time error is now given if \c is not followed by an ASCII
1187        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1188        different, and any byte value is allowed.)
1189    
1190    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1191        START_OPTIMIZE option, which is now allowed at compile time - but just
1192        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1193        to pcregrep and other applications that have no direct access to PCRE
1194        options. The new /Y option in pcretest sets this option when calling
1195        pcre_compile().
1196    
1197    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1198        back references. Groups containing recursive back references were forced to
1199        be atomic by that change, but in the case of named groups, the amount of
1200        memory required was incorrectly computed, leading to "Failed: internal
1201        error: code overflow". This has been fixed.
1202    
1203    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1204        pcretest.c, to avoid build problems in some Borland environments.
1205    
1206    
1207    Version 8.10 25-Jun-2010
1208    ------------------------
1209    
1210    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1211        THEN.
1212    
1213    2.  (*ACCEPT) was not working when inside an atomic group.
1214    
1215    3.  Inside a character class, \B is treated as a literal by default, but
1216        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1217        causes the error). The code is unchanged, but I tidied the documentation.
1218    
1219    4.  Inside a character class, PCRE always treated \R and \X as literals,
1220        whereas Perl faults them if its -w option is set. I have changed PCRE so
1221        that it faults them when PCRE_EXTRA is set.
1222    
1223    5.  Added support for \N, which always matches any character other than
1224        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1225    
1226    6.  When compiling pcregrep with newer versions of gcc which may have
1227        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1228        declared with attribute warn_unused_result" were given. Just casting the
1229        result to (void) does not stop the warnings; a more elaborate fudge is
1230        needed. I've used a macro to implement this.
1231    
1232    7.  Minor change to pcretest.c to avoid a compiler warning.
1233    
1234    8.  Added four artifical Unicode properties to help with an option to make
1235        \s etc use properties (see next item). The new properties are: Xan
1236        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1237    
1238    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1239        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1240        this option. Modified pcretest to add /W to test this facility. Added
1241        REG_UCP to make it available via the POSIX interface.
1242    
1243    10. Added --line-buffered to pcregrep.
1244    
1245    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1246        studied, and the match started with a letter with a code point greater than
1247        127 whose first byte was different to the first byte of the other case of
1248        the letter, the other case of this starting letter was not recognized
1249        (#976).
1250    
1251    12. If a pattern that was studied started with a repeated Unicode property
1252        test, for example, \p{Nd}+, there was the theoretical possibility of
1253        setting up an incorrect bitmap of starting bytes, but fortunately it could
1254        not have actually happened in practice until change 8 above was made (it
1255        added property types that matched character-matching opcodes).
1256    
1257    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1258        possible starting bytes for non-anchored patterns.
1259    
1260    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1261        \R, and also a number of cases that involve Unicode properties, both
1262        explicit and implicit when PCRE_UCP is set.
1263    
1264    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1265        input, it could crash or give wrong results if characters with values
1266        greater than 0xc0 were present in the subject string. (Detail: it assumed
1267        UTF-8 input when processing these items.)
1268    
1269    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1270        size_t is 64-bit (#991).
1271    
1272    17. Added a check for running out of memory when PCRE is compiled with
1273        --disable-stack-for-recursion (#990).
1274    
1275    18. If the last data line in a file for pcretest does not have a newline on
1276        the end, a newline was missing in the output.
1277    
1278    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1279        less than 128) in its various bitmaps. However, there is a facility for
1280        generating tables according to the current locale when PCRE is compiled. It
1281        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1282        characters, are recognized by isspace() and therefore were getting set in
1283        these tables, and indeed these tables seem to approximate to ISO 8859. This
1284        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1285        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1286        which of course cannot start UTF-8 characters. I have changed the code so
1287        that only real ASCII characters (less than 128) and the correct starting
1288        bytes for UTF-8 encodings are set for characters greater than 127 when in
1289        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1290        altogether.)
1291    
1292    20. Added the /T option to pcretest so as to be able to run tests with non-
1293        standard character tables, thus making it possible to include the tests
1294        used for 19 above in the standard set of tests.
1295    
1296    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1297        reference to a subpattern the other side of a comment that contains an
1298        opening parenthesis caused either an internal compiling error, or a
1299        reference to the wrong subpattern.
1300    
1301    
1302    Version 8.02 19-Mar-2010
1303    ------------------------
1304    
1305    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1306    
1307    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1308        configured.
1309    
1310    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1311        original author of that file, following a query about its status.
1312    
1313    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1314        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1315    
1316    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1317        quantifier applied to a forward-referencing subroutine call, could compile
1318        incorrect code or give the error "internal error: previously-checked
1319        referenced subpattern not found".
1320    
1321    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1322        variables to point to external functions. For these systems, therefore,
1323        pcre_malloc etc. are now initialized to local functions that call the
1324        relevant global functions.
1325    
1326    7.  There were two entries missing in the vectors called coptable and poptable
1327        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1328        I've fixed the data, and added a kludgy way of testing at compile time that
1329        the lengths are correct (equal to the number of opcodes).
1330    
1331    8.  Following on from 7, I added a similar kludge to check the length of the
1332        eint vector in pcreposix.c.
1333    
1334    9.  Error texts for pcre_compile() are held as one long string to avoid too
1335        much relocation at load time. To find a text, the string is searched,
1336        counting zeros. There was no check for running off the end of the string,
1337        which could happen if a new error number was added without updating the
1338        string.
1339    
1340    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1341    
1342    11. \K was not working if it appeared in an atomic group or in a group that
1343        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1344        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1345        the assertion is positive, but not if it is negative.
1346    
1347    12. Change 11 fortuitously reduced the size of the stack frame used in the
1348        "match()" function of pcre_exec.c by one pointer. Forthcoming
1349        implementation of support for (*MARK) will need an extra pointer on the
1350        stack; I have reserved it now, so that the stack frame size does not
1351        decrease.
1352    
1353    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1354        item in branch that calls a recursion is a subroutine call - as in the
1355        second branch in the above example - was incorrectly given the compile-
1356        time error "recursive call could loop indefinitely" because pcre_compile()
1357        was not correctly checking the subroutine for matching a non-empty string.
1358    
1359    14. The checks for overrunning compiling workspace could trigger after an
1360        overrun had occurred. This is a "should never occur" error, but it can be
1361        triggered by pathological patterns such as hundreds of nested parentheses.
1362        The checks now trigger 100 bytes before the end of the workspace.
1363    
1364    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1365    
1366    
1367    Version 8.01 19-Jan-2010
1368    ------------------------
1369    
1370    1.  If a pattern contained a conditional subpattern with only one branch (in
1371        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1372        computed the wrong minimum data length (which is of course zero for such
1373        subpatterns). This could cause incorrect "no match" results.
1374    
1375    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1376        the pattern is reset in the first branch, pcre_compile() failed with
1377        "internal error: code overflow at offset...". This happened only when
1378        the reset was to the original external option setting. (An optimization
1379        abstracts leading options settings into an external setting, which was the
1380        cause of this.)
1381    
1382    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1383        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1384        assertion pattern did not match (meaning that the assertion was true), it
1385        was incorrectly treated as false if the SKIP had been reached during the
1386        matching. This also applied to assertions used as conditions.
1387    
1388    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1389        assertion subpattern, including such a pattern used as a condition,
1390        unpredictable results occurred, instead of the error return
1391        PCRE_ERROR_DFA_UITEM.
1392    
1393    5.  The C++ GlobalReplace function was not working like Perl for the special
1394        situation when an empty string is matched. It now does the fancy magic
1395        stuff that is necessary.
1396    
1397    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1398        removed. (These were left over from very, very early versions of PCRE.)
1399    
1400    7.  Some cosmetic changes to the code to make life easier when compiling it
1401        as part of something else:
1402    
1403        (a) Change DEBUG to PCRE_DEBUG.
1404    
1405        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1406            called "current" as "current_branch", to prevent a collision with the
1407            Linux macro when compiled as a kernel module.
1408    
1409        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1410            prevent a collision with the Linux macro when compiled as a kernel
1411            module.
1412    
1413    8.  In pcre_compile() there are some checks for integer overflows that used to
1414        cast potentially large values to (double). This has been changed to that
1415        when building, a check for int64_t is made, and if it is found, it is used
1416        instead, thus avoiding the use of floating point arithmetic. (There is no
1417        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1418        double.
1419    
1420    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1421        2005 (difference between two addresses compared to an unsigned value).
1422    
1423    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1424        custom one, because of the following reported problem in Windows:
1425    
1426          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1427              under Win32.
1428          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1429              therefore missing the function definition.
1430          - The compiler thus generates a "C" signature for the test function.
1431          - The linker fails to find the "C" function.
1432          - PCRE fails to configure if asked to do so against libbz2.
1433    
1434    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1435        messages were output:
1436    
1437          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1438          rerunning libtoolize, to keep the correct libtool macros in-tree.
1439          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1440    
1441        I have done both of these things.
1442    
1443    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1444        most of the time, it *can* run out if it is given a pattern that contains a
1445        runaway infinite recursion. I updated the discussion in the pcrestack man
1446        page.
1447    
1448    13. Now that we have gone to the x.xx style of version numbers, the minor
1449        version may start with zero. Using 08 or 09 is a bad idea because users
1450        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1451        interpreted as invalid octal numbers. I've updated the previous comment in
1452        configure.ac, and also added a check that gives an error if 08 or 09 are
1453        used.
1454    
1455    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1456        causing partial matching to fail when the end of the subject matched \W
1457        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1458    
1459    15. There were some discrepancies between the declarations in pcre_internal.h
1460        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1461        their definitions. The declarations used "const uschar *" and the
1462        definitions used USPTR. Even though USPTR is normally defined as "const
1463        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1464        reported that: "This difference in casting confuses some C++ compilers, for
1465        example, SunCC recognizes above declarations as different functions and
1466        generates broken code for hbpcre." I have changed the declarations to use
1467        USPTR.
1468    
1469    16. GNU libtool is named differently on some systems. The autogen.sh script now
1470        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1471        (FreeBSD).
1472    
1473    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1474        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1475        comment: "Figure out how to create a longlong from a string: strtoll and
1476        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1477        instance, but it only takes 2 args instead of 3!"
1478    
1479    18. A subtle bug concerned with back references has been fixed by a change of
1480        specification, with a corresponding code fix. A pattern such as
1481        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1482        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1483        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1484        same bug. Such groups have to be quantified to be useful, or contained
1485        inside another quantified group. (If there's no repetition, the reference
1486        can never match.) The problem arises because, having left the group and
1487        moved on to the rest of the pattern, a later failure that backtracks into
1488        the group uses the captured value from the final iteration of the group
1489        rather than the correct earlier one. I have fixed this in PCRE by forcing
1490        any group that contains a reference to itself to be an atomic group; that
1491        is, there cannot be any backtracking into it once it has completed. This is
1492        similar to recursive and subroutine calls.
1493    
1494    
1495    Version 8.00 19-Oct-09
1496    ----------------------
1497    
1498    1.  The table for translating pcre_compile() error codes into POSIX error codes
1499        was out-of-date, and there was no check on the pcre_compile() error code
1500        being within the table. This could lead to an OK return being given in
1501        error.
1502    
1503    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1504        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1505        in a Windows environment.
1506    
1507    3.  The pcregrep --count option prints the count for each file even when it is
1508        zero, as does GNU grep. However, pcregrep was also printing all files when
1509        --files-with-matches was added. Now, when both options are given, it prints
1510        counts only for those files that have at least one match. (GNU grep just
1511        prints the file name in this circumstance, but including the count seems
1512        more useful - otherwise, why use --count?) Also ensured that the
1513        combination -clh just lists non-zero counts, with no names.
1514    
1515    4.  The long form of the pcregrep -F option was incorrectly implemented as
1516        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1517        but it seems right to fix it, and I didn't think it was worth preserving
1518        the old behaviour.
1519    
1520    5.  The command line items --regex=pattern and --regexp=pattern were not
1521        recognized by pcregrep, which required --regex pattern or --regexp pattern
1522        (with a space rather than an '='). The man page documented the '=' forms,
1523        which are compatible with GNU grep; these now work.
1524    
1525    6.  No libpcreposix.pc file was created for pkg-config; there was just
1526        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1527    
1528    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1529        when UCP support is not needed, by modifying the Python script that
1530        generates it from Unicode data files. This should not matter if the module
1531        is correctly used as a library, but I received one complaint about 50K of
1532        unwanted data. My guess is that the person linked everything into his
1533        program rather than using a library. Anyway, it does no harm.
1534    
1535    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1536        was a minimum greater than 1 for a wide character in a possessive
1537        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1538        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1539        character. Chaos in the form of incorrect output or a compiling loop could
1540        result.
1541    
1542    9.  The restrictions on what a pattern can contain when partial matching is
1543        requested for pcre_exec() have been removed. All patterns can now be
1544        partially matched by this function. In addition, if there are at least two
1545        slots in the offset vector, the offset of the earliest inspected character
1546        for the match and the offset of the end of the subject are set in them when
1547        PCRE_ERROR_PARTIAL is returned.
1548    
1549    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1550        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1551        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1552        and may be more useful for multi-segment matching.
1553    
1554    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1555        used to be given if ever the end of the subject was reached; now it is
1556        given only if matching could not proceed because another character was
1557        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1558        string "Z", which now yields "no match" instead of "partial match". In the
1559        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1560        final character ended with (*FAIL).
1561    
1562    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1563        if the pattern had a "must contain" character that was already found in the
1564        earlier partial match, unless partial matching was again requested. For
1565        example, with the pattern /dog.(body)?/, the "must contain" character is
1566        "g". If the first part-match was for the string "dog", restarting with
1567        "sbody" failed. This bug has been fixed.
1568    
1569    13. The string returned by pcre_dfa_exec() after a partial match has been
1570        changed so that it starts at the first inspected character rather than the
1571        first character of the match. This makes a difference only if the pattern
1572        starts with a lookbehind assertion or \b or \B (\K is not supported by
1573        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1574        matching functions compatible, and I think it's the right thing to do.
1575    
1576    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1577        so that the demonstration program is easily available in environments where
1578        PCRE has not been installed from source.
1579    
1580    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1581        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1582        library.
1583    
1584    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1585        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1586        is not the first non-POSIX option to be added. Clearly some people find
1587        these options useful.
1588    
1589    17. If a caller to the POSIX matching function regexec() passes a non-zero
1590        value for nmatch with a NULL value for pmatch, the value of
1591        nmatch is forced to zero.
1592    
1593    18. RunGrepTest did not have a test for the availability of the -u option of
1594        the diff command, as RunTest does. It now checks in the same way as
1595        RunTest, and also checks for the -b option.
1596    
1597    19. If an odd number of negated classes containing just a single character
1598        interposed, within parentheses, between a forward reference to a named
1599        subpattern and the definition of the subpattern, compilation crashed with
1600        an internal error, complaining that it could not find the referenced
1601        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1602        [The bug was that it was starting one character too far in when skipping
1603        over the character class, thus treating the ] as data rather than
1604        terminating the class. This meant it could skip too much.]
1605    
1606    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1607        /g option in pcretest when the pattern contains \K, which makes it possible
1608        to have an empty string match not at the start, even when the pattern is
1609        anchored. Updated pcretest and pcredemo to use this option.
1610    
1611    21. If the maximum number of capturing subpatterns in a recursion was greater
1612        than the maximum at the outer level, the higher number was returned, but
1613        with unset values at the outer level. The correct (outer level) value is
1614        now given.
1615    
1616    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1617        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1618        make it do so. The string so far is captured, making this feature
1619        compatible with Perl.
1620    
1621    23. The tests have been re-organized, adding tests 11 and 12, to make it
1622        possible to check the Perl 5.10 features against Perl 5.10.
1623    
1624    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1625        pattern matches a fixed length string. PCRE did not allow this; now it
1626        does. Neither allows recursion.
1627    
1628    25. I finally figured out how to implement a request to provide the minimum
1629        length of subject string that was needed in order to match a given pattern.
1630        (It was back references and recursion that I had previously got hung up
1631        on.) This code has now been added to pcre_study(); it finds a lower bound
1632        to the length of subject needed. It is not necessarily the greatest lower
1633        bound, but using it to avoid searching strings that are too short does give
1634        some useful speed-ups. The value is available to calling programs via
1635        pcre_fullinfo().
1636    
1637    26. While implementing 25, I discovered to my embarrassment that pcretest had
1638        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1639        study optimizations had never been tested with that matching function.
1640        Oops. What is worse, even when it was passed study data, there was a bug in
1641        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1642        were also very few tests of studied patterns with pcre_dfa_exec().
1643    
1644    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1645        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1646        on the other side of the coin, they are no longer allowed to have different
1647        names, because these cannot be distinguished in PCRE, and this has caused
1648        confusion. (This is a difference from Perl.)
1649    
1650    28. When duplicate subpattern names are present (necessarily with different
1651        numbers, as required by 27 above), and a test is made by name in a
1652        conditional pattern, either for a subpattern having been matched, or for
1653        recursion in such a pattern, all the associated numbered subpatterns are
1654        tested, and the overall condition is true if the condition is true for any
1655        one of them. This is the way Perl works, and is also more like the way
1656        testing by number works.
1657    
1658    
1659    Version 7.9 11-Apr-09
1660    ---------------------
1661    
1662    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1663        (pcretest), all targets were linked against these libraries. This included
1664        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1665        libraries. This caused unwanted dependencies to be created. This problem
1666        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1667        pcretest is linked with readline.
1668    
1669    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1670        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1671        moved outside it again, because FALSE and TRUE are already defined in AIX,
1672        but BOOL is not.
1673    
1674    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1675        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1676    
1677    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1678        hyphens) following file names and line numbers when outputting matching
1679        lines. This is not true; no spaces are inserted. I have also clarified the
1680        wording for the --colour (or --color) option.
1681    
1682    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1683        was not coloured; this is different to GNU grep, so I have changed it to be
1684        the same.
1685    
1686    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1687        each matching line was coloured. Now it goes on to look for further matches
1688        of any of the test patterns, which is the same behaviour as GNU grep.
1689    
1690    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1691        doesn't make sense to accept an empty string match in pcregrep, so I have
1692        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1693        seems to be how GNU grep behaves. [But see later change 40 for release
1694        8.33.]
1695    
1696    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1697        start or after a newline", because the conditional assertion was not being
1698        correctly handled. The rule now is that both the assertion and what follows
1699        in the first alternative must satisfy the test.
1700    
1701    9.  If auto-callout was enabled in a pattern with a conditional group whose
1702        condition was an assertion, PCRE could crash during matching, both with
1703        pcre_exec() and pcre_dfa_exec().
1704    
1705    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1706        used for matching.
1707    
1708    11. Unicode property support in character classes was not working for
1709        characters (bytes) greater than 127 when not in UTF-8 mode.
1710    
1711    12. Added the -M command line option to pcretest.
1712    
1713    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1714    
1715    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1716    
1717    16. Added comments and documentation about mis-use of no_arg in the C++
1718        wrapper.
1719    
1720    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1721        from Martin Jerabek that uses macro names for all relevant character and
1722        string constants.
1723    
1724    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1725        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1726        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1727        these, but not everybody uses configure.
1728    
1729    19. A conditional group that had only one branch was not being correctly
1730        recognized as an item that could match an empty string. This meant that an
1731        enclosing group might also not be so recognized, causing infinite looping
1732        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1733        with the subject "ab", where knowledge that the repeated group can match
1734        nothing is needed in order to break the loop.
1735    
1736    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1737        exec(), but without supplying a callout function, matching went wrong.
1738    
1739    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1740        leak if the size of the offset vector was greater than 30. When the vector
1741        is smaller, the saved offsets during recursion go onto a local stack
1742        vector, but for larger vectors malloc() is used. It was failing to free
1743        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1744        error, in fact).
1745    
1746    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1747        heapframe that is used only when UTF-8 support is enabled. This caused no
1748        problem, but was untidy.
1749    
1750    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1751        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1752        included within another project.
1753    
1754    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1755        slightly modified by me:
1756    
1757          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1758              not building pcregrep.
1759    
1760          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1761              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1762    
1763    25. Forward references, both numeric and by name, in patterns that made use of
1764        duplicate group numbers, could behave incorrectly or give incorrect errors,
1765        because when scanning forward to find the reference group, PCRE was not
1766        taking into account the duplicate group numbers. A pattern such as
1767        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1768    
1769    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1770        the feature of a custom pointer more persuasive (as requested by a user).
1771    
1772    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1773        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1774        pre-defined.
1775    
1776    28. Added support for (*UTF8) at the start of a pattern.
1777    
1778    29. Arrange for flags added by the "release type" setting in CMake to be shown
1779        in the configuration summary.
1780    
1781    
1782    Version 7.8 05-Sep-08
1783    ---------------------
1784    
1785    1.  Replaced UCP searching code with optimized version as implemented for Ad
1786        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1787        stage table and inline lookup instead of a function, giving speed ups of 2
1788        to 5 times on some simple patterns that I tested. Permission was given to
1789        distribute the MultiStage2.py script that generates the tables (it's not in
1790        the tarball, but is in the Subversion repository).
1791    
1792    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1793        scripts.
1794    
1795    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1796        a group with a zero qualifier. The result of the study could be incorrect,
1797        or the function might crash, depending on the pattern.
1798    
1799    4.  Caseless matching was not working for non-ASCII characters in back
1800        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1801        It now works when Unicode Property Support is available.
1802    
1803    5.  In pcretest, an escape such as \x{de} in the data was always generating
1804        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1805        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1806        truncation.
1807    
1808    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1809    
1810    7.  Added two (int) casts to pcregrep when printing the difference of two
1811        pointers, in case they are 64-bit values.
1812    
1813    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1814        test 2 if it fails.
1815    
1816    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1817        and a #define of that name to empty if it is not externally set. This is to
1818        allow users of MSVC to set it if necessary.
1819    
1820    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1821        the convenience functions in the pcre_get.c source file.
1822    
1823    11. An option change at the start of a pattern that had top-level alternatives
1824        could cause overwriting and/or a crash. This command provoked a crash in
1825        some environments:
1826    
1827          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1828    
1829        This potential security problem was recorded as CVE-2008-2371.
1830    
1831    12. For a pattern where the match had to start at the beginning or immediately
1832        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1833        pcre_dfa_exec() could read past the end of the passed subject if there was
1834        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1835        pcretest so that it places the subject at the end of its malloc-ed buffer.
1836    
1837    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1838        exec() might read past the end of the data buffer in UTF-8 mode.
1839    
1840    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1841        the data contained the byte 0x85 as part of a UTF-8 character within its
1842        first line. This applied both to normal and DFA matching.
1843    
1844    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1845        /^[^d]*?$/8 failed to match "abc".
1846    
1847    16. Added a missing copyright notice to pcrecpp_internal.h.
1848    
1849    17. Make it more clear in the documentation that values returned from
1850        pcre_exec() in ovector are byte offsets, not character counts.
1851    
1852    18. Tidied a few places to stop certain compilers from issuing warnings.
1853    
1854    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1855        supplied by Stefan Weber. I made a further small update for 7.8 because
1856        there is a change of source arrangements: the pcre_searchfuncs.c module is
1857        replaced by pcre_ucd.c.
1858    
1859    
1860    Version 7.7 07-May-08
1861    ---------------------
1862    
1863    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1864        a string to a long long, pretend we don't even have a long long." This is
1865        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1866    
1867    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1868        pre-7.6 versions, which defined a global no_arg variable instead of putting
1869        it in the RE class. (See also #8 below.)
1870    
1871    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1872        Lopes.
1873    
1874    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1875    
1876        (1) The include/exclude patterns were being applied to the whole pathnames
1877            of files, instead of just to the final components.
1878    
1879        (2) If there was more than one level of directory, the subdirectories were
1880            skipped unless they satisfied the include/exclude conditions. This is
1881            inconsistent with GNU grep (and could even be seen as contrary to the
1882            pcregrep specification - which I improved to make it absolutely clear).
1883            The action now is always to scan all levels of directory, and just
1884            apply the include/exclude patterns to regular files.
1885    
1886    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1887        --exclude_dir in the tests to avoid scanning .svn directories.
1888    
1889    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1890        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1891        doesn't support NULs in patterns.
1892    
1893    7.  Added some missing "const"s to declarations of static tables in
1894        pcre_compile.c and pcre_dfa_exec.c.
1895    
1896    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1897        caused by fix #2  above. (Subsequently also a second patch to fix the
1898        first patch. And a third patch - this was a messy problem.)
1899    
1900    9.  Applied Craig's patch to remove the use of push_back().
1901    
1902    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1903        matching function regexec().
1904    
1905    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1906        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1907        references. PCRE supports relative numbers with this syntax (I don't think
1908        Oniguruma does).
1909    
1910    12. Previously, a group with a zero repeat such as (...){0} was completely
1911        omitted from the compiled regex. However, this means that if the group
1912        was called as a subroutine from elsewhere in the pattern, things went wrong
1913        (an internal error was given). Such groups are now left in the compiled
1914        pattern, with a new opcode that causes them to be skipped at execution
1915        time.
1916    
1917    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1918        to the way PCRE behaves:
1919    
1920        (a) A lone ] character is dis-allowed (Perl treats it as data).
1921    
1922        (b) A back reference to an unmatched subpattern matches an empty string
1923            (Perl fails the current match path).
1924    
1925        (c) A data ] in a character class must be notated as \] because if the
1926            first data character in a class is ], it defines an empty class. (In
1927            Perl it is not possible to have an empty class.) The empty class []
1928            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1929            The negative empty class [^] matches any one character, independently
1930            of the DOTALL setting.
1931    
1932    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1933        non-existent subpattern following a character class starting with ']' and
1934        containing () gave an internal compiling error instead of "reference to
1935        non-existent subpattern". Fortunately, when the pattern did exist, the
1936        compiled code was correct. (When scanning forwards to check for the
1937        existence of the subpattern, it was treating the data ']' as terminating
1938        the class, so got the count wrong. When actually compiling, the reference
1939        was subsequently set up correctly.)
1940    
1941    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1942        it was being rejected as not supported by pcre_dfa_exec(), even though
1943        other assertions are supported. I have made pcre_dfa_exec() support
1944        (*FAIL).
1945    
1946    16. The implementation of 13c above involved the invention of a new opcode,
1947        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1948        cannot be changed at match time, I realized I could make a small
1949        improvement to matching performance by compiling OP_ALLANY instead of
1950        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1951        on the OP_ANY path.
1952    
1953    17. Compiling pcretest on Windows with readline support failed without the
1954        following two fixes: (1) Make the unistd.h include conditional on
1955        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1956    
1957    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1958        ncurses library to be included for pcretest when ReadLine support is
1959        requested, but also to allow for it to be overridden. This patch came from
1960        Daniel Bergström.
1961    
1962    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1963        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1964        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1965        spotting this.
1966    
1967    
1968    Version 7.6 28-Jan-08
1969    ---------------------
1970    
1971    1.  A character class containing a very large number of characters with
1972        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1973        overflow.
1974    
1975    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1976        HAVE_LONG_LONG is not defined.
1977    
1978    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1979        bring them up to date and include new features. This patch includes:
1980    
1981        - Fixed PH's badly added libz and libbz2 support.
1982        - Fixed a problem with static linking.
1983        - Added pcredemo. [But later removed - see 7 below.]
1984        - Fixed dftables problem and added an option.
1985        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1986            HAVE_LONG_LONG.
1987        - Added readline support for pcretest.
1988        - Added an listing of the option settings after cmake has run.
1989    
1990    4.  A user submitted a patch to Makefile that makes it easy to create
1991        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1992        Makefile.am that cause it to include this special target, without
1993        affecting anything else. Note that the same mingw target plus all
1994        the other distribution libraries and programs are now supported
1995        when configuring with CMake (see 6 below) instead of with
1996        Configure/Make.
1997    
1998    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1999        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
2000        exported in the Windows port". It has not yet been confirmed that the patch
2001        solves the problem, but it does no harm.
2002    
2003    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
2004        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
2005        with CMake, and also correct the comment about stack recursion.
2006    
2007    7.  Remove the automatic building of pcredemo from the ./configure system and
2008        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
2009        of a program that users should build themselves after PCRE is installed, so
2010        building it automatically is not really right. What is more, it gave
2011        trouble in some build environments.
2012    
2013    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
2014    
2015    
2016    Version 7.5 10-Jan-08
2017  ---------------------  ---------------------
2018    
2019  1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'  1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
2020      values in parens when parsing an RE using the C++ wrapper."      values in parens when parsing an RE using the C++ wrapper."
2021    
2022  2.  Negative specials like \S did not work in character classes in UTF-8 mode.  2.  Negative specials like \S did not work in character classes in UTF-8 mode.
2023      Characters greater than 255 were excluded from the class instead of being      Characters greater than 255 were excluded from the class instead of being
2024      included.      included.
2025    
2026  3.  The same bug as (2) above applied to negated POSIX classes such as  3.  The same bug as (2) above applied to negated POSIX classes such as
2027      [:^space:].      [:^space:].
2028    
2029  4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it  4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
2030      defined or documented. It seems to have been a typo for PCRE_STATIC, so      defined or documented. It seems to have been a typo for PCRE_STATIC, so
2031      I have changed it.      I have changed it.
2032    
2033  5.  The construct (?&) was not diagnosed as a syntax error (it referenced the  5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
2034      first named subpattern) and a construct such as (?&a) would reference the      first named subpattern) and a construct such as (?&a) would reference the
2035      first named subpattern whose name started with "a" (in other words, the      first named subpattern whose name started with "a" (in other words, the
2036      length check was missing). Both these problems are fixed. "Subpattern name      length check was missing). Both these problems are fixed. "Subpattern name
2037      expected" is now given for (?&) (a zero-length name), and this patch also      expected" is now given for (?&) (a zero-length name), and this patch also
2038      makes it give the same error for \k'' (previously it complained that that      makes it give the same error for \k'' (previously it complained that that
2039      was a reference to a non-existent subpattern).      was a reference to a non-existent subpattern).
2040    
2041  6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;  6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
2042      this is right because (?- can be followed by option settings as well as by      this is right because (?- can be followed by option settings as well as by
2043      digits. I have, however, made the messages clearer.      digits. I have, however, made the messages clearer.
2044    
2045  7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns  7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
2046      than the number used in the conditional) now cause a compile-time error.      than the number used in the conditional) now cause a compile-time error.
2047      This is actually not compatible with Perl, which accepts such patterns, but      This is actually not compatible with Perl, which accepts such patterns, but
2048      treats the conditional as always being FALSE (as PCRE used to), but it      treats the conditional as always being FALSE (as PCRE used to), but it
2049      seems to me that giving a diagnostic is better.      seems to me that giving a diagnostic is better.
2050    
2051  8.  Change "alphameric" to the more common word "alphanumeric" in comments  8.  Change "alphameric" to the more common word "alphanumeric" in comments
2052      and messages.      and messages.
2053    
2054  9.  Fix two occurrences of "backslash" in comments that should have been  9.  Fix two occurrences of "backslash" in comments that should have been
2055      "backspace".      "backspace".
2056    
2057  10. Remove two redundant lines of code that can never be obeyed (their function  10. Remove two redundant lines of code that can never be obeyed (their function
2058      was moved elsewhere).      was moved elsewhere).
2059    
2060  11. The program that makes PCRE's Unicode character property table had a bug  11. The program that makes PCRE's Unicode character property table had a bug
2061      which caused it to generate incorrect table entries for sequences of      which caused it to generate incorrect table entries for sequences of
2062      characters that have the same character type, but are in different scripts.      characters that have the same character type, but are in different scripts.
2063      It amalgamated them into a single range, with the script of the first of      It amalgamated them into a single range, with the script of the first of
2064      them. In other words, some characters were in the wrong script. There were      them. In other words, some characters were in the wrong script. There were
2065      thirteen such cases, affecting characters in the following ranges:      thirteen such cases, affecting characters in the following ranges:
2066    
2067        U+002b0 - U+002c1        U+002b0 - U+002c1
2068        U+0060c - U+0060d        U+0060c - U+0060d
2069        U+0061e - U+00612        U+0061e - U+00612
2070        U+0064b - U+0065e        U+0064b - U+0065e
2071        U+0074d - U+0076d        U+0074d - U+0076d
2072        U+01800 - U+01805        U+01800 - U+01805
# Line 66  Version 7.5 12-Nov-07 Line 2078  Version 7.5 12-Nov-07
2078        U+0fb46 - U+0fbb1        U+0fb46 - U+0fbb1
2079        U+10450 - U+1049d        U+10450 - U+1049d
2080    
2081    12. The -o option (show only the matching part of a line) for pcregrep was not
2082        compatible with GNU grep in that, if there was more than one match in a
2083        line, it showed only the first of them. It now behaves in the same way as
2084        GNU grep.
2085    
2086    13. If the -o and -v options were combined for pcregrep, it printed a blank
2087        line for every non-matching line. GNU grep prints nothing, and pcregrep now
2088        does the same. The return code can be used to tell if there were any
2089        non-matching lines.
2090    
2091    14. Added --file-offsets and --line-offsets to pcregrep.
2092    
2093    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
2094        infinitely looping recursion. The bug was that positive lookaheads were not
2095        being skipped when checking for a possible empty match (negative lookaheads
2096        and both kinds of lookbehind were skipped).
2097    
2098    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
2099        inclusion of <windows.h> to before rather than after the definition of
2100        INVALID_FILE_ATTRIBUTES (patch from David Byron).
2101    
2102    17. Specifying a possessive quantifier with a specific limit for a Unicode
2103        character property caused pcre_compile() to compile bad code, which led at
2104        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
2105        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
2106        caused the error; without that there was no problem.
2107    
2108    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
2109    
2110    19. Added --enable-pcretest-libreadline.
2111    
2112    20. In pcrecpp.cc, the variable 'count' was incremented twice in
2113        RE::GlobalReplace(). As a result, the number of replacements returned was
2114        double what it should be. I removed one of the increments, but Craig sent a
2115        later patch that removed the other one (the right fix) and added unit tests
2116        that check the return values (which was not done before).
2117    
2118    21. Several CMake things:
2119    
2120        (1) Arranged that, when cmake is used on Unix, the libraries end up with
2121            the names libpcre and libpcreposix, not just pcre and pcreposix.
2122    
2123        (2) The above change means that pcretest and pcregrep are now correctly
2124            linked with the newly-built libraries, not previously installed ones.
2125    
2126        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
2127    
2128    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
2129        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
2130        UTF-8 newline character). The key issue is that the pattern starts .*;
2131        this means that the match must be either at the beginning, or after a
2132        newline. The bug was in the code for advancing after a failed match and
2133        checking that the new position followed a newline. It was not taking
2134        account of UTF-8 characters correctly.
2135    
2136    23. PCRE was behaving differently from Perl in the way it recognized POSIX
2137        character classes. PCRE was not treating the sequence [:...:] as a
2138        character class unless the ... were all letters. Perl, however, seems to
2139        allow any characters between [: and :], though of course it rejects as
2140        unknown any "names" that contain non-letters, because all the known class
2141        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
2142        for example, whereas PCRE did not - it did not recognize a POSIX character
2143        class. This seemed a bit dangerous, so the code has been changed to be
2144        closer to Perl. The behaviour is not identical to Perl, because PCRE will
2145        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
2146        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
2147        Perl does, and where it didn't before.
2148    
2149    24. Rewrite so as to remove the single use of %n from pcregrep because in some
2150        Windows environments %n is disabled by default.
2151    
2152    
2153  Version 7.4 21-Sep-07  Version 7.4 21-Sep-07
2154  ---------------------  ---------------------

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