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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.11 10-Oct-2010  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    3.  Make a small performance improvement in strlen16() and strlen32() in
19        pcretest.
20    
21    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
22        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
23        these cases). There was also one in pcretest.c.
24    
25    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
26    
27    6.  In UTF mode, the code for checking whether a group could match an empty
28        string (which is used for indefinitely repeated groups to allow for
29        breaking an infinite loop) was broken when the group contained a repeated
30        negated single-character class with a character that occupied more than one
31        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
32        UTF-8 mode). The effect was undefined: the group might or might not be
33        deemed as matching an empty string, or the program might have crashed.
34    
35    7.  The code for checking whether a group could match an empty string was not
36        recognizing that \h, \H, \v, \V, and \R must match a character.
37    
38    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
39        an empty string. If it can, pcretest shows this in its information output.
40    
41    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
42        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
43        matched by pcre_exec() without using JIT:
44    
45        (a) If the rest of the pattern did not match after a maximal run of
46            grapheme clusters, the code for backing up to try with fewer of them
47            did not always back up over a full grapheme when characters that do not
48            have the modifier quality were involved, e.g. Hangul syllables.
49    
50        (b) If the match point in a subject started with modifier character, and
51            there was no match, the code could incorrectly back up beyond the match
52            point, and potentially beyond the first character in the subject,
53            leading to a segfault or an incorrect match result.
54    
55    10. A conditional group with an assertion condition could lead to PCRE
56        recording an incorrect first data item for a match if no other first data
57        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
58        first data item, and therefore matched "ca" after "c" instead of at the
59        start.
60    
61    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
62        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
63    
64    12. The source of pcregrep now includes z/OS-specific code so that it can be
65        compiled for z/OS as part of the special z/OS distribution.
66    
67    13. Added the -T and -TM options to pcretest.
68    
69    14. The code in pcre_compile.c for creating the table of named capturing groups
70        has been refactored. Instead of creating the table dynamically during the
71        actual compiling pass, the information is remembered during the pre-compile
72        pass (on the stack unless there are more than 20 named groups, in which
73        case malloc() is used) and the whole table is created before the actual
74        compile happens. This has simplified the code (it is now nearly 150 lines
75        shorter) and prepared the way for better handling of references to groups
76        with duplicate names.
77    
78    15. A back reference to a named subpattern when there is more than one of the
79        same name now checks them in the order in which they appear in the pattern.
80        The first one that is set is used for the reference. Previously only the
81        first one was inspected. This change makes PCRE more compatible with Perl.
82    
83    16. Unicode character properties were updated from Unicode 6.3.0.
84    
85    17. The compile-time code for auto-possessification has been refactored, based
86        on a patch by Zoltan Herczeg. It now happens after instead of during
87        compilation. The code is cleaner, and more cases are handled. The option
88        PCRE_NO_AUTO_POSSESSIFY is added for testing purposes, and the -O and /O
89        options in pcretest are provided to set it.
90    
91    18. The character VT has been added to the set of characters that match \s and
92        are generally treated as white space, following this same change in Perl
93        5.18. There is now no difference between "Perl space" and "POSIX space".
94    
95    19. The code for checking named groups as conditions, either for being set or
96        for being recursed, has been refactored (this is related to 14 and 15
97        above). Processing unduplicated named groups should now be as fast at
98        numerical groups, and processing duplicated groups should be faster than
99        before.
100    
101    20. Two patches to the CMake build system, by Alexander Barkov:
102    
103          (1) Replace the "source" command by "." in CMakeLists.txt because
104              "source" is a bash-ism.
105    
106          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
107              without these the CMake build does not work on Solaris.
108    
109    21. Perl has changed its handling of \8 and \9. If there is no previously
110        encountered capturing group of those numbers, they are treated as the
111        literal characters 8 and 9 instead of a binary zero followed by the
112        literals. PCRE now does the same.
113    
114    22. Following Perl, added \o{} to specify codepoints in octal, making it
115        possible to specify values greater than 0777 and also making them
116        unambiguous.
117    
118    23. Perl now gives an error for missing closing braces after \x{... instead of
119        treating the string as literal. PCRE now does the same.
120    
121    24. RunTest used to grumble if an inappropriate test was selected explicitly,
122        but just skip it when running all tests. This make it awkward to run ranges
123        of tests when one of them was inappropriate. Now it just skips any
124        inappropriate tests, as it always did when running all tests.
125    
126    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
127        character types such as \d or \w, too many callouts were inserted, and the
128        data that they returned was rubbish.
129    
130    26. In UCP mode, \s was not matching two of the characters that Perl matches,
131        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
132        were matched by \h. The code has now been refactored so that the lists of
133        the horizontal and vertical whitespace characters used for \h and \v (which
134        are defined only in one place) are now also used for \s.
135    
136    27. Add JIT support for the 64 bit TileGX architecture.
137        Patch by Jiong Wang (Tilera Corporation).
138    
139    28. Possessive quantifiers for classes (both explicit and automatically
140        generated) now use special opcodes instead of wrapping in ONCE brackets.
141    
142    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
143        (because it's meaningless), this was not happening when PCRE_CASELESS was
144        set. Not wrong, but inefficient.
145    
146    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
147        properties for \w, \d, etc) is present in a test regex. Otherwise if the
148        test contains no characters greater than 255, Perl doesn't realise it
149        should be using Unicode semantics.
150    
151    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
152        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
153        does in Unicode mode.
154    
155    32. Added the "forbid" facility to pcretest so that putting tests into the
156        wrong test files can sometimes be quickly detected.
157    
158    
159    Version 8.33 28-May-2013
160    ------------------------
161    
162    1.  Added 'U' to some constants that are compared to unsigned integers, to
163        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
164        variables that are added to signed variables, to ensure the result is
165        signed and can be negated.
166    
167    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
168        CMake config files.
169    
170    3.  Revise the creation of config.h.generic so that all boolean macros are
171        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
172        overriding via -D on the command line possible.
173    
174    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
175        to unsigned int is reported to make a quite noticeable speed difference in
176        a specific Windows environment. Testing on Linux did also appear to show
177        some benefit (and it is clearly not harmful). Also fixed the definition of
178        Xop which should be unsigned.
179    
180    5.  Related to (4), changing the definition of the intermediate variable cc
181        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
182        improvements.
183    
184    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
185        unnecessary spaces.
186    
187    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
188        and later.
189    
190    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
191    
192    9.  Optimizing fast_forward_start_bits in JIT.
193    
194    10. Adding support for callouts in JIT, and fixing some issues revealed
195        during this work. Namely:
196    
197        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
198    
199        (b) Minimum length was not checked before the matching is started.
200    
201    11. The value of capture_last that is passed to callouts was incorrect in some
202        cases when there was a capture on one path that was subsequently abandoned
203        after a backtrack. Also, the capture_last value is now reset after a
204        recursion, since all captures are also reset in this case.
205    
206    12. The interpreter no longer returns the "too many substrings" error in the
207        case when an overflowing capture is in a branch that is subsequently
208        abandoned after a backtrack.
209    
210    13. In the pathological case when an offset vector of size 2 is used, pcretest
211        now prints out the matched string after a yield of 0 or 1.
212    
213    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
214        Only supported by the JIT compiler at the moment.
215    
216    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
217    
218    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
219        offset of the starting point of the matching process, provided the offsets
220        vector is large enough.
221    
222    17. The \A escape now records a lookbehind value of 1, though its execution
223        does not actually inspect the previous character. This is to ensure that,
224        in partial multi-segment matching, at least one character from the old
225        segment is retained when a new segment is processed. Otherwise, if there
226        are no lookbehinds in the pattern, \A might match incorrectly at the start
227        of a new segment.
228    
229    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
230    
231    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
232        gives some modest performance improvement in 8-bit mode.
233    
234    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
235        be expressed in certain programming languages using Universal Character
236        Names.
237    
238    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
239        which points out that "non characters" are not "characters that may not
240        appear in Unicode strings" but rather "characters that are reserved for
241        internal use and have only local meaning".
242    
243    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
244        there was a conditional group that depended on an assertion, if the
245        assertion was false, the callout that immediately followed the alternation
246        in the condition was skipped when pcre_exec() was used for matching.
247    
248    23. Allow an explicit callout to be inserted before an assertion that is the
249        condition for a conditional group, for compatibility with automatic
250        callouts, which always insert a callout at this point.
251    
252    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
253        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
254    
255    25. (*PRUNE) is now supported by the JIT compiler.
256    
257    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
258    
259    27. Fix the case where there are two or more SKIPs with arguments that may be
260        ignored.
261    
262    28. (*SKIP) is now supported by the JIT compiler.
263    
264    29. (*THEN) is now supported by the JIT compiler.
265    
266    30. Update RunTest with additional test selector options.
267    
268    31. The way PCRE handles backtracking verbs has been changed in two ways.
269    
270        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
271        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
272        backtracking. In some cases this makes it more Perl-compatible, but Perl's
273        rather obscure rules do not always do the same thing.
274    
275        (2) Previously, backtracking verbs were confined within assertions. This is
276        no longer the case for positive assertions, except for (*ACCEPT). Again,
277        this sometimes improves Perl compatibility, and sometimes does not.
278    
279    32. A number of tests that were in test 2 because Perl did things differently
280        have been moved to test 1, because either Perl or PCRE has changed, and
281        these tests are now compatible.
282    
283    32. Backtracking control verbs are now handled in the same way in JIT and
284        interpreter.
285    
286    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
287        contained a forward subroutine reference caused a compile error.
288    
289    34. Auto-detect and optimize limited repetitions in JIT.
290    
291    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
292        blocking (*UTF) etc.
293    
294    36. In the interpreter, maximizing pattern repetitions for characters and
295        character types now use tail recursion, which reduces stack usage.
296    
297    37. The value of the max lookbehind was not correctly preserved if a compiled
298        and saved regex was reloaded on a host of different endianness.
299    
300    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
301        of the compiled pattern block, expand the flags field from 16 to 32 bits
302        because it was almost full.
303    
304    39. Try madvise first before posix_madvise.
305    
306    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
307        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
308        original change locked out all matches of empty strings. This has been
309        changed so that one match of an empty string per line is recognized.
310        Subsequent searches on the same line (for colouring or for --only-matching,
311        for example) do not recognize empty strings.
312    
313    41. Applied a user patch to fix a number of spelling mistakes in comments.
314    
315    42. Data lines longer than 65536 caused pcretest to crash.
316    
317    43. Clarified the data type for length and startoffset arguments for pcre_exec
318        and pcre_dfa_exec in the function-specific man pages, where they were
319        explicitly stated to be in bytes, never having been updated. I also added
320        some clarification to the pcreapi man page.
321    
322    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
323        a segmentation fault.
324    
325    
326    Version 8.32 30-November-2012
327    -----------------------------
328    
329    1.  Improved JIT compiler optimizations for first character search and single
330        character iterators.
331    
332    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
333        Patch by Daniel Richard G.
334    
335    3.  Single character iterator optimizations in the JIT compiler.
336    
337    4.  Improved JIT compiler optimizations for character ranges.
338    
339    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
340        Reported by Giuseppe D'Angelo.
341    
342    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
343        of a line, was being set incorrectly in cases where .* appeared inside
344        atomic brackets at the start of a pattern, or where there was a subsequent
345        *PRUNE or *SKIP.
346    
347    7.  Improved instruction cache flush for POWER/PowerPC.
348        Patch by Daniel Richard G.
349    
350    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
351        grep:
352    
353        (a) There is now no limit to the number of patterns to be matched.
354    
355        (b) An error is given if a pattern is too long.
356    
357        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
358            are now supported.
359    
360        (d) --exclude-from and --include-from (multiple use) have been added.
361    
362        (e) Exclusions and inclusions now apply to all files and directories, not
363            just to those obtained from scanning a directory recursively.
364    
365        (f) Multiple uses of -f and --file-list are now supported.
366    
367        (g) In a Windows environment, the default for -d has been changed from
368            "read" (the GNU grep default) to "skip", because otherwise the presence
369            of a directory in the file list provokes an error.
370    
371        (h) The documentation has been revised and clarified in places.
372    
373    9.  Improve the matching speed of capturing brackets.
374    
375    10. Changed the meaning of \X so that it now matches a Unicode extended
376        grapheme cluster.
377    
378    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
379        out POSIX threads when JIT support is configured.
380    
381    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
382    
383    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
384        structure could go wrong in environments where size_t is not the same size
385        as int.
386    
387    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
388        set.
389    
390    15. The EBCDIC support had decayed; later updates to the code had included
391        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
392        general tidy up of EBCDIC-related issues, and the documentation was also
393        not quite right. There is now a test that can be run on ASCII systems to
394        check some of the EBCDIC-related things (but is it not a full test).
395    
396    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
397        in a small tidy to the code.
398    
399    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
400    
401    18. If the --only-matching (-o) option in pcregrep is specified multiple
402        times, each one causes appropriate output. For example, -o1 -o2 outputs the
403        substrings matched by the 1st and 2nd capturing parentheses. A separating
404        string can be specified by --om-separator (default empty).
405    
406    19. Improving the first n character searches.
407    
408    20. Turn case lists for horizontal and vertical white space into macros so that
409        they are defined only once.
410    
411    21. This set of changes together give more compatible Unicode case-folding
412        behaviour for characters that have more than one other case when UCP
413        support is available.
414    
415        (a) The Unicode property table now has offsets into a new table of sets of
416            three or more characters that are case-equivalent. The MultiStage2.py
417            script that generates these tables (the pcre_ucd.c file) now scans
418            CaseFolding.txt instead of UnicodeData.txt for character case
419            information.
420    
421        (b) The code for adding characters or ranges of characters to a character
422            class has been abstracted into a generalized function that also handles
423            case-independence. In UTF-mode with UCP support, this uses the new data
424            to handle characters with more than one other case.
425    
426        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
427            whose other case is greater than 256 are now correctly matched
428            caselessly. Previously, the high codepoint matched the low one, but not
429            vice versa.
430    
431        (d) The processing of \h, \H, \v, and \ in character classes now makes use
432            of the new class addition function, using character lists defined as
433            macros alongside the case definitions of 20 above.
434    
435        (e) Caseless back references now work with characters that have more than
436            one other case.
437    
438        (f) General caseless matching of characters with more than one other case
439            is supported.
440    
441    22. Unicode character properties were updated from Unicode 6.2.0
442    
443    23. Improved CMake support under Windows. Patch by Daniel Richard G.
444    
445    24. Add support for 32-bit character strings, and UTF-32
446    
447    25. Major JIT compiler update (code refactoring and bugfixing).
448        Experimental Sparc 32 support is added.
449    
450    26. Applied a modified version of Daniel Richard G's patch to create
451        pcre.h.generic and config.h.generic by "make" instead of in the
452        PrepareRelease script.
453    
454    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
455        pcre_compile.c when checking for a zero character.
456    
457    28. Introducing a native interface for JIT. Through this interface, the compiled
458        machine code can be directly executed. The purpose of this interface is to
459        provide fast pattern matching, so several sanity checks are not performed.
460        However, feature tests are still performed. The new interface provides
461        1.4x speedup compared to the old one.
462    
463    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
464        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
465        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
466    
467    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
468        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
469        the "old" RFC 2279). Instead, it ended up passing a negative length to
470        pcre_exec().
471    
472    31. Add support for GCC's visibility feature to hide internal functions.
473    
474    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
475        "unknown -C option" after outputting 0 or 1.
476    
477    33. There is now support for generating a code coverage report for the test
478        suite in environments where gcc is the compiler and lcov is installed. This
479        is mainly for the benefit of the developers.
480    
481    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
482        unaddressable using valgrind annotations, allowing valgrind to detect
483        invalid memory accesses. This is mainly for the benefit of the developers.
484    
485    25. (*UTF) can now be used to start a pattern in any of the three libraries.
486    
487    26. Give configure error if --enable-cpp but no C++ compiler found.
488    
489    
490    Version 8.31 06-July-2012
491    -------------------------
492    
493    1.  Fixing a wrong JIT test case and some compiler warnings.
494    
495    2.  Removed a bashism from the RunTest script.
496    
497    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
498        to unsigned type, result still unsigned" that was given by an MS compiler
499        on encountering the code "-sizeof(xxx)".
500    
501    4.  Partial matching support is added to the JIT compiler.
502    
503    5.  Fixed several bugs concerned with partial matching of items that consist
504        of more than one character:
505    
506        (a) /^(..)\1/ did not partially match "aba" because checking references was
507            done on an "all or nothing" basis. This also applied to repeated
508            references.
509    
510        (b) \R did not give a hard partial match if \r was found at the end of the
511            subject.
512    
513        (c) \X did not give a hard partial match after matching one or more
514            characters at the end of the subject.
515    
516        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
517            a partial match for the string "\r".
518    
519        (e) When newline was set to CRLF, the metacharacter "." did not recognize
520            a partial match for a CR character at the end of the subject string.
521    
522    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
523        running pcretest, the text "(JIT)" added to the output whenever JIT is
524        actually used to run the match.
525    
526    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
527        or /S+[+] with a digit between 1 and 7.
528    
529    8.  OP_NOT now supports any UTF character not just single-byte ones.
530    
531    9.  (*MARK) control verb is now supported by the JIT compiler.
532    
533    10. The command "./RunTest list" lists the available tests without actually
534        running any of them. (Because I keep forgetting what they all are.)
535    
536    11. Add PCRE_INFO_MAXLOOKBEHIND.
537    
538    12. Applied a (slightly modified) user-supplied patch that improves performance
539        when the heap is used for recursion (compiled with --disable-stack-for-
540        recursion). Instead of malloc and free for each heap frame each time a
541        logical recursion happens, frames are retained on a chain and re-used where
542        possible. This sometimes gives as much as 30% improvement.
543    
544    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
545        call.
546    
547    14. As documented, (*COMMIT) is now confined to within a positive assertion.
548    
549    15. It is now possible to link pcretest with libedit as an alternative to
550        libreadline.
551    
552    16. (*COMMIT) control verb is now supported by the JIT compiler.
553    
554    17. The Unicode data tables have been updated to Unicode 6.1.0.
555    
556    18. Added --file-list option to pcregrep.
557    
558    19. Added binary file support to pcregrep, including the -a, --binary-files,
559        -I, and --text options.
560    
561    20. The madvise function is renamed for posix_madvise for QNX compatibility
562        reasons. Fixed by Giuseppe D'Angelo.
563    
564    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
565    
566    22. Changed the option for creating symbolic links for 16-bit man pages from
567        -s to -sf so that re-installing does not cause issues.
568    
569    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
570    
571    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
572        matches in certain environments (the workspace was not being correctly
573        retained). Also added to pcre_dfa_exec() a simple plausibility check on
574        some of the workspace data at the beginning of a restart.
575    
576    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
577        was not doing so when it should - probably a typo introduced by SVN 528
578        (change 8.10/14).
579    
580    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
581        \w+ when the character tables indicated that \x{c4} was a word character.
582        There were several related cases, all because the tests for doing a table
583        lookup were testing for characters less than 127 instead of 255.
584    
585    27. If a pattern contains capturing parentheses that are not used in a match,
586        their slots in the ovector are set to -1. For those that are higher than
587        any matched groups, this happens at the end of processing. In the case when
588        there were back references that the ovector was too small to contain
589        (causing temporary malloc'd memory to be used during matching), and the
590        highest capturing number was not used, memory off the end of the ovector
591        was incorrectly being set to -1. (It was using the size of the temporary
592        memory instead of the true size.)
593    
594    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
595        ovector size, it uses memory at the end of the block that it has got.
596    
597    29. Check for an overlong MARK name and give an error at compile time. The
598        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
599    
600    30. JIT compiler update.
601    
602    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
603        Rill for the patch.
604    
605    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
606    
607    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
608    
609    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
610        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
611        was enabled.
612    
613    35. Improve JIT code generation for greedy plus quantifier.
614    
615    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
616        1 to "aa" instead of to an empty string. The bug affected repeated groups
617        that could potentially match an empty string.
618    
619    37. Optimizing single character iterators in JIT.
620    
621    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
622        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
623        codepoints that are too big for the mode are faulted, and in a UTF mode,
624        disallowed codepoints are also faulted.
625    
626    39. If PCRE was compiled with UTF support, in three places in the DFA
627        matcher there was code that should only have been obeyed in UTF mode, but
628        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
629        processing when bytes with values greater than 127 were present. In 16-bit
630        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
631        both cases the values are those that cannot be the first data item in a UTF
632        character. The three items that might have provoked this were recursions,
633        possessively repeated groups, and atomic groups.
634    
635    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
636        and pcregrep, because some OS require shared objects to be explicitly
637        passed to ld, causing the link step to fail if they are not.
638    
639    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
640        mode, patterns that started with \h* or \R* might be incorrectly matched.
641    
642    
643    Version 8.30 04-February-2012
644    -----------------------------
645    
646    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
647        name is defined in ctype.h.
648    
649    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
650        only in quite long subpatterns.
651    
652    3.  Removed the function pcre_info(), which has been obsolete and deprecated
653        since it was replaced by pcre_fullinfo() in February 2000.
654    
655    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
656        match a (*MARK), and the match failed at the start of the subject, a
657        reference to memory before the start of the subject could occur. This bug
658        was introduced by fix 17 of release 8.21.
659    
660    5.  A reference to an unset group with zero minimum repetition was giving
661        totally wrong answers (in non-JavaScript-compatibility mode). For example,
662        /(another)?(\1?)test/ matched against "hello world test". This bug was
663        introduced in release 8.13.
664    
665    6.  Add support for 16-bit character strings (a large amount of work involving
666        many changes and refactorings).
667    
668    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
669        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
670        from a file.
671    
672    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
673        rounding is not applied in this particular case).
674    
675    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
676        if they appear, or are escaped, in patterns.
677    
678    10. Get rid of a number of -Wunused-but-set-variable warnings.
679    
680    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
681        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
682        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
683        also returns the mark "x". This bug applied to capturing parentheses,
684        non-capturing parentheses, and atomic parentheses. It also applied to some
685        assertions.
686    
687    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
688        information out of configure.ac instead of relying on pcre.h.generic, which
689        is not stored in the repository.
690    
691    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
692        -lreadline.
693    
694    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
695    
696    15. Applied Graycode's patch to put the top-level frame on the stack rather
697        than the heap when not using the stack for recursion. This gives a
698        performance improvement in many cases when recursion is not deep.
699    
700    16. Experimental code added to "pcretest -C" to output the stack frame size.
701    
702    
703    Version 8.21 12-Dec-2011
704    ------------------------
705    
706    1.  Updating the JIT compiler.
707    
708    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
709        are added as well.
710    
711    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
712        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
713        calling _pcre_jit_exec. Some extra comments are added.
714    
715    4.  (*MARK) settings inside atomic groups that do not contain any capturing
716        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
717        was introduced by change 18 for 8.20.
718    
719    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
720        ECMA-262 standard.
721    
722    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
723        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
724        This bug was probably introduced by change 9 of 8.13.
725    
726    7.  While fixing 6 above, I noticed that a number of other items were being
727        incorrectly rejected as "not fixed length". This arose partly because newer
728        opcodes had not been added to the fixed-length checking code. I have (a)
729        corrected the bug and added tests for these items, and (b) arranged for an
730        error to occur if an unknown opcode is encountered while checking for fixed
731        length instead of just assuming "not fixed length". The items that were
732        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
733        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
734        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
735    
736    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
737        being incorrectly compiled and would have given unpredicatble results.
738    
739    9.  A possessively repeated subpattern with minimum repeat count greater than
740        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
741        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
742        the first (A) could occur when it should not.
743    
744    10. Add a cast and remove a redundant test from the code.
745    
746    11. JIT should use pcre_malloc/pcre_free for allocation.
747    
748    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
749        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
750        is anything other than /usr, -L is still shown).
751    
752    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
753    
754    14. Perl does not support \N without a following name in a [] class; PCRE now
755        also gives an error.
756    
757    15. If a forward reference was repeated with an upper limit of around 2000,
758        it caused the error "internal error: overran compiling workspace". The
759        maximum number of forward references (including repeats) was limited by the
760        internal workspace, and dependent on the LINK_SIZE. The code has been
761        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
762        the default depends on LINK_SIZE. There is a new upper limit (for safety)
763        of around 200,000 forward references. While doing this, I also speeded up
764        the filling in of repeated forward references.
765    
766    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
767        incorrectly expecting the subject to contain another "a" after the start.
768    
769    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
770        in the match, the SKIP should be ignored. This was not happening; instead
771        the SKIP was being treated as NOMATCH. For patterns such as
772        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
773        tested.
774    
775    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
776        now much more compatible with Perl, in particular in cases where the result
777        is a non-match for a non-anchored pattern. For example, if
778        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
779        "m", where previously it did not return a name. A side effect of this
780        change is that for partial matches, the last encountered mark name is
781        returned, as for non matches. A number of tests that were previously not
782        Perl-compatible have been moved into the Perl-compatible test files. The
783        refactoring has had the pleasing side effect of removing one argument from
784        the match() function, thus reducing its stack requirements.
785    
786    19. If the /S+ option was used in pcretest to study a pattern using JIT,
787        subsequent uses of /S (without +) incorrectly behaved like /S+.
788    
789    21. Retrieve executable code size support for the JIT compiler and fixing
790        some warnings.
791    
792    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
793        not work when the shorter character appeared right at the end of the
794        subject string.
795    
796    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
797        systems.
798    
799    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
800        output it when the /M option is used in pcretest.
801    
802    25. The CheckMan script was not being included in the distribution. Also, added
803        an explicit "perl" to run Perl scripts from the PrepareRelease script
804        because this is reportedly needed in Windows.
805    
806    26. If study data was being save in a file and studying had not found a set of
807        "starts with" bytes for the pattern, the data written to the file (though
808        never used) was taken from uninitialized memory and so caused valgrind to
809        complain.
810    
811    27. Updated RunTest.bat as provided by Sheri Pierce.
812    
813    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
814    
815    29. Computation of memory usage for the table of capturing group names was
816        giving an unnecessarily large value.
817    
818    
819    Version 8.20 21-Oct-2011
820    ------------------------
821    
822    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
823        a POSIX class. After further experiments with Perl, which convinced me that
824        Perl has bugs and confusions, a closing square bracket is no longer allowed
825        in a POSIX name. This bug also affected patterns with classes that started
826        with full stops.
827    
828    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
829        captured substring, but while checking the failing first alternative,
830        substring 1 is temporarily captured. If the output vector supplied to
831        pcre_exec() was not big enough for this capture, the yield of the function
832        was still zero ("insufficient space for captured substrings"). This cannot
833        be totally fixed without adding another stack variable, which seems a lot
834        of expense for a edge case. However, I have improved the situation in cases
835        such as /(a)(b)x|abc/ matched against "abc", where the return code
836        indicates that fewer than the maximum number of slots in the ovector have
837        been set.
838    
839    3.  Related to (2) above: when there are more back references in a pattern than
840        slots in the output vector, pcre_exec() uses temporary memory during
841        matching, and copies in the captures as far as possible afterwards. It was
842        using the entire output vector, but this conflicts with the specification
843        that only 2/3 is used for passing back captured substrings. Now it uses
844        only the first 2/3, for compatibility. This is, of course, another edge
845        case.
846    
847    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
848        main code base, and can be used by building with --enable-jit. When this is
849        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
850        runtime --no-jit option is given.
851    
852    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
853        ovector, the return from the function was zero, implying that there were
854        other matches that did not fit. The correct "exactly full" value is now
855        returned.
856    
857    6.  If a subpattern that was called recursively or as a subroutine contained
858        (*PRUNE) or any other control that caused it to give a non-standard return,
859        invalid errors such as "Error -26 (nested recursion at the same subject
860        position)" or even infinite loops could occur.
861    
862    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
863        computing the minimum length on reaching *ACCEPT, and so ended up with the
864        wrong value of 1 rather than 0. Further investigation indicates that
865        computing a minimum subject length in the presence of *ACCEPT is difficult
866        (think back references, subroutine calls), and so I have changed the code
867        so that no minimum is registered for a pattern that contains *ACCEPT.
868    
869    8.  If (*THEN) was present in the first (true) branch of a conditional group,
870        it was not handled as intended. [But see 16 below.]
871    
872    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
873        Sheri Pierce.
874    
875    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
876        the first byte in a match must be "a".
877    
878    11. Change 17 for 8.13 increased the recursion depth for patterns like
879        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
880        pattern contains any instances of (*THEN). If it does not, the old
881        optimizations are restored. It would be nice to do this on a per-group
882        basis, but at the moment that is not feasible.
883    
884    12. In some environments, the output of pcretest -C is CRLF terminated. This
885        broke RunTest's code that checks for the link size. A single white space
886        character after the value is now allowed for.
887    
888    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
889        For "fr", it uses the Windows-specific input and output files.
890    
891    14. If (*THEN) appeared in a group that was called recursively or as a
892        subroutine, it did not work as intended. [But see next item.]
893    
894    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
895        pattern fragments (but not containing any | characters). If A and B are
896        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
897        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
898        D. In other words, Perl considers parentheses that do not contain any |
899        characters to be part of a surrounding alternative, whereas PCRE was
900        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
901        differently. PCRE now behaves in the same way as Perl, except in the case
902        of subroutine/recursion calls such as (?1) which have in any case always
903        been different (but PCRE had them first :-).
904    
905    16. Related to 15 above: Perl does not treat the | in a conditional group as
906        creating alternatives. Such a group is treated in the same way as an
907        ordinary group without any | characters when processing (*THEN). PCRE has
908        been changed to match Perl's behaviour.
909    
910    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
911        RunGrepTest script failed.
912    
913    18. Change 22 for version 13 caused atomic groups to use more stack. This is
914        inevitable for groups that contain captures, but it can lead to a lot of
915        stack use in large patterns. The old behaviour has been restored for atomic
916        groups that do not contain any capturing parentheses.
917    
918    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
919        suppress the check for a minimum subject length at run time. (If it was
920        given to pcre_exec() or pcre_dfa_exec() it did work.)
921    
922    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
923        fail to work when decoding hex characters in data strings in EBCDIC
924        environments.
925    
926    21. It appears that in at least one Mac OS environment, the isxdigit() function
927        is implemented as a macro that evaluates to its argument more than once,
928        contravening the C 90 Standard (I haven't checked a later standard). There
929        was an instance in pcretest which caused it to go wrong when processing
930        \x{...} escapes in subject strings. The has been rewritten to avoid using
931        things like p++ in the argument of isxdigit().
932    
933    
934    Version 8.13 16-Aug-2011
935    ------------------------
936    
937    1.  The Unicode data tables have been updated to Unicode 6.0.0.
938    
939    2.  Two minor typos in pcre_internal.h have been fixed.
940    
941    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
942        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
943        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
944    
945    4.  There were a number of related bugs in the code for matching backrefences
946        caselessly in UTF-8 mode when codes for the characters concerned were
947        different numbers of bytes. For example, U+023A and U+2C65 are an upper
948        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
949        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
950        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
951        2-byte code at the end of the subject (it thought there wasn't enough data
952        left).
953    
954    5.  Comprehensive information about what went wrong is now returned by
955        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
956        as the output vector has at least 2 elements. The offset of the start of
957        the failing character and a reason code are placed in the vector.
958    
959    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
960        now returned is for the first byte of the failing character, instead of the
961        last byte inspected. This is an incompatible change, but I hope it is small
962        enough not to be a problem. It makes the returned offset consistent with
963        pcre_exec() and pcre_dfa_exec().
964    
965    7.  pcretest now gives a text phrase as well as the error number when
966        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
967        failure, the offset and reason code are output.
968    
969    8.  When \R was used with a maximizing quantifier it failed to skip backwards
970        over a \r\n pair if the subsequent match failed. Instead, it just skipped
971        back over a single character (\n). This seems wrong (because it treated the
972        two characters as a single entity when going forwards), conflicts with the
973        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
974        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
975        has been changed.
976    
977    9.  Some internal refactoring has changed the processing so that the handling
978        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
979        time (the PCRE_DOTALL option was changed this way some time ago: version
980        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
981        which was always a bit of a fudge. It also means that there is one less
982        argument for the match() function, which reduces its stack requirements
983        slightly. This change also fixes an incompatibility with Perl: the pattern
984        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
985    
986    10. More internal refactoring has drastically reduced the number of recursive
987        calls to match() for possessively repeated groups such as (abc)++ when
988        using pcre_exec().
989    
990    11. While implementing 10, a number of bugs in the handling of groups were
991        discovered and fixed:
992    
993        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
994        (a|)*(?1) gave a compile-time internal error.
995        ((a|)+)+  did not notice that the outer group could match an empty string.
996        (^a|^)+   was not marked as anchored.
997        (.*a|.*)+ was not marked as matching at start or after a newline.
998    
999    12. Yet more internal refactoring has removed another argument from the match()
1000        function. Special calls to this function are now indicated by setting a
1001        value in a variable in the "match data" data block.
1002    
1003    13. Be more explicit in pcre_study() instead of relying on "default" for
1004        opcodes that mean there is no starting character; this means that when new
1005        ones are added and accidentally left out of pcre_study(), testing should
1006        pick them up.
1007    
1008    14. The -s option of pcretest has been documented for ages as being an old
1009        synonym of -m (show memory usage). I have changed it to mean "force study
1010        for every regex", that is, assume /S for every regex. This is similar to -i
1011        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1012        using it. It makes it easier to run collections of tests with and without
1013        study enabled, and thereby test pcre_study() more easily. All the standard
1014        tests are now run with and without -s (but some patterns can be marked as
1015        "never study" - see 20 below).
1016    
1017    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1018        restoration of the capturing data to the outer values was not happening
1019        correctly.
1020    
1021    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1022        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1023        pattern had matched an empty string, and so incorrectly returned a no
1024        match.
1025    
1026    17. There was optimizing code for the last branch of non-capturing parentheses,
1027        and also for the obeyed branch of a conditional subexpression, which used
1028        tail recursion to cut down on stack usage. Unfortunately, now that there is
1029        the possibility of (*THEN) occurring in these branches, tail recursion is
1030        no longer possible because the return has to be checked for (*THEN). These
1031        two optimizations have therefore been removed. [But see 8.20/11 above.]
1032    
1033    18. If a pattern containing \R was studied, it was assumed that \R always
1034        matched two bytes, thus causing the minimum subject length to be
1035        incorrectly computed because \R can also match just one byte.
1036    
1037    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1038        was incorrectly computed.
1039    
1040    20. If /S is present twice on a test pattern in pcretest input, it now
1041        *disables* studying, thereby overriding the use of -s on the command line
1042        (see 14 above). This is necessary for one or two tests to keep the output
1043        identical in both cases.
1044    
1045    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1046        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1047    
1048    22. When an atomic group that contained a capturing parenthesis was
1049        successfully matched, but the branch in which it appeared failed, the
1050        capturing was not being forgotten if a higher numbered group was later
1051        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1052        group 1 to "a", when in fact it should be unset. This applied to multi-
1053        branched capturing and non-capturing groups, repeated or not, and also to
1054        positive assertions (capturing in negative assertions does not happen
1055        in PCRE) and also to nested atomic groups.
1056    
1057    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1058        subject after a captured substring, to make it easier to tell which of a
1059        number of identical substrings has been captured.
1060    
1061    24. The way atomic groups are processed by pcre_exec() has been changed so that
1062        if they are repeated, backtracking one repetition now resets captured
1063        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1064        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1065        "aaa". Previously, it would have been "a". As part of this code
1066        refactoring, the way recursive calls are handled has also been changed.
1067    
1068    25. If an assertion condition captured any substrings, they were not passed
1069        back unless some other capturing happened later. For example, if
1070        (?(?=(a))a) was matched against "a", no capturing was returned.
1071    
1072    26. When studying a pattern that contained subroutine calls or assertions,
1073        the code for finding the minimum length of a possible match was handling
1074        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1075        group 1 called group 2 while simultaneously a separate group 2 called group
1076        1). A stack overflow occurred in this case. I have fixed this by limiting
1077        the recursion depth to 10.
1078    
1079    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1080        Fortmann. This supports explicit test numbers on the command line, and has
1081        argument validation and error reporting.
1082    
1083    28. An instance of \X with an unlimited repeat could fail if at any point the
1084        first character it looked at was a mark character.
1085    
1086    29. Some minor code refactoring concerning Unicode properties and scripts
1087        should reduce the stack requirement of match() slightly.
1088    
1089    30. Added the '=' option to pcretest to check the setting of unused capturing
1090        slots at the end of the pattern, which are documented as being -1, but are
1091        not included in the return count.
1092    
1093    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1094        compiled something random. Now it gives a compile-time error (as does
1095        Perl).
1096    
1097    32. A *MARK encountered during the processing of a positive assertion is now
1098        recorded and passed back (compatible with Perl).
1099    
1100    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1101        had alternative anchored branches, the search for a second match in a line
1102        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1103        matched the line "0102" twice. The same bug affected patterns that started
1104        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1105        twice.
1106    
1107    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1108        does, and because of capturing effects, quantifying parenthesized
1109        assertions may at times be useful. Quantifiers are now allowed for
1110        parenthesized assertions.
1111    
1112    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1113    
1114    36. \g was being checked for fancy things in a character class, when it should
1115        just be a literal "g".
1116    
1117    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1118        appearance of a nested POSIX class supersedes an apparent external class.
1119        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1120        unescaped square brackets may also appear as part of class names. For
1121        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1122        more like Perl. (But see 8.20/1 above.)
1123    
1124    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1125        was because it thought it was \N{name}, which is not supported).
1126    
1127    39. Add minix to OS list not supporting the -S option in pcretest.
1128    
1129    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1130        cannot analyze patterns in sufficient detail to catch mutual recursions
1131        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1132        subgroup is called recursively as a subpattern for a second time at the
1133        same position in the subject string. In previous releases this might have
1134        been caught by the recursion limit, or it might have run out of stack.
1135    
1136    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1137        happen only once. PCRE was, however incorrectly giving a compile time error
1138        "recursive call could loop indefinitely" because it cannot analyze the
1139        pattern in sufficient detail. The compile time test no longer happens when
1140        PCRE is compiling a conditional subpattern, but actual runaway loops are
1141        now caught at runtime (see 40 above).
1142    
1143    42. It seems that Perl allows any characters other than a closing parenthesis
1144        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1145        has been changed to be the same.
1146    
1147    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1148        as not to get warnings when autogen.sh is called. Also changed
1149        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1150    
1151    44. To help people who use pcregrep to scan files containing exceedingly long
1152        lines, the following changes have been made:
1153    
1154        (a) The default value of the buffer size parameter has been increased from
1155            8K to 20K. (The actual buffer used is three times this size.)
1156    
1157        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1158            PCRE is built.
1159    
1160        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1161            to be set at run time.
1162    
1163        (d) Numerical values in pcregrep options can be followed by K or M, for
1164            example --buffer-size=50K.
1165    
1166        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1167            given and the return code is set to 2.
1168    
1169    45. Add a pointer to the latest mark to the callout data block.
1170    
1171    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1172        partial match of an empty string instead of no match. This was specific to
1173        the use of ".".
1174    
1175    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1176        complete match instead of a partial match. This bug was dependent on both
1177        the PCRE_UTF8 and PCRE_DOTALL options being set.
1178    
1179    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1180        starting byte set, because \b was not being ignored.
1181    
1182    
1183    Version 8.12 15-Jan-2011
1184    ------------------------
1185    
1186    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1187        checks for such things as part of the documentation building process.
1188    
1189    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1190        --match-limit and --recursion-limit options (added for 8.11). In
1191        particular, this made one of the standard tests fail. (The integer value
1192        went into the wrong half of a long int.)
1193    
1194    3.  If the --colour option was given to pcregrep with -v (invert match), it
1195        did strange things, either producing crazy output, or crashing. It should,
1196        of course, ignore a request for colour when reporting lines that do not
1197        match.
1198    
1199    4.  Another pcregrep bug caused similar problems if --colour was specified with
1200        -M (multiline) and the pattern match finished with a line ending.
1201    
1202    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1203        matched in multiline mode, the following line was shown as part of the
1204        match. This seems wrong, so I have changed it.
1205    
1206    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1207        the check for further matches in the same line (so they could be coloured)
1208        to overrun the end of the current line. If another match was found, it was
1209        incorrectly shown (and then shown again when found in the next line).
1210    
1211    7.  If pcregrep was compiled under Windows, there was a reference to the
1212        function pcregrep_exit() before it was defined. I am assuming this was
1213        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1214        reported by a user. I've moved the definition above the reference.
1215    
1216    
1217    Version 8.11 10-Dec-2010
1218  ------------------------  ------------------------
1219    
1220  1.  (*THEN) was not working properly if there were untried alternatives prior  1.  (*THEN) was not working properly if there were untried alternatives prior
1221      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1222      backtracked to try for "b" instead of moving to the next alternative branch      backtracked to try for "b" instead of moving to the next alternative branch
1223      at the same level (in this case, to look for "c"). The Perl documentation      at the same level (in this case, to look for "c"). The Perl documentation
1224      is clear that when (*THEN) is backtracked onto, it goes to the "next      is clear that when (*THEN) is backtracked onto, it goes to the "next
1225      alternative in the innermost enclosing group".      alternative in the innermost enclosing group".
1226    
1227  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1228      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1229      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1230      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1231      (*THEN).      (*THEN).
1232    
1233  3.  If \s appeared in a character class, it removed the VT character from  3.  If \s appeared in a character class, it removed the VT character from
1234      the class, even if it had been included by some previous item, for example      the class, even if it had been included by some previous item, for example
1235      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1236      of \s, but is part of the POSIX "space" class.)      of \s, but is part of the POSIX "space" class.)
1237    
1238  4.  A partial match never returns an empty string (because you can always  4.  A partial match never returns an empty string (because you can always
1239      match an empty string at the end of the subject); however the checking for      match an empty string at the end of the subject); however the checking for
1240      an empty string was starting at the "start of match" point. This has been      an empty string was starting at the "start of match" point. This has been
# Line 31  Version 8.11 10-Oct-2010 Line 1244  Version 8.11 10-Oct-2010
1244      (previously it gave "no match").      (previously it gave "no match").
1245    
1246  5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching  5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1247      of $, \z, \Z, \b, and \B. If the match point is at the end of the string,      of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1248      previously a full match would be given. However, setting PCRE_PARTIAL_HARD      previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1249      has an implication that the given string is incomplete (because a partial      has an implication that the given string is incomplete (because a partial
1250      match is preferred over a full match). For this reason, these items now      match is preferred over a full match). For this reason, these items now
1251      give a partial match in this situation. [Aside: previously, the one case      give a partial match in this situation. [Aside: previously, the one case
1252      /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial      /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1253      match rather than a full match, which was wrong by the old rules, but is      match rather than a full match, which was wrong by the old rules, but is
1254      now correct.]      now correct.]
1255    
1256  6.  There was a bug in the handling of #-introduced comments, recognized when  6.  There was a bug in the handling of #-introduced comments, recognized when
1257      PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.      PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1258      If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose      If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1259      UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when      UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1260      scanning for the end of the comment. (*Character* 0x85 is an "any" newline,      scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1261      but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several      but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1262      places in pcre_compile().      places in pcre_compile().
1263    
1264  7.  Related to (6) above, when pcre_compile() was skipping #-introduced  7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1265      comments when looking ahead for named forward references to subpatterns,      comments when looking ahead for named forward references to subpatterns,
1266      the only newline sequence it recognized was NL. It now handles newlines      the only newline sequence it recognized was NL. It now handles newlines
1267      according to the set newline convention.      according to the set newline convention.
1268    
1269  8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the  8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1270      former, but used strtoul(), whereas pcretest avoided strtoul() but did not      former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1271      cater for a lack of strerror(). These oversights have been fixed.      cater for a lack of strerror(). These oversights have been fixed.
1272    
1273  9.  Added --match-limit and --recursion-limit to pcregrep.  9.  Added --match-limit and --recursion-limit to pcregrep.
1274    
1275    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1276    
1277    11. When the -o option was used, pcregrep was setting a return code of 1, even
1278        when matches were found, and --line-buffered was not being honoured.
1279    
1280    12. Added an optional parentheses number to the -o and --only-matching options
1281        of pcregrep.
1282    
1283    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1284        can match an empty string. The code to do it in pcretest and pcredemo
1285        needed fixing:
1286    
1287        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1288            only one byte after an empty string match just before CRLF (this case
1289            just got forgotten; "any" and "anycrlf" were OK).
1290    
1291        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1292            mode when an empty string match preceded an ASCII character followed by
1293            a non-ASCII character. (The code for advancing by one character rather
1294            than one byte was nonsense.)
1295    
1296        (c) The pcredemo.c sample program did not have any code at all to handle
1297            the cases when CRLF is a valid newline sequence.
1298    
1299    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1300        as a starting offset was within the subject string. There is now a new
1301        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1302        negative or greater than the length of the string. In order to test this,
1303        pcretest is extended to allow the setting of negative starting offsets.
1304    
1305    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1306        starting offset points to the beginning of a UTF-8 character was
1307        unnecessarily clumsy. I tidied it up.
1308    
1309    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1310        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1311    
1312    17. Nobody had reported that the --include_dir option, which was added in
1313        release 7.7 should have been called --include-dir (hyphen, not underscore)
1314        for compatibility with GNU grep. I have changed it to --include-dir, but
1315        left --include_dir as an undocumented synonym, and the same for
1316        --exclude-dir, though that is not available in GNU grep, at least as of
1317        release 2.5.4.
1318    
1319    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1320        characters from a string of bytes) have been redefined so as not to use
1321        loops, in order to improve performance in some environments. At the same
1322        time, I abstracted some of the common code into auxiliary macros to save
1323        repetition (this should not affect the compiled code).
1324    
1325    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1326        compile-time error is now given if \c is not followed by an ASCII
1327        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1328        different, and any byte value is allowed.)
1329    
1330    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1331        START_OPTIMIZE option, which is now allowed at compile time - but just
1332        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1333        to pcregrep and other applications that have no direct access to PCRE
1334        options. The new /Y option in pcretest sets this option when calling
1335        pcre_compile().
1336    
1337    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1338        back references. Groups containing recursive back references were forced to
1339        be atomic by that change, but in the case of named groups, the amount of
1340        memory required was incorrectly computed, leading to "Failed: internal
1341        error: code overflow". This has been fixed.
1342    
1343    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1344        pcretest.c, to avoid build problems in some Borland environments.
1345    
1346    
1347  Version 8.10 25-Jun-2010  Version 8.10 25-Jun-2010
# Line 546  Version 7.9 11-Apr-09 Line 1830  Version 7.9 11-Apr-09
1830  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
1831      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
1832      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1833      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1834        8.33.]
1835    
1836  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1837      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 789  Version 7.7 07-May-08 Line 2074  Version 7.7 07-May-08
2074      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2075      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2076      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2077      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2078      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2079      was subsequently set up correctly.)      was subsequently set up correctly.)
2080    

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