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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.35-RC1 xx-xxxx-201x
5    -----------------------------
6    
7    1.  A new flag is set, when property checks are present in an XCLASS.
8        When this flag is not set, PCRE can perform certain optimizations
9        such as studying these XCLASS-es.
10    
11    2.  The auto-possessification of character sets were improved: a normal
12        and an extended character set can be compared now. Furthermore
13        the JIT compiler optimizes more character set checks.
14    
15    3.  Got rid of some compiler warnings for potentially uninitialized variables
16        that show up only when compiled with -O2.
17    
18    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
19        of a match later then the end of the match. The pcretest program was not
20        handling the case sensibly - it was outputting from the start to the next
21        binary zero. It now reports this situation in a message, and outputs the
22        text from the end to the start.
23    
24    5.  Fast forward search is improved in JIT. Instead of the first three
25        characters, any three characters with fixed position can be searched.
26        Search order: first, last, middle.
27    
28    6.  Improve character range checks in JIT. Characters are read by an inprecise
29        function now, which returns with an unknown value if the character code is
30        above a certain treshold (e.g: 256). The only limitation is that the value
31        must be bigger than the treshold as well. This function is useful, when
32        the characters above the treshold are handled in the same way.
33    
34    7.  The macros whose names start with RAWUCHAR are placeholders for a future
35        mode in which only the bottom 21 bits of 32-bit data items are used. To
36        make this more memorable for those maintaining the code, the names have
37        been changed to start with UCHAR21, and an extensive comment has been added
38        to their definition.
39    
40    
41    Version 8.34 15-December-2013
42    -----------------------------
43    
44    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
45        executable memory. Patch inspired by Carsten Klein.
46    
47    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
48        this macro is never tested and has no effect, because the work to support
49        coverage involves only compiling and linking options and special targets in
50        the Makefile. The comment in config.h implied that defining the macro would
51        enable coverage support, which is totally false. There was also support for
52        setting this macro in the CMake files (my fault, I just copied it from
53        configure). SUPPORT_GCOV has now been removed.
54    
55    3.  Make a small performance improvement in strlen16() and strlen32() in
56        pcretest.
57    
58    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
59        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
60        these cases). There was also one in pcretest.c.
61    
62    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
63    
64    6.  In UTF mode, the code for checking whether a group could match an empty
65        string (which is used for indefinitely repeated groups to allow for
66        breaking an infinite loop) was broken when the group contained a repeated
67        negated single-character class with a character that occupied more than one
68        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
69        UTF-8 mode). The effect was undefined: the group might or might not be
70        deemed as matching an empty string, or the program might have crashed.
71    
72    7.  The code for checking whether a group could match an empty string was not
73        recognizing that \h, \H, \v, \V, and \R must match a character.
74    
75    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
76        an empty string. If it can, pcretest shows this in its information output.
77    
78    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
79        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
80        matched by pcre_exec() without using JIT:
81    
82        (a) If the rest of the pattern did not match after a maximal run of
83            grapheme clusters, the code for backing up to try with fewer of them
84            did not always back up over a full grapheme when characters that do not
85            have the modifier quality were involved, e.g. Hangul syllables.
86    
87        (b) If the match point in a subject started with modifier character, and
88            there was no match, the code could incorrectly back up beyond the match
89            point, and potentially beyond the first character in the subject,
90            leading to a segfault or an incorrect match result.
91    
92    10. A conditional group with an assertion condition could lead to PCRE
93        recording an incorrect first data item for a match if no other first data
94        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
95        first data item, and therefore matched "ca" after "c" instead of at the
96        start.
97    
98    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
99        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
100    
101    12. The source of pcregrep now includes z/OS-specific code so that it can be
102        compiled for z/OS as part of the special z/OS distribution.
103    
104    13. Added the -T and -TM options to pcretest.
105    
106    14. The code in pcre_compile.c for creating the table of named capturing groups
107        has been refactored. Instead of creating the table dynamically during the
108        actual compiling pass, the information is remembered during the pre-compile
109        pass (on the stack unless there are more than 20 named groups, in which
110        case malloc() is used) and the whole table is created before the actual
111        compile happens. This has simplified the code (it is now nearly 150 lines
112        shorter) and prepared the way for better handling of references to groups
113        with duplicate names.
114    
115    15. A back reference to a named subpattern when there is more than one of the
116        same name now checks them in the order in which they appear in the pattern.
117        The first one that is set is used for the reference. Previously only the
118        first one was inspected. This change makes PCRE more compatible with Perl.
119    
120    16. Unicode character properties were updated from Unicode 6.3.0.
121    
122    17. The compile-time code for auto-possessification has been refactored, based
123        on a patch by Zoltan Herczeg. It now happens after instead of during
124        compilation. The code is cleaner, and more cases are handled. The option
125        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
126        options in pcretest are provided to set it. It can also be set by
127        (*NO_AUTO_POSSESS) at the start of a pattern.
128    
129    18. The character VT has been added to the default ("C" locale) set of
130        characters that match \s and are generally treated as white space,
131        following this same change in Perl 5.18. There is now no difference between
132        "Perl space" and "POSIX space". Whether VT is treated as white space in
133        other locales depends on the locale.
134    
135    19. The code for checking named groups as conditions, either for being set or
136        for being recursed, has been refactored (this is related to 14 and 15
137        above). Processing unduplicated named groups should now be as fast at
138        numerical groups, and processing duplicated groups should be faster than
139        before.
140    
141    20. Two patches to the CMake build system, by Alexander Barkov:
142    
143          (1) Replace the "source" command by "." in CMakeLists.txt because
144              "source" is a bash-ism.
145    
146          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
147              without these the CMake build does not work on Solaris.
148    
149    21. Perl has changed its handling of \8 and \9. If there is no previously
150        encountered capturing group of those numbers, they are treated as the
151        literal characters 8 and 9 instead of a binary zero followed by the
152        literals. PCRE now does the same.
153    
154    22. Following Perl, added \o{} to specify codepoints in octal, making it
155        possible to specify values greater than 0777 and also making them
156        unambiguous.
157    
158    23. Perl now gives an error for missing closing braces after \x{... instead of
159        treating the string as literal. PCRE now does the same.
160    
161    24. RunTest used to grumble if an inappropriate test was selected explicitly,
162        but just skip it when running all tests. This make it awkward to run ranges
163        of tests when one of them was inappropriate. Now it just skips any
164        inappropriate tests, as it always did when running all tests.
165    
166    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
167        character types such as \d or \w, too many callouts were inserted, and the
168        data that they returned was rubbish.
169    
170    26. In UCP mode, \s was not matching two of the characters that Perl matches,
171        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
172        were matched by \h. The code has now been refactored so that the lists of
173        the horizontal and vertical whitespace characters used for \h and \v (which
174        are defined only in one place) are now also used for \s.
175    
176    27. Add JIT support for the 64 bit TileGX architecture.
177        Patch by Jiong Wang (Tilera Corporation).
178    
179    28. Possessive quantifiers for classes (both explicit and automatically
180        generated) now use special opcodes instead of wrapping in ONCE brackets.
181    
182    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
183        (because it's meaningless), this was not happening when PCRE_CASELESS was
184        set. Not wrong, but inefficient.
185    
186    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
187        properties for \w, \d, etc) is present in a test regex. Otherwise if the
188        test contains no characters greater than 255, Perl doesn't realise it
189        should be using Unicode semantics.
190    
191    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
192        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
193        does in Unicode mode.
194    
195    32. Added the "forbid" facility to pcretest so that putting tests into the
196        wrong test files can sometimes be quickly detected.
197    
198    33. There is now a limit (default 250) on the depth of nesting of parentheses.
199        This limit is imposed to control the amount of system stack used at compile
200        time. It can be changed at build time by --with-parens-nest-limit=xxx or
201        the equivalent in CMake.
202    
203    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
204        errors. Perl warns for these when in warning mode, but PCRE has no facility
205        for giving warnings.
206    
207    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
208        However, this was not working for (?!) because it is optimized to (*FAIL),
209        for which PCRE does not allow quantifiers. The optimization is now disabled
210        when a quantifier follows (?!). I can't see any use for this, but it makes
211        things uniform.
212    
213    36. Perl no longer allows group names to start with digits, so I have made this
214        change also in PCRE. It simplifies the code a bit.
215    
216    37. In extended mode, Perl ignores spaces before a + that indicates a
217        possessive quantifier. PCRE allowed a space before the quantifier, but not
218        before the possessive +. It now does.
219    
220    38. The use of \K (reset reported match start) within a repeated possessive
221        group such as (a\Kb)*+ was not working.
222    
223    40. Document that the same character tables must be used at compile time and
224        run time, and that the facility to pass tables to pcre_exec() and
225        pcre_dfa_exec() is for use only with saved/restored patterns.
226    
227    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
228        features for Builds with MSVC:
229    
230        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
231           builds). The .rc files can be used to set FileDescription and many other
232           attributes.
233    
234        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
235           This allows higher-level build scripts which want .pdb files to avoid
236           hard-coding the exact files needed."
237    
238    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
239        mean "start of word" and "end of word", respectively, as a transition aid.
240    
241    43. A minimizing repeat of a class containing codepoints greater than 255 in
242        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
243        compiled to use the heap for recursion.
244    
245    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
246        is configured.
247    
248    
249    Version 8.33 28-May-2013
250    ------------------------
251    
252    1.  Added 'U' to some constants that are compared to unsigned integers, to
253        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
254        variables that are added to signed variables, to ensure the result is
255        signed and can be negated.
256    
257    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
258        CMake config files.
259    
260    3.  Revise the creation of config.h.generic so that all boolean macros are
261        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
262        overriding via -D on the command line possible.
263    
264    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
265        to unsigned int is reported to make a quite noticeable speed difference in
266        a specific Windows environment. Testing on Linux did also appear to show
267        some benefit (and it is clearly not harmful). Also fixed the definition of
268        Xop which should be unsigned.
269    
270    5.  Related to (4), changing the definition of the intermediate variable cc
271        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
272        improvements.
273    
274    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
275        unnecessary spaces.
276    
277    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
278        and later.
279    
280    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
281    
282    9.  Optimizing fast_forward_start_bits in JIT.
283    
284    10. Adding support for callouts in JIT, and fixing some issues revealed
285        during this work. Namely:
286    
287        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
288    
289        (b) Minimum length was not checked before the matching is started.
290    
291    11. The value of capture_last that is passed to callouts was incorrect in some
292        cases when there was a capture on one path that was subsequently abandoned
293        after a backtrack. Also, the capture_last value is now reset after a
294        recursion, since all captures are also reset in this case.
295    
296    12. The interpreter no longer returns the "too many substrings" error in the
297        case when an overflowing capture is in a branch that is subsequently
298        abandoned after a backtrack.
299    
300    13. In the pathological case when an offset vector of size 2 is used, pcretest
301        now prints out the matched string after a yield of 0 or 1.
302    
303    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
304        Only supported by the JIT compiler at the moment.
305    
306    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
307    
308    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
309        offset of the starting point of the matching process, provided the offsets
310        vector is large enough.
311    
312    17. The \A escape now records a lookbehind value of 1, though its execution
313        does not actually inspect the previous character. This is to ensure that,
314        in partial multi-segment matching, at least one character from the old
315        segment is retained when a new segment is processed. Otherwise, if there
316        are no lookbehinds in the pattern, \A might match incorrectly at the start
317        of a new segment.
318    
319    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
320    
321    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
322        gives some modest performance improvement in 8-bit mode.
323    
324    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
325        be expressed in certain programming languages using Universal Character
326        Names.
327    
328    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
329        which points out that "non characters" are not "characters that may not
330        appear in Unicode strings" but rather "characters that are reserved for
331        internal use and have only local meaning".
332    
333    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
334        there was a conditional group that depended on an assertion, if the
335        assertion was false, the callout that immediately followed the alternation
336        in the condition was skipped when pcre_exec() was used for matching.
337    
338    23. Allow an explicit callout to be inserted before an assertion that is the
339        condition for a conditional group, for compatibility with automatic
340        callouts, which always insert a callout at this point.
341    
342    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
343        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
344    
345    25. (*PRUNE) is now supported by the JIT compiler.
346    
347    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
348    
349    27. Fix the case where there are two or more SKIPs with arguments that may be
350        ignored.
351    
352    28. (*SKIP) is now supported by the JIT compiler.
353    
354    29. (*THEN) is now supported by the JIT compiler.
355    
356    30. Update RunTest with additional test selector options.
357    
358    31. The way PCRE handles backtracking verbs has been changed in two ways.
359    
360        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
361        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
362        backtracking. In some cases this makes it more Perl-compatible, but Perl's
363        rather obscure rules do not always do the same thing.
364    
365        (2) Previously, backtracking verbs were confined within assertions. This is
366        no longer the case for positive assertions, except for (*ACCEPT). Again,
367        this sometimes improves Perl compatibility, and sometimes does not.
368    
369    32. A number of tests that were in test 2 because Perl did things differently
370        have been moved to test 1, because either Perl or PCRE has changed, and
371        these tests are now compatible.
372    
373    32. Backtracking control verbs are now handled in the same way in JIT and
374        interpreter.
375    
376    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
377        contained a forward subroutine reference caused a compile error.
378    
379    34. Auto-detect and optimize limited repetitions in JIT.
380    
381    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
382        blocking (*UTF) etc.
383    
384    36. In the interpreter, maximizing pattern repetitions for characters and
385        character types now use tail recursion, which reduces stack usage.
386    
387    37. The value of the max lookbehind was not correctly preserved if a compiled
388        and saved regex was reloaded on a host of different endianness.
389    
390    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
391        of the compiled pattern block, expand the flags field from 16 to 32 bits
392        because it was almost full.
393    
394    39. Try madvise first before posix_madvise.
395    
396    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
397        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
398        original change locked out all matches of empty strings. This has been
399        changed so that one match of an empty string per line is recognized.
400        Subsequent searches on the same line (for colouring or for --only-matching,
401        for example) do not recognize empty strings.
402    
403    41. Applied a user patch to fix a number of spelling mistakes in comments.
404    
405    42. Data lines longer than 65536 caused pcretest to crash.
406    
407    43. Clarified the data type for length and startoffset arguments for pcre_exec
408        and pcre_dfa_exec in the function-specific man pages, where they were
409        explicitly stated to be in bytes, never having been updated. I also added
410        some clarification to the pcreapi man page.
411    
412    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
413        a segmentation fault.
414    
415    
416    Version 8.32 30-November-2012
417    -----------------------------
418    
419    1.  Improved JIT compiler optimizations for first character search and single
420        character iterators.
421    
422    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
423        Patch by Daniel Richard G.
424    
425    3.  Single character iterator optimizations in the JIT compiler.
426    
427    4.  Improved JIT compiler optimizations for character ranges.
428    
429    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
430        Reported by Giuseppe D'Angelo.
431    
432    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
433        of a line, was being set incorrectly in cases where .* appeared inside
434        atomic brackets at the start of a pattern, or where there was a subsequent
435        *PRUNE or *SKIP.
436    
437    7.  Improved instruction cache flush for POWER/PowerPC.
438        Patch by Daniel Richard G.
439    
440    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
441        grep:
442    
443        (a) There is now no limit to the number of patterns to be matched.
444    
445        (b) An error is given if a pattern is too long.
446    
447        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
448            are now supported.
449    
450        (d) --exclude-from and --include-from (multiple use) have been added.
451    
452        (e) Exclusions and inclusions now apply to all files and directories, not
453            just to those obtained from scanning a directory recursively.
454    
455        (f) Multiple uses of -f and --file-list are now supported.
456    
457        (g) In a Windows environment, the default for -d has been changed from
458            "read" (the GNU grep default) to "skip", because otherwise the presence
459            of a directory in the file list provokes an error.
460    
461        (h) The documentation has been revised and clarified in places.
462    
463    9.  Improve the matching speed of capturing brackets.
464    
465    10. Changed the meaning of \X so that it now matches a Unicode extended
466        grapheme cluster.
467    
468    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
469        out POSIX threads when JIT support is configured.
470    
471    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
472    
473    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
474        structure could go wrong in environments where size_t is not the same size
475        as int.
476    
477    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
478        set.
479    
480    15. The EBCDIC support had decayed; later updates to the code had included
481        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
482        general tidy up of EBCDIC-related issues, and the documentation was also
483        not quite right. There is now a test that can be run on ASCII systems to
484        check some of the EBCDIC-related things (but is it not a full test).
485    
486    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
487        in a small tidy to the code.
488    
489    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
490    
491    18. If the --only-matching (-o) option in pcregrep is specified multiple
492        times, each one causes appropriate output. For example, -o1 -o2 outputs the
493        substrings matched by the 1st and 2nd capturing parentheses. A separating
494        string can be specified by --om-separator (default empty).
495    
496    19. Improving the first n character searches.
497    
498    20. Turn case lists for horizontal and vertical white space into macros so that
499        they are defined only once.
500    
501    21. This set of changes together give more compatible Unicode case-folding
502        behaviour for characters that have more than one other case when UCP
503        support is available.
504    
505        (a) The Unicode property table now has offsets into a new table of sets of
506            three or more characters that are case-equivalent. The MultiStage2.py
507            script that generates these tables (the pcre_ucd.c file) now scans
508            CaseFolding.txt instead of UnicodeData.txt for character case
509            information.
510    
511        (b) The code for adding characters or ranges of characters to a character
512            class has been abstracted into a generalized function that also handles
513            case-independence. In UTF-mode with UCP support, this uses the new data
514            to handle characters with more than one other case.
515    
516        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
517            whose other case is greater than 256 are now correctly matched
518            caselessly. Previously, the high codepoint matched the low one, but not
519            vice versa.
520    
521        (d) The processing of \h, \H, \v, and \ in character classes now makes use
522            of the new class addition function, using character lists defined as
523            macros alongside the case definitions of 20 above.
524    
525        (e) Caseless back references now work with characters that have more than
526            one other case.
527    
528        (f) General caseless matching of characters with more than one other case
529            is supported.
530    
531    22. Unicode character properties were updated from Unicode 6.2.0
532    
533    23. Improved CMake support under Windows. Patch by Daniel Richard G.
534    
535    24. Add support for 32-bit character strings, and UTF-32
536    
537    25. Major JIT compiler update (code refactoring and bugfixing).
538        Experimental Sparc 32 support is added.
539    
540    26. Applied a modified version of Daniel Richard G's patch to create
541        pcre.h.generic and config.h.generic by "make" instead of in the
542        PrepareRelease script.
543    
544    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
545        pcre_compile.c when checking for a zero character.
546    
547    28. Introducing a native interface for JIT. Through this interface, the compiled
548        machine code can be directly executed. The purpose of this interface is to
549        provide fast pattern matching, so several sanity checks are not performed.
550        However, feature tests are still performed. The new interface provides
551        1.4x speedup compared to the old one.
552    
553    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
554        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
555        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
556    
557    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
558        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
559        the "old" RFC 2279). Instead, it ended up passing a negative length to
560        pcre_exec().
561    
562    31. Add support for GCC's visibility feature to hide internal functions.
563    
564    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
565        "unknown -C option" after outputting 0 or 1.
566    
567    33. There is now support for generating a code coverage report for the test
568        suite in environments where gcc is the compiler and lcov is installed. This
569        is mainly for the benefit of the developers.
570    
571    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
572        unaddressable using valgrind annotations, allowing valgrind to detect
573        invalid memory accesses. This is mainly for the benefit of the developers.
574    
575    25. (*UTF) can now be used to start a pattern in any of the three libraries.
576    
577    26. Give configure error if --enable-cpp but no C++ compiler found.
578    
579    
580    Version 8.31 06-July-2012
581    -------------------------
582    
583    1.  Fixing a wrong JIT test case and some compiler warnings.
584    
585    2.  Removed a bashism from the RunTest script.
586    
587    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
588        to unsigned type, result still unsigned" that was given by an MS compiler
589        on encountering the code "-sizeof(xxx)".
590    
591    4.  Partial matching support is added to the JIT compiler.
592    
593    5.  Fixed several bugs concerned with partial matching of items that consist
594        of more than one character:
595    
596        (a) /^(..)\1/ did not partially match "aba" because checking references was
597            done on an "all or nothing" basis. This also applied to repeated
598            references.
599    
600        (b) \R did not give a hard partial match if \r was found at the end of the
601            subject.
602    
603        (c) \X did not give a hard partial match after matching one or more
604            characters at the end of the subject.
605    
606        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
607            a partial match for the string "\r".
608    
609        (e) When newline was set to CRLF, the metacharacter "." did not recognize
610            a partial match for a CR character at the end of the subject string.
611    
612    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
613        running pcretest, the text "(JIT)" added to the output whenever JIT is
614        actually used to run the match.
615    
616    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
617        or /S+[+] with a digit between 1 and 7.
618    
619    8.  OP_NOT now supports any UTF character not just single-byte ones.
620    
621    9.  (*MARK) control verb is now supported by the JIT compiler.
622    
623    10. The command "./RunTest list" lists the available tests without actually
624        running any of them. (Because I keep forgetting what they all are.)
625    
626    11. Add PCRE_INFO_MAXLOOKBEHIND.
627    
628    12. Applied a (slightly modified) user-supplied patch that improves performance
629        when the heap is used for recursion (compiled with --disable-stack-for-
630        recursion). Instead of malloc and free for each heap frame each time a
631        logical recursion happens, frames are retained on a chain and re-used where
632        possible. This sometimes gives as much as 30% improvement.
633    
634    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
635        call.
636    
637    14. As documented, (*COMMIT) is now confined to within a positive assertion.
638    
639    15. It is now possible to link pcretest with libedit as an alternative to
640        libreadline.
641    
642    16. (*COMMIT) control verb is now supported by the JIT compiler.
643    
644    17. The Unicode data tables have been updated to Unicode 6.1.0.
645    
646    18. Added --file-list option to pcregrep.
647    
648    19. Added binary file support to pcregrep, including the -a, --binary-files,
649        -I, and --text options.
650    
651    20. The madvise function is renamed for posix_madvise for QNX compatibility
652        reasons. Fixed by Giuseppe D'Angelo.
653    
654    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
655    
656    22. Changed the option for creating symbolic links for 16-bit man pages from
657        -s to -sf so that re-installing does not cause issues.
658    
659    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
660    
661    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
662        matches in certain environments (the workspace was not being correctly
663        retained). Also added to pcre_dfa_exec() a simple plausibility check on
664        some of the workspace data at the beginning of a restart.
665    
666    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
667        was not doing so when it should - probably a typo introduced by SVN 528
668        (change 8.10/14).
669    
670    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
671        \w+ when the character tables indicated that \x{c4} was a word character.
672        There were several related cases, all because the tests for doing a table
673        lookup were testing for characters less than 127 instead of 255.
674    
675    27. If a pattern contains capturing parentheses that are not used in a match,
676        their slots in the ovector are set to -1. For those that are higher than
677        any matched groups, this happens at the end of processing. In the case when
678        there were back references that the ovector was too small to contain
679        (causing temporary malloc'd memory to be used during matching), and the
680        highest capturing number was not used, memory off the end of the ovector
681        was incorrectly being set to -1. (It was using the size of the temporary
682        memory instead of the true size.)
683    
684    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
685        ovector size, it uses memory at the end of the block that it has got.
686    
687    29. Check for an overlong MARK name and give an error at compile time. The
688        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
689    
690    30. JIT compiler update.
691    
692    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
693        Rill for the patch.
694    
695    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
696    
697    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
698    
699    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
700        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
701        was enabled.
702    
703    35. Improve JIT code generation for greedy plus quantifier.
704    
705    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
706        1 to "aa" instead of to an empty string. The bug affected repeated groups
707        that could potentially match an empty string.
708    
709    37. Optimizing single character iterators in JIT.
710    
711    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
712        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
713        codepoints that are too big for the mode are faulted, and in a UTF mode,
714        disallowed codepoints are also faulted.
715    
716    39. If PCRE was compiled with UTF support, in three places in the DFA
717        matcher there was code that should only have been obeyed in UTF mode, but
718        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
719        processing when bytes with values greater than 127 were present. In 16-bit
720        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
721        both cases the values are those that cannot be the first data item in a UTF
722        character. The three items that might have provoked this were recursions,
723        possessively repeated groups, and atomic groups.
724    
725    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
726        and pcregrep, because some OS require shared objects to be explicitly
727        passed to ld, causing the link step to fail if they are not.
728    
729    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
730        mode, patterns that started with \h* or \R* might be incorrectly matched.
731    
732    
733    Version 8.30 04-February-2012
734    -----------------------------
735    
736    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
737        name is defined in ctype.h.
738    
739    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
740        only in quite long subpatterns.
741    
742    3.  Removed the function pcre_info(), which has been obsolete and deprecated
743        since it was replaced by pcre_fullinfo() in February 2000.
744    
745    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
746        match a (*MARK), and the match failed at the start of the subject, a
747        reference to memory before the start of the subject could occur. This bug
748        was introduced by fix 17 of release 8.21.
749    
750    5.  A reference to an unset group with zero minimum repetition was giving
751        totally wrong answers (in non-JavaScript-compatibility mode). For example,
752        /(another)?(\1?)test/ matched against "hello world test". This bug was
753        introduced in release 8.13.
754    
755    6.  Add support for 16-bit character strings (a large amount of work involving
756        many changes and refactorings).
757    
758    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
759        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
760        from a file.
761    
762    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
763        rounding is not applied in this particular case).
764    
765    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
766        if they appear, or are escaped, in patterns.
767    
768    10. Get rid of a number of -Wunused-but-set-variable warnings.
769    
770    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
771        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
772        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
773        also returns the mark "x". This bug applied to capturing parentheses,
774        non-capturing parentheses, and atomic parentheses. It also applied to some
775        assertions.
776    
777    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
778        information out of configure.ac instead of relying on pcre.h.generic, which
779        is not stored in the repository.
780    
781    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
782        -lreadline.
783    
784    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
785    
786    15. Applied Graycode's patch to put the top-level frame on the stack rather
787        than the heap when not using the stack for recursion. This gives a
788        performance improvement in many cases when recursion is not deep.
789    
790    16. Experimental code added to "pcretest -C" to output the stack frame size.
791    
792    
793    Version 8.21 12-Dec-2011
794    ------------------------
795    
796    1.  Updating the JIT compiler.
797    
798    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
799        are added as well.
800    
801    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
802        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
803        calling _pcre_jit_exec. Some extra comments are added.
804    
805    4.  (*MARK) settings inside atomic groups that do not contain any capturing
806        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
807        was introduced by change 18 for 8.20.
808    
809    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
810        ECMA-262 standard.
811    
812    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
813        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
814        This bug was probably introduced by change 9 of 8.13.
815    
816    7.  While fixing 6 above, I noticed that a number of other items were being
817        incorrectly rejected as "not fixed length". This arose partly because newer
818        opcodes had not been added to the fixed-length checking code. I have (a)
819        corrected the bug and added tests for these items, and (b) arranged for an
820        error to occur if an unknown opcode is encountered while checking for fixed
821        length instead of just assuming "not fixed length". The items that were
822        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
823        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
824        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
825    
826    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
827        being incorrectly compiled and would have given unpredicatble results.
828    
829    9.  A possessively repeated subpattern with minimum repeat count greater than
830        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
831        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
832        the first (A) could occur when it should not.
833    
834    10. Add a cast and remove a redundant test from the code.
835    
836    11. JIT should use pcre_malloc/pcre_free for allocation.
837    
838    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
839        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
840        is anything other than /usr, -L is still shown).
841    
842    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
843    
844    14. Perl does not support \N without a following name in a [] class; PCRE now
845        also gives an error.
846    
847    15. If a forward reference was repeated with an upper limit of around 2000,
848        it caused the error "internal error: overran compiling workspace". The
849        maximum number of forward references (including repeats) was limited by the
850        internal workspace, and dependent on the LINK_SIZE. The code has been
851        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
852        the default depends on LINK_SIZE. There is a new upper limit (for safety)
853        of around 200,000 forward references. While doing this, I also speeded up
854        the filling in of repeated forward references.
855    
856    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
857        incorrectly expecting the subject to contain another "a" after the start.
858    
859    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
860        in the match, the SKIP should be ignored. This was not happening; instead
861        the SKIP was being treated as NOMATCH. For patterns such as
862        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
863        tested.
864    
865    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
866        now much more compatible with Perl, in particular in cases where the result
867        is a non-match for a non-anchored pattern. For example, if
868        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
869        "m", where previously it did not return a name. A side effect of this
870        change is that for partial matches, the last encountered mark name is
871        returned, as for non matches. A number of tests that were previously not
872        Perl-compatible have been moved into the Perl-compatible test files. The
873        refactoring has had the pleasing side effect of removing one argument from
874        the match() function, thus reducing its stack requirements.
875    
876    19. If the /S+ option was used in pcretest to study a pattern using JIT,
877        subsequent uses of /S (without +) incorrectly behaved like /S+.
878    
879    21. Retrieve executable code size support for the JIT compiler and fixing
880        some warnings.
881    
882    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
883        not work when the shorter character appeared right at the end of the
884        subject string.
885    
886    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
887        systems.
888    
889    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
890        output it when the /M option is used in pcretest.
891    
892    25. The CheckMan script was not being included in the distribution. Also, added
893        an explicit "perl" to run Perl scripts from the PrepareRelease script
894        because this is reportedly needed in Windows.
895    
896    26. If study data was being save in a file and studying had not found a set of
897        "starts with" bytes for the pattern, the data written to the file (though
898        never used) was taken from uninitialized memory and so caused valgrind to
899        complain.
900    
901    27. Updated RunTest.bat as provided by Sheri Pierce.
902    
903    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
904    
905    29. Computation of memory usage for the table of capturing group names was
906        giving an unnecessarily large value.
907    
908    
909    Version 8.20 21-Oct-2011
910    ------------------------
911    
912    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
913        a POSIX class. After further experiments with Perl, which convinced me that
914        Perl has bugs and confusions, a closing square bracket is no longer allowed
915        in a POSIX name. This bug also affected patterns with classes that started
916        with full stops.
917    
918    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
919        captured substring, but while checking the failing first alternative,
920        substring 1 is temporarily captured. If the output vector supplied to
921        pcre_exec() was not big enough for this capture, the yield of the function
922        was still zero ("insufficient space for captured substrings"). This cannot
923        be totally fixed without adding another stack variable, which seems a lot
924        of expense for a edge case. However, I have improved the situation in cases
925        such as /(a)(b)x|abc/ matched against "abc", where the return code
926        indicates that fewer than the maximum number of slots in the ovector have
927        been set.
928    
929    3.  Related to (2) above: when there are more back references in a pattern than
930        slots in the output vector, pcre_exec() uses temporary memory during
931        matching, and copies in the captures as far as possible afterwards. It was
932        using the entire output vector, but this conflicts with the specification
933        that only 2/3 is used for passing back captured substrings. Now it uses
934        only the first 2/3, for compatibility. This is, of course, another edge
935        case.
936    
937    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
938        main code base, and can be used by building with --enable-jit. When this is
939        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
940        runtime --no-jit option is given.
941    
942    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
943        ovector, the return from the function was zero, implying that there were
944        other matches that did not fit. The correct "exactly full" value is now
945        returned.
946    
947    6.  If a subpattern that was called recursively or as a subroutine contained
948        (*PRUNE) or any other control that caused it to give a non-standard return,
949        invalid errors such as "Error -26 (nested recursion at the same subject
950        position)" or even infinite loops could occur.
951    
952    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
953        computing the minimum length on reaching *ACCEPT, and so ended up with the
954        wrong value of 1 rather than 0. Further investigation indicates that
955        computing a minimum subject length in the presence of *ACCEPT is difficult
956        (think back references, subroutine calls), and so I have changed the code
957        so that no minimum is registered for a pattern that contains *ACCEPT.
958    
959    8.  If (*THEN) was present in the first (true) branch of a conditional group,
960        it was not handled as intended. [But see 16 below.]
961    
962    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
963        Sheri Pierce.
964    
965    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
966        the first byte in a match must be "a".
967    
968    11. Change 17 for 8.13 increased the recursion depth for patterns like
969        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
970        pattern contains any instances of (*THEN). If it does not, the old
971        optimizations are restored. It would be nice to do this on a per-group
972        basis, but at the moment that is not feasible.
973    
974    12. In some environments, the output of pcretest -C is CRLF terminated. This
975        broke RunTest's code that checks for the link size. A single white space
976        character after the value is now allowed for.
977    
978    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
979        For "fr", it uses the Windows-specific input and output files.
980    
981    14. If (*THEN) appeared in a group that was called recursively or as a
982        subroutine, it did not work as intended. [But see next item.]
983    
984    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
985        pattern fragments (but not containing any | characters). If A and B are
986        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
987        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
988        D. In other words, Perl considers parentheses that do not contain any |
989        characters to be part of a surrounding alternative, whereas PCRE was
990        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
991        differently. PCRE now behaves in the same way as Perl, except in the case
992        of subroutine/recursion calls such as (?1) which have in any case always
993        been different (but PCRE had them first :-).
994    
995    16. Related to 15 above: Perl does not treat the | in a conditional group as
996        creating alternatives. Such a group is treated in the same way as an
997        ordinary group without any | characters when processing (*THEN). PCRE has
998        been changed to match Perl's behaviour.
999    
1000    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1001        RunGrepTest script failed.
1002    
1003    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1004        inevitable for groups that contain captures, but it can lead to a lot of
1005        stack use in large patterns. The old behaviour has been restored for atomic
1006        groups that do not contain any capturing parentheses.
1007    
1008    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1009        suppress the check for a minimum subject length at run time. (If it was
1010        given to pcre_exec() or pcre_dfa_exec() it did work.)
1011    
1012    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1013        fail to work when decoding hex characters in data strings in EBCDIC
1014        environments.
1015    
1016    21. It appears that in at least one Mac OS environment, the isxdigit() function
1017        is implemented as a macro that evaluates to its argument more than once,
1018        contravening the C 90 Standard (I haven't checked a later standard). There
1019        was an instance in pcretest which caused it to go wrong when processing
1020        \x{...} escapes in subject strings. The has been rewritten to avoid using
1021        things like p++ in the argument of isxdigit().
1022    
1023    
1024    Version 8.13 16-Aug-2011
1025    ------------------------
1026    
1027    1.  The Unicode data tables have been updated to Unicode 6.0.0.
1028    
1029    2.  Two minor typos in pcre_internal.h have been fixed.
1030    
1031    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
1032        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
1033        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
1034    
1035    4.  There were a number of related bugs in the code for matching backrefences
1036        caselessly in UTF-8 mode when codes for the characters concerned were
1037        different numbers of bytes. For example, U+023A and U+2C65 are an upper
1038        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
1039        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
1040        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1041        2-byte code at the end of the subject (it thought there wasn't enough data
1042        left).
1043    
1044    5.  Comprehensive information about what went wrong is now returned by
1045        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1046        as the output vector has at least 2 elements. The offset of the start of
1047        the failing character and a reason code are placed in the vector.
1048    
1049    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1050        now returned is for the first byte of the failing character, instead of the
1051        last byte inspected. This is an incompatible change, but I hope it is small
1052        enough not to be a problem. It makes the returned offset consistent with
1053        pcre_exec() and pcre_dfa_exec().
1054    
1055    7.  pcretest now gives a text phrase as well as the error number when
1056        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1057        failure, the offset and reason code are output.
1058    
1059    8.  When \R was used with a maximizing quantifier it failed to skip backwards
1060        over a \r\n pair if the subsequent match failed. Instead, it just skipped
1061        back over a single character (\n). This seems wrong (because it treated the
1062        two characters as a single entity when going forwards), conflicts with the
1063        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1064        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1065        has been changed.
1066    
1067    9.  Some internal refactoring has changed the processing so that the handling
1068        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1069        time (the PCRE_DOTALL option was changed this way some time ago: version
1070        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1071        which was always a bit of a fudge. It also means that there is one less
1072        argument for the match() function, which reduces its stack requirements
1073        slightly. This change also fixes an incompatibility with Perl: the pattern
1074        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1075    
1076    10. More internal refactoring has drastically reduced the number of recursive
1077        calls to match() for possessively repeated groups such as (abc)++ when
1078        using pcre_exec().
1079    
1080    11. While implementing 10, a number of bugs in the handling of groups were
1081        discovered and fixed:
1082    
1083        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1084        (a|)*(?1) gave a compile-time internal error.
1085        ((a|)+)+  did not notice that the outer group could match an empty string.
1086        (^a|^)+   was not marked as anchored.
1087        (.*a|.*)+ was not marked as matching at start or after a newline.
1088    
1089    12. Yet more internal refactoring has removed another argument from the match()
1090        function. Special calls to this function are now indicated by setting a
1091        value in a variable in the "match data" data block.
1092    
1093    13. Be more explicit in pcre_study() instead of relying on "default" for
1094        opcodes that mean there is no starting character; this means that when new
1095        ones are added and accidentally left out of pcre_study(), testing should
1096        pick them up.
1097    
1098    14. The -s option of pcretest has been documented for ages as being an old
1099        synonym of -m (show memory usage). I have changed it to mean "force study
1100        for every regex", that is, assume /S for every regex. This is similar to -i
1101        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1102        using it. It makes it easier to run collections of tests with and without
1103        study enabled, and thereby test pcre_study() more easily. All the standard
1104        tests are now run with and without -s (but some patterns can be marked as
1105        "never study" - see 20 below).
1106    
1107    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1108        restoration of the capturing data to the outer values was not happening
1109        correctly.
1110    
1111    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1112        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1113        pattern had matched an empty string, and so incorrectly returned a no
1114        match.
1115    
1116    17. There was optimizing code for the last branch of non-capturing parentheses,
1117        and also for the obeyed branch of a conditional subexpression, which used
1118        tail recursion to cut down on stack usage. Unfortunately, now that there is
1119        the possibility of (*THEN) occurring in these branches, tail recursion is
1120        no longer possible because the return has to be checked for (*THEN). These
1121        two optimizations have therefore been removed. [But see 8.20/11 above.]
1122    
1123    18. If a pattern containing \R was studied, it was assumed that \R always
1124        matched two bytes, thus causing the minimum subject length to be
1125        incorrectly computed because \R can also match just one byte.
1126    
1127    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1128        was incorrectly computed.
1129    
1130    20. If /S is present twice on a test pattern in pcretest input, it now
1131        *disables* studying, thereby overriding the use of -s on the command line
1132        (see 14 above). This is necessary for one or two tests to keep the output
1133        identical in both cases.
1134    
1135    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1136        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1137    
1138    22. When an atomic group that contained a capturing parenthesis was
1139        successfully matched, but the branch in which it appeared failed, the
1140        capturing was not being forgotten if a higher numbered group was later
1141        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1142        group 1 to "a", when in fact it should be unset. This applied to multi-
1143        branched capturing and non-capturing groups, repeated or not, and also to
1144        positive assertions (capturing in negative assertions does not happen
1145        in PCRE) and also to nested atomic groups.
1146    
1147    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1148        subject after a captured substring, to make it easier to tell which of a
1149        number of identical substrings has been captured.
1150    
1151    24. The way atomic groups are processed by pcre_exec() has been changed so that
1152        if they are repeated, backtracking one repetition now resets captured
1153        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1154        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1155        "aaa". Previously, it would have been "a". As part of this code
1156        refactoring, the way recursive calls are handled has also been changed.
1157    
1158    25. If an assertion condition captured any substrings, they were not passed
1159        back unless some other capturing happened later. For example, if
1160        (?(?=(a))a) was matched against "a", no capturing was returned.
1161    
1162    26. When studying a pattern that contained subroutine calls or assertions,
1163        the code for finding the minimum length of a possible match was handling
1164        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1165        group 1 called group 2 while simultaneously a separate group 2 called group
1166        1). A stack overflow occurred in this case. I have fixed this by limiting
1167        the recursion depth to 10.
1168    
1169    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1170        Fortmann. This supports explicit test numbers on the command line, and has
1171        argument validation and error reporting.
1172    
1173    28. An instance of \X with an unlimited repeat could fail if at any point the
1174        first character it looked at was a mark character.
1175    
1176    29. Some minor code refactoring concerning Unicode properties and scripts
1177        should reduce the stack requirement of match() slightly.
1178    
1179    30. Added the '=' option to pcretest to check the setting of unused capturing
1180        slots at the end of the pattern, which are documented as being -1, but are
1181        not included in the return count.
1182    
1183    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1184        compiled something random. Now it gives a compile-time error (as does
1185        Perl).
1186    
1187    32. A *MARK encountered during the processing of a positive assertion is now
1188        recorded and passed back (compatible with Perl).
1189    
1190    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1191        had alternative anchored branches, the search for a second match in a line
1192        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1193        matched the line "0102" twice. The same bug affected patterns that started
1194        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1195        twice.
1196    
1197    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1198        does, and because of capturing effects, quantifying parenthesized
1199        assertions may at times be useful. Quantifiers are now allowed for
1200        parenthesized assertions.
1201    
1202    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1203    
1204    36. \g was being checked for fancy things in a character class, when it should
1205        just be a literal "g".
1206    
1207    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1208        appearance of a nested POSIX class supersedes an apparent external class.
1209        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1210        unescaped square brackets may also appear as part of class names. For
1211        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1212        more like Perl. (But see 8.20/1 above.)
1213    
1214    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1215        was because it thought it was \N{name}, which is not supported).
1216    
1217    39. Add minix to OS list not supporting the -S option in pcretest.
1218    
1219    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1220        cannot analyze patterns in sufficient detail to catch mutual recursions
1221        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1222        subgroup is called recursively as a subpattern for a second time at the
1223        same position in the subject string. In previous releases this might have
1224        been caught by the recursion limit, or it might have run out of stack.
1225    
1226    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1227        happen only once. PCRE was, however incorrectly giving a compile time error
1228        "recursive call could loop indefinitely" because it cannot analyze the
1229        pattern in sufficient detail. The compile time test no longer happens when
1230        PCRE is compiling a conditional subpattern, but actual runaway loops are
1231        now caught at runtime (see 40 above).
1232    
1233    42. It seems that Perl allows any characters other than a closing parenthesis
1234        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1235        has been changed to be the same.
1236    
1237    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1238        as not to get warnings when autogen.sh is called. Also changed
1239        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1240    
1241    44. To help people who use pcregrep to scan files containing exceedingly long
1242        lines, the following changes have been made:
1243    
1244        (a) The default value of the buffer size parameter has been increased from
1245            8K to 20K. (The actual buffer used is three times this size.)
1246    
1247        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1248            PCRE is built.
1249    
1250        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1251            to be set at run time.
1252    
1253        (d) Numerical values in pcregrep options can be followed by K or M, for
1254            example --buffer-size=50K.
1255    
1256        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1257            given and the return code is set to 2.
1258    
1259    45. Add a pointer to the latest mark to the callout data block.
1260    
1261    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1262        partial match of an empty string instead of no match. This was specific to
1263        the use of ".".
1264    
1265    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1266        complete match instead of a partial match. This bug was dependent on both
1267        the PCRE_UTF8 and PCRE_DOTALL options being set.
1268    
1269    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1270        starting byte set, because \b was not being ignored.
1271    
1272    
1273    Version 8.12 15-Jan-2011
1274    ------------------------
1275    
1276    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1277        checks for such things as part of the documentation building process.
1278    
1279    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1280        --match-limit and --recursion-limit options (added for 8.11). In
1281        particular, this made one of the standard tests fail. (The integer value
1282        went into the wrong half of a long int.)
1283    
1284    3.  If the --colour option was given to pcregrep with -v (invert match), it
1285        did strange things, either producing crazy output, or crashing. It should,
1286        of course, ignore a request for colour when reporting lines that do not
1287        match.
1288    
1289    4.  Another pcregrep bug caused similar problems if --colour was specified with
1290        -M (multiline) and the pattern match finished with a line ending.
1291    
1292    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1293        matched in multiline mode, the following line was shown as part of the
1294        match. This seems wrong, so I have changed it.
1295    
1296    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1297        the check for further matches in the same line (so they could be coloured)
1298        to overrun the end of the current line. If another match was found, it was
1299        incorrectly shown (and then shown again when found in the next line).
1300    
1301    7.  If pcregrep was compiled under Windows, there was a reference to the
1302        function pcregrep_exit() before it was defined. I am assuming this was
1303        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1304        reported by a user. I've moved the definition above the reference.
1305    
1306    
1307    Version 8.11 10-Dec-2010
1308    ------------------------
1309    
1310    1.  (*THEN) was not working properly if there were untried alternatives prior
1311        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1312        backtracked to try for "b" instead of moving to the next alternative branch
1313        at the same level (in this case, to look for "c"). The Perl documentation
1314        is clear that when (*THEN) is backtracked onto, it goes to the "next
1315        alternative in the innermost enclosing group".
1316    
1317    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1318        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1319        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1320        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1321        (*THEN).
1322    
1323    3.  If \s appeared in a character class, it removed the VT character from
1324        the class, even if it had been included by some previous item, for example
1325        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1326        of \s, but is part of the POSIX "space" class.)
1327    
1328    4.  A partial match never returns an empty string (because you can always
1329        match an empty string at the end of the subject); however the checking for
1330        an empty string was starting at the "start of match" point. This has been
1331        changed to the "earliest inspected character" point, because the returned
1332        data for a partial match starts at this character. This means that, for
1333        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1334        (previously it gave "no match").
1335    
1336    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1337        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1338        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1339        has an implication that the given string is incomplete (because a partial
1340        match is preferred over a full match). For this reason, these items now
1341        give a partial match in this situation. [Aside: previously, the one case
1342        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1343        match rather than a full match, which was wrong by the old rules, but is
1344        now correct.]
1345    
1346    6.  There was a bug in the handling of #-introduced comments, recognized when
1347        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1348        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1349        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1350        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1351        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1352        places in pcre_compile().
1353    
1354    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1355        comments when looking ahead for named forward references to subpatterns,
1356        the only newline sequence it recognized was NL. It now handles newlines
1357        according to the set newline convention.
1358    
1359    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1360        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1361        cater for a lack of strerror(). These oversights have been fixed.
1362    
1363    9.  Added --match-limit and --recursion-limit to pcregrep.
1364    
1365    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1366    
1367    11. When the -o option was used, pcregrep was setting a return code of 1, even
1368        when matches were found, and --line-buffered was not being honoured.
1369    
1370    12. Added an optional parentheses number to the -o and --only-matching options
1371        of pcregrep.
1372    
1373    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1374        can match an empty string. The code to do it in pcretest and pcredemo
1375        needed fixing:
1376    
1377        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1378            only one byte after an empty string match just before CRLF (this case
1379            just got forgotten; "any" and "anycrlf" were OK).
1380    
1381        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1382            mode when an empty string match preceded an ASCII character followed by
1383            a non-ASCII character. (The code for advancing by one character rather
1384            than one byte was nonsense.)
1385    
1386        (c) The pcredemo.c sample program did not have any code at all to handle
1387            the cases when CRLF is a valid newline sequence.
1388    
1389    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1390        as a starting offset was within the subject string. There is now a new
1391        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1392        negative or greater than the length of the string. In order to test this,
1393        pcretest is extended to allow the setting of negative starting offsets.
1394    
1395    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1396        starting offset points to the beginning of a UTF-8 character was
1397        unnecessarily clumsy. I tidied it up.
1398    
1399    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1400        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1401    
1402    17. Nobody had reported that the --include_dir option, which was added in
1403        release 7.7 should have been called --include-dir (hyphen, not underscore)
1404        for compatibility with GNU grep. I have changed it to --include-dir, but
1405        left --include_dir as an undocumented synonym, and the same for
1406        --exclude-dir, though that is not available in GNU grep, at least as of
1407        release 2.5.4.
1408    
1409    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1410        characters from a string of bytes) have been redefined so as not to use
1411        loops, in order to improve performance in some environments. At the same
1412        time, I abstracted some of the common code into auxiliary macros to save
1413        repetition (this should not affect the compiled code).
1414    
1415    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1416        compile-time error is now given if \c is not followed by an ASCII
1417        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1418        different, and any byte value is allowed.)
1419    
1420    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1421        START_OPTIMIZE option, which is now allowed at compile time - but just
1422        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1423        to pcregrep and other applications that have no direct access to PCRE
1424        options. The new /Y option in pcretest sets this option when calling
1425        pcre_compile().
1426    
1427    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1428        back references. Groups containing recursive back references were forced to
1429        be atomic by that change, but in the case of named groups, the amount of
1430        memory required was incorrectly computed, leading to "Failed: internal
1431        error: code overflow". This has been fixed.
1432    
1433    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1434        pcretest.c, to avoid build problems in some Borland environments.
1435    
1436    
1437    Version 8.10 25-Jun-2010
1438    ------------------------
1439    
1440    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1441        THEN.
1442    
1443    2.  (*ACCEPT) was not working when inside an atomic group.
1444    
1445    3.  Inside a character class, \B is treated as a literal by default, but
1446        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1447        causes the error). The code is unchanged, but I tidied the documentation.
1448    
1449    4.  Inside a character class, PCRE always treated \R and \X as literals,
1450        whereas Perl faults them if its -w option is set. I have changed PCRE so
1451        that it faults them when PCRE_EXTRA is set.
1452    
1453    5.  Added support for \N, which always matches any character other than
1454        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1455    
1456    6.  When compiling pcregrep with newer versions of gcc which may have
1457        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1458        declared with attribute warn_unused_result" were given. Just casting the
1459        result to (void) does not stop the warnings; a more elaborate fudge is
1460        needed. I've used a macro to implement this.
1461    
1462    7.  Minor change to pcretest.c to avoid a compiler warning.
1463    
1464    8.  Added four artifical Unicode properties to help with an option to make
1465        \s etc use properties (see next item). The new properties are: Xan
1466        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1467    
1468    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1469        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1470        this option. Modified pcretest to add /W to test this facility. Added
1471        REG_UCP to make it available via the POSIX interface.
1472    
1473    10. Added --line-buffered to pcregrep.
1474    
1475    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1476        studied, and the match started with a letter with a code point greater than
1477        127 whose first byte was different to the first byte of the other case of
1478        the letter, the other case of this starting letter was not recognized
1479        (#976).
1480    
1481    12. If a pattern that was studied started with a repeated Unicode property
1482        test, for example, \p{Nd}+, there was the theoretical possibility of
1483        setting up an incorrect bitmap of starting bytes, but fortunately it could
1484        not have actually happened in practice until change 8 above was made (it
1485        added property types that matched character-matching opcodes).
1486    
1487    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1488        possible starting bytes for non-anchored patterns.
1489    
1490    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1491        \R, and also a number of cases that involve Unicode properties, both
1492        explicit and implicit when PCRE_UCP is set.
1493    
1494    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1495        input, it could crash or give wrong results if characters with values
1496        greater than 0xc0 were present in the subject string. (Detail: it assumed
1497        UTF-8 input when processing these items.)
1498    
1499    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1500        size_t is 64-bit (#991).
1501    
1502    17. Added a check for running out of memory when PCRE is compiled with
1503        --disable-stack-for-recursion (#990).
1504    
1505    18. If the last data line in a file for pcretest does not have a newline on
1506        the end, a newline was missing in the output.
1507    
1508    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1509        less than 128) in its various bitmaps. However, there is a facility for
1510        generating tables according to the current locale when PCRE is compiled. It
1511        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1512        characters, are recognized by isspace() and therefore were getting set in
1513        these tables, and indeed these tables seem to approximate to ISO 8859. This
1514        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1515        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1516        which of course cannot start UTF-8 characters. I have changed the code so
1517        that only real ASCII characters (less than 128) and the correct starting
1518        bytes for UTF-8 encodings are set for characters greater than 127 when in
1519        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1520        altogether.)
1521    
1522    20. Added the /T option to pcretest so as to be able to run tests with non-
1523        standard character tables, thus making it possible to include the tests
1524        used for 19 above in the standard set of tests.
1525    
1526    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1527        reference to a subpattern the other side of a comment that contains an
1528        opening parenthesis caused either an internal compiling error, or a
1529        reference to the wrong subpattern.
1530    
1531    
1532    Version 8.02 19-Mar-2010
1533    ------------------------
1534    
1535    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1536    
1537    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1538        configured.
1539    
1540    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1541        original author of that file, following a query about its status.
1542    
1543    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1544        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1545    
1546    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1547        quantifier applied to a forward-referencing subroutine call, could compile
1548        incorrect code or give the error "internal error: previously-checked
1549        referenced subpattern not found".
1550    
1551    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1552        variables to point to external functions. For these systems, therefore,
1553        pcre_malloc etc. are now initialized to local functions that call the
1554        relevant global functions.
1555    
1556    7.  There were two entries missing in the vectors called coptable and poptable
1557        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1558        I've fixed the data, and added a kludgy way of testing at compile time that
1559        the lengths are correct (equal to the number of opcodes).
1560    
1561    8.  Following on from 7, I added a similar kludge to check the length of the
1562        eint vector in pcreposix.c.
1563    
1564    9.  Error texts for pcre_compile() are held as one long string to avoid too
1565        much relocation at load time. To find a text, the string is searched,
1566        counting zeros. There was no check for running off the end of the string,
1567        which could happen if a new error number was added without updating the
1568        string.
1569    
1570    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1571    
1572    11. \K was not working if it appeared in an atomic group or in a group that
1573        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1574        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1575        the assertion is positive, but not if it is negative.
1576    
1577    12. Change 11 fortuitously reduced the size of the stack frame used in the
1578        "match()" function of pcre_exec.c by one pointer. Forthcoming
1579        implementation of support for (*MARK) will need an extra pointer on the
1580        stack; I have reserved it now, so that the stack frame size does not
1581        decrease.
1582    
1583    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1584        item in branch that calls a recursion is a subroutine call - as in the
1585        second branch in the above example - was incorrectly given the compile-
1586        time error "recursive call could loop indefinitely" because pcre_compile()
1587        was not correctly checking the subroutine for matching a non-empty string.
1588    
1589    14. The checks for overrunning compiling workspace could trigger after an
1590        overrun had occurred. This is a "should never occur" error, but it can be
1591        triggered by pathological patterns such as hundreds of nested parentheses.
1592        The checks now trigger 100 bytes before the end of the workspace.
1593    
1594    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1595    
1596    
1597    Version 8.01 19-Jan-2010
1598    ------------------------
1599    
1600    1.  If a pattern contained a conditional subpattern with only one branch (in
1601        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1602        computed the wrong minimum data length (which is of course zero for such
1603        subpatterns). This could cause incorrect "no match" results.
1604    
1605    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1606        the pattern is reset in the first branch, pcre_compile() failed with
1607        "internal error: code overflow at offset...". This happened only when
1608        the reset was to the original external option setting. (An optimization
1609        abstracts leading options settings into an external setting, which was the
1610        cause of this.)
1611    
1612    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1613        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1614        assertion pattern did not match (meaning that the assertion was true), it
1615        was incorrectly treated as false if the SKIP had been reached during the
1616        matching. This also applied to assertions used as conditions.
1617    
1618    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1619        assertion subpattern, including such a pattern used as a condition,
1620        unpredictable results occurred, instead of the error return
1621        PCRE_ERROR_DFA_UITEM.
1622    
1623    5.  The C++ GlobalReplace function was not working like Perl for the special
1624        situation when an empty string is matched. It now does the fancy magic
1625        stuff that is necessary.
1626    
1627    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1628        removed. (These were left over from very, very early versions of PCRE.)
1629    
1630    7.  Some cosmetic changes to the code to make life easier when compiling it
1631        as part of something else:
1632    
1633        (a) Change DEBUG to PCRE_DEBUG.
1634    
1635        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1636            called "current" as "current_branch", to prevent a collision with the
1637            Linux macro when compiled as a kernel module.
1638    
1639        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1640            prevent a collision with the Linux macro when compiled as a kernel
1641            module.
1642    
1643    8.  In pcre_compile() there are some checks for integer overflows that used to
1644        cast potentially large values to (double). This has been changed to that
1645        when building, a check for int64_t is made, and if it is found, it is used
1646        instead, thus avoiding the use of floating point arithmetic. (There is no
1647        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1648        double.
1649    
1650    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1651        2005 (difference between two addresses compared to an unsigned value).
1652    
1653    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1654        custom one, because of the following reported problem in Windows:
1655    
1656          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1657              under Win32.
1658          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1659              therefore missing the function definition.
1660          - The compiler thus generates a "C" signature for the test function.
1661          - The linker fails to find the "C" function.
1662          - PCRE fails to configure if asked to do so against libbz2.
1663    
1664    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1665        messages were output:
1666    
1667          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1668          rerunning libtoolize, to keep the correct libtool macros in-tree.
1669          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1670    
1671        I have done both of these things.
1672    
1673    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1674        most of the time, it *can* run out if it is given a pattern that contains a
1675        runaway infinite recursion. I updated the discussion in the pcrestack man
1676        page.
1677    
1678    13. Now that we have gone to the x.xx style of version numbers, the minor
1679        version may start with zero. Using 08 or 09 is a bad idea because users
1680        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1681        interpreted as invalid octal numbers. I've updated the previous comment in
1682        configure.ac, and also added a check that gives an error if 08 or 09 are
1683        used.
1684    
1685    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1686        causing partial matching to fail when the end of the subject matched \W
1687        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1688    
1689    15. There were some discrepancies between the declarations in pcre_internal.h
1690        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1691        their definitions. The declarations used "const uschar *" and the
1692        definitions used USPTR. Even though USPTR is normally defined as "const
1693        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1694        reported that: "This difference in casting confuses some C++ compilers, for
1695        example, SunCC recognizes above declarations as different functions and
1696        generates broken code for hbpcre." I have changed the declarations to use
1697        USPTR.
1698    
1699    16. GNU libtool is named differently on some systems. The autogen.sh script now
1700        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1701        (FreeBSD).
1702    
1703    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1704        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1705        comment: "Figure out how to create a longlong from a string: strtoll and
1706        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1707        instance, but it only takes 2 args instead of 3!"
1708    
1709    18. A subtle bug concerned with back references has been fixed by a change of
1710        specification, with a corresponding code fix. A pattern such as
1711        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1712        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1713        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1714        same bug. Such groups have to be quantified to be useful, or contained
1715        inside another quantified group. (If there's no repetition, the reference
1716        can never match.) The problem arises because, having left the group and
1717        moved on to the rest of the pattern, a later failure that backtracks into
1718        the group uses the captured value from the final iteration of the group
1719        rather than the correct earlier one. I have fixed this in PCRE by forcing
1720        any group that contains a reference to itself to be an atomic group; that
1721        is, there cannot be any backtracking into it once it has completed. This is
1722        similar to recursive and subroutine calls.
1723    
1724    
1725    Version 8.00 19-Oct-09
1726  ----------------------  ----------------------
1727    
1728  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
1729      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
1730      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
1731      error.      error.
1732    
1733  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1734      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1735      in a Windows environment.      in a Windows environment.
1736    
1737  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
1738      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
1739      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
1740      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
1741      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
1742      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
1743      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
1744    
1745  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
1746      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
1747      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
1748      the old behaviour.      the old behaviour.
1749    
1750  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
1751      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
1752      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
1753      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
1754    
1755  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
1756      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1757    
1758  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1759      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
1760      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
1761      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
1762      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
1763      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
1764    
1765  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1766      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
1767      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1768      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1769      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
1770      result.      result.
1771    
1772  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
1773      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
1774      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
1775      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
1776      for the match and the offset of the end of the subject are set in them when      for the match and the offset of the end of the subject are set in them when
1777      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
1778    
1779  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1780      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
1781      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1782      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
1783      pcre_exec().  
1784    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1785  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
1786      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
1787      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1788      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
1789      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
1790      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
1791      final character ended with (*FAIL).  
   
1792  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1793      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
1794      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
1795      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
1796      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
1797      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
1798    
1799  13. The string returned by pcre_dfa_exec() after a partial match has been  13. The string returned by pcre_dfa_exec() after a partial match has been
1800      changed so that it starts at the first inspected character rather than the      changed so that it starts at the first inspected character rather than the
1801      first character of the match. This makes a difference only if the pattern      first character of the match. This makes a difference only if the pattern
1802      starts with a lookbehind assertion or \b or \B (\K is not supported by      starts with a lookbehind assertion or \b or \B (\K is not supported by
1803      pcre_dfa_exec()). It's an incompatible change, but it makes the two      pcre_dfa_exec()). It's an incompatible change, but it makes the two
1804      matching functions compatible, and I think it's the right thing to do.      matching functions compatible, and I think it's the right thing to do.
1805    
1806  14. Added a pcredemo man page, created automatically from the pcredemo.c file,  14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1807      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
1808      PCRE has not been installed from source.      PCRE has not been installed from source.
1809    
1810  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1811      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1812      library.      library.
1813    
1814  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1815      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1816      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
1817      these options useful.      these options useful.
1818    
1819  17. If a caller to the POSIX matching function regexec() passes a non-zero  17. If a caller to the POSIX matching function regexec() passes a non-zero
1820      value for \fInmatch\fP with a NULL value for \fIpmatch\fP, the value of      value for nmatch with a NULL value for pmatch, the value of
1821      \fInmatch\fP is forced to zero.      nmatch is forced to zero.
1822    
1823    18. RunGrepTest did not have a test for the availability of the -u option of
1824        the diff command, as RunTest does. It now checks in the same way as
1825        RunTest, and also checks for the -b option.
1826    
1827    19. If an odd number of negated classes containing just a single character
1828        interposed, within parentheses, between a forward reference to a named
1829        subpattern and the definition of the subpattern, compilation crashed with
1830        an internal error, complaining that it could not find the referenced
1831        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1832        [The bug was that it was starting one character too far in when skipping
1833        over the character class, thus treating the ] as data rather than
1834        terminating the class. This meant it could skip too much.]
1835    
1836    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1837        /g option in pcretest when the pattern contains \K, which makes it possible
1838        to have an empty string match not at the start, even when the pattern is
1839        anchored. Updated pcretest and pcredemo to use this option.
1840    
1841    21. If the maximum number of capturing subpatterns in a recursion was greater
1842        than the maximum at the outer level, the higher number was returned, but
1843        with unset values at the outer level. The correct (outer level) value is
1844        now given.
1845    
1846    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1847        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1848        make it do so. The string so far is captured, making this feature
1849        compatible with Perl.
1850    
1851    23. The tests have been re-organized, adding tests 11 and 12, to make it
1852        possible to check the Perl 5.10 features against Perl 5.10.
1853    
1854    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1855        pattern matches a fixed length string. PCRE did not allow this; now it
1856        does. Neither allows recursion.
1857    
1858    25. I finally figured out how to implement a request to provide the minimum
1859        length of subject string that was needed in order to match a given pattern.
1860        (It was back references and recursion that I had previously got hung up
1861        on.) This code has now been added to pcre_study(); it finds a lower bound
1862        to the length of subject needed. It is not necessarily the greatest lower
1863        bound, but using it to avoid searching strings that are too short does give
1864        some useful speed-ups. The value is available to calling programs via
1865        pcre_fullinfo().
1866    
1867    26. While implementing 25, I discovered to my embarrassment that pcretest had
1868        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1869        study optimizations had never been tested with that matching function.
1870        Oops. What is worse, even when it was passed study data, there was a bug in
1871        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1872        were also very few tests of studied patterns with pcre_dfa_exec().
1873    
1874    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1875        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1876        on the other side of the coin, they are no longer allowed to have different
1877        names, because these cannot be distinguished in PCRE, and this has caused
1878        confusion. (This is a difference from Perl.)
1879    
1880    28. When duplicate subpattern names are present (necessarily with different
1881        numbers, as required by 27 above), and a test is made by name in a
1882        conditional pattern, either for a subpattern having been matched, or for
1883        recursion in such a pattern, all the associated numbered subpatterns are
1884        tested, and the overall condition is true if the condition is true for any
1885        one of them. This is the way Perl works, and is also more like the way
1886        testing by number works.
1887    
1888    
1889  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1890  ---------------------  ---------------------
# Line 135  Version 7.9 11-Apr-09 Line 1920  Version 7.9 11-Apr-09
1920  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
1921      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
1922      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1923      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1924        8.33.]
1925    
1926  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
1927      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 378  Version 7.7 07-May-08 Line 2164  Version 7.7 07-May-08
2164      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2165      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2166      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2167      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2168      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2169      was subsequently set up correctly.)      was subsequently set up correctly.)
2170    

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