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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.10 03-Jun-2010  Version 8.35-RC1 14-March-2014
5    ------------------------------
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.
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.
15    3.  Got rid of some compiler warnings for potentially uninitialized variables
16        that show up only when compiled with -O2.
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.
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.
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.
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.
40    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
41        to the export list in Makefile.am (they were accidentally omitted from the
42        8.34 tarball).
44    9.  The informational output from pcretest used the phrase "starting byte set"
45        which is inappropriate for the 16-bit and 32-bit libraries. As the output
46        for "first char" and "need char" really means "non-UTF-char", I've changed
47        "byte" to "char", and slightly reworded the output. The documentation about
48        these values has also been (I hope) clarified.
50    10. Another JIT related optimization: use table jumps for selecting the correct
51        backtracking path, when more than four alternatives are present inside a
52        bracket.
54    11. Empty match is not possible, when the minimum length is greater than zero,
55        and there is no \K in the pattern. JIT should avoid empty match checks in
56        such cases.
58    12. In a caseless character class with UCP support, when a character with more
59        than one alternative case was not the first character of a range, not all
60        the alternative cases were added to the class. For example, s and \x{17f}
61        are both alternative cases for S: the class [RST] was handled correctly,
62        but [R-T] was not.
64    13. The configure.ac file always checked for pthread support when JIT was
65        enabled. This is not used in Windows, so I have put this test inside a
66        check for the presence of windows.h (which was already tested for).
68    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
69        The algorithm provides a way to skip certain starting offsets, and usually
70        faster than linear prefix searches.
72    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
73        as for 'fr_FR' and 'french'. For some reason, however, it then used the
74        Windows-specific input and output files, which have 'french' screwed in.
75        So this could never have worked. One of the problems with locales is that
76        they aren't always the same. I have now updated RunTest so that it checks
77        the output of the locale test (test 3) against three different output
78        files, and it allows the test to pass if any one of them matches. With luck
79        this should make the test pass on some versions of Solaris where it was
80        failing. Because of the uncertainty, the script did not used to stop if
81        test 3 failed; it now does. If further versions of a French locale ever
82        come to light, they can now easily be added.
84    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
85        there was a message during ./configure, but it did not stop. This now
86        provokes an error. The invalid example in README has been corrected.
87        If a value less than the minimum is given, the minimum value has always
88        been used, but now a warning is given.
90    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
91        was a bug in the test system, which is now fixed. Also, the list of various
92        configurations that are tested for each release did not have one with both
93        16/32 bits and --enable-bar-anycrlf. It now does.
95    18. pcretest was missing "-C bsr" for displaying the \R default setting.
97    19. Little endian PowerPC systems are supported now by the JIT compiler.
99    20. The fast forward newline mechanism could enter to an infinite loop on
100        certain invalid UTF-8 input. Although we don't support these cases
101        this issue can be fixed by a performance optimization.
103    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
104        not take account if existing stack usage. There is now a new global
105        variable called pcre_stack_guard that can be set to point to an external
106        function to check stack availability. It is called at the start of
107        processing every parenthesized group.
109    22. A typo in the code meant that in ungreedy mode the max/min qualifier
110        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
111        not match "ab".
113    23. When UTF was disabled, the JIT program reported some incorrect compile
114        errors. These messages are silenced now.
116    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
117        compiler.
120    Version 8.34 15-December-2013
121    -----------------------------
123    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
124        executable memory. Patch inspired by Carsten Klein.
126    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
127        this macro is never tested and has no effect, because the work to support
128        coverage involves only compiling and linking options and special targets in
129        the Makefile. The comment in config.h implied that defining the macro would
130        enable coverage support, which is totally false. There was also support for
131        setting this macro in the CMake files (my fault, I just copied it from
132        configure). SUPPORT_GCOV has now been removed.
134    3.  Make a small performance improvement in strlen16() and strlen32() in
135        pcretest.
137    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
138        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
139        these cases). There was also one in pcretest.c.
141    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
143    6.  In UTF mode, the code for checking whether a group could match an empty
144        string (which is used for indefinitely repeated groups to allow for
145        breaking an infinite loop) was broken when the group contained a repeated
146        negated single-character class with a character that occupied more than one
147        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
148        UTF-8 mode). The effect was undefined: the group might or might not be
149        deemed as matching an empty string, or the program might have crashed.
151    7.  The code for checking whether a group could match an empty string was not
152        recognizing that \h, \H, \v, \V, and \R must match a character.
154    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
155        an empty string. If it can, pcretest shows this in its information output.
157    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
158        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
159        matched by pcre_exec() without using JIT:
161        (a) If the rest of the pattern did not match after a maximal run of
162            grapheme clusters, the code for backing up to try with fewer of them
163            did not always back up over a full grapheme when characters that do not
164            have the modifier quality were involved, e.g. Hangul syllables.
166        (b) If the match point in a subject started with modifier character, and
167            there was no match, the code could incorrectly back up beyond the match
168            point, and potentially beyond the first character in the subject,
169            leading to a segfault or an incorrect match result.
171    10. A conditional group with an assertion condition could lead to PCRE
172        recording an incorrect first data item for a match if no other first data
173        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
174        first data item, and therefore matched "ca" after "c" instead of at the
175        start.
177    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
178        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
180    12. The source of pcregrep now includes z/OS-specific code so that it can be
181        compiled for z/OS as part of the special z/OS distribution.
183    13. Added the -T and -TM options to pcretest.
185    14. The code in pcre_compile.c for creating the table of named capturing groups
186        has been refactored. Instead of creating the table dynamically during the
187        actual compiling pass, the information is remembered during the pre-compile
188        pass (on the stack unless there are more than 20 named groups, in which
189        case malloc() is used) and the whole table is created before the actual
190        compile happens. This has simplified the code (it is now nearly 150 lines
191        shorter) and prepared the way for better handling of references to groups
192        with duplicate names.
194    15. A back reference to a named subpattern when there is more than one of the
195        same name now checks them in the order in which they appear in the pattern.
196        The first one that is set is used for the reference. Previously only the
197        first one was inspected. This change makes PCRE more compatible with Perl.
199    16. Unicode character properties were updated from Unicode 6.3.0.
201    17. The compile-time code for auto-possessification has been refactored, based
202        on a patch by Zoltan Herczeg. It now happens after instead of during
203        compilation. The code is cleaner, and more cases are handled. The option
204        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
205        options in pcretest are provided to set it. It can also be set by
206        (*NO_AUTO_POSSESS) at the start of a pattern.
208    18. The character VT has been added to the default ("C" locale) set of
209        characters that match \s and are generally treated as white space,
210        following this same change in Perl 5.18. There is now no difference between
211        "Perl space" and "POSIX space". Whether VT is treated as white space in
212        other locales depends on the locale.
214    19. The code for checking named groups as conditions, either for being set or
215        for being recursed, has been refactored (this is related to 14 and 15
216        above). Processing unduplicated named groups should now be as fast at
217        numerical groups, and processing duplicated groups should be faster than
218        before.
220    20. Two patches to the CMake build system, by Alexander Barkov:
222          (1) Replace the "source" command by "." in CMakeLists.txt because
223              "source" is a bash-ism.
225          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
226              without these the CMake build does not work on Solaris.
228    21. Perl has changed its handling of \8 and \9. If there is no previously
229        encountered capturing group of those numbers, they are treated as the
230        literal characters 8 and 9 instead of a binary zero followed by the
231        literals. PCRE now does the same.
233    22. Following Perl, added \o{} to specify codepoints in octal, making it
234        possible to specify values greater than 0777 and also making them
235        unambiguous.
237    23. Perl now gives an error for missing closing braces after \x{... instead of
238        treating the string as literal. PCRE now does the same.
240    24. RunTest used to grumble if an inappropriate test was selected explicitly,
241        but just skip it when running all tests. This make it awkward to run ranges
242        of tests when one of them was inappropriate. Now it just skips any
243        inappropriate tests, as it always did when running all tests.
245    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
246        character types such as \d or \w, too many callouts were inserted, and the
247        data that they returned was rubbish.
249    26. In UCP mode, \s was not matching two of the characters that Perl matches,
250        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
251        were matched by \h. The code has now been refactored so that the lists of
252        the horizontal and vertical whitespace characters used for \h and \v (which
253        are defined only in one place) are now also used for \s.
255    27. Add JIT support for the 64 bit TileGX architecture.
256        Patch by Jiong Wang (Tilera Corporation).
258    28. Possessive quantifiers for classes (both explicit and automatically
259        generated) now use special opcodes instead of wrapping in ONCE brackets.
261    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
262        (because it's meaningless), this was not happening when PCRE_CASELESS was
263        set. Not wrong, but inefficient.
265    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
266        properties for \w, \d, etc) is present in a test regex. Otherwise if the
267        test contains no characters greater than 255, Perl doesn't realise it
268        should be using Unicode semantics.
270    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
271        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
272        does in Unicode mode.
274    32. Added the "forbid" facility to pcretest so that putting tests into the
275        wrong test files can sometimes be quickly detected.
277    33. There is now a limit (default 250) on the depth of nesting of parentheses.
278        This limit is imposed to control the amount of system stack used at compile
279        time. It can be changed at build time by --with-parens-nest-limit=xxx or
280        the equivalent in CMake.
282    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
283        errors. Perl warns for these when in warning mode, but PCRE has no facility
284        for giving warnings.
286    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
287        However, this was not working for (?!) because it is optimized to (*FAIL),
288        for which PCRE does not allow quantifiers. The optimization is now disabled
289        when a quantifier follows (?!). I can't see any use for this, but it makes
290        things uniform.
292    36. Perl no longer allows group names to start with digits, so I have made this
293        change also in PCRE. It simplifies the code a bit.
295    37. In extended mode, Perl ignores spaces before a + that indicates a
296        possessive quantifier. PCRE allowed a space before the quantifier, but not
297        before the possessive +. It now does.
299    38. The use of \K (reset reported match start) within a repeated possessive
300        group such as (a\Kb)*+ was not working.
302    40. Document that the same character tables must be used at compile time and
303        run time, and that the facility to pass tables to pcre_exec() and
304        pcre_dfa_exec() is for use only with saved/restored patterns.
306    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
307        features for Builds with MSVC:
309        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
310           builds). The .rc files can be used to set FileDescription and many other
311           attributes.
313        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
314           This allows higher-level build scripts which want .pdb files to avoid
315           hard-coding the exact files needed."
317    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
318        mean "start of word" and "end of word", respectively, as a transition aid.
320    43. A minimizing repeat of a class containing codepoints greater than 255 in
321        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
322        compiled to use the heap for recursion.
324    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
325        is configured.
328    Version 8.33 28-May-2013
329    ------------------------
331    1.  Added 'U' to some constants that are compared to unsigned integers, to
332        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
333        variables that are added to signed variables, to ensure the result is
334        signed and can be negated.
336    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
337        CMake config files.
339    3.  Revise the creation of config.h.generic so that all boolean macros are
340        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
341        overriding via -D on the command line possible.
343    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
344        to unsigned int is reported to make a quite noticeable speed difference in
345        a specific Windows environment. Testing on Linux did also appear to show
346        some benefit (and it is clearly not harmful). Also fixed the definition of
347        Xop which should be unsigned.
349    5.  Related to (4), changing the definition of the intermediate variable cc
350        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
351        improvements.
353    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
354        unnecessary spaces.
356    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
357        and later.
359    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
361    9.  Optimizing fast_forward_start_bits in JIT.
363    10. Adding support for callouts in JIT, and fixing some issues revealed
364        during this work. Namely:
366        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
368        (b) Minimum length was not checked before the matching is started.
370    11. The value of capture_last that is passed to callouts was incorrect in some
371        cases when there was a capture on one path that was subsequently abandoned
372        after a backtrack. Also, the capture_last value is now reset after a
373        recursion, since all captures are also reset in this case.
375    12. The interpreter no longer returns the "too many substrings" error in the
376        case when an overflowing capture is in a branch that is subsequently
377        abandoned after a backtrack.
379    13. In the pathological case when an offset vector of size 2 is used, pcretest
380        now prints out the matched string after a yield of 0 or 1.
382    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
383        Only supported by the JIT compiler at the moment.
385    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
387    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
388        offset of the starting point of the matching process, provided the offsets
389        vector is large enough.
391    17. The \A escape now records a lookbehind value of 1, though its execution
392        does not actually inspect the previous character. This is to ensure that,
393        in partial multi-segment matching, at least one character from the old
394        segment is retained when a new segment is processed. Otherwise, if there
395        are no lookbehinds in the pattern, \A might match incorrectly at the start
396        of a new segment.
398    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
400    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
401        gives some modest performance improvement in 8-bit mode.
403    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
404        be expressed in certain programming languages using Universal Character
405        Names.
407    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
408        which points out that "non characters" are not "characters that may not
409        appear in Unicode strings" but rather "characters that are reserved for
410        internal use and have only local meaning".
412    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
413        there was a conditional group that depended on an assertion, if the
414        assertion was false, the callout that immediately followed the alternation
415        in the condition was skipped when pcre_exec() was used for matching.
417    23. Allow an explicit callout to be inserted before an assertion that is the
418        condition for a conditional group, for compatibility with automatic
419        callouts, which always insert a callout at this point.
421    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
422        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
424    25. (*PRUNE) is now supported by the JIT compiler.
426    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
428    27. Fix the case where there are two or more SKIPs with arguments that may be
429        ignored.
431    28. (*SKIP) is now supported by the JIT compiler.
433    29. (*THEN) is now supported by the JIT compiler.
435    30. Update RunTest with additional test selector options.
437    31. The way PCRE handles backtracking verbs has been changed in two ways.
439        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
440        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
441        backtracking. In some cases this makes it more Perl-compatible, but Perl's
442        rather obscure rules do not always do the same thing.
444        (2) Previously, backtracking verbs were confined within assertions. This is
445        no longer the case for positive assertions, except for (*ACCEPT). Again,
446        this sometimes improves Perl compatibility, and sometimes does not.
448    32. A number of tests that were in test 2 because Perl did things differently
449        have been moved to test 1, because either Perl or PCRE has changed, and
450        these tests are now compatible.
452    32. Backtracking control verbs are now handled in the same way in JIT and
453        interpreter.
455    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
456        contained a forward subroutine reference caused a compile error.
458    34. Auto-detect and optimize limited repetitions in JIT.
460    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
461        blocking (*UTF) etc.
463    36. In the interpreter, maximizing pattern repetitions for characters and
464        character types now use tail recursion, which reduces stack usage.
466    37. The value of the max lookbehind was not correctly preserved if a compiled
467        and saved regex was reloaded on a host of different endianness.
469    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
470        of the compiled pattern block, expand the flags field from 16 to 32 bits
471        because it was almost full.
473    39. Try madvise first before posix_madvise.
475    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
476        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
477        original change locked out all matches of empty strings. This has been
478        changed so that one match of an empty string per line is recognized.
479        Subsequent searches on the same line (for colouring or for --only-matching,
480        for example) do not recognize empty strings.
482    41. Applied a user patch to fix a number of spelling mistakes in comments.
484    42. Data lines longer than 65536 caused pcretest to crash.
486    43. Clarified the data type for length and startoffset arguments for pcre_exec
487        and pcre_dfa_exec in the function-specific man pages, where they were
488        explicitly stated to be in bytes, never having been updated. I also added
489        some clarification to the pcreapi man page.
491    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
492        a segmentation fault.
495    Version 8.32 30-November-2012
496    -----------------------------
498    1.  Improved JIT compiler optimizations for first character search and single
499        character iterators.
501    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
502        Patch by Daniel Richard G.
504    3.  Single character iterator optimizations in the JIT compiler.
506    4.  Improved JIT compiler optimizations for character ranges.
508    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
509        Reported by Giuseppe D'Angelo.
511    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
512        of a line, was being set incorrectly in cases where .* appeared inside
513        atomic brackets at the start of a pattern, or where there was a subsequent
514        *PRUNE or *SKIP.
516    7.  Improved instruction cache flush for POWER/PowerPC.
517        Patch by Daniel Richard G.
519    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
520        grep:
522        (a) There is now no limit to the number of patterns to be matched.
524        (b) An error is given if a pattern is too long.
526        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
527            are now supported.
529        (d) --exclude-from and --include-from (multiple use) have been added.
531        (e) Exclusions and inclusions now apply to all files and directories, not
532            just to those obtained from scanning a directory recursively.
534        (f) Multiple uses of -f and --file-list are now supported.
536        (g) In a Windows environment, the default for -d has been changed from
537            "read" (the GNU grep default) to "skip", because otherwise the presence
538            of a directory in the file list provokes an error.
540        (h) The documentation has been revised and clarified in places.
542    9.  Improve the matching speed of capturing brackets.
544    10. Changed the meaning of \X so that it now matches a Unicode extended
545        grapheme cluster.
547    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
548        out POSIX threads when JIT support is configured.
550    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
552    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
553        structure could go wrong in environments where size_t is not the same size
554        as int.
556    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
557        set.
559    15. The EBCDIC support had decayed; later updates to the code had included
560        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
561        general tidy up of EBCDIC-related issues, and the documentation was also
562        not quite right. There is now a test that can be run on ASCII systems to
563        check some of the EBCDIC-related things (but is it not a full test).
565    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
566        in a small tidy to the code.
568    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
570    18. If the --only-matching (-o) option in pcregrep is specified multiple
571        times, each one causes appropriate output. For example, -o1 -o2 outputs the
572        substrings matched by the 1st and 2nd capturing parentheses. A separating
573        string can be specified by --om-separator (default empty).
575    19. Improving the first n character searches.
577    20. Turn case lists for horizontal and vertical white space into macros so that
578        they are defined only once.
580    21. This set of changes together give more compatible Unicode case-folding
581        behaviour for characters that have more than one other case when UCP
582        support is available.
584        (a) The Unicode property table now has offsets into a new table of sets of
585            three or more characters that are case-equivalent. The MultiStage2.py
586            script that generates these tables (the pcre_ucd.c file) now scans
587            CaseFolding.txt instead of UnicodeData.txt for character case
588            information.
590        (b) The code for adding characters or ranges of characters to a character
591            class has been abstracted into a generalized function that also handles
592            case-independence. In UTF-mode with UCP support, this uses the new data
593            to handle characters with more than one other case.
595        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
596            whose other case is greater than 256 are now correctly matched
597            caselessly. Previously, the high codepoint matched the low one, but not
598            vice versa.
600        (d) The processing of \h, \H, \v, and \ in character classes now makes use
601            of the new class addition function, using character lists defined as
602            macros alongside the case definitions of 20 above.
604        (e) Caseless back references now work with characters that have more than
605            one other case.
607        (f) General caseless matching of characters with more than one other case
608            is supported.
610    22. Unicode character properties were updated from Unicode 6.2.0
612    23. Improved CMake support under Windows. Patch by Daniel Richard G.
614    24. Add support for 32-bit character strings, and UTF-32
616    25. Major JIT compiler update (code refactoring and bugfixing).
617        Experimental Sparc 32 support is added.
619    26. Applied a modified version of Daniel Richard G's patch to create
620        pcre.h.generic and config.h.generic by "make" instead of in the
621        PrepareRelease script.
623    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
624        pcre_compile.c when checking for a zero character.
626    28. Introducing a native interface for JIT. Through this interface, the compiled
627        machine code can be directly executed. The purpose of this interface is to
628        provide fast pattern matching, so several sanity checks are not performed.
629        However, feature tests are still performed. The new interface provides
630        1.4x speedup compared to the old one.
632    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
633        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
634        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
636    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
637        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
638        the "old" RFC 2279). Instead, it ended up passing a negative length to
639        pcre_exec().
641    31. Add support for GCC's visibility feature to hide internal functions.
643    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
644        "unknown -C option" after outputting 0 or 1.
646    33. There is now support for generating a code coverage report for the test
647        suite in environments where gcc is the compiler and lcov is installed. This
648        is mainly for the benefit of the developers.
650    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
651        unaddressable using valgrind annotations, allowing valgrind to detect
652        invalid memory accesses. This is mainly for the benefit of the developers.
654    25. (*UTF) can now be used to start a pattern in any of the three libraries.
656    26. Give configure error if --enable-cpp but no C++ compiler found.
659    Version 8.31 06-July-2012
660    -------------------------
662    1.  Fixing a wrong JIT test case and some compiler warnings.
664    2.  Removed a bashism from the RunTest script.
666    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
667        to unsigned type, result still unsigned" that was given by an MS compiler
668        on encountering the code "-sizeof(xxx)".
670    4.  Partial matching support is added to the JIT compiler.
672    5.  Fixed several bugs concerned with partial matching of items that consist
673        of more than one character:
675        (a) /^(..)\1/ did not partially match "aba" because checking references was
676            done on an "all or nothing" basis. This also applied to repeated
677            references.
679        (b) \R did not give a hard partial match if \r was found at the end of the
680            subject.
682        (c) \X did not give a hard partial match after matching one or more
683            characters at the end of the subject.
685        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
686            a partial match for the string "\r".
688        (e) When newline was set to CRLF, the metacharacter "." did not recognize
689            a partial match for a CR character at the end of the subject string.
691    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
692        running pcretest, the text "(JIT)" added to the output whenever JIT is
693        actually used to run the match.
695    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
696        or /S+[+] with a digit between 1 and 7.
698    8.  OP_NOT now supports any UTF character not just single-byte ones.
700    9.  (*MARK) control verb is now supported by the JIT compiler.
702    10. The command "./RunTest list" lists the available tests without actually
703        running any of them. (Because I keep forgetting what they all are.)
707    12. Applied a (slightly modified) user-supplied patch that improves performance
708        when the heap is used for recursion (compiled with --disable-stack-for-
709        recursion). Instead of malloc and free for each heap frame each time a
710        logical recursion happens, frames are retained on a chain and re-used where
711        possible. This sometimes gives as much as 30% improvement.
713    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
714        call.
716    14. As documented, (*COMMIT) is now confined to within a positive assertion.
718    15. It is now possible to link pcretest with libedit as an alternative to
719        libreadline.
721    16. (*COMMIT) control verb is now supported by the JIT compiler.
723    17. The Unicode data tables have been updated to Unicode 6.1.0.
725    18. Added --file-list option to pcregrep.
727    19. Added binary file support to pcregrep, including the -a, --binary-files,
728        -I, and --text options.
730    20. The madvise function is renamed for posix_madvise for QNX compatibility
731        reasons. Fixed by Giuseppe D'Angelo.
733    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
735    22. Changed the option for creating symbolic links for 16-bit man pages from
736        -s to -sf so that re-installing does not cause issues.
738    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
740    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
741        matches in certain environments (the workspace was not being correctly
742        retained). Also added to pcre_dfa_exec() a simple plausibility check on
743        some of the workspace data at the beginning of a restart.
745    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
746        was not doing so when it should - probably a typo introduced by SVN 528
747        (change 8.10/14).
749    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
750        \w+ when the character tables indicated that \x{c4} was a word character.
751        There were several related cases, all because the tests for doing a table
752        lookup were testing for characters less than 127 instead of 255.
754    27. If a pattern contains capturing parentheses that are not used in a match,
755        their slots in the ovector are set to -1. For those that are higher than
756        any matched groups, this happens at the end of processing. In the case when
757        there were back references that the ovector was too small to contain
758        (causing temporary malloc'd memory to be used during matching), and the
759        highest capturing number was not used, memory off the end of the ovector
760        was incorrectly being set to -1. (It was using the size of the temporary
761        memory instead of the true size.)
763    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
764        ovector size, it uses memory at the end of the block that it has got.
766    29. Check for an overlong MARK name and give an error at compile time. The
767        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
769    30. JIT compiler update.
771    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
772        Rill for the patch.
774    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
776    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
778    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
779        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
780        was enabled.
782    35. Improve JIT code generation for greedy plus quantifier.
784    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
785        1 to "aa" instead of to an empty string. The bug affected repeated groups
786        that could potentially match an empty string.
788    37. Optimizing single character iterators in JIT.
790    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
791        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
792        codepoints that are too big for the mode are faulted, and in a UTF mode,
793        disallowed codepoints are also faulted.
795    39. If PCRE was compiled with UTF support, in three places in the DFA
796        matcher there was code that should only have been obeyed in UTF mode, but
797        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
798        processing when bytes with values greater than 127 were present. In 16-bit
799        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
800        both cases the values are those that cannot be the first data item in a UTF
801        character. The three items that might have provoked this were recursions,
802        possessively repeated groups, and atomic groups.
804    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
805        and pcregrep, because some OS require shared objects to be explicitly
806        passed to ld, causing the link step to fail if they are not.
808    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
809        mode, patterns that started with \h* or \R* might be incorrectly matched.
812    Version 8.30 04-February-2012
813    -----------------------------
815    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
816        name is defined in ctype.h.
818    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
819        only in quite long subpatterns.
821    3.  Removed the function pcre_info(), which has been obsolete and deprecated
822        since it was replaced by pcre_fullinfo() in February 2000.
824    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
825        match a (*MARK), and the match failed at the start of the subject, a
826        reference to memory before the start of the subject could occur. This bug
827        was introduced by fix 17 of release 8.21.
829    5.  A reference to an unset group with zero minimum repetition was giving
830        totally wrong answers (in non-JavaScript-compatibility mode). For example,
831        /(another)?(\1?)test/ matched against "hello world test". This bug was
832        introduced in release 8.13.
834    6.  Add support for 16-bit character strings (a large amount of work involving
835        many changes and refactorings).
837    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
838        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
839        from a file.
841    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
842        rounding is not applied in this particular case).
844    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
845        if they appear, or are escaped, in patterns.
847    10. Get rid of a number of -Wunused-but-set-variable warnings.
849    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
850        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
851        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
852        also returns the mark "x". This bug applied to capturing parentheses,
853        non-capturing parentheses, and atomic parentheses. It also applied to some
854        assertions.
856    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
857        information out of configure.ac instead of relying on pcre.h.generic, which
858        is not stored in the repository.
860    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
861        -lreadline.
863    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
865    15. Applied Graycode's patch to put the top-level frame on the stack rather
866        than the heap when not using the stack for recursion. This gives a
867        performance improvement in many cases when recursion is not deep.
869    16. Experimental code added to "pcretest -C" to output the stack frame size.
872    Version 8.21 12-Dec-2011
873    ------------------------
875    1.  Updating the JIT compiler.
877    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
878        are added as well.
880    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
881        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
882        calling _pcre_jit_exec. Some extra comments are added.
884    4.  (*MARK) settings inside atomic groups that do not contain any capturing
885        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
886        was introduced by change 18 for 8.20.
888    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
889        ECMA-262 standard.
891    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
892        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
893        This bug was probably introduced by change 9 of 8.13.
895    7.  While fixing 6 above, I noticed that a number of other items were being
896        incorrectly rejected as "not fixed length". This arose partly because newer
897        opcodes had not been added to the fixed-length checking code. I have (a)
898        corrected the bug and added tests for these items, and (b) arranged for an
899        error to occur if an unknown opcode is encountered while checking for fixed
900        length instead of just assuming "not fixed length". The items that were
901        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
902        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
903        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
905    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
906        being incorrectly compiled and would have given unpredicatble results.
908    9.  A possessively repeated subpattern with minimum repeat count greater than
909        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
910        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
911        the first (A) could occur when it should not.
913    10. Add a cast and remove a redundant test from the code.
915    11. JIT should use pcre_malloc/pcre_free for allocation.
917    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
918        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
919        is anything other than /usr, -L is still shown).
921    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
923    14. Perl does not support \N without a following name in a [] class; PCRE now
924        also gives an error.
926    15. If a forward reference was repeated with an upper limit of around 2000,
927        it caused the error "internal error: overran compiling workspace". The
928        maximum number of forward references (including repeats) was limited by the
929        internal workspace, and dependent on the LINK_SIZE. The code has been
930        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
931        the default depends on LINK_SIZE. There is a new upper limit (for safety)
932        of around 200,000 forward references. While doing this, I also speeded up
933        the filling in of repeated forward references.
935    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
936        incorrectly expecting the subject to contain another "a" after the start.
938    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
939        in the match, the SKIP should be ignored. This was not happening; instead
940        the SKIP was being treated as NOMATCH. For patterns such as
941        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
942        tested.
944    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
945        now much more compatible with Perl, in particular in cases where the result
946        is a non-match for a non-anchored pattern. For example, if
947        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
948        "m", where previously it did not return a name. A side effect of this
949        change is that for partial matches, the last encountered mark name is
950        returned, as for non matches. A number of tests that were previously not
951        Perl-compatible have been moved into the Perl-compatible test files. The
952        refactoring has had the pleasing side effect of removing one argument from
953        the match() function, thus reducing its stack requirements.
955    19. If the /S+ option was used in pcretest to study a pattern using JIT,
956        subsequent uses of /S (without +) incorrectly behaved like /S+.
958    21. Retrieve executable code size support for the JIT compiler and fixing
959        some warnings.
961    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
962        not work when the shorter character appeared right at the end of the
963        subject string.
965    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
966        systems.
968    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
969        output it when the /M option is used in pcretest.
971    25. The CheckMan script was not being included in the distribution. Also, added
972        an explicit "perl" to run Perl scripts from the PrepareRelease script
973        because this is reportedly needed in Windows.
975    26. If study data was being save in a file and studying had not found a set of
976        "starts with" bytes for the pattern, the data written to the file (though
977        never used) was taken from uninitialized memory and so caused valgrind to
978        complain.
980    27. Updated RunTest.bat as provided by Sheri Pierce.
982    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
984    29. Computation of memory usage for the table of capturing group names was
985        giving an unnecessarily large value.
988    Version 8.20 21-Oct-2011
989    ------------------------
991    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
992        a POSIX class. After further experiments with Perl, which convinced me that
993        Perl has bugs and confusions, a closing square bracket is no longer allowed
994        in a POSIX name. This bug also affected patterns with classes that started
995        with full stops.
997    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
998        captured substring, but while checking the failing first alternative,
999        substring 1 is temporarily captured. If the output vector supplied to
1000        pcre_exec() was not big enough for this capture, the yield of the function
1001        was still zero ("insufficient space for captured substrings"). This cannot
1002        be totally fixed without adding another stack variable, which seems a lot
1003        of expense for a edge case. However, I have improved the situation in cases
1004        such as /(a)(b)x|abc/ matched against "abc", where the return code
1005        indicates that fewer than the maximum number of slots in the ovector have
1006        been set.
1008    3.  Related to (2) above: when there are more back references in a pattern than
1009        slots in the output vector, pcre_exec() uses temporary memory during
1010        matching, and copies in the captures as far as possible afterwards. It was
1011        using the entire output vector, but this conflicts with the specification
1012        that only 2/3 is used for passing back captured substrings. Now it uses
1013        only the first 2/3, for compatibility. This is, of course, another edge
1014        case.
1016    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1017        main code base, and can be used by building with --enable-jit. When this is
1018        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1019        runtime --no-jit option is given.
1021    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1022        ovector, the return from the function was zero, implying that there were
1023        other matches that did not fit. The correct "exactly full" value is now
1024        returned.
1026    6.  If a subpattern that was called recursively or as a subroutine contained
1027        (*PRUNE) or any other control that caused it to give a non-standard return,
1028        invalid errors such as "Error -26 (nested recursion at the same subject
1029        position)" or even infinite loops could occur.
1031    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1032        computing the minimum length on reaching *ACCEPT, and so ended up with the
1033        wrong value of 1 rather than 0. Further investigation indicates that
1034        computing a minimum subject length in the presence of *ACCEPT is difficult
1035        (think back references, subroutine calls), and so I have changed the code
1036        so that no minimum is registered for a pattern that contains *ACCEPT.
1038    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1039        it was not handled as intended. [But see 16 below.]
1041    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1042        Sheri Pierce.
1044    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1045        the first byte in a match must be "a".
1047    11. Change 17 for 8.13 increased the recursion depth for patterns like
1048        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1049        pattern contains any instances of (*THEN). If it does not, the old
1050        optimizations are restored. It would be nice to do this on a per-group
1051        basis, but at the moment that is not feasible.
1053    12. In some environments, the output of pcretest -C is CRLF terminated. This
1054        broke RunTest's code that checks for the link size. A single white space
1055        character after the value is now allowed for.
1057    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1058        For "fr", it uses the Windows-specific input and output files.
1060    14. If (*THEN) appeared in a group that was called recursively or as a
1061        subroutine, it did not work as intended. [But see next item.]
1063    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1064        pattern fragments (but not containing any | characters). If A and B are
1065        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1066        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1067        D. In other words, Perl considers parentheses that do not contain any |
1068        characters to be part of a surrounding alternative, whereas PCRE was
1069        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1070        differently. PCRE now behaves in the same way as Perl, except in the case
1071        of subroutine/recursion calls such as (?1) which have in any case always
1072        been different (but PCRE had them first :-).
1074    16. Related to 15 above: Perl does not treat the | in a conditional group as
1075        creating alternatives. Such a group is treated in the same way as an
1076        ordinary group without any | characters when processing (*THEN). PCRE has
1077        been changed to match Perl's behaviour.
1079    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1080        RunGrepTest script failed.
1082    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1083        inevitable for groups that contain captures, but it can lead to a lot of
1084        stack use in large patterns. The old behaviour has been restored for atomic
1085        groups that do not contain any capturing parentheses.
1087    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1088        suppress the check for a minimum subject length at run time. (If it was
1089        given to pcre_exec() or pcre_dfa_exec() it did work.)
1091    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1092        fail to work when decoding hex characters in data strings in EBCDIC
1093        environments.
1095    21. It appears that in at least one Mac OS environment, the isxdigit() function
1096        is implemented as a macro that evaluates to its argument more than once,
1097        contravening the C 90 Standard (I haven't checked a later standard). There
1098        was an instance in pcretest which caused it to go wrong when processing
1099        \x{...} escapes in subject strings. The has been rewritten to avoid using
1100        things like p++ in the argument of isxdigit().
1103    Version 8.13 16-Aug-2011
1104    ------------------------
1106    1.  The Unicode data tables have been updated to Unicode 6.0.0.
1108    2.  Two minor typos in pcre_internal.h have been fixed.
1110    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
1111        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
1112        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
1114    4.  There were a number of related bugs in the code for matching backrefences
1115        caselessly in UTF-8 mode when codes for the characters concerned were
1116        different numbers of bytes. For example, U+023A and U+2C65 are an upper
1117        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
1118        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
1119        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1120        2-byte code at the end of the subject (it thought there wasn't enough data
1121        left).
1123    5.  Comprehensive information about what went wrong is now returned by
1124        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1125        as the output vector has at least 2 elements. The offset of the start of
1126        the failing character and a reason code are placed in the vector.
1128    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1129        now returned is for the first byte of the failing character, instead of the
1130        last byte inspected. This is an incompatible change, but I hope it is small
1131        enough not to be a problem. It makes the returned offset consistent with
1132        pcre_exec() and pcre_dfa_exec().
1134    7.  pcretest now gives a text phrase as well as the error number when
1135        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1136        failure, the offset and reason code are output.
1138    8.  When \R was used with a maximizing quantifier it failed to skip backwards
1139        over a \r\n pair if the subsequent match failed. Instead, it just skipped
1140        back over a single character (\n). This seems wrong (because it treated the
1141        two characters as a single entity when going forwards), conflicts with the
1142        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1143        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1144        has been changed.
1146    9.  Some internal refactoring has changed the processing so that the handling
1147        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1148        time (the PCRE_DOTALL option was changed this way some time ago: version
1149        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1150        which was always a bit of a fudge. It also means that there is one less
1151        argument for the match() function, which reduces its stack requirements
1152        slightly. This change also fixes an incompatibility with Perl: the pattern
1153        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1155    10. More internal refactoring has drastically reduced the number of recursive
1156        calls to match() for possessively repeated groups such as (abc)++ when
1157        using pcre_exec().
1159    11. While implementing 10, a number of bugs in the handling of groups were
1160        discovered and fixed:
1162        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1163        (a|)*(?1) gave a compile-time internal error.
1164        ((a|)+)+  did not notice that the outer group could match an empty string.
1165        (^a|^)+   was not marked as anchored.
1166        (.*a|.*)+ was not marked as matching at start or after a newline.
1168    12. Yet more internal refactoring has removed another argument from the match()
1169        function. Special calls to this function are now indicated by setting a
1170        value in a variable in the "match data" data block.
1172    13. Be more explicit in pcre_study() instead of relying on "default" for
1173        opcodes that mean there is no starting character; this means that when new
1174        ones are added and accidentally left out of pcre_study(), testing should
1175        pick them up.
1177    14. The -s option of pcretest has been documented for ages as being an old
1178        synonym of -m (show memory usage). I have changed it to mean "force study
1179        for every regex", that is, assume /S for every regex. This is similar to -i
1180        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1181        using it. It makes it easier to run collections of tests with and without
1182        study enabled, and thereby test pcre_study() more easily. All the standard
1183        tests are now run with and without -s (but some patterns can be marked as
1184        "never study" - see 20 below).
1186    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1187        restoration of the capturing data to the outer values was not happening
1188        correctly.
1190    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1191        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1192        pattern had matched an empty string, and so incorrectly returned a no
1193        match.
1195    17. There was optimizing code for the last branch of non-capturing parentheses,
1196        and also for the obeyed branch of a conditional subexpression, which used
1197        tail recursion to cut down on stack usage. Unfortunately, now that there is
1198        the possibility of (*THEN) occurring in these branches, tail recursion is
1199        no longer possible because the return has to be checked for (*THEN). These
1200        two optimizations have therefore been removed. [But see 8.20/11 above.]
1202    18. If a pattern containing \R was studied, it was assumed that \R always
1203        matched two bytes, thus causing the minimum subject length to be
1204        incorrectly computed because \R can also match just one byte.
1206    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1207        was incorrectly computed.
1209    20. If /S is present twice on a test pattern in pcretest input, it now
1210        *disables* studying, thereby overriding the use of -s on the command line
1211        (see 14 above). This is necessary for one or two tests to keep the output
1212        identical in both cases.
1214    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1215        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1217    22. When an atomic group that contained a capturing parenthesis was
1218        successfully matched, but the branch in which it appeared failed, the
1219        capturing was not being forgotten if a higher numbered group was later
1220        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1221        group 1 to "a", when in fact it should be unset. This applied to multi-
1222        branched capturing and non-capturing groups, repeated or not, and also to
1223        positive assertions (capturing in negative assertions does not happen
1224        in PCRE) and also to nested atomic groups.
1226    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1227        subject after a captured substring, to make it easier to tell which of a
1228        number of identical substrings has been captured.
1230    24. The way atomic groups are processed by pcre_exec() has been changed so that
1231        if they are repeated, backtracking one repetition now resets captured
1232        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1233        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1234        "aaa". Previously, it would have been "a". As part of this code
1235        refactoring, the way recursive calls are handled has also been changed.
1237    25. If an assertion condition captured any substrings, they were not passed
1238        back unless some other capturing happened later. For example, if
1239        (?(?=(a))a) was matched against "a", no capturing was returned.
1241    26. When studying a pattern that contained subroutine calls or assertions,
1242        the code for finding the minimum length of a possible match was handling
1243        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1244        group 1 called group 2 while simultaneously a separate group 2 called group
1245        1). A stack overflow occurred in this case. I have fixed this by limiting
1246        the recursion depth to 10.
1248    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1249        Fortmann. This supports explicit test numbers on the command line, and has
1250        argument validation and error reporting.
1252    28. An instance of \X with an unlimited repeat could fail if at any point the
1253        first character it looked at was a mark character.
1255    29. Some minor code refactoring concerning Unicode properties and scripts
1256        should reduce the stack requirement of match() slightly.
1258    30. Added the '=' option to pcretest to check the setting of unused capturing
1259        slots at the end of the pattern, which are documented as being -1, but are
1260        not included in the return count.
1262    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1263        compiled something random. Now it gives a compile-time error (as does
1264        Perl).
1266    32. A *MARK encountered during the processing of a positive assertion is now
1267        recorded and passed back (compatible with Perl).
1269    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1270        had alternative anchored branches, the search for a second match in a line
1271        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1272        matched the line "0102" twice. The same bug affected patterns that started
1273        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1274        twice.
1276    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1277        does, and because of capturing effects, quantifying parenthesized
1278        assertions may at times be useful. Quantifiers are now allowed for
1279        parenthesized assertions.
1281    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1283    36. \g was being checked for fancy things in a character class, when it should
1284        just be a literal "g".
1286    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1287        appearance of a nested POSIX class supersedes an apparent external class.
1288        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1289        unescaped square brackets may also appear as part of class names. For
1290        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1291        more like Perl. (But see 8.20/1 above.)
1293    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1294        was because it thought it was \N{name}, which is not supported).
1296    39. Add minix to OS list not supporting the -S option in pcretest.
1298    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1299        cannot analyze patterns in sufficient detail to catch mutual recursions
1300        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1301        subgroup is called recursively as a subpattern for a second time at the
1302        same position in the subject string. In previous releases this might have
1303        been caught by the recursion limit, or it might have run out of stack.
1305    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1306        happen only once. PCRE was, however incorrectly giving a compile time error
1307        "recursive call could loop indefinitely" because it cannot analyze the
1308        pattern in sufficient detail. The compile time test no longer happens when
1309        PCRE is compiling a conditional subpattern, but actual runaway loops are
1310        now caught at runtime (see 40 above).
1312    42. It seems that Perl allows any characters other than a closing parenthesis
1313        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1314        has been changed to be the same.
1316    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1317        as not to get warnings when autogen.sh is called. Also changed
1318        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1320    44. To help people who use pcregrep to scan files containing exceedingly long
1321        lines, the following changes have been made:
1323        (a) The default value of the buffer size parameter has been increased from
1324            8K to 20K. (The actual buffer used is three times this size.)
1326        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1327            PCRE is built.
1329        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1330            to be set at run time.
1332        (d) Numerical values in pcregrep options can be followed by K or M, for
1333            example --buffer-size=50K.
1335        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1336            given and the return code is set to 2.
1338    45. Add a pointer to the latest mark to the callout data block.
1340    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1341        partial match of an empty string instead of no match. This was specific to
1342        the use of ".".
1344    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1345        complete match instead of a partial match. This bug was dependent on both
1346        the PCRE_UTF8 and PCRE_DOTALL options being set.
1348    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1349        starting byte set, because \b was not being ignored.
1352    Version 8.12 15-Jan-2011
1353    ------------------------
1355    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1356        checks for such things as part of the documentation building process.
1358    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1359        --match-limit and --recursion-limit options (added for 8.11). In
1360        particular, this made one of the standard tests fail. (The integer value
1361        went into the wrong half of a long int.)
1363    3.  If the --colour option was given to pcregrep with -v (invert match), it
1364        did strange things, either producing crazy output, or crashing. It should,
1365        of course, ignore a request for colour when reporting lines that do not
1366        match.
1368    4.  Another pcregrep bug caused similar problems if --colour was specified with
1369        -M (multiline) and the pattern match finished with a line ending.
1371    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1372        matched in multiline mode, the following line was shown as part of the
1373        match. This seems wrong, so I have changed it.
1375    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1376        the check for further matches in the same line (so they could be coloured)
1377        to overrun the end of the current line. If another match was found, it was
1378        incorrectly shown (and then shown again when found in the next line).
1380    7.  If pcregrep was compiled under Windows, there was a reference to the
1381        function pcregrep_exit() before it was defined. I am assuming this was
1382        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1383        reported by a user. I've moved the definition above the reference.
1386    Version 8.11 10-Dec-2010
1387    ------------------------
1389    1.  (*THEN) was not working properly if there were untried alternatives prior
1390        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1391        backtracked to try for "b" instead of moving to the next alternative branch
1392        at the same level (in this case, to look for "c"). The Perl documentation
1393        is clear that when (*THEN) is backtracked onto, it goes to the "next
1394        alternative in the innermost enclosing group".
1396    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1397        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1398        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1399        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1400        (*THEN).
1402    3.  If \s appeared in a character class, it removed the VT character from
1403        the class, even if it had been included by some previous item, for example
1404        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1405        of \s, but is part of the POSIX "space" class.)
1407    4.  A partial match never returns an empty string (because you can always
1408        match an empty string at the end of the subject); however the checking for
1409        an empty string was starting at the "start of match" point. This has been
1410        changed to the "earliest inspected character" point, because the returned
1411        data for a partial match starts at this character. This means that, for
1412        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1413        (previously it gave "no match").
1415    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1416        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1417        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1418        has an implication that the given string is incomplete (because a partial
1419        match is preferred over a full match). For this reason, these items now
1420        give a partial match in this situation. [Aside: previously, the one case
1421        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1422        match rather than a full match, which was wrong by the old rules, but is
1423        now correct.]
1425    6.  There was a bug in the handling of #-introduced comments, recognized when
1426        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1427        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1428        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1429        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1430        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1431        places in pcre_compile().
1433    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1434        comments when looking ahead for named forward references to subpatterns,
1435        the only newline sequence it recognized was NL. It now handles newlines
1436        according to the set newline convention.
1438    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1439        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1440        cater for a lack of strerror(). These oversights have been fixed.
1442    9.  Added --match-limit and --recursion-limit to pcregrep.
1444    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1446    11. When the -o option was used, pcregrep was setting a return code of 1, even
1447        when matches were found, and --line-buffered was not being honoured.
1449    12. Added an optional parentheses number to the -o and --only-matching options
1450        of pcregrep.
1452    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1453        can match an empty string. The code to do it in pcretest and pcredemo
1454        needed fixing:
1456        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1457            only one byte after an empty string match just before CRLF (this case
1458            just got forgotten; "any" and "anycrlf" were OK).
1460        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1461            mode when an empty string match preceded an ASCII character followed by
1462            a non-ASCII character. (The code for advancing by one character rather
1463            than one byte was nonsense.)
1465        (c) The pcredemo.c sample program did not have any code at all to handle
1466            the cases when CRLF is a valid newline sequence.
1468    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1469        as a starting offset was within the subject string. There is now a new
1470        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1471        negative or greater than the length of the string. In order to test this,
1472        pcretest is extended to allow the setting of negative starting offsets.
1474    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1475        starting offset points to the beginning of a UTF-8 character was
1476        unnecessarily clumsy. I tidied it up.
1478    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1479        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1481    17. Nobody had reported that the --include_dir option, which was added in
1482        release 7.7 should have been called --include-dir (hyphen, not underscore)
1483        for compatibility with GNU grep. I have changed it to --include-dir, but
1484        left --include_dir as an undocumented synonym, and the same for
1485        --exclude-dir, though that is not available in GNU grep, at least as of
1486        release 2.5.4.
1488    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1489        characters from a string of bytes) have been redefined so as not to use
1490        loops, in order to improve performance in some environments. At the same
1491        time, I abstracted some of the common code into auxiliary macros to save
1492        repetition (this should not affect the compiled code).
1494    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1495        compile-time error is now given if \c is not followed by an ASCII
1496        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1497        different, and any byte value is allowed.)
1499    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1500        START_OPTIMIZE option, which is now allowed at compile time - but just
1501        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1502        to pcregrep and other applications that have no direct access to PCRE
1503        options. The new /Y option in pcretest sets this option when calling
1504        pcre_compile().
1506    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1507        back references. Groups containing recursive back references were forced to
1508        be atomic by that change, but in the case of named groups, the amount of
1509        memory required was incorrectly computed, leading to "Failed: internal
1510        error: code overflow". This has been fixed.
1512    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1513        pcretest.c, to avoid build problems in some Borland environments.
1516    Version 8.10 25-Jun-2010
1517  ------------------------  ------------------------
1519  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 42  Version 8.10 03-Jun-2010 Line 1554  Version 8.10 03-Jun-2010
1554  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1555      studied, and the match started with a letter with a code point greater than      studied, and the match started with a letter with a code point greater than
1556      127 whose first byte was different to the first byte of the other case of      127 whose first byte was different to the first byte of the other case of
1557      the letter, the other case of this starting letter was not recognized      the letter, the other case of this starting letter was not recognized
1558      (#976).      (#976).
1560  12. If a pattern that was studied started with a repeated Unicode property  12. If a pattern that was studied started with a repeated Unicode property
# Line 68  Version 8.10 03-Jun-2010 Line 1580  Version 8.10 03-Jun-2010
1581  17. Added a check for running out of memory when PCRE is compiled with  17. Added a check for running out of memory when PCRE is compiled with
1582      --disable-stack-for-recursion (#990).      --disable-stack-for-recursion (#990).
1584  18. If the last data line in a file for pcretest does not have a newline on  18. If the last data line in a file for pcretest does not have a newline on
1585      the end, a newline was missing in the output.      the end, a newline was missing in the output.
1587  19. The default pcre_chartables.c file recognizes only ASCII characters (values  19. The default pcre_chartables.c file recognizes only ASCII characters (values
1588      less than 128) in its various bitmaps. However, there is a facility for      less than 128) in its various bitmaps. However, there is a facility for
1589      generating tables according to the current locale when PCRE is compiled. It      generating tables according to the current locale when PCRE is compiled. It
1590      turns out that in some environments, 0x85 and 0xa0, which are Unicode space      turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1591      characters, are recognized by isspace() and therefore were getting set in      characters, are recognized by isspace() and therefore were getting set in
1592      these tables. This caused a problem in UTF-8 mode when pcre_study() was      these tables, and indeed these tables seem to approximate to ISO 8859. This
1593      used to create a list of bytes that can start a match. For \s, it was      caused a problem in UTF-8 mode when pcre_study() was used to create a list
1594      including 0x85 and 0xa0, which of course cannot start UTF-8 characters. I      of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1595      have changed the code so that only real ASCII characters (less than 128)      which of course cannot start UTF-8 characters. I have changed the code so
1596      are set in this case because the \s etc escapes are documented as      that only real ASCII characters (less than 128) and the correct starting
1597      recognizing only ASCII characters. (When PCRE_UCP is set - see 9 above -      bytes for UTF-8 encodings are set for characters greater than 127 when in
1598      the code is different altogether.)      UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1599        altogether.)
1601    20. Added the /T option to pcretest so as to be able to run tests with non-
1602        standard character tables, thus making it possible to include the tests
1603        used for 19 above in the standard set of tests.
1605    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1606        reference to a subpattern the other side of a comment that contains an
1607        opening parenthesis caused either an internal compiling error, or a
1608        reference to the wrong subpattern.
1611  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010
# Line 477  Version 7.9 11-Apr-09 Line 1999  Version 7.9 11-Apr-09
1999  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
2000      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
2001      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2002      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2003        8.33.]
2005  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
2006      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 720  Version 7.7 07-May-08 Line 2243  Version 7.7 07-May-08
2243      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2244      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2245      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2246      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2247      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2248      was subsequently set up correctly.)      was subsequently set up correctly.)

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