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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.13 30-Apr-2011  Version 8.37 xx-xxx-2015
5    ------------------------
7    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
8        for those parentheses to be closed with whatever has been captured so far.
9        However, it was failing to mark any other groups between the hightest
10        capture so far and the currrent group as "unset". Thus, the ovector for
11        those groups contained whatever was previously there. An example is the
12        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
14    2.  If an assertion condition was quantified with a minimum of zero (an odd
15        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
17    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
18        unrecognized modifier, a crash could occur.
20    4.  An attempt to do global matching in pcretest with a zero-length ovector
21        caused a crash.
23    5.  Fixed a memory leak during matching that could occur for a subpattern
24        subroutine call (recursive or otherwise) if the number of captured groups
25        that had to be saved was greater than ten.
27    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
28        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
29        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
32    Version 8.36 26-September-2014
33    ------------------------------
35    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
36        -Wmissing-field-initializers and -Wunused-parameter.
38    2.  The tests for quantifiers being too big (greater than 65535) were being
39        applied after reading the number, and stupidly assuming that integer
40        overflow would give a negative number. The tests are now applied as the
41        numbers are read.
43    3.  Tidy code in pcre_exec.c where two branches that used to be different are
44        now the same.
46    4.  The JIT compiler did not generate match limit checks for certain
47        bracketed expressions with quantifiers. This may lead to exponential
48        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
49        issue should be resolved now.
51    5.  Fixed an issue, which occures when nested alternatives are optimized
52        with table jumps.
54    6.  Inserted two casts and changed some ints to size_t in the light of some
55        reported 64-bit compiler warnings (Bugzilla 1477).
57    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
58        an empty string, which sometimes were behaving incorrectly in the
59        interpreter (though correctly in the JIT matcher). This pcretest input is
60        an example:
62          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
65        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
66        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
67        for an empty string was breaking the inner loop and carrying on at a lower
68        level, when possessive repeated groups should always return to a higher
69        level as they have no backtrack points in them. The empty string test now
70        occurs at the outer level.
72    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
73        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
75    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
76        doesn't).
78    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
79        to hold a pattern to be incorrectly computed (too small) when there were
80        named back references to duplicated names. This could cause "internal
81        error: code overflow" or "double free or corruption" or other memory
82        handling errors.
84    11. When named subpatterns had the same prefixes, back references could be
85        confused. For example, in this pattern:
87          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
89        the reference to 'Name' was incorrectly treated as a reference to a
90        duplicate name.
92    12. A pattern such as /^s?c/mi8 where the optional character has more than
93        one "other case" was incorrectly compiled such that it would only try to
94        match starting at "c".
96    13. When a pattern starting with \s was studied, VT was not included in the
97        list of possible starting characters; this should have been part of the
98        8.34/18 patch.
100    14. If a character class started [\Qx]... where x is any character, the class
101        was incorrectly terminated at the ].
103    15. If a pattern that started with a caseless match for a character with more
104        than one "other case" was studied, PCRE did not set up the starting code
105        unit bit map for the list of possible characters. Now it does. This is an
106        optimization improvement, not a bug fix.
108    16. The Unicode data tables have been updated to Unicode 7.0.0.
110    17. Fixed a number of memory leaks in pcregrep.
112    18. Avoid a compiler warning (from some compilers) for a function call with
113        a cast that removes "const" from an lvalue by using an intermediate
114        variable (to which the compiler does not object).
116    19. Incorrect code was compiled if a group that contained an internal recursive
117        back reference was optional (had quantifier with a minimum of zero). This
118        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
119        caused segmentation faults because of stack overflows at compile time.
121    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
122        group that is quantified with an indefinite repeat, caused a compile-time
123        loop which used up all the system stack and provoked a segmentation fault.
124        This was not the same bug as 19 above.
126    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
127        Patch by Mike Frysinger.
130    Version 8.35 04-April-2014
131    --------------------------
133    1.  A new flag is set, when property checks are present in an XCLASS.
134        When this flag is not set, PCRE can perform certain optimizations
135        such as studying these XCLASS-es.
137    2.  The auto-possessification of character sets were improved: a normal
138        and an extended character set can be compared now. Furthermore
139        the JIT compiler optimizes more character set checks.
141    3.  Got rid of some compiler warnings for potentially uninitialized variables
142        that show up only when compiled with -O2.
144    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
145        of a match later then the end of the match. The pcretest program was not
146        handling the case sensibly - it was outputting from the start to the next
147        binary zero. It now reports this situation in a message, and outputs the
148        text from the end to the start.
150    5.  Fast forward search is improved in JIT. Instead of the first three
151        characters, any three characters with fixed position can be searched.
152        Search order: first, last, middle.
154    6.  Improve character range checks in JIT. Characters are read by an inprecise
155        function now, which returns with an unknown value if the character code is
156        above a certain threshold (e.g: 256). The only limitation is that the value
157        must be bigger than the threshold as well. This function is useful when
158        the characters above the threshold are handled in the same way.
160    7.  The macros whose names start with RAWUCHAR are placeholders for a future
161        mode in which only the bottom 21 bits of 32-bit data items are used. To
162        make this more memorable for those maintaining the code, the names have
163        been changed to start with UCHAR21, and an extensive comment has been added
164        to their definition.
166    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
167        to the export list in Makefile.am (they were accidentally omitted from the
168        8.34 tarball).
170    9.  The informational output from pcretest used the phrase "starting byte set"
171        which is inappropriate for the 16-bit and 32-bit libraries. As the output
172        for "first char" and "need char" really means "non-UTF-char", I've changed
173        "byte" to "char", and slightly reworded the output. The documentation about
174        these values has also been (I hope) clarified.
176    10. Another JIT related optimization: use table jumps for selecting the correct
177        backtracking path, when more than four alternatives are present inside a
178        bracket.
180    11. Empty match is not possible, when the minimum length is greater than zero,
181        and there is no \K in the pattern. JIT should avoid empty match checks in
182        such cases.
184    12. In a caseless character class with UCP support, when a character with more
185        than one alternative case was not the first character of a range, not all
186        the alternative cases were added to the class. For example, s and \x{17f}
187        are both alternative cases for S: the class [RST] was handled correctly,
188        but [R-T] was not.
190    13. The configure.ac file always checked for pthread support when JIT was
191        enabled. This is not used in Windows, so I have put this test inside a
192        check for the presence of windows.h (which was already tested for).
194    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
195        The algorithm provides a way to skip certain starting offsets, and usually
196        faster than linear prefix searches.
198    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
199        as for 'fr_FR' and 'french'. For some reason, however, it then used the
200        Windows-specific input and output files, which have 'french' screwed in.
201        So this could never have worked. One of the problems with locales is that
202        they aren't always the same. I have now updated RunTest so that it checks
203        the output of the locale test (test 3) against three different output
204        files, and it allows the test to pass if any one of them matches. With luck
205        this should make the test pass on some versions of Solaris where it was
206        failing. Because of the uncertainty, the script did not used to stop if
207        test 3 failed; it now does. If further versions of a French locale ever
208        come to light, they can now easily be added.
210    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
211        there was a message during ./configure, but it did not stop. This now
212        provokes an error. The invalid example in README has been corrected.
213        If a value less than the minimum is given, the minimum value has always
214        been used, but now a warning is given.
216    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
217        was a bug in the test system, which is now fixed. Also, the list of various
218        configurations that are tested for each release did not have one with both
219        16/32 bits and --enable-bar-anycrlf. It now does.
221    18. pcretest was missing "-C bsr" for displaying the \R default setting.
223    19. Little endian PowerPC systems are supported now by the JIT compiler.
225    20. The fast forward newline mechanism could enter to an infinite loop on
226        certain invalid UTF-8 input. Although we don't support these cases
227        this issue can be fixed by a performance optimization.
229    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
230        not take account if existing stack usage. There is now a new global
231        variable called pcre_stack_guard that can be set to point to an external
232        function to check stack availability. It is called at the start of
233        processing every parenthesized group.
235    22. A typo in the code meant that in ungreedy mode the max/min qualifier
236        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
237        not match "ab".
239    23. When UTF was disabled, the JIT program reported some incorrect compile
240        errors. These messages are silenced now.
242    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
243        compiler.
245    25. Change all the temporary files used in RunGrepTest to be different to those
246        used by RunTest so that the tests can be run simultaneously, for example by
247        "make -j check".
250    Version 8.34 15-December-2013
251    -----------------------------
253    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
254        executable memory. Patch inspired by Carsten Klein.
256    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
257        this macro is never tested and has no effect, because the work to support
258        coverage involves only compiling and linking options and special targets in
259        the Makefile. The comment in config.h implied that defining the macro would
260        enable coverage support, which is totally false. There was also support for
261        setting this macro in the CMake files (my fault, I just copied it from
262        configure). SUPPORT_GCOV has now been removed.
264    3.  Make a small performance improvement in strlen16() and strlen32() in
265        pcretest.
267    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
268        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
269        these cases). There was also one in pcretest.c.
271    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
273    6.  In UTF mode, the code for checking whether a group could match an empty
274        string (which is used for indefinitely repeated groups to allow for
275        breaking an infinite loop) was broken when the group contained a repeated
276        negated single-character class with a character that occupied more than one
277        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
278        UTF-8 mode). The effect was undefined: the group might or might not be
279        deemed as matching an empty string, or the program might have crashed.
281    7.  The code for checking whether a group could match an empty string was not
282        recognizing that \h, \H, \v, \V, and \R must match a character.
284    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
285        an empty string. If it can, pcretest shows this in its information output.
287    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
288        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
289        matched by pcre_exec() without using JIT:
291        (a) If the rest of the pattern did not match after a maximal run of
292            grapheme clusters, the code for backing up to try with fewer of them
293            did not always back up over a full grapheme when characters that do not
294            have the modifier quality were involved, e.g. Hangul syllables.
296        (b) If the match point in a subject started with modifier character, and
297            there was no match, the code could incorrectly back up beyond the match
298            point, and potentially beyond the first character in the subject,
299            leading to a segfault or an incorrect match result.
301    10. A conditional group with an assertion condition could lead to PCRE
302        recording an incorrect first data item for a match if no other first data
303        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
304        first data item, and therefore matched "ca" after "c" instead of at the
305        start.
307    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
308        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
310    12. The source of pcregrep now includes z/OS-specific code so that it can be
311        compiled for z/OS as part of the special z/OS distribution.
313    13. Added the -T and -TM options to pcretest.
315    14. The code in pcre_compile.c for creating the table of named capturing groups
316        has been refactored. Instead of creating the table dynamically during the
317        actual compiling pass, the information is remembered during the pre-compile
318        pass (on the stack unless there are more than 20 named groups, in which
319        case malloc() is used) and the whole table is created before the actual
320        compile happens. This has simplified the code (it is now nearly 150 lines
321        shorter) and prepared the way for better handling of references to groups
322        with duplicate names.
324    15. A back reference to a named subpattern when there is more than one of the
325        same name now checks them in the order in which they appear in the pattern.
326        The first one that is set is used for the reference. Previously only the
327        first one was inspected. This change makes PCRE more compatible with Perl.
329    16. Unicode character properties were updated from Unicode 6.3.0.
331    17. The compile-time code for auto-possessification has been refactored, based
332        on a patch by Zoltan Herczeg. It now happens after instead of during
333        compilation. The code is cleaner, and more cases are handled. The option
334        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
335        options in pcretest are provided to set it. It can also be set by
336        (*NO_AUTO_POSSESS) at the start of a pattern.
338    18. The character VT has been added to the default ("C" locale) set of
339        characters that match \s and are generally treated as white space,
340        following this same change in Perl 5.18. There is now no difference between
341        "Perl space" and "POSIX space". Whether VT is treated as white space in
342        other locales depends on the locale.
344    19. The code for checking named groups as conditions, either for being set or
345        for being recursed, has been refactored (this is related to 14 and 15
346        above). Processing unduplicated named groups should now be as fast at
347        numerical groups, and processing duplicated groups should be faster than
348        before.
350    20. Two patches to the CMake build system, by Alexander Barkov:
352          (1) Replace the "source" command by "." in CMakeLists.txt because
353              "source" is a bash-ism.
355          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
356              without these the CMake build does not work on Solaris.
358    21. Perl has changed its handling of \8 and \9. If there is no previously
359        encountered capturing group of those numbers, they are treated as the
360        literal characters 8 and 9 instead of a binary zero followed by the
361        literals. PCRE now does the same.
363    22. Following Perl, added \o{} to specify codepoints in octal, making it
364        possible to specify values greater than 0777 and also making them
365        unambiguous.
367    23. Perl now gives an error for missing closing braces after \x{... instead of
368        treating the string as literal. PCRE now does the same.
370    24. RunTest used to grumble if an inappropriate test was selected explicitly,
371        but just skip it when running all tests. This make it awkward to run ranges
372        of tests when one of them was inappropriate. Now it just skips any
373        inappropriate tests, as it always did when running all tests.
375    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
376        character types such as \d or \w, too many callouts were inserted, and the
377        data that they returned was rubbish.
379    26. In UCP mode, \s was not matching two of the characters that Perl matches,
380        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
381        were matched by \h. The code has now been refactored so that the lists of
382        the horizontal and vertical whitespace characters used for \h and \v (which
383        are defined only in one place) are now also used for \s.
385    27. Add JIT support for the 64 bit TileGX architecture.
386        Patch by Jiong Wang (Tilera Corporation).
388    28. Possessive quantifiers for classes (both explicit and automatically
389        generated) now use special opcodes instead of wrapping in ONCE brackets.
391    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
392        (because it's meaningless), this was not happening when PCRE_CASELESS was
393        set. Not wrong, but inefficient.
395    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
396        properties for \w, \d, etc) is present in a test regex. Otherwise if the
397        test contains no characters greater than 255, Perl doesn't realise it
398        should be using Unicode semantics.
400    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
401        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
402        does in Unicode mode.
404    32. Added the "forbid" facility to pcretest so that putting tests into the
405        wrong test files can sometimes be quickly detected.
407    33. There is now a limit (default 250) on the depth of nesting of parentheses.
408        This limit is imposed to control the amount of system stack used at compile
409        time. It can be changed at build time by --with-parens-nest-limit=xxx or
410        the equivalent in CMake.
412    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
413        errors. Perl warns for these when in warning mode, but PCRE has no facility
414        for giving warnings.
416    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
417        However, this was not working for (?!) because it is optimized to (*FAIL),
418        for which PCRE does not allow quantifiers. The optimization is now disabled
419        when a quantifier follows (?!). I can't see any use for this, but it makes
420        things uniform.
422    36. Perl no longer allows group names to start with digits, so I have made this
423        change also in PCRE. It simplifies the code a bit.
425    37. In extended mode, Perl ignores spaces before a + that indicates a
426        possessive quantifier. PCRE allowed a space before the quantifier, but not
427        before the possessive +. It now does.
429    38. The use of \K (reset reported match start) within a repeated possessive
430        group such as (a\Kb)*+ was not working.
432    40. Document that the same character tables must be used at compile time and
433        run time, and that the facility to pass tables to pcre_exec() and
434        pcre_dfa_exec() is for use only with saved/restored patterns.
436    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
437        features for Builds with MSVC:
439        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
440           builds). The .rc files can be used to set FileDescription and many other
441           attributes.
443        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
444           This allows higher-level build scripts which want .pdb files to avoid
445           hard-coding the exact files needed."
447    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
448        mean "start of word" and "end of word", respectively, as a transition aid.
450    43. A minimizing repeat of a class containing codepoints greater than 255 in
451        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
452        compiled to use the heap for recursion.
454    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
455        is configured.
458    Version 8.33 28-May-2013
459    ------------------------
461    1.  Added 'U' to some constants that are compared to unsigned integers, to
462        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
463        variables that are added to signed variables, to ensure the result is
464        signed and can be negated.
466    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
467        CMake config files.
469    3.  Revise the creation of config.h.generic so that all boolean macros are
470        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
471        overriding via -D on the command line possible.
473    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
474        to unsigned int is reported to make a quite noticeable speed difference in
475        a specific Windows environment. Testing on Linux did also appear to show
476        some benefit (and it is clearly not harmful). Also fixed the definition of
477        Xop which should be unsigned.
479    5.  Related to (4), changing the definition of the intermediate variable cc
480        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
481        improvements.
483    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
484        unnecessary spaces.
486    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
487        and later.
489    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
491    9.  Optimizing fast_forward_start_bits in JIT.
493    10. Adding support for callouts in JIT, and fixing some issues revealed
494        during this work. Namely:
496        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
498        (b) Minimum length was not checked before the matching is started.
500    11. The value of capture_last that is passed to callouts was incorrect in some
501        cases when there was a capture on one path that was subsequently abandoned
502        after a backtrack. Also, the capture_last value is now reset after a
503        recursion, since all captures are also reset in this case.
505    12. The interpreter no longer returns the "too many substrings" error in the
506        case when an overflowing capture is in a branch that is subsequently
507        abandoned after a backtrack.
509    13. In the pathological case when an offset vector of size 2 is used, pcretest
510        now prints out the matched string after a yield of 0 or 1.
512    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
513        Only supported by the JIT compiler at the moment.
515    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
517    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
518        offset of the starting point of the matching process, provided the offsets
519        vector is large enough.
521    17. The \A escape now records a lookbehind value of 1, though its execution
522        does not actually inspect the previous character. This is to ensure that,
523        in partial multi-segment matching, at least one character from the old
524        segment is retained when a new segment is processed. Otherwise, if there
525        are no lookbehinds in the pattern, \A might match incorrectly at the start
526        of a new segment.
528    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
530    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
531        gives some modest performance improvement in 8-bit mode.
533    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
534        be expressed in certain programming languages using Universal Character
535        Names.
537    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
538        which points out that "non characters" are not "characters that may not
539        appear in Unicode strings" but rather "characters that are reserved for
540        internal use and have only local meaning".
542    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
543        there was a conditional group that depended on an assertion, if the
544        assertion was false, the callout that immediately followed the alternation
545        in the condition was skipped when pcre_exec() was used for matching.
547    23. Allow an explicit callout to be inserted before an assertion that is the
548        condition for a conditional group, for compatibility with automatic
549        callouts, which always insert a callout at this point.
551    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
552        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
554    25. (*PRUNE) is now supported by the JIT compiler.
556    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
558    27. Fix the case where there are two or more SKIPs with arguments that may be
559        ignored.
561    28. (*SKIP) is now supported by the JIT compiler.
563    29. (*THEN) is now supported by the JIT compiler.
565    30. Update RunTest with additional test selector options.
567    31. The way PCRE handles backtracking verbs has been changed in two ways.
569        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
570        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
571        backtracking. In some cases this makes it more Perl-compatible, but Perl's
572        rather obscure rules do not always do the same thing.
574        (2) Previously, backtracking verbs were confined within assertions. This is
575        no longer the case for positive assertions, except for (*ACCEPT). Again,
576        this sometimes improves Perl compatibility, and sometimes does not.
578    32. A number of tests that were in test 2 because Perl did things differently
579        have been moved to test 1, because either Perl or PCRE has changed, and
580        these tests are now compatible.
582    32. Backtracking control verbs are now handled in the same way in JIT and
583        interpreter.
585    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
586        contained a forward subroutine reference caused a compile error.
588    34. Auto-detect and optimize limited repetitions in JIT.
590    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
591        blocking (*UTF) etc.
593    36. In the interpreter, maximizing pattern repetitions for characters and
594        character types now use tail recursion, which reduces stack usage.
596    37. The value of the max lookbehind was not correctly preserved if a compiled
597        and saved regex was reloaded on a host of different endianness.
599    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
600        of the compiled pattern block, expand the flags field from 16 to 32 bits
601        because it was almost full.
603    39. Try madvise first before posix_madvise.
605    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
606        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
607        original change locked out all matches of empty strings. This has been
608        changed so that one match of an empty string per line is recognized.
609        Subsequent searches on the same line (for colouring or for --only-matching,
610        for example) do not recognize empty strings.
612    41. Applied a user patch to fix a number of spelling mistakes in comments.
614    42. Data lines longer than 65536 caused pcretest to crash.
616    43. Clarified the data type for length and startoffset arguments for pcre_exec
617        and pcre_dfa_exec in the function-specific man pages, where they were
618        explicitly stated to be in bytes, never having been updated. I also added
619        some clarification to the pcreapi man page.
621    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
622        a segmentation fault.
625    Version 8.32 30-November-2012
626    -----------------------------
628    1.  Improved JIT compiler optimizations for first character search and single
629        character iterators.
631    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
632        Patch by Daniel Richard G.
634    3.  Single character iterator optimizations in the JIT compiler.
636    4.  Improved JIT compiler optimizations for character ranges.
638    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
639        Reported by Giuseppe D'Angelo.
641    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
642        of a line, was being set incorrectly in cases where .* appeared inside
643        atomic brackets at the start of a pattern, or where there was a subsequent
644        *PRUNE or *SKIP.
646    7.  Improved instruction cache flush for POWER/PowerPC.
647        Patch by Daniel Richard G.
649    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
650        grep:
652        (a) There is now no limit to the number of patterns to be matched.
654        (b) An error is given if a pattern is too long.
656        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
657            are now supported.
659        (d) --exclude-from and --include-from (multiple use) have been added.
661        (e) Exclusions and inclusions now apply to all files and directories, not
662            just to those obtained from scanning a directory recursively.
664        (f) Multiple uses of -f and --file-list are now supported.
666        (g) In a Windows environment, the default for -d has been changed from
667            "read" (the GNU grep default) to "skip", because otherwise the presence
668            of a directory in the file list provokes an error.
670        (h) The documentation has been revised and clarified in places.
672    9.  Improve the matching speed of capturing brackets.
674    10. Changed the meaning of \X so that it now matches a Unicode extended
675        grapheme cluster.
677    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
678        out POSIX threads when JIT support is configured.
680    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
682    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
683        structure could go wrong in environments where size_t is not the same size
684        as int.
686    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
687        set.
689    15. The EBCDIC support had decayed; later updates to the code had included
690        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
691        general tidy up of EBCDIC-related issues, and the documentation was also
692        not quite right. There is now a test that can be run on ASCII systems to
693        check some of the EBCDIC-related things (but is it not a full test).
695    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
696        in a small tidy to the code.
698    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
700    18. If the --only-matching (-o) option in pcregrep is specified multiple
701        times, each one causes appropriate output. For example, -o1 -o2 outputs the
702        substrings matched by the 1st and 2nd capturing parentheses. A separating
703        string can be specified by --om-separator (default empty).
705    19. Improving the first n character searches.
707    20. Turn case lists for horizontal and vertical white space into macros so that
708        they are defined only once.
710    21. This set of changes together give more compatible Unicode case-folding
711        behaviour for characters that have more than one other case when UCP
712        support is available.
714        (a) The Unicode property table now has offsets into a new table of sets of
715            three or more characters that are case-equivalent. The MultiStage2.py
716            script that generates these tables (the pcre_ucd.c file) now scans
717            CaseFolding.txt instead of UnicodeData.txt for character case
718            information.
720        (b) The code for adding characters or ranges of characters to a character
721            class has been abstracted into a generalized function that also handles
722            case-independence. In UTF-mode with UCP support, this uses the new data
723            to handle characters with more than one other case.
725        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
726            whose other case is greater than 256 are now correctly matched
727            caselessly. Previously, the high codepoint matched the low one, but not
728            vice versa.
730        (d) The processing of \h, \H, \v, and \ in character classes now makes use
731            of the new class addition function, using character lists defined as
732            macros alongside the case definitions of 20 above.
734        (e) Caseless back references now work with characters that have more than
735            one other case.
737        (f) General caseless matching of characters with more than one other case
738            is supported.
740    22. Unicode character properties were updated from Unicode 6.2.0
742    23. Improved CMake support under Windows. Patch by Daniel Richard G.
744    24. Add support for 32-bit character strings, and UTF-32
746    25. Major JIT compiler update (code refactoring and bugfixing).
747        Experimental Sparc 32 support is added.
749    26. Applied a modified version of Daniel Richard G's patch to create
750        pcre.h.generic and config.h.generic by "make" instead of in the
751        PrepareRelease script.
753    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
754        pcre_compile.c when checking for a zero character.
756    28. Introducing a native interface for JIT. Through this interface, the compiled
757        machine code can be directly executed. The purpose of this interface is to
758        provide fast pattern matching, so several sanity checks are not performed.
759        However, feature tests are still performed. The new interface provides
760        1.4x speedup compared to the old one.
762    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
763        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
764        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
766    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
767        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
768        the "old" RFC 2279). Instead, it ended up passing a negative length to
769        pcre_exec().
771    31. Add support for GCC's visibility feature to hide internal functions.
773    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
774        "unknown -C option" after outputting 0 or 1.
776    33. There is now support for generating a code coverage report for the test
777        suite in environments where gcc is the compiler and lcov is installed. This
778        is mainly for the benefit of the developers.
780    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
781        unaddressable using valgrind annotations, allowing valgrind to detect
782        invalid memory accesses. This is mainly for the benefit of the developers.
784    25. (*UTF) can now be used to start a pattern in any of the three libraries.
786    26. Give configure error if --enable-cpp but no C++ compiler found.
789    Version 8.31 06-July-2012
790    -------------------------
792    1.  Fixing a wrong JIT test case and some compiler warnings.
794    2.  Removed a bashism from the RunTest script.
796    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
797        to unsigned type, result still unsigned" that was given by an MS compiler
798        on encountering the code "-sizeof(xxx)".
800    4.  Partial matching support is added to the JIT compiler.
802    5.  Fixed several bugs concerned with partial matching of items that consist
803        of more than one character:
805        (a) /^(..)\1/ did not partially match "aba" because checking references was
806            done on an "all or nothing" basis. This also applied to repeated
807            references.
809        (b) \R did not give a hard partial match if \r was found at the end of the
810            subject.
812        (c) \X did not give a hard partial match after matching one or more
813            characters at the end of the subject.
815        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
816            a partial match for the string "\r".
818        (e) When newline was set to CRLF, the metacharacter "." did not recognize
819            a partial match for a CR character at the end of the subject string.
821    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
822        running pcretest, the text "(JIT)" added to the output whenever JIT is
823        actually used to run the match.
825    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
826        or /S+[+] with a digit between 1 and 7.
828    8.  OP_NOT now supports any UTF character not just single-byte ones.
830    9.  (*MARK) control verb is now supported by the JIT compiler.
832    10. The command "./RunTest list" lists the available tests without actually
833        running any of them. (Because I keep forgetting what they all are.)
837    12. Applied a (slightly modified) user-supplied patch that improves performance
838        when the heap is used for recursion (compiled with --disable-stack-for-
839        recursion). Instead of malloc and free for each heap frame each time a
840        logical recursion happens, frames are retained on a chain and re-used where
841        possible. This sometimes gives as much as 30% improvement.
843    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
844        call.
846    14. As documented, (*COMMIT) is now confined to within a positive assertion.
848    15. It is now possible to link pcretest with libedit as an alternative to
849        libreadline.
851    16. (*COMMIT) control verb is now supported by the JIT compiler.
853    17. The Unicode data tables have been updated to Unicode 6.1.0.
855    18. Added --file-list option to pcregrep.
857    19. Added binary file support to pcregrep, including the -a, --binary-files,
858        -I, and --text options.
860    20. The madvise function is renamed for posix_madvise for QNX compatibility
861        reasons. Fixed by Giuseppe D'Angelo.
863    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
865    22. Changed the option for creating symbolic links for 16-bit man pages from
866        -s to -sf so that re-installing does not cause issues.
868    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
870    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
871        matches in certain environments (the workspace was not being correctly
872        retained). Also added to pcre_dfa_exec() a simple plausibility check on
873        some of the workspace data at the beginning of a restart.
875    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
876        was not doing so when it should - probably a typo introduced by SVN 528
877        (change 8.10/14).
879    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
880        \w+ when the character tables indicated that \x{c4} was a word character.
881        There were several related cases, all because the tests for doing a table
882        lookup were testing for characters less than 127 instead of 255.
884    27. If a pattern contains capturing parentheses that are not used in a match,
885        their slots in the ovector are set to -1. For those that are higher than
886        any matched groups, this happens at the end of processing. In the case when
887        there were back references that the ovector was too small to contain
888        (causing temporary malloc'd memory to be used during matching), and the
889        highest capturing number was not used, memory off the end of the ovector
890        was incorrectly being set to -1. (It was using the size of the temporary
891        memory instead of the true size.)
893    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
894        ovector size, it uses memory at the end of the block that it has got.
896    29. Check for an overlong MARK name and give an error at compile time. The
897        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
899    30. JIT compiler update.
901    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
902        Rill for the patch.
904    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
906    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
908    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
909        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
910        was enabled.
912    35. Improve JIT code generation for greedy plus quantifier.
914    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
915        1 to "aa" instead of to an empty string. The bug affected repeated groups
916        that could potentially match an empty string.
918    37. Optimizing single character iterators in JIT.
920    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
921        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
922        codepoints that are too big for the mode are faulted, and in a UTF mode,
923        disallowed codepoints are also faulted.
925    39. If PCRE was compiled with UTF support, in three places in the DFA
926        matcher there was code that should only have been obeyed in UTF mode, but
927        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
928        processing when bytes with values greater than 127 were present. In 16-bit
929        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
930        both cases the values are those that cannot be the first data item in a UTF
931        character. The three items that might have provoked this were recursions,
932        possessively repeated groups, and atomic groups.
934    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
935        and pcregrep, because some OS require shared objects to be explicitly
936        passed to ld, causing the link step to fail if they are not.
938    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
939        mode, patterns that started with \h* or \R* might be incorrectly matched.
942    Version 8.30 04-February-2012
943    -----------------------------
945    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
946        name is defined in ctype.h.
948    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
949        only in quite long subpatterns.
951    3.  Removed the function pcre_info(), which has been obsolete and deprecated
952        since it was replaced by pcre_fullinfo() in February 2000.
954    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
955        match a (*MARK), and the match failed at the start of the subject, a
956        reference to memory before the start of the subject could occur. This bug
957        was introduced by fix 17 of release 8.21.
959    5.  A reference to an unset group with zero minimum repetition was giving
960        totally wrong answers (in non-JavaScript-compatibility mode). For example,
961        /(another)?(\1?)test/ matched against "hello world test". This bug was
962        introduced in release 8.13.
964    6.  Add support for 16-bit character strings (a large amount of work involving
965        many changes and refactorings).
967    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
968        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
969        from a file.
971    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
972        rounding is not applied in this particular case).
974    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
975        if they appear, or are escaped, in patterns.
977    10. Get rid of a number of -Wunused-but-set-variable warnings.
979    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
980        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
981        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
982        also returns the mark "x". This bug applied to capturing parentheses,
983        non-capturing parentheses, and atomic parentheses. It also applied to some
984        assertions.
986    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
987        information out of configure.ac instead of relying on pcre.h.generic, which
988        is not stored in the repository.
990    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
991        -lreadline.
993    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
995    15. Applied Graycode's patch to put the top-level frame on the stack rather
996        than the heap when not using the stack for recursion. This gives a
997        performance improvement in many cases when recursion is not deep.
999    16. Experimental code added to "pcretest -C" to output the stack frame size.
1002    Version 8.21 12-Dec-2011
1003    ------------------------
1005    1.  Updating the JIT compiler.
1007    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1008        are added as well.
1010    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1011        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1012        calling _pcre_jit_exec. Some extra comments are added.
1014    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1015        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1016        was introduced by change 18 for 8.20.
1018    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1019        ECMA-262 standard.
1021    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1022        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1023        This bug was probably introduced by change 9 of 8.13.
1025    7.  While fixing 6 above, I noticed that a number of other items were being
1026        incorrectly rejected as "not fixed length". This arose partly because newer
1027        opcodes had not been added to the fixed-length checking code. I have (a)
1028        corrected the bug and added tests for these items, and (b) arranged for an
1029        error to occur if an unknown opcode is encountered while checking for fixed
1030        length instead of just assuming "not fixed length". The items that were
1031        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1032        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1033        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1035    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1036        being incorrectly compiled and would have given unpredicatble results.
1038    9.  A possessively repeated subpattern with minimum repeat count greater than
1039        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1040        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1041        the first (A) could occur when it should not.
1043    10. Add a cast and remove a redundant test from the code.
1045    11. JIT should use pcre_malloc/pcre_free for allocation.
1047    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1048        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1049        is anything other than /usr, -L is still shown).
1051    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1053    14. Perl does not support \N without a following name in a [] class; PCRE now
1054        also gives an error.
1056    15. If a forward reference was repeated with an upper limit of around 2000,
1057        it caused the error "internal error: overran compiling workspace". The
1058        maximum number of forward references (including repeats) was limited by the
1059        internal workspace, and dependent on the LINK_SIZE. The code has been
1060        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1061        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1062        of around 200,000 forward references. While doing this, I also speeded up
1063        the filling in of repeated forward references.
1065    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1066        incorrectly expecting the subject to contain another "a" after the start.
1068    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1069        in the match, the SKIP should be ignored. This was not happening; instead
1070        the SKIP was being treated as NOMATCH. For patterns such as
1071        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1072        tested.
1074    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1075        now much more compatible with Perl, in particular in cases where the result
1076        is a non-match for a non-anchored pattern. For example, if
1077        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1078        "m", where previously it did not return a name. A side effect of this
1079        change is that for partial matches, the last encountered mark name is
1080        returned, as for non matches. A number of tests that were previously not
1081        Perl-compatible have been moved into the Perl-compatible test files. The
1082        refactoring has had the pleasing side effect of removing one argument from
1083        the match() function, thus reducing its stack requirements.
1085    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1086        subsequent uses of /S (without +) incorrectly behaved like /S+.
1088    21. Retrieve executable code size support for the JIT compiler and fixing
1089        some warnings.
1091    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1092        not work when the shorter character appeared right at the end of the
1093        subject string.
1095    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1096        systems.
1098    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1099        output it when the /M option is used in pcretest.
1101    25. The CheckMan script was not being included in the distribution. Also, added
1102        an explicit "perl" to run Perl scripts from the PrepareRelease script
1103        because this is reportedly needed in Windows.
1105    26. If study data was being save in a file and studying had not found a set of
1106        "starts with" bytes for the pattern, the data written to the file (though
1107        never used) was taken from uninitialized memory and so caused valgrind to
1108        complain.
1110    27. Updated RunTest.bat as provided by Sheri Pierce.
1112    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1114    29. Computation of memory usage for the table of capturing group names was
1115        giving an unnecessarily large value.
1118    Version 8.20 21-Oct-2011
1119    ------------------------
1121    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1122        a POSIX class. After further experiments with Perl, which convinced me that
1123        Perl has bugs and confusions, a closing square bracket is no longer allowed
1124        in a POSIX name. This bug also affected patterns with classes that started
1125        with full stops.
1127    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1128        captured substring, but while checking the failing first alternative,
1129        substring 1 is temporarily captured. If the output vector supplied to
1130        pcre_exec() was not big enough for this capture, the yield of the function
1131        was still zero ("insufficient space for captured substrings"). This cannot
1132        be totally fixed without adding another stack variable, which seems a lot
1133        of expense for a edge case. However, I have improved the situation in cases
1134        such as /(a)(b)x|abc/ matched against "abc", where the return code
1135        indicates that fewer than the maximum number of slots in the ovector have
1136        been set.
1138    3.  Related to (2) above: when there are more back references in a pattern than
1139        slots in the output vector, pcre_exec() uses temporary memory during
1140        matching, and copies in the captures as far as possible afterwards. It was
1141        using the entire output vector, but this conflicts with the specification
1142        that only 2/3 is used for passing back captured substrings. Now it uses
1143        only the first 2/3, for compatibility. This is, of course, another edge
1144        case.
1146    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1147        main code base, and can be used by building with --enable-jit. When this is
1148        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1149        runtime --no-jit option is given.
1151    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1152        ovector, the return from the function was zero, implying that there were
1153        other matches that did not fit. The correct "exactly full" value is now
1154        returned.
1156    6.  If a subpattern that was called recursively or as a subroutine contained
1157        (*PRUNE) or any other control that caused it to give a non-standard return,
1158        invalid errors such as "Error -26 (nested recursion at the same subject
1159        position)" or even infinite loops could occur.
1161    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1162        computing the minimum length on reaching *ACCEPT, and so ended up with the
1163        wrong value of 1 rather than 0. Further investigation indicates that
1164        computing a minimum subject length in the presence of *ACCEPT is difficult
1165        (think back references, subroutine calls), and so I have changed the code
1166        so that no minimum is registered for a pattern that contains *ACCEPT.
1168    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1169        it was not handled as intended. [But see 16 below.]
1171    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1172        Sheri Pierce.
1174    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1175        the first byte in a match must be "a".
1177    11. Change 17 for 8.13 increased the recursion depth for patterns like
1178        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1179        pattern contains any instances of (*THEN). If it does not, the old
1180        optimizations are restored. It would be nice to do this on a per-group
1181        basis, but at the moment that is not feasible.
1183    12. In some environments, the output of pcretest -C is CRLF terminated. This
1184        broke RunTest's code that checks for the link size. A single white space
1185        character after the value is now allowed for.
1187    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1188        For "fr", it uses the Windows-specific input and output files.
1190    14. If (*THEN) appeared in a group that was called recursively or as a
1191        subroutine, it did not work as intended. [But see next item.]
1193    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1194        pattern fragments (but not containing any | characters). If A and B are
1195        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1196        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1197        D. In other words, Perl considers parentheses that do not contain any |
1198        characters to be part of a surrounding alternative, whereas PCRE was
1199        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1200        differently. PCRE now behaves in the same way as Perl, except in the case
1201        of subroutine/recursion calls such as (?1) which have in any case always
1202        been different (but PCRE had them first :-).
1204    16. Related to 15 above: Perl does not treat the | in a conditional group as
1205        creating alternatives. Such a group is treated in the same way as an
1206        ordinary group without any | characters when processing (*THEN). PCRE has
1207        been changed to match Perl's behaviour.
1209    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1210        RunGrepTest script failed.
1212    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1213        inevitable for groups that contain captures, but it can lead to a lot of
1214        stack use in large patterns. The old behaviour has been restored for atomic
1215        groups that do not contain any capturing parentheses.
1217    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1218        suppress the check for a minimum subject length at run time. (If it was
1219        given to pcre_exec() or pcre_dfa_exec() it did work.)
1221    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1222        fail to work when decoding hex characters in data strings in EBCDIC
1223        environments.
1225    21. It appears that in at least one Mac OS environment, the isxdigit() function
1226        is implemented as a macro that evaluates to its argument more than once,
1227        contravening the C 90 Standard (I haven't checked a later standard). There
1228        was an instance in pcretest which caused it to go wrong when processing
1229        \x{...} escapes in subject strings. The has been rewritten to avoid using
1230        things like p++ in the argument of isxdigit().
1233    Version 8.13 16-Aug-2011
1234  ------------------------  ------------------------
1236  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 20  Version 8.13 30-Apr-2011 Line 1249  Version 8.13 30-Apr-2011
1249      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1250      2-byte code at the end of the subject (it thought there wasn't enough data      2-byte code at the end of the subject (it thought there wasn't enough data
1251      left).      left).
1253  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
1254      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1255      as the output vector has at least 2 elements. The offset of the start of      as the output vector has at least 2 elements. The offset of the start of
1256      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
1258  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1259      now returned is for the first byte of the failing character, instead of the      now returned is for the first byte of the failing character, instead of the
1260      last byte inspected. This is an incompatible change, but I hope it is small      last byte inspected. This is an incompatible change, but I hope it is small
1261      enough not to be a problem. It makes the returned offset consistent with      enough not to be a problem. It makes the returned offset consistent with
1262      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
1264  7.  pcretest now gives a text phrase as well as the error number when  7.  pcretest now gives a text phrase as well as the error number when
1265      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1266      failure, the offset and reason code are output.      failure, the offset and reason code are output.
1268  8.  When \R was used with a maximizing quantifier it failed to skip backwards  8.  When \R was used with a maximizing quantifier it failed to skip backwards
1269      over a \r\n pair if the subsequent match failed. Instead, it just skipped      over a \r\n pair if the subsequent match failed. Instead, it just skipped
1270      back over a single character (\n). This seems wrong (because it treated the      back over a single character (\n). This seems wrong (because it treated the
1271      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
1272      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1273      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1274      has been changed.      has been changed.
1276  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
1277      of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile      of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1278      time (the PCRE_DOTALL option was changed this way some time ago: version      time (the PCRE_DOTALL option was changed this way some time ago: version
1279      7.7 change 16). This has made it possible to abolish the OP_OPT op code,      7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1280      which was always a bit of a fudge. It also means that there is one less      which was always a bit of a fudge. It also means that there is one less
1281      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
1282      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
1283      (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.      (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1285  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
1286      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
1287      using pcre_exec().      using pcre_exec().
1289  11. While implementing 10, a number of bugs in the handling of groups were  11. While implementing 10, a number of bugs in the handling of groups were
1290      discovered and fixed:      discovered and fixed:
1292      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1293      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
1294      ((a|)+)+  did not notice that the outer group could match an empty string.      ((a|)+)+  did not notice that the outer group could match an empty string.
1295      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
1296      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
1298  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
1299      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
1300      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
1302  13. Be more explicit in pcre_study() instead of relying on "default" for  13. Be more explicit in pcre_study() instead of relying on "default" for
1303      opcodes that mean there is no starting character; this means that when new      opcodes that mean there is no starting character; this means that when new
1304      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
1305      pick them up.      pick them up.
1307  14. The -s option of pcretest has been documented for ages as being an old  14. The -s option of pcretest has been documented for ages as being an old
1308      synonym of -m (show memory usage). I have changed it to mean "force study      synonym of -m (show memory usage). I have changed it to mean "force study
1309      for every regex", that is, assume /S for every regex. This is similar to -i      for every regex", that is, assume /S for every regex. This is similar to -i
1310      and -d etc. It's slightly incompatible, but I'm hoping nobody is still      and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1311      using it. It makes it easier to run collection of tests with study enabled,      using it. It makes it easier to run collections of tests with and without
1312      and thereby test pcre_study() more easily.      study enabled, and thereby test pcre_study() more easily. All the standard
1313        tests are now run with and without -s (but some patterns can be marked as
1314        "never study" - see 20 below).
1316  15. When (*ACCEPT) was used in a subpattern that was called recursively, the  15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1317      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
1318      correctly.      correctly.
1320  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1321      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1322      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
1323      match.      match.
1325    17. There was optimizing code for the last branch of non-capturing parentheses,
1326        and also for the obeyed branch of a conditional subexpression, which used
1327        tail recursion to cut down on stack usage. Unfortunately, now that there is
1328        the possibility of (*THEN) occurring in these branches, tail recursion is
1329        no longer possible because the return has to be checked for (*THEN). These
1330        two optimizations have therefore been removed. [But see 8.20/11 above.]
1332    18. If a pattern containing \R was studied, it was assumed that \R always
1333        matched two bytes, thus causing the minimum subject length to be
1334        incorrectly computed because \R can also match just one byte.
1336    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1337        was incorrectly computed.
1339    20. If /S is present twice on a test pattern in pcretest input, it now
1340        *disables* studying, thereby overriding the use of -s on the command line
1341        (see 14 above). This is necessary for one or two tests to keep the output
1342        identical in both cases.
1344    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1345        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1347    22. When an atomic group that contained a capturing parenthesis was
1348        successfully matched, but the branch in which it appeared failed, the
1349        capturing was not being forgotten if a higher numbered group was later
1350        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1351        group 1 to "a", when in fact it should be unset. This applied to multi-
1352        branched capturing and non-capturing groups, repeated or not, and also to
1353        positive assertions (capturing in negative assertions does not happen
1354        in PCRE) and also to nested atomic groups.
1356    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1357        subject after a captured substring, to make it easier to tell which of a
1358        number of identical substrings has been captured.
1360    24. The way atomic groups are processed by pcre_exec() has been changed so that
1361        if they are repeated, backtracking one repetition now resets captured
1362        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1363        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1364        "aaa". Previously, it would have been "a". As part of this code
1365        refactoring, the way recursive calls are handled has also been changed.
1367    25. If an assertion condition captured any substrings, they were not passed
1368        back unless some other capturing happened later. For example, if
1369        (?(?=(a))a) was matched against "a", no capturing was returned.
1371    26. When studying a pattern that contained subroutine calls or assertions,
1372        the code for finding the minimum length of a possible match was handling
1373        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1374        group 1 called group 2 while simultaneously a separate group 2 called group
1375        1). A stack overflow occurred in this case. I have fixed this by limiting
1376        the recursion depth to 10.
1378    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1379        Fortmann. This supports explicit test numbers on the command line, and has
1380        argument validation and error reporting.
1382    28. An instance of \X with an unlimited repeat could fail if at any point the
1383        first character it looked at was a mark character.
1385    29. Some minor code refactoring concerning Unicode properties and scripts
1386        should reduce the stack requirement of match() slightly.
1388    30. Added the '=' option to pcretest to check the setting of unused capturing
1389        slots at the end of the pattern, which are documented as being -1, but are
1390        not included in the return count.
1392    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1393        compiled something random. Now it gives a compile-time error (as does
1394        Perl).
1396    32. A *MARK encountered during the processing of a positive assertion is now
1397        recorded and passed back (compatible with Perl).
1399    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1400        had alternative anchored branches, the search for a second match in a line
1401        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1402        matched the line "0102" twice. The same bug affected patterns that started
1403        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1404        twice.
1406    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1407        does, and because of capturing effects, quantifying parenthesized
1408        assertions may at times be useful. Quantifiers are now allowed for
1409        parenthesized assertions.
1411    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1413    36. \g was being checked for fancy things in a character class, when it should
1414        just be a literal "g".
1416    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1417        appearance of a nested POSIX class supersedes an apparent external class.
1418        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1419        unescaped square brackets may also appear as part of class names. For
1420        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1421        more like Perl. (But see 8.20/1 above.)
1423    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1424        was because it thought it was \N{name}, which is not supported).
1426    39. Add minix to OS list not supporting the -S option in pcretest.
1428    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1429        cannot analyze patterns in sufficient detail to catch mutual recursions
1430        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1431        subgroup is called recursively as a subpattern for a second time at the
1432        same position in the subject string. In previous releases this might have
1433        been caught by the recursion limit, or it might have run out of stack.
1435    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1436        happen only once. PCRE was, however incorrectly giving a compile time error
1437        "recursive call could loop indefinitely" because it cannot analyze the
1438        pattern in sufficient detail. The compile time test no longer happens when
1439        PCRE is compiling a conditional subpattern, but actual runaway loops are
1440        now caught at runtime (see 40 above).
1442    42. It seems that Perl allows any characters other than a closing parenthesis
1443        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1444        has been changed to be the same.
1446    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1447        as not to get warnings when autogen.sh is called. Also changed
1448        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1450    44. To help people who use pcregrep to scan files containing exceedingly long
1451        lines, the following changes have been made:
1453        (a) The default value of the buffer size parameter has been increased from
1454            8K to 20K. (The actual buffer used is three times this size.)
1456        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1457            PCRE is built.
1459        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1460            to be set at run time.
1462        (d) Numerical values in pcregrep options can be followed by K or M, for
1463            example --buffer-size=50K.
1465        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1466            given and the return code is set to 2.
1468    45. Add a pointer to the latest mark to the callout data block.
1470    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1471        partial match of an empty string instead of no match. This was specific to
1472        the use of ".".
1474    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1475        complete match instead of a partial match. This bug was dependent on both
1476        the PCRE_UTF8 and PCRE_DOTALL options being set.
1478    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1479        starting byte set, because \b was not being ignored.
1482  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
1483  ------------------------  ------------------------
# Line 742  Version 7.9 11-Apr-09 Line 2129  Version 7.9 11-Apr-09
2129  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
2130      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
2131      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2132      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2133        8.33.]
2135  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
2136      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 985  Version 7.7 07-May-08 Line 2373  Version 7.7 07-May-08
2373      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2374      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2375      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2376      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2377      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2378      was subsequently set up correctly.)      was subsequently set up correctly.)

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