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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.13 02-Aug-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.
31    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
32        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
34    8. When a pattern is compiled, it remembers the highest back reference so that
35       when matching, if the ovector is too small, extra memory can be obtained to
36       use instead. A conditional subpattern whose condition is a check on a
37       capture having happened, such as, for example in the pattern
38       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
39       setting the highest backreference number. This mattered only if pcre_exec()
40       was called with an ovector that was too small to hold the capture, and there
41       was no other kind of back reference (a situation which is probably quite
42       rare). The effect of the bug was that the condition was always treated as
43       FALSE when the capture could not be consulted, leading to a incorrect
44       behaviour by pcre2_match(). This bug has been fixed.
46    9. A reference to a duplicated named group (either a back reference or a test
47       for being set in a conditional) that occurred in a part of the pattern where
48       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
49       to be incorrectly calculated, leading to overwriting.
51    10. A mutually recursive set of back references such as (\2)(\1) caused a
52        segfault at study time (while trying to find the minimum matching length).
53        The infinite loop is now broken (with the minimum length unset, that is,
54        zero).
56    11. If an assertion that was used as a condition was quantified with a minimum
57        of zero, matching went wrong. In particular, if the whole group had
58        unlimited repetition and could match an empty string, a segfault was
59        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
60        assertions to be quantified, but not if they are being used as conditions,
61        so the above pattern is faulted by Perl. PCRE has now been changed so that
62        it also rejects such patterns.
64    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
65        failed to allow the zero-repeat case if pcre2_exec() was called with an
66        ovector too small to capture the group.
68    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
69        Red Hat Product Security:
71        (a) A crash if /K and /F were both set with the option to save the compiled
72        pattern.
74        (b) Another crash if the option to print captured substrings in a callout
75        was combined with setting a null ovector, for example \O\C+ as a subject
76        string.
78    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
79        forward reference repeated a large (but limited) number of times within a
80        repeated outer group that has a zero minimum quantifier, caused incorrect
81        code to be compiled, leading to the error "internal error:
82        previously-checked referenced subpattern not found" when an incorrect
83        memory address was read. This bug was reported as "heap overflow",
84        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
85        CVE-2015-2325.
87    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
88        call within a group that also contained a recursive back reference caused
89        incorrect code to be compiled. This bug was reported as "heap overflow",
90        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
91        number CVE-2015-2326.
93    24. Computing the size of the JIT read-only data in advance has been a source
94        of various issues, and new ones are still appear unfortunately. To fix
95        existing and future issues, size computation is eliminated from the code,
96        and replaced by on-demand memory allocation.
98    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
99        adjacent to the end of the range, and the range contained characters with
100        more than one other case, caused incorrect behaviour when compiled in UTF
101        mode. In that example, the range a-j was left out of the class.
103    26. Fix JIT compilation of conditional blocks, which assertion
104        is converted to (*FAIL). E.g: /(?(?!))/.
106    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
107        discovered by the LLVM fuzzer.
109    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
110        when this assertion was used as a condition, for example (?(?!)a|b). In
111        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
112        error about an unsupported item.
114    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
115        possessification code could take exponential time to complete. A recursion
116        depth limit of 1000 has been imposed to limit the resources used by this
117        optimization.
119    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
120        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
121        because \S ensures they are all in the class. The code for doing this was
122        interacting badly with the code for computing the amount of space needed to
123        compile the pattern, leading to a buffer overflow. This bug was discovered
124        by the LLVM fuzzer.
126    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
127        other kinds of group caused stack overflow at compile time. This bug was
128        discovered by the LLVM fuzzer.
130    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
131        between a subroutine call and its quantifier was incorrectly compiled,
132        leading to buffer overflow or other errors. This bug was discovered by the
133        LLVM fuzzer.
135    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
136        assertion after (?(. The code was failing to check the character after
137        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
138        was discovered by the LLVM fuzzer.
140    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
141        a fixed maximum following a group that contains a subroutine reference was
142        incorrectly compiled and could trigger buffer overflow. This bug was
143        discovered by the LLVM fuzzer.
145    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
146        caused a stack overflow instead of the diagnosis of a non-fixed length
147        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
150    Version 8.36 26-September-2014
151    ------------------------------
153    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
154        -Wmissing-field-initializers and -Wunused-parameter.
156    2.  The tests for quantifiers being too big (greater than 65535) were being
157        applied after reading the number, and stupidly assuming that integer
158        overflow would give a negative number. The tests are now applied as the
159        numbers are read.
161    3.  Tidy code in pcre_exec.c where two branches that used to be different are
162        now the same.
164    4.  The JIT compiler did not generate match limit checks for certain
165        bracketed expressions with quantifiers. This may lead to exponential
166        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
167        issue should be resolved now.
169    5.  Fixed an issue, which occures when nested alternatives are optimized
170        with table jumps.
172    6.  Inserted two casts and changed some ints to size_t in the light of some
173        reported 64-bit compiler warnings (Bugzilla 1477).
175    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
176        an empty string, which sometimes were behaving incorrectly in the
177        interpreter (though correctly in the JIT matcher). This pcretest input is
178        an example:
180          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
183        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
184        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
185        for an empty string was breaking the inner loop and carrying on at a lower
186        level, when possessive repeated groups should always return to a higher
187        level as they have no backtrack points in them. The empty string test now
188        occurs at the outer level.
190    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
191        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
193    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
194        doesn't).
196    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
197        to hold a pattern to be incorrectly computed (too small) when there were
198        named back references to duplicated names. This could cause "internal
199        error: code overflow" or "double free or corruption" or other memory
200        handling errors.
202    11. When named subpatterns had the same prefixes, back references could be
203        confused. For example, in this pattern:
205          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
207        the reference to 'Name' was incorrectly treated as a reference to a
208        duplicate name.
210    12. A pattern such as /^s?c/mi8 where the optional character has more than
211        one "other case" was incorrectly compiled such that it would only try to
212        match starting at "c".
214    13. When a pattern starting with \s was studied, VT was not included in the
215        list of possible starting characters; this should have been part of the
216        8.34/18 patch.
218    14. If a character class started [\Qx]... where x is any character, the class
219        was incorrectly terminated at the ].
221    15. If a pattern that started with a caseless match for a character with more
222        than one "other case" was studied, PCRE did not set up the starting code
223        unit bit map for the list of possible characters. Now it does. This is an
224        optimization improvement, not a bug fix.
226    16. The Unicode data tables have been updated to Unicode 7.0.0.
228    17. Fixed a number of memory leaks in pcregrep.
230    18. Avoid a compiler warning (from some compilers) for a function call with
231        a cast that removes "const" from an lvalue by using an intermediate
232        variable (to which the compiler does not object).
234    19. Incorrect code was compiled if a group that contained an internal recursive
235        back reference was optional (had quantifier with a minimum of zero). This
236        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
237        caused segmentation faults because of stack overflows at compile time.
239    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
240        group that is quantified with an indefinite repeat, caused a compile-time
241        loop which used up all the system stack and provoked a segmentation fault.
242        This was not the same bug as 19 above.
244    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
245        Patch by Mike Frysinger.
248    Version 8.35 04-April-2014
249    --------------------------
251    1.  A new flag is set, when property checks are present in an XCLASS.
252        When this flag is not set, PCRE can perform certain optimizations
253        such as studying these XCLASS-es.
255    2.  The auto-possessification of character sets were improved: a normal
256        and an extended character set can be compared now. Furthermore
257        the JIT compiler optimizes more character set checks.
259    3.  Got rid of some compiler warnings for potentially uninitialized variables
260        that show up only when compiled with -O2.
262    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
263        of a match later then the end of the match. The pcretest program was not
264        handling the case sensibly - it was outputting from the start to the next
265        binary zero. It now reports this situation in a message, and outputs the
266        text from the end to the start.
268    5.  Fast forward search is improved in JIT. Instead of the first three
269        characters, any three characters with fixed position can be searched.
270        Search order: first, last, middle.
272    6.  Improve character range checks in JIT. Characters are read by an inprecise
273        function now, which returns with an unknown value if the character code is
274        above a certain threshold (e.g: 256). The only limitation is that the value
275        must be bigger than the threshold as well. This function is useful when
276        the characters above the threshold are handled in the same way.
278    7.  The macros whose names start with RAWUCHAR are placeholders for a future
279        mode in which only the bottom 21 bits of 32-bit data items are used. To
280        make this more memorable for those maintaining the code, the names have
281        been changed to start with UCHAR21, and an extensive comment has been added
282        to their definition.
284    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
285        to the export list in Makefile.am (they were accidentally omitted from the
286        8.34 tarball).
288    9.  The informational output from pcretest used the phrase "starting byte set"
289        which is inappropriate for the 16-bit and 32-bit libraries. As the output
290        for "first char" and "need char" really means "non-UTF-char", I've changed
291        "byte" to "char", and slightly reworded the output. The documentation about
292        these values has also been (I hope) clarified.
294    10. Another JIT related optimization: use table jumps for selecting the correct
295        backtracking path, when more than four alternatives are present inside a
296        bracket.
298    11. Empty match is not possible, when the minimum length is greater than zero,
299        and there is no \K in the pattern. JIT should avoid empty match checks in
300        such cases.
302    12. In a caseless character class with UCP support, when a character with more
303        than one alternative case was not the first character of a range, not all
304        the alternative cases were added to the class. For example, s and \x{17f}
305        are both alternative cases for S: the class [RST] was handled correctly,
306        but [R-T] was not.
308    13. The configure.ac file always checked for pthread support when JIT was
309        enabled. This is not used in Windows, so I have put this test inside a
310        check for the presence of windows.h (which was already tested for).
312    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
313        The algorithm provides a way to skip certain starting offsets, and usually
314        faster than linear prefix searches.
316    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
317        as for 'fr_FR' and 'french'. For some reason, however, it then used the
318        Windows-specific input and output files, which have 'french' screwed in.
319        So this could never have worked. One of the problems with locales is that
320        they aren't always the same. I have now updated RunTest so that it checks
321        the output of the locale test (test 3) against three different output
322        files, and it allows the test to pass if any one of them matches. With luck
323        this should make the test pass on some versions of Solaris where it was
324        failing. Because of the uncertainty, the script did not used to stop if
325        test 3 failed; it now does. If further versions of a French locale ever
326        come to light, they can now easily be added.
328    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
329        there was a message during ./configure, but it did not stop. This now
330        provokes an error. The invalid example in README has been corrected.
331        If a value less than the minimum is given, the minimum value has always
332        been used, but now a warning is given.
334    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
335        was a bug in the test system, which is now fixed. Also, the list of various
336        configurations that are tested for each release did not have one with both
337        16/32 bits and --enable-bar-anycrlf. It now does.
339    18. pcretest was missing "-C bsr" for displaying the \R default setting.
341    19. Little endian PowerPC systems are supported now by the JIT compiler.
343    20. The fast forward newline mechanism could enter to an infinite loop on
344        certain invalid UTF-8 input. Although we don't support these cases
345        this issue can be fixed by a performance optimization.
347    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
348        not take account if existing stack usage. There is now a new global
349        variable called pcre_stack_guard that can be set to point to an external
350        function to check stack availability. It is called at the start of
351        processing every parenthesized group.
353    22. A typo in the code meant that in ungreedy mode the max/min qualifier
354        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
355        not match "ab".
357    23. When UTF was disabled, the JIT program reported some incorrect compile
358        errors. These messages are silenced now.
360    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
361        compiler.
363    25. Change all the temporary files used in RunGrepTest to be different to those
364        used by RunTest so that the tests can be run simultaneously, for example by
365        "make -j check".
368    Version 8.34 15-December-2013
369    -----------------------------
371    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
372        executable memory. Patch inspired by Carsten Klein.
374    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
375        this macro is never tested and has no effect, because the work to support
376        coverage involves only compiling and linking options and special targets in
377        the Makefile. The comment in config.h implied that defining the macro would
378        enable coverage support, which is totally false. There was also support for
379        setting this macro in the CMake files (my fault, I just copied it from
380        configure). SUPPORT_GCOV has now been removed.
382    3.  Make a small performance improvement in strlen16() and strlen32() in
383        pcretest.
385    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
386        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
387        these cases). There was also one in pcretest.c.
389    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
391    6.  In UTF mode, the code for checking whether a group could match an empty
392        string (which is used for indefinitely repeated groups to allow for
393        breaking an infinite loop) was broken when the group contained a repeated
394        negated single-character class with a character that occupied more than one
395        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
396        UTF-8 mode). The effect was undefined: the group might or might not be
397        deemed as matching an empty string, or the program might have crashed.
399    7.  The code for checking whether a group could match an empty string was not
400        recognizing that \h, \H, \v, \V, and \R must match a character.
402    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
403        an empty string. If it can, pcretest shows this in its information output.
405    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
406        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
407        matched by pcre_exec() without using JIT:
409        (a) If the rest of the pattern did not match after a maximal run of
410            grapheme clusters, the code for backing up to try with fewer of them
411            did not always back up over a full grapheme when characters that do not
412            have the modifier quality were involved, e.g. Hangul syllables.
414        (b) If the match point in a subject started with modifier character, and
415            there was no match, the code could incorrectly back up beyond the match
416            point, and potentially beyond the first character in the subject,
417            leading to a segfault or an incorrect match result.
419    10. A conditional group with an assertion condition could lead to PCRE
420        recording an incorrect first data item for a match if no other first data
421        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
422        first data item, and therefore matched "ca" after "c" instead of at the
423        start.
425    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
426        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
428    12. The source of pcregrep now includes z/OS-specific code so that it can be
429        compiled for z/OS as part of the special z/OS distribution.
431    13. Added the -T and -TM options to pcretest.
433    14. The code in pcre_compile.c for creating the table of named capturing groups
434        has been refactored. Instead of creating the table dynamically during the
435        actual compiling pass, the information is remembered during the pre-compile
436        pass (on the stack unless there are more than 20 named groups, in which
437        case malloc() is used) and the whole table is created before the actual
438        compile happens. This has simplified the code (it is now nearly 150 lines
439        shorter) and prepared the way for better handling of references to groups
440        with duplicate names.
442    15. A back reference to a named subpattern when there is more than one of the
443        same name now checks them in the order in which they appear in the pattern.
444        The first one that is set is used for the reference. Previously only the
445        first one was inspected. This change makes PCRE more compatible with Perl.
447    16. Unicode character properties were updated from Unicode 6.3.0.
449    17. The compile-time code for auto-possessification has been refactored, based
450        on a patch by Zoltan Herczeg. It now happens after instead of during
451        compilation. The code is cleaner, and more cases are handled. The option
452        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
453        options in pcretest are provided to set it. It can also be set by
454        (*NO_AUTO_POSSESS) at the start of a pattern.
456    18. The character VT has been added to the default ("C" locale) set of
457        characters that match \s and are generally treated as white space,
458        following this same change in Perl 5.18. There is now no difference between
459        "Perl space" and "POSIX space". Whether VT is treated as white space in
460        other locales depends on the locale.
462    19. The code for checking named groups as conditions, either for being set or
463        for being recursed, has been refactored (this is related to 14 and 15
464        above). Processing unduplicated named groups should now be as fast at
465        numerical groups, and processing duplicated groups should be faster than
466        before.
468    20. Two patches to the CMake build system, by Alexander Barkov:
470          (1) Replace the "source" command by "." in CMakeLists.txt because
471              "source" is a bash-ism.
473          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
474              without these the CMake build does not work on Solaris.
476    21. Perl has changed its handling of \8 and \9. If there is no previously
477        encountered capturing group of those numbers, they are treated as the
478        literal characters 8 and 9 instead of a binary zero followed by the
479        literals. PCRE now does the same.
481    22. Following Perl, added \o{} to specify codepoints in octal, making it
482        possible to specify values greater than 0777 and also making them
483        unambiguous.
485    23. Perl now gives an error for missing closing braces after \x{... instead of
486        treating the string as literal. PCRE now does the same.
488    24. RunTest used to grumble if an inappropriate test was selected explicitly,
489        but just skip it when running all tests. This make it awkward to run ranges
490        of tests when one of them was inappropriate. Now it just skips any
491        inappropriate tests, as it always did when running all tests.
493    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
494        character types such as \d or \w, too many callouts were inserted, and the
495        data that they returned was rubbish.
497    26. In UCP mode, \s was not matching two of the characters that Perl matches,
498        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
499        were matched by \h. The code has now been refactored so that the lists of
500        the horizontal and vertical whitespace characters used for \h and \v (which
501        are defined only in one place) are now also used for \s.
503    27. Add JIT support for the 64 bit TileGX architecture.
504        Patch by Jiong Wang (Tilera Corporation).
506    28. Possessive quantifiers for classes (both explicit and automatically
507        generated) now use special opcodes instead of wrapping in ONCE brackets.
509    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
510        (because it's meaningless), this was not happening when PCRE_CASELESS was
511        set. Not wrong, but inefficient.
513    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
514        properties for \w, \d, etc) is present in a test regex. Otherwise if the
515        test contains no characters greater than 255, Perl doesn't realise it
516        should be using Unicode semantics.
518    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
519        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
520        does in Unicode mode.
522    32. Added the "forbid" facility to pcretest so that putting tests into the
523        wrong test files can sometimes be quickly detected.
525    33. There is now a limit (default 250) on the depth of nesting of parentheses.
526        This limit is imposed to control the amount of system stack used at compile
527        time. It can be changed at build time by --with-parens-nest-limit=xxx or
528        the equivalent in CMake.
530    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
531        errors. Perl warns for these when in warning mode, but PCRE has no facility
532        for giving warnings.
534    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
535        However, this was not working for (?!) because it is optimized to (*FAIL),
536        for which PCRE does not allow quantifiers. The optimization is now disabled
537        when a quantifier follows (?!). I can't see any use for this, but it makes
538        things uniform.
540    36. Perl no longer allows group names to start with digits, so I have made this
541        change also in PCRE. It simplifies the code a bit.
543    37. In extended mode, Perl ignores spaces before a + that indicates a
544        possessive quantifier. PCRE allowed a space before the quantifier, but not
545        before the possessive +. It now does.
547    38. The use of \K (reset reported match start) within a repeated possessive
548        group such as (a\Kb)*+ was not working.
550    40. Document that the same character tables must be used at compile time and
551        run time, and that the facility to pass tables to pcre_exec() and
552        pcre_dfa_exec() is for use only with saved/restored patterns.
554    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
555        features for Builds with MSVC:
557        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
558           builds). The .rc files can be used to set FileDescription and many other
559           attributes.
561        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
562           This allows higher-level build scripts which want .pdb files to avoid
563           hard-coding the exact files needed."
565    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
566        mean "start of word" and "end of word", respectively, as a transition aid.
568    43. A minimizing repeat of a class containing codepoints greater than 255 in
569        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
570        compiled to use the heap for recursion.
572    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
573        is configured.
576    Version 8.33 28-May-2013
577    ------------------------
579    1.  Added 'U' to some constants that are compared to unsigned integers, to
580        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
581        variables that are added to signed variables, to ensure the result is
582        signed and can be negated.
584    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
585        CMake config files.
587    3.  Revise the creation of config.h.generic so that all boolean macros are
588        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
589        overriding via -D on the command line possible.
591    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
592        to unsigned int is reported to make a quite noticeable speed difference in
593        a specific Windows environment. Testing on Linux did also appear to show
594        some benefit (and it is clearly not harmful). Also fixed the definition of
595        Xop which should be unsigned.
597    5.  Related to (4), changing the definition of the intermediate variable cc
598        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
599        improvements.
601    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
602        unnecessary spaces.
604    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
605        and later.
607    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
609    9.  Optimizing fast_forward_start_bits in JIT.
611    10. Adding support for callouts in JIT, and fixing some issues revealed
612        during this work. Namely:
614        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
616        (b) Minimum length was not checked before the matching is started.
618    11. The value of capture_last that is passed to callouts was incorrect in some
619        cases when there was a capture on one path that was subsequently abandoned
620        after a backtrack. Also, the capture_last value is now reset after a
621        recursion, since all captures are also reset in this case.
623    12. The interpreter no longer returns the "too many substrings" error in the
624        case when an overflowing capture is in a branch that is subsequently
625        abandoned after a backtrack.
627    13. In the pathological case when an offset vector of size 2 is used, pcretest
628        now prints out the matched string after a yield of 0 or 1.
630    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
631        Only supported by the JIT compiler at the moment.
633    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
635    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
636        offset of the starting point of the matching process, provided the offsets
637        vector is large enough.
639    17. The \A escape now records a lookbehind value of 1, though its execution
640        does not actually inspect the previous character. This is to ensure that,
641        in partial multi-segment matching, at least one character from the old
642        segment is retained when a new segment is processed. Otherwise, if there
643        are no lookbehinds in the pattern, \A might match incorrectly at the start
644        of a new segment.
646    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
648    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
649        gives some modest performance improvement in 8-bit mode.
651    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
652        be expressed in certain programming languages using Universal Character
653        Names.
655    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
656        which points out that "non characters" are not "characters that may not
657        appear in Unicode strings" but rather "characters that are reserved for
658        internal use and have only local meaning".
660    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
661        there was a conditional group that depended on an assertion, if the
662        assertion was false, the callout that immediately followed the alternation
663        in the condition was skipped when pcre_exec() was used for matching.
665    23. Allow an explicit callout to be inserted before an assertion that is the
666        condition for a conditional group, for compatibility with automatic
667        callouts, which always insert a callout at this point.
669    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
670        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
672    25. (*PRUNE) is now supported by the JIT compiler.
674    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
676    27. Fix the case where there are two or more SKIPs with arguments that may be
677        ignored.
679    28. (*SKIP) is now supported by the JIT compiler.
681    29. (*THEN) is now supported by the JIT compiler.
683    30. Update RunTest with additional test selector options.
685    31. The way PCRE handles backtracking verbs has been changed in two ways.
687        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
688        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
689        backtracking. In some cases this makes it more Perl-compatible, but Perl's
690        rather obscure rules do not always do the same thing.
692        (2) Previously, backtracking verbs were confined within assertions. This is
693        no longer the case for positive assertions, except for (*ACCEPT). Again,
694        this sometimes improves Perl compatibility, and sometimes does not.
696    32. A number of tests that were in test 2 because Perl did things differently
697        have been moved to test 1, because either Perl or PCRE has changed, and
698        these tests are now compatible.
700    32. Backtracking control verbs are now handled in the same way in JIT and
701        interpreter.
703    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
704        contained a forward subroutine reference caused a compile error.
706    34. Auto-detect and optimize limited repetitions in JIT.
708    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
709        blocking (*UTF) etc.
711    36. In the interpreter, maximizing pattern repetitions for characters and
712        character types now use tail recursion, which reduces stack usage.
714    37. The value of the max lookbehind was not correctly preserved if a compiled
715        and saved regex was reloaded on a host of different endianness.
717    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
718        of the compiled pattern block, expand the flags field from 16 to 32 bits
719        because it was almost full.
721    39. Try madvise first before posix_madvise.
723    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
724        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
725        original change locked out all matches of empty strings. This has been
726        changed so that one match of an empty string per line is recognized.
727        Subsequent searches on the same line (for colouring or for --only-matching,
728        for example) do not recognize empty strings.
730    41. Applied a user patch to fix a number of spelling mistakes in comments.
732    42. Data lines longer than 65536 caused pcretest to crash.
734    43. Clarified the data type for length and startoffset arguments for pcre_exec
735        and pcre_dfa_exec in the function-specific man pages, where they were
736        explicitly stated to be in bytes, never having been updated. I also added
737        some clarification to the pcreapi man page.
739    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
740        a segmentation fault.
743    Version 8.32 30-November-2012
744    -----------------------------
746    1.  Improved JIT compiler optimizations for first character search and single
747        character iterators.
749    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
750        Patch by Daniel Richard G.
752    3.  Single character iterator optimizations in the JIT compiler.
754    4.  Improved JIT compiler optimizations for character ranges.
756    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
757        Reported by Giuseppe D'Angelo.
759    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
760        of a line, was being set incorrectly in cases where .* appeared inside
761        atomic brackets at the start of a pattern, or where there was a subsequent
762        *PRUNE or *SKIP.
764    7.  Improved instruction cache flush for POWER/PowerPC.
765        Patch by Daniel Richard G.
767    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
768        grep:
770        (a) There is now no limit to the number of patterns to be matched.
772        (b) An error is given if a pattern is too long.
774        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
775            are now supported.
777        (d) --exclude-from and --include-from (multiple use) have been added.
779        (e) Exclusions and inclusions now apply to all files and directories, not
780            just to those obtained from scanning a directory recursively.
782        (f) Multiple uses of -f and --file-list are now supported.
784        (g) In a Windows environment, the default for -d has been changed from
785            "read" (the GNU grep default) to "skip", because otherwise the presence
786            of a directory in the file list provokes an error.
788        (h) The documentation has been revised and clarified in places.
790    9.  Improve the matching speed of capturing brackets.
792    10. Changed the meaning of \X so that it now matches a Unicode extended
793        grapheme cluster.
795    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
796        out POSIX threads when JIT support is configured.
798    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
800    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
801        structure could go wrong in environments where size_t is not the same size
802        as int.
804    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
805        set.
807    15. The EBCDIC support had decayed; later updates to the code had included
808        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
809        general tidy up of EBCDIC-related issues, and the documentation was also
810        not quite right. There is now a test that can be run on ASCII systems to
811        check some of the EBCDIC-related things (but is it not a full test).
813    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
814        in a small tidy to the code.
816    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
818    18. If the --only-matching (-o) option in pcregrep is specified multiple
819        times, each one causes appropriate output. For example, -o1 -o2 outputs the
820        substrings matched by the 1st and 2nd capturing parentheses. A separating
821        string can be specified by --om-separator (default empty).
823    19. Improving the first n character searches.
825    20. Turn case lists for horizontal and vertical white space into macros so that
826        they are defined only once.
828    21. This set of changes together give more compatible Unicode case-folding
829        behaviour for characters that have more than one other case when UCP
830        support is available.
832        (a) The Unicode property table now has offsets into a new table of sets of
833            three or more characters that are case-equivalent. The MultiStage2.py
834            script that generates these tables (the pcre_ucd.c file) now scans
835            CaseFolding.txt instead of UnicodeData.txt for character case
836            information.
838        (b) The code for adding characters or ranges of characters to a character
839            class has been abstracted into a generalized function that also handles
840            case-independence. In UTF-mode with UCP support, this uses the new data
841            to handle characters with more than one other case.
843        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
844            whose other case is greater than 256 are now correctly matched
845            caselessly. Previously, the high codepoint matched the low one, but not
846            vice versa.
848        (d) The processing of \h, \H, \v, and \ in character classes now makes use
849            of the new class addition function, using character lists defined as
850            macros alongside the case definitions of 20 above.
852        (e) Caseless back references now work with characters that have more than
853            one other case.
855        (f) General caseless matching of characters with more than one other case
856            is supported.
858    22. Unicode character properties were updated from Unicode 6.2.0
860    23. Improved CMake support under Windows. Patch by Daniel Richard G.
862    24. Add support for 32-bit character strings, and UTF-32
864    25. Major JIT compiler update (code refactoring and bugfixing).
865        Experimental Sparc 32 support is added.
867    26. Applied a modified version of Daniel Richard G's patch to create
868        pcre.h.generic and config.h.generic by "make" instead of in the
869        PrepareRelease script.
871    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
872        pcre_compile.c when checking for a zero character.
874    28. Introducing a native interface for JIT. Through this interface, the compiled
875        machine code can be directly executed. The purpose of this interface is to
876        provide fast pattern matching, so several sanity checks are not performed.
877        However, feature tests are still performed. The new interface provides
878        1.4x speedup compared to the old one.
880    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
881        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
882        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
884    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
885        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
886        the "old" RFC 2279). Instead, it ended up passing a negative length to
887        pcre_exec().
889    31. Add support for GCC's visibility feature to hide internal functions.
891    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
892        "unknown -C option" after outputting 0 or 1.
894    33. There is now support for generating a code coverage report for the test
895        suite in environments where gcc is the compiler and lcov is installed. This
896        is mainly for the benefit of the developers.
898    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
899        unaddressable using valgrind annotations, allowing valgrind to detect
900        invalid memory accesses. This is mainly for the benefit of the developers.
902    25. (*UTF) can now be used to start a pattern in any of the three libraries.
904    26. Give configure error if --enable-cpp but no C++ compiler found.
907    Version 8.31 06-July-2012
908    -------------------------
910    1.  Fixing a wrong JIT test case and some compiler warnings.
912    2.  Removed a bashism from the RunTest script.
914    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
915        to unsigned type, result still unsigned" that was given by an MS compiler
916        on encountering the code "-sizeof(xxx)".
918    4.  Partial matching support is added to the JIT compiler.
920    5.  Fixed several bugs concerned with partial matching of items that consist
921        of more than one character:
923        (a) /^(..)\1/ did not partially match "aba" because checking references was
924            done on an "all or nothing" basis. This also applied to repeated
925            references.
927        (b) \R did not give a hard partial match if \r was found at the end of the
928            subject.
930        (c) \X did not give a hard partial match after matching one or more
931            characters at the end of the subject.
933        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
934            a partial match for the string "\r".
936        (e) When newline was set to CRLF, the metacharacter "." did not recognize
937            a partial match for a CR character at the end of the subject string.
939    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
940        running pcretest, the text "(JIT)" added to the output whenever JIT is
941        actually used to run the match.
943    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
944        or /S+[+] with a digit between 1 and 7.
946    8.  OP_NOT now supports any UTF character not just single-byte ones.
948    9.  (*MARK) control verb is now supported by the JIT compiler.
950    10. The command "./RunTest list" lists the available tests without actually
951        running any of them. (Because I keep forgetting what they all are.)
955    12. Applied a (slightly modified) user-supplied patch that improves performance
956        when the heap is used for recursion (compiled with --disable-stack-for-
957        recursion). Instead of malloc and free for each heap frame each time a
958        logical recursion happens, frames are retained on a chain and re-used where
959        possible. This sometimes gives as much as 30% improvement.
961    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
962        call.
964    14. As documented, (*COMMIT) is now confined to within a positive assertion.
966    15. It is now possible to link pcretest with libedit as an alternative to
967        libreadline.
969    16. (*COMMIT) control verb is now supported by the JIT compiler.
971    17. The Unicode data tables have been updated to Unicode 6.1.0.
973    18. Added --file-list option to pcregrep.
975    19. Added binary file support to pcregrep, including the -a, --binary-files,
976        -I, and --text options.
978    20. The madvise function is renamed for posix_madvise for QNX compatibility
979        reasons. Fixed by Giuseppe D'Angelo.
981    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
983    22. Changed the option for creating symbolic links for 16-bit man pages from
984        -s to -sf so that re-installing does not cause issues.
986    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
988    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
989        matches in certain environments (the workspace was not being correctly
990        retained). Also added to pcre_dfa_exec() a simple plausibility check on
991        some of the workspace data at the beginning of a restart.
993    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
994        was not doing so when it should - probably a typo introduced by SVN 528
995        (change 8.10/14).
997    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
998        \w+ when the character tables indicated that \x{c4} was a word character.
999        There were several related cases, all because the tests for doing a table
1000        lookup were testing for characters less than 127 instead of 255.
1002    27. If a pattern contains capturing parentheses that are not used in a match,
1003        their slots in the ovector are set to -1. For those that are higher than
1004        any matched groups, this happens at the end of processing. In the case when
1005        there were back references that the ovector was too small to contain
1006        (causing temporary malloc'd memory to be used during matching), and the
1007        highest capturing number was not used, memory off the end of the ovector
1008        was incorrectly being set to -1. (It was using the size of the temporary
1009        memory instead of the true size.)
1011    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
1012        ovector size, it uses memory at the end of the block that it has got.
1014    29. Check for an overlong MARK name and give an error at compile time. The
1015        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
1017    30. JIT compiler update.
1019    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
1020        Rill for the patch.
1022    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
1024    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
1026    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
1027        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
1028        was enabled.
1030    35. Improve JIT code generation for greedy plus quantifier.
1032    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
1033        1 to "aa" instead of to an empty string. The bug affected repeated groups
1034        that could potentially match an empty string.
1036    37. Optimizing single character iterators in JIT.
1038    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
1039        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
1040        codepoints that are too big for the mode are faulted, and in a UTF mode,
1041        disallowed codepoints are also faulted.
1043    39. If PCRE was compiled with UTF support, in three places in the DFA
1044        matcher there was code that should only have been obeyed in UTF mode, but
1045        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
1046        processing when bytes with values greater than 127 were present. In 16-bit
1047        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
1048        both cases the values are those that cannot be the first data item in a UTF
1049        character. The three items that might have provoked this were recursions,
1050        possessively repeated groups, and atomic groups.
1052    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
1053        and pcregrep, because some OS require shared objects to be explicitly
1054        passed to ld, causing the link step to fail if they are not.
1056    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
1057        mode, patterns that started with \h* or \R* might be incorrectly matched.
1060    Version 8.30 04-February-2012
1061    -----------------------------
1063    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1064        name is defined in ctype.h.
1066    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1067        only in quite long subpatterns.
1069    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1070        since it was replaced by pcre_fullinfo() in February 2000.
1072    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1073        match a (*MARK), and the match failed at the start of the subject, a
1074        reference to memory before the start of the subject could occur. This bug
1075        was introduced by fix 17 of release 8.21.
1077    5.  A reference to an unset group with zero minimum repetition was giving
1078        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1079        /(another)?(\1?)test/ matched against "hello world test". This bug was
1080        introduced in release 8.13.
1082    6.  Add support for 16-bit character strings (a large amount of work involving
1083        many changes and refactorings).
1085    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1086        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1087        from a file.
1089    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1090        rounding is not applied in this particular case).
1092    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1093        if they appear, or are escaped, in patterns.
1095    10. Get rid of a number of -Wunused-but-set-variable warnings.
1097    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1098        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1099        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1100        also returns the mark "x". This bug applied to capturing parentheses,
1101        non-capturing parentheses, and atomic parentheses. It also applied to some
1102        assertions.
1104    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1105        information out of configure.ac instead of relying on pcre.h.generic, which
1106        is not stored in the repository.
1108    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1109        -lreadline.
1111    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1113    15. Applied Graycode's patch to put the top-level frame on the stack rather
1114        than the heap when not using the stack for recursion. This gives a
1115        performance improvement in many cases when recursion is not deep.
1117    16. Experimental code added to "pcretest -C" to output the stack frame size.
1120    Version 8.21 12-Dec-2011
1121    ------------------------
1123    1.  Updating the JIT compiler.
1125    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1126        are added as well.
1128    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1129        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1130        calling _pcre_jit_exec. Some extra comments are added.
1132    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1133        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1134        was introduced by change 18 for 8.20.
1136    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1137        ECMA-262 standard.
1139    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1140        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1141        This bug was probably introduced by change 9 of 8.13.
1143    7.  While fixing 6 above, I noticed that a number of other items were being
1144        incorrectly rejected as "not fixed length". This arose partly because newer
1145        opcodes had not been added to the fixed-length checking code. I have (a)
1146        corrected the bug and added tests for these items, and (b) arranged for an
1147        error to occur if an unknown opcode is encountered while checking for fixed
1148        length instead of just assuming "not fixed length". The items that were
1149        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1150        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1151        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1153    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1154        being incorrectly compiled and would have given unpredicatble results.
1156    9.  A possessively repeated subpattern with minimum repeat count greater than
1157        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1158        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1159        the first (A) could occur when it should not.
1161    10. Add a cast and remove a redundant test from the code.
1163    11. JIT should use pcre_malloc/pcre_free for allocation.
1165    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1166        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1167        is anything other than /usr, -L is still shown).
1169    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1171    14. Perl does not support \N without a following name in a [] class; PCRE now
1172        also gives an error.
1174    15. If a forward reference was repeated with an upper limit of around 2000,
1175        it caused the error "internal error: overran compiling workspace". The
1176        maximum number of forward references (including repeats) was limited by the
1177        internal workspace, and dependent on the LINK_SIZE. The code has been
1178        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1179        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1180        of around 200,000 forward references. While doing this, I also speeded up
1181        the filling in of repeated forward references.
1183    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1184        incorrectly expecting the subject to contain another "a" after the start.
1186    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1187        in the match, the SKIP should be ignored. This was not happening; instead
1188        the SKIP was being treated as NOMATCH. For patterns such as
1189        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1190        tested.
1192    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1193        now much more compatible with Perl, in particular in cases where the result
1194        is a non-match for a non-anchored pattern. For example, if
1195        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1196        "m", where previously it did not return a name. A side effect of this
1197        change is that for partial matches, the last encountered mark name is
1198        returned, as for non matches. A number of tests that were previously not
1199        Perl-compatible have been moved into the Perl-compatible test files. The
1200        refactoring has had the pleasing side effect of removing one argument from
1201        the match() function, thus reducing its stack requirements.
1203    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1204        subsequent uses of /S (without +) incorrectly behaved like /S+.
1206    21. Retrieve executable code size support for the JIT compiler and fixing
1207        some warnings.
1209    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1210        not work when the shorter character appeared right at the end of the
1211        subject string.
1213    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1214        systems.
1216    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1217        output it when the /M option is used in pcretest.
1219    25. The CheckMan script was not being included in the distribution. Also, added
1220        an explicit "perl" to run Perl scripts from the PrepareRelease script
1221        because this is reportedly needed in Windows.
1223    26. If study data was being save in a file and studying had not found a set of
1224        "starts with" bytes for the pattern, the data written to the file (though
1225        never used) was taken from uninitialized memory and so caused valgrind to
1226        complain.
1228    27. Updated RunTest.bat as provided by Sheri Pierce.
1230    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1232    29. Computation of memory usage for the table of capturing group names was
1233        giving an unnecessarily large value.
1236    Version 8.20 21-Oct-2011
1237    ------------------------
1239    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1240        a POSIX class. After further experiments with Perl, which convinced me that
1241        Perl has bugs and confusions, a closing square bracket is no longer allowed
1242        in a POSIX name. This bug also affected patterns with classes that started
1243        with full stops.
1245    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1246        captured substring, but while checking the failing first alternative,
1247        substring 1 is temporarily captured. If the output vector supplied to
1248        pcre_exec() was not big enough for this capture, the yield of the function
1249        was still zero ("insufficient space for captured substrings"). This cannot
1250        be totally fixed without adding another stack variable, which seems a lot
1251        of expense for a edge case. However, I have improved the situation in cases
1252        such as /(a)(b)x|abc/ matched against "abc", where the return code
1253        indicates that fewer than the maximum number of slots in the ovector have
1254        been set.
1256    3.  Related to (2) above: when there are more back references in a pattern than
1257        slots in the output vector, pcre_exec() uses temporary memory during
1258        matching, and copies in the captures as far as possible afterwards. It was
1259        using the entire output vector, but this conflicts with the specification
1260        that only 2/3 is used for passing back captured substrings. Now it uses
1261        only the first 2/3, for compatibility. This is, of course, another edge
1262        case.
1264    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1265        main code base, and can be used by building with --enable-jit. When this is
1266        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1267        runtime --no-jit option is given.
1269    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1270        ovector, the return from the function was zero, implying that there were
1271        other matches that did not fit. The correct "exactly full" value is now
1272        returned.
1274    6.  If a subpattern that was called recursively or as a subroutine contained
1275        (*PRUNE) or any other control that caused it to give a non-standard return,
1276        invalid errors such as "Error -26 (nested recursion at the same subject
1277        position)" or even infinite loops could occur.
1279    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1280        computing the minimum length on reaching *ACCEPT, and so ended up with the
1281        wrong value of 1 rather than 0. Further investigation indicates that
1282        computing a minimum subject length in the presence of *ACCEPT is difficult
1283        (think back references, subroutine calls), and so I have changed the code
1284        so that no minimum is registered for a pattern that contains *ACCEPT.
1286    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1287        it was not handled as intended. [But see 16 below.]
1289    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1290        Sheri Pierce.
1292    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1293        the first byte in a match must be "a".
1295    11. Change 17 for 8.13 increased the recursion depth for patterns like
1296        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1297        pattern contains any instances of (*THEN). If it does not, the old
1298        optimizations are restored. It would be nice to do this on a per-group
1299        basis, but at the moment that is not feasible.
1301    12. In some environments, the output of pcretest -C is CRLF terminated. This
1302        broke RunTest's code that checks for the link size. A single white space
1303        character after the value is now allowed for.
1305    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1306        For "fr", it uses the Windows-specific input and output files.
1308    14. If (*THEN) appeared in a group that was called recursively or as a
1309        subroutine, it did not work as intended. [But see next item.]
1311    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1312        pattern fragments (but not containing any | characters). If A and B are
1313        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1314        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1315        D. In other words, Perl considers parentheses that do not contain any |
1316        characters to be part of a surrounding alternative, whereas PCRE was
1317        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1318        differently. PCRE now behaves in the same way as Perl, except in the case
1319        of subroutine/recursion calls such as (?1) which have in any case always
1320        been different (but PCRE had them first :-).
1322    16. Related to 15 above: Perl does not treat the | in a conditional group as
1323        creating alternatives. Such a group is treated in the same way as an
1324        ordinary group without any | characters when processing (*THEN). PCRE has
1325        been changed to match Perl's behaviour.
1327    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1328        RunGrepTest script failed.
1330    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1331        inevitable for groups that contain captures, but it can lead to a lot of
1332        stack use in large patterns. The old behaviour has been restored for atomic
1333        groups that do not contain any capturing parentheses.
1335    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1336        suppress the check for a minimum subject length at run time. (If it was
1337        given to pcre_exec() or pcre_dfa_exec() it did work.)
1339    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1340        fail to work when decoding hex characters in data strings in EBCDIC
1341        environments.
1343    21. It appears that in at least one Mac OS environment, the isxdigit() function
1344        is implemented as a macro that evaluates to its argument more than once,
1345        contravening the C 90 Standard (I haven't checked a later standard). There
1346        was an instance in pcretest which caused it to go wrong when processing
1347        \x{...} escapes in subject strings. The has been rewritten to avoid using
1348        things like p++ in the argument of isxdigit().
1351    Version 8.13 16-Aug-2011
1352  ------------------------  ------------------------
1354  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 98  Version 8.13 02-Aug-2011 Line 1445  Version 8.13 02-Aug-2011
1445      tail recursion to cut down on stack usage. Unfortunately, now that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
1446      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
1447      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
1448      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
1450  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
1451      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
# Line 189  Version 8.13 02-Aug-2011 Line 1536  Version 8.13 02-Aug-2011
1536      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1537      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
1538      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1539      more like Perl.      more like Perl. (But see 8.20/1 above.)
1541  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1542      was because it thought it was \N{name}, which is not supported).      was because it thought it was \N{name}, which is not supported).
# Line 224  Version 8.13 02-Aug-2011 Line 1571  Version 8.13 02-Aug-2011
1571      (a) The default value of the buffer size parameter has been increased from      (a) The default value of the buffer size parameter has been increased from
1572          8K to 20K. (The actual buffer used is three times this size.)          8K to 20K. (The actual buffer used is three times this size.)
1574      (b) The default can be changed by ./configure --with-pcregrep-bufsiz when      (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1575          PCRE is built.          PCRE is built.
1577      (c) A --buffer-size=n option has been added to pcregrep, to allow the size      (c) A --buffer-size=n option has been added to pcregrep, to allow the size
# Line 245  Version 8.13 02-Aug-2011 Line 1592  Version 8.13 02-Aug-2011
1592  47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a  47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1593      complete match instead of a partial match. This bug was dependent on both      complete match instead of a partial match. This bug was dependent on both
1594      the PCRE_UTF8 and PCRE_DOTALL options being set.      the PCRE_UTF8 and PCRE_DOTALL options being set.
1596  48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the  48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1597      starting byte set, because \b was not being ignored.      starting byte set, because \b was not being ignored.
1600  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
# Line 900  Version 7.9 11-Apr-09 Line 2247  Version 7.9 11-Apr-09
2247  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
2248      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
2249      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2250      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2251        8.33.]
2253  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
2254      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 1143  Version 7.7 07-May-08 Line 2491  Version 7.7 07-May-08
2491      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2492      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2493      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2494      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2495      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2496      was subsequently set up correctly.)      was subsequently set up correctly.)

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  Added in v.1542

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