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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.02 01-Mar-2010  Version 8.38 xx-xxx-xxxx
5    ------------------------
7    1.  If a group that contained a recursive back reference also contained a
8        forward reference subroutine call followed by a non-forward-reference
9        subroutine call, for example /.((?2)(?R)\1)()/, pcre2_compile() failed to
10        compile correct code, leading to undefined behaviour or an internally
11        detected error. This bug was discovered by the LLVM fuzzer.
13    2.  Quantification of certain items (e.g. atomic back references) could cause
14        incorrect code to be compiled when recursive forward references were
15        involved. For example, in this pattern: /(?1)()((((((\1++))\x85)+)|))/.
16        This bug was discovered by the LLVM fuzzer.
18    3.  A repeated conditional group whose condition was a reference by name caused
19        a buffer overflow if there was more than one group with the given name.
20        This bug was discovered by the LLVM fuzzer.
22    4.  A recursive back reference by name within a group that had the same name as
23        another group caused a buffer overflow. For example:
24        /(?J)(?'d'(?'d'\g{d}))/. This bug was discovered by the LLVM fuzzer.
27    Version 8.37 28-April-2015
28    --------------------------
30    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
31        for those parentheses to be closed with whatever has been captured so far.
32        However, it was failing to mark any other groups between the hightest
33        capture so far and the currrent group as "unset". Thus, the ovector for
34        those groups contained whatever was previously there. An example is the
35        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
37    2.  If an assertion condition was quantified with a minimum of zero (an odd
38        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
40    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
41        unrecognized modifier, a crash could occur.
43    4.  An attempt to do global matching in pcretest with a zero-length ovector
44        caused a crash.
46    5.  Fixed a memory leak during matching that could occur for a subpattern
47        subroutine call (recursive or otherwise) if the number of captured groups
48        that had to be saved was greater than ten.
50    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
51        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
52        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
54    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
55        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
57    8. When a pattern is compiled, it remembers the highest back reference so that
58       when matching, if the ovector is too small, extra memory can be obtained to
59       use instead. A conditional subpattern whose condition is a check on a
60       capture having happened, such as, for example in the pattern
61       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
62       setting the highest backreference number. This mattered only if pcre_exec()
63       was called with an ovector that was too small to hold the capture, and there
64       was no other kind of back reference (a situation which is probably quite
65       rare). The effect of the bug was that the condition was always treated as
66       FALSE when the capture could not be consulted, leading to a incorrect
67       behaviour by pcre_exec(). This bug has been fixed.
69    9. A reference to a duplicated named group (either a back reference or a test
70       for being set in a conditional) that occurred in a part of the pattern where
71       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
72       to be incorrectly calculated, leading to overwriting.
74    10. A mutually recursive set of back references such as (\2)(\1) caused a
75        segfault at study time (while trying to find the minimum matching length).
76        The infinite loop is now broken (with the minimum length unset, that is,
77        zero).
79    11. If an assertion that was used as a condition was quantified with a minimum
80        of zero, matching went wrong. In particular, if the whole group had
81        unlimited repetition and could match an empty string, a segfault was
82        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
83        assertions to be quantified, but not if they are being used as conditions,
84        so the above pattern is faulted by Perl. PCRE has now been changed so that
85        it also rejects such patterns.
87    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
88        failed to allow the zero-repeat case if pcre2_exec() was called with an
89        ovector too small to capture the group.
91    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
92        Red Hat Product Security:
94        (a) A crash if /K and /F were both set with the option to save the compiled
95        pattern.
97        (b) Another crash if the option to print captured substrings in a callout
98        was combined with setting a null ovector, for example \O\C+ as a subject
99        string.
101    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
102        forward reference repeated a large (but limited) number of times within a
103        repeated outer group that has a zero minimum quantifier, caused incorrect
104        code to be compiled, leading to the error "internal error:
105        previously-checked referenced subpattern not found" when an incorrect
106        memory address was read. This bug was reported as "heap overflow",
107        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
108        CVE-2015-2325.
110    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
111        call within a group that also contained a recursive back reference caused
112        incorrect code to be compiled. This bug was reported as "heap overflow",
113        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
114        number CVE-2015-2326.
116    24. Computing the size of the JIT read-only data in advance has been a source
117        of various issues, and new ones are still appear unfortunately. To fix
118        existing and future issues, size computation is eliminated from the code,
119        and replaced by on-demand memory allocation.
121    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
122        adjacent to the end of the range, and the range contained characters with
123        more than one other case, caused incorrect behaviour when compiled in UTF
124        mode. In that example, the range a-j was left out of the class.
126    26. Fix JIT compilation of conditional blocks, which assertion
127        is converted to (*FAIL). E.g: /(?(?!))/.
129    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
130        discovered by the LLVM fuzzer.
132    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
133        when this assertion was used as a condition, for example (?(?!)a|b). In
134        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
135        error about an unsupported item.
137    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
138        possessification code could take exponential time to complete. A recursion
139        depth limit of 1000 has been imposed to limit the resources used by this
140        optimization.
142    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
143        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
144        because \S ensures they are all in the class. The code for doing this was
145        interacting badly with the code for computing the amount of space needed to
146        compile the pattern, leading to a buffer overflow. This bug was discovered
147        by the LLVM fuzzer.
149    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
150        other kinds of group caused stack overflow at compile time. This bug was
151        discovered by the LLVM fuzzer.
153    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
154        between a subroutine call and its quantifier was incorrectly compiled,
155        leading to buffer overflow or other errors. This bug was discovered by the
156        LLVM fuzzer.
158    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
159        assertion after (?(. The code was failing to check the character after
160        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
161        was discovered by the LLVM fuzzer.
163    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
164        a fixed maximum following a group that contains a subroutine reference was
165        incorrectly compiled and could trigger buffer overflow. This bug was
166        discovered by the LLVM fuzzer.
168    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
169        caused a stack overflow instead of the diagnosis of a non-fixed length
170        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
172    36. The use of \K in a positive lookbehind assertion in a non-anchored pattern
173        (e.g. /(?<=\Ka)/) could make pcregrep loop.
175    37. There was a similar problem to 36 in pcretest for global matches.
177    38. If a greedy quantified \X was preceded by \C in UTF mode (e.g. \C\X*),
178        and a subsequent item in the pattern caused a non-match, backtracking over
179        the repeated \X did not stop, but carried on past the start of the subject,
180        causing reference to random memory and/or a segfault. There were also some
181        other cases where backtracking after \C could crash. This set of bugs was
182        discovered by the LLVM fuzzer.
184    39. The function for finding the minimum length of a matching string could take
185        a very long time if mutual recursion was present many times in a pattern,
186        for example, /((?2){73}(?2))((?1))/. A better mutual recursion detection
187        method has been implemented. This infelicity was discovered by the LLVM
188        fuzzer.
190    40. Static linking against the PCRE library using the pkg-config module was
191        failing on missing pthread symbols.
194    Version 8.36 26-September-2014
195    ------------------------------
197    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
198        -Wmissing-field-initializers and -Wunused-parameter.
200    2.  The tests for quantifiers being too big (greater than 65535) were being
201        applied after reading the number, and stupidly assuming that integer
202        overflow would give a negative number. The tests are now applied as the
203        numbers are read.
205    3.  Tidy code in pcre_exec.c where two branches that used to be different are
206        now the same.
208    4.  The JIT compiler did not generate match limit checks for certain
209        bracketed expressions with quantifiers. This may lead to exponential
210        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
211        issue should be resolved now.
213    5.  Fixed an issue, which occures when nested alternatives are optimized
214        with table jumps.
216    6.  Inserted two casts and changed some ints to size_t in the light of some
217        reported 64-bit compiler warnings (Bugzilla 1477).
219    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
220        an empty string, which sometimes were behaving incorrectly in the
221        interpreter (though correctly in the JIT matcher). This pcretest input is
222        an example:
224          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
227        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
228        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
229        for an empty string was breaking the inner loop and carrying on at a lower
230        level, when possessive repeated groups should always return to a higher
231        level as they have no backtrack points in them. The empty string test now
232        occurs at the outer level.
234    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
235        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
237    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
238        doesn't).
240    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
241        to hold a pattern to be incorrectly computed (too small) when there were
242        named back references to duplicated names. This could cause "internal
243        error: code overflow" or "double free or corruption" or other memory
244        handling errors.
246    11. When named subpatterns had the same prefixes, back references could be
247        confused. For example, in this pattern:
249          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
251        the reference to 'Name' was incorrectly treated as a reference to a
252        duplicate name.
254    12. A pattern such as /^s?c/mi8 where the optional character has more than
255        one "other case" was incorrectly compiled such that it would only try to
256        match starting at "c".
258    13. When a pattern starting with \s was studied, VT was not included in the
259        list of possible starting characters; this should have been part of the
260        8.34/18 patch.
262    14. If a character class started [\Qx]... where x is any character, the class
263        was incorrectly terminated at the ].
265    15. If a pattern that started with a caseless match for a character with more
266        than one "other case" was studied, PCRE did not set up the starting code
267        unit bit map for the list of possible characters. Now it does. This is an
268        optimization improvement, not a bug fix.
270    16. The Unicode data tables have been updated to Unicode 7.0.0.
272    17. Fixed a number of memory leaks in pcregrep.
274    18. Avoid a compiler warning (from some compilers) for a function call with
275        a cast that removes "const" from an lvalue by using an intermediate
276        variable (to which the compiler does not object).
278    19. Incorrect code was compiled if a group that contained an internal recursive
279        back reference was optional (had quantifier with a minimum of zero). This
280        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
281        caused segmentation faults because of stack overflows at compile time.
283    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
284        group that is quantified with an indefinite repeat, caused a compile-time
285        loop which used up all the system stack and provoked a segmentation fault.
286        This was not the same bug as 19 above.
288    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
289        Patch by Mike Frysinger.
292    Version 8.35 04-April-2014
293    --------------------------
295    1.  A new flag is set, when property checks are present in an XCLASS.
296        When this flag is not set, PCRE can perform certain optimizations
297        such as studying these XCLASS-es.
299    2.  The auto-possessification of character sets were improved: a normal
300        and an extended character set can be compared now. Furthermore
301        the JIT compiler optimizes more character set checks.
303    3.  Got rid of some compiler warnings for potentially uninitialized variables
304        that show up only when compiled with -O2.
306    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
307        of a match later then the end of the match. The pcretest program was not
308        handling the case sensibly - it was outputting from the start to the next
309        binary zero. It now reports this situation in a message, and outputs the
310        text from the end to the start.
312    5.  Fast forward search is improved in JIT. Instead of the first three
313        characters, any three characters with fixed position can be searched.
314        Search order: first, last, middle.
316    6.  Improve character range checks in JIT. Characters are read by an inprecise
317        function now, which returns with an unknown value if the character code is
318        above a certain threshold (e.g: 256). The only limitation is that the value
319        must be bigger than the threshold as well. This function is useful when
320        the characters above the threshold are handled in the same way.
322    7.  The macros whose names start with RAWUCHAR are placeholders for a future
323        mode in which only the bottom 21 bits of 32-bit data items are used. To
324        make this more memorable for those maintaining the code, the names have
325        been changed to start with UCHAR21, and an extensive comment has been added
326        to their definition.
328    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
329        to the export list in Makefile.am (they were accidentally omitted from the
330        8.34 tarball).
332    9.  The informational output from pcretest used the phrase "starting byte set"
333        which is inappropriate for the 16-bit and 32-bit libraries. As the output
334        for "first char" and "need char" really means "non-UTF-char", I've changed
335        "byte" to "char", and slightly reworded the output. The documentation about
336        these values has also been (I hope) clarified.
338    10. Another JIT related optimization: use table jumps for selecting the correct
339        backtracking path, when more than four alternatives are present inside a
340        bracket.
342    11. Empty match is not possible, when the minimum length is greater than zero,
343        and there is no \K in the pattern. JIT should avoid empty match checks in
344        such cases.
346    12. In a caseless character class with UCP support, when a character with more
347        than one alternative case was not the first character of a range, not all
348        the alternative cases were added to the class. For example, s and \x{17f}
349        are both alternative cases for S: the class [RST] was handled correctly,
350        but [R-T] was not.
352    13. The configure.ac file always checked for pthread support when JIT was
353        enabled. This is not used in Windows, so I have put this test inside a
354        check for the presence of windows.h (which was already tested for).
356    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
357        The algorithm provides a way to skip certain starting offsets, and usually
358        faster than linear prefix searches.
360    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
361        as for 'fr_FR' and 'french'. For some reason, however, it then used the
362        Windows-specific input and output files, which have 'french' screwed in.
363        So this could never have worked. One of the problems with locales is that
364        they aren't always the same. I have now updated RunTest so that it checks
365        the output of the locale test (test 3) against three different output
366        files, and it allows the test to pass if any one of them matches. With luck
367        this should make the test pass on some versions of Solaris where it was
368        failing. Because of the uncertainty, the script did not used to stop if
369        test 3 failed; it now does. If further versions of a French locale ever
370        come to light, they can now easily be added.
372    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
373        there was a message during ./configure, but it did not stop. This now
374        provokes an error. The invalid example in README has been corrected.
375        If a value less than the minimum is given, the minimum value has always
376        been used, but now a warning is given.
378    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
379        was a bug in the test system, which is now fixed. Also, the list of various
380        configurations that are tested for each release did not have one with both
381        16/32 bits and --enable-bar-anycrlf. It now does.
383    18. pcretest was missing "-C bsr" for displaying the \R default setting.
385    19. Little endian PowerPC systems are supported now by the JIT compiler.
387    20. The fast forward newline mechanism could enter to an infinite loop on
388        certain invalid UTF-8 input. Although we don't support these cases
389        this issue can be fixed by a performance optimization.
391    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
392        not take account if existing stack usage. There is now a new global
393        variable called pcre_stack_guard that can be set to point to an external
394        function to check stack availability. It is called at the start of
395        processing every parenthesized group.
397    22. A typo in the code meant that in ungreedy mode the max/min qualifier
398        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
399        not match "ab".
401    23. When UTF was disabled, the JIT program reported some incorrect compile
402        errors. These messages are silenced now.
404    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
405        compiler.
407    25. Change all the temporary files used in RunGrepTest to be different to those
408        used by RunTest so that the tests can be run simultaneously, for example by
409        "make -j check".
412    Version 8.34 15-December-2013
413    -----------------------------
415    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
416        executable memory. Patch inspired by Carsten Klein.
418    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
419        this macro is never tested and has no effect, because the work to support
420        coverage involves only compiling and linking options and special targets in
421        the Makefile. The comment in config.h implied that defining the macro would
422        enable coverage support, which is totally false. There was also support for
423        setting this macro in the CMake files (my fault, I just copied it from
424        configure). SUPPORT_GCOV has now been removed.
426    3.  Make a small performance improvement in strlen16() and strlen32() in
427        pcretest.
429    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
430        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
431        these cases). There was also one in pcretest.c.
433    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
435    6.  In UTF mode, the code for checking whether a group could match an empty
436        string (which is used for indefinitely repeated groups to allow for
437        breaking an infinite loop) was broken when the group contained a repeated
438        negated single-character class with a character that occupied more than one
439        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
440        UTF-8 mode). The effect was undefined: the group might or might not be
441        deemed as matching an empty string, or the program might have crashed.
443    7.  The code for checking whether a group could match an empty string was not
444        recognizing that \h, \H, \v, \V, and \R must match a character.
446    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
447        an empty string. If it can, pcretest shows this in its information output.
449    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
450        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
451        matched by pcre_exec() without using JIT:
453        (a) If the rest of the pattern did not match after a maximal run of
454            grapheme clusters, the code for backing up to try with fewer of them
455            did not always back up over a full grapheme when characters that do not
456            have the modifier quality were involved, e.g. Hangul syllables.
458        (b) If the match point in a subject started with modifier character, and
459            there was no match, the code could incorrectly back up beyond the match
460            point, and potentially beyond the first character in the subject,
461            leading to a segfault or an incorrect match result.
463    10. A conditional group with an assertion condition could lead to PCRE
464        recording an incorrect first data item for a match if no other first data
465        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
466        first data item, and therefore matched "ca" after "c" instead of at the
467        start.
469    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
470        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
472    12. The source of pcregrep now includes z/OS-specific code so that it can be
473        compiled for z/OS as part of the special z/OS distribution.
475    13. Added the -T and -TM options to pcretest.
477    14. The code in pcre_compile.c for creating the table of named capturing groups
478        has been refactored. Instead of creating the table dynamically during the
479        actual compiling pass, the information is remembered during the pre-compile
480        pass (on the stack unless there are more than 20 named groups, in which
481        case malloc() is used) and the whole table is created before the actual
482        compile happens. This has simplified the code (it is now nearly 150 lines
483        shorter) and prepared the way for better handling of references to groups
484        with duplicate names.
486    15. A back reference to a named subpattern when there is more than one of the
487        same name now checks them in the order in which they appear in the pattern.
488        The first one that is set is used for the reference. Previously only the
489        first one was inspected. This change makes PCRE more compatible with Perl.
491    16. Unicode character properties were updated from Unicode 6.3.0.
493    17. The compile-time code for auto-possessification has been refactored, based
494        on a patch by Zoltan Herczeg. It now happens after instead of during
495        compilation. The code is cleaner, and more cases are handled. The option
496        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
497        options in pcretest are provided to set it. It can also be set by
498        (*NO_AUTO_POSSESS) at the start of a pattern.
500    18. The character VT has been added to the default ("C" locale) set of
501        characters that match \s and are generally treated as white space,
502        following this same change in Perl 5.18. There is now no difference between
503        "Perl space" and "POSIX space". Whether VT is treated as white space in
504        other locales depends on the locale.
506    19. The code for checking named groups as conditions, either for being set or
507        for being recursed, has been refactored (this is related to 14 and 15
508        above). Processing unduplicated named groups should now be as fast at
509        numerical groups, and processing duplicated groups should be faster than
510        before.
512    20. Two patches to the CMake build system, by Alexander Barkov:
514          (1) Replace the "source" command by "." in CMakeLists.txt because
515              "source" is a bash-ism.
517          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
518              without these the CMake build does not work on Solaris.
520    21. Perl has changed its handling of \8 and \9. If there is no previously
521        encountered capturing group of those numbers, they are treated as the
522        literal characters 8 and 9 instead of a binary zero followed by the
523        literals. PCRE now does the same.
525    22. Following Perl, added \o{} to specify codepoints in octal, making it
526        possible to specify values greater than 0777 and also making them
527        unambiguous.
529    23. Perl now gives an error for missing closing braces after \x{... instead of
530        treating the string as literal. PCRE now does the same.
532    24. RunTest used to grumble if an inappropriate test was selected explicitly,
533        but just skip it when running all tests. This make it awkward to run ranges
534        of tests when one of them was inappropriate. Now it just skips any
535        inappropriate tests, as it always did when running all tests.
537    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
538        character types such as \d or \w, too many callouts were inserted, and the
539        data that they returned was rubbish.
541    26. In UCP mode, \s was not matching two of the characters that Perl matches,
542        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
543        were matched by \h. The code has now been refactored so that the lists of
544        the horizontal and vertical whitespace characters used for \h and \v (which
545        are defined only in one place) are now also used for \s.
547    27. Add JIT support for the 64 bit TileGX architecture.
548        Patch by Jiong Wang (Tilera Corporation).
550    28. Possessive quantifiers for classes (both explicit and automatically
551        generated) now use special opcodes instead of wrapping in ONCE brackets.
553    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
554        (because it's meaningless), this was not happening when PCRE_CASELESS was
555        set. Not wrong, but inefficient.
557    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
558        properties for \w, \d, etc) is present in a test regex. Otherwise if the
559        test contains no characters greater than 255, Perl doesn't realise it
560        should be using Unicode semantics.
562    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
563        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
564        does in Unicode mode.
566    32. Added the "forbid" facility to pcretest so that putting tests into the
567        wrong test files can sometimes be quickly detected.
569    33. There is now a limit (default 250) on the depth of nesting of parentheses.
570        This limit is imposed to control the amount of system stack used at compile
571        time. It can be changed at build time by --with-parens-nest-limit=xxx or
572        the equivalent in CMake.
574    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
575        errors. Perl warns for these when in warning mode, but PCRE has no facility
576        for giving warnings.
578    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
579        However, this was not working for (?!) because it is optimized to (*FAIL),
580        for which PCRE does not allow quantifiers. The optimization is now disabled
581        when a quantifier follows (?!). I can't see any use for this, but it makes
582        things uniform.
584    36. Perl no longer allows group names to start with digits, so I have made this
585        change also in PCRE. It simplifies the code a bit.
587    37. In extended mode, Perl ignores spaces before a + that indicates a
588        possessive quantifier. PCRE allowed a space before the quantifier, but not
589        before the possessive +. It now does.
591    38. The use of \K (reset reported match start) within a repeated possessive
592        group such as (a\Kb)*+ was not working.
594    40. Document that the same character tables must be used at compile time and
595        run time, and that the facility to pass tables to pcre_exec() and
596        pcre_dfa_exec() is for use only with saved/restored patterns.
598    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
599        features for Builds with MSVC:
601        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
602           builds). The .rc files can be used to set FileDescription and many other
603           attributes.
605        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
606           This allows higher-level build scripts which want .pdb files to avoid
607           hard-coding the exact files needed."
609    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
610        mean "start of word" and "end of word", respectively, as a transition aid.
612    43. A minimizing repeat of a class containing codepoints greater than 255 in
613        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
614        compiled to use the heap for recursion.
616    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
617        is configured.
620    Version 8.33 28-May-2013
621    ------------------------
623    1.  Added 'U' to some constants that are compared to unsigned integers, to
624        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
625        variables that are added to signed variables, to ensure the result is
626        signed and can be negated.
628    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
629        CMake config files.
631    3.  Revise the creation of config.h.generic so that all boolean macros are
632        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
633        overriding via -D on the command line possible.
635    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
636        to unsigned int is reported to make a quite noticeable speed difference in
637        a specific Windows environment. Testing on Linux did also appear to show
638        some benefit (and it is clearly not harmful). Also fixed the definition of
639        Xop which should be unsigned.
641    5.  Related to (4), changing the definition of the intermediate variable cc
642        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
643        improvements.
645    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
646        unnecessary spaces.
648    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
649        and later.
651    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
653    9.  Optimizing fast_forward_start_bits in JIT.
655    10. Adding support for callouts in JIT, and fixing some issues revealed
656        during this work. Namely:
658        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
660        (b) Minimum length was not checked before the matching is started.
662    11. The value of capture_last that is passed to callouts was incorrect in some
663        cases when there was a capture on one path that was subsequently abandoned
664        after a backtrack. Also, the capture_last value is now reset after a
665        recursion, since all captures are also reset in this case.
667    12. The interpreter no longer returns the "too many substrings" error in the
668        case when an overflowing capture is in a branch that is subsequently
669        abandoned after a backtrack.
671    13. In the pathological case when an offset vector of size 2 is used, pcretest
672        now prints out the matched string after a yield of 0 or 1.
674    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
675        Only supported by the JIT compiler at the moment.
677    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
679    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
680        offset of the starting point of the matching process, provided the offsets
681        vector is large enough.
683    17. The \A escape now records a lookbehind value of 1, though its execution
684        does not actually inspect the previous character. This is to ensure that,
685        in partial multi-segment matching, at least one character from the old
686        segment is retained when a new segment is processed. Otherwise, if there
687        are no lookbehinds in the pattern, \A might match incorrectly at the start
688        of a new segment.
690    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
692    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
693        gives some modest performance improvement in 8-bit mode.
695    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
696        be expressed in certain programming languages using Universal Character
697        Names.
699    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
700        which points out that "non characters" are not "characters that may not
701        appear in Unicode strings" but rather "characters that are reserved for
702        internal use and have only local meaning".
704    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
705        there was a conditional group that depended on an assertion, if the
706        assertion was false, the callout that immediately followed the alternation
707        in the condition was skipped when pcre_exec() was used for matching.
709    23. Allow an explicit callout to be inserted before an assertion that is the
710        condition for a conditional group, for compatibility with automatic
711        callouts, which always insert a callout at this point.
713    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
714        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
716    25. (*PRUNE) is now supported by the JIT compiler.
718    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
720    27. Fix the case where there are two or more SKIPs with arguments that may be
721        ignored.
723    28. (*SKIP) is now supported by the JIT compiler.
725    29. (*THEN) is now supported by the JIT compiler.
727    30. Update RunTest with additional test selector options.
729    31. The way PCRE handles backtracking verbs has been changed in two ways.
731        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
732        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
733        backtracking. In some cases this makes it more Perl-compatible, but Perl's
734        rather obscure rules do not always do the same thing.
736        (2) Previously, backtracking verbs were confined within assertions. This is
737        no longer the case for positive assertions, except for (*ACCEPT). Again,
738        this sometimes improves Perl compatibility, and sometimes does not.
740    32. A number of tests that were in test 2 because Perl did things differently
741        have been moved to test 1, because either Perl or PCRE has changed, and
742        these tests are now compatible.
744    32. Backtracking control verbs are now handled in the same way in JIT and
745        interpreter.
747    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
748        contained a forward subroutine reference caused a compile error.
750    34. Auto-detect and optimize limited repetitions in JIT.
752    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
753        blocking (*UTF) etc.
755    36. In the interpreter, maximizing pattern repetitions for characters and
756        character types now use tail recursion, which reduces stack usage.
758    37. The value of the max lookbehind was not correctly preserved if a compiled
759        and saved regex was reloaded on a host of different endianness.
761    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
762        of the compiled pattern block, expand the flags field from 16 to 32 bits
763        because it was almost full.
765    39. Try madvise first before posix_madvise.
767    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
768        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
769        original change locked out all matches of empty strings. This has been
770        changed so that one match of an empty string per line is recognized.
771        Subsequent searches on the same line (for colouring or for --only-matching,
772        for example) do not recognize empty strings.
774    41. Applied a user patch to fix a number of spelling mistakes in comments.
776    42. Data lines longer than 65536 caused pcretest to crash.
778    43. Clarified the data type for length and startoffset arguments for pcre_exec
779        and pcre_dfa_exec in the function-specific man pages, where they were
780        explicitly stated to be in bytes, never having been updated. I also added
781        some clarification to the pcreapi man page.
783    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
784        a segmentation fault.
787    Version 8.32 30-November-2012
788    -----------------------------
790    1.  Improved JIT compiler optimizations for first character search and single
791        character iterators.
793    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
794        Patch by Daniel Richard G.
796    3.  Single character iterator optimizations in the JIT compiler.
798    4.  Improved JIT compiler optimizations for character ranges.
800    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
801        Reported by Giuseppe D'Angelo.
803    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
804        of a line, was being set incorrectly in cases where .* appeared inside
805        atomic brackets at the start of a pattern, or where there was a subsequent
806        *PRUNE or *SKIP.
808    7.  Improved instruction cache flush for POWER/PowerPC.
809        Patch by Daniel Richard G.
811    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
812        grep:
814        (a) There is now no limit to the number of patterns to be matched.
816        (b) An error is given if a pattern is too long.
818        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
819            are now supported.
821        (d) --exclude-from and --include-from (multiple use) have been added.
823        (e) Exclusions and inclusions now apply to all files and directories, not
824            just to those obtained from scanning a directory recursively.
826        (f) Multiple uses of -f and --file-list are now supported.
828        (g) In a Windows environment, the default for -d has been changed from
829            "read" (the GNU grep default) to "skip", because otherwise the presence
830            of a directory in the file list provokes an error.
832        (h) The documentation has been revised and clarified in places.
834    9.  Improve the matching speed of capturing brackets.
836    10. Changed the meaning of \X so that it now matches a Unicode extended
837        grapheme cluster.
839    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
840        out POSIX threads when JIT support is configured.
842    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
844    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
845        structure could go wrong in environments where size_t is not the same size
846        as int.
848    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
849        set.
851    15. The EBCDIC support had decayed; later updates to the code had included
852        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
853        general tidy up of EBCDIC-related issues, and the documentation was also
854        not quite right. There is now a test that can be run on ASCII systems to
855        check some of the EBCDIC-related things (but is it not a full test).
857    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
858        in a small tidy to the code.
860    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
862    18. If the --only-matching (-o) option in pcregrep is specified multiple
863        times, each one causes appropriate output. For example, -o1 -o2 outputs the
864        substrings matched by the 1st and 2nd capturing parentheses. A separating
865        string can be specified by --om-separator (default empty).
867    19. Improving the first n character searches.
869    20. Turn case lists for horizontal and vertical white space into macros so that
870        they are defined only once.
872    21. This set of changes together give more compatible Unicode case-folding
873        behaviour for characters that have more than one other case when UCP
874        support is available.
876        (a) The Unicode property table now has offsets into a new table of sets of
877            three or more characters that are case-equivalent. The MultiStage2.py
878            script that generates these tables (the pcre_ucd.c file) now scans
879            CaseFolding.txt instead of UnicodeData.txt for character case
880            information.
882        (b) The code for adding characters or ranges of characters to a character
883            class has been abstracted into a generalized function that also handles
884            case-independence. In UTF-mode with UCP support, this uses the new data
885            to handle characters with more than one other case.
887        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
888            whose other case is greater than 256 are now correctly matched
889            caselessly. Previously, the high codepoint matched the low one, but not
890            vice versa.
892        (d) The processing of \h, \H, \v, and \ in character classes now makes use
893            of the new class addition function, using character lists defined as
894            macros alongside the case definitions of 20 above.
896        (e) Caseless back references now work with characters that have more than
897            one other case.
899        (f) General caseless matching of characters with more than one other case
900            is supported.
902    22. Unicode character properties were updated from Unicode 6.2.0
904    23. Improved CMake support under Windows. Patch by Daniel Richard G.
906    24. Add support for 32-bit character strings, and UTF-32
908    25. Major JIT compiler update (code refactoring and bugfixing).
909        Experimental Sparc 32 support is added.
911    26. Applied a modified version of Daniel Richard G's patch to create
912        pcre.h.generic and config.h.generic by "make" instead of in the
913        PrepareRelease script.
915    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
916        pcre_compile.c when checking for a zero character.
918    28. Introducing a native interface for JIT. Through this interface, the compiled
919        machine code can be directly executed. The purpose of this interface is to
920        provide fast pattern matching, so several sanity checks are not performed.
921        However, feature tests are still performed. The new interface provides
922        1.4x speedup compared to the old one.
924    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
925        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
926        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
928    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
929        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
930        the "old" RFC 2279). Instead, it ended up passing a negative length to
931        pcre_exec().
933    31. Add support for GCC's visibility feature to hide internal functions.
935    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
936        "unknown -C option" after outputting 0 or 1.
938    33. There is now support for generating a code coverage report for the test
939        suite in environments where gcc is the compiler and lcov is installed. This
940        is mainly for the benefit of the developers.
942    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
943        unaddressable using valgrind annotations, allowing valgrind to detect
944        invalid memory accesses. This is mainly for the benefit of the developers.
946    25. (*UTF) can now be used to start a pattern in any of the three libraries.
948    26. Give configure error if --enable-cpp but no C++ compiler found.
951    Version 8.31 06-July-2012
952    -------------------------
954    1.  Fixing a wrong JIT test case and some compiler warnings.
956    2.  Removed a bashism from the RunTest script.
958    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
959        to unsigned type, result still unsigned" that was given by an MS compiler
960        on encountering the code "-sizeof(xxx)".
962    4.  Partial matching support is added to the JIT compiler.
964    5.  Fixed several bugs concerned with partial matching of items that consist
965        of more than one character:
967        (a) /^(..)\1/ did not partially match "aba" because checking references was
968            done on an "all or nothing" basis. This also applied to repeated
969            references.
971        (b) \R did not give a hard partial match if \r was found at the end of the
972            subject.
974        (c) \X did not give a hard partial match after matching one or more
975            characters at the end of the subject.
977        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
978            a partial match for the string "\r".
980        (e) When newline was set to CRLF, the metacharacter "." did not recognize
981            a partial match for a CR character at the end of the subject string.
983    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
984        running pcretest, the text "(JIT)" added to the output whenever JIT is
985        actually used to run the match.
987    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
988        or /S+[+] with a digit between 1 and 7.
990    8.  OP_NOT now supports any UTF character not just single-byte ones.
992    9.  (*MARK) control verb is now supported by the JIT compiler.
994    10. The command "./RunTest list" lists the available tests without actually
995        running any of them. (Because I keep forgetting what they all are.)
999    12. Applied a (slightly modified) user-supplied patch that improves performance
1000        when the heap is used for recursion (compiled with --disable-stack-for-
1001        recursion). Instead of malloc and free for each heap frame each time a
1002        logical recursion happens, frames are retained on a chain and re-used where
1003        possible. This sometimes gives as much as 30% improvement.
1005    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
1006        call.
1008    14. As documented, (*COMMIT) is now confined to within a positive assertion.
1010    15. It is now possible to link pcretest with libedit as an alternative to
1011        libreadline.
1013    16. (*COMMIT) control verb is now supported by the JIT compiler.
1015    17. The Unicode data tables have been updated to Unicode 6.1.0.
1017    18. Added --file-list option to pcregrep.
1019    19. Added binary file support to pcregrep, including the -a, --binary-files,
1020        -I, and --text options.
1022    20. The madvise function is renamed for posix_madvise for QNX compatibility
1023        reasons. Fixed by Giuseppe D'Angelo.
1025    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
1027    22. Changed the option for creating symbolic links for 16-bit man pages from
1028        -s to -sf so that re-installing does not cause issues.
1030    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
1032    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
1033        matches in certain environments (the workspace was not being correctly
1034        retained). Also added to pcre_dfa_exec() a simple plausibility check on
1035        some of the workspace data at the beginning of a restart.
1037    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
1038        was not doing so when it should - probably a typo introduced by SVN 528
1039        (change 8.10/14).
1041    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
1042        \w+ when the character tables indicated that \x{c4} was a word character.
1043        There were several related cases, all because the tests for doing a table
1044        lookup were testing for characters less than 127 instead of 255.
1046    27. If a pattern contains capturing parentheses that are not used in a match,
1047        their slots in the ovector are set to -1. For those that are higher than
1048        any matched groups, this happens at the end of processing. In the case when
1049        there were back references that the ovector was too small to contain
1050        (causing temporary malloc'd memory to be used during matching), and the
1051        highest capturing number was not used, memory off the end of the ovector
1052        was incorrectly being set to -1. (It was using the size of the temporary
1053        memory instead of the true size.)
1055    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
1056        ovector size, it uses memory at the end of the block that it has got.
1058    29. Check for an overlong MARK name and give an error at compile time. The
1059        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
1061    30. JIT compiler update.
1063    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
1064        Rill for the patch.
1066    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
1068    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
1070    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
1071        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
1072        was enabled.
1074    35. Improve JIT code generation for greedy plus quantifier.
1076    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
1077        1 to "aa" instead of to an empty string. The bug affected repeated groups
1078        that could potentially match an empty string.
1080    37. Optimizing single character iterators in JIT.
1082    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
1083        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
1084        codepoints that are too big for the mode are faulted, and in a UTF mode,
1085        disallowed codepoints are also faulted.
1087    39. If PCRE was compiled with UTF support, in three places in the DFA
1088        matcher there was code that should only have been obeyed in UTF mode, but
1089        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
1090        processing when bytes with values greater than 127 were present. In 16-bit
1091        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
1092        both cases the values are those that cannot be the first data item in a UTF
1093        character. The three items that might have provoked this were recursions,
1094        possessively repeated groups, and atomic groups.
1096    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
1097        and pcregrep, because some OS require shared objects to be explicitly
1098        passed to ld, causing the link step to fail if they are not.
1100    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
1101        mode, patterns that started with \h* or \R* might be incorrectly matched.
1104    Version 8.30 04-February-2012
1105    -----------------------------
1107    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1108        name is defined in ctype.h.
1110    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1111        only in quite long subpatterns.
1113    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1114        since it was replaced by pcre_fullinfo() in February 2000.
1116    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1117        match a (*MARK), and the match failed at the start of the subject, a
1118        reference to memory before the start of the subject could occur. This bug
1119        was introduced by fix 17 of release 8.21.
1121    5.  A reference to an unset group with zero minimum repetition was giving
1122        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1123        /(another)?(\1?)test/ matched against "hello world test". This bug was
1124        introduced in release 8.13.
1126    6.  Add support for 16-bit character strings (a large amount of work involving
1127        many changes and refactorings).
1129    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1130        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1131        from a file.
1133    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1134        rounding is not applied in this particular case).
1136    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1137        if they appear, or are escaped, in patterns.
1139    10. Get rid of a number of -Wunused-but-set-variable warnings.
1141    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1142        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1143        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1144        also returns the mark "x". This bug applied to capturing parentheses,
1145        non-capturing parentheses, and atomic parentheses. It also applied to some
1146        assertions.
1148    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1149        information out of configure.ac instead of relying on pcre.h.generic, which
1150        is not stored in the repository.
1152    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1153        -lreadline.
1155    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1157    15. Applied Graycode's patch to put the top-level frame on the stack rather
1158        than the heap when not using the stack for recursion. This gives a
1159        performance improvement in many cases when recursion is not deep.
1161    16. Experimental code added to "pcretest -C" to output the stack frame size.
1164    Version 8.21 12-Dec-2011
1165    ------------------------
1167    1.  Updating the JIT compiler.
1169    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1170        are added as well.
1172    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1173        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1174        calling _pcre_jit_exec. Some extra comments are added.
1176    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1177        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1178        was introduced by change 18 for 8.20.
1180    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1181        ECMA-262 standard.
1183    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1184        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1185        This bug was probably introduced by change 9 of 8.13.
1187    7.  While fixing 6 above, I noticed that a number of other items were being
1188        incorrectly rejected as "not fixed length". This arose partly because newer
1189        opcodes had not been added to the fixed-length checking code. I have (a)
1190        corrected the bug and added tests for these items, and (b) arranged for an
1191        error to occur if an unknown opcode is encountered while checking for fixed
1192        length instead of just assuming "not fixed length". The items that were
1193        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1194        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1195        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1197    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1198        being incorrectly compiled and would have given unpredicatble results.
1200    9.  A possessively repeated subpattern with minimum repeat count greater than
1201        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1202        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1203        the first (A) could occur when it should not.
1205    10. Add a cast and remove a redundant test from the code.
1207    11. JIT should use pcre_malloc/pcre_free for allocation.
1209    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1210        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1211        is anything other than /usr, -L is still shown).
1213    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1215    14. Perl does not support \N without a following name in a [] class; PCRE now
1216        also gives an error.
1218    15. If a forward reference was repeated with an upper limit of around 2000,
1219        it caused the error "internal error: overran compiling workspace". The
1220        maximum number of forward references (including repeats) was limited by the
1221        internal workspace, and dependent on the LINK_SIZE. The code has been
1222        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1223        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1224        of around 200,000 forward references. While doing this, I also speeded up
1225        the filling in of repeated forward references.
1227    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1228        incorrectly expecting the subject to contain another "a" after the start.
1230    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1231        in the match, the SKIP should be ignored. This was not happening; instead
1232        the SKIP was being treated as NOMATCH. For patterns such as
1233        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1234        tested.
1236    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1237        now much more compatible with Perl, in particular in cases where the result
1238        is a non-match for a non-anchored pattern. For example, if
1239        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1240        "m", where previously it did not return a name. A side effect of this
1241        change is that for partial matches, the last encountered mark name is
1242        returned, as for non matches. A number of tests that were previously not
1243        Perl-compatible have been moved into the Perl-compatible test files. The
1244        refactoring has had the pleasing side effect of removing one argument from
1245        the match() function, thus reducing its stack requirements.
1247    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1248        subsequent uses of /S (without +) incorrectly behaved like /S+.
1250    21. Retrieve executable code size support for the JIT compiler and fixing
1251        some warnings.
1253    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1254        not work when the shorter character appeared right at the end of the
1255        subject string.
1257    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1258        systems.
1260    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1261        output it when the /M option is used in pcretest.
1263    25. The CheckMan script was not being included in the distribution. Also, added
1264        an explicit "perl" to run Perl scripts from the PrepareRelease script
1265        because this is reportedly needed in Windows.
1267    26. If study data was being save in a file and studying had not found a set of
1268        "starts with" bytes for the pattern, the data written to the file (though
1269        never used) was taken from uninitialized memory and so caused valgrind to
1270        complain.
1272    27. Updated RunTest.bat as provided by Sheri Pierce.
1274    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1276    29. Computation of memory usage for the table of capturing group names was
1277        giving an unnecessarily large value.
1280    Version 8.20 21-Oct-2011
1281    ------------------------
1283    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1284        a POSIX class. After further experiments with Perl, which convinced me that
1285        Perl has bugs and confusions, a closing square bracket is no longer allowed
1286        in a POSIX name. This bug also affected patterns with classes that started
1287        with full stops.
1289    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1290        captured substring, but while checking the failing first alternative,
1291        substring 1 is temporarily captured. If the output vector supplied to
1292        pcre_exec() was not big enough for this capture, the yield of the function
1293        was still zero ("insufficient space for captured substrings"). This cannot
1294        be totally fixed without adding another stack variable, which seems a lot
1295        of expense for a edge case. However, I have improved the situation in cases
1296        such as /(a)(b)x|abc/ matched against "abc", where the return code
1297        indicates that fewer than the maximum number of slots in the ovector have
1298        been set.
1300    3.  Related to (2) above: when there are more back references in a pattern than
1301        slots in the output vector, pcre_exec() uses temporary memory during
1302        matching, and copies in the captures as far as possible afterwards. It was
1303        using the entire output vector, but this conflicts with the specification
1304        that only 2/3 is used for passing back captured substrings. Now it uses
1305        only the first 2/3, for compatibility. This is, of course, another edge
1306        case.
1308    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1309        main code base, and can be used by building with --enable-jit. When this is
1310        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1311        runtime --no-jit option is given.
1313    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1314        ovector, the return from the function was zero, implying that there were
1315        other matches that did not fit. The correct "exactly full" value is now
1316        returned.
1318    6.  If a subpattern that was called recursively or as a subroutine contained
1319        (*PRUNE) or any other control that caused it to give a non-standard return,
1320        invalid errors such as "Error -26 (nested recursion at the same subject
1321        position)" or even infinite loops could occur.
1323    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1324        computing the minimum length on reaching *ACCEPT, and so ended up with the
1325        wrong value of 1 rather than 0. Further investigation indicates that
1326        computing a minimum subject length in the presence of *ACCEPT is difficult
1327        (think back references, subroutine calls), and so I have changed the code
1328        so that no minimum is registered for a pattern that contains *ACCEPT.
1330    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1331        it was not handled as intended. [But see 16 below.]
1333    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1334        Sheri Pierce.
1336    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1337        the first byte in a match must be "a".
1339    11. Change 17 for 8.13 increased the recursion depth for patterns like
1340        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1341        pattern contains any instances of (*THEN). If it does not, the old
1342        optimizations are restored. It would be nice to do this on a per-group
1343        basis, but at the moment that is not feasible.
1345    12. In some environments, the output of pcretest -C is CRLF terminated. This
1346        broke RunTest's code that checks for the link size. A single white space
1347        character after the value is now allowed for.
1349    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1350        For "fr", it uses the Windows-specific input and output files.
1352    14. If (*THEN) appeared in a group that was called recursively or as a
1353        subroutine, it did not work as intended. [But see next item.]
1355    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1356        pattern fragments (but not containing any | characters). If A and B are
1357        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1358        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1359        D. In other words, Perl considers parentheses that do not contain any |
1360        characters to be part of a surrounding alternative, whereas PCRE was
1361        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1362        differently. PCRE now behaves in the same way as Perl, except in the case
1363        of subroutine/recursion calls such as (?1) which have in any case always
1364        been different (but PCRE had them first :-).
1366    16. Related to 15 above: Perl does not treat the | in a conditional group as
1367        creating alternatives. Such a group is treated in the same way as an
1368        ordinary group without any | characters when processing (*THEN). PCRE has
1369        been changed to match Perl's behaviour.
1371    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1372        RunGrepTest script failed.
1374    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1375        inevitable for groups that contain captures, but it can lead to a lot of
1376        stack use in large patterns. The old behaviour has been restored for atomic
1377        groups that do not contain any capturing parentheses.
1379    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1380        suppress the check for a minimum subject length at run time. (If it was
1381        given to pcre_exec() or pcre_dfa_exec() it did work.)
1383    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1384        fail to work when decoding hex characters in data strings in EBCDIC
1385        environments.
1387    21. It appears that in at least one Mac OS environment, the isxdigit() function
1388        is implemented as a macro that evaluates to its argument more than once,
1389        contravening the C 90 Standard (I haven't checked a later standard). There
1390        was an instance in pcretest which caused it to go wrong when processing
1391        \x{...} escapes in subject strings. The has been rewritten to avoid using
1392        things like p++ in the argument of isxdigit().
1395    Version 8.13 16-Aug-2011
1396    ------------------------
1398    1.  The Unicode data tables have been updated to Unicode 6.0.0.
1400    2.  Two minor typos in pcre_internal.h have been fixed.
1402    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
1403        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
1404        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
1406    4.  There were a number of related bugs in the code for matching backrefences
1407        caselessly in UTF-8 mode when codes for the characters concerned were
1408        different numbers of bytes. For example, U+023A and U+2C65 are an upper
1409        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
1410        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
1411        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
1412        2-byte code at the end of the subject (it thought there wasn't enough data
1413        left).
1415    5.  Comprehensive information about what went wrong is now returned by
1416        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
1417        as the output vector has at least 2 elements. The offset of the start of
1418        the failing character and a reason code are placed in the vector.
1420    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
1421        now returned is for the first byte of the failing character, instead of the
1422        last byte inspected. This is an incompatible change, but I hope it is small
1423        enough not to be a problem. It makes the returned offset consistent with
1424        pcre_exec() and pcre_dfa_exec().
1426    7.  pcretest now gives a text phrase as well as the error number when
1427        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
1428        failure, the offset and reason code are output.
1430    8.  When \R was used with a maximizing quantifier it failed to skip backwards
1431        over a \r\n pair if the subsequent match failed. Instead, it just skipped
1432        back over a single character (\n). This seems wrong (because it treated the
1433        two characters as a single entity when going forwards), conflicts with the
1434        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
1435        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
1436        has been changed.
1438    9.  Some internal refactoring has changed the processing so that the handling
1439        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
1440        time (the PCRE_DOTALL option was changed this way some time ago: version
1441        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
1442        which was always a bit of a fudge. It also means that there is one less
1443        argument for the match() function, which reduces its stack requirements
1444        slightly. This change also fixes an incompatibility with Perl: the pattern
1445        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
1447    10. More internal refactoring has drastically reduced the number of recursive
1448        calls to match() for possessively repeated groups such as (abc)++ when
1449        using pcre_exec().
1451    11. While implementing 10, a number of bugs in the handling of groups were
1452        discovered and fixed:
1454        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
1455        (a|)*(?1) gave a compile-time internal error.
1456        ((a|)+)+  did not notice that the outer group could match an empty string.
1457        (^a|^)+   was not marked as anchored.
1458        (.*a|.*)+ was not marked as matching at start or after a newline.
1460    12. Yet more internal refactoring has removed another argument from the match()
1461        function. Special calls to this function are now indicated by setting a
1462        value in a variable in the "match data" data block.
1464    13. Be more explicit in pcre_study() instead of relying on "default" for
1465        opcodes that mean there is no starting character; this means that when new
1466        ones are added and accidentally left out of pcre_study(), testing should
1467        pick them up.
1469    14. The -s option of pcretest has been documented for ages as being an old
1470        synonym of -m (show memory usage). I have changed it to mean "force study
1471        for every regex", that is, assume /S for every regex. This is similar to -i
1472        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
1473        using it. It makes it easier to run collections of tests with and without
1474        study enabled, and thereby test pcre_study() more easily. All the standard
1475        tests are now run with and without -s (but some patterns can be marked as
1476        "never study" - see 20 below).
1478    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
1479        restoration of the capturing data to the outer values was not happening
1480        correctly.
1482    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
1483        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
1484        pattern had matched an empty string, and so incorrectly returned a no
1485        match.
1487    17. There was optimizing code for the last branch of non-capturing parentheses,
1488        and also for the obeyed branch of a conditional subexpression, which used
1489        tail recursion to cut down on stack usage. Unfortunately, now that there is
1490        the possibility of (*THEN) occurring in these branches, tail recursion is
1491        no longer possible because the return has to be checked for (*THEN). These
1492        two optimizations have therefore been removed. [But see 8.20/11 above.]
1494    18. If a pattern containing \R was studied, it was assumed that \R always
1495        matched two bytes, thus causing the minimum subject length to be
1496        incorrectly computed because \R can also match just one byte.
1498    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
1499        was incorrectly computed.
1501    20. If /S is present twice on a test pattern in pcretest input, it now
1502        *disables* studying, thereby overriding the use of -s on the command line
1503        (see 14 above). This is necessary for one or two tests to keep the output
1504        identical in both cases.
1506    21. When (*ACCEPT) was used in an assertion that matched an empty string and
1507        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
1509    22. When an atomic group that contained a capturing parenthesis was
1510        successfully matched, but the branch in which it appeared failed, the
1511        capturing was not being forgotten if a higher numbered group was later
1512        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
1513        group 1 to "a", when in fact it should be unset. This applied to multi-
1514        branched capturing and non-capturing groups, repeated or not, and also to
1515        positive assertions (capturing in negative assertions does not happen
1516        in PCRE) and also to nested atomic groups.
1518    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
1519        subject after a captured substring, to make it easier to tell which of a
1520        number of identical substrings has been captured.
1522    24. The way atomic groups are processed by pcre_exec() has been changed so that
1523        if they are repeated, backtracking one repetition now resets captured
1524        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
1525        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
1526        "aaa". Previously, it would have been "a". As part of this code
1527        refactoring, the way recursive calls are handled has also been changed.
1529    25. If an assertion condition captured any substrings, they were not passed
1530        back unless some other capturing happened later. For example, if
1531        (?(?=(a))a) was matched against "a", no capturing was returned.
1533    26. When studying a pattern that contained subroutine calls or assertions,
1534        the code for finding the minimum length of a possible match was handling
1535        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
1536        group 1 called group 2 while simultaneously a separate group 2 called group
1537        1). A stack overflow occurred in this case. I have fixed this by limiting
1538        the recursion depth to 10.
1540    27. Updated RunTest.bat in the distribution to the version supplied by Tom
1541        Fortmann. This supports explicit test numbers on the command line, and has
1542        argument validation and error reporting.
1544    28. An instance of \X with an unlimited repeat could fail if at any point the
1545        first character it looked at was a mark character.
1547    29. Some minor code refactoring concerning Unicode properties and scripts
1548        should reduce the stack requirement of match() slightly.
1550    30. Added the '=' option to pcretest to check the setting of unused capturing
1551        slots at the end of the pattern, which are documented as being -1, but are
1552        not included in the return count.
1554    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
1555        compiled something random. Now it gives a compile-time error (as does
1556        Perl).
1558    32. A *MARK encountered during the processing of a positive assertion is now
1559        recorded and passed back (compatible with Perl).
1561    33. If --only-matching or --colour was set on a pcregrep call whose pattern
1562        had alternative anchored branches, the search for a second match in a line
1563        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
1564        matched the line "0102" twice. The same bug affected patterns that started
1565        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
1566        twice.
1568    34. Previously, PCRE did not allow quantification of assertions. However, Perl
1569        does, and because of capturing effects, quantifying parenthesized
1570        assertions may at times be useful. Quantifiers are now allowed for
1571        parenthesized assertions.
1573    35. A minor code tidy in pcre_compile() when checking options for \R usage.
1575    36. \g was being checked for fancy things in a character class, when it should
1576        just be a literal "g".
1578    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
1579        appearance of a nested POSIX class supersedes an apparent external class.
1580        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1581        unescaped square brackets may also appear as part of class names. For
1582        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1583        more like Perl. (But see 8.20/1 above.)
1585    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1586        was because it thought it was \N{name}, which is not supported).
1588    39. Add minix to OS list not supporting the -S option in pcretest.
1590    40. PCRE tries to detect cases of infinite recursion at compile time, but it
1591        cannot analyze patterns in sufficient detail to catch mutual recursions
1592        such as ((?1))((?2)). There is now a runtime test that gives an error if a
1593        subgroup is called recursively as a subpattern for a second time at the
1594        same position in the subject string. In previous releases this might have
1595        been caught by the recursion limit, or it might have run out of stack.
1597    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
1598        happen only once. PCRE was, however incorrectly giving a compile time error
1599        "recursive call could loop indefinitely" because it cannot analyze the
1600        pattern in sufficient detail. The compile time test no longer happens when
1601        PCRE is compiling a conditional subpattern, but actual runaway loops are
1602        now caught at runtime (see 40 above).
1604    42. It seems that Perl allows any characters other than a closing parenthesis
1605        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
1606        has been changed to be the same.
1608    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
1609        as not to get warnings when autogen.sh is called. Also changed
1610        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
1612    44. To help people who use pcregrep to scan files containing exceedingly long
1613        lines, the following changes have been made:
1615        (a) The default value of the buffer size parameter has been increased from
1616            8K to 20K. (The actual buffer used is three times this size.)
1618        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1619            PCRE is built.
1621        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
1622            to be set at run time.
1624        (d) Numerical values in pcregrep options can be followed by K or M, for
1625            example --buffer-size=50K.
1627        (e) If a line being scanned overflows pcregrep's buffer, an error is now
1628            given and the return code is set to 2.
1630    45. Add a pointer to the latest mark to the callout data block.
1632    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
1633        partial match of an empty string instead of no match. This was specific to
1634        the use of ".".
1636    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1637        complete match instead of a partial match. This bug was dependent on both
1638        the PCRE_UTF8 and PCRE_DOTALL options being set.
1640    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1641        starting byte set, because \b was not being ignored.
1644    Version 8.12 15-Jan-2011
1645    ------------------------
1647    1.  Fixed some typos in the markup of the man pages, and wrote a script that
1648        checks for such things as part of the documentation building process.
1650    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
1651        --match-limit and --recursion-limit options (added for 8.11). In
1652        particular, this made one of the standard tests fail. (The integer value
1653        went into the wrong half of a long int.)
1655    3.  If the --colour option was given to pcregrep with -v (invert match), it
1656        did strange things, either producing crazy output, or crashing. It should,
1657        of course, ignore a request for colour when reporting lines that do not
1658        match.
1660    4.  Another pcregrep bug caused similar problems if --colour was specified with
1661        -M (multiline) and the pattern match finished with a line ending.
1663    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
1664        matched in multiline mode, the following line was shown as part of the
1665        match. This seems wrong, so I have changed it.
1667    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
1668        the check for further matches in the same line (so they could be coloured)
1669        to overrun the end of the current line. If another match was found, it was
1670        incorrectly shown (and then shown again when found in the next line).
1672    7.  If pcregrep was compiled under Windows, there was a reference to the
1673        function pcregrep_exit() before it was defined. I am assuming this was
1674        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
1675        reported by a user. I've moved the definition above the reference.
1678    Version 8.11 10-Dec-2010
1679    ------------------------
1681    1.  (*THEN) was not working properly if there were untried alternatives prior
1682        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
1683        backtracked to try for "b" instead of moving to the next alternative branch
1684        at the same level (in this case, to look for "c"). The Perl documentation
1685        is clear that when (*THEN) is backtracked onto, it goes to the "next
1686        alternative in the innermost enclosing group".
1688    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
1689        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
1690        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
1691        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
1692        (*THEN).
1694    3.  If \s appeared in a character class, it removed the VT character from
1695        the class, even if it had been included by some previous item, for example
1696        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1697        of \s, but is part of the POSIX "space" class.)
1699    4.  A partial match never returns an empty string (because you can always
1700        match an empty string at the end of the subject); however the checking for
1701        an empty string was starting at the "start of match" point. This has been
1702        changed to the "earliest inspected character" point, because the returned
1703        data for a partial match starts at this character. This means that, for
1704        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1705        (previously it gave "no match").
1707    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1708        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1709        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1710        has an implication that the given string is incomplete (because a partial
1711        match is preferred over a full match). For this reason, these items now
1712        give a partial match in this situation. [Aside: previously, the one case
1713        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1714        match rather than a full match, which was wrong by the old rules, but is
1715        now correct.]
1717    6.  There was a bug in the handling of #-introduced comments, recognized when
1718        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1719        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1720        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1721        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1722        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1723        places in pcre_compile().
1725    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1726        comments when looking ahead for named forward references to subpatterns,
1727        the only newline sequence it recognized was NL. It now handles newlines
1728        according to the set newline convention.
1730    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1731        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1732        cater for a lack of strerror(). These oversights have been fixed.
1734    9.  Added --match-limit and --recursion-limit to pcregrep.
1736    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1738    11. When the -o option was used, pcregrep was setting a return code of 1, even
1739        when matches were found, and --line-buffered was not being honoured.
1741    12. Added an optional parentheses number to the -o and --only-matching options
1742        of pcregrep.
1744    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1745        can match an empty string. The code to do it in pcretest and pcredemo
1746        needed fixing:
1748        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1749            only one byte after an empty string match just before CRLF (this case
1750            just got forgotten; "any" and "anycrlf" were OK).
1752        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1753            mode when an empty string match preceded an ASCII character followed by
1754            a non-ASCII character. (The code for advancing by one character rather
1755            than one byte was nonsense.)
1757        (c) The pcredemo.c sample program did not have any code at all to handle
1758            the cases when CRLF is a valid newline sequence.
1760    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1761        as a starting offset was within the subject string. There is now a new
1762        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1763        negative or greater than the length of the string. In order to test this,
1764        pcretest is extended to allow the setting of negative starting offsets.
1766    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1767        starting offset points to the beginning of a UTF-8 character was
1768        unnecessarily clumsy. I tidied it up.
1770    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1771        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1773    17. Nobody had reported that the --include_dir option, which was added in
1774        release 7.7 should have been called --include-dir (hyphen, not underscore)
1775        for compatibility with GNU grep. I have changed it to --include-dir, but
1776        left --include_dir as an undocumented synonym, and the same for
1777        --exclude-dir, though that is not available in GNU grep, at least as of
1778        release 2.5.4.
1780    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1781        characters from a string of bytes) have been redefined so as not to use
1782        loops, in order to improve performance in some environments. At the same
1783        time, I abstracted some of the common code into auxiliary macros to save
1784        repetition (this should not affect the compiled code).
1786    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1787        compile-time error is now given if \c is not followed by an ASCII
1788        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1789        different, and any byte value is allowed.)
1791    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1792        START_OPTIMIZE option, which is now allowed at compile time - but just
1793        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1794        to pcregrep and other applications that have no direct access to PCRE
1795        options. The new /Y option in pcretest sets this option when calling
1796        pcre_compile().
1798    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1799        back references. Groups containing recursive back references were forced to
1800        be atomic by that change, but in the case of named groups, the amount of
1801        memory required was incorrectly computed, leading to "Failed: internal
1802        error: code overflow". This has been fixed.
1804    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1805        pcretest.c, to avoid build problems in some Borland environments.
1808    Version 8.10 25-Jun-2010
1809    ------------------------
1811    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1812        THEN.
1814    2.  (*ACCEPT) was not working when inside an atomic group.
1816    3.  Inside a character class, \B is treated as a literal by default, but
1817        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1818        causes the error). The code is unchanged, but I tidied the documentation.
1820    4.  Inside a character class, PCRE always treated \R and \X as literals,
1821        whereas Perl faults them if its -w option is set. I have changed PCRE so
1822        that it faults them when PCRE_EXTRA is set.
1824    5.  Added support for \N, which always matches any character other than
1825        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1827    6.  When compiling pcregrep with newer versions of gcc which may have
1828        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1829        declared with attribute warn_unused_result" were given. Just casting the
1830        result to (void) does not stop the warnings; a more elaborate fudge is
1831        needed. I've used a macro to implement this.
1833    7.  Minor change to pcretest.c to avoid a compiler warning.
1835    8.  Added four artifical Unicode properties to help with an option to make
1836        \s etc use properties (see next item). The new properties are: Xan
1837        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1839    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1840        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1841        this option. Modified pcretest to add /W to test this facility. Added
1842        REG_UCP to make it available via the POSIX interface.
1844    10. Added --line-buffered to pcregrep.
1846    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1847        studied, and the match started with a letter with a code point greater than
1848        127 whose first byte was different to the first byte of the other case of
1849        the letter, the other case of this starting letter was not recognized
1850        (#976).
1852    12. If a pattern that was studied started with a repeated Unicode property
1853        test, for example, \p{Nd}+, there was the theoretical possibility of
1854        setting up an incorrect bitmap of starting bytes, but fortunately it could
1855        not have actually happened in practice until change 8 above was made (it
1856        added property types that matched character-matching opcodes).
1858    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1859        possible starting bytes for non-anchored patterns.
1861    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1862        \R, and also a number of cases that involve Unicode properties, both
1863        explicit and implicit when PCRE_UCP is set.
1865    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1866        input, it could crash or give wrong results if characters with values
1867        greater than 0xc0 were present in the subject string. (Detail: it assumed
1868        UTF-8 input when processing these items.)
1870    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1871        size_t is 64-bit (#991).
1873    17. Added a check for running out of memory when PCRE is compiled with
1874        --disable-stack-for-recursion (#990).
1876    18. If the last data line in a file for pcretest does not have a newline on
1877        the end, a newline was missing in the output.
1879    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1880        less than 128) in its various bitmaps. However, there is a facility for
1881        generating tables according to the current locale when PCRE is compiled. It
1882        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1883        characters, are recognized by isspace() and therefore were getting set in
1884        these tables, and indeed these tables seem to approximate to ISO 8859. This
1885        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1886        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1887        which of course cannot start UTF-8 characters. I have changed the code so
1888        that only real ASCII characters (less than 128) and the correct starting
1889        bytes for UTF-8 encodings are set for characters greater than 127 when in
1890        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1891        altogether.)
1893    20. Added the /T option to pcretest so as to be able to run tests with non-
1894        standard character tables, thus making it possible to include the tests
1895        used for 19 above in the standard set of tests.
1897    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1898        reference to a subpattern the other side of a comment that contains an
1899        opening parenthesis caused either an internal compiling error, or a
1900        reference to the wrong subpattern.
1903    Version 8.02 19-Mar-2010
1904  ------------------------  ------------------------
1906  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
1908  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1909      configured.      configured.
1911  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1912      original author of that file, following a query about its status.      original author of that file, following a query about its status.
1914  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1915      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1917  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1918      quantifier applied to a forward-referencing subroutine call, could compile      quantifier applied to a forward-referencing subroutine call, could compile
1919      incorrect code or give the error "internal error: previously-checked      incorrect code or give the error "internal error: previously-checked
1920      referenced subpattern not found".      referenced subpattern not found".
1922  6.  Both MS Visual Studio and Symbian OS have problems with initializing  6.  Both MS Visual Studio and Symbian OS have problems with initializing
1923      variables to point to external functions. For these systems, therefore,      variables to point to external functions. For these systems, therefore,
1924      pcre_malloc etc. are now initialized to local functions that call the      pcre_malloc etc. are now initialized to local functions that call the
1925      relevant global functions.      relevant global functions.
1927  7.  There were two entries missing in the vectors called coptable and poptable  7.  There were two entries missing in the vectors called coptable and poptable
1928      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1929      I've fixed the data, and added a kludgy way of testing at compile time that      I've fixed the data, and added a kludgy way of testing at compile time that
1930      the lengths are correct (equal to the number of opcodes).      the lengths are correct (equal to the number of opcodes).
1932  8.  Following on from 7, I added a similar kludge to check the length of the  8.  Following on from 7, I added a similar kludge to check the length of the
1933      eint vector in pcreposix.c.      eint vector in pcreposix.c.
1935  9.  Error texts for pcre_compile() are held as one long string to avoid too  9.  Error texts for pcre_compile() are held as one long string to avoid too
1936      much relocation at load time. To find a text, the string is searched,      much relocation at load time. To find a text, the string is searched,
1937      counting zeros. There was no check for running off the end of the string,      counting zeros. There was no check for running off the end of the string,
1938      which could happen if a new error number was added without updating the      which could happen if a new error number was added without updating the
1939      string.      string.
1941  10. \K gave a compile-time error if it appeared in a lookbehind assersion.  10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1943  11. \K was not working if it appeared in an atomic group or in a group that  11. \K was not working if it appeared in an atomic group or in a group that
1944      was called as a "subroutine", or in an assertion. Perl 5.11 documents that      was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1945      \K is "not well defined" if used in an assertion. PCRE now accepts it if      \K is "not well defined" if used in an assertion. PCRE now accepts it if
1946      the assertion is positive, but not if it is negative.      the assertion is positive, but not if it is negative.
1948  12. Change 11 fortuitously reduced the size of the stack frame used in the  12. Change 11 fortuitously reduced the size of the stack frame used in the
1949      "match()" function of pcre_exec.c by one pointer. Forthcoming      "match()" function of pcre_exec.c by one pointer. Forthcoming
1950      implementation of support for (*MARK) will need an extra pointer on the      implementation of support for (*MARK) will need an extra pointer on the
1951      stack; I have reserved it now, so that the stack frame size does not      stack; I have reserved it now, so that the stack frame size does not
1952      decrease.      decrease.
1954  13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other  13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1955      item in branch that calls a recursion is a subroutine call - as in the      item in branch that calls a recursion is a subroutine call - as in the
1956      second branch in the above example - was incorrectly given the compile-      second branch in the above example - was incorrectly given the compile-
1957      time error "recursive call could loop indefinitely" because pcre_compile()      time error "recursive call could loop indefinitely" because pcre_compile()
1958      was not correctly checking the subroutine for matching a non-empty string.      was not correctly checking the subroutine for matching a non-empty string.
1960  14. The checks for overrunning compiling workspace could trigger after an  14. The checks for overrunning compiling workspace could trigger after an
1961      overrun had occurred. This is a "should never occur" error, but it can be      overrun had occurred. This is a "should never occur" error, but it can be
1962      triggered by pathological patterns such as hundreds of nested parentheses.      triggered by pathological patterns such as hundreds of nested parentheses.
1963      The checks now trigger 100 bytes before the end of the workspace.      The checks now trigger 100 bytes before the end of the workspace.
1965    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1968  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
# Line 390  Version 7.9 11-Apr-09 Line 2291  Version 7.9 11-Apr-09
2291  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
2292      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
2293      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2294      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2295        8.33.]
2297  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
2298      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 633  Version 7.7 07-May-08 Line 2535  Version 7.7 07-May-08
2535      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2536      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2537      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2538      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2539      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2540      was subsequently set up correctly.)      was subsequently set up correctly.)

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