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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.13 02-Aug-2011  Note that the PCRE 8.xx series (PCRE1) is now in a bugfix-only state. All
5    development is happening in the PCRE2 10.xx series.
7    Version 8.38 xx-xxx-xxxx
8    ------------------------
10    1.  If a group that contained a recursive back reference also contained a
11        forward reference subroutine call followed by a non-forward-reference
12        subroutine call, for example /.((?2)(?R)\1)()/, pcre2_compile() failed to
13        compile correct code, leading to undefined behaviour or an internally
14        detected error. This bug was discovered by the LLVM fuzzer.
16    2.  Quantification of certain items (e.g. atomic back references) could cause
17        incorrect code to be compiled when recursive forward references were
18        involved. For example, in this pattern: /(?1)()((((((\1++))\x85)+)|))/.
19        This bug was discovered by the LLVM fuzzer.
21    3.  A repeated conditional group whose condition was a reference by name caused
22        a buffer overflow if there was more than one group with the given name.
23        This bug was discovered by the LLVM fuzzer.
25    4.  A recursive back reference by name within a group that had the same name as
26        another group caused a buffer overflow. For example:
27        /(?J)(?'d'(?'d'\g{d}))/. This bug was discovered by the LLVM fuzzer.
29    5.  A forward reference by name to a group whose number is the same as the
30        current group, for example in this pattern: /(?|(\k'Pm')|(?'Pm'))/, caused
31        a buffer overflow at compile time. This bug was discovered by the LLVM
32        fuzzer.
34    6.  A lookbehind assertion within a set of mutually recursive subpatterns could
35        provoke a buffer overflow. This bug was discovered by the LLVM fuzzer.
37    7.  Another buffer overflow bug involved duplicate named groups with a
38        reference between their definition, with a group that reset capture
39        numbers, for example: /(?J:(?|(?'R')(\k'R')|((?'R'))))/. This has been
40        fixed by always allowing for more memory, even if not needed. (A proper fix
41        is implemented in PCRE2, but it involves more refactoring.)
43    8.  There was no check for integer overflow in subroutine calls such as (?123).
45    9.  The table entry for \l in EBCDIC environments was incorrect, leading to its
46        being treated as a literal 'l' instead of causing an error.
48    10. There was a buffer overflow if pcre_exec() was called with an ovector of
49        size 1. This bug was found by american fuzzy lop.
51    11. If a non-capturing group containing a conditional group that could match
52        an empty string was repeated, it was not identified as matching an empty
53        string itself. For example: /^(?:(?(1)x|)+)+$()/.
55    12. In an EBCDIC environment, pcretest was mishandling the escape sequences
56        \a and \e in test subject lines.
58    13. In an EBCDIC environment, \a in a pattern was converted to the ASCII
59        instead of the EBCDIC value.
61    14. The handling of \c in an EBCDIC environment has been revised so that it is
62        now compatible with the specification in Perl's perlebcdic page.
64    15. The EBCDIC character 0x41 is a non-breaking space, equivalent to 0xa0 in
65        ASCII/Unicode. This has now been added to the list of characters that are
66        recognized as white space in EBCDIC.
68    16. When PCRE was compiled without UCP support, the use of \p and \P gave an
69        error (correctly) when used outside a class, but did not give an error
70        within a class.
72    17. \h within a class was incorrectly compiled in EBCDIC environments.
74    18. A pattern with an unmatched closing parenthesis that contained a backward
75        assertion which itself contained a forward reference caused buffer
76        overflow. And example pattern is: /(?=di(?<=(?1))|(?=(.))))/.
78    19. JIT should return with error when the compiled pattern requires more stack
79        space than the maximum.
81    20. A possessively repeated conditional group that could match an empty string,
82        for example, /(?(R))*+/, was incorrectly compiled.
84    21. Fix infinite recursion in the JIT compiler when certain patterns such as
85        /(?:|a|){100}x/ are analysed.
87    22. Some patterns with character classes involving [: and \\ were incorrectly
88        compiled and could cause reading from uninitialized memory or an incorrect
89        error diagnosis.
91    23. Pathological patterns containing many nested occurrences of [: caused
92        pcre_compile() to run for a very long time.
94    24. A conditional group with only one branch has an implicit empty alternative
95        branch and must therefore be treated as potentially matching an empty
96        string.
98    25. If (?R was followed by - or + incorrect behaviour happened instead of a
99        diagnostic.
101    26. Arrange to give up on finding the minimum matching length for overly
102        complex patterns.
104    27. Similar to (4) above: in a pattern with duplicated named groups and an
105        occurrence of (?| it is possible for an apparently non-recursive back
106        reference to become recursive if a later named group with the relevant
107        number is encountered. This could lead to a buffer overflow. Wen Guanxing
108        from Venustech ADLAB discovered this bug.
110    28. If pcregrep was given the -q option with -c or -l, or when handling a
111        binary file, it incorrectly wrote output to stdout.
113    29. The JIT compiler did not restore the control verb head in case of *THEN
114        control verbs. This issue was found by Karl Skomski with a custom LLVM
115        fuzzer.
117    30. Error messages for syntax errors following \g and \k were giving inaccurate
118        offsets in the pattern.
120    31. Added a check for integer overflow in conditions (?(<digits>) and
121        (?(R<digits>). This omission was discovered by Karl Skomski with the LLVM
122        fuzzer.
124    32. Handling recursive references such as (?2) when the reference is to a group
125        later in the pattern uses code that is very hacked about and error-prone.
126        It has been re-written for PCRE2. Here in PCRE1, a check has been added to
127        give an internal error if it is obvious that compiling has gone wrong.
130    Version 8.37 28-April-2015
131    --------------------------
133    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
134        for those parentheses to be closed with whatever has been captured so far.
135        However, it was failing to mark any other groups between the hightest
136        capture so far and the currrent group as "unset". Thus, the ovector for
137        those groups contained whatever was previously there. An example is the
138        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
140    2.  If an assertion condition was quantified with a minimum of zero (an odd
141        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
143    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
144        unrecognized modifier, a crash could occur.
146    4.  An attempt to do global matching in pcretest with a zero-length ovector
147        caused a crash.
149    5.  Fixed a memory leak during matching that could occur for a subpattern
150        subroutine call (recursive or otherwise) if the number of captured groups
151        that had to be saved was greater than ten.
153    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
154        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
155        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
157    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
158        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
160    8. When a pattern is compiled, it remembers the highest back reference so that
161       when matching, if the ovector is too small, extra memory can be obtained to
162       use instead. A conditional subpattern whose condition is a check on a
163       capture having happened, such as, for example in the pattern
164       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
165       setting the highest backreference number. This mattered only if pcre_exec()
166       was called with an ovector that was too small to hold the capture, and there
167       was no other kind of back reference (a situation which is probably quite
168       rare). The effect of the bug was that the condition was always treated as
169       FALSE when the capture could not be consulted, leading to a incorrect
170       behaviour by pcre_exec(). This bug has been fixed.
172    9. A reference to a duplicated named group (either a back reference or a test
173       for being set in a conditional) that occurred in a part of the pattern where
174       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
175       to be incorrectly calculated, leading to overwriting.
177    10. A mutually recursive set of back references such as (\2)(\1) caused a
178        segfault at study time (while trying to find the minimum matching length).
179        The infinite loop is now broken (with the minimum length unset, that is,
180        zero).
182    11. If an assertion that was used as a condition was quantified with a minimum
183        of zero, matching went wrong. In particular, if the whole group had
184        unlimited repetition and could match an empty string, a segfault was
185        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
186        assertions to be quantified, but not if they are being used as conditions,
187        so the above pattern is faulted by Perl. PCRE has now been changed so that
188        it also rejects such patterns.
190    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
191        failed to allow the zero-repeat case if pcre2_exec() was called with an
192        ovector too small to capture the group.
194    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
195        Red Hat Product Security:
197        (a) A crash if /K and /F were both set with the option to save the compiled
198        pattern.
200        (b) Another crash if the option to print captured substrings in a callout
201        was combined with setting a null ovector, for example \O\C+ as a subject
202        string.
204    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
205        forward reference repeated a large (but limited) number of times within a
206        repeated outer group that has a zero minimum quantifier, caused incorrect
207        code to be compiled, leading to the error "internal error:
208        previously-checked referenced subpattern not found" when an incorrect
209        memory address was read. This bug was reported as "heap overflow",
210        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
211        CVE-2015-2325.
213    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
214        call within a group that also contained a recursive back reference caused
215        incorrect code to be compiled. This bug was reported as "heap overflow",
216        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
217        number CVE-2015-2326.
219    24. Computing the size of the JIT read-only data in advance has been a source
220        of various issues, and new ones are still appear unfortunately. To fix
221        existing and future issues, size computation is eliminated from the code,
222        and replaced by on-demand memory allocation.
224    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
225        adjacent to the end of the range, and the range contained characters with
226        more than one other case, caused incorrect behaviour when compiled in UTF
227        mode. In that example, the range a-j was left out of the class.
229    26. Fix JIT compilation of conditional blocks, which assertion
230        is converted to (*FAIL). E.g: /(?(?!))/.
232    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
233        discovered by the LLVM fuzzer.
235    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
236        when this assertion was used as a condition, for example (?(?!)a|b). In
237        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
238        error about an unsupported item.
240    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
241        possessification code could take exponential time to complete. A recursion
242        depth limit of 1000 has been imposed to limit the resources used by this
243        optimization.
245    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
246        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
247        because \S ensures they are all in the class. The code for doing this was
248        interacting badly with the code for computing the amount of space needed to
249        compile the pattern, leading to a buffer overflow. This bug was discovered
250        by the LLVM fuzzer.
252    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
253        other kinds of group caused stack overflow at compile time. This bug was
254        discovered by the LLVM fuzzer.
256    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
257        between a subroutine call and its quantifier was incorrectly compiled,
258        leading to buffer overflow or other errors. This bug was discovered by the
259        LLVM fuzzer.
261    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
262        assertion after (?(. The code was failing to check the character after
263        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
264        was discovered by the LLVM fuzzer.
266    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
267        a fixed maximum following a group that contains a subroutine reference was
268        incorrectly compiled and could trigger buffer overflow. This bug was
269        discovered by the LLVM fuzzer.
271    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
272        caused a stack overflow instead of the diagnosis of a non-fixed length
273        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
275    36. The use of \K in a positive lookbehind assertion in a non-anchored pattern
276        (e.g. /(?<=\Ka)/) could make pcregrep loop.
278    37. There was a similar problem to 36 in pcretest for global matches.
280    38. If a greedy quantified \X was preceded by \C in UTF mode (e.g. \C\X*),
281        and a subsequent item in the pattern caused a non-match, backtracking over
282        the repeated \X did not stop, but carried on past the start of the subject,
283        causing reference to random memory and/or a segfault. There were also some
284        other cases where backtracking after \C could crash. This set of bugs was
285        discovered by the LLVM fuzzer.
287    39. The function for finding the minimum length of a matching string could take
288        a very long time if mutual recursion was present many times in a pattern,
289        for example, /((?2){73}(?2))((?1))/. A better mutual recursion detection
290        method has been implemented. This infelicity was discovered by the LLVM
291        fuzzer.
293    40. Static linking against the PCRE library using the pkg-config module was
294        failing on missing pthread symbols.
297    Version 8.36 26-September-2014
298    ------------------------------
300    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
301        -Wmissing-field-initializers and -Wunused-parameter.
303    2.  The tests for quantifiers being too big (greater than 65535) were being
304        applied after reading the number, and stupidly assuming that integer
305        overflow would give a negative number. The tests are now applied as the
306        numbers are read.
308    3.  Tidy code in pcre_exec.c where two branches that used to be different are
309        now the same.
311    4.  The JIT compiler did not generate match limit checks for certain
312        bracketed expressions with quantifiers. This may lead to exponential
313        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
314        issue should be resolved now.
316    5.  Fixed an issue, which occures when nested alternatives are optimized
317        with table jumps.
319    6.  Inserted two casts and changed some ints to size_t in the light of some
320        reported 64-bit compiler warnings (Bugzilla 1477).
322    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
323        an empty string, which sometimes were behaving incorrectly in the
324        interpreter (though correctly in the JIT matcher). This pcretest input is
325        an example:
327          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
330        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
331        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
332        for an empty string was breaking the inner loop and carrying on at a lower
333        level, when possessive repeated groups should always return to a higher
334        level as they have no backtrack points in them. The empty string test now
335        occurs at the outer level.
337    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
338        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
340    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
341        doesn't).
343    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
344        to hold a pattern to be incorrectly computed (too small) when there were
345        named back references to duplicated names. This could cause "internal
346        error: code overflow" or "double free or corruption" or other memory
347        handling errors.
349    11. When named subpatterns had the same prefixes, back references could be
350        confused. For example, in this pattern:
352          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
354        the reference to 'Name' was incorrectly treated as a reference to a
355        duplicate name.
357    12. A pattern such as /^s?c/mi8 where the optional character has more than
358        one "other case" was incorrectly compiled such that it would only try to
359        match starting at "c".
361    13. When a pattern starting with \s was studied, VT was not included in the
362        list of possible starting characters; this should have been part of the
363        8.34/18 patch.
365    14. If a character class started [\Qx]... where x is any character, the class
366        was incorrectly terminated at the ].
368    15. If a pattern that started with a caseless match for a character with more
369        than one "other case" was studied, PCRE did not set up the starting code
370        unit bit map for the list of possible characters. Now it does. This is an
371        optimization improvement, not a bug fix.
373    16. The Unicode data tables have been updated to Unicode 7.0.0.
375    17. Fixed a number of memory leaks in pcregrep.
377    18. Avoid a compiler warning (from some compilers) for a function call with
378        a cast that removes "const" from an lvalue by using an intermediate
379        variable (to which the compiler does not object).
381    19. Incorrect code was compiled if a group that contained an internal recursive
382        back reference was optional (had quantifier with a minimum of zero). This
383        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
384        caused segmentation faults because of stack overflows at compile time.
386    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
387        group that is quantified with an indefinite repeat, caused a compile-time
388        loop which used up all the system stack and provoked a segmentation fault.
389        This was not the same bug as 19 above.
391    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
392        Patch by Mike Frysinger.
395    Version 8.35 04-April-2014
396    --------------------------
398    1.  A new flag is set, when property checks are present in an XCLASS.
399        When this flag is not set, PCRE can perform certain optimizations
400        such as studying these XCLASS-es.
402    2.  The auto-possessification of character sets were improved: a normal
403        and an extended character set can be compared now. Furthermore
404        the JIT compiler optimizes more character set checks.
406    3.  Got rid of some compiler warnings for potentially uninitialized variables
407        that show up only when compiled with -O2.
409    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
410        of a match later then the end of the match. The pcretest program was not
411        handling the case sensibly - it was outputting from the start to the next
412        binary zero. It now reports this situation in a message, and outputs the
413        text from the end to the start.
415    5.  Fast forward search is improved in JIT. Instead of the first three
416        characters, any three characters with fixed position can be searched.
417        Search order: first, last, middle.
419    6.  Improve character range checks in JIT. Characters are read by an inprecise
420        function now, which returns with an unknown value if the character code is
421        above a certain threshold (e.g: 256). The only limitation is that the value
422        must be bigger than the threshold as well. This function is useful when
423        the characters above the threshold are handled in the same way.
425    7.  The macros whose names start with RAWUCHAR are placeholders for a future
426        mode in which only the bottom 21 bits of 32-bit data items are used. To
427        make this more memorable for those maintaining the code, the names have
428        been changed to start with UCHAR21, and an extensive comment has been added
429        to their definition.
431    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
432        to the export list in Makefile.am (they were accidentally omitted from the
433        8.34 tarball).
435    9.  The informational output from pcretest used the phrase "starting byte set"
436        which is inappropriate for the 16-bit and 32-bit libraries. As the output
437        for "first char" and "need char" really means "non-UTF-char", I've changed
438        "byte" to "char", and slightly reworded the output. The documentation about
439        these values has also been (I hope) clarified.
441    10. Another JIT related optimization: use table jumps for selecting the correct
442        backtracking path, when more than four alternatives are present inside a
443        bracket.
445    11. Empty match is not possible, when the minimum length is greater than zero,
446        and there is no \K in the pattern. JIT should avoid empty match checks in
447        such cases.
449    12. In a caseless character class with UCP support, when a character with more
450        than one alternative case was not the first character of a range, not all
451        the alternative cases were added to the class. For example, s and \x{17f}
452        are both alternative cases for S: the class [RST] was handled correctly,
453        but [R-T] was not.
455    13. The configure.ac file always checked for pthread support when JIT was
456        enabled. This is not used in Windows, so I have put this test inside a
457        check for the presence of windows.h (which was already tested for).
459    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
460        The algorithm provides a way to skip certain starting offsets, and usually
461        faster than linear prefix searches.
463    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
464        as for 'fr_FR' and 'french'. For some reason, however, it then used the
465        Windows-specific input and output files, which have 'french' screwed in.
466        So this could never have worked. One of the problems with locales is that
467        they aren't always the same. I have now updated RunTest so that it checks
468        the output of the locale test (test 3) against three different output
469        files, and it allows the test to pass if any one of them matches. With luck
470        this should make the test pass on some versions of Solaris where it was
471        failing. Because of the uncertainty, the script did not used to stop if
472        test 3 failed; it now does. If further versions of a French locale ever
473        come to light, they can now easily be added.
475    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
476        there was a message during ./configure, but it did not stop. This now
477        provokes an error. The invalid example in README has been corrected.
478        If a value less than the minimum is given, the minimum value has always
479        been used, but now a warning is given.
481    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
482        was a bug in the test system, which is now fixed. Also, the list of various
483        configurations that are tested for each release did not have one with both
484        16/32 bits and --enable-bar-anycrlf. It now does.
486    18. pcretest was missing "-C bsr" for displaying the \R default setting.
488    19. Little endian PowerPC systems are supported now by the JIT compiler.
490    20. The fast forward newline mechanism could enter to an infinite loop on
491        certain invalid UTF-8 input. Although we don't support these cases
492        this issue can be fixed by a performance optimization.
494    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
495        not take account if existing stack usage. There is now a new global
496        variable called pcre_stack_guard that can be set to point to an external
497        function to check stack availability. It is called at the start of
498        processing every parenthesized group.
500    22. A typo in the code meant that in ungreedy mode the max/min qualifier
501        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
502        not match "ab".
504    23. When UTF was disabled, the JIT program reported some incorrect compile
505        errors. These messages are silenced now.
507    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
508        compiler.
510    25. Change all the temporary files used in RunGrepTest to be different to those
511        used by RunTest so that the tests can be run simultaneously, for example by
512        "make -j check".
515    Version 8.34 15-December-2013
516    -----------------------------
518    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
519        executable memory. Patch inspired by Carsten Klein.
521    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
522        this macro is never tested and has no effect, because the work to support
523        coverage involves only compiling and linking options and special targets in
524        the Makefile. The comment in config.h implied that defining the macro would
525        enable coverage support, which is totally false. There was also support for
526        setting this macro in the CMake files (my fault, I just copied it from
527        configure). SUPPORT_GCOV has now been removed.
529    3.  Make a small performance improvement in strlen16() and strlen32() in
530        pcretest.
532    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
533        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
534        these cases). There was also one in pcretest.c.
536    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
538    6.  In UTF mode, the code for checking whether a group could match an empty
539        string (which is used for indefinitely repeated groups to allow for
540        breaking an infinite loop) was broken when the group contained a repeated
541        negated single-character class with a character that occupied more than one
542        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
543        UTF-8 mode). The effect was undefined: the group might or might not be
544        deemed as matching an empty string, or the program might have crashed.
546    7.  The code for checking whether a group could match an empty string was not
547        recognizing that \h, \H, \v, \V, and \R must match a character.
549    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
550        an empty string. If it can, pcretest shows this in its information output.
552    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
553        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
554        matched by pcre_exec() without using JIT:
556        (a) If the rest of the pattern did not match after a maximal run of
557            grapheme clusters, the code for backing up to try with fewer of them
558            did not always back up over a full grapheme when characters that do not
559            have the modifier quality were involved, e.g. Hangul syllables.
561        (b) If the match point in a subject started with modifier character, and
562            there was no match, the code could incorrectly back up beyond the match
563            point, and potentially beyond the first character in the subject,
564            leading to a segfault or an incorrect match result.
566    10. A conditional group with an assertion condition could lead to PCRE
567        recording an incorrect first data item for a match if no other first data
568        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
569        first data item, and therefore matched "ca" after "c" instead of at the
570        start.
572    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
573        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
575    12. The source of pcregrep now includes z/OS-specific code so that it can be
576        compiled for z/OS as part of the special z/OS distribution.
578    13. Added the -T and -TM options to pcretest.
580    14. The code in pcre_compile.c for creating the table of named capturing groups
581        has been refactored. Instead of creating the table dynamically during the
582        actual compiling pass, the information is remembered during the pre-compile
583        pass (on the stack unless there are more than 20 named groups, in which
584        case malloc() is used) and the whole table is created before the actual
585        compile happens. This has simplified the code (it is now nearly 150 lines
586        shorter) and prepared the way for better handling of references to groups
587        with duplicate names.
589    15. A back reference to a named subpattern when there is more than one of the
590        same name now checks them in the order in which they appear in the pattern.
591        The first one that is set is used for the reference. Previously only the
592        first one was inspected. This change makes PCRE more compatible with Perl.
594    16. Unicode character properties were updated from Unicode 6.3.0.
596    17. The compile-time code for auto-possessification has been refactored, based
597        on a patch by Zoltan Herczeg. It now happens after instead of during
598        compilation. The code is cleaner, and more cases are handled. The option
599        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
600        options in pcretest are provided to set it. It can also be set by
601        (*NO_AUTO_POSSESS) at the start of a pattern.
603    18. The character VT has been added to the default ("C" locale) set of
604        characters that match \s and are generally treated as white space,
605        following this same change in Perl 5.18. There is now no difference between
606        "Perl space" and "POSIX space". Whether VT is treated as white space in
607        other locales depends on the locale.
609    19. The code for checking named groups as conditions, either for being set or
610        for being recursed, has been refactored (this is related to 14 and 15
611        above). Processing unduplicated named groups should now be as fast at
612        numerical groups, and processing duplicated groups should be faster than
613        before.
615    20. Two patches to the CMake build system, by Alexander Barkov:
617          (1) Replace the "source" command by "." in CMakeLists.txt because
618              "source" is a bash-ism.
620          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
621              without these the CMake build does not work on Solaris.
623    21. Perl has changed its handling of \8 and \9. If there is no previously
624        encountered capturing group of those numbers, they are treated as the
625        literal characters 8 and 9 instead of a binary zero followed by the
626        literals. PCRE now does the same.
628    22. Following Perl, added \o{} to specify codepoints in octal, making it
629        possible to specify values greater than 0777 and also making them
630        unambiguous.
632    23. Perl now gives an error for missing closing braces after \x{... instead of
633        treating the string as literal. PCRE now does the same.
635    24. RunTest used to grumble if an inappropriate test was selected explicitly,
636        but just skip it when running all tests. This make it awkward to run ranges
637        of tests when one of them was inappropriate. Now it just skips any
638        inappropriate tests, as it always did when running all tests.
640    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
641        character types such as \d or \w, too many callouts were inserted, and the
642        data that they returned was rubbish.
644    26. In UCP mode, \s was not matching two of the characters that Perl matches,
645        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
646        were matched by \h. The code has now been refactored so that the lists of
647        the horizontal and vertical whitespace characters used for \h and \v (which
648        are defined only in one place) are now also used for \s.
650    27. Add JIT support for the 64 bit TileGX architecture.
651        Patch by Jiong Wang (Tilera Corporation).
653    28. Possessive quantifiers for classes (both explicit and automatically
654        generated) now use special opcodes instead of wrapping in ONCE brackets.
656    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
657        (because it's meaningless), this was not happening when PCRE_CASELESS was
658        set. Not wrong, but inefficient.
660    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
661        properties for \w, \d, etc) is present in a test regex. Otherwise if the
662        test contains no characters greater than 255, Perl doesn't realise it
663        should be using Unicode semantics.
665    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
666        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
667        does in Unicode mode.
669    32. Added the "forbid" facility to pcretest so that putting tests into the
670        wrong test files can sometimes be quickly detected.
672    33. There is now a limit (default 250) on the depth of nesting of parentheses.
673        This limit is imposed to control the amount of system stack used at compile
674        time. It can be changed at build time by --with-parens-nest-limit=xxx or
675        the equivalent in CMake.
677    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
678        errors. Perl warns for these when in warning mode, but PCRE has no facility
679        for giving warnings.
681    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
682        However, this was not working for (?!) because it is optimized to (*FAIL),
683        for which PCRE does not allow quantifiers. The optimization is now disabled
684        when a quantifier follows (?!). I can't see any use for this, but it makes
685        things uniform.
687    36. Perl no longer allows group names to start with digits, so I have made this
688        change also in PCRE. It simplifies the code a bit.
690    37. In extended mode, Perl ignores spaces before a + that indicates a
691        possessive quantifier. PCRE allowed a space before the quantifier, but not
692        before the possessive +. It now does.
694    38. The use of \K (reset reported match start) within a repeated possessive
695        group such as (a\Kb)*+ was not working.
697    40. Document that the same character tables must be used at compile time and
698        run time, and that the facility to pass tables to pcre_exec() and
699        pcre_dfa_exec() is for use only with saved/restored patterns.
701    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
702        features for Builds with MSVC:
704        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
705           builds). The .rc files can be used to set FileDescription and many other
706           attributes.
708        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
709           This allows higher-level build scripts which want .pdb files to avoid
710           hard-coding the exact files needed."
712    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
713        mean "start of word" and "end of word", respectively, as a transition aid.
715    43. A minimizing repeat of a class containing codepoints greater than 255 in
716        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
717        compiled to use the heap for recursion.
719    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
720        is configured.
723    Version 8.33 28-May-2013
724    ------------------------
726    1.  Added 'U' to some constants that are compared to unsigned integers, to
727        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
728        variables that are added to signed variables, to ensure the result is
729        signed and can be negated.
731    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
732        CMake config files.
734    3.  Revise the creation of config.h.generic so that all boolean macros are
735        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
736        overriding via -D on the command line possible.
738    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
739        to unsigned int is reported to make a quite noticeable speed difference in
740        a specific Windows environment. Testing on Linux did also appear to show
741        some benefit (and it is clearly not harmful). Also fixed the definition of
742        Xop which should be unsigned.
744    5.  Related to (4), changing the definition of the intermediate variable cc
745        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
746        improvements.
748    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
749        unnecessary spaces.
751    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
752        and later.
754    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
756    9.  Optimizing fast_forward_start_bits in JIT.
758    10. Adding support for callouts in JIT, and fixing some issues revealed
759        during this work. Namely:
761        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
763        (b) Minimum length was not checked before the matching is started.
765    11. The value of capture_last that is passed to callouts was incorrect in some
766        cases when there was a capture on one path that was subsequently abandoned
767        after a backtrack. Also, the capture_last value is now reset after a
768        recursion, since all captures are also reset in this case.
770    12. The interpreter no longer returns the "too many substrings" error in the
771        case when an overflowing capture is in a branch that is subsequently
772        abandoned after a backtrack.
774    13. In the pathological case when an offset vector of size 2 is used, pcretest
775        now prints out the matched string after a yield of 0 or 1.
777    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
778        Only supported by the JIT compiler at the moment.
780    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
782    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
783        offset of the starting point of the matching process, provided the offsets
784        vector is large enough.
786    17. The \A escape now records a lookbehind value of 1, though its execution
787        does not actually inspect the previous character. This is to ensure that,
788        in partial multi-segment matching, at least one character from the old
789        segment is retained when a new segment is processed. Otherwise, if there
790        are no lookbehinds in the pattern, \A might match incorrectly at the start
791        of a new segment.
793    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
795    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
796        gives some modest performance improvement in 8-bit mode.
798    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
799        be expressed in certain programming languages using Universal Character
800        Names.
802    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
803        which points out that "non characters" are not "characters that may not
804        appear in Unicode strings" but rather "characters that are reserved for
805        internal use and have only local meaning".
807    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
808        there was a conditional group that depended on an assertion, if the
809        assertion was false, the callout that immediately followed the alternation
810        in the condition was skipped when pcre_exec() was used for matching.
812    23. Allow an explicit callout to be inserted before an assertion that is the
813        condition for a conditional group, for compatibility with automatic
814        callouts, which always insert a callout at this point.
816    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
817        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
819    25. (*PRUNE) is now supported by the JIT compiler.
821    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
823    27. Fix the case where there are two or more SKIPs with arguments that may be
824        ignored.
826    28. (*SKIP) is now supported by the JIT compiler.
828    29. (*THEN) is now supported by the JIT compiler.
830    30. Update RunTest with additional test selector options.
832    31. The way PCRE handles backtracking verbs has been changed in two ways.
834        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
835        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
836        backtracking. In some cases this makes it more Perl-compatible, but Perl's
837        rather obscure rules do not always do the same thing.
839        (2) Previously, backtracking verbs were confined within assertions. This is
840        no longer the case for positive assertions, except for (*ACCEPT). Again,
841        this sometimes improves Perl compatibility, and sometimes does not.
843    32. A number of tests that were in test 2 because Perl did things differently
844        have been moved to test 1, because either Perl or PCRE has changed, and
845        these tests are now compatible.
847    32. Backtracking control verbs are now handled in the same way in JIT and
848        interpreter.
850    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
851        contained a forward subroutine reference caused a compile error.
853    34. Auto-detect and optimize limited repetitions in JIT.
855    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
856        blocking (*UTF) etc.
858    36. In the interpreter, maximizing pattern repetitions for characters and
859        character types now use tail recursion, which reduces stack usage.
861    37. The value of the max lookbehind was not correctly preserved if a compiled
862        and saved regex was reloaded on a host of different endianness.
864    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
865        of the compiled pattern block, expand the flags field from 16 to 32 bits
866        because it was almost full.
868    39. Try madvise first before posix_madvise.
870    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
871        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
872        original change locked out all matches of empty strings. This has been
873        changed so that one match of an empty string per line is recognized.
874        Subsequent searches on the same line (for colouring or for --only-matching,
875        for example) do not recognize empty strings.
877    41. Applied a user patch to fix a number of spelling mistakes in comments.
879    42. Data lines longer than 65536 caused pcretest to crash.
881    43. Clarified the data type for length and startoffset arguments for pcre_exec
882        and pcre_dfa_exec in the function-specific man pages, where they were
883        explicitly stated to be in bytes, never having been updated. I also added
884        some clarification to the pcreapi man page.
886    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
887        a segmentation fault.
890    Version 8.32 30-November-2012
891    -----------------------------
893    1.  Improved JIT compiler optimizations for first character search and single
894        character iterators.
896    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
897        Patch by Daniel Richard G.
899    3.  Single character iterator optimizations in the JIT compiler.
901    4.  Improved JIT compiler optimizations for character ranges.
903    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
904        Reported by Giuseppe D'Angelo.
906    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
907        of a line, was being set incorrectly in cases where .* appeared inside
908        atomic brackets at the start of a pattern, or where there was a subsequent
909        *PRUNE or *SKIP.
911    7.  Improved instruction cache flush for POWER/PowerPC.
912        Patch by Daniel Richard G.
914    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
915        grep:
917        (a) There is now no limit to the number of patterns to be matched.
919        (b) An error is given if a pattern is too long.
921        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
922            are now supported.
924        (d) --exclude-from and --include-from (multiple use) have been added.
926        (e) Exclusions and inclusions now apply to all files and directories, not
927            just to those obtained from scanning a directory recursively.
929        (f) Multiple uses of -f and --file-list are now supported.
931        (g) In a Windows environment, the default for -d has been changed from
932            "read" (the GNU grep default) to "skip", because otherwise the presence
933            of a directory in the file list provokes an error.
935        (h) The documentation has been revised and clarified in places.
937    9.  Improve the matching speed of capturing brackets.
939    10. Changed the meaning of \X so that it now matches a Unicode extended
940        grapheme cluster.
942    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
943        out POSIX threads when JIT support is configured.
945    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
947    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
948        structure could go wrong in environments where size_t is not the same size
949        as int.
951    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
952        set.
954    15. The EBCDIC support had decayed; later updates to the code had included
955        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
956        general tidy up of EBCDIC-related issues, and the documentation was also
957        not quite right. There is now a test that can be run on ASCII systems to
958        check some of the EBCDIC-related things (but is it not a full test).
960    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
961        in a small tidy to the code.
963    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
965    18. If the --only-matching (-o) option in pcregrep is specified multiple
966        times, each one causes appropriate output. For example, -o1 -o2 outputs the
967        substrings matched by the 1st and 2nd capturing parentheses. A separating
968        string can be specified by --om-separator (default empty).
970    19. Improving the first n character searches.
972    20. Turn case lists for horizontal and vertical white space into macros so that
973        they are defined only once.
975    21. This set of changes together give more compatible Unicode case-folding
976        behaviour for characters that have more than one other case when UCP
977        support is available.
979        (a) The Unicode property table now has offsets into a new table of sets of
980            three or more characters that are case-equivalent. The MultiStage2.py
981            script that generates these tables (the pcre_ucd.c file) now scans
982            CaseFolding.txt instead of UnicodeData.txt for character case
983            information.
985        (b) The code for adding characters or ranges of characters to a character
986            class has been abstracted into a generalized function that also handles
987            case-independence. In UTF-mode with UCP support, this uses the new data
988            to handle characters with more than one other case.
990        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
991            whose other case is greater than 256 are now correctly matched
992            caselessly. Previously, the high codepoint matched the low one, but not
993            vice versa.
995        (d) The processing of \h, \H, \v, and \ in character classes now makes use
996            of the new class addition function, using character lists defined as
997            macros alongside the case definitions of 20 above.
999        (e) Caseless back references now work with characters that have more than
1000            one other case.
1002        (f) General caseless matching of characters with more than one other case
1003            is supported.
1005    22. Unicode character properties were updated from Unicode 6.2.0
1007    23. Improved CMake support under Windows. Patch by Daniel Richard G.
1009    24. Add support for 32-bit character strings, and UTF-32
1011    25. Major JIT compiler update (code refactoring and bugfixing).
1012        Experimental Sparc 32 support is added.
1014    26. Applied a modified version of Daniel Richard G's patch to create
1015        pcre.h.generic and config.h.generic by "make" instead of in the
1016        PrepareRelease script.
1018    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
1019        pcre_compile.c when checking for a zero character.
1021    28. Introducing a native interface for JIT. Through this interface, the compiled
1022        machine code can be directly executed. The purpose of this interface is to
1023        provide fast pattern matching, so several sanity checks are not performed.
1024        However, feature tests are still performed. The new interface provides
1025        1.4x speedup compared to the old one.
1027    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
1028        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
1029        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
1031    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
1032        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
1033        the "old" RFC 2279). Instead, it ended up passing a negative length to
1034        pcre_exec().
1036    31. Add support for GCC's visibility feature to hide internal functions.
1038    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
1039        "unknown -C option" after outputting 0 or 1.
1041    33. There is now support for generating a code coverage report for the test
1042        suite in environments where gcc is the compiler and lcov is installed. This
1043        is mainly for the benefit of the developers.
1045    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
1046        unaddressable using valgrind annotations, allowing valgrind to detect
1047        invalid memory accesses. This is mainly for the benefit of the developers.
1049    25. (*UTF) can now be used to start a pattern in any of the three libraries.
1051    26. Give configure error if --enable-cpp but no C++ compiler found.
1054    Version 8.31 06-July-2012
1055    -------------------------
1057    1.  Fixing a wrong JIT test case and some compiler warnings.
1059    2.  Removed a bashism from the RunTest script.
1061    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
1062        to unsigned type, result still unsigned" that was given by an MS compiler
1063        on encountering the code "-sizeof(xxx)".
1065    4.  Partial matching support is added to the JIT compiler.
1067    5.  Fixed several bugs concerned with partial matching of items that consist
1068        of more than one character:
1070        (a) /^(..)\1/ did not partially match "aba" because checking references was
1071            done on an "all or nothing" basis. This also applied to repeated
1072            references.
1074        (b) \R did not give a hard partial match if \r was found at the end of the
1075            subject.
1077        (c) \X did not give a hard partial match after matching one or more
1078            characters at the end of the subject.
1080        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
1081            a partial match for the string "\r".
1083        (e) When newline was set to CRLF, the metacharacter "." did not recognize
1084            a partial match for a CR character at the end of the subject string.
1086    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
1087        running pcretest, the text "(JIT)" added to the output whenever JIT is
1088        actually used to run the match.
1090    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
1091        or /S+[+] with a digit between 1 and 7.
1093    8.  OP_NOT now supports any UTF character not just single-byte ones.
1095    9.  (*MARK) control verb is now supported by the JIT compiler.
1097    10. The command "./RunTest list" lists the available tests without actually
1098        running any of them. (Because I keep forgetting what they all are.)
1102    12. Applied a (slightly modified) user-supplied patch that improves performance
1103        when the heap is used for recursion (compiled with --disable-stack-for-
1104        recursion). Instead of malloc and free for each heap frame each time a
1105        logical recursion happens, frames are retained on a chain and re-used where
1106        possible. This sometimes gives as much as 30% improvement.
1108    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
1109        call.
1111    14. As documented, (*COMMIT) is now confined to within a positive assertion.
1113    15. It is now possible to link pcretest with libedit as an alternative to
1114        libreadline.
1116    16. (*COMMIT) control verb is now supported by the JIT compiler.
1118    17. The Unicode data tables have been updated to Unicode 6.1.0.
1120    18. Added --file-list option to pcregrep.
1122    19. Added binary file support to pcregrep, including the -a, --binary-files,
1123        -I, and --text options.
1125    20. The madvise function is renamed for posix_madvise for QNX compatibility
1126        reasons. Fixed by Giuseppe D'Angelo.
1128    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
1130    22. Changed the option for creating symbolic links for 16-bit man pages from
1131        -s to -sf so that re-installing does not cause issues.
1133    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
1135    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
1136        matches in certain environments (the workspace was not being correctly
1137        retained). Also added to pcre_dfa_exec() a simple plausibility check on
1138        some of the workspace data at the beginning of a restart.
1140    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
1141        was not doing so when it should - probably a typo introduced by SVN 528
1142        (change 8.10/14).
1144    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
1145        \w+ when the character tables indicated that \x{c4} was a word character.
1146        There were several related cases, all because the tests for doing a table
1147        lookup were testing for characters less than 127 instead of 255.
1149    27. If a pattern contains capturing parentheses that are not used in a match,
1150        their slots in the ovector are set to -1. For those that are higher than
1151        any matched groups, this happens at the end of processing. In the case when
1152        there were back references that the ovector was too small to contain
1153        (causing temporary malloc'd memory to be used during matching), and the
1154        highest capturing number was not used, memory off the end of the ovector
1155        was incorrectly being set to -1. (It was using the size of the temporary
1156        memory instead of the true size.)
1158    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
1159        ovector size, it uses memory at the end of the block that it has got.
1161    29. Check for an overlong MARK name and give an error at compile time. The
1162        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
1164    30. JIT compiler update.
1166    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
1167        Rill for the patch.
1169    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
1171    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
1173    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
1174        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
1175        was enabled.
1177    35. Improve JIT code generation for greedy plus quantifier.
1179    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
1180        1 to "aa" instead of to an empty string. The bug affected repeated groups
1181        that could potentially match an empty string.
1183    37. Optimizing single character iterators in JIT.
1185    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
1186        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
1187        codepoints that are too big for the mode are faulted, and in a UTF mode,
1188        disallowed codepoints are also faulted.
1190    39. If PCRE was compiled with UTF support, in three places in the DFA
1191        matcher there was code that should only have been obeyed in UTF mode, but
1192        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
1193        processing when bytes with values greater than 127 were present. In 16-bit
1194        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
1195        both cases the values are those that cannot be the first data item in a UTF
1196        character. The three items that might have provoked this were recursions,
1197        possessively repeated groups, and atomic groups.
1199    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
1200        and pcregrep, because some OS require shared objects to be explicitly
1201        passed to ld, causing the link step to fail if they are not.
1203    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
1204        mode, patterns that started with \h* or \R* might be incorrectly matched.
1207    Version 8.30 04-February-2012
1208    -----------------------------
1210    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
1211        name is defined in ctype.h.
1213    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
1214        only in quite long subpatterns.
1216    3.  Removed the function pcre_info(), which has been obsolete and deprecated
1217        since it was replaced by pcre_fullinfo() in February 2000.
1219    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
1220        match a (*MARK), and the match failed at the start of the subject, a
1221        reference to memory before the start of the subject could occur. This bug
1222        was introduced by fix 17 of release 8.21.
1224    5.  A reference to an unset group with zero minimum repetition was giving
1225        totally wrong answers (in non-JavaScript-compatibility mode). For example,
1226        /(another)?(\1?)test/ matched against "hello world test". This bug was
1227        introduced in release 8.13.
1229    6.  Add support for 16-bit character strings (a large amount of work involving
1230        many changes and refactorings).
1232    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
1233        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
1234        from a file.
1236    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
1237        rounding is not applied in this particular case).
1239    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
1240        if they appear, or are escaped, in patterns.
1242    10. Get rid of a number of -Wunused-but-set-variable warnings.
1244    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
1245        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
1246        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
1247        also returns the mark "x". This bug applied to capturing parentheses,
1248        non-capturing parentheses, and atomic parentheses. It also applied to some
1249        assertions.
1251    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
1252        information out of configure.ac instead of relying on pcre.h.generic, which
1253        is not stored in the repository.
1255    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
1256        -lreadline.
1258    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
1260    15. Applied Graycode's patch to put the top-level frame on the stack rather
1261        than the heap when not using the stack for recursion. This gives a
1262        performance improvement in many cases when recursion is not deep.
1264    16. Experimental code added to "pcretest -C" to output the stack frame size.
1267    Version 8.21 12-Dec-2011
1268    ------------------------
1270    1.  Updating the JIT compiler.
1272    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
1273        are added as well.
1275    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
1276        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
1277        calling _pcre_jit_exec. Some extra comments are added.
1279    4.  (*MARK) settings inside atomic groups that do not contain any capturing
1280        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
1281        was introduced by change 18 for 8.20.
1283    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
1284        ECMA-262 standard.
1286    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
1287        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
1288        This bug was probably introduced by change 9 of 8.13.
1290    7.  While fixing 6 above, I noticed that a number of other items were being
1291        incorrectly rejected as "not fixed length". This arose partly because newer
1292        opcodes had not been added to the fixed-length checking code. I have (a)
1293        corrected the bug and added tests for these items, and (b) arranged for an
1294        error to occur if an unknown opcode is encountered while checking for fixed
1295        length instead of just assuming "not fixed length". The items that were
1296        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
1297        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
1298        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
1300    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
1301        being incorrectly compiled and would have given unpredicatble results.
1303    9.  A possessively repeated subpattern with minimum repeat count greater than
1304        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
1305        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
1306        the first (A) could occur when it should not.
1308    10. Add a cast and remove a redundant test from the code.
1310    11. JIT should use pcre_malloc/pcre_free for allocation.
1312    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
1313        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
1314        is anything other than /usr, -L is still shown).
1316    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
1318    14. Perl does not support \N without a following name in a [] class; PCRE now
1319        also gives an error.
1321    15. If a forward reference was repeated with an upper limit of around 2000,
1322        it caused the error "internal error: overran compiling workspace". The
1323        maximum number of forward references (including repeats) was limited by the
1324        internal workspace, and dependent on the LINK_SIZE. The code has been
1325        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
1326        the default depends on LINK_SIZE. There is a new upper limit (for safety)
1327        of around 200,000 forward references. While doing this, I also speeded up
1328        the filling in of repeated forward references.
1330    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
1331        incorrectly expecting the subject to contain another "a" after the start.
1333    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
1334        in the match, the SKIP should be ignored. This was not happening; instead
1335        the SKIP was being treated as NOMATCH. For patterns such as
1336        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
1337        tested.
1339    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
1340        now much more compatible with Perl, in particular in cases where the result
1341        is a non-match for a non-anchored pattern. For example, if
1342        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
1343        "m", where previously it did not return a name. A side effect of this
1344        change is that for partial matches, the last encountered mark name is
1345        returned, as for non matches. A number of tests that were previously not
1346        Perl-compatible have been moved into the Perl-compatible test files. The
1347        refactoring has had the pleasing side effect of removing one argument from
1348        the match() function, thus reducing its stack requirements.
1350    19. If the /S+ option was used in pcretest to study a pattern using JIT,
1351        subsequent uses of /S (without +) incorrectly behaved like /S+.
1353    21. Retrieve executable code size support for the JIT compiler and fixing
1354        some warnings.
1356    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
1357        not work when the shorter character appeared right at the end of the
1358        subject string.
1360    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
1361        systems.
1363    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
1364        output it when the /M option is used in pcretest.
1366    25. The CheckMan script was not being included in the distribution. Also, added
1367        an explicit "perl" to run Perl scripts from the PrepareRelease script
1368        because this is reportedly needed in Windows.
1370    26. If study data was being save in a file and studying had not found a set of
1371        "starts with" bytes for the pattern, the data written to the file (though
1372        never used) was taken from uninitialized memory and so caused valgrind to
1373        complain.
1375    27. Updated RunTest.bat as provided by Sheri Pierce.
1377    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
1379    29. Computation of memory usage for the table of capturing group names was
1380        giving an unnecessarily large value.
1383    Version 8.20 21-Oct-2011
1384    ------------------------
1386    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
1387        a POSIX class. After further experiments with Perl, which convinced me that
1388        Perl has bugs and confusions, a closing square bracket is no longer allowed
1389        in a POSIX name. This bug also affected patterns with classes that started
1390        with full stops.
1392    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
1393        captured substring, but while checking the failing first alternative,
1394        substring 1 is temporarily captured. If the output vector supplied to
1395        pcre_exec() was not big enough for this capture, the yield of the function
1396        was still zero ("insufficient space for captured substrings"). This cannot
1397        be totally fixed without adding another stack variable, which seems a lot
1398        of expense for a edge case. However, I have improved the situation in cases
1399        such as /(a)(b)x|abc/ matched against "abc", where the return code
1400        indicates that fewer than the maximum number of slots in the ovector have
1401        been set.
1403    3.  Related to (2) above: when there are more back references in a pattern than
1404        slots in the output vector, pcre_exec() uses temporary memory during
1405        matching, and copies in the captures as far as possible afterwards. It was
1406        using the entire output vector, but this conflicts with the specification
1407        that only 2/3 is used for passing back captured substrings. Now it uses
1408        only the first 2/3, for compatibility. This is, of course, another edge
1409        case.
1411    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
1412        main code base, and can be used by building with --enable-jit. When this is
1413        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
1414        runtime --no-jit option is given.
1416    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
1417        ovector, the return from the function was zero, implying that there were
1418        other matches that did not fit. The correct "exactly full" value is now
1419        returned.
1421    6.  If a subpattern that was called recursively or as a subroutine contained
1422        (*PRUNE) or any other control that caused it to give a non-standard return,
1423        invalid errors such as "Error -26 (nested recursion at the same subject
1424        position)" or even infinite loops could occur.
1426    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
1427        computing the minimum length on reaching *ACCEPT, and so ended up with the
1428        wrong value of 1 rather than 0. Further investigation indicates that
1429        computing a minimum subject length in the presence of *ACCEPT is difficult
1430        (think back references, subroutine calls), and so I have changed the code
1431        so that no minimum is registered for a pattern that contains *ACCEPT.
1433    8.  If (*THEN) was present in the first (true) branch of a conditional group,
1434        it was not handled as intended. [But see 16 below.]
1436    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
1437        Sheri Pierce.
1439    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
1440        the first byte in a match must be "a".
1442    11. Change 17 for 8.13 increased the recursion depth for patterns like
1443        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
1444        pattern contains any instances of (*THEN). If it does not, the old
1445        optimizations are restored. It would be nice to do this on a per-group
1446        basis, but at the moment that is not feasible.
1448    12. In some environments, the output of pcretest -C is CRLF terminated. This
1449        broke RunTest's code that checks for the link size. A single white space
1450        character after the value is now allowed for.
1452    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
1453        For "fr", it uses the Windows-specific input and output files.
1455    14. If (*THEN) appeared in a group that was called recursively or as a
1456        subroutine, it did not work as intended. [But see next item.]
1458    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
1459        pattern fragments (but not containing any | characters). If A and B are
1460        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
1461        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
1462        D. In other words, Perl considers parentheses that do not contain any |
1463        characters to be part of a surrounding alternative, whereas PCRE was
1464        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
1465        differently. PCRE now behaves in the same way as Perl, except in the case
1466        of subroutine/recursion calls such as (?1) which have in any case always
1467        been different (but PCRE had them first :-).
1469    16. Related to 15 above: Perl does not treat the | in a conditional group as
1470        creating alternatives. Such a group is treated in the same way as an
1471        ordinary group without any | characters when processing (*THEN). PCRE has
1472        been changed to match Perl's behaviour.
1474    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
1475        RunGrepTest script failed.
1477    18. Change 22 for version 13 caused atomic groups to use more stack. This is
1478        inevitable for groups that contain captures, but it can lead to a lot of
1479        stack use in large patterns. The old behaviour has been restored for atomic
1480        groups that do not contain any capturing parentheses.
1482    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
1483        suppress the check for a minimum subject length at run time. (If it was
1484        given to pcre_exec() or pcre_dfa_exec() it did work.)
1486    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
1487        fail to work when decoding hex characters in data strings in EBCDIC
1488        environments.
1490    21. It appears that in at least one Mac OS environment, the isxdigit() function
1491        is implemented as a macro that evaluates to its argument more than once,
1492        contravening the C 90 Standard (I haven't checked a later standard). There
1493        was an instance in pcretest which caused it to go wrong when processing
1494        \x{...} escapes in subject strings. The has been rewritten to avoid using
1495        things like p++ in the argument of isxdigit().
1498    Version 8.13 16-Aug-2011
1499  ------------------------  ------------------------
1501  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 98  Version 8.13 02-Aug-2011 Line 1592  Version 8.13 02-Aug-2011
1592      tail recursion to cut down on stack usage. Unfortunately, now that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
1593      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
1594      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
1595      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
1597  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
1598      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
# Line 189  Version 8.13 02-Aug-2011 Line 1683  Version 8.13 02-Aug-2011
1683      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
1684      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
1685      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
1686      more like Perl.      more like Perl. (But see 8.20/1 above.)
1688  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
1689      was because it thought it was \N{name}, which is not supported).      was because it thought it was \N{name}, which is not supported).
# Line 224  Version 8.13 02-Aug-2011 Line 1718  Version 8.13 02-Aug-2011
1718      (a) The default value of the buffer size parameter has been increased from      (a) The default value of the buffer size parameter has been increased from
1719          8K to 20K. (The actual buffer used is three times this size.)          8K to 20K. (The actual buffer used is three times this size.)
1721      (b) The default can be changed by ./configure --with-pcregrep-bufsiz when      (b) The default can be changed by ./configure --with-pcregrep-bufsize when
1722          PCRE is built.          PCRE is built.
1724      (c) A --buffer-size=n option has been added to pcregrep, to allow the size      (c) A --buffer-size=n option has been added to pcregrep, to allow the size
# Line 245  Version 8.13 02-Aug-2011 Line 1739  Version 8.13 02-Aug-2011
1739  47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a  47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
1740      complete match instead of a partial match. This bug was dependent on both      complete match instead of a partial match. This bug was dependent on both
1741      the PCRE_UTF8 and PCRE_DOTALL options being set.      the PCRE_UTF8 and PCRE_DOTALL options being set.
1743  48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the  48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
1744      starting byte set, because \b was not being ignored.      starting byte set, because \b was not being ignored.
1747  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
# Line 900  Version 7.9 11-Apr-09 Line 2394  Version 7.9 11-Apr-09
2394  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
2395      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
2396      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2397      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2398        8.33.]
2400  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
2401      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 1143  Version 7.7 07-May-08 Line 2638  Version 7.7 07-May-08
2638      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2639      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2640      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2641      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2642      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2643      was subsequently set up correctly.)      was subsequently set up correctly.)

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