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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.3 05-Jul-07  Version 8.13 30-Apr-2011
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
9    2.  Two minor typos in pcre_internal.h have been fixed.
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
176    33. Previously, PCRE did not allow quantification of assertions. However, Perl
177        does, and because of capturing effects, quantifying parenthesized
178        assertions may at times be useful. Quantifiers are now allowed for
179        parenthesized assertions.
181    34. A minor code tidy in pcre_compile() when checking options for \R usage.
183    35. \g was being checked for fancy things in a character class, when it should
184        just be a literal "g".
186    36. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
187        appearance of a nested POSIX class supersedes an apparent external class.
188        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
189        unescaped square brackets may also appear as part of class names. For
190        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
191        more like Perl.
193    37. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
194        was because it thought it was \N{name}, which is not supported).
197    Version 8.12 15-Jan-2011
198    ------------------------
200    1.  Fixed some typos in the markup of the man pages, and wrote a script that
201        checks for such things as part of the documentation building process.
203    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
204        --match-limit and --recursion-limit options (added for 8.11). In
205        particular, this made one of the standard tests fail. (The integer value
206        went into the wrong half of a long int.)
208    3.  If the --colour option was given to pcregrep with -v (invert match), it
209        did strange things, either producing crazy output, or crashing. It should,
210        of course, ignore a request for colour when reporting lines that do not
211        match.
213    4.  Another pcregrep bug caused similar problems if --colour was specified with
214        -M (multiline) and the pattern match finished with a line ending.
216    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
217        matched in multiline mode, the following line was shown as part of the
218        match. This seems wrong, so I have changed it.
220    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
221        the check for further matches in the same line (so they could be coloured)
222        to overrun the end of the current line. If another match was found, it was
223        incorrectly shown (and then shown again when found in the next line).
225    7.  If pcregrep was compiled under Windows, there was a reference to the
226        function pcregrep_exit() before it was defined. I am assuming this was
227        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
228        reported by a user. I've moved the definition above the reference.
231    Version 8.11 10-Dec-2010
232    ------------------------
234    1.  (*THEN) was not working properly if there were untried alternatives prior
235        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
236        backtracked to try for "b" instead of moving to the next alternative branch
237        at the same level (in this case, to look for "c"). The Perl documentation
238        is clear that when (*THEN) is backtracked onto, it goes to the "next
239        alternative in the innermost enclosing group".
241    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
242        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
243        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
244        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
245        (*THEN).
247    3.  If \s appeared in a character class, it removed the VT character from
248        the class, even if it had been included by some previous item, for example
249        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
250        of \s, but is part of the POSIX "space" class.)
252    4.  A partial match never returns an empty string (because you can always
253        match an empty string at the end of the subject); however the checking for
254        an empty string was starting at the "start of match" point. This has been
255        changed to the "earliest inspected character" point, because the returned
256        data for a partial match starts at this character. This means that, for
257        example, /(?<=abc)def/ gives a partial match for the subject "abc"
258        (previously it gave "no match").
260    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
261        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
262        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
263        has an implication that the given string is incomplete (because a partial
264        match is preferred over a full match). For this reason, these items now
265        give a partial match in this situation. [Aside: previously, the one case
266        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
267        match rather than a full match, which was wrong by the old rules, but is
268        now correct.]
270    6.  There was a bug in the handling of #-introduced comments, recognized when
271        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
272        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
273        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
274        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
275        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
276        places in pcre_compile().
278    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
279        comments when looking ahead for named forward references to subpatterns,
280        the only newline sequence it recognized was NL. It now handles newlines
281        according to the set newline convention.
283    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
284        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
285        cater for a lack of strerror(). These oversights have been fixed.
287    9.  Added --match-limit and --recursion-limit to pcregrep.
289    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
291    11. When the -o option was used, pcregrep was setting a return code of 1, even
292        when matches were found, and --line-buffered was not being honoured.
294    12. Added an optional parentheses number to the -o and --only-matching options
295        of pcregrep.
297    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
298        can match an empty string. The code to do it in pcretest and pcredemo
299        needed fixing:
301        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
302            only one byte after an empty string match just before CRLF (this case
303            just got forgotten; "any" and "anycrlf" were OK).
305        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
306            mode when an empty string match preceded an ASCII character followed by
307            a non-ASCII character. (The code for advancing by one character rather
308            than one byte was nonsense.)
310        (c) The pcredemo.c sample program did not have any code at all to handle
311            the cases when CRLF is a valid newline sequence.
313    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
314        as a starting offset was within the subject string. There is now a new
315        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
316        negative or greater than the length of the string. In order to test this,
317        pcretest is extended to allow the setting of negative starting offsets.
319    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
320        starting offset points to the beginning of a UTF-8 character was
321        unnecessarily clumsy. I tidied it up.
323    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
324        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
326    17. Nobody had reported that the --include_dir option, which was added in
327        release 7.7 should have been called --include-dir (hyphen, not underscore)
328        for compatibility with GNU grep. I have changed it to --include-dir, but
329        left --include_dir as an undocumented synonym, and the same for
330        --exclude-dir, though that is not available in GNU grep, at least as of
331        release 2.5.4.
333    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
334        characters from a string of bytes) have been redefined so as not to use
335        loops, in order to improve performance in some environments. At the same
336        time, I abstracted some of the common code into auxiliary macros to save
337        repetition (this should not affect the compiled code).
339    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
340        compile-time error is now given if \c is not followed by an ASCII
341        character, that is, a byte less than 128. (In EBCDIC mode, the code is
342        different, and any byte value is allowed.)
344    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
345        START_OPTIMIZE option, which is now allowed at compile time - but just
346        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
347        to pcregrep and other applications that have no direct access to PCRE
348        options. The new /Y option in pcretest sets this option when calling
349        pcre_compile().
351    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
352        back references. Groups containing recursive back references were forced to
353        be atomic by that change, but in the case of named groups, the amount of
354        memory required was incorrectly computed, leading to "Failed: internal
355        error: code overflow". This has been fixed.
357    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
358        pcretest.c, to avoid build problems in some Borland environments.
361    Version 8.10 25-Jun-2010
362    ------------------------
364    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
365        THEN.
367    2.  (*ACCEPT) was not working when inside an atomic group.
369    3.  Inside a character class, \B is treated as a literal by default, but
370        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
371        causes the error). The code is unchanged, but I tidied the documentation.
373    4.  Inside a character class, PCRE always treated \R and \X as literals,
374        whereas Perl faults them if its -w option is set. I have changed PCRE so
375        that it faults them when PCRE_EXTRA is set.
377    5.  Added support for \N, which always matches any character other than
378        newline. (It is the same as "." when PCRE_DOTALL is not set.)
380    6.  When compiling pcregrep with newer versions of gcc which may have
381        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
382        declared with attribute warn_unused_result" were given. Just casting the
383        result to (void) does not stop the warnings; a more elaborate fudge is
384        needed. I've used a macro to implement this.
386    7.  Minor change to pcretest.c to avoid a compiler warning.
388    8.  Added four artifical Unicode properties to help with an option to make
389        \s etc use properties (see next item). The new properties are: Xan
390        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
392    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
393        use Unicode properties. (*UCP) at the start of a pattern can be used to set
394        this option. Modified pcretest to add /W to test this facility. Added
395        REG_UCP to make it available via the POSIX interface.
397    10. Added --line-buffered to pcregrep.
399    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
400        studied, and the match started with a letter with a code point greater than
401        127 whose first byte was different to the first byte of the other case of
402        the letter, the other case of this starting letter was not recognized
403        (#976).
405    12. If a pattern that was studied started with a repeated Unicode property
406        test, for example, \p{Nd}+, there was the theoretical possibility of
407        setting up an incorrect bitmap of starting bytes, but fortunately it could
408        not have actually happened in practice until change 8 above was made (it
409        added property types that matched character-matching opcodes).
411    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
412        possible starting bytes for non-anchored patterns.
414    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
415        \R, and also a number of cases that involve Unicode properties, both
416        explicit and implicit when PCRE_UCP is set.
418    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
419        input, it could crash or give wrong results if characters with values
420        greater than 0xc0 were present in the subject string. (Detail: it assumed
421        UTF-8 input when processing these items.)
423    16. Added a lot of (int) casts to avoid compiler warnings in systems where
424        size_t is 64-bit (#991).
426    17. Added a check for running out of memory when PCRE is compiled with
427        --disable-stack-for-recursion (#990).
429    18. If the last data line in a file for pcretest does not have a newline on
430        the end, a newline was missing in the output.
432    19. The default pcre_chartables.c file recognizes only ASCII characters (values
433        less than 128) in its various bitmaps. However, there is a facility for
434        generating tables according to the current locale when PCRE is compiled. It
435        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
436        characters, are recognized by isspace() and therefore were getting set in
437        these tables, and indeed these tables seem to approximate to ISO 8859. This
438        caused a problem in UTF-8 mode when pcre_study() was used to create a list
439        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
440        which of course cannot start UTF-8 characters. I have changed the code so
441        that only real ASCII characters (less than 128) and the correct starting
442        bytes for UTF-8 encodings are set for characters greater than 127 when in
443        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
444        altogether.)
446    20. Added the /T option to pcretest so as to be able to run tests with non-
447        standard character tables, thus making it possible to include the tests
448        used for 19 above in the standard set of tests.
450    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
451        reference to a subpattern the other side of a comment that contains an
452        opening parenthesis caused either an internal compiling error, or a
453        reference to the wrong subpattern.
456    Version 8.02 19-Mar-2010
457    ------------------------
459    1.  The Unicode data tables have been updated to Unicode 5.2.0.
461    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
462        configured.
464    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
465        original author of that file, following a query about its status.
467    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
468        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
470    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
471        quantifier applied to a forward-referencing subroutine call, could compile
472        incorrect code or give the error "internal error: previously-checked
473        referenced subpattern not found".
475    6.  Both MS Visual Studio and Symbian OS have problems with initializing
476        variables to point to external functions. For these systems, therefore,
477        pcre_malloc etc. are now initialized to local functions that call the
478        relevant global functions.
480    7.  There were two entries missing in the vectors called coptable and poptable
481        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
482        I've fixed the data, and added a kludgy way of testing at compile time that
483        the lengths are correct (equal to the number of opcodes).
485    8.  Following on from 7, I added a similar kludge to check the length of the
486        eint vector in pcreposix.c.
488    9.  Error texts for pcre_compile() are held as one long string to avoid too
489        much relocation at load time. To find a text, the string is searched,
490        counting zeros. There was no check for running off the end of the string,
491        which could happen if a new error number was added without updating the
492        string.
494    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
496    11. \K was not working if it appeared in an atomic group or in a group that
497        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
498        \K is "not well defined" if used in an assertion. PCRE now accepts it if
499        the assertion is positive, but not if it is negative.
501    12. Change 11 fortuitously reduced the size of the stack frame used in the
502        "match()" function of pcre_exec.c by one pointer. Forthcoming
503        implementation of support for (*MARK) will need an extra pointer on the
504        stack; I have reserved it now, so that the stack frame size does not
505        decrease.
507    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
508        item in branch that calls a recursion is a subroutine call - as in the
509        second branch in the above example - was incorrectly given the compile-
510        time error "recursive call could loop indefinitely" because pcre_compile()
511        was not correctly checking the subroutine for matching a non-empty string.
513    14. The checks for overrunning compiling workspace could trigger after an
514        overrun had occurred. This is a "should never occur" error, but it can be
515        triggered by pathological patterns such as hundreds of nested parentheses.
516        The checks now trigger 100 bytes before the end of the workspace.
518    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
521    Version 8.01 19-Jan-2010
522    ------------------------
524    1.  If a pattern contained a conditional subpattern with only one branch (in
525        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
526        computed the wrong minimum data length (which is of course zero for such
527        subpatterns). This could cause incorrect "no match" results.
529    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
530        the pattern is reset in the first branch, pcre_compile() failed with
531        "internal error: code overflow at offset...". This happened only when
532        the reset was to the original external option setting. (An optimization
533        abstracts leading options settings into an external setting, which was the
534        cause of this.)
536    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
537        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
538        assertion pattern did not match (meaning that the assertion was true), it
539        was incorrectly treated as false if the SKIP had been reached during the
540        matching. This also applied to assertions used as conditions.
542    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
543        assertion subpattern, including such a pattern used as a condition,
544        unpredictable results occurred, instead of the error return
547    5.  The C++ GlobalReplace function was not working like Perl for the special
548        situation when an empty string is matched. It now does the fancy magic
549        stuff that is necessary.
551    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
552        removed. (These were left over from very, very early versions of PCRE.)
554    7.  Some cosmetic changes to the code to make life easier when compiling it
555        as part of something else:
557        (a) Change DEBUG to PCRE_DEBUG.
559        (b) In pcre_compile(), rename the member of the "branch_chain" structure
560            called "current" as "current_branch", to prevent a collision with the
561            Linux macro when compiled as a kernel module.
563        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
564            prevent a collision with the Linux macro when compiled as a kernel
565            module.
567    8.  In pcre_compile() there are some checks for integer overflows that used to
568        cast potentially large values to (double). This has been changed to that
569        when building, a check for int64_t is made, and if it is found, it is used
570        instead, thus avoiding the use of floating point arithmetic. (There is no
571        other use of FP in PCRE.) If int64_t is not found, the fallback is to
572        double.
574    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
575        2005 (difference between two addresses compared to an unsigned value).
577    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
578        custom one, because of the following reported problem in Windows:
580          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
581              under Win32.
582          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
583              therefore missing the function definition.
584          - The compiler thus generates a "C" signature for the test function.
585          - The linker fails to find the "C" function.
586          - PCRE fails to configure if asked to do so against libbz2.
588    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
589        messages were output:
591          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
592          rerunning libtoolize, to keep the correct libtool macros in-tree.
593          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
595        I have done both of these things.
597    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
598        most of the time, it *can* run out if it is given a pattern that contains a
599        runaway infinite recursion. I updated the discussion in the pcrestack man
600        page.
602    13. Now that we have gone to the x.xx style of version numbers, the minor
603        version may start with zero. Using 08 or 09 is a bad idea because users
604        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
605        interpreted as invalid octal numbers. I've updated the previous comment in
606        configure.ac, and also added a check that gives an error if 08 or 09 are
607        used.
609    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
610        causing partial matching to fail when the end of the subject matched \W
611        in a UTF-8 pattern where \W was quantified with a minimum of 3.
613    15. There were some discrepancies between the declarations in pcre_internal.h
614        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
615        their definitions. The declarations used "const uschar *" and the
616        definitions used USPTR. Even though USPTR is normally defined as "const
617        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
618        reported that: "This difference in casting confuses some C++ compilers, for
619        example, SunCC recognizes above declarations as different functions and
620        generates broken code for hbpcre." I have changed the declarations to use
621        USPTR.
623    16. GNU libtool is named differently on some systems. The autogen.sh script now
624        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
625        (FreeBSD).
627    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
628        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
629        comment: "Figure out how to create a longlong from a string: strtoll and
630        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
631        instance, but it only takes 2 args instead of 3!"
633    18. A subtle bug concerned with back references has been fixed by a change of
634        specification, with a corresponding code fix. A pattern such as
635        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
636        refers, was giving matches when it shouldn't. For example, xa=xaaa would
637        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
638        same bug. Such groups have to be quantified to be useful, or contained
639        inside another quantified group. (If there's no repetition, the reference
640        can never match.) The problem arises because, having left the group and
641        moved on to the rest of the pattern, a later failure that backtracks into
642        the group uses the captured value from the final iteration of the group
643        rather than the correct earlier one. I have fixed this in PCRE by forcing
644        any group that contains a reference to itself to be an atomic group; that
645        is, there cannot be any backtracking into it once it has completed. This is
646        similar to recursive and subroutine calls.
649    Version 8.00 19-Oct-09
650    ----------------------
652    1.  The table for translating pcre_compile() error codes into POSIX error codes
653        was out-of-date, and there was no check on the pcre_compile() error code
654        being within the table. This could lead to an OK return being given in
655        error.
657    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
658        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
659        in a Windows environment.
661    3.  The pcregrep --count option prints the count for each file even when it is
662        zero, as does GNU grep. However, pcregrep was also printing all files when
663        --files-with-matches was added. Now, when both options are given, it prints
664        counts only for those files that have at least one match. (GNU grep just
665        prints the file name in this circumstance, but including the count seems
666        more useful - otherwise, why use --count?) Also ensured that the
667        combination -clh just lists non-zero counts, with no names.
669    4.  The long form of the pcregrep -F option was incorrectly implemented as
670        --fixed_strings instead of --fixed-strings. This is an incompatible change,
671        but it seems right to fix it, and I didn't think it was worth preserving
672        the old behaviour.
674    5.  The command line items --regex=pattern and --regexp=pattern were not
675        recognized by pcregrep, which required --regex pattern or --regexp pattern
676        (with a space rather than an '='). The man page documented the '=' forms,
677        which are compatible with GNU grep; these now work.
679    6.  No libpcreposix.pc file was created for pkg-config; there was just
680        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
682    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
683        when UCP support is not needed, by modifying the Python script that
684        generates it from Unicode data files. This should not matter if the module
685        is correctly used as a library, but I received one complaint about 50K of
686        unwanted data. My guess is that the person linked everything into his
687        program rather than using a library. Anyway, it does no harm.
689    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
690        was a minimum greater than 1 for a wide character in a possessive
691        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
692        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
693        character. Chaos in the form of incorrect output or a compiling loop could
694        result.
696    9.  The restrictions on what a pattern can contain when partial matching is
697        requested for pcre_exec() have been removed. All patterns can now be
698        partially matched by this function. In addition, if there are at least two
699        slots in the offset vector, the offset of the earliest inspected character
700        for the match and the offset of the end of the subject are set in them when
701        PCRE_ERROR_PARTIAL is returned.
703    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
704        synonymous with PCRE_PARTIAL, for backwards compatibility, and
705        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
706        and may be more useful for multi-segment matching.
708    11. Partial matching with pcre_exec() is now more intuitive. A partial match
709        used to be given if ever the end of the subject was reached; now it is
710        given only if matching could not proceed because another character was
711        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
712        string "Z", which now yields "no match" instead of "partial match". In the
713        case of pcre_dfa_exec(), "no match" is given if every matching path for the
714        final character ended with (*FAIL).
716    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
717        if the pattern had a "must contain" character that was already found in the
718        earlier partial match, unless partial matching was again requested. For
719        example, with the pattern /dog.(body)?/, the "must contain" character is
720        "g". If the first part-match was for the string "dog", restarting with
721        "sbody" failed. This bug has been fixed.
723    13. The string returned by pcre_dfa_exec() after a partial match has been
724        changed so that it starts at the first inspected character rather than the
725        first character of the match. This makes a difference only if the pattern
726        starts with a lookbehind assertion or \b or \B (\K is not supported by
727        pcre_dfa_exec()). It's an incompatible change, but it makes the two
728        matching functions compatible, and I think it's the right thing to do.
730    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
731        so that the demonstration program is easily available in environments where
732        PCRE has not been installed from source.
734    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
735        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
736        library.
738    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
739        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
740        is not the first non-POSIX option to be added. Clearly some people find
741        these options useful.
743    17. If a caller to the POSIX matching function regexec() passes a non-zero
744        value for nmatch with a NULL value for pmatch, the value of
745        nmatch is forced to zero.
747    18. RunGrepTest did not have a test for the availability of the -u option of
748        the diff command, as RunTest does. It now checks in the same way as
749        RunTest, and also checks for the -b option.
751    19. If an odd number of negated classes containing just a single character
752        interposed, within parentheses, between a forward reference to a named
753        subpattern and the definition of the subpattern, compilation crashed with
754        an internal error, complaining that it could not find the referenced
755        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
756        [The bug was that it was starting one character too far in when skipping
757        over the character class, thus treating the ] as data rather than
758        terminating the class. This meant it could skip too much.]
760    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
761        /g option in pcretest when the pattern contains \K, which makes it possible
762        to have an empty string match not at the start, even when the pattern is
763        anchored. Updated pcretest and pcredemo to use this option.
765    21. If the maximum number of capturing subpatterns in a recursion was greater
766        than the maximum at the outer level, the higher number was returned, but
767        with unset values at the outer level. The correct (outer level) value is
768        now given.
770    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
771        PCRE did not set those parentheses (unlike Perl). I have now found a way to
772        make it do so. The string so far is captured, making this feature
773        compatible with Perl.
775    23. The tests have been re-organized, adding tests 11 and 12, to make it
776        possible to check the Perl 5.10 features against Perl 5.10.
778    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
779        pattern matches a fixed length string. PCRE did not allow this; now it
780        does. Neither allows recursion.
782    25. I finally figured out how to implement a request to provide the minimum
783        length of subject string that was needed in order to match a given pattern.
784        (It was back references and recursion that I had previously got hung up
785        on.) This code has now been added to pcre_study(); it finds a lower bound
786        to the length of subject needed. It is not necessarily the greatest lower
787        bound, but using it to avoid searching strings that are too short does give
788        some useful speed-ups. The value is available to calling programs via
789        pcre_fullinfo().
791    26. While implementing 25, I discovered to my embarrassment that pcretest had
792        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
793        study optimizations had never been tested with that matching function.
794        Oops. What is worse, even when it was passed study data, there was a bug in
795        pcre_dfa_exec() that meant it never actually used it. Double oops. There
796        were also very few tests of studied patterns with pcre_dfa_exec().
798    27. If (?| is used to create subpatterns with duplicate numbers, they are now
799        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
800        on the other side of the coin, they are no longer allowed to have different
801        names, because these cannot be distinguished in PCRE, and this has caused
802        confusion. (This is a difference from Perl.)
804    28. When duplicate subpattern names are present (necessarily with different
805        numbers, as required by 27 above), and a test is made by name in a
806        conditional pattern, either for a subpattern having been matched, or for
807        recursion in such a pattern, all the associated numbered subpatterns are
808        tested, and the overall condition is true if the condition is true for any
809        one of them. This is the way Perl works, and is also more like the way
810        testing by number works.
813    Version 7.9 11-Apr-09
814    ---------------------
816    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
817        (pcretest), all targets were linked against these libraries. This included
818        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
819        libraries. This caused unwanted dependencies to be created. This problem
820        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
821        pcretest is linked with readline.
823    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
824        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
825        moved outside it again, because FALSE and TRUE are already defined in AIX,
826        but BOOL is not.
828    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
829        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
831    4.  The pcregrep documentation said spaces were inserted as well as colons (or
832        hyphens) following file names and line numbers when outputting matching
833        lines. This is not true; no spaces are inserted. I have also clarified the
834        wording for the --colour (or --color) option.
836    5.  In pcregrep, when --colour was used with -o, the list of matching strings
837        was not coloured; this is different to GNU grep, so I have changed it to be
838        the same.
840    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
841        each matching line was coloured. Now it goes on to look for further matches
842        of any of the test patterns, which is the same behaviour as GNU grep.
844    7.  A pattern that could match an empty string could cause pcregrep to loop; it
845        doesn't make sense to accept an empty string match in pcregrep, so I have
846        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
847        seems to be how GNU grep behaves.
849    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
850        start or after a newline", because the conditional assertion was not being
851        correctly handled. The rule now is that both the assertion and what follows
852        in the first alternative must satisfy the test.
854    9.  If auto-callout was enabled in a pattern with a conditional group whose
855        condition was an assertion, PCRE could crash during matching, both with
856        pcre_exec() and pcre_dfa_exec().
858    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
859        used for matching.
861    11. Unicode property support in character classes was not working for
862        characters (bytes) greater than 127 when not in UTF-8 mode.
864    12. Added the -M command line option to pcretest.
866    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
868    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
870    16. Added comments and documentation about mis-use of no_arg in the C++
871        wrapper.
873    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
874        from Martin Jerabek that uses macro names for all relevant character and
875        string constants.
877    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
878        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
879        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
880        these, but not everybody uses configure.
882    19. A conditional group that had only one branch was not being correctly
883        recognized as an item that could match an empty string. This meant that an
884        enclosing group might also not be so recognized, causing infinite looping
885        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
886        with the subject "ab", where knowledge that the repeated group can match
887        nothing is needed in order to break the loop.
889    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
890        exec(), but without supplying a callout function, matching went wrong.
892    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
893        leak if the size of the offset vector was greater than 30. When the vector
894        is smaller, the saved offsets during recursion go onto a local stack
895        vector, but for larger vectors malloc() is used. It was failing to free
896        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
897        error, in fact).
899    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
900        heapframe that is used only when UTF-8 support is enabled. This caused no
901        problem, but was untidy.
903    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
904        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
905        included within another project.
907    24. Steven Van Ingelgem's patches to add more options to the CMake support,
908        slightly modified by me:
910          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
911              not building pcregrep.
913          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
914              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
916    25. Forward references, both numeric and by name, in patterns that made use of
917        duplicate group numbers, could behave incorrectly or give incorrect errors,
918        because when scanning forward to find the reference group, PCRE was not
919        taking into account the duplicate group numbers. A pattern such as
920        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
922    26. Changed a few more instances of "const unsigned char *" to USPTR, making
923        the feature of a custom pointer more persuasive (as requested by a user).
925    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
926        pcretest.c, inside #ifndefs, because it seems they are sometimes already
927        pre-defined.
929    28. Added support for (*UTF8) at the start of a pattern.
931    29. Arrange for flags added by the "release type" setting in CMake to be shown
932        in the configuration summary.
935    Version 7.8 05-Sep-08
936    ---------------------
938    1.  Replaced UCP searching code with optimized version as implemented for Ad
939        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
940        stage table and inline lookup instead of a function, giving speed ups of 2
941        to 5 times on some simple patterns that I tested. Permission was given to
942        distribute the MultiStage2.py script that generates the tables (it's not in
943        the tarball, but is in the Subversion repository).
945    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
946        scripts.
948    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
949        a group with a zero qualifier. The result of the study could be incorrect,
950        or the function might crash, depending on the pattern.
952    4.  Caseless matching was not working for non-ASCII characters in back
953        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
954        It now works when Unicode Property Support is available.
956    5.  In pcretest, an escape such as \x{de} in the data was always generating
957        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
958        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
959        truncation.
961    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
963    7.  Added two (int) casts to pcregrep when printing the difference of two
964        pointers, in case they are 64-bit values.
966    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
967        test 2 if it fails.
969    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
970        and a #define of that name to empty if it is not externally set. This is to
971        allow users of MSVC to set it if necessary.
973    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
974        the convenience functions in the pcre_get.c source file.
976    11. An option change at the start of a pattern that had top-level alternatives
977        could cause overwriting and/or a crash. This command provoked a crash in
978        some environments:
980          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
982        This potential security problem was recorded as CVE-2008-2371.
984    12. For a pattern where the match had to start at the beginning or immediately
985        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
986        pcre_dfa_exec() could read past the end of the passed subject if there was
987        no match. To help with detecting such bugs (e.g. with valgrind), I modified
988        pcretest so that it places the subject at the end of its malloc-ed buffer.
990    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
991        exec() might read past the end of the data buffer in UTF-8 mode.
993    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
994        the data contained the byte 0x85 as part of a UTF-8 character within its
995        first line. This applied both to normal and DFA matching.
997    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
998        /^[^d]*?$/8 failed to match "abc".
1000    16. Added a missing copyright notice to pcrecpp_internal.h.
1002    17. Make it more clear in the documentation that values returned from
1003        pcre_exec() in ovector are byte offsets, not character counts.
1005    18. Tidied a few places to stop certain compilers from issuing warnings.
1007    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1008        supplied by Stefan Weber. I made a further small update for 7.8 because
1009        there is a change of source arrangements: the pcre_searchfuncs.c module is
1010        replaced by pcre_ucd.c.
1013    Version 7.7 07-May-08
1014    ---------------------
1016    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1017        a string to a long long, pretend we don't even have a long long." This is
1018        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1020    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1021        pre-7.6 versions, which defined a global no_arg variable instead of putting
1022        it in the RE class. (See also #8 below.)
1024    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1025        Lopes.
1027    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1029        (1) The include/exclude patterns were being applied to the whole pathnames
1030            of files, instead of just to the final components.
1032        (2) If there was more than one level of directory, the subdirectories were
1033            skipped unless they satisfied the include/exclude conditions. This is
1034            inconsistent with GNU grep (and could even be seen as contrary to the
1035            pcregrep specification - which I improved to make it absolutely clear).
1036            The action now is always to scan all levels of directory, and just
1037            apply the include/exclude patterns to regular files.
1039    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1040        --exclude_dir in the tests to avoid scanning .svn directories.
1042    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1043        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1044        doesn't support NULs in patterns.
1046    7.  Added some missing "const"s to declarations of static tables in
1047        pcre_compile.c and pcre_dfa_exec.c.
1049    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1050        caused by fix #2  above. (Subsequently also a second patch to fix the
1051        first patch. And a third patch - this was a messy problem.)
1053    9.  Applied Craig's patch to remove the use of push_back().
1055    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1056        matching function regexec().
1058    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1059        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1060        references. PCRE supports relative numbers with this syntax (I don't think
1061        Oniguruma does).
1063    12. Previously, a group with a zero repeat such as (...){0} was completely
1064        omitted from the compiled regex. However, this means that if the group
1065        was called as a subroutine from elsewhere in the pattern, things went wrong
1066        (an internal error was given). Such groups are now left in the compiled
1067        pattern, with a new opcode that causes them to be skipped at execution
1068        time.
1070    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1071        to the way PCRE behaves:
1073        (a) A lone ] character is dis-allowed (Perl treats it as data).
1075        (b) A back reference to an unmatched subpattern matches an empty string
1076            (Perl fails the current match path).
1078        (c) A data ] in a character class must be notated as \] because if the
1079            first data character in a class is ], it defines an empty class. (In
1080            Perl it is not possible to have an empty class.) The empty class []
1081            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1082            The negative empty class [^] matches any one character, independently
1083            of the DOTALL setting.
1085    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1086        non-existent subpattern following a character class starting with ']' and
1087        containing () gave an internal compiling error instead of "reference to
1088        non-existent subpattern". Fortunately, when the pattern did exist, the
1089        compiled code was correct. (When scanning forwards to check for the
1090        existencd of the subpattern, it was treating the data ']' as terminating
1091        the class, so got the count wrong. When actually compiling, the reference
1092        was subsequently set up correctly.)
1094    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1095        it was being rejected as not supported by pcre_dfa_exec(), even though
1096        other assertions are supported. I have made pcre_dfa_exec() support
1097        (*FAIL).
1099    16. The implementation of 13c above involved the invention of a new opcode,
1100        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1101        cannot be changed at match time, I realized I could make a small
1102        improvement to matching performance by compiling OP_ALLANY instead of
1103        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1104        on the OP_ANY path.
1106    17. Compiling pcretest on Windows with readline support failed without the
1107        following two fixes: (1) Make the unistd.h include conditional on
1108        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1110    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1111        ncurses library to be included for pcretest when ReadLine support is
1112        requested, but also to allow for it to be overridden. This patch came from
1113        Daniel Bergström.
1115    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1116        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1117        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1118        spotting this.
1121    Version 7.6 28-Jan-08
1122    ---------------------
1124    1.  A character class containing a very large number of characters with
1125        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1126        overflow.
1128    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1129        HAVE_LONG_LONG is not defined.
1131    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1132        bring them up to date and include new features. This patch includes:
1134        - Fixed PH's badly added libz and libbz2 support.
1135        - Fixed a problem with static linking.
1136        - Added pcredemo. [But later removed - see 7 below.]
1137        - Fixed dftables problem and added an option.
1138        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1139            HAVE_LONG_LONG.
1140        - Added readline support for pcretest.
1141        - Added an listing of the option settings after cmake has run.
1143    4.  A user submitted a patch to Makefile that makes it easy to create
1144        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1145        Makefile.am that cause it to include this special target, without
1146        affecting anything else. Note that the same mingw target plus all
1147        the other distribution libraries and programs are now supported
1148        when configuring with CMake (see 6 below) instead of with
1149        Configure/Make.
1151    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1152        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1153        exported in the Windows port". It has not yet been confirmed that the patch
1154        solves the problem, but it does no harm.
1156    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1157        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1158        with CMake, and also correct the comment about stack recursion.
1160    7.  Remove the automatic building of pcredemo from the ./configure system and
1161        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1162        of a program that users should build themselves after PCRE is installed, so
1163        building it automatically is not really right. What is more, it gave
1164        trouble in some build environments.
1166    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1169    Version 7.5 10-Jan-08
1170    ---------------------
1172    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1173        values in parens when parsing an RE using the C++ wrapper."
1175    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1176        Characters greater than 255 were excluded from the class instead of being
1177        included.
1179    3.  The same bug as (2) above applied to negated POSIX classes such as
1180        [:^space:].
1182    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1183        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1184        I have changed it.
1186    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1187        first named subpattern) and a construct such as (?&a) would reference the
1188        first named subpattern whose name started with "a" (in other words, the
1189        length check was missing). Both these problems are fixed. "Subpattern name
1190        expected" is now given for (?&) (a zero-length name), and this patch also
1191        makes it give the same error for \k'' (previously it complained that that
1192        was a reference to a non-existent subpattern).
1194    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1195        this is right because (?- can be followed by option settings as well as by
1196        digits. I have, however, made the messages clearer.
1198    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1199        than the number used in the conditional) now cause a compile-time error.
1200        This is actually not compatible with Perl, which accepts such patterns, but
1201        treats the conditional as always being FALSE (as PCRE used to), but it
1202        seems to me that giving a diagnostic is better.
1204    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1205        and messages.
1207    9.  Fix two occurrences of "backslash" in comments that should have been
1208        "backspace".
1210    10. Remove two redundant lines of code that can never be obeyed (their function
1211        was moved elsewhere).
1213    11. The program that makes PCRE's Unicode character property table had a bug
1214        which caused it to generate incorrect table entries for sequences of
1215        characters that have the same character type, but are in different scripts.
1216        It amalgamated them into a single range, with the script of the first of
1217        them. In other words, some characters were in the wrong script. There were
1218        thirteen such cases, affecting characters in the following ranges:
1220          U+002b0 - U+002c1
1221          U+0060c - U+0060d
1222          U+0061e - U+00612
1223          U+0064b - U+0065e
1224          U+0074d - U+0076d
1225          U+01800 - U+01805
1226          U+01d00 - U+01d77
1227          U+01d9b - U+01dbf
1228          U+0200b - U+0200f
1229          U+030fc - U+030fe
1230          U+03260 - U+0327f
1231          U+0fb46 - U+0fbb1
1232          U+10450 - U+1049d
1234    12. The -o option (show only the matching part of a line) for pcregrep was not
1235        compatible with GNU grep in that, if there was more than one match in a
1236        line, it showed only the first of them. It now behaves in the same way as
1237        GNU grep.
1239    13. If the -o and -v options were combined for pcregrep, it printed a blank
1240        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1241        does the same. The return code can be used to tell if there were any
1242        non-matching lines.
1244    14. Added --file-offsets and --line-offsets to pcregrep.
1246    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1247        infinitely looping recursion. The bug was that positive lookaheads were not
1248        being skipped when checking for a possible empty match (negative lookaheads
1249        and both kinds of lookbehind were skipped).
1251    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1252        inclusion of <windows.h> to before rather than after the definition of
1253        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1255    17. Specifying a possessive quantifier with a specific limit for a Unicode
1256        character property caused pcre_compile() to compile bad code, which led at
1257        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1258        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1259        caused the error; without that there was no problem.
1261    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1263    19. Added --enable-pcretest-libreadline.
1265    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1266        RE::GlobalReplace(). As a result, the number of replacements returned was
1267        double what it should be. I removed one of the increments, but Craig sent a
1268        later patch that removed the other one (the right fix) and added unit tests
1269        that check the return values (which was not done before).
1271    21. Several CMake things:
1273        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1274            the names libpcre and libpcreposix, not just pcre and pcreposix.
1276        (2) The above change means that pcretest and pcregrep are now correctly
1277            linked with the newly-built libraries, not previously installed ones.
1281    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1282        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1283        UTF-8 newline character). The key issue is that the pattern starts .*;
1284        this means that the match must be either at the beginning, or after a
1285        newline. The bug was in the code for advancing after a failed match and
1286        checking that the new position followed a newline. It was not taking
1287        account of UTF-8 characters correctly.
1289    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1290        character classes. PCRE was not treating the sequence [:...:] as a
1291        character class unless the ... were all letters. Perl, however, seems to
1292        allow any characters between [: and :], though of course it rejects as
1293        unknown any "names" that contain non-letters, because all the known class
1294        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1295        for example, whereas PCRE did not - it did not recognize a POSIX character
1296        class. This seemed a bit dangerous, so the code has been changed to be
1297        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1298        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1299        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1300        Perl does, and where it didn't before.
1302    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1303        Windows environments %n is disabled by default.
1306    Version 7.4 21-Sep-07
1307    ---------------------
1309    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1310        means that a class such as [\s] counted as "explicit reference to CR or
1311        LF". That isn't really right - the whole point of the change was to try to
1312        help when there was an actual mention of one of the two characters. So now
1313        the change happens only if \r or \n (or a literal CR or LF) character is
1314        encountered.
1316    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1317        of both had grown to the point where there were only 3 bits left.
1318        Fortunately, there was spare space in the data structure, and so I have
1319        moved the internal flags into a new 16-bit field to free up more option
1320        bits.
1322    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1323        but did not set the internal JCHANGED flag - either of these is enough to
1324        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1325        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1326        start sets both bits.
1328    4.  Added options (at build time, compile time, exec time) to change \R from
1329        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1331    5.  doc/pcresyntax.html was missing from the distribution.
1333    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1334        compatibility, even though it is no longer used.
1336    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1337        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1338        windows.h file is present (where different names are used). [This was
1339        reversed later after testing - see 16 below.]
1341    8.  Changed all #include <config.h> to #include "config.h". There were also
1342        some further <pcre.h> cases that I changed to "pcre.h".
1344    9.  When pcregrep was used with the --colour option, it missed the line ending
1345        sequence off the lines that it output.
1347    10. It was pointed out to me that arrays of string pointers cause lots of
1348        relocations when a shared library is dynamically loaded. A technique of
1349        using a single long string with a table of offsets can drastically reduce
1350        these. I have refactored PCRE in four places to do this. The result is
1351        dramatic:
1353          Originally:                          290
1354          After changing UCP table:            187
1355          After changing error message table:   43
1356          After changing table of "verbs"       36
1357          After changing table of Posix names   22
1359        Thanks to the folks working on Gregex for glib for this insight.
1361    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1362        unicode-properties was also set.
1364    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1366    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1367        checked only for CRLF.
1369    14. Added casts to pcretest.c to avoid compiler warnings.
1371    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1373    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1374        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1375        entirely. This removes changes made in 7 above.
1377    17. The CMake files have been updated, and there is now more information about
1378        building with CMake in the NON-UNIX-USE document.
1381    Version 7.3 28-Aug-07
1382  ---------------------  ---------------------
1384   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 64  Version 7.3 05-Jul-07 Line 1441  Version 7.3 05-Jul-07
1441      dynamic way, which I have now done. The artificial limitation on group      dynamic way, which I have now done. The artificial limitation on group
1442      length has been removed - we now have only the limit on the total length of      length has been removed - we now have only the limit on the total length of
1443      the compiled pattern, which depends on the LINK_SIZE setting.      the compiled pattern, which depends on the LINK_SIZE setting.
1445  10. Fixed a bug in the documentation for get/copy named substring when  10. Fixed a bug in the documentation for get/copy named substring when
1446      duplicate names are permitted. If none of the named substrings are set, the      duplicate names are permitted. If none of the named substrings are set, the
1447      functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an      functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1448      empty string.      empty string.
1450  11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E  11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1451      instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,      instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1452      because the ] is interpreted as the first data character and the      because the ] is interpreted as the first data character and the
1453      terminating ] is not found. PCRE has been made compatible with Perl in this      terminating ] is not found. PCRE has been made compatible with Perl in this
1454      regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could      regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1455      cause memory overwriting.      cause memory overwriting.
1457    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1458        string has been matched (to stop an infinite loop). It was not recognizing
1459        a conditional subpattern that could match an empty string if that
1460        subpattern was within another subpattern. For example, it looped when
1461        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1462        condition was not nested. This bug has been fixed.
1464    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1465        past the start of the subject in the presence of bytes with the top bit
1466        set, for example "\x8aBCD".
1468    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1469        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1471    14. Optimized (?!) to (*FAIL).
1473    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1474        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1475        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1476        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1477        does: it's just the validity check that is more restrictive.
1479    16. Inserted checks for integer overflows during escape sequence (backslash)
1480        processing, and also fixed erroneous offset values for syntax errors during
1481        backslash processing.
1483    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1484        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1486    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1487        caused an overrun.
1489    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1490        something other than just ASCII characters) inside a group that had an
1491        unlimited repeat caused a loop at compile time (while checking to see
1492        whether the group could match an empty string).
1494    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1495        [\P{Any}] did so. (Error in the code for printing property names.)
1497    21. An orphan \E inside a character class could cause a crash.
1499    22. A repeated capturing bracket such as (A)? could cause a wild memory
1500        reference during compilation.
1502    23. There are several functions in pcre_compile() that scan along a compiled
1503        expression for various reasons (e.g. to see if it's fixed length for look
1504        behind). There were bugs in these functions when a repeated \p or \P was
1505        present in the pattern. These operators have additional parameters compared
1506        with \d, etc, and these were not being taken into account when moving along
1507        the compiled data. Specifically:
1509        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1510            length.
1512        (b) An item such as \pL+ within a repeated group could cause crashes or
1513            loops.
1515        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1516            "reference to non-existent subpattern" error.
1518        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1520    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1521        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1523    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1525    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1526        character were causing crashes (broken optimization).
1528    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1529        \p or \P) caused a compile-time loop.
1531    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1532        break. For example, the unstudied pattern [\r\n]A does not match the string
1533        "\r\nA" because change 7.0/46 below moves the current point on by two
1534        characters after failing to match at the start. However, the pattern \nA
1535        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1536        the same is true. There doesn't seem any very clean way out of this, but
1537        what I have chosen to do makes the common cases work: PCRE now takes note
1538        of whether there can be an explicit match for \r or \n anywhere in the
1539        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1540        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1541        pattern has explicit CR or LF references.
1543    29. Added (*CR) etc for changing newline setting at start of pattern.
1546  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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