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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.00 ??-???-??  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.
142    Version 8.12 15-Jan-2011
143    ------------------------
145    1.  Fixed some typos in the markup of the man pages, and wrote a script that
146        checks for such things as part of the documentation building process.
148    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
149        --match-limit and --recursion-limit options (added for 8.11). In
150        particular, this made one of the standard tests fail. (The integer value
151        went into the wrong half of a long int.)
153    3.  If the --colour option was given to pcregrep with -v (invert match), it
154        did strange things, either producing crazy output, or crashing. It should,
155        of course, ignore a request for colour when reporting lines that do not
156        match.
158    4.  Another pcregrep bug caused similar problems if --colour was specified with
159        -M (multiline) and the pattern match finished with a line ending.
161    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
162        matched in multiline mode, the following line was shown as part of the
163        match. This seems wrong, so I have changed it.
165    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
166        the check for further matches in the same line (so they could be coloured)
167        to overrun the end of the current line. If another match was found, it was
168        incorrectly shown (and then shown again when found in the next line).
170    7.  If pcregrep was compiled under Windows, there was a reference to the
171        function pcregrep_exit() before it was defined. I am assuming this was
172        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
173        reported by a user. I've moved the definition above the reference.
176    Version 8.11 10-Dec-2010
177    ------------------------
179    1.  (*THEN) was not working properly if there were untried alternatives prior
180        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
181        backtracked to try for "b" instead of moving to the next alternative branch
182        at the same level (in this case, to look for "c"). The Perl documentation
183        is clear that when (*THEN) is backtracked onto, it goes to the "next
184        alternative in the innermost enclosing group".
186    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
187        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
188        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
189        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
190        (*THEN).
192    3.  If \s appeared in a character class, it removed the VT character from
193        the class, even if it had been included by some previous item, for example
194        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
195        of \s, but is part of the POSIX "space" class.)
197    4.  A partial match never returns an empty string (because you can always
198        match an empty string at the end of the subject); however the checking for
199        an empty string was starting at the "start of match" point. This has been
200        changed to the "earliest inspected character" point, because the returned
201        data for a partial match starts at this character. This means that, for
202        example, /(?<=abc)def/ gives a partial match for the subject "abc"
203        (previously it gave "no match").
205    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
206        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
207        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
208        has an implication that the given string is incomplete (because a partial
209        match is preferred over a full match). For this reason, these items now
210        give a partial match in this situation. [Aside: previously, the one case
211        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
212        match rather than a full match, which was wrong by the old rules, but is
213        now correct.]
215    6.  There was a bug in the handling of #-introduced comments, recognized when
216        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
217        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
218        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
219        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
220        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
221        places in pcre_compile().
223    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
224        comments when looking ahead for named forward references to subpatterns,
225        the only newline sequence it recognized was NL. It now handles newlines
226        according to the set newline convention.
228    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
229        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
230        cater for a lack of strerror(). These oversights have been fixed.
232    9.  Added --match-limit and --recursion-limit to pcregrep.
234    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
236    11. When the -o option was used, pcregrep was setting a return code of 1, even
237        when matches were found, and --line-buffered was not being honoured.
239    12. Added an optional parentheses number to the -o and --only-matching options
240        of pcregrep.
242    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
243        can match an empty string. The code to do it in pcretest and pcredemo
244        needed fixing:
246        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
247            only one byte after an empty string match just before CRLF (this case
248            just got forgotten; "any" and "anycrlf" were OK).
250        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
251            mode when an empty string match preceded an ASCII character followed by
252            a non-ASCII character. (The code for advancing by one character rather
253            than one byte was nonsense.)
255        (c) The pcredemo.c sample program did not have any code at all to handle
256            the cases when CRLF is a valid newline sequence.
258    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
259        as a starting offset was within the subject string. There is now a new
260        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
261        negative or greater than the length of the string. In order to test this,
262        pcretest is extended to allow the setting of negative starting offsets.
264    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
265        starting offset points to the beginning of a UTF-8 character was
266        unnecessarily clumsy. I tidied it up.
268    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
269        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
271    17. Nobody had reported that the --include_dir option, which was added in
272        release 7.7 should have been called --include-dir (hyphen, not underscore)
273        for compatibility with GNU grep. I have changed it to --include-dir, but
274        left --include_dir as an undocumented synonym, and the same for
275        --exclude-dir, though that is not available in GNU grep, at least as of
276        release 2.5.4.
278    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
279        characters from a string of bytes) have been redefined so as not to use
280        loops, in order to improve performance in some environments. At the same
281        time, I abstracted some of the common code into auxiliary macros to save
282        repetition (this should not affect the compiled code).
284    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
285        compile-time error is now given if \c is not followed by an ASCII
286        character, that is, a byte less than 128. (In EBCDIC mode, the code is
287        different, and any byte value is allowed.)
289    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
290        START_OPTIMIZE option, which is now allowed at compile time - but just
291        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
292        to pcregrep and other applications that have no direct access to PCRE
293        options. The new /Y option in pcretest sets this option when calling
294        pcre_compile().
296    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
297        back references. Groups containing recursive back references were forced to
298        be atomic by that change, but in the case of named groups, the amount of
299        memory required was incorrectly computed, leading to "Failed: internal
300        error: code overflow". This has been fixed.
302    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
303        pcretest.c, to avoid build problems in some Borland environments.
306    Version 8.10 25-Jun-2010
307    ------------------------
309    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
310        THEN.
312    2.  (*ACCEPT) was not working when inside an atomic group.
314    3.  Inside a character class, \B is treated as a literal by default, but
315        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
316        causes the error). The code is unchanged, but I tidied the documentation.
318    4.  Inside a character class, PCRE always treated \R and \X as literals,
319        whereas Perl faults them if its -w option is set. I have changed PCRE so
320        that it faults them when PCRE_EXTRA is set.
322    5.  Added support for \N, which always matches any character other than
323        newline. (It is the same as "." when PCRE_DOTALL is not set.)
325    6.  When compiling pcregrep with newer versions of gcc which may have
326        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
327        declared with attribute warn_unused_result" were given. Just casting the
328        result to (void) does not stop the warnings; a more elaborate fudge is
329        needed. I've used a macro to implement this.
331    7.  Minor change to pcretest.c to avoid a compiler warning.
333    8.  Added four artifical Unicode properties to help with an option to make
334        \s etc use properties (see next item). The new properties are: Xan
335        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
337    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
338        use Unicode properties. (*UCP) at the start of a pattern can be used to set
339        this option. Modified pcretest to add /W to test this facility. Added
340        REG_UCP to make it available via the POSIX interface.
342    10. Added --line-buffered to pcregrep.
344    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
345        studied, and the match started with a letter with a code point greater than
346        127 whose first byte was different to the first byte of the other case of
347        the letter, the other case of this starting letter was not recognized
348        (#976).
350    12. If a pattern that was studied started with a repeated Unicode property
351        test, for example, \p{Nd}+, there was the theoretical possibility of
352        setting up an incorrect bitmap of starting bytes, but fortunately it could
353        not have actually happened in practice until change 8 above was made (it
354        added property types that matched character-matching opcodes).
356    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
357        possible starting bytes for non-anchored patterns.
359    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
360        \R, and also a number of cases that involve Unicode properties, both
361        explicit and implicit when PCRE_UCP is set.
363    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
364        input, it could crash or give wrong results if characters with values
365        greater than 0xc0 were present in the subject string. (Detail: it assumed
366        UTF-8 input when processing these items.)
368    16. Added a lot of (int) casts to avoid compiler warnings in systems where
369        size_t is 64-bit (#991).
371    17. Added a check for running out of memory when PCRE is compiled with
372        --disable-stack-for-recursion (#990).
374    18. If the last data line in a file for pcretest does not have a newline on
375        the end, a newline was missing in the output.
377    19. The default pcre_chartables.c file recognizes only ASCII characters (values
378        less than 128) in its various bitmaps. However, there is a facility for
379        generating tables according to the current locale when PCRE is compiled. It
380        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
381        characters, are recognized by isspace() and therefore were getting set in
382        these tables, and indeed these tables seem to approximate to ISO 8859. This
383        caused a problem in UTF-8 mode when pcre_study() was used to create a list
384        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
385        which of course cannot start UTF-8 characters. I have changed the code so
386        that only real ASCII characters (less than 128) and the correct starting
387        bytes for UTF-8 encodings are set for characters greater than 127 when in
388        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
389        altogether.)
391    20. Added the /T option to pcretest so as to be able to run tests with non-
392        standard character tables, thus making it possible to include the tests
393        used for 19 above in the standard set of tests.
395    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
396        reference to a subpattern the other side of a comment that contains an
397        opening parenthesis caused either an internal compiling error, or a
398        reference to the wrong subpattern.
401    Version 8.02 19-Mar-2010
402    ------------------------
404    1.  The Unicode data tables have been updated to Unicode 5.2.0.
406    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
407        configured.
409    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
410        original author of that file, following a query about its status.
412    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
413        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
415    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
416        quantifier applied to a forward-referencing subroutine call, could compile
417        incorrect code or give the error "internal error: previously-checked
418        referenced subpattern not found".
420    6.  Both MS Visual Studio and Symbian OS have problems with initializing
421        variables to point to external functions. For these systems, therefore,
422        pcre_malloc etc. are now initialized to local functions that call the
423        relevant global functions.
425    7.  There were two entries missing in the vectors called coptable and poptable
426        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
427        I've fixed the data, and added a kludgy way of testing at compile time that
428        the lengths are correct (equal to the number of opcodes).
430    8.  Following on from 7, I added a similar kludge to check the length of the
431        eint vector in pcreposix.c.
433    9.  Error texts for pcre_compile() are held as one long string to avoid too
434        much relocation at load time. To find a text, the string is searched,
435        counting zeros. There was no check for running off the end of the string,
436        which could happen if a new error number was added without updating the
437        string.
439    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
441    11. \K was not working if it appeared in an atomic group or in a group that
442        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
443        \K is "not well defined" if used in an assertion. PCRE now accepts it if
444        the assertion is positive, but not if it is negative.
446    12. Change 11 fortuitously reduced the size of the stack frame used in the
447        "match()" function of pcre_exec.c by one pointer. Forthcoming
448        implementation of support for (*MARK) will need an extra pointer on the
449        stack; I have reserved it now, so that the stack frame size does not
450        decrease.
452    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
453        item in branch that calls a recursion is a subroutine call - as in the
454        second branch in the above example - was incorrectly given the compile-
455        time error "recursive call could loop indefinitely" because pcre_compile()
456        was not correctly checking the subroutine for matching a non-empty string.
458    14. The checks for overrunning compiling workspace could trigger after an
459        overrun had occurred. This is a "should never occur" error, but it can be
460        triggered by pathological patterns such as hundreds of nested parentheses.
461        The checks now trigger 100 bytes before the end of the workspace.
463    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
466    Version 8.01 19-Jan-2010
467    ------------------------
469    1.  If a pattern contained a conditional subpattern with only one branch (in
470        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
471        computed the wrong minimum data length (which is of course zero for such
472        subpatterns). This could cause incorrect "no match" results.
474    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
475        the pattern is reset in the first branch, pcre_compile() failed with
476        "internal error: code overflow at offset...". This happened only when
477        the reset was to the original external option setting. (An optimization
478        abstracts leading options settings into an external setting, which was the
479        cause of this.)
481    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
482        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
483        assertion pattern did not match (meaning that the assertion was true), it
484        was incorrectly treated as false if the SKIP had been reached during the
485        matching. This also applied to assertions used as conditions.
487    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
488        assertion subpattern, including such a pattern used as a condition,
489        unpredictable results occurred, instead of the error return
492    5.  The C++ GlobalReplace function was not working like Perl for the special
493        situation when an empty string is matched. It now does the fancy magic
494        stuff that is necessary.
496    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
497        removed. (These were left over from very, very early versions of PCRE.)
499    7.  Some cosmetic changes to the code to make life easier when compiling it
500        as part of something else:
502        (a) Change DEBUG to PCRE_DEBUG.
504        (b) In pcre_compile(), rename the member of the "branch_chain" structure
505            called "current" as "current_branch", to prevent a collision with the
506            Linux macro when compiled as a kernel module.
508        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
509            prevent a collision with the Linux macro when compiled as a kernel
510            module.
512    8.  In pcre_compile() there are some checks for integer overflows that used to
513        cast potentially large values to (double). This has been changed to that
514        when building, a check for int64_t is made, and if it is found, it is used
515        instead, thus avoiding the use of floating point arithmetic. (There is no
516        other use of FP in PCRE.) If int64_t is not found, the fallback is to
517        double.
519    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
520        2005 (difference between two addresses compared to an unsigned value).
522    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
523        custom one, because of the following reported problem in Windows:
525          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
526              under Win32.
527          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
528              therefore missing the function definition.
529          - The compiler thus generates a "C" signature for the test function.
530          - The linker fails to find the "C" function.
531          - PCRE fails to configure if asked to do so against libbz2.
533    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
534        messages were output:
536          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
537          rerunning libtoolize, to keep the correct libtool macros in-tree.
538          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
540        I have done both of these things.
542    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
543        most of the time, it *can* run out if it is given a pattern that contains a
544        runaway infinite recursion. I updated the discussion in the pcrestack man
545        page.
547    13. Now that we have gone to the x.xx style of version numbers, the minor
548        version may start with zero. Using 08 or 09 is a bad idea because users
549        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
550        interpreted as invalid octal numbers. I've updated the previous comment in
551        configure.ac, and also added a check that gives an error if 08 or 09 are
552        used.
554    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
555        causing partial matching to fail when the end of the subject matched \W
556        in a UTF-8 pattern where \W was quantified with a minimum of 3.
558    15. There were some discrepancies between the declarations in pcre_internal.h
559        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
560        their definitions. The declarations used "const uschar *" and the
561        definitions used USPTR. Even though USPTR is normally defined as "const
562        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
563        reported that: "This difference in casting confuses some C++ compilers, for
564        example, SunCC recognizes above declarations as different functions and
565        generates broken code for hbpcre." I have changed the declarations to use
566        USPTR.
568    16. GNU libtool is named differently on some systems. The autogen.sh script now
569        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
570        (FreeBSD).
572    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
573        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
574        comment: "Figure out how to create a longlong from a string: strtoll and
575        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
576        instance, but it only takes 2 args instead of 3!"
578    18. A subtle bug concerned with back references has been fixed by a change of
579        specification, with a corresponding code fix. A pattern such as
580        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
581        refers, was giving matches when it shouldn't. For example, xa=xaaa would
582        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
583        same bug. Such groups have to be quantified to be useful, or contained
584        inside another quantified group. (If there's no repetition, the reference
585        can never match.) The problem arises because, having left the group and
586        moved on to the rest of the pattern, a later failure that backtracks into
587        the group uses the captured value from the final iteration of the group
588        rather than the correct earlier one. I have fixed this in PCRE by forcing
589        any group that contains a reference to itself to be an atomic group; that
590        is, there cannot be any backtracking into it once it has completed. This is
591        similar to recursive and subroutine calls.
594    Version 8.00 19-Oct-09
595  ----------------------  ----------------------
597  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
598      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
599      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
600      error.      error.
602  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
603      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
604      in a Windows environment.      in a Windows environment.
606  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
607      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
608      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
609      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
610      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
611      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
612      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
614  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
615      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
616      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
617      the old behaviour.      the old behaviour.
619  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
620      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
621      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
622      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
624    6.  No libpcreposix.pc file was created for pkg-config; there was just
625        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
627    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
628        when UCP support is not needed, by modifying the Python script that
629        generates it from Unicode data files. This should not matter if the module
630        is correctly used as a library, but I received one complaint about 50K of
631        unwanted data. My guess is that the person linked everything into his
632        program rather than using a library. Anyway, it does no harm.
634    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
635        was a minimum greater than 1 for a wide character in a possessive
636        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
637        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
638        character. Chaos in the form of incorrect output or a compiling loop could
639        result.
641    9.  The restrictions on what a pattern can contain when partial matching is
642        requested for pcre_exec() have been removed. All patterns can now be
643        partially matched by this function. In addition, if there are at least two
644        slots in the offset vector, the offset of the earliest inspected character
645        for the match and the offset of the end of the subject are set in them when
646        PCRE_ERROR_PARTIAL is returned.
648    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
649        synonymous with PCRE_PARTIAL, for backwards compatibility, and
650        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
651        and may be more useful for multi-segment matching.
653    11. Partial matching with pcre_exec() is now more intuitive. A partial match
654        used to be given if ever the end of the subject was reached; now it is
655        given only if matching could not proceed because another character was
656        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
657        string "Z", which now yields "no match" instead of "partial match". In the
658        case of pcre_dfa_exec(), "no match" is given if every matching path for the
659        final character ended with (*FAIL).
661    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
662        if the pattern had a "must contain" character that was already found in the
663        earlier partial match, unless partial matching was again requested. For
664        example, with the pattern /dog.(body)?/, the "must contain" character is
665        "g". If the first part-match was for the string "dog", restarting with
666        "sbody" failed. This bug has been fixed.
668    13. The string returned by pcre_dfa_exec() after a partial match has been
669        changed so that it starts at the first inspected character rather than the
670        first character of the match. This makes a difference only if the pattern
671        starts with a lookbehind assertion or \b or \B (\K is not supported by
672        pcre_dfa_exec()). It's an incompatible change, but it makes the two
673        matching functions compatible, and I think it's the right thing to do.
675    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
676        so that the demonstration program is easily available in environments where
677        PCRE has not been installed from source.
679    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
680        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
681        library.
683    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
684        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
685        is not the first non-POSIX option to be added. Clearly some people find
686        these options useful.
688    17. If a caller to the POSIX matching function regexec() passes a non-zero
689        value for nmatch with a NULL value for pmatch, the value of
690        nmatch is forced to zero.
692    18. RunGrepTest did not have a test for the availability of the -u option of
693        the diff command, as RunTest does. It now checks in the same way as
694        RunTest, and also checks for the -b option.
696    19. If an odd number of negated classes containing just a single character
697        interposed, within parentheses, between a forward reference to a named
698        subpattern and the definition of the subpattern, compilation crashed with
699        an internal error, complaining that it could not find the referenced
700        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
701        [The bug was that it was starting one character too far in when skipping
702        over the character class, thus treating the ] as data rather than
703        terminating the class. This meant it could skip too much.]
705    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
706        /g option in pcretest when the pattern contains \K, which makes it possible
707        to have an empty string match not at the start, even when the pattern is
708        anchored. Updated pcretest and pcredemo to use this option.
710    21. If the maximum number of capturing subpatterns in a recursion was greater
711        than the maximum at the outer level, the higher number was returned, but
712        with unset values at the outer level. The correct (outer level) value is
713        now given.
715    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
716        PCRE did not set those parentheses (unlike Perl). I have now found a way to
717        make it do so. The string so far is captured, making this feature
718        compatible with Perl.
720    23. The tests have been re-organized, adding tests 11 and 12, to make it
721        possible to check the Perl 5.10 features against Perl 5.10.
723    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
724        pattern matches a fixed length string. PCRE did not allow this; now it
725        does. Neither allows recursion.
727    25. I finally figured out how to implement a request to provide the minimum
728        length of subject string that was needed in order to match a given pattern.
729        (It was back references and recursion that I had previously got hung up
730        on.) This code has now been added to pcre_study(); it finds a lower bound
731        to the length of subject needed. It is not necessarily the greatest lower
732        bound, but using it to avoid searching strings that are too short does give
733        some useful speed-ups. The value is available to calling programs via
734        pcre_fullinfo().
736    26. While implementing 25, I discovered to my embarrassment that pcretest had
737        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
738        study optimizations had never been tested with that matching function.
739        Oops. What is worse, even when it was passed study data, there was a bug in
740        pcre_dfa_exec() that meant it never actually used it. Double oops. There
741        were also very few tests of studied patterns with pcre_dfa_exec().
743    27. If (?| is used to create subpatterns with duplicate numbers, they are now
744        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
745        on the other side of the coin, they are no longer allowed to have different
746        names, because these cannot be distinguished in PCRE, and this has caused
747        confusion. (This is a difference from Perl.)
749    28. When duplicate subpattern names are present (necessarily with different
750        numbers, as required by 27 above), and a test is made by name in a
751        conditional pattern, either for a subpattern having been matched, or for
752        recursion in such a pattern, all the associated numbered subpatterns are
753        tested, and the overall condition is true if the condition is true for any
754        one of them. This is the way Perl works, and is also more like the way
755        testing by number works.
758  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
759  ---------------------  ---------------------

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