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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
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).
14    
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).
23    
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.
28    
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().
34    
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.
38    
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.
46    
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.
55    
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().
59    
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
62    
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.
68    
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.
72    
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.
77    
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).
86    
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.
90    
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.
95    
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.
102    
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.
106    
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
109    
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.
113    
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.
116    
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.
125    
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).
129    
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.
136    
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.
140    
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.
147    
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.
151    
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.
154    
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
157    
158    
159    
160    Version 8.12 15-Jan-2011
161    ------------------------
162    
163    1.  Fixed some typos in the markup of the man pages, and wrote a script that
164        checks for such things as part of the documentation building process.
165    
166    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
167        --match-limit and --recursion-limit options (added for 8.11). In
168        particular, this made one of the standard tests fail. (The integer value
169        went into the wrong half of a long int.)
170    
171    3.  If the --colour option was given to pcregrep with -v (invert match), it
172        did strange things, either producing crazy output, or crashing. It should,
173        of course, ignore a request for colour when reporting lines that do not
174        match.
175    
176    4.  Another pcregrep bug caused similar problems if --colour was specified with
177        -M (multiline) and the pattern match finished with a line ending.
178    
179    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
180        matched in multiline mode, the following line was shown as part of the
181        match. This seems wrong, so I have changed it.
182    
183    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
184        the check for further matches in the same line (so they could be coloured)
185        to overrun the end of the current line. If another match was found, it was
186        incorrectly shown (and then shown again when found in the next line).
187    
188    7.  If pcregrep was compiled under Windows, there was a reference to the
189        function pcregrep_exit() before it was defined. I am assuming this was
190        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
191        reported by a user. I've moved the definition above the reference.
192    
193    
194    Version 8.11 10-Dec-2010
195    ------------------------
196    
197    1.  (*THEN) was not working properly if there were untried alternatives prior
198        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
199        backtracked to try for "b" instead of moving to the next alternative branch
200        at the same level (in this case, to look for "c"). The Perl documentation
201        is clear that when (*THEN) is backtracked onto, it goes to the "next
202        alternative in the innermost enclosing group".
203    
204    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
205        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
206        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
207        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
208        (*THEN).
209    
210    3.  If \s appeared in a character class, it removed the VT character from
211        the class, even if it had been included by some previous item, for example
212        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
213        of \s, but is part of the POSIX "space" class.)
214    
215    4.  A partial match never returns an empty string (because you can always
216        match an empty string at the end of the subject); however the checking for
217        an empty string was starting at the "start of match" point. This has been
218        changed to the "earliest inspected character" point, because the returned
219        data for a partial match starts at this character. This means that, for
220        example, /(?<=abc)def/ gives a partial match for the subject "abc"
221        (previously it gave "no match").
222    
223    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
224        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
225        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
226        has an implication that the given string is incomplete (because a partial
227        match is preferred over a full match). For this reason, these items now
228        give a partial match in this situation. [Aside: previously, the one case
229        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
230        match rather than a full match, which was wrong by the old rules, but is
231        now correct.]
232    
233    6.  There was a bug in the handling of #-introduced comments, recognized when
234        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
235        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
236        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
237        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
238        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
239        places in pcre_compile().
240    
241    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
242        comments when looking ahead for named forward references to subpatterns,
243        the only newline sequence it recognized was NL. It now handles newlines
244        according to the set newline convention.
245    
246    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
247        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
248        cater for a lack of strerror(). These oversights have been fixed.
249    
250    9.  Added --match-limit and --recursion-limit to pcregrep.
251    
252    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
253    
254    11. When the -o option was used, pcregrep was setting a return code of 1, even
255        when matches were found, and --line-buffered was not being honoured.
256    
257    12. Added an optional parentheses number to the -o and --only-matching options
258        of pcregrep.
259    
260    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
261        can match an empty string. The code to do it in pcretest and pcredemo
262        needed fixing:
263    
264        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
265            only one byte after an empty string match just before CRLF (this case
266            just got forgotten; "any" and "anycrlf" were OK).
267    
268        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
269            mode when an empty string match preceded an ASCII character followed by
270            a non-ASCII character. (The code for advancing by one character rather
271            than one byte was nonsense.)
272    
273        (c) The pcredemo.c sample program did not have any code at all to handle
274            the cases when CRLF is a valid newline sequence.
275    
276    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
277        as a starting offset was within the subject string. There is now a new
278        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
279        negative or greater than the length of the string. In order to test this,
280        pcretest is extended to allow the setting of negative starting offsets.
281    
282    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
283        starting offset points to the beginning of a UTF-8 character was
284        unnecessarily clumsy. I tidied it up.
285    
286    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
287        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
288    
289    17. Nobody had reported that the --include_dir option, which was added in
290        release 7.7 should have been called --include-dir (hyphen, not underscore)
291        for compatibility with GNU grep. I have changed it to --include-dir, but
292        left --include_dir as an undocumented synonym, and the same for
293        --exclude-dir, though that is not available in GNU grep, at least as of
294        release 2.5.4.
295    
296    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
297        characters from a string of bytes) have been redefined so as not to use
298        loops, in order to improve performance in some environments. At the same
299        time, I abstracted some of the common code into auxiliary macros to save
300        repetition (this should not affect the compiled code).
301    
302    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
303        compile-time error is now given if \c is not followed by an ASCII
304        character, that is, a byte less than 128. (In EBCDIC mode, the code is
305        different, and any byte value is allowed.)
306    
307    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
308        START_OPTIMIZE option, which is now allowed at compile time - but just
309        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
310        to pcregrep and other applications that have no direct access to PCRE
311        options. The new /Y option in pcretest sets this option when calling
312        pcre_compile().
313    
314    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
315        back references. Groups containing recursive back references were forced to
316        be atomic by that change, but in the case of named groups, the amount of
317        memory required was incorrectly computed, leading to "Failed: internal
318        error: code overflow". This has been fixed.
319    
320    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
321        pcretest.c, to avoid build problems in some Borland environments.
322    
323    
324    Version 8.10 25-Jun-2010
325    ------------------------
326    
327    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
328        THEN.
329    
330    2.  (*ACCEPT) was not working when inside an atomic group.
331    
332    3.  Inside a character class, \B is treated as a literal by default, but
333        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
334        causes the error). The code is unchanged, but I tidied the documentation.
335    
336    4.  Inside a character class, PCRE always treated \R and \X as literals,
337        whereas Perl faults them if its -w option is set. I have changed PCRE so
338        that it faults them when PCRE_EXTRA is set.
339    
340    5.  Added support for \N, which always matches any character other than
341        newline. (It is the same as "." when PCRE_DOTALL is not set.)
342    
343    6.  When compiling pcregrep with newer versions of gcc which may have
344        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
345        declared with attribute warn_unused_result" were given. Just casting the
346        result to (void) does not stop the warnings; a more elaborate fudge is
347        needed. I've used a macro to implement this.
348    
349    7.  Minor change to pcretest.c to avoid a compiler warning.
350    
351    8.  Added four artifical Unicode properties to help with an option to make
352        \s etc use properties (see next item). The new properties are: Xan
353        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
354    
355    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
356        use Unicode properties. (*UCP) at the start of a pattern can be used to set
357        this option. Modified pcretest to add /W to test this facility. Added
358        REG_UCP to make it available via the POSIX interface.
359    
360    10. Added --line-buffered to pcregrep.
361    
362    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
363        studied, and the match started with a letter with a code point greater than
364        127 whose first byte was different to the first byte of the other case of
365        the letter, the other case of this starting letter was not recognized
366        (#976).
367    
368    12. If a pattern that was studied started with a repeated Unicode property
369        test, for example, \p{Nd}+, there was the theoretical possibility of
370        setting up an incorrect bitmap of starting bytes, but fortunately it could
371        not have actually happened in practice until change 8 above was made (it
372        added property types that matched character-matching opcodes).
373    
374    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
375        possible starting bytes for non-anchored patterns.
376    
377    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
378        \R, and also a number of cases that involve Unicode properties, both
379        explicit and implicit when PCRE_UCP is set.
380    
381    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
382        input, it could crash or give wrong results if characters with values
383        greater than 0xc0 were present in the subject string. (Detail: it assumed
384        UTF-8 input when processing these items.)
385    
386    16. Added a lot of (int) casts to avoid compiler warnings in systems where
387        size_t is 64-bit (#991).
388    
389    17. Added a check for running out of memory when PCRE is compiled with
390        --disable-stack-for-recursion (#990).
391    
392    18. If the last data line in a file for pcretest does not have a newline on
393        the end, a newline was missing in the output.
394    
395    19. The default pcre_chartables.c file recognizes only ASCII characters (values
396        less than 128) in its various bitmaps. However, there is a facility for
397        generating tables according to the current locale when PCRE is compiled. It
398        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
399        characters, are recognized by isspace() and therefore were getting set in
400        these tables, and indeed these tables seem to approximate to ISO 8859. This
401        caused a problem in UTF-8 mode when pcre_study() was used to create a list
402        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
403        which of course cannot start UTF-8 characters. I have changed the code so
404        that only real ASCII characters (less than 128) and the correct starting
405        bytes for UTF-8 encodings are set for characters greater than 127 when in
406        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
407        altogether.)
408    
409    20. Added the /T option to pcretest so as to be able to run tests with non-
410        standard character tables, thus making it possible to include the tests
411        used for 19 above in the standard set of tests.
412    
413    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
414        reference to a subpattern the other side of a comment that contains an
415        opening parenthesis caused either an internal compiling error, or a
416        reference to the wrong subpattern.
417    
418    
419    Version 8.02 19-Mar-2010
420    ------------------------
421    
422    1.  The Unicode data tables have been updated to Unicode 5.2.0.
423    
424    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
425        configured.
426    
427    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
428        original author of that file, following a query about its status.
429    
430    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
431        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
432    
433    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
434        quantifier applied to a forward-referencing subroutine call, could compile
435        incorrect code or give the error "internal error: previously-checked
436        referenced subpattern not found".
437    
438    6.  Both MS Visual Studio and Symbian OS have problems with initializing
439        variables to point to external functions. For these systems, therefore,
440        pcre_malloc etc. are now initialized to local functions that call the
441        relevant global functions.
442    
443    7.  There were two entries missing in the vectors called coptable and poptable
444        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
445        I've fixed the data, and added a kludgy way of testing at compile time that
446        the lengths are correct (equal to the number of opcodes).
447    
448    8.  Following on from 7, I added a similar kludge to check the length of the
449        eint vector in pcreposix.c.
450    
451    9.  Error texts for pcre_compile() are held as one long string to avoid too
452        much relocation at load time. To find a text, the string is searched,
453        counting zeros. There was no check for running off the end of the string,
454        which could happen if a new error number was added without updating the
455        string.
456    
457    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
458    
459    11. \K was not working if it appeared in an atomic group or in a group that
460        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
461        \K is "not well defined" if used in an assertion. PCRE now accepts it if
462        the assertion is positive, but not if it is negative.
463    
464    12. Change 11 fortuitously reduced the size of the stack frame used in the
465        "match()" function of pcre_exec.c by one pointer. Forthcoming
466        implementation of support for (*MARK) will need an extra pointer on the
467        stack; I have reserved it now, so that the stack frame size does not
468        decrease.
469    
470    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
471        item in branch that calls a recursion is a subroutine call - as in the
472        second branch in the above example - was incorrectly given the compile-
473        time error "recursive call could loop indefinitely" because pcre_compile()
474        was not correctly checking the subroutine for matching a non-empty string.
475    
476    14. The checks for overrunning compiling workspace could trigger after an
477        overrun had occurred. This is a "should never occur" error, but it can be
478        triggered by pathological patterns such as hundreds of nested parentheses.
479        The checks now trigger 100 bytes before the end of the workspace.
480    
481    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
482    
483    
484    Version 8.01 19-Jan-2010
485    ------------------------
486    
487    1.  If a pattern contained a conditional subpattern with only one branch (in
488        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
489        computed the wrong minimum data length (which is of course zero for such
490        subpatterns). This could cause incorrect "no match" results.
491    
492    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
493        the pattern is reset in the first branch, pcre_compile() failed with
494        "internal error: code overflow at offset...". This happened only when
495        the reset was to the original external option setting. (An optimization
496        abstracts leading options settings into an external setting, which was the
497        cause of this.)
498    
499    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
500        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
501        assertion pattern did not match (meaning that the assertion was true), it
502        was incorrectly treated as false if the SKIP had been reached during the
503        matching. This also applied to assertions used as conditions.
504    
505    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
506        assertion subpattern, including such a pattern used as a condition,
507        unpredictable results occurred, instead of the error return
508        PCRE_ERROR_DFA_UITEM.
509    
510    5.  The C++ GlobalReplace function was not working like Perl for the special
511        situation when an empty string is matched. It now does the fancy magic
512        stuff that is necessary.
513    
514    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
515        removed. (These were left over from very, very early versions of PCRE.)
516    
517    7.  Some cosmetic changes to the code to make life easier when compiling it
518        as part of something else:
519    
520        (a) Change DEBUG to PCRE_DEBUG.
521    
522        (b) In pcre_compile(), rename the member of the "branch_chain" structure
523            called "current" as "current_branch", to prevent a collision with the
524            Linux macro when compiled as a kernel module.
525    
526        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
527            prevent a collision with the Linux macro when compiled as a kernel
528            module.
529    
530    8.  In pcre_compile() there are some checks for integer overflows that used to
531        cast potentially large values to (double). This has been changed to that
532        when building, a check for int64_t is made, and if it is found, it is used
533        instead, thus avoiding the use of floating point arithmetic. (There is no
534        other use of FP in PCRE.) If int64_t is not found, the fallback is to
535        double.
536    
537    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
538        2005 (difference between two addresses compared to an unsigned value).
539    
540    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
541        custom one, because of the following reported problem in Windows:
542    
543          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
544              under Win32.
545          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
546              therefore missing the function definition.
547          - The compiler thus generates a "C" signature for the test function.
548          - The linker fails to find the "C" function.
549          - PCRE fails to configure if asked to do so against libbz2.
550    
551    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
552        messages were output:
553    
554          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
555          rerunning libtoolize, to keep the correct libtool macros in-tree.
556          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
557    
558        I have done both of these things.
559    
560    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
561        most of the time, it *can* run out if it is given a pattern that contains a
562        runaway infinite recursion. I updated the discussion in the pcrestack man
563        page.
564    
565    13. Now that we have gone to the x.xx style of version numbers, the minor
566        version may start with zero. Using 08 or 09 is a bad idea because users
567        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
568        interpreted as invalid octal numbers. I've updated the previous comment in
569        configure.ac, and also added a check that gives an error if 08 or 09 are
570        used.
571    
572    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
573        causing partial matching to fail when the end of the subject matched \W
574        in a UTF-8 pattern where \W was quantified with a minimum of 3.
575    
576    15. There were some discrepancies between the declarations in pcre_internal.h
577        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
578        their definitions. The declarations used "const uschar *" and the
579        definitions used USPTR. Even though USPTR is normally defined as "const
580        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
581        reported that: "This difference in casting confuses some C++ compilers, for
582        example, SunCC recognizes above declarations as different functions and
583        generates broken code for hbpcre." I have changed the declarations to use
584        USPTR.
585    
586    16. GNU libtool is named differently on some systems. The autogen.sh script now
587        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
588        (FreeBSD).
589    
590    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
591        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
592        comment: "Figure out how to create a longlong from a string: strtoll and
593        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
594        instance, but it only takes 2 args instead of 3!"
595    
596    18. A subtle bug concerned with back references has been fixed by a change of
597        specification, with a corresponding code fix. A pattern such as
598        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
599        refers, was giving matches when it shouldn't. For example, xa=xaaa would
600        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
601        same bug. Such groups have to be quantified to be useful, or contained
602        inside another quantified group. (If there's no repetition, the reference
603        can never match.) The problem arises because, having left the group and
604        moved on to the rest of the pattern, a later failure that backtracks into
605        the group uses the captured value from the final iteration of the group
606        rather than the correct earlier one. I have fixed this in PCRE by forcing
607        any group that contains a reference to itself to be an atomic group; that
608        is, there cannot be any backtracking into it once it has completed. This is
609        similar to recursive and subroutine calls.
610    
611    
612  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
613  ----------------------  ----------------------
614    

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