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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.
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).
196    38. Add minix to OS list not supporting the -S option in pcretest.
198    39. PCRE tries to detect cases of infinite recursion at compile time, but it
199        cannot analyze patterns in sufficient detail to catch mutual recursions
200        such as ((?1))((?2)). There is now a runtime test that gives an error if a
201        subgroup is called recursively as a subpattern for a second time at the
202        same position in the subject string. In previous releases this might have
203        been caught by the recursion limit, or it might have run out of stack.
205    40. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
206        happen only once. PCRE was, however incorrectly giving a compile time error
207        "recursive call could loop indefinitely" because it cannot analyze the
208        pattern in sufficient detail. The compile time test no longer happens when
209        PCRE is compiling a conditional subpattern, but actual runaway loops are
210        now caught at runtime (see 39 above).
212    41. It seems that Perl allows any characters other than a closing parenthesis
213        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
214        has been changed to be the same.
217    Version 8.12 15-Jan-2011
218    ------------------------
220    1.  Fixed some typos in the markup of the man pages, and wrote a script that
221        checks for such things as part of the documentation building process.
223    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
224        --match-limit and --recursion-limit options (added for 8.11). In
225        particular, this made one of the standard tests fail. (The integer value
226        went into the wrong half of a long int.)
228    3.  If the --colour option was given to pcregrep with -v (invert match), it
229        did strange things, either producing crazy output, or crashing. It should,
230        of course, ignore a request for colour when reporting lines that do not
231        match.
233    4.  Another pcregrep bug caused similar problems if --colour was specified with
234        -M (multiline) and the pattern match finished with a line ending.
236    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
237        matched in multiline mode, the following line was shown as part of the
238        match. This seems wrong, so I have changed it.
240    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
241        the check for further matches in the same line (so they could be coloured)
242        to overrun the end of the current line. If another match was found, it was
243        incorrectly shown (and then shown again when found in the next line).
245    7.  If pcregrep was compiled under Windows, there was a reference to the
246        function pcregrep_exit() before it was defined. I am assuming this was
247        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
248        reported by a user. I've moved the definition above the reference.
251    Version 8.11 10-Dec-2010
252    ------------------------
254    1.  (*THEN) was not working properly if there were untried alternatives prior
255        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
256        backtracked to try for "b" instead of moving to the next alternative branch
257        at the same level (in this case, to look for "c"). The Perl documentation
258        is clear that when (*THEN) is backtracked onto, it goes to the "next
259        alternative in the innermost enclosing group".
261    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
262        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
263        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
264        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
265        (*THEN).
267    3.  If \s appeared in a character class, it removed the VT character from
268        the class, even if it had been included by some previous item, for example
269        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
270        of \s, but is part of the POSIX "space" class.)
272    4.  A partial match never returns an empty string (because you can always
273        match an empty string at the end of the subject); however the checking for
274        an empty string was starting at the "start of match" point. This has been
275        changed to the "earliest inspected character" point, because the returned
276        data for a partial match starts at this character. This means that, for
277        example, /(?<=abc)def/ gives a partial match for the subject "abc"
278        (previously it gave "no match").
280    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
281        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
282        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
283        has an implication that the given string is incomplete (because a partial
284        match is preferred over a full match). For this reason, these items now
285        give a partial match in this situation. [Aside: previously, the one case
286        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
287        match rather than a full match, which was wrong by the old rules, but is
288        now correct.]
290    6.  There was a bug in the handling of #-introduced comments, recognized when
291        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
292        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
293        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
294        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
295        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
296        places in pcre_compile().
298    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
299        comments when looking ahead for named forward references to subpatterns,
300        the only newline sequence it recognized was NL. It now handles newlines
301        according to the set newline convention.
303    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
304        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
305        cater for a lack of strerror(). These oversights have been fixed.
307    9.  Added --match-limit and --recursion-limit to pcregrep.
309    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
311    11. When the -o option was used, pcregrep was setting a return code of 1, even
312        when matches were found, and --line-buffered was not being honoured.
314    12. Added an optional parentheses number to the -o and --only-matching options
315        of pcregrep.
317    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
318        can match an empty string. The code to do it in pcretest and pcredemo
319        needed fixing:
321        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
322            only one byte after an empty string match just before CRLF (this case
323            just got forgotten; "any" and "anycrlf" were OK).
325        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
326            mode when an empty string match preceded an ASCII character followed by
327            a non-ASCII character. (The code for advancing by one character rather
328            than one byte was nonsense.)
330        (c) The pcredemo.c sample program did not have any code at all to handle
331            the cases when CRLF is a valid newline sequence.
333    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
334        as a starting offset was within the subject string. There is now a new
335        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
336        negative or greater than the length of the string. In order to test this,
337        pcretest is extended to allow the setting of negative starting offsets.
339    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
340        starting offset points to the beginning of a UTF-8 character was
341        unnecessarily clumsy. I tidied it up.
343    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
344        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
346    17. Nobody had reported that the --include_dir option, which was added in
347        release 7.7 should have been called --include-dir (hyphen, not underscore)
348        for compatibility with GNU grep. I have changed it to --include-dir, but
349        left --include_dir as an undocumented synonym, and the same for
350        --exclude-dir, though that is not available in GNU grep, at least as of
351        release 2.5.4.
353    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
354        characters from a string of bytes) have been redefined so as not to use
355        loops, in order to improve performance in some environments. At the same
356        time, I abstracted some of the common code into auxiliary macros to save
357        repetition (this should not affect the compiled code).
359    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
360        compile-time error is now given if \c is not followed by an ASCII
361        character, that is, a byte less than 128. (In EBCDIC mode, the code is
362        different, and any byte value is allowed.)
364    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
365        START_OPTIMIZE option, which is now allowed at compile time - but just
366        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
367        to pcregrep and other applications that have no direct access to PCRE
368        options. The new /Y option in pcretest sets this option when calling
369        pcre_compile().
371    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
372        back references. Groups containing recursive back references were forced to
373        be atomic by that change, but in the case of named groups, the amount of
374        memory required was incorrectly computed, leading to "Failed: internal
375        error: code overflow". This has been fixed.
377    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
378        pcretest.c, to avoid build problems in some Borland environments.
381    Version 8.10 25-Jun-2010
382    ------------------------
384    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
385        THEN.
387    2.  (*ACCEPT) was not working when inside an atomic group.
389    3.  Inside a character class, \B is treated as a literal by default, but
390        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
391        causes the error). The code is unchanged, but I tidied the documentation.
393    4.  Inside a character class, PCRE always treated \R and \X as literals,
394        whereas Perl faults them if its -w option is set. I have changed PCRE so
395        that it faults them when PCRE_EXTRA is set.
397    5.  Added support for \N, which always matches any character other than
398        newline. (It is the same as "." when PCRE_DOTALL is not set.)
400    6.  When compiling pcregrep with newer versions of gcc which may have
401        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
402        declared with attribute warn_unused_result" were given. Just casting the
403        result to (void) does not stop the warnings; a more elaborate fudge is
404        needed. I've used a macro to implement this.
406    7.  Minor change to pcretest.c to avoid a compiler warning.
408    8.  Added four artifical Unicode properties to help with an option to make
409        \s etc use properties (see next item). The new properties are: Xan
410        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
412    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
413        use Unicode properties. (*UCP) at the start of a pattern can be used to set
414        this option. Modified pcretest to add /W to test this facility. Added
415        REG_UCP to make it available via the POSIX interface.
417    10. Added --line-buffered to pcregrep.
419    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
420        studied, and the match started with a letter with a code point greater than
421        127 whose first byte was different to the first byte of the other case of
422        the letter, the other case of this starting letter was not recognized
423        (#976).
425    12. If a pattern that was studied started with a repeated Unicode property
426        test, for example, \p{Nd}+, there was the theoretical possibility of
427        setting up an incorrect bitmap of starting bytes, but fortunately it could
428        not have actually happened in practice until change 8 above was made (it
429        added property types that matched character-matching opcodes).
431    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
432        possible starting bytes for non-anchored patterns.
434    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
435        \R, and also a number of cases that involve Unicode properties, both
436        explicit and implicit when PCRE_UCP is set.
438    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
439        input, it could crash or give wrong results if characters with values
440        greater than 0xc0 were present in the subject string. (Detail: it assumed
441        UTF-8 input when processing these items.)
443    16. Added a lot of (int) casts to avoid compiler warnings in systems where
444        size_t is 64-bit (#991).
446    17. Added a check for running out of memory when PCRE is compiled with
447        --disable-stack-for-recursion (#990).
449    18. If the last data line in a file for pcretest does not have a newline on
450        the end, a newline was missing in the output.
452    19. The default pcre_chartables.c file recognizes only ASCII characters (values
453        less than 128) in its various bitmaps. However, there is a facility for
454        generating tables according to the current locale when PCRE is compiled. It
455        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
456        characters, are recognized by isspace() and therefore were getting set in
457        these tables, and indeed these tables seem to approximate to ISO 8859. This
458        caused a problem in UTF-8 mode when pcre_study() was used to create a list
459        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
460        which of course cannot start UTF-8 characters. I have changed the code so
461        that only real ASCII characters (less than 128) and the correct starting
462        bytes for UTF-8 encodings are set for characters greater than 127 when in
463        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
464        altogether.)
466    20. Added the /T option to pcretest so as to be able to run tests with non-
467        standard character tables, thus making it possible to include the tests
468        used for 19 above in the standard set of tests.
470    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
471        reference to a subpattern the other side of a comment that contains an
472        opening parenthesis caused either an internal compiling error, or a
473        reference to the wrong subpattern.
476    Version 8.02 19-Mar-2010
477    ------------------------
479    1.  The Unicode data tables have been updated to Unicode 5.2.0.
481    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
482        configured.
484    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
485        original author of that file, following a query about its status.
487    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
488        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
490    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
491        quantifier applied to a forward-referencing subroutine call, could compile
492        incorrect code or give the error "internal error: previously-checked
493        referenced subpattern not found".
495    6.  Both MS Visual Studio and Symbian OS have problems with initializing
496        variables to point to external functions. For these systems, therefore,
497        pcre_malloc etc. are now initialized to local functions that call the
498        relevant global functions.
500    7.  There were two entries missing in the vectors called coptable and poptable
501        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
502        I've fixed the data, and added a kludgy way of testing at compile time that
503        the lengths are correct (equal to the number of opcodes).
505    8.  Following on from 7, I added a similar kludge to check the length of the
506        eint vector in pcreposix.c.
508    9.  Error texts for pcre_compile() are held as one long string to avoid too
509        much relocation at load time. To find a text, the string is searched,
510        counting zeros. There was no check for running off the end of the string,
511        which could happen if a new error number was added without updating the
512        string.
514    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
516    11. \K was not working if it appeared in an atomic group or in a group that
517        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
518        \K is "not well defined" if used in an assertion. PCRE now accepts it if
519        the assertion is positive, but not if it is negative.
521    12. Change 11 fortuitously reduced the size of the stack frame used in the
522        "match()" function of pcre_exec.c by one pointer. Forthcoming
523        implementation of support for (*MARK) will need an extra pointer on the
524        stack; I have reserved it now, so that the stack frame size does not
525        decrease.
527    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
528        item in branch that calls a recursion is a subroutine call - as in the
529        second branch in the above example - was incorrectly given the compile-
530        time error "recursive call could loop indefinitely" because pcre_compile()
531        was not correctly checking the subroutine for matching a non-empty string.
533    14. The checks for overrunning compiling workspace could trigger after an
534        overrun had occurred. This is a "should never occur" error, but it can be
535        triggered by pathological patterns such as hundreds of nested parentheses.
536        The checks now trigger 100 bytes before the end of the workspace.
538    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
541    Version 8.01 19-Jan-2010
542    ------------------------
544    1.  If a pattern contained a conditional subpattern with only one branch (in
545        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
546        computed the wrong minimum data length (which is of course zero for such
547        subpatterns). This could cause incorrect "no match" results.
549    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
550        the pattern is reset in the first branch, pcre_compile() failed with
551        "internal error: code overflow at offset...". This happened only when
552        the reset was to the original external option setting. (An optimization
553        abstracts leading options settings into an external setting, which was the
554        cause of this.)
556    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
557        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
558        assertion pattern did not match (meaning that the assertion was true), it
559        was incorrectly treated as false if the SKIP had been reached during the
560        matching. This also applied to assertions used as conditions.
562    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
563        assertion subpattern, including such a pattern used as a condition,
564        unpredictable results occurred, instead of the error return
567    5.  The C++ GlobalReplace function was not working like Perl for the special
568        situation when an empty string is matched. It now does the fancy magic
569        stuff that is necessary.
571    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
572        removed. (These were left over from very, very early versions of PCRE.)
574    7.  Some cosmetic changes to the code to make life easier when compiling it
575        as part of something else:
577        (a) Change DEBUG to PCRE_DEBUG.
579        (b) In pcre_compile(), rename the member of the "branch_chain" structure
580            called "current" as "current_branch", to prevent a collision with the
581            Linux macro when compiled as a kernel module.
583        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
584            prevent a collision with the Linux macro when compiled as a kernel
585            module.
587    8.  In pcre_compile() there are some checks for integer overflows that used to
588        cast potentially large values to (double). This has been changed to that
589        when building, a check for int64_t is made, and if it is found, it is used
590        instead, thus avoiding the use of floating point arithmetic. (There is no
591        other use of FP in PCRE.) If int64_t is not found, the fallback is to
592        double.
594    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
595        2005 (difference between two addresses compared to an unsigned value).
597    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
598        custom one, because of the following reported problem in Windows:
600          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
601              under Win32.
602          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
603              therefore missing the function definition.
604          - The compiler thus generates a "C" signature for the test function.
605          - The linker fails to find the "C" function.
606          - PCRE fails to configure if asked to do so against libbz2.
608    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
609        messages were output:
611          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
612          rerunning libtoolize, to keep the correct libtool macros in-tree.
613          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
615        I have done both of these things.
617    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
618        most of the time, it *can* run out if it is given a pattern that contains a
619        runaway infinite recursion. I updated the discussion in the pcrestack man
620        page.
622    13. Now that we have gone to the x.xx style of version numbers, the minor
623        version may start with zero. Using 08 or 09 is a bad idea because users
624        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
625        interpreted as invalid octal numbers. I've updated the previous comment in
626        configure.ac, and also added a check that gives an error if 08 or 09 are
627        used.
629    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
630        causing partial matching to fail when the end of the subject matched \W
631        in a UTF-8 pattern where \W was quantified with a minimum of 3.
633    15. There were some discrepancies between the declarations in pcre_internal.h
634        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
635        their definitions. The declarations used "const uschar *" and the
636        definitions used USPTR. Even though USPTR is normally defined as "const
637        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
638        reported that: "This difference in casting confuses some C++ compilers, for
639        example, SunCC recognizes above declarations as different functions and
640        generates broken code for hbpcre." I have changed the declarations to use
641        USPTR.
643    16. GNU libtool is named differently on some systems. The autogen.sh script now
644        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
645        (FreeBSD).
647    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
648        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
649        comment: "Figure out how to create a longlong from a string: strtoll and
650        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
651        instance, but it only takes 2 args instead of 3!"
653    18. A subtle bug concerned with back references has been fixed by a change of
654        specification, with a corresponding code fix. A pattern such as
655        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
656        refers, was giving matches when it shouldn't. For example, xa=xaaa would
657        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
658        same bug. Such groups have to be quantified to be useful, or contained
659        inside another quantified group. (If there's no repetition, the reference
660        can never match.) The problem arises because, having left the group and
661        moved on to the rest of the pattern, a later failure that backtracks into
662        the group uses the captured value from the final iteration of the group
663        rather than the correct earlier one. I have fixed this in PCRE by forcing
664        any group that contains a reference to itself to be an atomic group; that
665        is, there cannot be any backtracking into it once it has completed. This is
666        similar to recursive and subroutine calls.
669    Version 8.00 19-Oct-09
670  ----------------------  ----------------------
672  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
673      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
674      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
675      error.      error.
677    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
678        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
679        in a Windows environment.
681    3.  The pcregrep --count option prints the count for each file even when it is
682        zero, as does GNU grep. However, pcregrep was also printing all files when
683        --files-with-matches was added. Now, when both options are given, it prints
684        counts only for those files that have at least one match. (GNU grep just
685        prints the file name in this circumstance, but including the count seems
686        more useful - otherwise, why use --count?) Also ensured that the
687        combination -clh just lists non-zero counts, with no names.
689    4.  The long form of the pcregrep -F option was incorrectly implemented as
690        --fixed_strings instead of --fixed-strings. This is an incompatible change,
691        but it seems right to fix it, and I didn't think it was worth preserving
692        the old behaviour.
694    5.  The command line items --regex=pattern and --regexp=pattern were not
695        recognized by pcregrep, which required --regex pattern or --regexp pattern
696        (with a space rather than an '='). The man page documented the '=' forms,
697        which are compatible with GNU grep; these now work.
699    6.  No libpcreposix.pc file was created for pkg-config; there was just
700        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
702    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
703        when UCP support is not needed, by modifying the Python script that
704        generates it from Unicode data files. This should not matter if the module
705        is correctly used as a library, but I received one complaint about 50K of
706        unwanted data. My guess is that the person linked everything into his
707        program rather than using a library. Anyway, it does no harm.
709    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
710        was a minimum greater than 1 for a wide character in a possessive
711        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
712        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
713        character. Chaos in the form of incorrect output or a compiling loop could
714        result.
716    9.  The restrictions on what a pattern can contain when partial matching is
717        requested for pcre_exec() have been removed. All patterns can now be
718        partially matched by this function. In addition, if there are at least two
719        slots in the offset vector, the offset of the earliest inspected character
720        for the match and the offset of the end of the subject are set in them when
721        PCRE_ERROR_PARTIAL is returned.
723    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
724        synonymous with PCRE_PARTIAL, for backwards compatibility, and
725        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
726        and may be more useful for multi-segment matching.
728    11. Partial matching with pcre_exec() is now more intuitive. A partial match
729        used to be given if ever the end of the subject was reached; now it is
730        given only if matching could not proceed because another character was
731        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
732        string "Z", which now yields "no match" instead of "partial match". In the
733        case of pcre_dfa_exec(), "no match" is given if every matching path for the
734        final character ended with (*FAIL).
736    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
737        if the pattern had a "must contain" character that was already found in the
738        earlier partial match, unless partial matching was again requested. For
739        example, with the pattern /dog.(body)?/, the "must contain" character is
740        "g". If the first part-match was for the string "dog", restarting with
741        "sbody" failed. This bug has been fixed.
743    13. The string returned by pcre_dfa_exec() after a partial match has been
744        changed so that it starts at the first inspected character rather than the
745        first character of the match. This makes a difference only if the pattern
746        starts with a lookbehind assertion or \b or \B (\K is not supported by
747        pcre_dfa_exec()). It's an incompatible change, but it makes the two
748        matching functions compatible, and I think it's the right thing to do.
750    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
751        so that the demonstration program is easily available in environments where
752        PCRE has not been installed from source.
754    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
755        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
756        library.
758    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
759        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
760        is not the first non-POSIX option to be added. Clearly some people find
761        these options useful.
763    17. If a caller to the POSIX matching function regexec() passes a non-zero
764        value for nmatch with a NULL value for pmatch, the value of
765        nmatch is forced to zero.
767    18. RunGrepTest did not have a test for the availability of the -u option of
768        the diff command, as RunTest does. It now checks in the same way as
769        RunTest, and also checks for the -b option.
771    19. If an odd number of negated classes containing just a single character
772        interposed, within parentheses, between a forward reference to a named
773        subpattern and the definition of the subpattern, compilation crashed with
774        an internal error, complaining that it could not find the referenced
775        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
776        [The bug was that it was starting one character too far in when skipping
777        over the character class, thus treating the ] as data rather than
778        terminating the class. This meant it could skip too much.]
780    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
781        /g option in pcretest when the pattern contains \K, which makes it possible
782        to have an empty string match not at the start, even when the pattern is
783        anchored. Updated pcretest and pcredemo to use this option.
785    21. If the maximum number of capturing subpatterns in a recursion was greater
786        than the maximum at the outer level, the higher number was returned, but
787        with unset values at the outer level. The correct (outer level) value is
788        now given.
790    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
791        PCRE did not set those parentheses (unlike Perl). I have now found a way to
792        make it do so. The string so far is captured, making this feature
793        compatible with Perl.
795    23. The tests have been re-organized, adding tests 11 and 12, to make it
796        possible to check the Perl 5.10 features against Perl 5.10.
798    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
799        pattern matches a fixed length string. PCRE did not allow this; now it
800        does. Neither allows recursion.
802    25. I finally figured out how to implement a request to provide the minimum
803        length of subject string that was needed in order to match a given pattern.
804        (It was back references and recursion that I had previously got hung up
805        on.) This code has now been added to pcre_study(); it finds a lower bound
806        to the length of subject needed. It is not necessarily the greatest lower
807        bound, but using it to avoid searching strings that are too short does give
808        some useful speed-ups. The value is available to calling programs via
809        pcre_fullinfo().
811    26. While implementing 25, I discovered to my embarrassment that pcretest had
812        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
813        study optimizations had never been tested with that matching function.
814        Oops. What is worse, even when it was passed study data, there was a bug in
815        pcre_dfa_exec() that meant it never actually used it. Double oops. There
816        were also very few tests of studied patterns with pcre_dfa_exec().
818    27. If (?| is used to create subpatterns with duplicate numbers, they are now
819        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
820        on the other side of the coin, they are no longer allowed to have different
821        names, because these cannot be distinguished in PCRE, and this has caused
822        confusion. (This is a difference from Perl.)
824    28. When duplicate subpattern names are present (necessarily with different
825        numbers, as required by 27 above), and a test is made by name in a
826        conditional pattern, either for a subpattern having been matched, or for
827        recursion in such a pattern, all the associated numbered subpatterns are
828        tested, and the overall condition is true if the condition is true for any
829        one of them. This is the way Perl works, and is also more like the way
830        testing by number works.
833  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
834  ---------------------  ---------------------

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