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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.9 xx-xxx-09  Version 8.20
5    ------------
7    1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8    a POSIX class. After further experiments with Perl, which convinced me that
9    Perl has bugs and confusions, a closing square bracket is no longer allowed in
10    a POSIX name.
13    Version 8.13 16-Aug-2011
14    ------------------------
16    1.  The Unicode data tables have been updated to Unicode 6.0.0.
18    2.  Two minor typos in pcre_internal.h have been fixed.
20    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
21        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
22        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
24    4.  There were a number of related bugs in the code for matching backrefences
25        caselessly in UTF-8 mode when codes for the characters concerned were
26        different numbers of bytes. For example, U+023A and U+2C65 are an upper
27        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
28        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
29        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
30        2-byte code at the end of the subject (it thought there wasn't enough data
31        left).
33    5.  Comprehensive information about what went wrong is now returned by
34        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
35        as the output vector has at least 2 elements. The offset of the start of
36        the failing character and a reason code are placed in the vector.
38    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
39        now returned is for the first byte of the failing character, instead of the
40        last byte inspected. This is an incompatible change, but I hope it is small
41        enough not to be a problem. It makes the returned offset consistent with
42        pcre_exec() and pcre_dfa_exec().
44    7.  pcretest now gives a text phrase as well as the error number when
45        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
46        failure, the offset and reason code are output.
48    8.  When \R was used with a maximizing quantifier it failed to skip backwards
49        over a \r\n pair if the subsequent match failed. Instead, it just skipped
50        back over a single character (\n). This seems wrong (because it treated the
51        two characters as a single entity when going forwards), conflicts with the
52        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
53        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
54        has been changed.
56    9.  Some internal refactoring has changed the processing so that the handling
57        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
58        time (the PCRE_DOTALL option was changed this way some time ago: version
59        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
60        which was always a bit of a fudge. It also means that there is one less
61        argument for the match() function, which reduces its stack requirements
62        slightly. This change also fixes an incompatibility with Perl: the pattern
63        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
65    10. More internal refactoring has drastically reduced the number of recursive
66        calls to match() for possessively repeated groups such as (abc)++ when
67        using pcre_exec().
69    11. While implementing 10, a number of bugs in the handling of groups were
70        discovered and fixed:
72        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
73        (a|)*(?1) gave a compile-time internal error.
74        ((a|)+)+  did not notice that the outer group could match an empty string.
75        (^a|^)+   was not marked as anchored.
76        (.*a|.*)+ was not marked as matching at start or after a newline.
78    12. Yet more internal refactoring has removed another argument from the match()
79        function. Special calls to this function are now indicated by setting a
80        value in a variable in the "match data" data block.
82    13. Be more explicit in pcre_study() instead of relying on "default" for
83        opcodes that mean there is no starting character; this means that when new
84        ones are added and accidentally left out of pcre_study(), testing should
85        pick them up.
87    14. The -s option of pcretest has been documented for ages as being an old
88        synonym of -m (show memory usage). I have changed it to mean "force study
89        for every regex", that is, assume /S for every regex. This is similar to -i
90        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
91        using it. It makes it easier to run collections of tests with and without
92        study enabled, and thereby test pcre_study() more easily. All the standard
93        tests are now run with and without -s (but some patterns can be marked as
94        "never study" - see 20 below).
96    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
97        restoration of the capturing data to the outer values was not happening
98        correctly.
100    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
101        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
102        pattern had matched an empty string, and so incorrectly returned a no
103        match.
105    17. There was optimizing code for the last branch of non-capturing parentheses,
106        and also for the obeyed branch of a conditional subexpression, which used
107        tail recursion to cut down on stack usage. Unfortunately, now that there is
108        the possibility of (*THEN) occurring in these branches, tail recursion is
109        no longer possible because the return has to be checked for (*THEN). These
110        two optimizations have therefore been removed.
112    18. If a pattern containing \R was studied, it was assumed that \R always
113        matched two bytes, thus causing the minimum subject length to be
114        incorrectly computed because \R can also match just one byte.
116    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
117        was incorrectly computed.
119    20. If /S is present twice on a test pattern in pcretest input, it now
120        *disables* studying, thereby overriding the use of -s on the command line
121        (see 14 above). This is necessary for one or two tests to keep the output
122        identical in both cases.
124    21. When (*ACCEPT) was used in an assertion that matched an empty string and
125        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
127    22. When an atomic group that contained a capturing parenthesis was
128        successfully matched, but the branch in which it appeared failed, the
129        capturing was not being forgotten if a higher numbered group was later
130        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
131        group 1 to "a", when in fact it should be unset. This applied to multi-
132        branched capturing and non-capturing groups, repeated or not, and also to
133        positive assertions (capturing in negative assertions does not happen
134        in PCRE) and also to nested atomic groups.
136    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
137        subject after a captured substring, to make it easier to tell which of a
138        number of identical substrings has been captured.
140    24. The way atomic groups are processed by pcre_exec() has been changed so that
141        if they are repeated, backtracking one repetition now resets captured
142        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
143        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
144        "aaa". Previously, it would have been "a". As part of this code
145        refactoring, the way recursive calls are handled has also been changed.
147    25. If an assertion condition captured any substrings, they were not passed
148        back unless some other capturing happened later. For example, if
149        (?(?=(a))a) was matched against "a", no capturing was returned.
151    26. When studying a pattern that contained subroutine calls or assertions,
152        the code for finding the minimum length of a possible match was handling
153        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
154        group 1 called group 2 while simultaneously a separate group 2 called group
155        1). A stack overflow occurred in this case. I have fixed this by limiting
156        the recursion depth to 10.
158    27. Updated RunTest.bat in the distribution to the version supplied by Tom
159        Fortmann. This supports explicit test numbers on the command line, and has
160        argument validation and error reporting.
162    28. An instance of \X with an unlimited repeat could fail if at any point the
163        first character it looked at was a mark character.
165    29. Some minor code refactoring concerning Unicode properties and scripts
166        should reduce the stack requirement of match() slightly.
168    30. Added the '=' option to pcretest to check the setting of unused capturing
169        slots at the end of the pattern, which are documented as being -1, but are
170        not included in the return count.
172    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
173        compiled something random. Now it gives a compile-time error (as does
174        Perl).
176    32. A *MARK encountered during the processing of a positive assertion is now
177        recorded and passed back (compatible with Perl).
179    33. If --only-matching or --colour was set on a pcregrep call whose pattern
180        had alternative anchored branches, the search for a second match in a line
181        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
182        matched the line "0102" twice. The same bug affected patterns that started
183        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
184        twice.
186    34. Previously, PCRE did not allow quantification of assertions. However, Perl
187        does, and because of capturing effects, quantifying parenthesized
188        assertions may at times be useful. Quantifiers are now allowed for
189        parenthesized assertions.
191    35. A minor code tidy in pcre_compile() when checking options for \R usage.
193    36. \g was being checked for fancy things in a character class, when it should
194        just be a literal "g".
196    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
197        appearance of a nested POSIX class supersedes an apparent external class.
198        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
199        unescaped square brackets may also appear as part of class names. For
200        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
201        more like Perl. (But see 8.20/1 above.)
203    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
204        was because it thought it was \N{name}, which is not supported).
206    39. Add minix to OS list not supporting the -S option in pcretest.
208    40. PCRE tries to detect cases of infinite recursion at compile time, but it
209        cannot analyze patterns in sufficient detail to catch mutual recursions
210        such as ((?1))((?2)). There is now a runtime test that gives an error if a
211        subgroup is called recursively as a subpattern for a second time at the
212        same position in the subject string. In previous releases this might have
213        been caught by the recursion limit, or it might have run out of stack.
215    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
216        happen only once. PCRE was, however incorrectly giving a compile time error
217        "recursive call could loop indefinitely" because it cannot analyze the
218        pattern in sufficient detail. The compile time test no longer happens when
219        PCRE is compiling a conditional subpattern, but actual runaway loops are
220        now caught at runtime (see 40 above).
222    42. It seems that Perl allows any characters other than a closing parenthesis
223        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
224        has been changed to be the same.
226    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
227        as not to get warnings when autogen.sh is called. Also changed
228        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
230    44. To help people who use pcregrep to scan files containing exceedingly long
231        lines, the following changes have been made:
233        (a) The default value of the buffer size parameter has been increased from
234            8K to 20K. (The actual buffer used is three times this size.)
236        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
237            PCRE is built.
239        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
240            to be set at run time.
242        (d) Numerical values in pcregrep options can be followed by K or M, for
243            example --buffer-size=50K.
245        (e) If a line being scanned overflows pcregrep's buffer, an error is now
246            given and the return code is set to 2.
248    45. Add a pointer to the latest mark to the callout data block.
250    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
251        partial match of an empty string instead of no match. This was specific to
252        the use of ".".
254    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
255        complete match instead of a partial match. This bug was dependent on both
256        the PCRE_UTF8 and PCRE_DOTALL options being set.
258    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
259        starting byte set, because \b was not being ignored.
262    Version 8.12 15-Jan-2011
263    ------------------------
265    1.  Fixed some typos in the markup of the man pages, and wrote a script that
266        checks for such things as part of the documentation building process.
268    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
269        --match-limit and --recursion-limit options (added for 8.11). In
270        particular, this made one of the standard tests fail. (The integer value
271        went into the wrong half of a long int.)
273    3.  If the --colour option was given to pcregrep with -v (invert match), it
274        did strange things, either producing crazy output, or crashing. It should,
275        of course, ignore a request for colour when reporting lines that do not
276        match.
278    4.  Another pcregrep bug caused similar problems if --colour was specified with
279        -M (multiline) and the pattern match finished with a line ending.
281    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
282        matched in multiline mode, the following line was shown as part of the
283        match. This seems wrong, so I have changed it.
285    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
286        the check for further matches in the same line (so they could be coloured)
287        to overrun the end of the current line. If another match was found, it was
288        incorrectly shown (and then shown again when found in the next line).
290    7.  If pcregrep was compiled under Windows, there was a reference to the
291        function pcregrep_exit() before it was defined. I am assuming this was
292        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
293        reported by a user. I've moved the definition above the reference.
296    Version 8.11 10-Dec-2010
297    ------------------------
299    1.  (*THEN) was not working properly if there were untried alternatives prior
300        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
301        backtracked to try for "b" instead of moving to the next alternative branch
302        at the same level (in this case, to look for "c"). The Perl documentation
303        is clear that when (*THEN) is backtracked onto, it goes to the "next
304        alternative in the innermost enclosing group".
306    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
307        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
308        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
309        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
310        (*THEN).
312    3.  If \s appeared in a character class, it removed the VT character from
313        the class, even if it had been included by some previous item, for example
314        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
315        of \s, but is part of the POSIX "space" class.)
317    4.  A partial match never returns an empty string (because you can always
318        match an empty string at the end of the subject); however the checking for
319        an empty string was starting at the "start of match" point. This has been
320        changed to the "earliest inspected character" point, because the returned
321        data for a partial match starts at this character. This means that, for
322        example, /(?<=abc)def/ gives a partial match for the subject "abc"
323        (previously it gave "no match").
325    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
326        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
327        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
328        has an implication that the given string is incomplete (because a partial
329        match is preferred over a full match). For this reason, these items now
330        give a partial match in this situation. [Aside: previously, the one case
331        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
332        match rather than a full match, which was wrong by the old rules, but is
333        now correct.]
335    6.  There was a bug in the handling of #-introduced comments, recognized when
336        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
337        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
338        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
339        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
340        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
341        places in pcre_compile().
343    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
344        comments when looking ahead for named forward references to subpatterns,
345        the only newline sequence it recognized was NL. It now handles newlines
346        according to the set newline convention.
348    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
349        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
350        cater for a lack of strerror(). These oversights have been fixed.
352    9.  Added --match-limit and --recursion-limit to pcregrep.
354    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
356    11. When the -o option was used, pcregrep was setting a return code of 1, even
357        when matches were found, and --line-buffered was not being honoured.
359    12. Added an optional parentheses number to the -o and --only-matching options
360        of pcregrep.
362    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
363        can match an empty string. The code to do it in pcretest and pcredemo
364        needed fixing:
366        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
367            only one byte after an empty string match just before CRLF (this case
368            just got forgotten; "any" and "anycrlf" were OK).
370        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
371            mode when an empty string match preceded an ASCII character followed by
372            a non-ASCII character. (The code for advancing by one character rather
373            than one byte was nonsense.)
375        (c) The pcredemo.c sample program did not have any code at all to handle
376            the cases when CRLF is a valid newline sequence.
378    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
379        as a starting offset was within the subject string. There is now a new
380        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
381        negative or greater than the length of the string. In order to test this,
382        pcretest is extended to allow the setting of negative starting offsets.
384    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
385        starting offset points to the beginning of a UTF-8 character was
386        unnecessarily clumsy. I tidied it up.
388    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
389        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
391    17. Nobody had reported that the --include_dir option, which was added in
392        release 7.7 should have been called --include-dir (hyphen, not underscore)
393        for compatibility with GNU grep. I have changed it to --include-dir, but
394        left --include_dir as an undocumented synonym, and the same for
395        --exclude-dir, though that is not available in GNU grep, at least as of
396        release 2.5.4.
398    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
399        characters from a string of bytes) have been redefined so as not to use
400        loops, in order to improve performance in some environments. At the same
401        time, I abstracted some of the common code into auxiliary macros to save
402        repetition (this should not affect the compiled code).
404    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
405        compile-time error is now given if \c is not followed by an ASCII
406        character, that is, a byte less than 128. (In EBCDIC mode, the code is
407        different, and any byte value is allowed.)
409    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
410        START_OPTIMIZE option, which is now allowed at compile time - but just
411        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
412        to pcregrep and other applications that have no direct access to PCRE
413        options. The new /Y option in pcretest sets this option when calling
414        pcre_compile().
416    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
417        back references. Groups containing recursive back references were forced to
418        be atomic by that change, but in the case of named groups, the amount of
419        memory required was incorrectly computed, leading to "Failed: internal
420        error: code overflow". This has been fixed.
422    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
423        pcretest.c, to avoid build problems in some Borland environments.
426    Version 8.10 25-Jun-2010
427    ------------------------
429    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
430        THEN.
432    2.  (*ACCEPT) was not working when inside an atomic group.
434    3.  Inside a character class, \B is treated as a literal by default, but
435        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
436        causes the error). The code is unchanged, but I tidied the documentation.
438    4.  Inside a character class, PCRE always treated \R and \X as literals,
439        whereas Perl faults them if its -w option is set. I have changed PCRE so
440        that it faults them when PCRE_EXTRA is set.
442    5.  Added support for \N, which always matches any character other than
443        newline. (It is the same as "." when PCRE_DOTALL is not set.)
445    6.  When compiling pcregrep with newer versions of gcc which may have
446        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
447        declared with attribute warn_unused_result" were given. Just casting the
448        result to (void) does not stop the warnings; a more elaborate fudge is
449        needed. I've used a macro to implement this.
451    7.  Minor change to pcretest.c to avoid a compiler warning.
453    8.  Added four artifical Unicode properties to help with an option to make
454        \s etc use properties (see next item). The new properties are: Xan
455        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
457    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
458        use Unicode properties. (*UCP) at the start of a pattern can be used to set
459        this option. Modified pcretest to add /W to test this facility. Added
460        REG_UCP to make it available via the POSIX interface.
462    10. Added --line-buffered to pcregrep.
464    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
465        studied, and the match started with a letter with a code point greater than
466        127 whose first byte was different to the first byte of the other case of
467        the letter, the other case of this starting letter was not recognized
468        (#976).
470    12. If a pattern that was studied started with a repeated Unicode property
471        test, for example, \p{Nd}+, there was the theoretical possibility of
472        setting up an incorrect bitmap of starting bytes, but fortunately it could
473        not have actually happened in practice until change 8 above was made (it
474        added property types that matched character-matching opcodes).
476    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
477        possible starting bytes for non-anchored patterns.
479    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
480        \R, and also a number of cases that involve Unicode properties, both
481        explicit and implicit when PCRE_UCP is set.
483    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
484        input, it could crash or give wrong results if characters with values
485        greater than 0xc0 were present in the subject string. (Detail: it assumed
486        UTF-8 input when processing these items.)
488    16. Added a lot of (int) casts to avoid compiler warnings in systems where
489        size_t is 64-bit (#991).
491    17. Added a check for running out of memory when PCRE is compiled with
492        --disable-stack-for-recursion (#990).
494    18. If the last data line in a file for pcretest does not have a newline on
495        the end, a newline was missing in the output.
497    19. The default pcre_chartables.c file recognizes only ASCII characters (values
498        less than 128) in its various bitmaps. However, there is a facility for
499        generating tables according to the current locale when PCRE is compiled. It
500        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
501        characters, are recognized by isspace() and therefore were getting set in
502        these tables, and indeed these tables seem to approximate to ISO 8859. This
503        caused a problem in UTF-8 mode when pcre_study() was used to create a list
504        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
505        which of course cannot start UTF-8 characters. I have changed the code so
506        that only real ASCII characters (less than 128) and the correct starting
507        bytes for UTF-8 encodings are set for characters greater than 127 when in
508        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
509        altogether.)
511    20. Added the /T option to pcretest so as to be able to run tests with non-
512        standard character tables, thus making it possible to include the tests
513        used for 19 above in the standard set of tests.
515    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
516        reference to a subpattern the other side of a comment that contains an
517        opening parenthesis caused either an internal compiling error, or a
518        reference to the wrong subpattern.
521    Version 8.02 19-Mar-2010
522    ------------------------
524    1.  The Unicode data tables have been updated to Unicode 5.2.0.
526    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
527        configured.
529    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
530        original author of that file, following a query about its status.
532    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
533        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
535    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
536        quantifier applied to a forward-referencing subroutine call, could compile
537        incorrect code or give the error "internal error: previously-checked
538        referenced subpattern not found".
540    6.  Both MS Visual Studio and Symbian OS have problems with initializing
541        variables to point to external functions. For these systems, therefore,
542        pcre_malloc etc. are now initialized to local functions that call the
543        relevant global functions.
545    7.  There were two entries missing in the vectors called coptable and poptable
546        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
547        I've fixed the data, and added a kludgy way of testing at compile time that
548        the lengths are correct (equal to the number of opcodes).
550    8.  Following on from 7, I added a similar kludge to check the length of the
551        eint vector in pcreposix.c.
553    9.  Error texts for pcre_compile() are held as one long string to avoid too
554        much relocation at load time. To find a text, the string is searched,
555        counting zeros. There was no check for running off the end of the string,
556        which could happen if a new error number was added without updating the
557        string.
559    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
561    11. \K was not working if it appeared in an atomic group or in a group that
562        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
563        \K is "not well defined" if used in an assertion. PCRE now accepts it if
564        the assertion is positive, but not if it is negative.
566    12. Change 11 fortuitously reduced the size of the stack frame used in the
567        "match()" function of pcre_exec.c by one pointer. Forthcoming
568        implementation of support for (*MARK) will need an extra pointer on the
569        stack; I have reserved it now, so that the stack frame size does not
570        decrease.
572    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
573        item in branch that calls a recursion is a subroutine call - as in the
574        second branch in the above example - was incorrectly given the compile-
575        time error "recursive call could loop indefinitely" because pcre_compile()
576        was not correctly checking the subroutine for matching a non-empty string.
578    14. The checks for overrunning compiling workspace could trigger after an
579        overrun had occurred. This is a "should never occur" error, but it can be
580        triggered by pathological patterns such as hundreds of nested parentheses.
581        The checks now trigger 100 bytes before the end of the workspace.
583    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
586    Version 8.01 19-Jan-2010
587    ------------------------
589    1.  If a pattern contained a conditional subpattern with only one branch (in
590        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
591        computed the wrong minimum data length (which is of course zero for such
592        subpatterns). This could cause incorrect "no match" results.
594    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
595        the pattern is reset in the first branch, pcre_compile() failed with
596        "internal error: code overflow at offset...". This happened only when
597        the reset was to the original external option setting. (An optimization
598        abstracts leading options settings into an external setting, which was the
599        cause of this.)
601    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
602        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
603        assertion pattern did not match (meaning that the assertion was true), it
604        was incorrectly treated as false if the SKIP had been reached during the
605        matching. This also applied to assertions used as conditions.
607    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
608        assertion subpattern, including such a pattern used as a condition,
609        unpredictable results occurred, instead of the error return
612    5.  The C++ GlobalReplace function was not working like Perl for the special
613        situation when an empty string is matched. It now does the fancy magic
614        stuff that is necessary.
616    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
617        removed. (These were left over from very, very early versions of PCRE.)
619    7.  Some cosmetic changes to the code to make life easier when compiling it
620        as part of something else:
622        (a) Change DEBUG to PCRE_DEBUG.
624        (b) In pcre_compile(), rename the member of the "branch_chain" structure
625            called "current" as "current_branch", to prevent a collision with the
626            Linux macro when compiled as a kernel module.
628        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
629            prevent a collision with the Linux macro when compiled as a kernel
630            module.
632    8.  In pcre_compile() there are some checks for integer overflows that used to
633        cast potentially large values to (double). This has been changed to that
634        when building, a check for int64_t is made, and if it is found, it is used
635        instead, thus avoiding the use of floating point arithmetic. (There is no
636        other use of FP in PCRE.) If int64_t is not found, the fallback is to
637        double.
639    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
640        2005 (difference between two addresses compared to an unsigned value).
642    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
643        custom one, because of the following reported problem in Windows:
645          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
646              under Win32.
647          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
648              therefore missing the function definition.
649          - The compiler thus generates a "C" signature for the test function.
650          - The linker fails to find the "C" function.
651          - PCRE fails to configure if asked to do so against libbz2.
653    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
654        messages were output:
656          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
657          rerunning libtoolize, to keep the correct libtool macros in-tree.
658          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
660        I have done both of these things.
662    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
663        most of the time, it *can* run out if it is given a pattern that contains a
664        runaway infinite recursion. I updated the discussion in the pcrestack man
665        page.
667    13. Now that we have gone to the x.xx style of version numbers, the minor
668        version may start with zero. Using 08 or 09 is a bad idea because users
669        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
670        interpreted as invalid octal numbers. I've updated the previous comment in
671        configure.ac, and also added a check that gives an error if 08 or 09 are
672        used.
674    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
675        causing partial matching to fail when the end of the subject matched \W
676        in a UTF-8 pattern where \W was quantified with a minimum of 3.
678    15. There were some discrepancies between the declarations in pcre_internal.h
679        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
680        their definitions. The declarations used "const uschar *" and the
681        definitions used USPTR. Even though USPTR is normally defined as "const
682        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
683        reported that: "This difference in casting confuses some C++ compilers, for
684        example, SunCC recognizes above declarations as different functions and
685        generates broken code for hbpcre." I have changed the declarations to use
686        USPTR.
688    16. GNU libtool is named differently on some systems. The autogen.sh script now
689        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
690        (FreeBSD).
692    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
693        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
694        comment: "Figure out how to create a longlong from a string: strtoll and
695        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
696        instance, but it only takes 2 args instead of 3!"
698    18. A subtle bug concerned with back references has been fixed by a change of
699        specification, with a corresponding code fix. A pattern such as
700        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
701        refers, was giving matches when it shouldn't. For example, xa=xaaa would
702        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
703        same bug. Such groups have to be quantified to be useful, or contained
704        inside another quantified group. (If there's no repetition, the reference
705        can never match.) The problem arises because, having left the group and
706        moved on to the rest of the pattern, a later failure that backtracks into
707        the group uses the captured value from the final iteration of the group
708        rather than the correct earlier one. I have fixed this in PCRE by forcing
709        any group that contains a reference to itself to be an atomic group; that
710        is, there cannot be any backtracking into it once it has completed. This is
711        similar to recursive and subroutine calls.
714    Version 8.00 19-Oct-09
715    ----------------------
717    1.  The table for translating pcre_compile() error codes into POSIX error codes
718        was out-of-date, and there was no check on the pcre_compile() error code
719        being within the table. This could lead to an OK return being given in
720        error.
722    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
723        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
724        in a Windows environment.
726    3.  The pcregrep --count option prints the count for each file even when it is
727        zero, as does GNU grep. However, pcregrep was also printing all files when
728        --files-with-matches was added. Now, when both options are given, it prints
729        counts only for those files that have at least one match. (GNU grep just
730        prints the file name in this circumstance, but including the count seems
731        more useful - otherwise, why use --count?) Also ensured that the
732        combination -clh just lists non-zero counts, with no names.
734    4.  The long form of the pcregrep -F option was incorrectly implemented as
735        --fixed_strings instead of --fixed-strings. This is an incompatible change,
736        but it seems right to fix it, and I didn't think it was worth preserving
737        the old behaviour.
739    5.  The command line items --regex=pattern and --regexp=pattern were not
740        recognized by pcregrep, which required --regex pattern or --regexp pattern
741        (with a space rather than an '='). The man page documented the '=' forms,
742        which are compatible with GNU grep; these now work.
744    6.  No libpcreposix.pc file was created for pkg-config; there was just
745        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
747    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
748        when UCP support is not needed, by modifying the Python script that
749        generates it from Unicode data files. This should not matter if the module
750        is correctly used as a library, but I received one complaint about 50K of
751        unwanted data. My guess is that the person linked everything into his
752        program rather than using a library. Anyway, it does no harm.
754    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
755        was a minimum greater than 1 for a wide character in a possessive
756        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
757        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
758        character. Chaos in the form of incorrect output or a compiling loop could
759        result.
761    9.  The restrictions on what a pattern can contain when partial matching is
762        requested for pcre_exec() have been removed. All patterns can now be
763        partially matched by this function. In addition, if there are at least two
764        slots in the offset vector, the offset of the earliest inspected character
765        for the match and the offset of the end of the subject are set in them when
766        PCRE_ERROR_PARTIAL is returned.
768    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
769        synonymous with PCRE_PARTIAL, for backwards compatibility, and
770        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
771        and may be more useful for multi-segment matching.
773    11. Partial matching with pcre_exec() is now more intuitive. A partial match
774        used to be given if ever the end of the subject was reached; now it is
775        given only if matching could not proceed because another character was
776        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
777        string "Z", which now yields "no match" instead of "partial match". In the
778        case of pcre_dfa_exec(), "no match" is given if every matching path for the
779        final character ended with (*FAIL).
781    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
782        if the pattern had a "must contain" character that was already found in the
783        earlier partial match, unless partial matching was again requested. For
784        example, with the pattern /dog.(body)?/, the "must contain" character is
785        "g". If the first part-match was for the string "dog", restarting with
786        "sbody" failed. This bug has been fixed.
788    13. The string returned by pcre_dfa_exec() after a partial match has been
789        changed so that it starts at the first inspected character rather than the
790        first character of the match. This makes a difference only if the pattern
791        starts with a lookbehind assertion or \b or \B (\K is not supported by
792        pcre_dfa_exec()). It's an incompatible change, but it makes the two
793        matching functions compatible, and I think it's the right thing to do.
795    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
796        so that the demonstration program is easily available in environments where
797        PCRE has not been installed from source.
799    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
800        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
801        library.
803    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
804        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
805        is not the first non-POSIX option to be added. Clearly some people find
806        these options useful.
808    17. If a caller to the POSIX matching function regexec() passes a non-zero
809        value for nmatch with a NULL value for pmatch, the value of
810        nmatch is forced to zero.
812    18. RunGrepTest did not have a test for the availability of the -u option of
813        the diff command, as RunTest does. It now checks in the same way as
814        RunTest, and also checks for the -b option.
816    19. If an odd number of negated classes containing just a single character
817        interposed, within parentheses, between a forward reference to a named
818        subpattern and the definition of the subpattern, compilation crashed with
819        an internal error, complaining that it could not find the referenced
820        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
821        [The bug was that it was starting one character too far in when skipping
822        over the character class, thus treating the ] as data rather than
823        terminating the class. This meant it could skip too much.]
825    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
826        /g option in pcretest when the pattern contains \K, which makes it possible
827        to have an empty string match not at the start, even when the pattern is
828        anchored. Updated pcretest and pcredemo to use this option.
830    21. If the maximum number of capturing subpatterns in a recursion was greater
831        than the maximum at the outer level, the higher number was returned, but
832        with unset values at the outer level. The correct (outer level) value is
833        now given.
835    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
836        PCRE did not set those parentheses (unlike Perl). I have now found a way to
837        make it do so. The string so far is captured, making this feature
838        compatible with Perl.
840    23. The tests have been re-organized, adding tests 11 and 12, to make it
841        possible to check the Perl 5.10 features against Perl 5.10.
843    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
844        pattern matches a fixed length string. PCRE did not allow this; now it
845        does. Neither allows recursion.
847    25. I finally figured out how to implement a request to provide the minimum
848        length of subject string that was needed in order to match a given pattern.
849        (It was back references and recursion that I had previously got hung up
850        on.) This code has now been added to pcre_study(); it finds a lower bound
851        to the length of subject needed. It is not necessarily the greatest lower
852        bound, but using it to avoid searching strings that are too short does give
853        some useful speed-ups. The value is available to calling programs via
854        pcre_fullinfo().
856    26. While implementing 25, I discovered to my embarrassment that pcretest had
857        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
858        study optimizations had never been tested with that matching function.
859        Oops. What is worse, even when it was passed study data, there was a bug in
860        pcre_dfa_exec() that meant it never actually used it. Double oops. There
861        were also very few tests of studied patterns with pcre_dfa_exec().
863    27. If (?| is used to create subpatterns with duplicate numbers, they are now
864        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
865        on the other side of the coin, they are no longer allowed to have different
866        names, because these cannot be distinguished in PCRE, and this has caused
867        confusion. (This is a difference from Perl.)
869    28. When duplicate subpattern names are present (necessarily with different
870        numbers, as required by 27 above), and a test is made by name in a
871        conditional pattern, either for a subpattern having been matched, or for
872        recursion in such a pattern, all the associated numbered subpatterns are
873        tested, and the overall condition is true if the condition is true for any
874        one of them. This is the way Perl works, and is also more like the way
875        testing by number works.
878    Version 7.9 11-Apr-09
879  ---------------------  ---------------------
881  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 891  Version 7.9 xx-xxx-09
891      but BOOL is not.      but BOOL is not.
893  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
894      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
896  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
897      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 94  Version 7.9 xx-xxx-09 Line 968  Version 7.9 xx-xxx-09
968  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
969      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
970      included within another project.      included within another project.
972  24. Steven Van Ingelgem's patches to add more options to the CMake support,  24. Steven Van Ingelgem's patches to add more options to the CMake support,
973      slightly modified by me:      slightly modified by me:
975        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
976            not building pcregrep.            not building pcregrep.
978        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
979            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
981  25. Forward references, both numeric and by name, in patterns that made use of  25. Forward references, both numeric and by name, in patterns that made use of
982      duplicate group numbers, could behave incorrectly or give incorrect errors,      duplicate group numbers, could behave incorrectly or give incorrect errors,
983      because when scanning forward to find the reference group, PCRE was not      because when scanning forward to find the reference group, PCRE was not
984      taking into account the duplicate group numbers. A pattern such as      taking into account the duplicate group numbers. A pattern such as
985      ^X(?3)(a)(?|(b)|(q))(Y) is an example.      ^X(?3)(a)(?|(b)|(q))(Y) is an example.
987    26. Changed a few more instances of "const unsigned char *" to USPTR, making
988        the feature of a custom pointer more persuasive (as requested by a user).
990    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
991        pcretest.c, inside #ifndefs, because it seems they are sometimes already
992        pre-defined.
994    28. Added support for (*UTF8) at the start of a pattern.
996    29. Arrange for flags added by the "release type" setting in CMake to be shown
997        in the configuration summary.
1000  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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