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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    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).
213    Version 8.12 15-Jan-2011
214    ------------------------
216    1.  Fixed some typos in the markup of the man pages, and wrote a script that
217        checks for such things as part of the documentation building process.
219    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
220        --match-limit and --recursion-limit options (added for 8.11). In
221        particular, this made one of the standard tests fail. (The integer value
222        went into the wrong half of a long int.)
224    3.  If the --colour option was given to pcregrep with -v (invert match), it
225        did strange things, either producing crazy output, or crashing. It should,
226        of course, ignore a request for colour when reporting lines that do not
227        match.
229    4.  Another pcregrep bug caused similar problems if --colour was specified with
230        -M (multiline) and the pattern match finished with a line ending.
232    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
233        matched in multiline mode, the following line was shown as part of the
234        match. This seems wrong, so I have changed it.
236    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
237        the check for further matches in the same line (so they could be coloured)
238        to overrun the end of the current line. If another match was found, it was
239        incorrectly shown (and then shown again when found in the next line).
241    7.  If pcregrep was compiled under Windows, there was a reference to the
242        function pcregrep_exit() before it was defined. I am assuming this was
243        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
244        reported by a user. I've moved the definition above the reference.
247    Version 8.11 10-Dec-2010
248    ------------------------
250    1.  (*THEN) was not working properly if there were untried alternatives prior
251        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
252        backtracked to try for "b" instead of moving to the next alternative branch
253        at the same level (in this case, to look for "c"). The Perl documentation
254        is clear that when (*THEN) is backtracked onto, it goes to the "next
255        alternative in the innermost enclosing group".
257    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
258        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
259        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
260        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
261        (*THEN).
263    3.  If \s appeared in a character class, it removed the VT character from
264        the class, even if it had been included by some previous item, for example
265        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
266        of \s, but is part of the POSIX "space" class.)
268    4.  A partial match never returns an empty string (because you can always
269        match an empty string at the end of the subject); however the checking for
270        an empty string was starting at the "start of match" point. This has been
271        changed to the "earliest inspected character" point, because the returned
272        data for a partial match starts at this character. This means that, for
273        example, /(?<=abc)def/ gives a partial match for the subject "abc"
274        (previously it gave "no match").
276    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
277        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
278        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
279        has an implication that the given string is incomplete (because a partial
280        match is preferred over a full match). For this reason, these items now
281        give a partial match in this situation. [Aside: previously, the one case
282        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
283        match rather than a full match, which was wrong by the old rules, but is
284        now correct.]
286    6.  There was a bug in the handling of #-introduced comments, recognized when
287        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
288        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
289        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
290        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
291        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
292        places in pcre_compile().
294    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
295        comments when looking ahead for named forward references to subpatterns,
296        the only newline sequence it recognized was NL. It now handles newlines
297        according to the set newline convention.
299    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
300        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
301        cater for a lack of strerror(). These oversights have been fixed.
303    9.  Added --match-limit and --recursion-limit to pcregrep.
305    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
307    11. When the -o option was used, pcregrep was setting a return code of 1, even
308        when matches were found, and --line-buffered was not being honoured.
310    12. Added an optional parentheses number to the -o and --only-matching options
311        of pcregrep.
313    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
314        can match an empty string. The code to do it in pcretest and pcredemo
315        needed fixing:
317        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
318            only one byte after an empty string match just before CRLF (this case
319            just got forgotten; "any" and "anycrlf" were OK).
321        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
322            mode when an empty string match preceded an ASCII character followed by
323            a non-ASCII character. (The code for advancing by one character rather
324            than one byte was nonsense.)
326        (c) The pcredemo.c sample program did not have any code at all to handle
327            the cases when CRLF is a valid newline sequence.
329    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
330        as a starting offset was within the subject string. There is now a new
331        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
332        negative or greater than the length of the string. In order to test this,
333        pcretest is extended to allow the setting of negative starting offsets.
335    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
336        starting offset points to the beginning of a UTF-8 character was
337        unnecessarily clumsy. I tidied it up.
339    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
340        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
342    17. Nobody had reported that the --include_dir option, which was added in
343        release 7.7 should have been called --include-dir (hyphen, not underscore)
344        for compatibility with GNU grep. I have changed it to --include-dir, but
345        left --include_dir as an undocumented synonym, and the same for
346        --exclude-dir, though that is not available in GNU grep, at least as of
347        release 2.5.4.
349    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
350        characters from a string of bytes) have been redefined so as not to use
351        loops, in order to improve performance in some environments. At the same
352        time, I abstracted some of the common code into auxiliary macros to save
353        repetition (this should not affect the compiled code).
355    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
356        compile-time error is now given if \c is not followed by an ASCII
357        character, that is, a byte less than 128. (In EBCDIC mode, the code is
358        different, and any byte value is allowed.)
360    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
361        START_OPTIMIZE option, which is now allowed at compile time - but just
362        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
363        to pcregrep and other applications that have no direct access to PCRE
364        options. The new /Y option in pcretest sets this option when calling
365        pcre_compile().
367    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
368        back references. Groups containing recursive back references were forced to
369        be atomic by that change, but in the case of named groups, the amount of
370        memory required was incorrectly computed, leading to "Failed: internal
371        error: code overflow". This has been fixed.
373    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
374        pcretest.c, to avoid build problems in some Borland environments.
377    Version 8.10 25-Jun-2010
378    ------------------------
380    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
381        THEN.
383    2.  (*ACCEPT) was not working when inside an atomic group.
385    3.  Inside a character class, \B is treated as a literal by default, but
386        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
387        causes the error). The code is unchanged, but I tidied the documentation.
389    4.  Inside a character class, PCRE always treated \R and \X as literals,
390        whereas Perl faults them if its -w option is set. I have changed PCRE so
391        that it faults them when PCRE_EXTRA is set.
393    5.  Added support for \N, which always matches any character other than
394        newline. (It is the same as "." when PCRE_DOTALL is not set.)
396    6.  When compiling pcregrep with newer versions of gcc which may have
397        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
398        declared with attribute warn_unused_result" were given. Just casting the
399        result to (void) does not stop the warnings; a more elaborate fudge is
400        needed. I've used a macro to implement this.
402    7.  Minor change to pcretest.c to avoid a compiler warning.
404    8.  Added four artifical Unicode properties to help with an option to make
405        \s etc use properties (see next item). The new properties are: Xan
406        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
408    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
409        use Unicode properties. (*UCP) at the start of a pattern can be used to set
410        this option. Modified pcretest to add /W to test this facility. Added
411        REG_UCP to make it available via the POSIX interface.
413    10. Added --line-buffered to pcregrep.
415    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
416        studied, and the match started with a letter with a code point greater than
417        127 whose first byte was different to the first byte of the other case of
418        the letter, the other case of this starting letter was not recognized
419        (#976).
421    12. If a pattern that was studied started with a repeated Unicode property
422        test, for example, \p{Nd}+, there was the theoretical possibility of
423        setting up an incorrect bitmap of starting bytes, but fortunately it could
424        not have actually happened in practice until change 8 above was made (it
425        added property types that matched character-matching opcodes).
427    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
428        possible starting bytes for non-anchored patterns.
430    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
431        \R, and also a number of cases that involve Unicode properties, both
432        explicit and implicit when PCRE_UCP is set.
434    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
435        input, it could crash or give wrong results if characters with values
436        greater than 0xc0 were present in the subject string. (Detail: it assumed
437        UTF-8 input when processing these items.)
439    16. Added a lot of (int) casts to avoid compiler warnings in systems where
440        size_t is 64-bit (#991).
442    17. Added a check for running out of memory when PCRE is compiled with
443        --disable-stack-for-recursion (#990).
445    18. If the last data line in a file for pcretest does not have a newline on
446        the end, a newline was missing in the output.
448    19. The default pcre_chartables.c file recognizes only ASCII characters (values
449        less than 128) in its various bitmaps. However, there is a facility for
450        generating tables according to the current locale when PCRE is compiled. It
451        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
452        characters, are recognized by isspace() and therefore were getting set in
453        these tables, and indeed these tables seem to approximate to ISO 8859. This
454        caused a problem in UTF-8 mode when pcre_study() was used to create a list
455        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
456        which of course cannot start UTF-8 characters. I have changed the code so
457        that only real ASCII characters (less than 128) and the correct starting
458        bytes for UTF-8 encodings are set for characters greater than 127 when in
459        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
460        altogether.)
462    20. Added the /T option to pcretest so as to be able to run tests with non-
463        standard character tables, thus making it possible to include the tests
464        used for 19 above in the standard set of tests.
466    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
467        reference to a subpattern the other side of a comment that contains an
468        opening parenthesis caused either an internal compiling error, or a
469        reference to the wrong subpattern.
472    Version 8.02 19-Mar-2010
473    ------------------------
475    1.  The Unicode data tables have been updated to Unicode 5.2.0.
477    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
478        configured.
480    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
481        original author of that file, following a query about its status.
483    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
484        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
486    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
487        quantifier applied to a forward-referencing subroutine call, could compile
488        incorrect code or give the error "internal error: previously-checked
489        referenced subpattern not found".
491    6.  Both MS Visual Studio and Symbian OS have problems with initializing
492        variables to point to external functions. For these systems, therefore,
493        pcre_malloc etc. are now initialized to local functions that call the
494        relevant global functions.
496    7.  There were two entries missing in the vectors called coptable and poptable
497        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
498        I've fixed the data, and added a kludgy way of testing at compile time that
499        the lengths are correct (equal to the number of opcodes).
501    8.  Following on from 7, I added a similar kludge to check the length of the
502        eint vector in pcreposix.c.
504    9.  Error texts for pcre_compile() are held as one long string to avoid too
505        much relocation at load time. To find a text, the string is searched,
506        counting zeros. There was no check for running off the end of the string,
507        which could happen if a new error number was added without updating the
508        string.
510    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
512    11. \K was not working if it appeared in an atomic group or in a group that
513        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
514        \K is "not well defined" if used in an assertion. PCRE now accepts it if
515        the assertion is positive, but not if it is negative.
517    12. Change 11 fortuitously reduced the size of the stack frame used in the
518        "match()" function of pcre_exec.c by one pointer. Forthcoming
519        implementation of support for (*MARK) will need an extra pointer on the
520        stack; I have reserved it now, so that the stack frame size does not
521        decrease.
523    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
524        item in branch that calls a recursion is a subroutine call - as in the
525        second branch in the above example - was incorrectly given the compile-
526        time error "recursive call could loop indefinitely" because pcre_compile()
527        was not correctly checking the subroutine for matching a non-empty string.
529    14. The checks for overrunning compiling workspace could trigger after an
530        overrun had occurred. This is a "should never occur" error, but it can be
531        triggered by pathological patterns such as hundreds of nested parentheses.
532        The checks now trigger 100 bytes before the end of the workspace.
534    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
537    Version 8.01 19-Jan-2010
538    ------------------------
540    1.  If a pattern contained a conditional subpattern with only one branch (in
541        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
542        computed the wrong minimum data length (which is of course zero for such
543        subpatterns). This could cause incorrect "no match" results.
545    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
546        the pattern is reset in the first branch, pcre_compile() failed with
547        "internal error: code overflow at offset...". This happened only when
548        the reset was to the original external option setting. (An optimization
549        abstracts leading options settings into an external setting, which was the
550        cause of this.)
552    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
553        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
554        assertion pattern did not match (meaning that the assertion was true), it
555        was incorrectly treated as false if the SKIP had been reached during the
556        matching. This also applied to assertions used as conditions.
558    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
559        assertion subpattern, including such a pattern used as a condition,
560        unpredictable results occurred, instead of the error return
563    5.  The C++ GlobalReplace function was not working like Perl for the special
564        situation when an empty string is matched. It now does the fancy magic
565        stuff that is necessary.
567    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
568        removed. (These were left over from very, very early versions of PCRE.)
570    7.  Some cosmetic changes to the code to make life easier when compiling it
571        as part of something else:
573        (a) Change DEBUG to PCRE_DEBUG.
575        (b) In pcre_compile(), rename the member of the "branch_chain" structure
576            called "current" as "current_branch", to prevent a collision with the
577            Linux macro when compiled as a kernel module.
579        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
580            prevent a collision with the Linux macro when compiled as a kernel
581            module.
583    8.  In pcre_compile() there are some checks for integer overflows that used to
584        cast potentially large values to (double). This has been changed to that
585        when building, a check for int64_t is made, and if it is found, it is used
586        instead, thus avoiding the use of floating point arithmetic. (There is no
587        other use of FP in PCRE.) If int64_t is not found, the fallback is to
588        double.
590    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
591        2005 (difference between two addresses compared to an unsigned value).
593    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
594        custom one, because of the following reported problem in Windows:
596          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
597              under Win32.
598          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
599              therefore missing the function definition.
600          - The compiler thus generates a "C" signature for the test function.
601          - The linker fails to find the "C" function.
602          - PCRE fails to configure if asked to do so against libbz2.
604    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
605        messages were output:
607          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
608          rerunning libtoolize, to keep the correct libtool macros in-tree.
609          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
611        I have done both of these things.
613    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
614        most of the time, it *can* run out if it is given a pattern that contains a
615        runaway infinite recursion. I updated the discussion in the pcrestack man
616        page.
618    13. Now that we have gone to the x.xx style of version numbers, the minor
619        version may start with zero. Using 08 or 09 is a bad idea because users
620        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
621        interpreted as invalid octal numbers. I've updated the previous comment in
622        configure.ac, and also added a check that gives an error if 08 or 09 are
623        used.
625    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
626        causing partial matching to fail when the end of the subject matched \W
627        in a UTF-8 pattern where \W was quantified with a minimum of 3.
629    15. There were some discrepancies between the declarations in pcre_internal.h
630        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
631        their definitions. The declarations used "const uschar *" and the
632        definitions used USPTR. Even though USPTR is normally defined as "const
633        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
634        reported that: "This difference in casting confuses some C++ compilers, for
635        example, SunCC recognizes above declarations as different functions and
636        generates broken code for hbpcre." I have changed the declarations to use
637        USPTR.
639    16. GNU libtool is named differently on some systems. The autogen.sh script now
640        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
641        (FreeBSD).
643    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
644        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
645        comment: "Figure out how to create a longlong from a string: strtoll and
646        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
647        instance, but it only takes 2 args instead of 3!"
649    18. A subtle bug concerned with back references has been fixed by a change of
650        specification, with a corresponding code fix. A pattern such as
651        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
652        refers, was giving matches when it shouldn't. For example, xa=xaaa would
653        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
654        same bug. Such groups have to be quantified to be useful, or contained
655        inside another quantified group. (If there's no repetition, the reference
656        can never match.) The problem arises because, having left the group and
657        moved on to the rest of the pattern, a later failure that backtracks into
658        the group uses the captured value from the final iteration of the group
659        rather than the correct earlier one. I have fixed this in PCRE by forcing
660        any group that contains a reference to itself to be an atomic group; that
661        is, there cannot be any backtracking into it once it has completed. This is
662        similar to recursive and subroutine calls.
665    Version 8.00 19-Oct-09
666    ----------------------
668    1.  The table for translating pcre_compile() error codes into POSIX error codes
669        was out-of-date, and there was no check on the pcre_compile() error code
670        being within the table. This could lead to an OK return being given in
671        error.
673    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
674        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
675        in a Windows environment.
677    3.  The pcregrep --count option prints the count for each file even when it is
678        zero, as does GNU grep. However, pcregrep was also printing all files when
679        --files-with-matches was added. Now, when both options are given, it prints
680        counts only for those files that have at least one match. (GNU grep just
681        prints the file name in this circumstance, but including the count seems
682        more useful - otherwise, why use --count?) Also ensured that the
683        combination -clh just lists non-zero counts, with no names.
685    4.  The long form of the pcregrep -F option was incorrectly implemented as
686        --fixed_strings instead of --fixed-strings. This is an incompatible change,
687        but it seems right to fix it, and I didn't think it was worth preserving
688        the old behaviour.
690    5.  The command line items --regex=pattern and --regexp=pattern were not
691        recognized by pcregrep, which required --regex pattern or --regexp pattern
692        (with a space rather than an '='). The man page documented the '=' forms,
693        which are compatible with GNU grep; these now work.
695    6.  No libpcreposix.pc file was created for pkg-config; there was just
696        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
698    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
699        when UCP support is not needed, by modifying the Python script that
700        generates it from Unicode data files. This should not matter if the module
701        is correctly used as a library, but I received one complaint about 50K of
702        unwanted data. My guess is that the person linked everything into his
703        program rather than using a library. Anyway, it does no harm.
705    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
706        was a minimum greater than 1 for a wide character in a possessive
707        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
708        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
709        character. Chaos in the form of incorrect output or a compiling loop could
710        result.
712    9.  The restrictions on what a pattern can contain when partial matching is
713        requested for pcre_exec() have been removed. All patterns can now be
714        partially matched by this function. In addition, if there are at least two
715        slots in the offset vector, the offset of the earliest inspected character
716        for the match and the offset of the end of the subject are set in them when
717        PCRE_ERROR_PARTIAL is returned.
719    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
720        synonymous with PCRE_PARTIAL, for backwards compatibility, and
721        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
722        and may be more useful for multi-segment matching.
724    11. Partial matching with pcre_exec() is now more intuitive. A partial match
725        used to be given if ever the end of the subject was reached; now it is
726        given only if matching could not proceed because another character was
727        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
728        string "Z", which now yields "no match" instead of "partial match". In the
729        case of pcre_dfa_exec(), "no match" is given if every matching path for the
730        final character ended with (*FAIL).
732    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
733        if the pattern had a "must contain" character that was already found in the
734        earlier partial match, unless partial matching was again requested. For
735        example, with the pattern /dog.(body)?/, the "must contain" character is
736        "g". If the first part-match was for the string "dog", restarting with
737        "sbody" failed. This bug has been fixed.
739    13. The string returned by pcre_dfa_exec() after a partial match has been
740        changed so that it starts at the first inspected character rather than the
741        first character of the match. This makes a difference only if the pattern
742        starts with a lookbehind assertion or \b or \B (\K is not supported by
743        pcre_dfa_exec()). It's an incompatible change, but it makes the two
744        matching functions compatible, and I think it's the right thing to do.
746    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
747        so that the demonstration program is easily available in environments where
748        PCRE has not been installed from source.
750    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
751        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
752        library.
754    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
755        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
756        is not the first non-POSIX option to be added. Clearly some people find
757        these options useful.
759    17. If a caller to the POSIX matching function regexec() passes a non-zero
760        value for nmatch with a NULL value for pmatch, the value of
761        nmatch is forced to zero.
763    18. RunGrepTest did not have a test for the availability of the -u option of
764        the diff command, as RunTest does. It now checks in the same way as
765        RunTest, and also checks for the -b option.
767    19. If an odd number of negated classes containing just a single character
768        interposed, within parentheses, between a forward reference to a named
769        subpattern and the definition of the subpattern, compilation crashed with
770        an internal error, complaining that it could not find the referenced
771        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
772        [The bug was that it was starting one character too far in when skipping
773        over the character class, thus treating the ] as data rather than
774        terminating the class. This meant it could skip too much.]
776    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
777        /g option in pcretest when the pattern contains \K, which makes it possible
778        to have an empty string match not at the start, even when the pattern is
779        anchored. Updated pcretest and pcredemo to use this option.
781    21. If the maximum number of capturing subpatterns in a recursion was greater
782        than the maximum at the outer level, the higher number was returned, but
783        with unset values at the outer level. The correct (outer level) value is
784        now given.
786    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
787        PCRE did not set those parentheses (unlike Perl). I have now found a way to
788        make it do so. The string so far is captured, making this feature
789        compatible with Perl.
791    23. The tests have been re-organized, adding tests 11 and 12, to make it
792        possible to check the Perl 5.10 features against Perl 5.10.
794    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
795        pattern matches a fixed length string. PCRE did not allow this; now it
796        does. Neither allows recursion.
798    25. I finally figured out how to implement a request to provide the minimum
799        length of subject string that was needed in order to match a given pattern.
800        (It was back references and recursion that I had previously got hung up
801        on.) This code has now been added to pcre_study(); it finds a lower bound
802        to the length of subject needed. It is not necessarily the greatest lower
803        bound, but using it to avoid searching strings that are too short does give
804        some useful speed-ups. The value is available to calling programs via
805        pcre_fullinfo().
807    26. While implementing 25, I discovered to my embarrassment that pcretest had
808        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
809        study optimizations had never been tested with that matching function.
810        Oops. What is worse, even when it was passed study data, there was a bug in
811        pcre_dfa_exec() that meant it never actually used it. Double oops. There
812        were also very few tests of studied patterns with pcre_dfa_exec().
814    27. If (?| is used to create subpatterns with duplicate numbers, they are now
815        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
816        on the other side of the coin, they are no longer allowed to have different
817        names, because these cannot be distinguished in PCRE, and this has caused
818        confusion. (This is a difference from Perl.)
820    28. When duplicate subpattern names are present (necessarily with different
821        numbers, as required by 27 above), and a test is made by name in a
822        conditional pattern, either for a subpattern having been matched, or for
823        recursion in such a pattern, all the associated numbered subpatterns are
824        tested, and the overall condition is true if the condition is true for any
825        one of them. This is the way Perl works, and is also more like the way
826        testing by number works.
829    Version 7.9 11-Apr-09
830    ---------------------
832    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
833        (pcretest), all targets were linked against these libraries. This included
834        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
835        libraries. This caused unwanted dependencies to be created. This problem
836        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
837        pcretest is linked with readline.
839    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
840        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
841        moved outside it again, because FALSE and TRUE are already defined in AIX,
842        but BOOL is not.
844    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
845        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
847    4.  The pcregrep documentation said spaces were inserted as well as colons (or
848        hyphens) following file names and line numbers when outputting matching
849        lines. This is not true; no spaces are inserted. I have also clarified the
850        wording for the --colour (or --color) option.
852    5.  In pcregrep, when --colour was used with -o, the list of matching strings
853        was not coloured; this is different to GNU grep, so I have changed it to be
854        the same.
856    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
857        each matching line was coloured. Now it goes on to look for further matches
858        of any of the test patterns, which is the same behaviour as GNU grep.
860    7.  A pattern that could match an empty string could cause pcregrep to loop; it
861        doesn't make sense to accept an empty string match in pcregrep, so I have
862        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
863        seems to be how GNU grep behaves.
865    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
866        start or after a newline", because the conditional assertion was not being
867        correctly handled. The rule now is that both the assertion and what follows
868        in the first alternative must satisfy the test.
870    9.  If auto-callout was enabled in a pattern with a conditional group whose
871        condition was an assertion, PCRE could crash during matching, both with
872        pcre_exec() and pcre_dfa_exec().
874    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
875        used for matching.
877    11. Unicode property support in character classes was not working for
878        characters (bytes) greater than 127 when not in UTF-8 mode.
880    12. Added the -M command line option to pcretest.
882    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
884    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
886    16. Added comments and documentation about mis-use of no_arg in the C++
887        wrapper.
889    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
890        from Martin Jerabek that uses macro names for all relevant character and
891        string constants.
893    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
894        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
895        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
896        these, but not everybody uses configure.
898    19. A conditional group that had only one branch was not being correctly
899        recognized as an item that could match an empty string. This meant that an
900        enclosing group might also not be so recognized, causing infinite looping
901        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
902        with the subject "ab", where knowledge that the repeated group can match
903        nothing is needed in order to break the loop.
905    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
906        exec(), but without supplying a callout function, matching went wrong.
908    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
909        leak if the size of the offset vector was greater than 30. When the vector
910        is smaller, the saved offsets during recursion go onto a local stack
911        vector, but for larger vectors malloc() is used. It was failing to free
912        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
913        error, in fact).
915    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
916        heapframe that is used only when UTF-8 support is enabled. This caused no
917        problem, but was untidy.
919    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
920        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
921        included within another project.
923    24. Steven Van Ingelgem's patches to add more options to the CMake support,
924        slightly modified by me:
926          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
927              not building pcregrep.
929          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
930              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
932    25. Forward references, both numeric and by name, in patterns that made use of
933        duplicate group numbers, could behave incorrectly or give incorrect errors,
934        because when scanning forward to find the reference group, PCRE was not
935        taking into account the duplicate group numbers. A pattern such as
936        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
938    26. Changed a few more instances of "const unsigned char *" to USPTR, making
939        the feature of a custom pointer more persuasive (as requested by a user).
941    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
942        pcretest.c, inside #ifndefs, because it seems they are sometimes already
943        pre-defined.
945    28. Added support for (*UTF8) at the start of a pattern.
947    29. Arrange for flags added by the "release type" setting in CMake to be shown
948        in the configuration summary.
951  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
952  ---------------------  ---------------------

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