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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.9 xx-xxx-09  Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
14    
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
23    
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
28    
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
34    
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
38    
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
46    
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
55    
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
59    
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
62    
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
68    
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
72    
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
77    
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
86    
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
90    
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
95    
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
102    
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
106    
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
109    
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
113    
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
116    
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
125    
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
129    
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
136    
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
140    
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
147    
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
151    
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
154    
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
157    
158    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.
161    
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).
165    
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
168    
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.
175    
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.
180    
181    
182    Version 8.12 15-Jan-2011
183    ------------------------
184    
185    1.  Fixed some typos in the markup of the man pages, and wrote a script that
186        checks for such things as part of the documentation building process.
187    
188    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
189        --match-limit and --recursion-limit options (added for 8.11). In
190        particular, this made one of the standard tests fail. (The integer value
191        went into the wrong half of a long int.)
192    
193    3.  If the --colour option was given to pcregrep with -v (invert match), it
194        did strange things, either producing crazy output, or crashing. It should,
195        of course, ignore a request for colour when reporting lines that do not
196        match.
197    
198    4.  Another pcregrep bug caused similar problems if --colour was specified with
199        -M (multiline) and the pattern match finished with a line ending.
200    
201    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
202        matched in multiline mode, the following line was shown as part of the
203        match. This seems wrong, so I have changed it.
204    
205    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
206        the check for further matches in the same line (so they could be coloured)
207        to overrun the end of the current line. If another match was found, it was
208        incorrectly shown (and then shown again when found in the next line).
209    
210    7.  If pcregrep was compiled under Windows, there was a reference to the
211        function pcregrep_exit() before it was defined. I am assuming this was
212        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
213        reported by a user. I've moved the definition above the reference.
214    
215    
216    Version 8.11 10-Dec-2010
217    ------------------------
218    
219    1.  (*THEN) was not working properly if there were untried alternatives prior
220        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
221        backtracked to try for "b" instead of moving to the next alternative branch
222        at the same level (in this case, to look for "c"). The Perl documentation
223        is clear that when (*THEN) is backtracked onto, it goes to the "next
224        alternative in the innermost enclosing group".
225    
226    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
227        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
228        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
229        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
230        (*THEN).
231    
232    3.  If \s appeared in a character class, it removed the VT character from
233        the class, even if it had been included by some previous item, for example
234        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
235        of \s, but is part of the POSIX "space" class.)
236    
237    4.  A partial match never returns an empty string (because you can always
238        match an empty string at the end of the subject); however the checking for
239        an empty string was starting at the "start of match" point. This has been
240        changed to the "earliest inspected character" point, because the returned
241        data for a partial match starts at this character. This means that, for
242        example, /(?<=abc)def/ gives a partial match for the subject "abc"
243        (previously it gave "no match").
244    
245    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
246        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
247        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
248        has an implication that the given string is incomplete (because a partial
249        match is preferred over a full match). For this reason, these items now
250        give a partial match in this situation. [Aside: previously, the one case
251        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
252        match rather than a full match, which was wrong by the old rules, but is
253        now correct.]
254    
255    6.  There was a bug in the handling of #-introduced comments, recognized when
256        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
257        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
258        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
259        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
260        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
261        places in pcre_compile().
262    
263    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
264        comments when looking ahead for named forward references to subpatterns,
265        the only newline sequence it recognized was NL. It now handles newlines
266        according to the set newline convention.
267    
268    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
269        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
270        cater for a lack of strerror(). These oversights have been fixed.
271    
272    9.  Added --match-limit and --recursion-limit to pcregrep.
273    
274    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
275    
276    11. When the -o option was used, pcregrep was setting a return code of 1, even
277        when matches were found, and --line-buffered was not being honoured.
278    
279    12. Added an optional parentheses number to the -o and --only-matching options
280        of pcregrep.
281    
282    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
283        can match an empty string. The code to do it in pcretest and pcredemo
284        needed fixing:
285    
286        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
287            only one byte after an empty string match just before CRLF (this case
288            just got forgotten; "any" and "anycrlf" were OK).
289    
290        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
291            mode when an empty string match preceded an ASCII character followed by
292            a non-ASCII character. (The code for advancing by one character rather
293            than one byte was nonsense.)
294    
295        (c) The pcredemo.c sample program did not have any code at all to handle
296            the cases when CRLF is a valid newline sequence.
297    
298    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
299        as a starting offset was within the subject string. There is now a new
300        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
301        negative or greater than the length of the string. In order to test this,
302        pcretest is extended to allow the setting of negative starting offsets.
303    
304    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
305        starting offset points to the beginning of a UTF-8 character was
306        unnecessarily clumsy. I tidied it up.
307    
308    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
309        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
310    
311    17. Nobody had reported that the --include_dir option, which was added in
312        release 7.7 should have been called --include-dir (hyphen, not underscore)
313        for compatibility with GNU grep. I have changed it to --include-dir, but
314        left --include_dir as an undocumented synonym, and the same for
315        --exclude-dir, though that is not available in GNU grep, at least as of
316        release 2.5.4.
317    
318    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
319        characters from a string of bytes) have been redefined so as not to use
320        loops, in order to improve performance in some environments. At the same
321        time, I abstracted some of the common code into auxiliary macros to save
322        repetition (this should not affect the compiled code).
323    
324    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
325        compile-time error is now given if \c is not followed by an ASCII
326        character, that is, a byte less than 128. (In EBCDIC mode, the code is
327        different, and any byte value is allowed.)
328    
329    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
330        START_OPTIMIZE option, which is now allowed at compile time - but just
331        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
332        to pcregrep and other applications that have no direct access to PCRE
333        options. The new /Y option in pcretest sets this option when calling
334        pcre_compile().
335    
336    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
337        back references. Groups containing recursive back references were forced to
338        be atomic by that change, but in the case of named groups, the amount of
339        memory required was incorrectly computed, leading to "Failed: internal
340        error: code overflow". This has been fixed.
341    
342    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
343        pcretest.c, to avoid build problems in some Borland environments.
344    
345    
346    Version 8.10 25-Jun-2010
347    ------------------------
348    
349    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
350        THEN.
351    
352    2.  (*ACCEPT) was not working when inside an atomic group.
353    
354    3.  Inside a character class, \B is treated as a literal by default, but
355        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
356        causes the error). The code is unchanged, but I tidied the documentation.
357    
358    4.  Inside a character class, PCRE always treated \R and \X as literals,
359        whereas Perl faults them if its -w option is set. I have changed PCRE so
360        that it faults them when PCRE_EXTRA is set.
361    
362    5.  Added support for \N, which always matches any character other than
363        newline. (It is the same as "." when PCRE_DOTALL is not set.)
364    
365    6.  When compiling pcregrep with newer versions of gcc which may have
366        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
367        declared with attribute warn_unused_result" were given. Just casting the
368        result to (void) does not stop the warnings; a more elaborate fudge is
369        needed. I've used a macro to implement this.
370    
371    7.  Minor change to pcretest.c to avoid a compiler warning.
372    
373    8.  Added four artifical Unicode properties to help with an option to make
374        \s etc use properties (see next item). The new properties are: Xan
375        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
376    
377    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
378        use Unicode properties. (*UCP) at the start of a pattern can be used to set
379        this option. Modified pcretest to add /W to test this facility. Added
380        REG_UCP to make it available via the POSIX interface.
381    
382    10. Added --line-buffered to pcregrep.
383    
384    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
385        studied, and the match started with a letter with a code point greater than
386        127 whose first byte was different to the first byte of the other case of
387        the letter, the other case of this starting letter was not recognized
388        (#976).
389    
390    12. If a pattern that was studied started with a repeated Unicode property
391        test, for example, \p{Nd}+, there was the theoretical possibility of
392        setting up an incorrect bitmap of starting bytes, but fortunately it could
393        not have actually happened in practice until change 8 above was made (it
394        added property types that matched character-matching opcodes).
395    
396    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
397        possible starting bytes for non-anchored patterns.
398    
399    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
400        \R, and also a number of cases that involve Unicode properties, both
401        explicit and implicit when PCRE_UCP is set.
402    
403    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
404        input, it could crash or give wrong results if characters with values
405        greater than 0xc0 were present in the subject string. (Detail: it assumed
406        UTF-8 input when processing these items.)
407    
408    16. Added a lot of (int) casts to avoid compiler warnings in systems where
409        size_t is 64-bit (#991).
410    
411    17. Added a check for running out of memory when PCRE is compiled with
412        --disable-stack-for-recursion (#990).
413    
414    18. If the last data line in a file for pcretest does not have a newline on
415        the end, a newline was missing in the output.
416    
417    19. The default pcre_chartables.c file recognizes only ASCII characters (values
418        less than 128) in its various bitmaps. However, there is a facility for
419        generating tables according to the current locale when PCRE is compiled. It
420        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
421        characters, are recognized by isspace() and therefore were getting set in
422        these tables, and indeed these tables seem to approximate to ISO 8859. This
423        caused a problem in UTF-8 mode when pcre_study() was used to create a list
424        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
425        which of course cannot start UTF-8 characters. I have changed the code so
426        that only real ASCII characters (less than 128) and the correct starting
427        bytes for UTF-8 encodings are set for characters greater than 127 when in
428        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
429        altogether.)
430    
431    20. Added the /T option to pcretest so as to be able to run tests with non-
432        standard character tables, thus making it possible to include the tests
433        used for 19 above in the standard set of tests.
434    
435    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
436        reference to a subpattern the other side of a comment that contains an
437        opening parenthesis caused either an internal compiling error, or a
438        reference to the wrong subpattern.
439    
440    
441    Version 8.02 19-Mar-2010
442    ------------------------
443    
444    1.  The Unicode data tables have been updated to Unicode 5.2.0.
445    
446    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
447        configured.
448    
449    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
450        original author of that file, following a query about its status.
451    
452    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
453        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
454    
455    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
456        quantifier applied to a forward-referencing subroutine call, could compile
457        incorrect code or give the error "internal error: previously-checked
458        referenced subpattern not found".
459    
460    6.  Both MS Visual Studio and Symbian OS have problems with initializing
461        variables to point to external functions. For these systems, therefore,
462        pcre_malloc etc. are now initialized to local functions that call the
463        relevant global functions.
464    
465    7.  There were two entries missing in the vectors called coptable and poptable
466        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
467        I've fixed the data, and added a kludgy way of testing at compile time that
468        the lengths are correct (equal to the number of opcodes).
469    
470    8.  Following on from 7, I added a similar kludge to check the length of the
471        eint vector in pcreposix.c.
472    
473    9.  Error texts for pcre_compile() are held as one long string to avoid too
474        much relocation at load time. To find a text, the string is searched,
475        counting zeros. There was no check for running off the end of the string,
476        which could happen if a new error number was added without updating the
477        string.
478    
479    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
480    
481    11. \K was not working if it appeared in an atomic group or in a group that
482        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
483        \K is "not well defined" if used in an assertion. PCRE now accepts it if
484        the assertion is positive, but not if it is negative.
485    
486    12. Change 11 fortuitously reduced the size of the stack frame used in the
487        "match()" function of pcre_exec.c by one pointer. Forthcoming
488        implementation of support for (*MARK) will need an extra pointer on the
489        stack; I have reserved it now, so that the stack frame size does not
490        decrease.
491    
492    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
493        item in branch that calls a recursion is a subroutine call - as in the
494        second branch in the above example - was incorrectly given the compile-
495        time error "recursive call could loop indefinitely" because pcre_compile()
496        was not correctly checking the subroutine for matching a non-empty string.
497    
498    14. The checks for overrunning compiling workspace could trigger after an
499        overrun had occurred. This is a "should never occur" error, but it can be
500        triggered by pathological patterns such as hundreds of nested parentheses.
501        The checks now trigger 100 bytes before the end of the workspace.
502    
503    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
504    
505    
506    Version 8.01 19-Jan-2010
507    ------------------------
508    
509    1.  If a pattern contained a conditional subpattern with only one branch (in
510        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
511        computed the wrong minimum data length (which is of course zero for such
512        subpatterns). This could cause incorrect "no match" results.
513    
514    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
515        the pattern is reset in the first branch, pcre_compile() failed with
516        "internal error: code overflow at offset...". This happened only when
517        the reset was to the original external option setting. (An optimization
518        abstracts leading options settings into an external setting, which was the
519        cause of this.)
520    
521    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
522        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
523        assertion pattern did not match (meaning that the assertion was true), it
524        was incorrectly treated as false if the SKIP had been reached during the
525        matching. This also applied to assertions used as conditions.
526    
527    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
528        assertion subpattern, including such a pattern used as a condition,
529        unpredictable results occurred, instead of the error return
530        PCRE_ERROR_DFA_UITEM.
531    
532    5.  The C++ GlobalReplace function was not working like Perl for the special
533        situation when an empty string is matched. It now does the fancy magic
534        stuff that is necessary.
535    
536    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
537        removed. (These were left over from very, very early versions of PCRE.)
538    
539    7.  Some cosmetic changes to the code to make life easier when compiling it
540        as part of something else:
541    
542        (a) Change DEBUG to PCRE_DEBUG.
543    
544        (b) In pcre_compile(), rename the member of the "branch_chain" structure
545            called "current" as "current_branch", to prevent a collision with the
546            Linux macro when compiled as a kernel module.
547    
548        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
549            prevent a collision with the Linux macro when compiled as a kernel
550            module.
551    
552    8.  In pcre_compile() there are some checks for integer overflows that used to
553        cast potentially large values to (double). This has been changed to that
554        when building, a check for int64_t is made, and if it is found, it is used
555        instead, thus avoiding the use of floating point arithmetic. (There is no
556        other use of FP in PCRE.) If int64_t is not found, the fallback is to
557        double.
558    
559    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
560        2005 (difference between two addresses compared to an unsigned value).
561    
562    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
563        custom one, because of the following reported problem in Windows:
564    
565          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
566              under Win32.
567          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
568              therefore missing the function definition.
569          - The compiler thus generates a "C" signature for the test function.
570          - The linker fails to find the "C" function.
571          - PCRE fails to configure if asked to do so against libbz2.
572    
573    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
574        messages were output:
575    
576          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
577          rerunning libtoolize, to keep the correct libtool macros in-tree.
578          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
579    
580        I have done both of these things.
581    
582    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
583        most of the time, it *can* run out if it is given a pattern that contains a
584        runaway infinite recursion. I updated the discussion in the pcrestack man
585        page.
586    
587    13. Now that we have gone to the x.xx style of version numbers, the minor
588        version may start with zero. Using 08 or 09 is a bad idea because users
589        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
590        interpreted as invalid octal numbers. I've updated the previous comment in
591        configure.ac, and also added a check that gives an error if 08 or 09 are
592        used.
593    
594    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
595        causing partial matching to fail when the end of the subject matched \W
596        in a UTF-8 pattern where \W was quantified with a minimum of 3.
597    
598    15. There were some discrepancies between the declarations in pcre_internal.h
599        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
600        their definitions. The declarations used "const uschar *" and the
601        definitions used USPTR. Even though USPTR is normally defined as "const
602        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
603        reported that: "This difference in casting confuses some C++ compilers, for
604        example, SunCC recognizes above declarations as different functions and
605        generates broken code for hbpcre." I have changed the declarations to use
606        USPTR.
607    
608    16. GNU libtool is named differently on some systems. The autogen.sh script now
609        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
610        (FreeBSD).
611    
612    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
613        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
614        comment: "Figure out how to create a longlong from a string: strtoll and
615        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
616        instance, but it only takes 2 args instead of 3!"
617    
618    18. A subtle bug concerned with back references has been fixed by a change of
619        specification, with a corresponding code fix. A pattern such as
620        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
621        refers, was giving matches when it shouldn't. For example, xa=xaaa would
622        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
623        same bug. Such groups have to be quantified to be useful, or contained
624        inside another quantified group. (If there's no repetition, the reference
625        can never match.) The problem arises because, having left the group and
626        moved on to the rest of the pattern, a later failure that backtracks into
627        the group uses the captured value from the final iteration of the group
628        rather than the correct earlier one. I have fixed this in PCRE by forcing
629        any group that contains a reference to itself to be an atomic group; that
630        is, there cannot be any backtracking into it once it has completed. This is
631        similar to recursive and subroutine calls.
632    
633    
634    Version 8.00 19-Oct-09
635    ----------------------
636    
637    1.  The table for translating pcre_compile() error codes into POSIX error codes
638        was out-of-date, and there was no check on the pcre_compile() error code
639        being within the table. This could lead to an OK return being given in
640        error.
641    
642    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
643        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
644        in a Windows environment.
645    
646    3.  The pcregrep --count option prints the count for each file even when it is
647        zero, as does GNU grep. However, pcregrep was also printing all files when
648        --files-with-matches was added. Now, when both options are given, it prints
649        counts only for those files that have at least one match. (GNU grep just
650        prints the file name in this circumstance, but including the count seems
651        more useful - otherwise, why use --count?) Also ensured that the
652        combination -clh just lists non-zero counts, with no names.
653    
654    4.  The long form of the pcregrep -F option was incorrectly implemented as
655        --fixed_strings instead of --fixed-strings. This is an incompatible change,
656        but it seems right to fix it, and I didn't think it was worth preserving
657        the old behaviour.
658    
659    5.  The command line items --regex=pattern and --regexp=pattern were not
660        recognized by pcregrep, which required --regex pattern or --regexp pattern
661        (with a space rather than an '='). The man page documented the '=' forms,
662        which are compatible with GNU grep; these now work.
663    
664    6.  No libpcreposix.pc file was created for pkg-config; there was just
665        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
666    
667    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
668        when UCP support is not needed, by modifying the Python script that
669        generates it from Unicode data files. This should not matter if the module
670        is correctly used as a library, but I received one complaint about 50K of
671        unwanted data. My guess is that the person linked everything into his
672        program rather than using a library. Anyway, it does no harm.
673    
674    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
675        was a minimum greater than 1 for a wide character in a possessive
676        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
677        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
678        character. Chaos in the form of incorrect output or a compiling loop could
679        result.
680    
681    9.  The restrictions on what a pattern can contain when partial matching is
682        requested for pcre_exec() have been removed. All patterns can now be
683        partially matched by this function. In addition, if there are at least two
684        slots in the offset vector, the offset of the earliest inspected character
685        for the match and the offset of the end of the subject are set in them when
686        PCRE_ERROR_PARTIAL is returned.
687    
688    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
689        synonymous with PCRE_PARTIAL, for backwards compatibility, and
690        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
691        and may be more useful for multi-segment matching.
692    
693    11. Partial matching with pcre_exec() is now more intuitive. A partial match
694        used to be given if ever the end of the subject was reached; now it is
695        given only if matching could not proceed because another character was
696        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
697        string "Z", which now yields "no match" instead of "partial match". In the
698        case of pcre_dfa_exec(), "no match" is given if every matching path for the
699        final character ended with (*FAIL).
700    
701    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
702        if the pattern had a "must contain" character that was already found in the
703        earlier partial match, unless partial matching was again requested. For
704        example, with the pattern /dog.(body)?/, the "must contain" character is
705        "g". If the first part-match was for the string "dog", restarting with
706        "sbody" failed. This bug has been fixed.
707    
708    13. The string returned by pcre_dfa_exec() after a partial match has been
709        changed so that it starts at the first inspected character rather than the
710        first character of the match. This makes a difference only if the pattern
711        starts with a lookbehind assertion or \b or \B (\K is not supported by
712        pcre_dfa_exec()). It's an incompatible change, but it makes the two
713        matching functions compatible, and I think it's the right thing to do.
714    
715    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
716        so that the demonstration program is easily available in environments where
717        PCRE has not been installed from source.
718    
719    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
720        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
721        library.
722    
723    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
724        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
725        is not the first non-POSIX option to be added. Clearly some people find
726        these options useful.
727    
728    17. If a caller to the POSIX matching function regexec() passes a non-zero
729        value for nmatch with a NULL value for pmatch, the value of
730        nmatch is forced to zero.
731    
732    18. RunGrepTest did not have a test for the availability of the -u option of
733        the diff command, as RunTest does. It now checks in the same way as
734        RunTest, and also checks for the -b option.
735    
736    19. If an odd number of negated classes containing just a single character
737        interposed, within parentheses, between a forward reference to a named
738        subpattern and the definition of the subpattern, compilation crashed with
739        an internal error, complaining that it could not find the referenced
740        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
741        [The bug was that it was starting one character too far in when skipping
742        over the character class, thus treating the ] as data rather than
743        terminating the class. This meant it could skip too much.]
744    
745    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
746        /g option in pcretest when the pattern contains \K, which makes it possible
747        to have an empty string match not at the start, even when the pattern is
748        anchored. Updated pcretest and pcredemo to use this option.
749    
750    21. If the maximum number of capturing subpatterns in a recursion was greater
751        than the maximum at the outer level, the higher number was returned, but
752        with unset values at the outer level. The correct (outer level) value is
753        now given.
754    
755    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
756        PCRE did not set those parentheses (unlike Perl). I have now found a way to
757        make it do so. The string so far is captured, making this feature
758        compatible with Perl.
759    
760    23. The tests have been re-organized, adding tests 11 and 12, to make it
761        possible to check the Perl 5.10 features against Perl 5.10.
762    
763    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
764        pattern matches a fixed length string. PCRE did not allow this; now it
765        does. Neither allows recursion.
766    
767    25. I finally figured out how to implement a request to provide the minimum
768        length of subject string that was needed in order to match a given pattern.
769        (It was back references and recursion that I had previously got hung up
770        on.) This code has now been added to pcre_study(); it finds a lower bound
771        to the length of subject needed. It is not necessarily the greatest lower
772        bound, but using it to avoid searching strings that are too short does give
773        some useful speed-ups. The value is available to calling programs via
774        pcre_fullinfo().
775    
776    26. While implementing 25, I discovered to my embarrassment that pcretest had
777        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
778        study optimizations had never been tested with that matching function.
779        Oops. What is worse, even when it was passed study data, there was a bug in
780        pcre_dfa_exec() that meant it never actually used it. Double oops. There
781        were also very few tests of studied patterns with pcre_dfa_exec().
782    
783    27. If (?| is used to create subpatterns with duplicate numbers, they are now
784        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
785        on the other side of the coin, they are no longer allowed to have different
786        names, because these cannot be distinguished in PCRE, and this has caused
787        confusion. (This is a difference from Perl.)
788    
789    28. When duplicate subpattern names are present (necessarily with different
790        numbers, as required by 27 above), and a test is made by name in a
791        conditional pattern, either for a subpattern having been matched, or for
792        recursion in such a pattern, all the associated numbered subpatterns are
793        tested, and the overall condition is true if the condition is true for any
794        one of them. This is the way Perl works, and is also more like the way
795        testing by number works.
796    
797    
798    Version 7.9 11-Apr-09
799  ---------------------  ---------------------
800    
801  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
802      (pcretest), all targets were linked against these libraries. This included      (pcretest), all targets were linked against these libraries. This included
803      libpcre, libpcreposix, and libpcrecpp, even though they do not use these      libpcre, libpcreposix, and libpcrecpp, even though they do not use these
804      libraries. This caused unwanted dependencies to be created. This problem      libraries. This caused unwanted dependencies to be created. This problem
805      has been fixed, and now only pcregrep is linked with bzlib/zlib and only      has been fixed, and now only pcregrep is linked with bzlib/zlib and only
806      pcretest is linked with readline.      pcretest is linked with readline.
807    
808  2.  The "typedef int BOOL" in pcre_internal.h that was included inside the  2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
809      "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been      "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
810      moved outside it again, because FALSE and TRUE are already defined in AIX,      moved outside it again, because FALSE and TRUE are already defined in AIX,
811      but BOOL is not.      but BOOL is not.
812    
813  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
814      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.
815    
816  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
817      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
818      lines. This is not true; no spaces are inserted. I have also clarified the      lines. This is not true; no spaces are inserted. I have also clarified the
819      wording for the --colour (or --color) option.      wording for the --colour (or --color) option.
820    
821  5.  In pcregrep, when --colour was used with -o, the list of matching strings  5.  In pcregrep, when --colour was used with -o, the list of matching strings
822      was not coloured; this is different to GNU grep, so I have changed it to be      was not coloured; this is different to GNU grep, so I have changed it to be
823      the same.      the same.
824    
825  6.  When --colo(u)r was used in pcregrep, only the first matching substring in  6.  When --colo(u)r was used in pcregrep, only the first matching substring in
826      each matching line was coloured. Now it goes on to look for further matches      each matching line was coloured. Now it goes on to look for further matches
827      of any of the test patterns, which is the same behaviour as GNU grep.      of any of the test patterns, which is the same behaviour as GNU grep.
828    
829  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
830      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
831      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
832      seems to be how GNU grep behaves.      seems to be how GNU grep behaves.
833    
834  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
835      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
836      correctly handled. The rule now is that both the assertion and what follows      correctly handled. The rule now is that both the assertion and what follows
837      in the first alternative must satisfy the test.      in the first alternative must satisfy the test.
838    
839  9.  If auto-callout was enabled in a pattern with a conditional group, PCRE  9.  If auto-callout was enabled in a pattern with a conditional group whose
840      could crash during matching.      condition was an assertion, PCRE could crash during matching, both with
841        pcre_exec() and pcre_dfa_exec().
842  10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was  
843      used for matching.  10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
844        used for matching.
845  11. Unicode property support in character classes was not working for  
846    11. Unicode property support in character classes was not working for
847      characters (bytes) greater than 127 when not in UTF-8 mode.      characters (bytes) greater than 127 when not in UTF-8 mode.
848    
849  12. Added the -M command line option to pcretest.  12. Added the -M command line option to pcretest.
850    
851  14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.  14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
852    
853  15. Added the PCRE_NO_START_OPTIMIZE match-time option.  15. Added the PCRE_NO_START_OPTIMIZE match-time option.
854    
855  16. Added comments and documentation about mis-use of no_arg in the C++  16. Added comments and documentation about mis-use of no_arg in the C++
856      wrapper.      wrapper.
857    
858  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
859      from Martin Jerabek that uses macro names for all relevant character and      from Martin Jerabek that uses macro names for all relevant character and
860      string constants.      string constants.
861    
862    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
863        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
864        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
865        these, but not everybody uses configure.
866    
867    19. A conditional group that had only one branch was not being correctly
868        recognized as an item that could match an empty string. This meant that an
869        enclosing group might also not be so recognized, causing infinite looping
870        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
871        with the subject "ab", where knowledge that the repeated group can match
872        nothing is needed in order to break the loop.
873    
874    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
875        exec(), but without supplying a callout function, matching went wrong.
876    
877    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
878        leak if the size of the offset vector was greater than 30. When the vector
879        is smaller, the saved offsets during recursion go onto a local stack
880        vector, but for larger vectors malloc() is used. It was failing to free
881        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
882        error, in fact).
883    
884    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
885        heapframe that is used only when UTF-8 support is enabled. This caused no
886        problem, but was untidy.
887    
888    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
889        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
890        included within another project.
891    
892    24. Steven Van Ingelgem's patches to add more options to the CMake support,
893        slightly modified by me:
894    
895          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
896              not building pcregrep.
897    
898          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
899              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
900    
901    25. Forward references, both numeric and by name, in patterns that made use of
902        duplicate group numbers, could behave incorrectly or give incorrect errors,
903        because when scanning forward to find the reference group, PCRE was not
904        taking into account the duplicate group numbers. A pattern such as
905        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
906    
907    26. Changed a few more instances of "const unsigned char *" to USPTR, making
908        the feature of a custom pointer more persuasive (as requested by a user).
909    
910    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
911        pcretest.c, inside #ifndefs, because it seems they are sometimes already
912        pre-defined.
913    
914    28. Added support for (*UTF8) at the start of a pattern.
915    
916    29. Arrange for flags added by the "release type" setting in CMake to be shown
917        in the configuration summary.
918    
919    
920  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
921  ---------------------  ---------------------

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