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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    
177    Version 8.12 15-Jan-2011
178    ------------------------
179    
180    1.  Fixed some typos in the markup of the man pages, and wrote a script that
181        checks for such things as part of the documentation building process.
182    
183    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
184        --match-limit and --recursion-limit options (added for 8.11). In
185        particular, this made one of the standard tests fail. (The integer value
186        went into the wrong half of a long int.)
187    
188    3.  If the --colour option was given to pcregrep with -v (invert match), it
189        did strange things, either producing crazy output, or crashing. It should,
190        of course, ignore a request for colour when reporting lines that do not
191        match.
192    
193    4.  Another pcregrep bug caused similar problems if --colour was specified with
194        -M (multiline) and the pattern match finished with a line ending.
195    
196    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
197        matched in multiline mode, the following line was shown as part of the
198        match. This seems wrong, so I have changed it.
199    
200    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
201        the check for further matches in the same line (so they could be coloured)
202        to overrun the end of the current line. If another match was found, it was
203        incorrectly shown (and then shown again when found in the next line).
204    
205    7.  If pcregrep was compiled under Windows, there was a reference to the
206        function pcregrep_exit() before it was defined. I am assuming this was
207        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
208        reported by a user. I've moved the definition above the reference.
209    
210    
211    Version 8.11 10-Dec-2010
212    ------------------------
213    
214    1.  (*THEN) was not working properly if there were untried alternatives prior
215        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
216        backtracked to try for "b" instead of moving to the next alternative branch
217        at the same level (in this case, to look for "c"). The Perl documentation
218        is clear that when (*THEN) is backtracked onto, it goes to the "next
219        alternative in the innermost enclosing group".
220    
221    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
222        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
223        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
224        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
225        (*THEN).
226    
227    3.  If \s appeared in a character class, it removed the VT character from
228        the class, even if it had been included by some previous item, for example
229        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
230        of \s, but is part of the POSIX "space" class.)
231    
232    4.  A partial match never returns an empty string (because you can always
233        match an empty string at the end of the subject); however the checking for
234        an empty string was starting at the "start of match" point. This has been
235        changed to the "earliest inspected character" point, because the returned
236        data for a partial match starts at this character. This means that, for
237        example, /(?<=abc)def/ gives a partial match for the subject "abc"
238        (previously it gave "no match").
239    
240    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
241        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
242        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
243        has an implication that the given string is incomplete (because a partial
244        match is preferred over a full match). For this reason, these items now
245        give a partial match in this situation. [Aside: previously, the one case
246        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
247        match rather than a full match, which was wrong by the old rules, but is
248        now correct.]
249    
250    6.  There was a bug in the handling of #-introduced comments, recognized when
251        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
252        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
253        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
254        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
255        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
256        places in pcre_compile().
257    
258    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
259        comments when looking ahead for named forward references to subpatterns,
260        the only newline sequence it recognized was NL. It now handles newlines
261        according to the set newline convention.
262    
263    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
264        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
265        cater for a lack of strerror(). These oversights have been fixed.
266    
267    9.  Added --match-limit and --recursion-limit to pcregrep.
268    
269    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
270    
271    11. When the -o option was used, pcregrep was setting a return code of 1, even
272        when matches were found, and --line-buffered was not being honoured.
273    
274    12. Added an optional parentheses number to the -o and --only-matching options
275        of pcregrep.
276    
277    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
278        can match an empty string. The code to do it in pcretest and pcredemo
279        needed fixing:
280    
281        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
282            only one byte after an empty string match just before CRLF (this case
283            just got forgotten; "any" and "anycrlf" were OK).
284    
285        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
286            mode when an empty string match preceded an ASCII character followed by
287            a non-ASCII character. (The code for advancing by one character rather
288            than one byte was nonsense.)
289    
290        (c) The pcredemo.c sample program did not have any code at all to handle
291            the cases when CRLF is a valid newline sequence.
292    
293    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
294        as a starting offset was within the subject string. There is now a new
295        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
296        negative or greater than the length of the string. In order to test this,
297        pcretest is extended to allow the setting of negative starting offsets.
298    
299    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
300        starting offset points to the beginning of a UTF-8 character was
301        unnecessarily clumsy. I tidied it up.
302    
303    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
304        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
305    
306    17. Nobody had reported that the --include_dir option, which was added in
307        release 7.7 should have been called --include-dir (hyphen, not underscore)
308        for compatibility with GNU grep. I have changed it to --include-dir, but
309        left --include_dir as an undocumented synonym, and the same for
310        --exclude-dir, though that is not available in GNU grep, at least as of
311        release 2.5.4.
312    
313    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
314        characters from a string of bytes) have been redefined so as not to use
315        loops, in order to improve performance in some environments. At the same
316        time, I abstracted some of the common code into auxiliary macros to save
317        repetition (this should not affect the compiled code).
318    
319    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
320        compile-time error is now given if \c is not followed by an ASCII
321        character, that is, a byte less than 128. (In EBCDIC mode, the code is
322        different, and any byte value is allowed.)
323    
324    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
325        START_OPTIMIZE option, which is now allowed at compile time - but just
326        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
327        to pcregrep and other applications that have no direct access to PCRE
328        options. The new /Y option in pcretest sets this option when calling
329        pcre_compile().
330    
331    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
332        back references. Groups containing recursive back references were forced to
333        be atomic by that change, but in the case of named groups, the amount of
334        memory required was incorrectly computed, leading to "Failed: internal
335        error: code overflow". This has been fixed.
336    
337    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
338        pcretest.c, to avoid build problems in some Borland environments.
339    
340    
341    Version 8.10 25-Jun-2010
342    ------------------------
343    
344    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
345        THEN.
346    
347    2.  (*ACCEPT) was not working when inside an atomic group.
348    
349    3.  Inside a character class, \B is treated as a literal by default, but
350        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
351        causes the error). The code is unchanged, but I tidied the documentation.
352    
353    4.  Inside a character class, PCRE always treated \R and \X as literals,
354        whereas Perl faults them if its -w option is set. I have changed PCRE so
355        that it faults them when PCRE_EXTRA is set.
356    
357    5.  Added support for \N, which always matches any character other than
358        newline. (It is the same as "." when PCRE_DOTALL is not set.)
359    
360    6.  When compiling pcregrep with newer versions of gcc which may have
361        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
362        declared with attribute warn_unused_result" were given. Just casting the
363        result to (void) does not stop the warnings; a more elaborate fudge is
364        needed. I've used a macro to implement this.
365    
366    7.  Minor change to pcretest.c to avoid a compiler warning.
367    
368    8.  Added four artifical Unicode properties to help with an option to make
369        \s etc use properties (see next item). The new properties are: Xan
370        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
371    
372    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
373        use Unicode properties. (*UCP) at the start of a pattern can be used to set
374        this option. Modified pcretest to add /W to test this facility. Added
375        REG_UCP to make it available via the POSIX interface.
376    
377    10. Added --line-buffered to pcregrep.
378    
379    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
380        studied, and the match started with a letter with a code point greater than
381        127 whose first byte was different to the first byte of the other case of
382        the letter, the other case of this starting letter was not recognized
383        (#976).
384    
385    12. If a pattern that was studied started with a repeated Unicode property
386        test, for example, \p{Nd}+, there was the theoretical possibility of
387        setting up an incorrect bitmap of starting bytes, but fortunately it could
388        not have actually happened in practice until change 8 above was made (it
389        added property types that matched character-matching opcodes).
390    
391    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
392        possible starting bytes for non-anchored patterns.
393    
394    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
395        \R, and also a number of cases that involve Unicode properties, both
396        explicit and implicit when PCRE_UCP is set.
397    
398    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
399        input, it could crash or give wrong results if characters with values
400        greater than 0xc0 were present in the subject string. (Detail: it assumed
401        UTF-8 input when processing these items.)
402    
403    16. Added a lot of (int) casts to avoid compiler warnings in systems where
404        size_t is 64-bit (#991).
405    
406    17. Added a check for running out of memory when PCRE is compiled with
407        --disable-stack-for-recursion (#990).
408    
409    18. If the last data line in a file for pcretest does not have a newline on
410        the end, a newline was missing in the output.
411    
412    19. The default pcre_chartables.c file recognizes only ASCII characters (values
413        less than 128) in its various bitmaps. However, there is a facility for
414        generating tables according to the current locale when PCRE is compiled. It
415        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
416        characters, are recognized by isspace() and therefore were getting set in
417        these tables, and indeed these tables seem to approximate to ISO 8859. This
418        caused a problem in UTF-8 mode when pcre_study() was used to create a list
419        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
420        which of course cannot start UTF-8 characters. I have changed the code so
421        that only real ASCII characters (less than 128) and the correct starting
422        bytes for UTF-8 encodings are set for characters greater than 127 when in
423        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
424        altogether.)
425    
426    20. Added the /T option to pcretest so as to be able to run tests with non-
427        standard character tables, thus making it possible to include the tests
428        used for 19 above in the standard set of tests.
429    
430    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
431        reference to a subpattern the other side of a comment that contains an
432        opening parenthesis caused either an internal compiling error, or a
433        reference to the wrong subpattern.
434    
435    
436    Version 8.02 19-Mar-2010
437    ------------------------
438    
439    1.  The Unicode data tables have been updated to Unicode 5.2.0.
440    
441    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
442        configured.
443    
444    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
445        original author of that file, following a query about its status.
446    
447    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
448        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
449    
450    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
451        quantifier applied to a forward-referencing subroutine call, could compile
452        incorrect code or give the error "internal error: previously-checked
453        referenced subpattern not found".
454    
455    6.  Both MS Visual Studio and Symbian OS have problems with initializing
456        variables to point to external functions. For these systems, therefore,
457        pcre_malloc etc. are now initialized to local functions that call the
458        relevant global functions.
459    
460    7.  There were two entries missing in the vectors called coptable and poptable
461        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
462        I've fixed the data, and added a kludgy way of testing at compile time that
463        the lengths are correct (equal to the number of opcodes).
464    
465    8.  Following on from 7, I added a similar kludge to check the length of the
466        eint vector in pcreposix.c.
467    
468    9.  Error texts for pcre_compile() are held as one long string to avoid too
469        much relocation at load time. To find a text, the string is searched,
470        counting zeros. There was no check for running off the end of the string,
471        which could happen if a new error number was added without updating the
472        string.
473    
474    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
475    
476    11. \K was not working if it appeared in an atomic group or in a group that
477        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
478        \K is "not well defined" if used in an assertion. PCRE now accepts it if
479        the assertion is positive, but not if it is negative.
480    
481    12. Change 11 fortuitously reduced the size of the stack frame used in the
482        "match()" function of pcre_exec.c by one pointer. Forthcoming
483        implementation of support for (*MARK) will need an extra pointer on the
484        stack; I have reserved it now, so that the stack frame size does not
485        decrease.
486    
487    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
488        item in branch that calls a recursion is a subroutine call - as in the
489        second branch in the above example - was incorrectly given the compile-
490        time error "recursive call could loop indefinitely" because pcre_compile()
491        was not correctly checking the subroutine for matching a non-empty string.
492    
493    14. The checks for overrunning compiling workspace could trigger after an
494        overrun had occurred. This is a "should never occur" error, but it can be
495        triggered by pathological patterns such as hundreds of nested parentheses.
496        The checks now trigger 100 bytes before the end of the workspace.
497    
498    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
499    
500    
501    Version 8.01 19-Jan-2010
502    ------------------------
503    
504    1.  If a pattern contained a conditional subpattern with only one branch (in
505        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
506        computed the wrong minimum data length (which is of course zero for such
507        subpatterns). This could cause incorrect "no match" results.
508    
509    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
510        the pattern is reset in the first branch, pcre_compile() failed with
511        "internal error: code overflow at offset...". This happened only when
512        the reset was to the original external option setting. (An optimization
513        abstracts leading options settings into an external setting, which was the
514        cause of this.)
515    
516    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
517        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
518        assertion pattern did not match (meaning that the assertion was true), it
519        was incorrectly treated as false if the SKIP had been reached during the
520        matching. This also applied to assertions used as conditions.
521    
522    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
523        assertion subpattern, including such a pattern used as a condition,
524        unpredictable results occurred, instead of the error return
525        PCRE_ERROR_DFA_UITEM.
526    
527    5.  The C++ GlobalReplace function was not working like Perl for the special
528        situation when an empty string is matched. It now does the fancy magic
529        stuff that is necessary.
530    
531    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
532        removed. (These were left over from very, very early versions of PCRE.)
533    
534    7.  Some cosmetic changes to the code to make life easier when compiling it
535        as part of something else:
536    
537        (a) Change DEBUG to PCRE_DEBUG.
538    
539        (b) In pcre_compile(), rename the member of the "branch_chain" structure
540            called "current" as "current_branch", to prevent a collision with the
541            Linux macro when compiled as a kernel module.
542    
543        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
544            prevent a collision with the Linux macro when compiled as a kernel
545            module.
546    
547    8.  In pcre_compile() there are some checks for integer overflows that used to
548        cast potentially large values to (double). This has been changed to that
549        when building, a check for int64_t is made, and if it is found, it is used
550        instead, thus avoiding the use of floating point arithmetic. (There is no
551        other use of FP in PCRE.) If int64_t is not found, the fallback is to
552        double.
553    
554    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
555        2005 (difference between two addresses compared to an unsigned value).
556    
557    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
558        custom one, because of the following reported problem in Windows:
559    
560          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
561              under Win32.
562          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
563              therefore missing the function definition.
564          - The compiler thus generates a "C" signature for the test function.
565          - The linker fails to find the "C" function.
566          - PCRE fails to configure if asked to do so against libbz2.
567    
568    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
569        messages were output:
570    
571          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
572          rerunning libtoolize, to keep the correct libtool macros in-tree.
573          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
574    
575        I have done both of these things.
576    
577    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
578        most of the time, it *can* run out if it is given a pattern that contains a
579        runaway infinite recursion. I updated the discussion in the pcrestack man
580        page.
581    
582    13. Now that we have gone to the x.xx style of version numbers, the minor
583        version may start with zero. Using 08 or 09 is a bad idea because users
584        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
585        interpreted as invalid octal numbers. I've updated the previous comment in
586        configure.ac, and also added a check that gives an error if 08 or 09 are
587        used.
588    
589    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
590        causing partial matching to fail when the end of the subject matched \W
591        in a UTF-8 pattern where \W was quantified with a minimum of 3.
592    
593    15. There were some discrepancies between the declarations in pcre_internal.h
594        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
595        their definitions. The declarations used "const uschar *" and the
596        definitions used USPTR. Even though USPTR is normally defined as "const
597        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
598        reported that: "This difference in casting confuses some C++ compilers, for
599        example, SunCC recognizes above declarations as different functions and
600        generates broken code for hbpcre." I have changed the declarations to use
601        USPTR.
602    
603    16. GNU libtool is named differently on some systems. The autogen.sh script now
604        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
605        (FreeBSD).
606    
607    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
608        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
609        comment: "Figure out how to create a longlong from a string: strtoll and
610        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
611        instance, but it only takes 2 args instead of 3!"
612    
613    18. A subtle bug concerned with back references has been fixed by a change of
614        specification, with a corresponding code fix. A pattern such as
615        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
616        refers, was giving matches when it shouldn't. For example, xa=xaaa would
617        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
618        same bug. Such groups have to be quantified to be useful, or contained
619        inside another quantified group. (If there's no repetition, the reference
620        can never match.) The problem arises because, having left the group and
621        moved on to the rest of the pattern, a later failure that backtracks into
622        the group uses the captured value from the final iteration of the group
623        rather than the correct earlier one. I have fixed this in PCRE by forcing
624        any group that contains a reference to itself to be an atomic group; that
625        is, there cannot be any backtracking into it once it has completed. This is
626        similar to recursive and subroutine calls.
627    
628    
629    Version 8.00 19-Oct-09
630    ----------------------
631    
632    1.  The table for translating pcre_compile() error codes into POSIX error codes
633        was out-of-date, and there was no check on the pcre_compile() error code
634        being within the table. This could lead to an OK return being given in
635        error.
636    
637    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
638        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
639        in a Windows environment.
640    
641    3.  The pcregrep --count option prints the count for each file even when it is
642        zero, as does GNU grep. However, pcregrep was also printing all files when
643        --files-with-matches was added. Now, when both options are given, it prints
644        counts only for those files that have at least one match. (GNU grep just
645        prints the file name in this circumstance, but including the count seems
646        more useful - otherwise, why use --count?) Also ensured that the
647        combination -clh just lists non-zero counts, with no names.
648    
649    4.  The long form of the pcregrep -F option was incorrectly implemented as
650        --fixed_strings instead of --fixed-strings. This is an incompatible change,
651        but it seems right to fix it, and I didn't think it was worth preserving
652        the old behaviour.
653    
654    5.  The command line items --regex=pattern and --regexp=pattern were not
655        recognized by pcregrep, which required --regex pattern or --regexp pattern
656        (with a space rather than an '='). The man page documented the '=' forms,
657        which are compatible with GNU grep; these now work.
658    
659    6.  No libpcreposix.pc file was created for pkg-config; there was just
660        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
661    
662    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
663        when UCP support is not needed, by modifying the Python script that
664        generates it from Unicode data files. This should not matter if the module
665        is correctly used as a library, but I received one complaint about 50K of
666        unwanted data. My guess is that the person linked everything into his
667        program rather than using a library. Anyway, it does no harm.
668    
669    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
670        was a minimum greater than 1 for a wide character in a possessive
671        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
672        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
673        character. Chaos in the form of incorrect output or a compiling loop could
674        result.
675    
676    9.  The restrictions on what a pattern can contain when partial matching is
677        requested for pcre_exec() have been removed. All patterns can now be
678        partially matched by this function. In addition, if there are at least two
679        slots in the offset vector, the offset of the earliest inspected character
680        for the match and the offset of the end of the subject are set in them when
681        PCRE_ERROR_PARTIAL is returned.
682    
683    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
684        synonymous with PCRE_PARTIAL, for backwards compatibility, and
685        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
686        and may be more useful for multi-segment matching.
687    
688    11. Partial matching with pcre_exec() is now more intuitive. A partial match
689        used to be given if ever the end of the subject was reached; now it is
690        given only if matching could not proceed because another character was
691        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
692        string "Z", which now yields "no match" instead of "partial match". In the
693        case of pcre_dfa_exec(), "no match" is given if every matching path for the
694        final character ended with (*FAIL).
695    
696    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
697        if the pattern had a "must contain" character that was already found in the
698        earlier partial match, unless partial matching was again requested. For
699        example, with the pattern /dog.(body)?/, the "must contain" character is
700        "g". If the first part-match was for the string "dog", restarting with
701        "sbody" failed. This bug has been fixed.
702    
703    13. The string returned by pcre_dfa_exec() after a partial match has been
704        changed so that it starts at the first inspected character rather than the
705        first character of the match. This makes a difference only if the pattern
706        starts with a lookbehind assertion or \b or \B (\K is not supported by
707        pcre_dfa_exec()). It's an incompatible change, but it makes the two
708        matching functions compatible, and I think it's the right thing to do.
709    
710    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
711        so that the demonstration program is easily available in environments where
712        PCRE has not been installed from source.
713    
714    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
715        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
716        library.
717    
718    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
719        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
720        is not the first non-POSIX option to be added. Clearly some people find
721        these options useful.
722    
723    17. If a caller to the POSIX matching function regexec() passes a non-zero
724        value for nmatch with a NULL value for pmatch, the value of
725        nmatch is forced to zero.
726    
727    18. RunGrepTest did not have a test for the availability of the -u option of
728        the diff command, as RunTest does. It now checks in the same way as
729        RunTest, and also checks for the -b option.
730    
731    19. If an odd number of negated classes containing just a single character
732        interposed, within parentheses, between a forward reference to a named
733        subpattern and the definition of the subpattern, compilation crashed with
734        an internal error, complaining that it could not find the referenced
735        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
736        [The bug was that it was starting one character too far in when skipping
737        over the character class, thus treating the ] as data rather than
738        terminating the class. This meant it could skip too much.]
739    
740    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
741        /g option in pcretest when the pattern contains \K, which makes it possible
742        to have an empty string match not at the start, even when the pattern is
743        anchored. Updated pcretest and pcredemo to use this option.
744    
745    21. If the maximum number of capturing subpatterns in a recursion was greater
746        than the maximum at the outer level, the higher number was returned, but
747        with unset values at the outer level. The correct (outer level) value is
748        now given.
749    
750    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
751        PCRE did not set those parentheses (unlike Perl). I have now found a way to
752        make it do so. The string so far is captured, making this feature
753        compatible with Perl.
754    
755    23. The tests have been re-organized, adding tests 11 and 12, to make it
756        possible to check the Perl 5.10 features against Perl 5.10.
757    
758    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
759        pattern matches a fixed length string. PCRE did not allow this; now it
760        does. Neither allows recursion.
761    
762    25. I finally figured out how to implement a request to provide the minimum
763        length of subject string that was needed in order to match a given pattern.
764        (It was back references and recursion that I had previously got hung up
765        on.) This code has now been added to pcre_study(); it finds a lower bound
766        to the length of subject needed. It is not necessarily the greatest lower
767        bound, but using it to avoid searching strings that are too short does give
768        some useful speed-ups. The value is available to calling programs via
769        pcre_fullinfo().
770    
771    26. While implementing 25, I discovered to my embarrassment that pcretest had
772        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
773        study optimizations had never been tested with that matching function.
774        Oops. What is worse, even when it was passed study data, there was a bug in
775        pcre_dfa_exec() that meant it never actually used it. Double oops. There
776        were also very few tests of studied patterns with pcre_dfa_exec().
777    
778    27. If (?| is used to create subpatterns with duplicate numbers, they are now
779        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
780        on the other side of the coin, they are no longer allowed to have different
781        names, because these cannot be distinguished in PCRE, and this has caused
782        confusion. (This is a difference from Perl.)
783    
784    28. When duplicate subpattern names are present (necessarily with different
785        numbers, as required by 27 above), and a test is made by name in a
786        conditional pattern, either for a subpattern having been matched, or for
787        recursion in such a pattern, all the associated numbered subpatterns are
788        tested, and the overall condition is true if the condition is true for any
789        one of them. This is the way Perl works, and is also more like the way
790        testing by number works.
791    
792    
793    Version 7.9 11-Apr-09
794  ---------------------  ---------------------
795    
796  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
797      (pcretest), all targets were linked against these libraries. This included      (pcretest), all targets were linked against these libraries. This included
798      libpcre, libpcreposix, and libpcrecpp, even though they do not use these      libpcre, libpcreposix, and libpcrecpp, even though they do not use these
799      libraries. This caused unwanted dependencies to be created. This problem      libraries. This caused unwanted dependencies to be created. This problem
800      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
801      pcretest is linked with readline.      pcretest is linked with readline.
802    
803  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
804      "#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
805      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,
806      but BOOL is not.      but BOOL is not.
807    
808  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
809      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.
810    
811  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
812      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
813      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
814      wording for the --colour (or --color) option.      wording for the --colour (or --color) option.
815    
816  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
817      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
818      the same.      the same.
819    
820  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
821      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
822      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.
823    
824  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
825      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
826      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
827      seems to be how GNU grep behaves.      seems to be how GNU grep behaves.
828    
829  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
830      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
831      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
832      in the first alternative must satisfy the test.      in the first alternative must satisfy the test.
833    
834  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
835      could crash during matching.      condition was an assertion, PCRE could crash during matching, both with
836        pcre_exec() and pcre_dfa_exec().
837  10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was  
838      used for matching.  10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
839        used for matching.
840  11. Unicode property support in character classes was not working for  
841    11. Unicode property support in character classes was not working for
842      characters (bytes) greater than 127 when not in UTF-8 mode.      characters (bytes) greater than 127 when not in UTF-8 mode.
843    
844  12. Added the -M command line option to pcretest.  12. Added the -M command line option to pcretest.
845    
846    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
847    
848    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
849    
850    16. Added comments and documentation about mis-use of no_arg in the C++
851        wrapper.
852    
853    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
854        from Martin Jerabek that uses macro names for all relevant character and
855        string constants.
856    
857    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
858        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
859        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
860        these, but not everybody uses configure.
861    
862    19. A conditional group that had only one branch was not being correctly
863        recognized as an item that could match an empty string. This meant that an
864        enclosing group might also not be so recognized, causing infinite looping
865        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
866        with the subject "ab", where knowledge that the repeated group can match
867        nothing is needed in order to break the loop.
868    
869    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
870        exec(), but without supplying a callout function, matching went wrong.
871    
872    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
873        leak if the size of the offset vector was greater than 30. When the vector
874        is smaller, the saved offsets during recursion go onto a local stack
875        vector, but for larger vectors malloc() is used. It was failing to free
876        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
877        error, in fact).
878    
879    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
880        heapframe that is used only when UTF-8 support is enabled. This caused no
881        problem, but was untidy.
882    
883    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
884        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
885        included within another project.
886    
887    24. Steven Van Ingelgem's patches to add more options to the CMake support,
888        slightly modified by me:
889    
890          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
891              not building pcregrep.
892    
893          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
894              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
895    
896    25. Forward references, both numeric and by name, in patterns that made use of
897        duplicate group numbers, could behave incorrectly or give incorrect errors,
898        because when scanning forward to find the reference group, PCRE was not
899        taking into account the duplicate group numbers. A pattern such as
900        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
901    
902    26. Changed a few more instances of "const unsigned char *" to USPTR, making
903        the feature of a custom pointer more persuasive (as requested by a user).
904    
905    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
906        pcretest.c, inside #ifndefs, because it seems they are sometimes already
907        pre-defined.
908    
909    28. Added support for (*UTF8) at the start of a pattern.
910    
911    29. Arrange for flags added by the "release type" setting in CMake to be shown
912        in the configuration summary.
913    
914    
915  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
916  ---------------------  ---------------------

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