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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.0 02 Jul-08  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    
118    Version 8.12 15-Jan-2011
119    ------------------------
120    
121    1.  Fixed some typos in the markup of the man pages, and wrote a script that
122        checks for such things as part of the documentation building process.
123    
124    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
125        --match-limit and --recursion-limit options (added for 8.11). In
126        particular, this made one of the standard tests fail. (The integer value
127        went into the wrong half of a long int.)
128    
129    3.  If the --colour option was given to pcregrep with -v (invert match), it
130        did strange things, either producing crazy output, or crashing. It should,
131        of course, ignore a request for colour when reporting lines that do not
132        match.
133    
134    4.  Another pcregrep bug caused similar problems if --colour was specified with
135        -M (multiline) and the pattern match finished with a line ending.
136    
137    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
138        matched in multiline mode, the following line was shown as part of the
139        match. This seems wrong, so I have changed it.
140    
141    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
142        the check for further matches in the same line (so they could be coloured)
143        to overrun the end of the current line. If another match was found, it was
144        incorrectly shown (and then shown again when found in the next line).
145    
146    7.  If pcregrep was compiled under Windows, there was a reference to the
147        function pcregrep_exit() before it was defined. I am assuming this was
148        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
149        reported by a user. I've moved the definition above the reference.
150    
151    
152    Version 8.11 10-Dec-2010
153    ------------------------
154    
155    1.  (*THEN) was not working properly if there were untried alternatives prior
156        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
157        backtracked to try for "b" instead of moving to the next alternative branch
158        at the same level (in this case, to look for "c"). The Perl documentation
159        is clear that when (*THEN) is backtracked onto, it goes to the "next
160        alternative in the innermost enclosing group".
161    
162    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
163        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
164        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
165        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
166        (*THEN).
167    
168    3.  If \s appeared in a character class, it removed the VT character from
169        the class, even if it had been included by some previous item, for example
170        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
171        of \s, but is part of the POSIX "space" class.)
172    
173    4.  A partial match never returns an empty string (because you can always
174        match an empty string at the end of the subject); however the checking for
175        an empty string was starting at the "start of match" point. This has been
176        changed to the "earliest inspected character" point, because the returned
177        data for a partial match starts at this character. This means that, for
178        example, /(?<=abc)def/ gives a partial match for the subject "abc"
179        (previously it gave "no match").
180    
181    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
182        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
183        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
184        has an implication that the given string is incomplete (because a partial
185        match is preferred over a full match). For this reason, these items now
186        give a partial match in this situation. [Aside: previously, the one case
187        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
188        match rather than a full match, which was wrong by the old rules, but is
189        now correct.]
190    
191    6.  There was a bug in the handling of #-introduced comments, recognized when
192        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
193        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
194        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
195        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
196        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
197        places in pcre_compile().
198    
199    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
200        comments when looking ahead for named forward references to subpatterns,
201        the only newline sequence it recognized was NL. It now handles newlines
202        according to the set newline convention.
203    
204    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
205        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
206        cater for a lack of strerror(). These oversights have been fixed.
207    
208    9.  Added --match-limit and --recursion-limit to pcregrep.
209    
210    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
211    
212    11. When the -o option was used, pcregrep was setting a return code of 1, even
213        when matches were found, and --line-buffered was not being honoured.
214    
215    12. Added an optional parentheses number to the -o and --only-matching options
216        of pcregrep.
217    
218    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
219        can match an empty string. The code to do it in pcretest and pcredemo
220        needed fixing:
221    
222        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
223            only one byte after an empty string match just before CRLF (this case
224            just got forgotten; "any" and "anycrlf" were OK).
225    
226        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
227            mode when an empty string match preceded an ASCII character followed by
228            a non-ASCII character. (The code for advancing by one character rather
229            than one byte was nonsense.)
230    
231        (c) The pcredemo.c sample program did not have any code at all to handle
232            the cases when CRLF is a valid newline sequence.
233    
234    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
235        as a starting offset was within the subject string. There is now a new
236        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
237        negative or greater than the length of the string. In order to test this,
238        pcretest is extended to allow the setting of negative starting offsets.
239    
240    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
241        starting offset points to the beginning of a UTF-8 character was
242        unnecessarily clumsy. I tidied it up.
243    
244    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
245        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
246    
247    17. Nobody had reported that the --include_dir option, which was added in
248        release 7.7 should have been called --include-dir (hyphen, not underscore)
249        for compatibility with GNU grep. I have changed it to --include-dir, but
250        left --include_dir as an undocumented synonym, and the same for
251        --exclude-dir, though that is not available in GNU grep, at least as of
252        release 2.5.4.
253    
254    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
255        characters from a string of bytes) have been redefined so as not to use
256        loops, in order to improve performance in some environments. At the same
257        time, I abstracted some of the common code into auxiliary macros to save
258        repetition (this should not affect the compiled code).
259    
260    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
261        compile-time error is now given if \c is not followed by an ASCII
262        character, that is, a byte less than 128. (In EBCDIC mode, the code is
263        different, and any byte value is allowed.)
264    
265    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
266        START_OPTIMIZE option, which is now allowed at compile time - but just
267        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
268        to pcregrep and other applications that have no direct access to PCRE
269        options. The new /Y option in pcretest sets this option when calling
270        pcre_compile().
271    
272    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
273        back references. Groups containing recursive back references were forced to
274        be atomic by that change, but in the case of named groups, the amount of
275        memory required was incorrectly computed, leading to "Failed: internal
276        error: code overflow". This has been fixed.
277    
278    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
279        pcretest.c, to avoid build problems in some Borland environments.
280    
281    
282    Version 8.10 25-Jun-2010
283    ------------------------
284    
285    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
286        THEN.
287    
288    2.  (*ACCEPT) was not working when inside an atomic group.
289    
290    3.  Inside a character class, \B is treated as a literal by default, but
291        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
292        causes the error). The code is unchanged, but I tidied the documentation.
293    
294    4.  Inside a character class, PCRE always treated \R and \X as literals,
295        whereas Perl faults them if its -w option is set. I have changed PCRE so
296        that it faults them when PCRE_EXTRA is set.
297    
298    5.  Added support for \N, which always matches any character other than
299        newline. (It is the same as "." when PCRE_DOTALL is not set.)
300    
301    6.  When compiling pcregrep with newer versions of gcc which may have
302        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
303        declared with attribute warn_unused_result" were given. Just casting the
304        result to (void) does not stop the warnings; a more elaborate fudge is
305        needed. I've used a macro to implement this.
306    
307    7.  Minor change to pcretest.c to avoid a compiler warning.
308    
309    8.  Added four artifical Unicode properties to help with an option to make
310        \s etc use properties (see next item). The new properties are: Xan
311        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
312    
313    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
314        use Unicode properties. (*UCP) at the start of a pattern can be used to set
315        this option. Modified pcretest to add /W to test this facility. Added
316        REG_UCP to make it available via the POSIX interface.
317    
318    10. Added --line-buffered to pcregrep.
319    
320    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
321        studied, and the match started with a letter with a code point greater than
322        127 whose first byte was different to the first byte of the other case of
323        the letter, the other case of this starting letter was not recognized
324        (#976).
325    
326    12. If a pattern that was studied started with a repeated Unicode property
327        test, for example, \p{Nd}+, there was the theoretical possibility of
328        setting up an incorrect bitmap of starting bytes, but fortunately it could
329        not have actually happened in practice until change 8 above was made (it
330        added property types that matched character-matching opcodes).
331    
332    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
333        possible starting bytes for non-anchored patterns.
334    
335    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
336        \R, and also a number of cases that involve Unicode properties, both
337        explicit and implicit when PCRE_UCP is set.
338    
339    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
340        input, it could crash or give wrong results if characters with values
341        greater than 0xc0 were present in the subject string. (Detail: it assumed
342        UTF-8 input when processing these items.)
343    
344    16. Added a lot of (int) casts to avoid compiler warnings in systems where
345        size_t is 64-bit (#991).
346    
347    17. Added a check for running out of memory when PCRE is compiled with
348        --disable-stack-for-recursion (#990).
349    
350    18. If the last data line in a file for pcretest does not have a newline on
351        the end, a newline was missing in the output.
352    
353    19. The default pcre_chartables.c file recognizes only ASCII characters (values
354        less than 128) in its various bitmaps. However, there is a facility for
355        generating tables according to the current locale when PCRE is compiled. It
356        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
357        characters, are recognized by isspace() and therefore were getting set in
358        these tables, and indeed these tables seem to approximate to ISO 8859. This
359        caused a problem in UTF-8 mode when pcre_study() was used to create a list
360        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
361        which of course cannot start UTF-8 characters. I have changed the code so
362        that only real ASCII characters (less than 128) and the correct starting
363        bytes for UTF-8 encodings are set for characters greater than 127 when in
364        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
365        altogether.)
366    
367    20. Added the /T option to pcretest so as to be able to run tests with non-
368        standard character tables, thus making it possible to include the tests
369        used for 19 above in the standard set of tests.
370    
371    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
372        reference to a subpattern the other side of a comment that contains an
373        opening parenthesis caused either an internal compiling error, or a
374        reference to the wrong subpattern.
375    
376    
377    Version 8.02 19-Mar-2010
378    ------------------------
379    
380    1.  The Unicode data tables have been updated to Unicode 5.2.0.
381    
382    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
383        configured.
384    
385    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
386        original author of that file, following a query about its status.
387    
388    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
389        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
390    
391    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
392        quantifier applied to a forward-referencing subroutine call, could compile
393        incorrect code or give the error "internal error: previously-checked
394        referenced subpattern not found".
395    
396    6.  Both MS Visual Studio and Symbian OS have problems with initializing
397        variables to point to external functions. For these systems, therefore,
398        pcre_malloc etc. are now initialized to local functions that call the
399        relevant global functions.
400    
401    7.  There were two entries missing in the vectors called coptable and poptable
402        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
403        I've fixed the data, and added a kludgy way of testing at compile time that
404        the lengths are correct (equal to the number of opcodes).
405    
406    8.  Following on from 7, I added a similar kludge to check the length of the
407        eint vector in pcreposix.c.
408    
409    9.  Error texts for pcre_compile() are held as one long string to avoid too
410        much relocation at load time. To find a text, the string is searched,
411        counting zeros. There was no check for running off the end of the string,
412        which could happen if a new error number was added without updating the
413        string.
414    
415    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
416    
417    11. \K was not working if it appeared in an atomic group or in a group that
418        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
419        \K is "not well defined" if used in an assertion. PCRE now accepts it if
420        the assertion is positive, but not if it is negative.
421    
422    12. Change 11 fortuitously reduced the size of the stack frame used in the
423        "match()" function of pcre_exec.c by one pointer. Forthcoming
424        implementation of support for (*MARK) will need an extra pointer on the
425        stack; I have reserved it now, so that the stack frame size does not
426        decrease.
427    
428    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
429        item in branch that calls a recursion is a subroutine call - as in the
430        second branch in the above example - was incorrectly given the compile-
431        time error "recursive call could loop indefinitely" because pcre_compile()
432        was not correctly checking the subroutine for matching a non-empty string.
433    
434    14. The checks for overrunning compiling workspace could trigger after an
435        overrun had occurred. This is a "should never occur" error, but it can be
436        triggered by pathological patterns such as hundreds of nested parentheses.
437        The checks now trigger 100 bytes before the end of the workspace.
438    
439    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
440    
441    
442    Version 8.01 19-Jan-2010
443    ------------------------
444    
445    1.  If a pattern contained a conditional subpattern with only one branch (in
446        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
447        computed the wrong minimum data length (which is of course zero for such
448        subpatterns). This could cause incorrect "no match" results.
449    
450    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
451        the pattern is reset in the first branch, pcre_compile() failed with
452        "internal error: code overflow at offset...". This happened only when
453        the reset was to the original external option setting. (An optimization
454        abstracts leading options settings into an external setting, which was the
455        cause of this.)
456    
457    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
458        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
459        assertion pattern did not match (meaning that the assertion was true), it
460        was incorrectly treated as false if the SKIP had been reached during the
461        matching. This also applied to assertions used as conditions.
462    
463    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
464        assertion subpattern, including such a pattern used as a condition,
465        unpredictable results occurred, instead of the error return
466        PCRE_ERROR_DFA_UITEM.
467    
468    5.  The C++ GlobalReplace function was not working like Perl for the special
469        situation when an empty string is matched. It now does the fancy magic
470        stuff that is necessary.
471    
472    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
473        removed. (These were left over from very, very early versions of PCRE.)
474    
475    7.  Some cosmetic changes to the code to make life easier when compiling it
476        as part of something else:
477    
478        (a) Change DEBUG to PCRE_DEBUG.
479    
480        (b) In pcre_compile(), rename the member of the "branch_chain" structure
481            called "current" as "current_branch", to prevent a collision with the
482            Linux macro when compiled as a kernel module.
483    
484        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
485            prevent a collision with the Linux macro when compiled as a kernel
486            module.
487    
488    8.  In pcre_compile() there are some checks for integer overflows that used to
489        cast potentially large values to (double). This has been changed to that
490        when building, a check for int64_t is made, and if it is found, it is used
491        instead, thus avoiding the use of floating point arithmetic. (There is no
492        other use of FP in PCRE.) If int64_t is not found, the fallback is to
493        double.
494    
495    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
496        2005 (difference between two addresses compared to an unsigned value).
497    
498    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
499        custom one, because of the following reported problem in Windows:
500    
501          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
502              under Win32.
503          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
504              therefore missing the function definition.
505          - The compiler thus generates a "C" signature for the test function.
506          - The linker fails to find the "C" function.
507          - PCRE fails to configure if asked to do so against libbz2.
508    
509    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
510        messages were output:
511    
512          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
513          rerunning libtoolize, to keep the correct libtool macros in-tree.
514          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
515    
516        I have done both of these things.
517    
518    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
519        most of the time, it *can* run out if it is given a pattern that contains a
520        runaway infinite recursion. I updated the discussion in the pcrestack man
521        page.
522    
523    13. Now that we have gone to the x.xx style of version numbers, the minor
524        version may start with zero. Using 08 or 09 is a bad idea because users
525        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
526        interpreted as invalid octal numbers. I've updated the previous comment in
527        configure.ac, and also added a check that gives an error if 08 or 09 are
528        used.
529    
530    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
531        causing partial matching to fail when the end of the subject matched \W
532        in a UTF-8 pattern where \W was quantified with a minimum of 3.
533    
534    15. There were some discrepancies between the declarations in pcre_internal.h
535        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
536        their definitions. The declarations used "const uschar *" and the
537        definitions used USPTR. Even though USPTR is normally defined as "const
538        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
539        reported that: "This difference in casting confuses some C++ compilers, for
540        example, SunCC recognizes above declarations as different functions and
541        generates broken code for hbpcre." I have changed the declarations to use
542        USPTR.
543    
544    16. GNU libtool is named differently on some systems. The autogen.sh script now
545        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
546        (FreeBSD).
547    
548    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
549        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
550        comment: "Figure out how to create a longlong from a string: strtoll and
551        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
552        instance, but it only takes 2 args instead of 3!"
553    
554    18. A subtle bug concerned with back references has been fixed by a change of
555        specification, with a corresponding code fix. A pattern such as
556        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
557        refers, was giving matches when it shouldn't. For example, xa=xaaa would
558        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
559        same bug. Such groups have to be quantified to be useful, or contained
560        inside another quantified group. (If there's no repetition, the reference
561        can never match.) The problem arises because, having left the group and
562        moved on to the rest of the pattern, a later failure that backtracks into
563        the group uses the captured value from the final iteration of the group
564        rather than the correct earlier one. I have fixed this in PCRE by forcing
565        any group that contains a reference to itself to be an atomic group; that
566        is, there cannot be any backtracking into it once it has completed. This is
567        similar to recursive and subroutine calls.
568    
569    
570    Version 8.00 19-Oct-09
571    ----------------------
572    
573    1.  The table for translating pcre_compile() error codes into POSIX error codes
574        was out-of-date, and there was no check on the pcre_compile() error code
575        being within the table. This could lead to an OK return being given in
576        error.
577    
578    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
579        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
580        in a Windows environment.
581    
582    3.  The pcregrep --count option prints the count for each file even when it is
583        zero, as does GNU grep. However, pcregrep was also printing all files when
584        --files-with-matches was added. Now, when both options are given, it prints
585        counts only for those files that have at least one match. (GNU grep just
586        prints the file name in this circumstance, but including the count seems
587        more useful - otherwise, why use --count?) Also ensured that the
588        combination -clh just lists non-zero counts, with no names.
589    
590    4.  The long form of the pcregrep -F option was incorrectly implemented as
591        --fixed_strings instead of --fixed-strings. This is an incompatible change,
592        but it seems right to fix it, and I didn't think it was worth preserving
593        the old behaviour.
594    
595    5.  The command line items --regex=pattern and --regexp=pattern were not
596        recognized by pcregrep, which required --regex pattern or --regexp pattern
597        (with a space rather than an '='). The man page documented the '=' forms,
598        which are compatible with GNU grep; these now work.
599    
600    6.  No libpcreposix.pc file was created for pkg-config; there was just
601        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
602    
603    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
604        when UCP support is not needed, by modifying the Python script that
605        generates it from Unicode data files. This should not matter if the module
606        is correctly used as a library, but I received one complaint about 50K of
607        unwanted data. My guess is that the person linked everything into his
608        program rather than using a library. Anyway, it does no harm.
609    
610    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
611        was a minimum greater than 1 for a wide character in a possessive
612        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
613        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
614        character. Chaos in the form of incorrect output or a compiling loop could
615        result.
616    
617    9.  The restrictions on what a pattern can contain when partial matching is
618        requested for pcre_exec() have been removed. All patterns can now be
619        partially matched by this function. In addition, if there are at least two
620        slots in the offset vector, the offset of the earliest inspected character
621        for the match and the offset of the end of the subject are set in them when
622        PCRE_ERROR_PARTIAL is returned.
623    
624    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
625        synonymous with PCRE_PARTIAL, for backwards compatibility, and
626        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
627        and may be more useful for multi-segment matching.
628    
629    11. Partial matching with pcre_exec() is now more intuitive. A partial match
630        used to be given if ever the end of the subject was reached; now it is
631        given only if matching could not proceed because another character was
632        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
633        string "Z", which now yields "no match" instead of "partial match". In the
634        case of pcre_dfa_exec(), "no match" is given if every matching path for the
635        final character ended with (*FAIL).
636    
637    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
638        if the pattern had a "must contain" character that was already found in the
639        earlier partial match, unless partial matching was again requested. For
640        example, with the pattern /dog.(body)?/, the "must contain" character is
641        "g". If the first part-match was for the string "dog", restarting with
642        "sbody" failed. This bug has been fixed.
643    
644    13. The string returned by pcre_dfa_exec() after a partial match has been
645        changed so that it starts at the first inspected character rather than the
646        first character of the match. This makes a difference only if the pattern
647        starts with a lookbehind assertion or \b or \B (\K is not supported by
648        pcre_dfa_exec()). It's an incompatible change, but it makes the two
649        matching functions compatible, and I think it's the right thing to do.
650    
651    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
652        so that the demonstration program is easily available in environments where
653        PCRE has not been installed from source.
654    
655    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
656        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
657        library.
658    
659    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
660        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
661        is not the first non-POSIX option to be added. Clearly some people find
662        these options useful.
663    
664    17. If a caller to the POSIX matching function regexec() passes a non-zero
665        value for nmatch with a NULL value for pmatch, the value of
666        nmatch is forced to zero.
667    
668    18. RunGrepTest did not have a test for the availability of the -u option of
669        the diff command, as RunTest does. It now checks in the same way as
670        RunTest, and also checks for the -b option.
671    
672    19. If an odd number of negated classes containing just a single character
673        interposed, within parentheses, between a forward reference to a named
674        subpattern and the definition of the subpattern, compilation crashed with
675        an internal error, complaining that it could not find the referenced
676        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
677        [The bug was that it was starting one character too far in when skipping
678        over the character class, thus treating the ] as data rather than
679        terminating the class. This meant it could skip too much.]
680    
681    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
682        /g option in pcretest when the pattern contains \K, which makes it possible
683        to have an empty string match not at the start, even when the pattern is
684        anchored. Updated pcretest and pcredemo to use this option.
685    
686    21. If the maximum number of capturing subpatterns in a recursion was greater
687        than the maximum at the outer level, the higher number was returned, but
688        with unset values at the outer level. The correct (outer level) value is
689        now given.
690    
691    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
692        PCRE did not set those parentheses (unlike Perl). I have now found a way to
693        make it do so. The string so far is captured, making this feature
694        compatible with Perl.
695    
696    23. The tests have been re-organized, adding tests 11 and 12, to make it
697        possible to check the Perl 5.10 features against Perl 5.10.
698    
699    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
700        pattern matches a fixed length string. PCRE did not allow this; now it
701        does. Neither allows recursion.
702    
703    25. I finally figured out how to implement a request to provide the minimum
704        length of subject string that was needed in order to match a given pattern.
705        (It was back references and recursion that I had previously got hung up
706        on.) This code has now been added to pcre_study(); it finds a lower bound
707        to the length of subject needed. It is not necessarily the greatest lower
708        bound, but using it to avoid searching strings that are too short does give
709        some useful speed-ups. The value is available to calling programs via
710        pcre_fullinfo().
711    
712    26. While implementing 25, I discovered to my embarrassment that pcretest had
713        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
714        study optimizations had never been tested with that matching function.
715        Oops. What is worse, even when it was passed study data, there was a bug in
716        pcre_dfa_exec() that meant it never actually used it. Double oops. There
717        were also very few tests of studied patterns with pcre_dfa_exec().
718    
719    27. If (?| is used to create subpatterns with duplicate numbers, they are now
720        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
721        on the other side of the coin, they are no longer allowed to have different
722        names, because these cannot be distinguished in PCRE, and this has caused
723        confusion. (This is a difference from Perl.)
724    
725    28. When duplicate subpattern names are present (necessarily with different
726        numbers, as required by 27 above), and a test is made by name in a
727        conditional pattern, either for a subpattern having been matched, or for
728        recursion in such a pattern, all the associated numbered subpatterns are
729        tested, and the overall condition is true if the condition is true for any
730        one of them. This is the way Perl works, and is also more like the way
731        testing by number works.
732    
733    
734    Version 7.9 11-Apr-09
735    ---------------------
736    
737    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
738        (pcretest), all targets were linked against these libraries. This included
739        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
740        libraries. This caused unwanted dependencies to be created. This problem
741        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
742        pcretest is linked with readline.
743    
744    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
745        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
746        moved outside it again, because FALSE and TRUE are already defined in AIX,
747        but BOOL is not.
748    
749    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
750        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
751    
752    4.  The pcregrep documentation said spaces were inserted as well as colons (or
753        hyphens) following file names and line numbers when outputting matching
754        lines. This is not true; no spaces are inserted. I have also clarified the
755        wording for the --colour (or --color) option.
756    
757    5.  In pcregrep, when --colour was used with -o, the list of matching strings
758        was not coloured; this is different to GNU grep, so I have changed it to be
759        the same.
760    
761    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
762        each matching line was coloured. Now it goes on to look for further matches
763        of any of the test patterns, which is the same behaviour as GNU grep.
764    
765    7.  A pattern that could match an empty string could cause pcregrep to loop; it
766        doesn't make sense to accept an empty string match in pcregrep, so I have
767        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
768        seems to be how GNU grep behaves.
769    
770    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
771        start or after a newline", because the conditional assertion was not being
772        correctly handled. The rule now is that both the assertion and what follows
773        in the first alternative must satisfy the test.
774    
775    9.  If auto-callout was enabled in a pattern with a conditional group whose
776        condition was an assertion, PCRE could crash during matching, both with
777        pcre_exec() and pcre_dfa_exec().
778    
779    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
780        used for matching.
781    
782    11. Unicode property support in character classes was not working for
783        characters (bytes) greater than 127 when not in UTF-8 mode.
784    
785    12. Added the -M command line option to pcretest.
786    
787    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
788    
789    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
790    
791    16. Added comments and documentation about mis-use of no_arg in the C++
792        wrapper.
793    
794    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
795        from Martin Jerabek that uses macro names for all relevant character and
796        string constants.
797    
798    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
799        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
800        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
801        these, but not everybody uses configure.
802    
803    19. A conditional group that had only one branch was not being correctly
804        recognized as an item that could match an empty string. This meant that an
805        enclosing group might also not be so recognized, causing infinite looping
806        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
807        with the subject "ab", where knowledge that the repeated group can match
808        nothing is needed in order to break the loop.
809    
810    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
811        exec(), but without supplying a callout function, matching went wrong.
812    
813    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
814        leak if the size of the offset vector was greater than 30. When the vector
815        is smaller, the saved offsets during recursion go onto a local stack
816        vector, but for larger vectors malloc() is used. It was failing to free
817        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
818        error, in fact).
819    
820    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
821        heapframe that is used only when UTF-8 support is enabled. This caused no
822        problem, but was untidy.
823    
824    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
825        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
826        included within another project.
827    
828    24. Steven Van Ingelgem's patches to add more options to the CMake support,
829        slightly modified by me:
830    
831          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
832              not building pcregrep.
833    
834          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
835              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
836    
837    25. Forward references, both numeric and by name, in patterns that made use of
838        duplicate group numbers, could behave incorrectly or give incorrect errors,
839        because when scanning forward to find the reference group, PCRE was not
840        taking into account the duplicate group numbers. A pattern such as
841        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
842    
843    26. Changed a few more instances of "const unsigned char *" to USPTR, making
844        the feature of a custom pointer more persuasive (as requested by a user).
845    
846    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
847        pcretest.c, inside #ifndefs, because it seems they are sometimes already
848        pre-defined.
849    
850    28. Added support for (*UTF8) at the start of a pattern.
851    
852    29. Arrange for flags added by the "release type" setting in CMake to be shown
853        in the configuration summary.
854    
855    
856    Version 7.8 05-Sep-08
857  ---------------------  ---------------------
858    
859  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
# Line 13  Version 8.0 02 Jul-08 Line 865  Version 8.0 02 Jul-08
865    
866  2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more  2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
867      scripts.      scripts.
868    
869  3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained  3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
870      a group with a zero qualifier. The result of the study could be incorrect,      a group with a zero qualifier. The result of the study could be incorrect,
871      or the function might crash, depending on the pattern.      or the function might crash, depending on the pattern.
872    
873  4.  Caseless matching was not working for non-ASCII characters in back  4.  Caseless matching was not working for non-ASCII characters in back
874      references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.      references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
875      It now works when Unicode Property Support is available.      It now works when Unicode Property Support is available.
876    
877    5.  In pcretest, an escape such as \x{de} in the data was always generating
878        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
879        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
880        truncation.
881    
882    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
883    
884    7.  Added two (int) casts to pcregrep when printing the difference of two
885        pointers, in case they are 64-bit values.
886    
887    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
888        test 2 if it fails.
889    
890    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
891        and a #define of that name to empty if it is not externally set. This is to
892        allow users of MSVC to set it if necessary.
893    
894    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
895        the convenience functions in the pcre_get.c source file.
896    
897    11. An option change at the start of a pattern that had top-level alternatives
898        could cause overwriting and/or a crash. This command provoked a crash in
899        some environments:
900    
901          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
902    
903        This potential security problem was recorded as CVE-2008-2371.
904    
905    12. For a pattern where the match had to start at the beginning or immediately
906        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
907        pcre_dfa_exec() could read past the end of the passed subject if there was
908        no match. To help with detecting such bugs (e.g. with valgrind), I modified
909        pcretest so that it places the subject at the end of its malloc-ed buffer.
910    
911    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
912        exec() might read past the end of the data buffer in UTF-8 mode.
913    
914    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
915        the data contained the byte 0x85 as part of a UTF-8 character within its
916        first line. This applied both to normal and DFA matching.
917    
918    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
919        /^[^d]*?$/8 failed to match "abc".
920    
921    16. Added a missing copyright notice to pcrecpp_internal.h.
922    
923    17. Make it more clear in the documentation that values returned from
924        pcre_exec() in ovector are byte offsets, not character counts.
925    
926    18. Tidied a few places to stop certain compilers from issuing warnings.
927    
928    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
929        supplied by Stefan Weber. I made a further small update for 7.8 because
930        there is a change of source arrangements: the pcre_searchfuncs.c module is
931        replaced by pcre_ucd.c.
932    
933    
934  Version 7.7 07-May-08  Version 7.7 07-May-08

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