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

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