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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 09-Aug-07  Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
14    
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
23    
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
28    
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
34    
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
38    
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
46    
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
55    
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
59    
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
62    
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
68    
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
72    
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
77    
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
86    
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
90    
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
95    
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
102    
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
106    
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
109    
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
113    
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
116    
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
125    
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
129    
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
136    
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
140    
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
147    
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
151    
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
154    
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
157    
158    
159    
160    Version 8.12 15-Jan-2011
161    ------------------------
162    
163    1.  Fixed some typos in the markup of the man pages, and wrote a script that
164        checks for such things as part of the documentation building process.
165    
166    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
167        --match-limit and --recursion-limit options (added for 8.11). In
168        particular, this made one of the standard tests fail. (The integer value
169        went into the wrong half of a long int.)
170    
171    3.  If the --colour option was given to pcregrep with -v (invert match), it
172        did strange things, either producing crazy output, or crashing. It should,
173        of course, ignore a request for colour when reporting lines that do not
174        match.
175    
176    4.  Another pcregrep bug caused similar problems if --colour was specified with
177        -M (multiline) and the pattern match finished with a line ending.
178    
179    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
180        matched in multiline mode, the following line was shown as part of the
181        match. This seems wrong, so I have changed it.
182    
183    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
184        the check for further matches in the same line (so they could be coloured)
185        to overrun the end of the current line. If another match was found, it was
186        incorrectly shown (and then shown again when found in the next line).
187    
188    7.  If pcregrep was compiled under Windows, there was a reference to the
189        function pcregrep_exit() before it was defined. I am assuming this was
190        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
191        reported by a user. I've moved the definition above the reference.
192    
193    
194    Version 8.11 10-Dec-2010
195    ------------------------
196    
197    1.  (*THEN) was not working properly if there were untried alternatives prior
198        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
199        backtracked to try for "b" instead of moving to the next alternative branch
200        at the same level (in this case, to look for "c"). The Perl documentation
201        is clear that when (*THEN) is backtracked onto, it goes to the "next
202        alternative in the innermost enclosing group".
203    
204    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
205        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
206        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
207        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
208        (*THEN).
209    
210    3.  If \s appeared in a character class, it removed the VT character from
211        the class, even if it had been included by some previous item, for example
212        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
213        of \s, but is part of the POSIX "space" class.)
214    
215    4.  A partial match never returns an empty string (because you can always
216        match an empty string at the end of the subject); however the checking for
217        an empty string was starting at the "start of match" point. This has been
218        changed to the "earliest inspected character" point, because the returned
219        data for a partial match starts at this character. This means that, for
220        example, /(?<=abc)def/ gives a partial match for the subject "abc"
221        (previously it gave "no match").
222    
223    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
224        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
225        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
226        has an implication that the given string is incomplete (because a partial
227        match is preferred over a full match). For this reason, these items now
228        give a partial match in this situation. [Aside: previously, the one case
229        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
230        match rather than a full match, which was wrong by the old rules, but is
231        now correct.]
232    
233    6.  There was a bug in the handling of #-introduced comments, recognized when
234        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
235        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
236        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
237        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
238        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
239        places in pcre_compile().
240    
241    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
242        comments when looking ahead for named forward references to subpatterns,
243        the only newline sequence it recognized was NL. It now handles newlines
244        according to the set newline convention.
245    
246    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
247        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
248        cater for a lack of strerror(). These oversights have been fixed.
249    
250    9.  Added --match-limit and --recursion-limit to pcregrep.
251    
252    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
253    
254    11. When the -o option was used, pcregrep was setting a return code of 1, even
255        when matches were found, and --line-buffered was not being honoured.
256    
257    12. Added an optional parentheses number to the -o and --only-matching options
258        of pcregrep.
259    
260    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
261        can match an empty string. The code to do it in pcretest and pcredemo
262        needed fixing:
263    
264        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
265            only one byte after an empty string match just before CRLF (this case
266            just got forgotten; "any" and "anycrlf" were OK).
267    
268        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
269            mode when an empty string match preceded an ASCII character followed by
270            a non-ASCII character. (The code for advancing by one character rather
271            than one byte was nonsense.)
272    
273        (c) The pcredemo.c sample program did not have any code at all to handle
274            the cases when CRLF is a valid newline sequence.
275    
276    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
277        as a starting offset was within the subject string. There is now a new
278        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
279        negative or greater than the length of the string. In order to test this,
280        pcretest is extended to allow the setting of negative starting offsets.
281    
282    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
283        starting offset points to the beginning of a UTF-8 character was
284        unnecessarily clumsy. I tidied it up.
285    
286    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
287        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
288    
289    17. Nobody had reported that the --include_dir option, which was added in
290        release 7.7 should have been called --include-dir (hyphen, not underscore)
291        for compatibility with GNU grep. I have changed it to --include-dir, but
292        left --include_dir as an undocumented synonym, and the same for
293        --exclude-dir, though that is not available in GNU grep, at least as of
294        release 2.5.4.
295    
296    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
297        characters from a string of bytes) have been redefined so as not to use
298        loops, in order to improve performance in some environments. At the same
299        time, I abstracted some of the common code into auxiliary macros to save
300        repetition (this should not affect the compiled code).
301    
302    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
303        compile-time error is now given if \c is not followed by an ASCII
304        character, that is, a byte less than 128. (In EBCDIC mode, the code is
305        different, and any byte value is allowed.)
306    
307    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
308        START_OPTIMIZE option, which is now allowed at compile time - but just
309        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
310        to pcregrep and other applications that have no direct access to PCRE
311        options. The new /Y option in pcretest sets this option when calling
312        pcre_compile().
313    
314    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
315        back references. Groups containing recursive back references were forced to
316        be atomic by that change, but in the case of named groups, the amount of
317        memory required was incorrectly computed, leading to "Failed: internal
318        error: code overflow". This has been fixed.
319    
320    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
321        pcretest.c, to avoid build problems in some Borland environments.
322    
323    
324    Version 8.10 25-Jun-2010
325    ------------------------
326    
327    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
328        THEN.
329    
330    2.  (*ACCEPT) was not working when inside an atomic group.
331    
332    3.  Inside a character class, \B is treated as a literal by default, but
333        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
334        causes the error). The code is unchanged, but I tidied the documentation.
335    
336    4.  Inside a character class, PCRE always treated \R and \X as literals,
337        whereas Perl faults them if its -w option is set. I have changed PCRE so
338        that it faults them when PCRE_EXTRA is set.
339    
340    5.  Added support for \N, which always matches any character other than
341        newline. (It is the same as "." when PCRE_DOTALL is not set.)
342    
343    6.  When compiling pcregrep with newer versions of gcc which may have
344        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
345        declared with attribute warn_unused_result" were given. Just casting the
346        result to (void) does not stop the warnings; a more elaborate fudge is
347        needed. I've used a macro to implement this.
348    
349    7.  Minor change to pcretest.c to avoid a compiler warning.
350    
351    8.  Added four artifical Unicode properties to help with an option to make
352        \s etc use properties (see next item). The new properties are: Xan
353        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
354    
355    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
356        use Unicode properties. (*UCP) at the start of a pattern can be used to set
357        this option. Modified pcretest to add /W to test this facility. Added
358        REG_UCP to make it available via the POSIX interface.
359    
360    10. Added --line-buffered to pcregrep.
361    
362    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
363        studied, and the match started with a letter with a code point greater than
364        127 whose first byte was different to the first byte of the other case of
365        the letter, the other case of this starting letter was not recognized
366        (#976).
367    
368    12. If a pattern that was studied started with a repeated Unicode property
369        test, for example, \p{Nd}+, there was the theoretical possibility of
370        setting up an incorrect bitmap of starting bytes, but fortunately it could
371        not have actually happened in practice until change 8 above was made (it
372        added property types that matched character-matching opcodes).
373    
374    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
375        possible starting bytes for non-anchored patterns.
376    
377    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
378        \R, and also a number of cases that involve Unicode properties, both
379        explicit and implicit when PCRE_UCP is set.
380    
381    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
382        input, it could crash or give wrong results if characters with values
383        greater than 0xc0 were present in the subject string. (Detail: it assumed
384        UTF-8 input when processing these items.)
385    
386    16. Added a lot of (int) casts to avoid compiler warnings in systems where
387        size_t is 64-bit (#991).
388    
389    17. Added a check for running out of memory when PCRE is compiled with
390        --disable-stack-for-recursion (#990).
391    
392    18. If the last data line in a file for pcretest does not have a newline on
393        the end, a newline was missing in the output.
394    
395    19. The default pcre_chartables.c file recognizes only ASCII characters (values
396        less than 128) in its various bitmaps. However, there is a facility for
397        generating tables according to the current locale when PCRE is compiled. It
398        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
399        characters, are recognized by isspace() and therefore were getting set in
400        these tables, and indeed these tables seem to approximate to ISO 8859. This
401        caused a problem in UTF-8 mode when pcre_study() was used to create a list
402        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
403        which of course cannot start UTF-8 characters. I have changed the code so
404        that only real ASCII characters (less than 128) and the correct starting
405        bytes for UTF-8 encodings are set for characters greater than 127 when in
406        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
407        altogether.)
408    
409    20. Added the /T option to pcretest so as to be able to run tests with non-
410        standard character tables, thus making it possible to include the tests
411        used for 19 above in the standard set of tests.
412    
413    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
414        reference to a subpattern the other side of a comment that contains an
415        opening parenthesis caused either an internal compiling error, or a
416        reference to the wrong subpattern.
417    
418    
419    Version 8.02 19-Mar-2010
420    ------------------------
421    
422    1.  The Unicode data tables have been updated to Unicode 5.2.0.
423    
424    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
425        configured.
426    
427    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
428        original author of that file, following a query about its status.
429    
430    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
431        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
432    
433    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
434        quantifier applied to a forward-referencing subroutine call, could compile
435        incorrect code or give the error "internal error: previously-checked
436        referenced subpattern not found".
437    
438    6.  Both MS Visual Studio and Symbian OS have problems with initializing
439        variables to point to external functions. For these systems, therefore,
440        pcre_malloc etc. are now initialized to local functions that call the
441        relevant global functions.
442    
443    7.  There were two entries missing in the vectors called coptable and poptable
444        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
445        I've fixed the data, and added a kludgy way of testing at compile time that
446        the lengths are correct (equal to the number of opcodes).
447    
448    8.  Following on from 7, I added a similar kludge to check the length of the
449        eint vector in pcreposix.c.
450    
451    9.  Error texts for pcre_compile() are held as one long string to avoid too
452        much relocation at load time. To find a text, the string is searched,
453        counting zeros. There was no check for running off the end of the string,
454        which could happen if a new error number was added without updating the
455        string.
456    
457    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
458    
459    11. \K was not working if it appeared in an atomic group or in a group that
460        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
461        \K is "not well defined" if used in an assertion. PCRE now accepts it if
462        the assertion is positive, but not if it is negative.
463    
464    12. Change 11 fortuitously reduced the size of the stack frame used in the
465        "match()" function of pcre_exec.c by one pointer. Forthcoming
466        implementation of support for (*MARK) will need an extra pointer on the
467        stack; I have reserved it now, so that the stack frame size does not
468        decrease.
469    
470    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
471        item in branch that calls a recursion is a subroutine call - as in the
472        second branch in the above example - was incorrectly given the compile-
473        time error "recursive call could loop indefinitely" because pcre_compile()
474        was not correctly checking the subroutine for matching a non-empty string.
475    
476    14. The checks for overrunning compiling workspace could trigger after an
477        overrun had occurred. This is a "should never occur" error, but it can be
478        triggered by pathological patterns such as hundreds of nested parentheses.
479        The checks now trigger 100 bytes before the end of the workspace.
480    
481    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
482    
483    
484    Version 8.01 19-Jan-2010
485    ------------------------
486    
487    1.  If a pattern contained a conditional subpattern with only one branch (in
488        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
489        computed the wrong minimum data length (which is of course zero for such
490        subpatterns). This could cause incorrect "no match" results.
491    
492    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
493        the pattern is reset in the first branch, pcre_compile() failed with
494        "internal error: code overflow at offset...". This happened only when
495        the reset was to the original external option setting. (An optimization
496        abstracts leading options settings into an external setting, which was the
497        cause of this.)
498    
499    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
500        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
501        assertion pattern did not match (meaning that the assertion was true), it
502        was incorrectly treated as false if the SKIP had been reached during the
503        matching. This also applied to assertions used as conditions.
504    
505    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
506        assertion subpattern, including such a pattern used as a condition,
507        unpredictable results occurred, instead of the error return
508        PCRE_ERROR_DFA_UITEM.
509    
510    5.  The C++ GlobalReplace function was not working like Perl for the special
511        situation when an empty string is matched. It now does the fancy magic
512        stuff that is necessary.
513    
514    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
515        removed. (These were left over from very, very early versions of PCRE.)
516    
517    7.  Some cosmetic changes to the code to make life easier when compiling it
518        as part of something else:
519    
520        (a) Change DEBUG to PCRE_DEBUG.
521    
522        (b) In pcre_compile(), rename the member of the "branch_chain" structure
523            called "current" as "current_branch", to prevent a collision with the
524            Linux macro when compiled as a kernel module.
525    
526        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
527            prevent a collision with the Linux macro when compiled as a kernel
528            module.
529    
530    8.  In pcre_compile() there are some checks for integer overflows that used to
531        cast potentially large values to (double). This has been changed to that
532        when building, a check for int64_t is made, and if it is found, it is used
533        instead, thus avoiding the use of floating point arithmetic. (There is no
534        other use of FP in PCRE.) If int64_t is not found, the fallback is to
535        double.
536    
537    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
538        2005 (difference between two addresses compared to an unsigned value).
539    
540    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
541        custom one, because of the following reported problem in Windows:
542    
543          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
544              under Win32.
545          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
546              therefore missing the function definition.
547          - The compiler thus generates a "C" signature for the test function.
548          - The linker fails to find the "C" function.
549          - PCRE fails to configure if asked to do so against libbz2.
550    
551    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
552        messages were output:
553    
554          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
555          rerunning libtoolize, to keep the correct libtool macros in-tree.
556          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
557    
558        I have done both of these things.
559    
560    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
561        most of the time, it *can* run out if it is given a pattern that contains a
562        runaway infinite recursion. I updated the discussion in the pcrestack man
563        page.
564    
565    13. Now that we have gone to the x.xx style of version numbers, the minor
566        version may start with zero. Using 08 or 09 is a bad idea because users
567        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
568        interpreted as invalid octal numbers. I've updated the previous comment in
569        configure.ac, and also added a check that gives an error if 08 or 09 are
570        used.
571    
572    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
573        causing partial matching to fail when the end of the subject matched \W
574        in a UTF-8 pattern where \W was quantified with a minimum of 3.
575    
576    15. There were some discrepancies between the declarations in pcre_internal.h
577        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
578        their definitions. The declarations used "const uschar *" and the
579        definitions used USPTR. Even though USPTR is normally defined as "const
580        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
581        reported that: "This difference in casting confuses some C++ compilers, for
582        example, SunCC recognizes above declarations as different functions and
583        generates broken code for hbpcre." I have changed the declarations to use
584        USPTR.
585    
586    16. GNU libtool is named differently on some systems. The autogen.sh script now
587        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
588        (FreeBSD).
589    
590    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
591        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
592        comment: "Figure out how to create a longlong from a string: strtoll and
593        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
594        instance, but it only takes 2 args instead of 3!"
595    
596    18. A subtle bug concerned with back references has been fixed by a change of
597        specification, with a corresponding code fix. A pattern such as
598        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
599        refers, was giving matches when it shouldn't. For example, xa=xaaa would
600        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
601        same bug. Such groups have to be quantified to be useful, or contained
602        inside another quantified group. (If there's no repetition, the reference
603        can never match.) The problem arises because, having left the group and
604        moved on to the rest of the pattern, a later failure that backtracks into
605        the group uses the captured value from the final iteration of the group
606        rather than the correct earlier one. I have fixed this in PCRE by forcing
607        any group that contains a reference to itself to be an atomic group; that
608        is, there cannot be any backtracking into it once it has completed. This is
609        similar to recursive and subroutine calls.
610    
611    
612    Version 8.00 19-Oct-09
613    ----------------------
614    
615    1.  The table for translating pcre_compile() error codes into POSIX error codes
616        was out-of-date, and there was no check on the pcre_compile() error code
617        being within the table. This could lead to an OK return being given in
618        error.
619    
620    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
621        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
622        in a Windows environment.
623    
624    3.  The pcregrep --count option prints the count for each file even when it is
625        zero, as does GNU grep. However, pcregrep was also printing all files when
626        --files-with-matches was added. Now, when both options are given, it prints
627        counts only for those files that have at least one match. (GNU grep just
628        prints the file name in this circumstance, but including the count seems
629        more useful - otherwise, why use --count?) Also ensured that the
630        combination -clh just lists non-zero counts, with no names.
631    
632    4.  The long form of the pcregrep -F option was incorrectly implemented as
633        --fixed_strings instead of --fixed-strings. This is an incompatible change,
634        but it seems right to fix it, and I didn't think it was worth preserving
635        the old behaviour.
636    
637    5.  The command line items --regex=pattern and --regexp=pattern were not
638        recognized by pcregrep, which required --regex pattern or --regexp pattern
639        (with a space rather than an '='). The man page documented the '=' forms,
640        which are compatible with GNU grep; these now work.
641    
642    6.  No libpcreposix.pc file was created for pkg-config; there was just
643        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
644    
645    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
646        when UCP support is not needed, by modifying the Python script that
647        generates it from Unicode data files. This should not matter if the module
648        is correctly used as a library, but I received one complaint about 50K of
649        unwanted data. My guess is that the person linked everything into his
650        program rather than using a library. Anyway, it does no harm.
651    
652    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
653        was a minimum greater than 1 for a wide character in a possessive
654        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
655        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
656        character. Chaos in the form of incorrect output or a compiling loop could
657        result.
658    
659    9.  The restrictions on what a pattern can contain when partial matching is
660        requested for pcre_exec() have been removed. All patterns can now be
661        partially matched by this function. In addition, if there are at least two
662        slots in the offset vector, the offset of the earliest inspected character
663        for the match and the offset of the end of the subject are set in them when
664        PCRE_ERROR_PARTIAL is returned.
665    
666    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
667        synonymous with PCRE_PARTIAL, for backwards compatibility, and
668        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
669        and may be more useful for multi-segment matching.
670    
671    11. Partial matching with pcre_exec() is now more intuitive. A partial match
672        used to be given if ever the end of the subject was reached; now it is
673        given only if matching could not proceed because another character was
674        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
675        string "Z", which now yields "no match" instead of "partial match". In the
676        case of pcre_dfa_exec(), "no match" is given if every matching path for the
677        final character ended with (*FAIL).
678    
679    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
680        if the pattern had a "must contain" character that was already found in the
681        earlier partial match, unless partial matching was again requested. For
682        example, with the pattern /dog.(body)?/, the "must contain" character is
683        "g". If the first part-match was for the string "dog", restarting with
684        "sbody" failed. This bug has been fixed.
685    
686    13. The string returned by pcre_dfa_exec() after a partial match has been
687        changed so that it starts at the first inspected character rather than the
688        first character of the match. This makes a difference only if the pattern
689        starts with a lookbehind assertion or \b or \B (\K is not supported by
690        pcre_dfa_exec()). It's an incompatible change, but it makes the two
691        matching functions compatible, and I think it's the right thing to do.
692    
693    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
694        so that the demonstration program is easily available in environments where
695        PCRE has not been installed from source.
696    
697    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
698        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
699        library.
700    
701    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
702        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
703        is not the first non-POSIX option to be added. Clearly some people find
704        these options useful.
705    
706    17. If a caller to the POSIX matching function regexec() passes a non-zero
707        value for nmatch with a NULL value for pmatch, the value of
708        nmatch is forced to zero.
709    
710    18. RunGrepTest did not have a test for the availability of the -u option of
711        the diff command, as RunTest does. It now checks in the same way as
712        RunTest, and also checks for the -b option.
713    
714    19. If an odd number of negated classes containing just a single character
715        interposed, within parentheses, between a forward reference to a named
716        subpattern and the definition of the subpattern, compilation crashed with
717        an internal error, complaining that it could not find the referenced
718        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
719        [The bug was that it was starting one character too far in when skipping
720        over the character class, thus treating the ] as data rather than
721        terminating the class. This meant it could skip too much.]
722    
723    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
724        /g option in pcretest when the pattern contains \K, which makes it possible
725        to have an empty string match not at the start, even when the pattern is
726        anchored. Updated pcretest and pcredemo to use this option.
727    
728    21. If the maximum number of capturing subpatterns in a recursion was greater
729        than the maximum at the outer level, the higher number was returned, but
730        with unset values at the outer level. The correct (outer level) value is
731        now given.
732    
733    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
734        PCRE did not set those parentheses (unlike Perl). I have now found a way to
735        make it do so. The string so far is captured, making this feature
736        compatible with Perl.
737    
738    23. The tests have been re-organized, adding tests 11 and 12, to make it
739        possible to check the Perl 5.10 features against Perl 5.10.
740    
741    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
742        pattern matches a fixed length string. PCRE did not allow this; now it
743        does. Neither allows recursion.
744    
745    25. I finally figured out how to implement a request to provide the minimum
746        length of subject string that was needed in order to match a given pattern.
747        (It was back references and recursion that I had previously got hung up
748        on.) This code has now been added to pcre_study(); it finds a lower bound
749        to the length of subject needed. It is not necessarily the greatest lower
750        bound, but using it to avoid searching strings that are too short does give
751        some useful speed-ups. The value is available to calling programs via
752        pcre_fullinfo().
753    
754    26. While implementing 25, I discovered to my embarrassment that pcretest had
755        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
756        study optimizations had never been tested with that matching function.
757        Oops. What is worse, even when it was passed study data, there was a bug in
758        pcre_dfa_exec() that meant it never actually used it. Double oops. There
759        were also very few tests of studied patterns with pcre_dfa_exec().
760    
761    27. If (?| is used to create subpatterns with duplicate numbers, they are now
762        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
763        on the other side of the coin, they are no longer allowed to have different
764        names, because these cannot be distinguished in PCRE, and this has caused
765        confusion. (This is a difference from Perl.)
766    
767    28. When duplicate subpattern names are present (necessarily with different
768        numbers, as required by 27 above), and a test is made by name in a
769        conditional pattern, either for a subpattern having been matched, or for
770        recursion in such a pattern, all the associated numbered subpatterns are
771        tested, and the overall condition is true if the condition is true for any
772        one of them. This is the way Perl works, and is also more like the way
773        testing by number works.
774    
775    
776    Version 7.9 11-Apr-09
777    ---------------------
778    
779    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
780        (pcretest), all targets were linked against these libraries. This included
781        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
782        libraries. This caused unwanted dependencies to be created. This problem
783        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
784        pcretest is linked with readline.
785    
786    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
787        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
788        moved outside it again, because FALSE and TRUE are already defined in AIX,
789        but BOOL is not.
790    
791    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
792        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
793    
794    4.  The pcregrep documentation said spaces were inserted as well as colons (or
795        hyphens) following file names and line numbers when outputting matching
796        lines. This is not true; no spaces are inserted. I have also clarified the
797        wording for the --colour (or --color) option.
798    
799    5.  In pcregrep, when --colour was used with -o, the list of matching strings
800        was not coloured; this is different to GNU grep, so I have changed it to be
801        the same.
802    
803    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
804        each matching line was coloured. Now it goes on to look for further matches
805        of any of the test patterns, which is the same behaviour as GNU grep.
806    
807    7.  A pattern that could match an empty string could cause pcregrep to loop; it
808        doesn't make sense to accept an empty string match in pcregrep, so I have
809        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
810        seems to be how GNU grep behaves.
811    
812    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
813        start or after a newline", because the conditional assertion was not being
814        correctly handled. The rule now is that both the assertion and what follows
815        in the first alternative must satisfy the test.
816    
817    9.  If auto-callout was enabled in a pattern with a conditional group whose
818        condition was an assertion, PCRE could crash during matching, both with
819        pcre_exec() and pcre_dfa_exec().
820    
821    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
822        used for matching.
823    
824    11. Unicode property support in character classes was not working for
825        characters (bytes) greater than 127 when not in UTF-8 mode.
826    
827    12. Added the -M command line option to pcretest.
828    
829    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
830    
831    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
832    
833    16. Added comments and documentation about mis-use of no_arg in the C++
834        wrapper.
835    
836    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
837        from Martin Jerabek that uses macro names for all relevant character and
838        string constants.
839    
840    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
841        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
842        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
843        these, but not everybody uses configure.
844    
845    19. A conditional group that had only one branch was not being correctly
846        recognized as an item that could match an empty string. This meant that an
847        enclosing group might also not be so recognized, causing infinite looping
848        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
849        with the subject "ab", where knowledge that the repeated group can match
850        nothing is needed in order to break the loop.
851    
852    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
853        exec(), but without supplying a callout function, matching went wrong.
854    
855    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
856        leak if the size of the offset vector was greater than 30. When the vector
857        is smaller, the saved offsets during recursion go onto a local stack
858        vector, but for larger vectors malloc() is used. It was failing to free
859        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
860        error, in fact).
861    
862    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
863        heapframe that is used only when UTF-8 support is enabled. This caused no
864        problem, but was untidy.
865    
866    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
867        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
868        included within another project.
869    
870    24. Steven Van Ingelgem's patches to add more options to the CMake support,
871        slightly modified by me:
872    
873          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
874              not building pcregrep.
875    
876          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
877              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
878    
879    25. Forward references, both numeric and by name, in patterns that made use of
880        duplicate group numbers, could behave incorrectly or give incorrect errors,
881        because when scanning forward to find the reference group, PCRE was not
882        taking into account the duplicate group numbers. A pattern such as
883        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
884    
885    26. Changed a few more instances of "const unsigned char *" to USPTR, making
886        the feature of a custom pointer more persuasive (as requested by a user).
887    
888    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
889        pcretest.c, inside #ifndefs, because it seems they are sometimes already
890        pre-defined.
891    
892    28. Added support for (*UTF8) at the start of a pattern.
893    
894    29. Arrange for flags added by the "release type" setting in CMake to be shown
895        in the configuration summary.
896    
897    
898    Version 7.8 05-Sep-08
899    ---------------------
900    
901    1.  Replaced UCP searching code with optimized version as implemented for Ad
902        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
903        stage table and inline lookup instead of a function, giving speed ups of 2
904        to 5 times on some simple patterns that I tested. Permission was given to
905        distribute the MultiStage2.py script that generates the tables (it's not in
906        the tarball, but is in the Subversion repository).
907    
908    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
909        scripts.
910    
911    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
912        a group with a zero qualifier. The result of the study could be incorrect,
913        or the function might crash, depending on the pattern.
914    
915    4.  Caseless matching was not working for non-ASCII characters in back
916        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
917        It now works when Unicode Property Support is available.
918    
919    5.  In pcretest, an escape such as \x{de} in the data was always generating
920        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
921        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
922        truncation.
923    
924    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
925    
926    7.  Added two (int) casts to pcregrep when printing the difference of two
927        pointers, in case they are 64-bit values.
928    
929    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
930        test 2 if it fails.
931    
932    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
933        and a #define of that name to empty if it is not externally set. This is to
934        allow users of MSVC to set it if necessary.
935    
936    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
937        the convenience functions in the pcre_get.c source file.
938    
939    11. An option change at the start of a pattern that had top-level alternatives
940        could cause overwriting and/or a crash. This command provoked a crash in
941        some environments:
942    
943          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
944    
945        This potential security problem was recorded as CVE-2008-2371.
946    
947    12. For a pattern where the match had to start at the beginning or immediately
948        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
949        pcre_dfa_exec() could read past the end of the passed subject if there was
950        no match. To help with detecting such bugs (e.g. with valgrind), I modified
951        pcretest so that it places the subject at the end of its malloc-ed buffer.
952    
953    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
954        exec() might read past the end of the data buffer in UTF-8 mode.
955    
956    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
957        the data contained the byte 0x85 as part of a UTF-8 character within its
958        first line. This applied both to normal and DFA matching.
959    
960    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
961        /^[^d]*?$/8 failed to match "abc".
962    
963    16. Added a missing copyright notice to pcrecpp_internal.h.
964    
965    17. Make it more clear in the documentation that values returned from
966        pcre_exec() in ovector are byte offsets, not character counts.
967    
968    18. Tidied a few places to stop certain compilers from issuing warnings.
969    
970    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
971        supplied by Stefan Weber. I made a further small update for 7.8 because
972        there is a change of source arrangements: the pcre_searchfuncs.c module is
973        replaced by pcre_ucd.c.
974    
975    
976    Version 7.7 07-May-08
977    ---------------------
978    
979    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
980        a string to a long long, pretend we don't even have a long long." This is
981        done by checking for the strtoq, strtoll, and _strtoi64 functions.
982    
983    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
984        pre-7.6 versions, which defined a global no_arg variable instead of putting
985        it in the RE class. (See also #8 below.)
986    
987    3.  Remove a line of dead code, identified by coverity and reported by Nuno
988        Lopes.
989    
990    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
991    
992        (1) The include/exclude patterns were being applied to the whole pathnames
993            of files, instead of just to the final components.
994    
995        (2) If there was more than one level of directory, the subdirectories were
996            skipped unless they satisfied the include/exclude conditions. This is
997            inconsistent with GNU grep (and could even be seen as contrary to the
998            pcregrep specification - which I improved to make it absolutely clear).
999            The action now is always to scan all levels of directory, and just
1000            apply the include/exclude patterns to regular files.
1001    
1002    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1003        --exclude_dir in the tests to avoid scanning .svn directories.
1004    
1005    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1006        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1007        doesn't support NULs in patterns.
1008    
1009    7.  Added some missing "const"s to declarations of static tables in
1010        pcre_compile.c and pcre_dfa_exec.c.
1011    
1012    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1013        caused by fix #2  above. (Subsequently also a second patch to fix the
1014        first patch. And a third patch - this was a messy problem.)
1015    
1016    9.  Applied Craig's patch to remove the use of push_back().
1017    
1018    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1019        matching function regexec().
1020    
1021    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1022        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1023        references. PCRE supports relative numbers with this syntax (I don't think
1024        Oniguruma does).
1025    
1026    12. Previously, a group with a zero repeat such as (...){0} was completely
1027        omitted from the compiled regex. However, this means that if the group
1028        was called as a subroutine from elsewhere in the pattern, things went wrong
1029        (an internal error was given). Such groups are now left in the compiled
1030        pattern, with a new opcode that causes them to be skipped at execution
1031        time.
1032    
1033    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1034        to the way PCRE behaves:
1035    
1036        (a) A lone ] character is dis-allowed (Perl treats it as data).
1037    
1038        (b) A back reference to an unmatched subpattern matches an empty string
1039            (Perl fails the current match path).
1040    
1041        (c) A data ] in a character class must be notated as \] because if the
1042            first data character in a class is ], it defines an empty class. (In
1043            Perl it is not possible to have an empty class.) The empty class []
1044            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1045            The negative empty class [^] matches any one character, independently
1046            of the DOTALL setting.
1047    
1048    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1049        non-existent subpattern following a character class starting with ']' and
1050        containing () gave an internal compiling error instead of "reference to
1051        non-existent subpattern". Fortunately, when the pattern did exist, the
1052        compiled code was correct. (When scanning forwards to check for the
1053        existencd of the subpattern, it was treating the data ']' as terminating
1054        the class, so got the count wrong. When actually compiling, the reference
1055        was subsequently set up correctly.)
1056    
1057    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1058        it was being rejected as not supported by pcre_dfa_exec(), even though
1059        other assertions are supported. I have made pcre_dfa_exec() support
1060        (*FAIL).
1061    
1062    16. The implementation of 13c above involved the invention of a new opcode,
1063        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1064        cannot be changed at match time, I realized I could make a small
1065        improvement to matching performance by compiling OP_ALLANY instead of
1066        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1067        on the OP_ANY path.
1068    
1069    17. Compiling pcretest on Windows with readline support failed without the
1070        following two fixes: (1) Make the unistd.h include conditional on
1071        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1072    
1073    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1074        ncurses library to be included for pcretest when ReadLine support is
1075        requested, but also to allow for it to be overridden. This patch came from
1076        Daniel Bergström.
1077    
1078    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1079        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1080        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1081        spotting this.
1082    
1083    
1084    Version 7.6 28-Jan-08
1085    ---------------------
1086    
1087    1.  A character class containing a very large number of characters with
1088        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1089        overflow.
1090    
1091    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1092        HAVE_LONG_LONG is not defined.
1093    
1094    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1095        bring them up to date and include new features. This patch includes:
1096    
1097        - Fixed PH's badly added libz and libbz2 support.
1098        - Fixed a problem with static linking.
1099        - Added pcredemo. [But later removed - see 7 below.]
1100        - Fixed dftables problem and added an option.
1101        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1102            HAVE_LONG_LONG.
1103        - Added readline support for pcretest.
1104        - Added an listing of the option settings after cmake has run.
1105    
1106    4.  A user submitted a patch to Makefile that makes it easy to create
1107        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1108        Makefile.am that cause it to include this special target, without
1109        affecting anything else. Note that the same mingw target plus all
1110        the other distribution libraries and programs are now supported
1111        when configuring with CMake (see 6 below) instead of with
1112        Configure/Make.
1113    
1114    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1115        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1116        exported in the Windows port". It has not yet been confirmed that the patch
1117        solves the problem, but it does no harm.
1118    
1119    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1120        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1121        with CMake, and also correct the comment about stack recursion.
1122    
1123    7.  Remove the automatic building of pcredemo from the ./configure system and
1124        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1125        of a program that users should build themselves after PCRE is installed, so
1126        building it automatically is not really right. What is more, it gave
1127        trouble in some build environments.
1128    
1129    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1130    
1131    
1132    Version 7.5 10-Jan-08
1133    ---------------------
1134    
1135    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1136        values in parens when parsing an RE using the C++ wrapper."
1137    
1138    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1139        Characters greater than 255 were excluded from the class instead of being
1140        included.
1141    
1142    3.  The same bug as (2) above applied to negated POSIX classes such as
1143        [:^space:].
1144    
1145    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1146        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1147        I have changed it.
1148    
1149    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1150        first named subpattern) and a construct such as (?&a) would reference the
1151        first named subpattern whose name started with "a" (in other words, the
1152        length check was missing). Both these problems are fixed. "Subpattern name
1153        expected" is now given for (?&) (a zero-length name), and this patch also
1154        makes it give the same error for \k'' (previously it complained that that
1155        was a reference to a non-existent subpattern).
1156    
1157    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1158        this is right because (?- can be followed by option settings as well as by
1159        digits. I have, however, made the messages clearer.
1160    
1161    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1162        than the number used in the conditional) now cause a compile-time error.
1163        This is actually not compatible with Perl, which accepts such patterns, but
1164        treats the conditional as always being FALSE (as PCRE used to), but it
1165        seems to me that giving a diagnostic is better.
1166    
1167    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1168        and messages.
1169    
1170    9.  Fix two occurrences of "backslash" in comments that should have been
1171        "backspace".
1172    
1173    10. Remove two redundant lines of code that can never be obeyed (their function
1174        was moved elsewhere).
1175    
1176    11. The program that makes PCRE's Unicode character property table had a bug
1177        which caused it to generate incorrect table entries for sequences of
1178        characters that have the same character type, but are in different scripts.
1179        It amalgamated them into a single range, with the script of the first of
1180        them. In other words, some characters were in the wrong script. There were
1181        thirteen such cases, affecting characters in the following ranges:
1182    
1183          U+002b0 - U+002c1
1184          U+0060c - U+0060d
1185          U+0061e - U+00612
1186          U+0064b - U+0065e
1187          U+0074d - U+0076d
1188          U+01800 - U+01805
1189          U+01d00 - U+01d77
1190          U+01d9b - U+01dbf
1191          U+0200b - U+0200f
1192          U+030fc - U+030fe
1193          U+03260 - U+0327f
1194          U+0fb46 - U+0fbb1
1195          U+10450 - U+1049d
1196    
1197    12. The -o option (show only the matching part of a line) for pcregrep was not
1198        compatible with GNU grep in that, if there was more than one match in a
1199        line, it showed only the first of them. It now behaves in the same way as
1200        GNU grep.
1201    
1202    13. If the -o and -v options were combined for pcregrep, it printed a blank
1203        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1204        does the same. The return code can be used to tell if there were any
1205        non-matching lines.
1206    
1207    14. Added --file-offsets and --line-offsets to pcregrep.
1208    
1209    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1210        infinitely looping recursion. The bug was that positive lookaheads were not
1211        being skipped when checking for a possible empty match (negative lookaheads
1212        and both kinds of lookbehind were skipped).
1213    
1214    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1215        inclusion of <windows.h> to before rather than after the definition of
1216        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1217    
1218    17. Specifying a possessive quantifier with a specific limit for a Unicode
1219        character property caused pcre_compile() to compile bad code, which led at
1220        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1221        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1222        caused the error; without that there was no problem.
1223    
1224    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1225    
1226    19. Added --enable-pcretest-libreadline.
1227    
1228    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1229        RE::GlobalReplace(). As a result, the number of replacements returned was
1230        double what it should be. I removed one of the increments, but Craig sent a
1231        later patch that removed the other one (the right fix) and added unit tests
1232        that check the return values (which was not done before).
1233    
1234    21. Several CMake things:
1235    
1236        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1237            the names libpcre and libpcreposix, not just pcre and pcreposix.
1238    
1239        (2) The above change means that pcretest and pcregrep are now correctly
1240            linked with the newly-built libraries, not previously installed ones.
1241    
1242        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1243    
1244    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1245        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1246        UTF-8 newline character). The key issue is that the pattern starts .*;
1247        this means that the match must be either at the beginning, or after a
1248        newline. The bug was in the code for advancing after a failed match and
1249        checking that the new position followed a newline. It was not taking
1250        account of UTF-8 characters correctly.
1251    
1252    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1253        character classes. PCRE was not treating the sequence [:...:] as a
1254        character class unless the ... were all letters. Perl, however, seems to
1255        allow any characters between [: and :], though of course it rejects as
1256        unknown any "names" that contain non-letters, because all the known class
1257        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1258        for example, whereas PCRE did not - it did not recognize a POSIX character
1259        class. This seemed a bit dangerous, so the code has been changed to be
1260        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1261        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1262        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1263        Perl does, and where it didn't before.
1264    
1265    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1266        Windows environments %n is disabled by default.
1267    
1268    
1269    Version 7.4 21-Sep-07
1270    ---------------------
1271    
1272    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1273        means that a class such as [\s] counted as "explicit reference to CR or
1274        LF". That isn't really right - the whole point of the change was to try to
1275        help when there was an actual mention of one of the two characters. So now
1276        the change happens only if \r or \n (or a literal CR or LF) character is
1277        encountered.
1278    
1279    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1280        of both had grown to the point where there were only 3 bits left.
1281        Fortunately, there was spare space in the data structure, and so I have
1282        moved the internal flags into a new 16-bit field to free up more option
1283        bits.
1284    
1285    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1286        but did not set the internal JCHANGED flag - either of these is enough to
1287        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1288        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1289        start sets both bits.
1290    
1291    4.  Added options (at build time, compile time, exec time) to change \R from
1292        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1293    
1294    5.  doc/pcresyntax.html was missing from the distribution.
1295    
1296    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1297        compatibility, even though it is no longer used.
1298    
1299    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1300        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1301        windows.h file is present (where different names are used). [This was
1302        reversed later after testing - see 16 below.]
1303    
1304    8.  Changed all #include <config.h> to #include "config.h". There were also
1305        some further <pcre.h> cases that I changed to "pcre.h".
1306    
1307    9.  When pcregrep was used with the --colour option, it missed the line ending
1308        sequence off the lines that it output.
1309    
1310    10. It was pointed out to me that arrays of string pointers cause lots of
1311        relocations when a shared library is dynamically loaded. A technique of
1312        using a single long string with a table of offsets can drastically reduce
1313        these. I have refactored PCRE in four places to do this. The result is
1314        dramatic:
1315    
1316          Originally:                          290
1317          After changing UCP table:            187
1318          After changing error message table:   43
1319          After changing table of "verbs"       36
1320          After changing table of Posix names   22
1321    
1322        Thanks to the folks working on Gregex for glib for this insight.
1323    
1324    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1325        unicode-properties was also set.
1326    
1327    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1328    
1329    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1330        checked only for CRLF.
1331    
1332    14. Added casts to pcretest.c to avoid compiler warnings.
1333    
1334    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1335    
1336    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1337        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1338        entirely. This removes changes made in 7 above.
1339    
1340    17. The CMake files have been updated, and there is now more information about
1341        building with CMake in the NON-UNIX-USE document.
1342    
1343    
1344    Version 7.3 28-Aug-07
1345  ---------------------  ---------------------
1346    
1347   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 98  Version 7.3 09-Aug-07 Line 1438  Version 7.3 09-Aug-07
1438      the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the      the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1439      full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still      full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1440      does: it's just the validity check that is more restrictive.      does: it's just the validity check that is more restrictive.
1441    
1442  16. Inserted checks for integer overflows during escape sequence (backslash)  16. Inserted checks for integer overflows during escape sequence (backslash)
1443      processing, and also fixed erroneous offset values for syntax errors during      processing, and also fixed erroneous offset values for syntax errors during
1444      backslash processing.      backslash processing.
1445    
1446    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1447        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1448    
1449    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1450        caused an overrun.
1451    
1452    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1453        something other than just ASCII characters) inside a group that had an
1454        unlimited repeat caused a loop at compile time (while checking to see
1455        whether the group could match an empty string).
1456    
1457    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1458        [\P{Any}] did so. (Error in the code for printing property names.)
1459    
1460    21. An orphan \E inside a character class could cause a crash.
1461    
1462    22. A repeated capturing bracket such as (A)? could cause a wild memory
1463        reference during compilation.
1464    
1465    23. There are several functions in pcre_compile() that scan along a compiled
1466        expression for various reasons (e.g. to see if it's fixed length for look
1467        behind). There were bugs in these functions when a repeated \p or \P was
1468        present in the pattern. These operators have additional parameters compared
1469        with \d, etc, and these were not being taken into account when moving along
1470        the compiled data. Specifically:
1471    
1472        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1473            length.
1474    
1475        (b) An item such as \pL+ within a repeated group could cause crashes or
1476            loops.
1477    
1478        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1479            "reference to non-existent subpattern" error.
1480    
1481        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1482    
1483    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1484        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1485    
1486    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1487    
1488    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1489        character were causing crashes (broken optimization).
1490    
1491    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1492        \p or \P) caused a compile-time loop.
1493    
1494    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1495        break. For example, the unstudied pattern [\r\n]A does not match the string
1496        "\r\nA" because change 7.0/46 below moves the current point on by two
1497        characters after failing to match at the start. However, the pattern \nA
1498        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1499        the same is true. There doesn't seem any very clean way out of this, but
1500        what I have chosen to do makes the common cases work: PCRE now takes note
1501        of whether there can be an explicit match for \r or \n anywhere in the
1502        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1503        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1504        pattern has explicit CR or LF references.
1505    
1506    29. Added (*CR) etc for changing newline setting at start of pattern.
1507    
1508    
1509  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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