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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
14    
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
23    
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
28    
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
34    
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
38    
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
46    
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
55    
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
59    
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
62    
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
68    
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
72    
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
77    
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
86    
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
90    
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
95    
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
102    
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
106    
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
109    
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
113    
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
116    
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
125    
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
129    
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
136    
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
140    
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
147    
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
151    
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
154    
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
157    
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
161    
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
165    
166    
167    Version 8.12 15-Jan-2011
168    ------------------------
169    
170    1.  Fixed some typos in the markup of the man pages, and wrote a script that
171        checks for such things as part of the documentation building process.
172    
173    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
174        --match-limit and --recursion-limit options (added for 8.11). In
175        particular, this made one of the standard tests fail. (The integer value
176        went into the wrong half of a long int.)
177    
178    3.  If the --colour option was given to pcregrep with -v (invert match), it
179        did strange things, either producing crazy output, or crashing. It should,
180        of course, ignore a request for colour when reporting lines that do not
181        match.
182    
183    4.  Another pcregrep bug caused similar problems if --colour was specified with
184        -M (multiline) and the pattern match finished with a line ending.
185    
186    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
187        matched in multiline mode, the following line was shown as part of the
188        match. This seems wrong, so I have changed it.
189    
190    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
191        the check for further matches in the same line (so they could be coloured)
192        to overrun the end of the current line. If another match was found, it was
193        incorrectly shown (and then shown again when found in the next line).
194    
195    7.  If pcregrep was compiled under Windows, there was a reference to the
196        function pcregrep_exit() before it was defined. I am assuming this was
197        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
198        reported by a user. I've moved the definition above the reference.
199    
200    
201    Version 8.11 10-Dec-2010
202    ------------------------
203    
204    1.  (*THEN) was not working properly if there were untried alternatives prior
205        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
206        backtracked to try for "b" instead of moving to the next alternative branch
207        at the same level (in this case, to look for "c"). The Perl documentation
208        is clear that when (*THEN) is backtracked onto, it goes to the "next
209        alternative in the innermost enclosing group".
210    
211    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
212        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
213        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
214        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
215        (*THEN).
216    
217    3.  If \s appeared in a character class, it removed the VT character from
218        the class, even if it had been included by some previous item, for example
219        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
220        of \s, but is part of the POSIX "space" class.)
221    
222    4.  A partial match never returns an empty string (because you can always
223        match an empty string at the end of the subject); however the checking for
224        an empty string was starting at the "start of match" point. This has been
225        changed to the "earliest inspected character" point, because the returned
226        data for a partial match starts at this character. This means that, for
227        example, /(?<=abc)def/ gives a partial match for the subject "abc"
228        (previously it gave "no match").
229    
230    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
231        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
232        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
233        has an implication that the given string is incomplete (because a partial
234        match is preferred over a full match). For this reason, these items now
235        give a partial match in this situation. [Aside: previously, the one case
236        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
237        match rather than a full match, which was wrong by the old rules, but is
238        now correct.]
239    
240    6.  There was a bug in the handling of #-introduced comments, recognized when
241        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
242        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
243        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
244        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
245        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
246        places in pcre_compile().
247    
248    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
249        comments when looking ahead for named forward references to subpatterns,
250        the only newline sequence it recognized was NL. It now handles newlines
251        according to the set newline convention.
252    
253    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
254        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
255        cater for a lack of strerror(). These oversights have been fixed.
256    
257    9.  Added --match-limit and --recursion-limit to pcregrep.
258    
259    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
260    
261    11. When the -o option was used, pcregrep was setting a return code of 1, even
262        when matches were found, and --line-buffered was not being honoured.
263    
264    12. Added an optional parentheses number to the -o and --only-matching options
265        of pcregrep.
266    
267    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
268        can match an empty string. The code to do it in pcretest and pcredemo
269        needed fixing:
270    
271        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
272            only one byte after an empty string match just before CRLF (this case
273            just got forgotten; "any" and "anycrlf" were OK).
274    
275        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
276            mode when an empty string match preceded an ASCII character followed by
277            a non-ASCII character. (The code for advancing by one character rather
278            than one byte was nonsense.)
279    
280        (c) The pcredemo.c sample program did not have any code at all to handle
281            the cases when CRLF is a valid newline sequence.
282    
283    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
284        as a starting offset was within the subject string. There is now a new
285        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
286        negative or greater than the length of the string. In order to test this,
287        pcretest is extended to allow the setting of negative starting offsets.
288    
289    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
290        starting offset points to the beginning of a UTF-8 character was
291        unnecessarily clumsy. I tidied it up.
292    
293    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
294        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
295    
296    17. Nobody had reported that the --include_dir option, which was added in
297        release 7.7 should have been called --include-dir (hyphen, not underscore)
298        for compatibility with GNU grep. I have changed it to --include-dir, but
299        left --include_dir as an undocumented synonym, and the same for
300        --exclude-dir, though that is not available in GNU grep, at least as of
301        release 2.5.4.
302    
303    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
304        characters from a string of bytes) have been redefined so as not to use
305        loops, in order to improve performance in some environments. At the same
306        time, I abstracted some of the common code into auxiliary macros to save
307        repetition (this should not affect the compiled code).
308    
309    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
310        compile-time error is now given if \c is not followed by an ASCII
311        character, that is, a byte less than 128. (In EBCDIC mode, the code is
312        different, and any byte value is allowed.)
313    
314    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
315        START_OPTIMIZE option, which is now allowed at compile time - but just
316        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
317        to pcregrep and other applications that have no direct access to PCRE
318        options. The new /Y option in pcretest sets this option when calling
319        pcre_compile().
320    
321    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
322        back references. Groups containing recursive back references were forced to
323        be atomic by that change, but in the case of named groups, the amount of
324        memory required was incorrectly computed, leading to "Failed: internal
325        error: code overflow". This has been fixed.
326    
327    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
328        pcretest.c, to avoid build problems in some Borland environments.
329    
330    
331    Version 8.10 25-Jun-2010
332    ------------------------
333    
334    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
335        THEN.
336    
337    2.  (*ACCEPT) was not working when inside an atomic group.
338    
339    3.  Inside a character class, \B is treated as a literal by default, but
340        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
341        causes the error). The code is unchanged, but I tidied the documentation.
342    
343    4.  Inside a character class, PCRE always treated \R and \X as literals,
344        whereas Perl faults them if its -w option is set. I have changed PCRE so
345        that it faults them when PCRE_EXTRA is set.
346    
347    5.  Added support for \N, which always matches any character other than
348        newline. (It is the same as "." when PCRE_DOTALL is not set.)
349    
350    6.  When compiling pcregrep with newer versions of gcc which may have
351        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
352        declared with attribute warn_unused_result" were given. Just casting the
353        result to (void) does not stop the warnings; a more elaborate fudge is
354        needed. I've used a macro to implement this.
355    
356    7.  Minor change to pcretest.c to avoid a compiler warning.
357    
358    8.  Added four artifical Unicode properties to help with an option to make
359        \s etc use properties (see next item). The new properties are: Xan
360        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
361    
362    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
363        use Unicode properties. (*UCP) at the start of a pattern can be used to set
364        this option. Modified pcretest to add /W to test this facility. Added
365        REG_UCP to make it available via the POSIX interface.
366    
367    10. Added --line-buffered to pcregrep.
368    
369    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
370        studied, and the match started with a letter with a code point greater than
371        127 whose first byte was different to the first byte of the other case of
372        the letter, the other case of this starting letter was not recognized
373        (#976).
374    
375    12. If a pattern that was studied started with a repeated Unicode property
376        test, for example, \p{Nd}+, there was the theoretical possibility of
377        setting up an incorrect bitmap of starting bytes, but fortunately it could
378        not have actually happened in practice until change 8 above was made (it
379        added property types that matched character-matching opcodes).
380    
381    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
382        possible starting bytes for non-anchored patterns.
383    
384    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
385        \R, and also a number of cases that involve Unicode properties, both
386        explicit and implicit when PCRE_UCP is set.
387    
388    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
389        input, it could crash or give wrong results if characters with values
390        greater than 0xc0 were present in the subject string. (Detail: it assumed
391        UTF-8 input when processing these items.)
392    
393    16. Added a lot of (int) casts to avoid compiler warnings in systems where
394        size_t is 64-bit (#991).
395    
396    17. Added a check for running out of memory when PCRE is compiled with
397        --disable-stack-for-recursion (#990).
398    
399    18. If the last data line in a file for pcretest does not have a newline on
400        the end, a newline was missing in the output.
401    
402    19. The default pcre_chartables.c file recognizes only ASCII characters (values
403        less than 128) in its various bitmaps. However, there is a facility for
404        generating tables according to the current locale when PCRE is compiled. It
405        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
406        characters, are recognized by isspace() and therefore were getting set in
407        these tables, and indeed these tables seem to approximate to ISO 8859. This
408        caused a problem in UTF-8 mode when pcre_study() was used to create a list
409        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
410        which of course cannot start UTF-8 characters. I have changed the code so
411        that only real ASCII characters (less than 128) and the correct starting
412        bytes for UTF-8 encodings are set for characters greater than 127 when in
413        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
414        altogether.)
415    
416    20. Added the /T option to pcretest so as to be able to run tests with non-
417        standard character tables, thus making it possible to include the tests
418        used for 19 above in the standard set of tests.
419    
420    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
421        reference to a subpattern the other side of a comment that contains an
422        opening parenthesis caused either an internal compiling error, or a
423        reference to the wrong subpattern.
424    
425    
426    Version 8.02 19-Mar-2010
427    ------------------------
428    
429    1.  The Unicode data tables have been updated to Unicode 5.2.0.
430    
431    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
432        configured.
433    
434    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
435        original author of that file, following a query about its status.
436    
437    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
438        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
439    
440    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
441        quantifier applied to a forward-referencing subroutine call, could compile
442        incorrect code or give the error "internal error: previously-checked
443        referenced subpattern not found".
444    
445    6.  Both MS Visual Studio and Symbian OS have problems with initializing
446        variables to point to external functions. For these systems, therefore,
447        pcre_malloc etc. are now initialized to local functions that call the
448        relevant global functions.
449    
450    7.  There were two entries missing in the vectors called coptable and poptable
451        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
452        I've fixed the data, and added a kludgy way of testing at compile time that
453        the lengths are correct (equal to the number of opcodes).
454    
455    8.  Following on from 7, I added a similar kludge to check the length of the
456        eint vector in pcreposix.c.
457    
458    9.  Error texts for pcre_compile() are held as one long string to avoid too
459        much relocation at load time. To find a text, the string is searched,
460        counting zeros. There was no check for running off the end of the string,
461        which could happen if a new error number was added without updating the
462        string.
463    
464    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
465    
466    11. \K was not working if it appeared in an atomic group or in a group that
467        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
468        \K is "not well defined" if used in an assertion. PCRE now accepts it if
469        the assertion is positive, but not if it is negative.
470    
471    12. Change 11 fortuitously reduced the size of the stack frame used in the
472        "match()" function of pcre_exec.c by one pointer. Forthcoming
473        implementation of support for (*MARK) will need an extra pointer on the
474        stack; I have reserved it now, so that the stack frame size does not
475        decrease.
476    
477    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
478        item in branch that calls a recursion is a subroutine call - as in the
479        second branch in the above example - was incorrectly given the compile-
480        time error "recursive call could loop indefinitely" because pcre_compile()
481        was not correctly checking the subroutine for matching a non-empty string.
482    
483    14. The checks for overrunning compiling workspace could trigger after an
484        overrun had occurred. This is a "should never occur" error, but it can be
485        triggered by pathological patterns such as hundreds of nested parentheses.
486        The checks now trigger 100 bytes before the end of the workspace.
487    
488    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
489    
490    
491    Version 8.01 19-Jan-2010
492    ------------------------
493    
494    1.  If a pattern contained a conditional subpattern with only one branch (in
495        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
496        computed the wrong minimum data length (which is of course zero for such
497        subpatterns). This could cause incorrect "no match" results.
498    
499    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
500        the pattern is reset in the first branch, pcre_compile() failed with
501        "internal error: code overflow at offset...". This happened only when
502        the reset was to the original external option setting. (An optimization
503        abstracts leading options settings into an external setting, which was the
504        cause of this.)
505    
506    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
507        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
508        assertion pattern did not match (meaning that the assertion was true), it
509        was incorrectly treated as false if the SKIP had been reached during the
510        matching. This also applied to assertions used as conditions.
511    
512    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
513        assertion subpattern, including such a pattern used as a condition,
514        unpredictable results occurred, instead of the error return
515        PCRE_ERROR_DFA_UITEM.
516    
517    5.  The C++ GlobalReplace function was not working like Perl for the special
518        situation when an empty string is matched. It now does the fancy magic
519        stuff that is necessary.
520    
521    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
522        removed. (These were left over from very, very early versions of PCRE.)
523    
524    7.  Some cosmetic changes to the code to make life easier when compiling it
525        as part of something else:
526    
527        (a) Change DEBUG to PCRE_DEBUG.
528    
529        (b) In pcre_compile(), rename the member of the "branch_chain" structure
530            called "current" as "current_branch", to prevent a collision with the
531            Linux macro when compiled as a kernel module.
532    
533        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
534            prevent a collision with the Linux macro when compiled as a kernel
535            module.
536    
537    8.  In pcre_compile() there are some checks for integer overflows that used to
538        cast potentially large values to (double). This has been changed to that
539        when building, a check for int64_t is made, and if it is found, it is used
540        instead, thus avoiding the use of floating point arithmetic. (There is no
541        other use of FP in PCRE.) If int64_t is not found, the fallback is to
542        double.
543    
544    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
545        2005 (difference between two addresses compared to an unsigned value).
546    
547    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
548        custom one, because of the following reported problem in Windows:
549    
550          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
551              under Win32.
552          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
553              therefore missing the function definition.
554          - The compiler thus generates a "C" signature for the test function.
555          - The linker fails to find the "C" function.
556          - PCRE fails to configure if asked to do so against libbz2.
557    
558    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
559        messages were output:
560    
561          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
562          rerunning libtoolize, to keep the correct libtool macros in-tree.
563          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
564    
565        I have done both of these things.
566    
567    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
568        most of the time, it *can* run out if it is given a pattern that contains a
569        runaway infinite recursion. I updated the discussion in the pcrestack man
570        page.
571    
572    13. Now that we have gone to the x.xx style of version numbers, the minor
573        version may start with zero. Using 08 or 09 is a bad idea because users
574        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
575        interpreted as invalid octal numbers. I've updated the previous comment in
576        configure.ac, and also added a check that gives an error if 08 or 09 are
577        used.
578    
579    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
580        causing partial matching to fail when the end of the subject matched \W
581        in a UTF-8 pattern where \W was quantified with a minimum of 3.
582    
583    15. There were some discrepancies between the declarations in pcre_internal.h
584        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
585        their definitions. The declarations used "const uschar *" and the
586        definitions used USPTR. Even though USPTR is normally defined as "const
587        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
588        reported that: "This difference in casting confuses some C++ compilers, for
589        example, SunCC recognizes above declarations as different functions and
590        generates broken code for hbpcre." I have changed the declarations to use
591        USPTR.
592    
593    16. GNU libtool is named differently on some systems. The autogen.sh script now
594        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
595        (FreeBSD).
596    
597    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
598        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
599        comment: "Figure out how to create a longlong from a string: strtoll and
600        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
601        instance, but it only takes 2 args instead of 3!"
602    
603    18. A subtle bug concerned with back references has been fixed by a change of
604        specification, with a corresponding code fix. A pattern such as
605        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
606        refers, was giving matches when it shouldn't. For example, xa=xaaa would
607        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
608        same bug. Such groups have to be quantified to be useful, or contained
609        inside another quantified group. (If there's no repetition, the reference
610        can never match.) The problem arises because, having left the group and
611        moved on to the rest of the pattern, a later failure that backtracks into
612        the group uses the captured value from the final iteration of the group
613        rather than the correct earlier one. I have fixed this in PCRE by forcing
614        any group that contains a reference to itself to be an atomic group; that
615        is, there cannot be any backtracking into it once it has completed. This is
616        similar to recursive and subroutine calls.
617    
618    
619    Version 8.00 19-Oct-09
620    ----------------------
621    
622    1.  The table for translating pcre_compile() error codes into POSIX error codes
623        was out-of-date, and there was no check on the pcre_compile() error code
624        being within the table. This could lead to an OK return being given in
625        error.
626    
627    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
628        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
629        in a Windows environment.
630    
631    3.  The pcregrep --count option prints the count for each file even when it is
632        zero, as does GNU grep. However, pcregrep was also printing all files when
633        --files-with-matches was added. Now, when both options are given, it prints
634        counts only for those files that have at least one match. (GNU grep just
635        prints the file name in this circumstance, but including the count seems
636        more useful - otherwise, why use --count?) Also ensured that the
637        combination -clh just lists non-zero counts, with no names.
638    
639    4.  The long form of the pcregrep -F option was incorrectly implemented as
640        --fixed_strings instead of --fixed-strings. This is an incompatible change,
641        but it seems right to fix it, and I didn't think it was worth preserving
642        the old behaviour.
643    
644    5.  The command line items --regex=pattern and --regexp=pattern were not
645        recognized by pcregrep, which required --regex pattern or --regexp pattern
646        (with a space rather than an '='). The man page documented the '=' forms,
647        which are compatible with GNU grep; these now work.
648    
649    6.  No libpcreposix.pc file was created for pkg-config; there was just
650        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
651    
652    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
653        when UCP support is not needed, by modifying the Python script that
654        generates it from Unicode data files. This should not matter if the module
655        is correctly used as a library, but I received one complaint about 50K of
656        unwanted data. My guess is that the person linked everything into his
657        program rather than using a library. Anyway, it does no harm.
658    
659    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
660        was a minimum greater than 1 for a wide character in a possessive
661        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
662        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
663        character. Chaos in the form of incorrect output or a compiling loop could
664        result.
665    
666    9.  The restrictions on what a pattern can contain when partial matching is
667        requested for pcre_exec() have been removed. All patterns can now be
668        partially matched by this function. In addition, if there are at least two
669        slots in the offset vector, the offset of the earliest inspected character
670        for the match and the offset of the end of the subject are set in them when
671        PCRE_ERROR_PARTIAL is returned.
672    
673    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
674        synonymous with PCRE_PARTIAL, for backwards compatibility, and
675        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
676        and may be more useful for multi-segment matching.
677    
678    11. Partial matching with pcre_exec() is now more intuitive. A partial match
679        used to be given if ever the end of the subject was reached; now it is
680        given only if matching could not proceed because another character was
681        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
682        string "Z", which now yields "no match" instead of "partial match". In the
683        case of pcre_dfa_exec(), "no match" is given if every matching path for the
684        final character ended with (*FAIL).
685    
686    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
687        if the pattern had a "must contain" character that was already found in the
688        earlier partial match, unless partial matching was again requested. For
689        example, with the pattern /dog.(body)?/, the "must contain" character is
690        "g". If the first part-match was for the string "dog", restarting with
691        "sbody" failed. This bug has been fixed.
692    
693    13. The string returned by pcre_dfa_exec() after a partial match has been
694        changed so that it starts at the first inspected character rather than the
695        first character of the match. This makes a difference only if the pattern
696        starts with a lookbehind assertion or \b or \B (\K is not supported by
697        pcre_dfa_exec()). It's an incompatible change, but it makes the two
698        matching functions compatible, and I think it's the right thing to do.
699    
700    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
701        so that the demonstration program is easily available in environments where
702        PCRE has not been installed from source.
703    
704    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
705        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
706        library.
707    
708    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
709        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
710        is not the first non-POSIX option to be added. Clearly some people find
711        these options useful.
712    
713    17. If a caller to the POSIX matching function regexec() passes a non-zero
714        value for nmatch with a NULL value for pmatch, the value of
715        nmatch is forced to zero.
716    
717    18. RunGrepTest did not have a test for the availability of the -u option of
718        the diff command, as RunTest does. It now checks in the same way as
719        RunTest, and also checks for the -b option.
720    
721    19. If an odd number of negated classes containing just a single character
722        interposed, within parentheses, between a forward reference to a named
723        subpattern and the definition of the subpattern, compilation crashed with
724        an internal error, complaining that it could not find the referenced
725        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
726        [The bug was that it was starting one character too far in when skipping
727        over the character class, thus treating the ] as data rather than
728        terminating the class. This meant it could skip too much.]
729    
730    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
731        /g option in pcretest when the pattern contains \K, which makes it possible
732        to have an empty string match not at the start, even when the pattern is
733        anchored. Updated pcretest and pcredemo to use this option.
734    
735    21. If the maximum number of capturing subpatterns in a recursion was greater
736        than the maximum at the outer level, the higher number was returned, but
737        with unset values at the outer level. The correct (outer level) value is
738        now given.
739    
740    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
741        PCRE did not set those parentheses (unlike Perl). I have now found a way to
742        make it do so. The string so far is captured, making this feature
743        compatible with Perl.
744    
745    23. The tests have been re-organized, adding tests 11 and 12, to make it
746        possible to check the Perl 5.10 features against Perl 5.10.
747    
748    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
749        pattern matches a fixed length string. PCRE did not allow this; now it
750        does. Neither allows recursion.
751    
752    25. I finally figured out how to implement a request to provide the minimum
753        length of subject string that was needed in order to match a given pattern.
754        (It was back references and recursion that I had previously got hung up
755        on.) This code has now been added to pcre_study(); it finds a lower bound
756        to the length of subject needed. It is not necessarily the greatest lower
757        bound, but using it to avoid searching strings that are too short does give
758        some useful speed-ups. The value is available to calling programs via
759        pcre_fullinfo().
760    
761    26. While implementing 25, I discovered to my embarrassment that pcretest had
762        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
763        study optimizations had never been tested with that matching function.
764        Oops. What is worse, even when it was passed study data, there was a bug in
765        pcre_dfa_exec() that meant it never actually used it. Double oops. There
766        were also very few tests of studied patterns with pcre_dfa_exec().
767    
768    27. If (?| is used to create subpatterns with duplicate numbers, they are now
769        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
770        on the other side of the coin, they are no longer allowed to have different
771        names, because these cannot be distinguished in PCRE, and this has caused
772        confusion. (This is a difference from Perl.)
773    
774    28. When duplicate subpattern names are present (necessarily with different
775        numbers, as required by 27 above), and a test is made by name in a
776        conditional pattern, either for a subpattern having been matched, or for
777        recursion in such a pattern, all the associated numbered subpatterns are
778        tested, and the overall condition is true if the condition is true for any
779        one of them. This is the way Perl works, and is also more like the way
780        testing by number works.
781    
782    
783    Version 7.9 11-Apr-09
784    ---------------------
785    
786    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
787        (pcretest), all targets were linked against these libraries. This included
788        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
789        libraries. This caused unwanted dependencies to be created. This problem
790        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
791        pcretest is linked with readline.
792    
793    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
794        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
795        moved outside it again, because FALSE and TRUE are already defined in AIX,
796        but BOOL is not.
797    
798    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
799        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
800    
801    4.  The pcregrep documentation said spaces were inserted as well as colons (or
802        hyphens) following file names and line numbers when outputting matching
803        lines. This is not true; no spaces are inserted. I have also clarified the
804        wording for the --colour (or --color) option.
805    
806    5.  In pcregrep, when --colour was used with -o, the list of matching strings
807        was not coloured; this is different to GNU grep, so I have changed it to be
808        the same.
809    
810    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
811        each matching line was coloured. Now it goes on to look for further matches
812        of any of the test patterns, which is the same behaviour as GNU grep.
813    
814    7.  A pattern that could match an empty string could cause pcregrep to loop; it
815        doesn't make sense to accept an empty string match in pcregrep, so I have
816        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
817        seems to be how GNU grep behaves.
818    
819    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
820        start or after a newline", because the conditional assertion was not being
821        correctly handled. The rule now is that both the assertion and what follows
822        in the first alternative must satisfy the test.
823    
824    9.  If auto-callout was enabled in a pattern with a conditional group whose
825        condition was an assertion, PCRE could crash during matching, both with
826        pcre_exec() and pcre_dfa_exec().
827    
828    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
829        used for matching.
830    
831    11. Unicode property support in character classes was not working for
832        characters (bytes) greater than 127 when not in UTF-8 mode.
833    
834    12. Added the -M command line option to pcretest.
835    
836    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
837    
838    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
839    
840    16. Added comments and documentation about mis-use of no_arg in the C++
841        wrapper.
842    
843    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
844        from Martin Jerabek that uses macro names for all relevant character and
845        string constants.
846    
847    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
848        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
849        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
850        these, but not everybody uses configure.
851    
852    19. A conditional group that had only one branch was not being correctly
853        recognized as an item that could match an empty string. This meant that an
854        enclosing group might also not be so recognized, causing infinite looping
855        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
856        with the subject "ab", where knowledge that the repeated group can match
857        nothing is needed in order to break the loop.
858    
859    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
860        exec(), but without supplying a callout function, matching went wrong.
861    
862    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
863        leak if the size of the offset vector was greater than 30. When the vector
864        is smaller, the saved offsets during recursion go onto a local stack
865        vector, but for larger vectors malloc() is used. It was failing to free
866        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
867        error, in fact).
868    
869    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
870        heapframe that is used only when UTF-8 support is enabled. This caused no
871        problem, but was untidy.
872    
873    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
874        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
875        included within another project.
876    
877    24. Steven Van Ingelgem's patches to add more options to the CMake support,
878        slightly modified by me:
879    
880          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
881              not building pcregrep.
882    
883          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
884              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
885    
886    25. Forward references, both numeric and by name, in patterns that made use of
887        duplicate group numbers, could behave incorrectly or give incorrect errors,
888        because when scanning forward to find the reference group, PCRE was not
889        taking into account the duplicate group numbers. A pattern such as
890        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
891    
892    26. Changed a few more instances of "const unsigned char *" to USPTR, making
893        the feature of a custom pointer more persuasive (as requested by a user).
894    
895    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
896        pcretest.c, inside #ifndefs, because it seems they are sometimes already
897        pre-defined.
898    
899    28. Added support for (*UTF8) at the start of a pattern.
900    
901    29. Arrange for flags added by the "release type" setting in CMake to be shown
902        in the configuration summary.
903    
904    
905    Version 7.8 05-Sep-08
906    ---------------------
907    
908    1.  Replaced UCP searching code with optimized version as implemented for Ad
909        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
910        stage table and inline lookup instead of a function, giving speed ups of 2
911        to 5 times on some simple patterns that I tested. Permission was given to
912        distribute the MultiStage2.py script that generates the tables (it's not in
913        the tarball, but is in the Subversion repository).
914    
915    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
916        scripts.
917    
918    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
919        a group with a zero qualifier. The result of the study could be incorrect,
920        or the function might crash, depending on the pattern.
921    
922    4.  Caseless matching was not working for non-ASCII characters in back
923        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
924        It now works when Unicode Property Support is available.
925    
926    5.  In pcretest, an escape such as \x{de} in the data was always generating
927        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
928        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
929        truncation.
930    
931    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
932    
933    7.  Added two (int) casts to pcregrep when printing the difference of two
934        pointers, in case they are 64-bit values.
935    
936    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
937        test 2 if it fails.
938    
939    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
940        and a #define of that name to empty if it is not externally set. This is to
941        allow users of MSVC to set it if necessary.
942    
943    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
944        the convenience functions in the pcre_get.c source file.
945    
946    11. An option change at the start of a pattern that had top-level alternatives
947        could cause overwriting and/or a crash. This command provoked a crash in
948        some environments:
949    
950          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
951    
952        This potential security problem was recorded as CVE-2008-2371.
953    
954    12. For a pattern where the match had to start at the beginning or immediately
955        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
956        pcre_dfa_exec() could read past the end of the passed subject if there was
957        no match. To help with detecting such bugs (e.g. with valgrind), I modified
958        pcretest so that it places the subject at the end of its malloc-ed buffer.
959    
960    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
961        exec() might read past the end of the data buffer in UTF-8 mode.
962    
963    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
964        the data contained the byte 0x85 as part of a UTF-8 character within its
965        first line. This applied both to normal and DFA matching.
966    
967    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
968        /^[^d]*?$/8 failed to match "abc".
969    
970    16. Added a missing copyright notice to pcrecpp_internal.h.
971    
972    17. Make it more clear in the documentation that values returned from
973        pcre_exec() in ovector are byte offsets, not character counts.
974    
975    18. Tidied a few places to stop certain compilers from issuing warnings.
976    
977    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
978        supplied by Stefan Weber. I made a further small update for 7.8 because
979        there is a change of source arrangements: the pcre_searchfuncs.c module is
980        replaced by pcre_ucd.c.
981    
982    
983    Version 7.7 07-May-08
984    ---------------------
985    
986    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
987        a string to a long long, pretend we don't even have a long long." This is
988        done by checking for the strtoq, strtoll, and _strtoi64 functions.
989    
990    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
991        pre-7.6 versions, which defined a global no_arg variable instead of putting
992        it in the RE class. (See also #8 below.)
993    
994    3.  Remove a line of dead code, identified by coverity and reported by Nuno
995        Lopes.
996    
997    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
998    
999        (1) The include/exclude patterns were being applied to the whole pathnames
1000            of files, instead of just to the final components.
1001    
1002        (2) If there was more than one level of directory, the subdirectories were
1003            skipped unless they satisfied the include/exclude conditions. This is
1004            inconsistent with GNU grep (and could even be seen as contrary to the
1005            pcregrep specification - which I improved to make it absolutely clear).
1006            The action now is always to scan all levels of directory, and just
1007            apply the include/exclude patterns to regular files.
1008    
1009    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1010        --exclude_dir in the tests to avoid scanning .svn directories.
1011    
1012    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1013        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1014        doesn't support NULs in patterns.
1015    
1016    7.  Added some missing "const"s to declarations of static tables in
1017        pcre_compile.c and pcre_dfa_exec.c.
1018    
1019    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1020        caused by fix #2  above. (Subsequently also a second patch to fix the
1021        first patch. And a third patch - this was a messy problem.)
1022    
1023    9.  Applied Craig's patch to remove the use of push_back().
1024    
1025    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1026        matching function regexec().
1027    
1028    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1029        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1030        references. PCRE supports relative numbers with this syntax (I don't think
1031        Oniguruma does).
1032    
1033    12. Previously, a group with a zero repeat such as (...){0} was completely
1034        omitted from the compiled regex. However, this means that if the group
1035        was called as a subroutine from elsewhere in the pattern, things went wrong
1036        (an internal error was given). Such groups are now left in the compiled
1037        pattern, with a new opcode that causes them to be skipped at execution
1038        time.
1039    
1040    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1041        to the way PCRE behaves:
1042    
1043        (a) A lone ] character is dis-allowed (Perl treats it as data).
1044    
1045        (b) A back reference to an unmatched subpattern matches an empty string
1046            (Perl fails the current match path).
1047    
1048        (c) A data ] in a character class must be notated as \] because if the
1049            first data character in a class is ], it defines an empty class. (In
1050            Perl it is not possible to have an empty class.) The empty class []
1051            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1052            The negative empty class [^] matches any one character, independently
1053            of the DOTALL setting.
1054    
1055    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1056        non-existent subpattern following a character class starting with ']' and
1057        containing () gave an internal compiling error instead of "reference to
1058        non-existent subpattern". Fortunately, when the pattern did exist, the
1059        compiled code was correct. (When scanning forwards to check for the
1060        existencd of the subpattern, it was treating the data ']' as terminating
1061        the class, so got the count wrong. When actually compiling, the reference
1062        was subsequently set up correctly.)
1063    
1064    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1065        it was being rejected as not supported by pcre_dfa_exec(), even though
1066        other assertions are supported. I have made pcre_dfa_exec() support
1067        (*FAIL).
1068    
1069    16. The implementation of 13c above involved the invention of a new opcode,
1070        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1071        cannot be changed at match time, I realized I could make a small
1072        improvement to matching performance by compiling OP_ALLANY instead of
1073        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1074        on the OP_ANY path.
1075    
1076    17. Compiling pcretest on Windows with readline support failed without the
1077        following two fixes: (1) Make the unistd.h include conditional on
1078        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1079    
1080    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1081        ncurses library to be included for pcretest when ReadLine support is
1082        requested, but also to allow for it to be overridden. This patch came from
1083        Daniel Bergström.
1084    
1085    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1086        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1087        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1088        spotting this.
1089    
1090    
1091    Version 7.6 28-Jan-08
1092    ---------------------
1093    
1094    1.  A character class containing a very large number of characters with
1095        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1096        overflow.
1097    
1098    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1099        HAVE_LONG_LONG is not defined.
1100    
1101    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1102        bring them up to date and include new features. This patch includes:
1103    
1104        - Fixed PH's badly added libz and libbz2 support.
1105        - Fixed a problem with static linking.
1106        - Added pcredemo. [But later removed - see 7 below.]
1107        - Fixed dftables problem and added an option.
1108        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1109            HAVE_LONG_LONG.
1110        - Added readline support for pcretest.
1111        - Added an listing of the option settings after cmake has run.
1112    
1113    4.  A user submitted a patch to Makefile that makes it easy to create
1114        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1115        Makefile.am that cause it to include this special target, without
1116        affecting anything else. Note that the same mingw target plus all
1117        the other distribution libraries and programs are now supported
1118        when configuring with CMake (see 6 below) instead of with
1119        Configure/Make.
1120    
1121    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1122        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1123        exported in the Windows port". It has not yet been confirmed that the patch
1124        solves the problem, but it does no harm.
1125    
1126    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1127        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1128        with CMake, and also correct the comment about stack recursion.
1129    
1130    7.  Remove the automatic building of pcredemo from the ./configure system and
1131        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1132        of a program that users should build themselves after PCRE is installed, so
1133        building it automatically is not really right. What is more, it gave
1134        trouble in some build environments.
1135    
1136    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1137    
1138    
1139    Version 7.5 10-Jan-08
1140    ---------------------
1141    
1142    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1143        values in parens when parsing an RE using the C++ wrapper."
1144    
1145    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1146        Characters greater than 255 were excluded from the class instead of being
1147        included.
1148    
1149    3.  The same bug as (2) above applied to negated POSIX classes such as
1150        [:^space:].
1151    
1152    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1153        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1154        I have changed it.
1155    
1156    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1157        first named subpattern) and a construct such as (?&a) would reference the
1158        first named subpattern whose name started with "a" (in other words, the
1159        length check was missing). Both these problems are fixed. "Subpattern name
1160        expected" is now given for (?&) (a zero-length name), and this patch also
1161        makes it give the same error for \k'' (previously it complained that that
1162        was a reference to a non-existent subpattern).
1163    
1164    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1165        this is right because (?- can be followed by option settings as well as by
1166        digits. I have, however, made the messages clearer.
1167    
1168    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1169        than the number used in the conditional) now cause a compile-time error.
1170        This is actually not compatible with Perl, which accepts such patterns, but
1171        treats the conditional as always being FALSE (as PCRE used to), but it
1172        seems to me that giving a diagnostic is better.
1173    
1174    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1175        and messages.
1176    
1177    9.  Fix two occurrences of "backslash" in comments that should have been
1178        "backspace".
1179    
1180    10. Remove two redundant lines of code that can never be obeyed (their function
1181        was moved elsewhere).
1182    
1183    11. The program that makes PCRE's Unicode character property table had a bug
1184        which caused it to generate incorrect table entries for sequences of
1185        characters that have the same character type, but are in different scripts.
1186        It amalgamated them into a single range, with the script of the first of
1187        them. In other words, some characters were in the wrong script. There were
1188        thirteen such cases, affecting characters in the following ranges:
1189    
1190          U+002b0 - U+002c1
1191          U+0060c - U+0060d
1192          U+0061e - U+00612
1193          U+0064b - U+0065e
1194          U+0074d - U+0076d
1195          U+01800 - U+01805
1196          U+01d00 - U+01d77
1197          U+01d9b - U+01dbf
1198          U+0200b - U+0200f
1199          U+030fc - U+030fe
1200          U+03260 - U+0327f
1201          U+0fb46 - U+0fbb1
1202          U+10450 - U+1049d
1203    
1204    12. The -o option (show only the matching part of a line) for pcregrep was not
1205        compatible with GNU grep in that, if there was more than one match in a
1206        line, it showed only the first of them. It now behaves in the same way as
1207        GNU grep.
1208    
1209    13. If the -o and -v options were combined for pcregrep, it printed a blank
1210        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1211        does the same. The return code can be used to tell if there were any
1212        non-matching lines.
1213    
1214    14. Added --file-offsets and --line-offsets to pcregrep.
1215    
1216    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1217        infinitely looping recursion. The bug was that positive lookaheads were not
1218        being skipped when checking for a possible empty match (negative lookaheads
1219        and both kinds of lookbehind were skipped).
1220    
1221    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1222        inclusion of <windows.h> to before rather than after the definition of
1223        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1224    
1225    17. Specifying a possessive quantifier with a specific limit for a Unicode
1226        character property caused pcre_compile() to compile bad code, which led at
1227        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1228        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1229        caused the error; without that there was no problem.
1230    
1231    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1232    
1233    19. Added --enable-pcretest-libreadline.
1234    
1235    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1236        RE::GlobalReplace(). As a result, the number of replacements returned was
1237        double what it should be. I removed one of the increments, but Craig sent a
1238        later patch that removed the other one (the right fix) and added unit tests
1239        that check the return values (which was not done before).
1240    
1241    21. Several CMake things:
1242    
1243        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1244            the names libpcre and libpcreposix, not just pcre and pcreposix.
1245    
1246        (2) The above change means that pcretest and pcregrep are now correctly
1247            linked with the newly-built libraries, not previously installed ones.
1248    
1249        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1250    
1251    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1252        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1253        UTF-8 newline character). The key issue is that the pattern starts .*;
1254        this means that the match must be either at the beginning, or after a
1255        newline. The bug was in the code for advancing after a failed match and
1256        checking that the new position followed a newline. It was not taking
1257        account of UTF-8 characters correctly.
1258    
1259    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1260        character classes. PCRE was not treating the sequence [:...:] as a
1261        character class unless the ... were all letters. Perl, however, seems to
1262        allow any characters between [: and :], though of course it rejects as
1263        unknown any "names" that contain non-letters, because all the known class
1264        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1265        for example, whereas PCRE did not - it did not recognize a POSIX character
1266        class. This seemed a bit dangerous, so the code has been changed to be
1267        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1268        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1269        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1270        Perl does, and where it didn't before.
1271    
1272    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1273        Windows environments %n is disabled by default.
1274    
1275    
1276    Version 7.4 21-Sep-07
1277    ---------------------
1278    
1279    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1280        means that a class such as [\s] counted as "explicit reference to CR or
1281        LF". That isn't really right - the whole point of the change was to try to
1282        help when there was an actual mention of one of the two characters. So now
1283        the change happens only if \r or \n (or a literal CR or LF) character is
1284        encountered.
1285    
1286    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1287        of both had grown to the point where there were only 3 bits left.
1288        Fortunately, there was spare space in the data structure, and so I have
1289        moved the internal flags into a new 16-bit field to free up more option
1290        bits.
1291    
1292    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1293        but did not set the internal JCHANGED flag - either of these is enough to
1294        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1295        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1296        start sets both bits.
1297    
1298    4.  Added options (at build time, compile time, exec time) to change \R from
1299        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1300    
1301    5.  doc/pcresyntax.html was missing from the distribution.
1302    
1303    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1304        compatibility, even though it is no longer used.
1305    
1306    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1307        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1308        windows.h file is present (where different names are used). [This was
1309        reversed later after testing - see 16 below.]
1310    
1311    8.  Changed all #include <config.h> to #include "config.h". There were also
1312        some further <pcre.h> cases that I changed to "pcre.h".
1313    
1314    9.  When pcregrep was used with the --colour option, it missed the line ending
1315        sequence off the lines that it output.
1316    
1317    10. It was pointed out to me that arrays of string pointers cause lots of
1318        relocations when a shared library is dynamically loaded. A technique of
1319        using a single long string with a table of offsets can drastically reduce
1320        these. I have refactored PCRE in four places to do this. The result is
1321        dramatic:
1322    
1323          Originally:                          290
1324          After changing UCP table:            187
1325          After changing error message table:   43
1326          After changing table of "verbs"       36
1327          After changing table of Posix names   22
1328    
1329        Thanks to the folks working on Gregex for glib for this insight.
1330    
1331    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1332        unicode-properties was also set.
1333    
1334    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1335    
1336    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1337        checked only for CRLF.
1338    
1339    14. Added casts to pcretest.c to avoid compiler warnings.
1340    
1341    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1342    
1343    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1344        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1345        entirely. This removes changes made in 7 above.
1346    
1347    17. The CMake files have been updated, and there is now more information about
1348        building with CMake in the NON-UNIX-USE document.
1349    
1350    
1351    Version 7.3 28-Aug-07
1352    ---------------------
1353    
1354     1. In the rejigging of the build system that eventually resulted in 7.1, the
1355        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1356        brackets there is not right, since it causes compilers to look for an
1357        installed pcre.h, not the version that is in the source that is being
1358        compiled (which of course may be different). I have changed it back to:
1359    
1360          #include "pcre.h"
1361    
1362        I have a vague recollection that the change was concerned with compiling in
1363        different directories, but in the new build system, that is taken care of
1364        by the VPATH setting the Makefile.
1365    
1366     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1367        when the subject happened to end in the byte 0x85 (e.g. if the last
1368        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1369        characters but of course it shouldn't be taken as a newline when it is part
1370        of another character. The bug was that, for an unlimited repeat of . in
1371        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1372        characters when looking for a newline.
1373    
1374     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1375    
1376     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1377        in debug output.
1378    
1379     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1380        long printing in the pcrecpp unittest when running under MinGW.
1381    
1382     6. ESC_K was left out of the EBCDIC table.
1383    
1384     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1385        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1386        limit also applies to "virtual nesting" when a pattern is recursive, and in
1387        this case 1000 isn't so big. I have been able to remove this limit at the
1388        expense of backing off one optimization in certain circumstances. Normally,
1389        when pcre_exec() would call its internal match() function recursively and
1390        immediately return the result unconditionally, it uses a "tail recursion"
1391        feature to save stack. However, when a subpattern that can match an empty
1392        string has an unlimited repetition quantifier, it no longer makes this
1393        optimization. That gives it a stack frame in which to save the data for
1394        checking that an empty string has been matched. Previously this was taken
1395        from the 1000-entry workspace that had been reserved. So now there is no
1396        explicit limit, but more stack is used.
1397    
1398     8. Applied Daniel's patches to solve problems with the import/export magic
1399        syntax that is required for Windows, and which was going wrong for the
1400        pcreposix and pcrecpp parts of the library. These were overlooked when this
1401        problem was solved for the main library.
1402    
1403     9. There were some crude static tests to avoid integer overflow when computing
1404        the size of patterns that contain repeated groups with explicit upper
1405        limits. As the maximum quantifier is 65535, the maximum group length was
1406        set at 30,000 so that the product of these two numbers did not overflow a
1407        32-bit integer. However, it turns out that people want to use groups that
1408        are longer than 30,000 bytes (though not repeat them that many times).
1409        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1410        made it possible to implement the integer overflow checks in a much more
1411        dynamic way, which I have now done. The artificial limitation on group
1412        length has been removed - we now have only the limit on the total length of
1413        the compiled pattern, which depends on the LINK_SIZE setting.
1414    
1415    10. Fixed a bug in the documentation for get/copy named substring when
1416        duplicate names are permitted. If none of the named substrings are set, the
1417        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1418        empty string.
1419    
1420    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1421        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1422        because the ] is interpreted as the first data character and the
1423        terminating ] is not found. PCRE has been made compatible with Perl in this
1424        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1425        cause memory overwriting.
1426    
1427    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1428        string has been matched (to stop an infinite loop). It was not recognizing
1429        a conditional subpattern that could match an empty string if that
1430        subpattern was within another subpattern. For example, it looped when
1431        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1432        condition was not nested. This bug has been fixed.
1433    
1434    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1435        past the start of the subject in the presence of bytes with the top bit
1436        set, for example "\x8aBCD".
1437    
1438    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1439        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1440    
1441    14. Optimized (?!) to (*FAIL).
1442    
1443    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1444        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1445        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1446        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1447        does: it's just the validity check that is more restrictive.
1448    
1449    16. Inserted checks for integer overflows during escape sequence (backslash)
1450        processing, and also fixed erroneous offset values for syntax errors during
1451        backslash processing.
1452    
1453    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1454        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1455    
1456    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1457        caused an overrun.
1458    
1459    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1460        something other than just ASCII characters) inside a group that had an
1461        unlimited repeat caused a loop at compile time (while checking to see
1462        whether the group could match an empty string).
1463    
1464    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1465        [\P{Any}] did so. (Error in the code for printing property names.)
1466    
1467    21. An orphan \E inside a character class could cause a crash.
1468    
1469    22. A repeated capturing bracket such as (A)? could cause a wild memory
1470        reference during compilation.
1471    
1472    23. There are several functions in pcre_compile() that scan along a compiled
1473        expression for various reasons (e.g. to see if it's fixed length for look
1474        behind). There were bugs in these functions when a repeated \p or \P was
1475        present in the pattern. These operators have additional parameters compared
1476        with \d, etc, and these were not being taken into account when moving along
1477        the compiled data. Specifically:
1478    
1479        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1480            length.
1481    
1482        (b) An item such as \pL+ within a repeated group could cause crashes or
1483            loops.
1484    
1485        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1486            "reference to non-existent subpattern" error.
1487    
1488        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1489    
1490    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1491        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1492    
1493    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1494    
1495    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1496        character were causing crashes (broken optimization).
1497    
1498    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1499        \p or \P) caused a compile-time loop.
1500    
1501    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1502        break. For example, the unstudied pattern [\r\n]A does not match the string
1503        "\r\nA" because change 7.0/46 below moves the current point on by two
1504        characters after failing to match at the start. However, the pattern \nA
1505        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1506        the same is true. There doesn't seem any very clean way out of this, but
1507        what I have chosen to do makes the common cases work: PCRE now takes note
1508        of whether there can be an explicit match for \r or \n anywhere in the
1509        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1510        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1511        pattern has explicit CR or LF references.
1512    
1513    29. Added (*CR) etc for changing newline setting at start of pattern.
1514    
1515    
1516    Version 7.2 19-Jun-07
1517    ---------------------
1518    
1519     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1520        which is apparently normally available under Windows.
1521    
1522     2. Re-jig the pcregrep tests with different newline settings in an attempt
1523        to make them independent of the local environment's newline setting.
1524    
1525     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1526    
1527     4. Some of the "internals" tests were previously cut out when the link size
1528        was not 2, because the output contained actual offsets. The recent new
1529        "Z" feature of pcretest means that these can be cut out, making the tests
1530        usable with all link sizes.
1531    
1532     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1533        stack recursion. This gives a massive performance boost under BSD, but just
1534        a small improvement under Linux. However, it saves one field in the frame
1535        in all cases.
1536    
1537     6. Added more features from the forthcoming Perl 5.10:
1538    
1539        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1540            recursion call. It refers to the nth most recently opened parentheses.
1541    
1542        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1543            to be opened parentheses.
1544    
1545        (c) Conditions that refer to capturing parentheses can be specified
1546            relatively, for example, (?(-2)... or (?(+3)...
1547    
1548        (d) \K resets the start of the current match so that everything before
1549            is not part of it.
1550    
1551        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1552    
1553        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1554            reference syntax.
1555    
1556        (g) (?| introduces a group in which the numbering of parentheses in each
1557            alternative starts with the same number.
1558    
1559        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1560    
1561     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1562        PCRE_INFO_JCHANGED.
1563    
1564     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1565        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1566        for detecting groups that can match an empty string.
1567    
1568     9. A pattern with a very large number of alternatives (more than several
1569        hundred) was running out of internal workspace during the pre-compile
1570        phase, where pcre_compile() figures out how much memory will be needed. A
1571        bit of new cunning has reduced the workspace needed for groups with
1572        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1573        workspace instead of running out of the 4096 that are available.
1574    
1575    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1576    
1577    11. Applied patch from Google to remove an optimization that didn't quite work.
1578        The report of the bug said:
1579    
1580          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1581          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1582          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1583    
1584    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1585        it matched the wrong number of bytes.
1586    
1587    
1588    Version 7.1 24-Apr-07
1589    ---------------------
1590    
1591     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1592        that is more "standard", making use of automake and other Autotools. There
1593        is some re-arrangement of the files and adjustment of comments consequent
1594        on this.
1595    
1596     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1597        for recursive directory scanning broke on some systems because the files
1598        are not scanned in any specific order and on different systems the order
1599        was different. A call to "sort" has been inserted into RunGrepTest for the
1600        approprate test as a short-term fix. In the longer term there may be an
1601        alternative.
1602    
1603     3. I had an email from Eric Raymond about problems translating some of PCRE's
1604        man pages to HTML (despite the fact that I distribute HTML pages, some
1605        people do their own conversions for various reasons). The problems
1606        concerned the use of low-level troff macros .br and .in. I have therefore
1607        removed all such uses from the man pages (some were redundant, some could
1608        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1609        HTML has been updated to handle .nf/.fi and to complain if it encounters
1610        .br or .in.
1611    
1612     4. Updated comments in configure.ac that get placed in config.h.in and also
1613        arranged for config.h to be included in the distribution, with the name
1614        config.h.generic, for the benefit of those who have to compile without
1615        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1616    
1617     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1618        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1619        makevp.bat for the current PCRE, using the additional files
1620        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1621    
1622     6. A Windows user reported a minor discrepancy with test 2, which turned out
1623        to be caused by a trailing space on an input line that had got lost in his
1624        copy. The trailing space was an accident, so I've just removed it.
1625    
1626     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1627        that is needed.
1628    
1629     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1630        as "const" (a) because they are and (b) because it helps the PHP
1631        maintainers who have recently made a script to detect big data structures
1632        in the php code that should be moved to the .rodata section. I remembered
1633        to update Builducptable as well, so it won't revert if ucptable.h is ever
1634        re-created.
1635    
1636     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1637        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1638        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1639        support is not required. This saves 1.5-2K of code, which is important in
1640        some applications.
1641    
1642        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1643        so as not to refer to the tables, even though these functions will never be
1644        called when UTF-8 support is disabled. Otherwise there are problems with a
1645        shared library.
1646    
1647    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1648    
1649        (a) It was defining its arguments as char * instead of void *.
1650    
1651        (b) It was assuming that all moves were upwards in memory; this was true
1652            a long time ago when I wrote it, but is no longer the case.
1653    
1654        The emulated memove() is provided for those environments that have neither
1655        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1656        is clearly not the case, as these two bugs were recently reported.
1657    
1658    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1659        and Detrail to create the HTML documentation, the .txt form of the man
1660        pages, and it removes trailing spaces from listed files. It also creates
1661        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1662        case, it wraps all the #defines with #ifndefs. This script should be run
1663        before "make dist".
1664    
1665    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1666        with Unicode property support.
1667    
1668        (a) For a maximizing quantifier, if the two different cases of the
1669            character were of different lengths in their UTF-8 codings (there are
1670            some cases like this - I found 11), and the matching function had to
1671            back up over a mixture of the two cases, it incorrectly assumed they
1672            were both the same length.
1673    
1674        (b) When PCRE was configured to use the heap rather than the stack for
1675            recursion during matching, it was not correctly preserving the data for
1676            the other case of a UTF-8 character when checking ahead for a match
1677            while processing a minimizing repeat. If the check also involved
1678            matching a wide character, but failed, corruption could cause an
1679            erroneous result when trying to check for a repeat of the original
1680            character.
1681    
1682    13. Some tidying changes to the testing mechanism:
1683    
1684        (a) The RunTest script now detects the internal link size and whether there
1685            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1686            values substituted by "configure". (The RunGrepTest script already did
1687            this for UTF-8.) The configure.ac script no longer substitutes the
1688            relevant variables.
1689    
1690        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1691            with length and offset values. This means that the output is different
1692            for different internal link sizes. Test 2 is skipped for link sizes
1693            other than 2 because of this, bypassing the problem. Unfortunately,
1694            there was also a test in test 3 (the locale tests) that used /B and
1695            failed for link sizes other than 2. Rather than cut the whole test out,
1696            I have added a new /Z option to pcretest that replaces the length and
1697            offset values with spaces. This is now used to make test 3 independent
1698            of link size. (Test 2 will be tidied up later.)
1699    
1700    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1701        segmentation fault instead of returning the appropriate error message.
1702    
1703    15. In multiline mode when the newline sequence was set to "any", the pattern
1704        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1705        This doesn't seem right; it now treats the CRLF combination as the line
1706        ending, and so does not match in that case. It's only a pattern such as ^$
1707        that would hit this one: something like ^ABC$ would have failed after \r
1708        and then tried again after \r\n.
1709    
1710    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1711        in an attempt to make files that differ only in their line terminators
1712        compare equal. This works on Linux.
1713    
1714    17. Under certain error circumstances pcregrep might try to free random memory
1715        as it exited. This is now fixed, thanks to valgrind.
1716    
1717    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1718        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1719        was because its rules for how to advance for /g after matching an empty
1720        string at the end of a line did not allow for this case. They now check for
1721        it specially.
1722    
1723    20. pcretest is supposed to handle patterns and data of any length, by
1724        extending its buffers when necessary. It was getting this wrong when the
1725        buffer for a data line had to be extended.
1726    
1727    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1728        CRLF as a newline sequence.
1729    
1730    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1731        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1732        I have nevertheless tidied it up.
1733    
1734    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1735    
1736    24. Added a man page for pcre-config.
1737    
1738    
1739    Version 7.0 19-Dec-06
1740    ---------------------
1741    
1742     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1743        moving to gcc 4.1.1.
1744    
1745     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1746        sys/time.h, which is documented as needed for this function. It doesn't
1747        seem to matter on Linux, but it showed up on some releases of OS X.
1748    
1749     3. It seems that there are systems where bytes whose values are greater than
1750        127 match isprint() in the "C" locale. The "C" locale should be the
1751        default when a C program starts up. In most systems, only ASCII printing
1752        characters match isprint(). This difference caused the output from pcretest
1753        to vary, making some of the tests fail. I have changed pcretest so that:
1754    
1755        (a) When it is outputting text in the compiled version of a pattern, bytes
1756            other than 32-126 are always shown as hex escapes.
1757    
1758        (b) When it is outputting text that is a matched part of a subject string,
1759            it does the same, unless a different locale has been set for the match
1760            (using the /L modifier). In this case, it uses isprint() to decide.
1761    
1762     4. Fixed a major bug that caused incorrect computation of the amount of memory
1763        required for a compiled pattern when options that changed within the
1764        pattern affected the logic of the preliminary scan that determines the
1765        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1766        that the computed length was too small. The symptoms of this bug were
1767        either the PCRE error "internal error: code overflow" from pcre_compile(),
1768        or a glibc crash with a message such as "pcretest: free(): invalid next
1769        size (fast)". Examples of patterns that provoked this bug (shown in
1770        pcretest format) are:
1771    
1772          /(?-x: )/x
1773          /(?x)(?-x: \s*#\s*)/
1774          /((?i)[\x{c0}])/8
1775          /(?i:[\x{c0}])/8
1776    
1777        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1778        is now done differently.
1779    
1780     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1781        wrapper classes; (b) implement a new function in the C++ scanner that is
1782        more efficient than the old way of doing things because it avoids levels of
1783        recursion in the regex matching; (c) add a paragraph to the documentation
1784        for the FullMatch() function.
1785    
1786     6. The escape sequence \n was being treated as whatever was defined as
1787        "newline". Not only was this contrary to the documentation, which states
1788        that \n is character 10 (hex 0A), but it also went horribly wrong when
1789        "newline" was defined as CRLF. This has been fixed.
1790    
1791     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1792        was being set to -1 for the "end of line" case (supposedly a value that no
1793        character can have). Though this value is never used (the check for end of
1794        line is "zero bytes in current character"), it caused compiler complaints.
1795        I've changed it to 0xffffffff.
1796    
1797     8. In pcre_version.c, the version string was being built by a sequence of
1798        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1799        string (as it is for production releases) called a macro with an empty
1800        argument. The C standard says the result of this is undefined. The gcc
1801        compiler treats it as an empty string (which was what was wanted) but it is
1802        reported that Visual C gives an error. The source has been hacked around to
1803        avoid this problem.
1804    
1805     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1806        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1807        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1808        of them did).
1809    
1810    10. Originally, pcretest opened its input and output without "b"; then I was
1811        told that "b" was needed in some environments, so it was added for release
1812        5.0 to both the input and output. (It makes no difference on Unix-like
1813        systems.) Later I was told that it is wrong for the input on Windows. I've
1814        now abstracted the modes into two macros, to make it easier to fiddle with
1815        them, and removed "b" from the input mode under Windows.
1816    
1817    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1818    
1819    12. Added -help and --help to pcretest as an official way of being reminded
1820        of the options.
1821    
1822    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1823        and pcrecpp.cc because they annoy compilers at high warning levels.
1824    
1825    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1826    
1827    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1828        scripts are not C programs :-) and which was not noticed because it works
1829        on Linux.
1830    
1831    16. pcretest is supposed to handle any length of pattern and data line (as one
1832        line or as a continued sequence of lines) by extending its input buffer if
1833        necessary. This feature was broken for very long pattern lines, leading to
1834        a string of junk being passed to pcre_compile() if the pattern was longer
1835        than about 50K.
1836    
1837    17. I have done a major re-factoring of the way pcre_compile() computes the
1838        amount of memory needed for a compiled pattern. Previously, there was code
1839        that made a preliminary scan of the pattern in order to do this. That was
1840        OK when PCRE was new, but as the facilities have expanded, it has become
1841        harder and harder to keep it in step with the real compile phase, and there
1842        have been a number of bugs (see for example, 4 above). I have now found a
1843        cunning way of running the real compile function in a "fake" mode that
1844        enables it to compute how much memory it would need, while actually only
1845        ever using a few hundred bytes of working memory and without too many
1846        tests of the mode. This should make future maintenance and development
1847        easier. A side effect of this work is that the limit of 200 on the nesting
1848        depth of parentheses has been removed (though this was never a serious
1849        limitation, I suspect). However, there is a downside: pcre_compile() now
1850        runs more slowly than before (30% or more, depending on the pattern). I
1851        hope this isn't a big issue. There is no effect on runtime performance.
1852    
1853    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1854        newline (only possible for the last line of a file) and it was a
1855        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1856    
1857    19. Added additional timing features to pcretest. (1) The -tm option now times
1858        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1859        separate command line item, by a number that specifies the number of
1860        repeats to use when timing. The default is 50000; this gives better
1861        precision, but takes uncomfortably long for very large patterns.
1862    
1863    20. Extended pcre_study() to be more clever in cases where a branch of a
1864        subpattern has no definite first character. For example, (a*|b*)[cd] would
1865        previously give no result from pcre_study(). Now it recognizes that the
1866        first character must be a, b, c, or d.
1867    
1868    21. There was an incorrect error "recursive call could loop indefinitely" if
1869        a subpattern (or the entire pattern) that was being tested for matching an
1870        empty string contained only one non-empty item after a nested subpattern.
1871        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1872        incorrectly, because the \d was being skipped in the check.
1873    
1874    22. The pcretest program now has a new pattern option /B and a command line
1875        option -b, which is equivalent to adding /B to every pattern. This causes
1876        it to show the compiled bytecode, without the additional information that
1877        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1878        is the same as /B/I).
1879    
1880    23. A new optimization is now able automatically to treat some sequences such
1881        as a*b as a*+b. More specifically, if something simple (such as a character
1882        or a simple class like \d) has an unlimited quantifier, and is followed by
1883        something that cannot possibly match the quantified thing, the quantifier
1884        is automatically "possessified".
1885    
1886    24. A recursive reference to a subpattern whose number was greater than 39
1887        went wrong under certain circumstances in UTF-8 mode. This bug could also
1888        have affected the operation of pcre_study().
1889    
1890    25. Realized that a little bit of performance could be had by replacing
1891        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1892    
1893    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1894    
1895    27. Possessive quantifiers such as a++ were previously implemented by turning
1896        them into atomic groups such as ($>a+). Now they have their own opcodes,
1897        which improves performance. This includes the automatically created ones
1898        from 23 above.
1899    
1900    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1901        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1902        the first matched character to be a colon. This applied both to named and
1903        numbered groups.
1904    
1905    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1906    
1907    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1908        building PCRE on Windows easier, so I have included it in the distribution.
1909    
1910    31. There is now a check in pcretest against a ridiculously large number being
1911        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1912        loop, the loop is abandoned.
1913    
1914    32. Forward references to subpatterns in conditions such as (?(2)...) where
1915        subpattern 2 is defined later cause pcre_compile() to search forwards in
1916        the pattern for the relevant set of parentheses. This search went wrong
1917        when there were unescaped parentheses in a character class, parentheses
1918        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1919    
1920    33. "Subroutine" calls and backreferences were previously restricted to
1921        referencing subpatterns earlier in the regex. This restriction has now
1922        been removed.
1923    
1924    34. Added a number of extra features that are going to be in Perl 5.10. On the
1925        whole, these are just syntactic alternatives for features that PCRE had
1926        previously implemented using the Python syntax or my own invention. The
1927        other formats are all retained for compatibility.
1928    
1929        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1930            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1931            also .NET compatible.
1932    
1933        (b) A recursion or subroutine call to a named group can now be defined as
1934            (?&name) as well as (?P>name).
1935    
1936        (c) A backreference to a named group can now be defined as \k<name> or
1937            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1938            5.10, are also .NET compatible.
1939    
1940        (d) A conditional reference to a named group can now use the syntax
1941            (?(<name>) or (?('name') as well as (?(name).
1942    
1943        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1944            groups (named and numbered) that are never evaluated inline, but can be
1945            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1946            is always false. There may be only one alternative in such a group.
1947    
1948        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1949            as the simple (?(R). The condition is true only if the most recent
1950            recursion is that of the given number or name. It does not search out
1951            through the entire recursion stack.
1952    
1953        (g) The escape \gN or \g{N} has been added, where N is a positive or
1954            negative number, specifying an absolute or relative reference.
1955    
1956    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1957        some "unreachable code" warnings.
1958    
1959    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1960        things, this adds five new scripts.
1961    
1962    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1963        There were also incompatibilities regarding the handling of \Q..\E inside
1964        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1965        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1966    
1967    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1968        matches an empty string, and forcibly breaks the loop. There were bugs in
1969        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1970        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1971        separate and independent bugs (that affected different cases) have been
1972        fixed.
1973    
1974    39. Refactored the code to abolish the use of different opcodes for small
1975        capturing bracket numbers. This is a tidy that I avoided doing when I
1976        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1977        The new approach is not only tidier, it makes it possible to reduce the
1978        memory needed to fix the previous bug (38).
1979    
1980    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1981        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1982        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1983        mode.
1984    
1985    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1986        report.
1987    
1988    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1989        copy construction and assignment in the C++ wrapper.
1990    
1991    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1992        couple of bugs that could have given wrong results in the "--newline=crlf"
1993        case.
1994    
1995    44. Added a number of casts and did some reorganization of signed/unsigned int
1996        variables following suggestions from Dair Grant. Also renamed the variable
1997        "this" as "item" because it is a C++ keyword.
1998    
1999    45. Arranged for dftables to add
2000    
2001          #include "pcre_internal.h"
2002    
2003        to pcre_chartables.c because without it, gcc 4.x may remove the array
2004        definition from the final binary if PCRE is built into a static library and
2005        dead code stripping is activated.
2006    
2007    46. For an unanchored pattern, if a match attempt fails at the start of a
2008        newline sequence, and the newline setting is CRLF or ANY, and the next two
2009        characters are CRLF, advance by two characters instead of one.
2010    
2011    
2012    Version 6.7 04-Jul-06
2013    ---------------------
2014    
2015     1. In order to handle tests when input lines are enormously long, pcretest has
2016        been re-factored so that it automatically extends its buffers when
2017        necessary. The code is crude, but this _is_ just a test program. The
2018        default size has been increased from 32K to 50K.
2019    
2020     2. The code in pcre_study() was using the value of the re argument before
2021        testing it for NULL. (Of course, in any sensible call of the function, it
2022        won't be NULL.)
2023    
2024     3. The memmove() emulation function in pcre_internal.h, which is used on
2025        systems that lack both memmove() and bcopy() - that is, hardly ever -
2026        was missing a "static" storage class specifier.
2027    
2028     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2029        containing an extended class (one that cannot be represented by a bitmap
2030        because it contains high-valued characters or Unicode property items, e.g.
2031        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2032        pattern, but PCRE should not loop if you do not (it no longer does).
2033        [Detail: two cases were found: (a) a repeated subpattern containing an
2034        extended class; (b) a recursive reference to a subpattern that followed a
2035        previous extended class. It wasn't skipping over the extended class
2036        correctly when UTF-8 mode was not set.]
2037    
2038     5. A negated single-character class was not being recognized as fixed-length
2039        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2040        compile error "lookbehind assertion is not fixed length".
2041    
2042     6. The RunPerlTest auxiliary script was showing an unexpected difference
2043        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2044        write a Perl script that can interpret lines of an input file either as
2045        byte characters or as UTF-8, which is what "perltest" was being required to
2046        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2047        can't do is switch easily at run time between having the "use utf8;" pragma
2048        or not. In the end, I fudged it by using the RunPerlTest script to insert
2049        "use utf8;" explicitly for the UTF-8 tests.
2050    
2051     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2052        the end of the subject string, contrary to the documentation and to what
2053        Perl does. This was true of both matching functions. Now it matches only at
2054        the start of the subject and immediately after *internal* newlines.
2055    
2056     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2057        a pointer to an int instead of a pointer to an unsigned long int. This
2058        caused problems on 64-bit systems.
2059    
2060     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2061        instance of the 'standard' template library not being so standard".
2062    
2063    10. There was no check on the number of named subpatterns nor the maximum
2064        length of a subpattern name. The product of these values is used to compute
2065        the size of the memory block for a compiled pattern. By supplying a very
2066        long subpattern name and a large number of named subpatterns, the size
2067        computation could be caused to overflow. This is now prevented by limiting
2068        the length of names to 32 characters, and the number of named subpatterns
2069        to 10,000.
2070    
2071    11. Subpatterns that are repeated with specific counts have to be replicated in
2072        the compiled pattern. The size of memory for this was computed from the
2073        length of the subpattern and the repeat count. The latter is limited to
2074        65535, but there was no limit on the former, meaning that integer overflow
2075        could in principle occur. The compiled length of a repeated subpattern is
2076        now limited to 30,000 bytes in order to prevent this.
2077    
2078    12. Added the optional facility to have named substrings with the same name.
2079    
2080    13. Added the ability to use a named substring as a condition, using the
2081        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2082        are numbers (not recommended). Forward references are permitted.
2083    
2084    14. Added forward references in named backreferences (if you see what I mean).
2085    
2086    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2087        pattern could run off the end of the subject. For example, the pattern
2088        "(?s)(.{1,5})"8 did this with the subject "ab".
2089    
2090    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2091        PCRE_CASELESS was set when matching characters that were quantified with ?
2092        or *.
2093    
2094    17. A character class other than a single negated character that had a minimum
2095        but no maximum quantifier - for example [ab]{6,} - was not handled
2096        correctly by pce_dfa_exec(). It would match only one character.
2097    
2098    18. A valid (though odd) pattern that looked like a POSIX character
2099        class but used an invalid character after [ (for example [[,abc,]]) caused
2100        pcre_compile() to give the error "Failed: internal error: code overflow" or
2101        in some cases to crash with a glibc free() error. This could even happen if
2102        the pattern terminated after [[ but there just happened to be a sequence of
2103        letters, a binary zero, and a closing ] in the memory that followed.
2104    
2105    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2106        over the years. Originally (before any Unicode support), just the bottom 8
2107        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2108        output from "man perlunicode" includes this:
2109    
2110          The regular expression compiler produces polymorphic opcodes.  That
2111          is, the pattern adapts to the data and automatically switches to
2112          the Unicode character scheme when presented with Unicode data--or
2113          instead uses a traditional byte scheme when presented with byte
2114          data.
2115    
2116        Sadly, a wide octal escape does not cause a switch, and in a string with
2117        no other multibyte characters, these octal escapes are treated as before.
2118        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2119        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2120        Unicode string.
2121    
2122        I have not perpetrated such confusion in PCRE. Up till now, it took just
2123        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2124        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2125        translate to the appropriate multibyte character.
2126    
2127    29. Applied some refactoring to reduce the number of warnings from Microsoft
2128        and Borland compilers. This has included removing the fudge introduced
2129        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2130        a warning about an unused variable.
2131    
2132    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2133        characters since release 4.0, because Perl (from release 5.004) does not.
2134        [Or at least, is documented not to: some releases seem to be in conflict
2135        with the documentation.] However, when a pattern was studied with
2136        pcre_study() and all its branches started with \s, PCRE still included VT
2137        as a possible starting character. Of course, this did no harm; it just
2138        caused an unnecessary match attempt.
2139    
2140    22. Removed a now-redundant internal flag bit that recorded the fact that case
2141        dependency changed within the pattern. This was once needed for "required
2142        byte" processing, but is no longer used. This recovers a now-scarce options
2143        bit. Also moved the least significant internal flag bit to the most-
2144        significant bit of the word, which was not previously used (hangover from
2145        the days when it was an int rather than a uint) to free up another bit for
2146        the future.
2147    
2148    23. Added support for CRLF line endings as well as CR and LF. As well as the
2149        default being selectable at build time, it can now be changed at runtime
2150        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2151        specify that it is scanning data with non-default line endings.
2152    
2153    24. Changed the definition of CXXLINK to make it agree with the definition of
2154        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2155    
2156    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2157        recursions. This makes a big different to stack usage for some patterns.
2158    
2159    26. If a subpattern containing a named recursion or subroutine reference such
2160        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2161        the space required for the compiled pattern went wrong and gave too small a
2162        value. Depending on the environment, this could lead to "Failed: internal
2163        error: code overflow at offset 49" or "glibc detected double free or
2164        corruption" errors.
2165    
2166    27. Applied patches from Google (a) to support the new newline modes and (b) to
2167        advance over multibyte UTF-8 characters in GlobalReplace.
2168    
2169    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2170        difference for some implementation of PCRE in some Windows version.
2171    
2172    29. Added some extra testing facilities to pcretest:
2173    
2174        \q<number>   in a data line sets the "match limit" value
2175        \Q<number>   in a data line sets the "match recursion limt" value
2176        -S <number>  sets the stack size, where <number> is in megabytes
2177    
2178        The -S option isn't available for Windows.
2179    
2180    
2181    Version 6.6 06-Feb-06
2182    ---------------------
2183    
2184     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2185        in pcreposix.h. I have copied the definition from pcre.h.
2186    
2187     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2188        because pcre.h is no longer a built file.
2189    
2190     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2191        not normally included in the compiled code.
2192    
2193    
2194    Version 6.5 01-Feb-06
2195    ---------------------
2196    
2197     1. When using the partial match feature with pcre_dfa_exec(), it was not
2198        anchoring the second and subsequent partial matches at the new starting
2199        point. This could lead to incorrect results. For example, with the pattern
2200        /1234/, partially matching against "123" and then "a4" gave a match.
2201    
2202     2. Changes to pcregrep:
2203    
2204        (a) All non-match returns from pcre_exec() were being treated as failures
2205            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2206            error message is output. Some extra information is given for the
2207            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2208            probably the only errors that are likely to be caused by users (by
2209            specifying a regex that has nested indefinite repeats, for instance).
2210            If there are more than 20 of these errors, pcregrep is abandoned.
2211    
2212        (b) A binary zero was treated as data while matching, but terminated the
2213            output line if it was written out. This has been fixed: binary zeroes
2214            are now no different to any other data bytes.
2215    
2216        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2217            used to set a locale for matching. The --locale=xxxx long option has
2218            been added (no short equivalent) to specify a locale explicitly on the
2219            pcregrep command, overriding the environment variables.
2220    
2221        (d) When -B was used with -n, some line numbers in the output were one less
2222            than they should have been.
2223    
2224        (e) Added the -o (--only-matching) option.
2225    
2226        (f) If -A or -C was used with -c (count only), some lines of context were
2227            accidentally printed for the final match.
2228    
2229        (g) Added the -H (--with-filename) option.
2230    
2231        (h) The combination of options -rh failed to suppress file names for files
2232            that were found from directory arguments.
2233    
2234        (i) Added the -D (--devices) and -d (--directories) options.
2235    
2236        (j) Added the -F (--fixed-strings) option.
2237    
2238        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2239    
2240        (l) Added the --colo(u)r option.
2241    
2242        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2243            is not present by default.
2244    
2245     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2246        items such as (?R) or (?1), when the recursion could match a number of
2247        alternatives. If it matched one of the alternatives, but subsequently,
2248        outside the recursion, there was a failure, the code tried to back up into
2249        the recursion. However, because of the way PCRE is implemented, this is not
2250        possible, and the result was an incorrect result from the match.
2251    
2252        In order to prevent this happening, the specification of recursion has
2253        been changed so that all such subpatterns are automatically treated as
2254        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2255    
2256     4. I had overlooked the fact that, in some locales, there are characters for
2257        which isalpha() is true but neither isupper() nor islower() are true. In
2258        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2259        and ordfeminine) are like this. This affected the treatment of \w and \W
2260        when they appeared in character classes, but not when they appeared outside
2261        a character class. The bit map for "word" characters is now created
2262        separately from the results of isalnum() instead of just taking it from the
2263        upper, lower, and digit maps. (Plus the underscore character, of course.)
2264    
2265     5. The above bug also affected the handling of POSIX character classes such as
2266        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2267        permanent tables. Instead, the bit maps for such a class were previously
2268        created as the appropriate unions of the upper, lower, and digit bitmaps.
2269        Now they are created by subtraction from the [[:word:]] class, which has
2270        its own bitmap.
2271    
2272     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2273        It is created by subtracting the vertical space characters (\x09, \x0a,
2274        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2275        subtraction was done in the overall bitmap for a character class, meaning
2276        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2277        be recognized. This bug has been fixed.
2278    
2279     7. Patches from the folks at Google:
2280    
2281          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2282          real life, but is still worth protecting against".
2283    
2284          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2285          regular expressions".
2286    
2287          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2288          have it.
2289    
2290          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2291          "configure" and the latter not, in order to fix a problem somebody had
2292          with compiling the Arg class on HP-UX.
2293    
2294          (e) Improve the error-handling of the C++ wrapper a little bit.
2295    
2296          (f) New tests for checking recursion limiting.
2297    
2298     8. The pcre_memmove() function, which is used only if the environment does not
2299        have a standard memmove() function (and is therefore rarely compiled),
2300        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2301        returning a result (though PCRE never actually uses the result).
2302    
2303     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2304        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2305        returned instead of calling malloc() with an overflowing number that would
2306        most likely cause subsequent chaos.
2307    
2308    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2309    
2310    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2311        with this option is matched, the nmatch and pmatch options of regexec() are
2312        ignored.
2313    
2314    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2315        provided in case anyone wants to the the POSIX interface with UTF-8
2316        strings.
2317    
2318    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2319        C++ linking (needed for some HP-UX environments).
2320    
2321    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2322        (unused parameter) and in the pcre_printint() function (omitted "default"
2323        switch label when the default is to do nothing).
2324    
2325    15. Added some code to make it possible, when PCRE is compiled as a C++
2326        library, to replace subject pointers for pcre_exec() with a smart pointer
2327        class, thus making it possible to process discontinuous strings.
2328    
2329    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2330        much the same function. They were added by different people who were trying
2331        to make PCRE easy to compile on non-Unix systems. It has been suggested
2332        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2333        for compiling on Windows systems. I have therefore replaced it with
2334        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2335        defaults to "extern" for C or "extern C" for C++, which works fine on
2336        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2337        SCOPE with something explicit in config.h. In addition:
2338    
2339        (a) pcreposix.h still had just "extern" instead of either of these macros;
2340            I have replaced it with PCRE_DATA_SCOPE.
2341    
2342        (b) Functions such as _pcre_xclass(), which are internal to the library,
2343            but external in the C sense, all had PCRE_EXPORT in their definitions.
2344            This is apparently wrong for the Windows case, so I have removed it.
2345            (It makes no difference on Unix-like systems.)
2346    
2347    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2348        of recursive calls to match(). This is different to MATCH_LIMIT because
2349        that limits the total number of calls to match(), not all of which increase
2350        the depth of recursion. Limiting the recursion depth limits the amount of
2351        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2352        when PCRE is compiled, and changed at run time. A patch from Google adds
2353        this functionality to the C++ interface.
2354    
2355    18. Changes to the handling of Unicode character properties:
2356    
2357        (a) Updated the table to Unicode 4.1.0.
2358    
2359        (b) Recognize characters that are not in the table as "Cn" (undefined).
2360    
2361        (c) I revised the way the table is implemented to a much improved format
2362            which includes recognition of ranges. It now supports the ranges that
2363            are defined in UnicodeData.txt, and it also amalgamates other
2364            characters into ranges. This has reduced the number of entries in the
2365            table from around 16,000 to around 3,000, thus reducing its size
2366            considerably. I realized I did not need to use a tree structure after
2367            all - a binary chop search is just as efficient. Having reduced the
2368            number of entries, I extended their size from 6 bytes to 8 bytes to
2369            allow for more data.
2370    
2371        (d) Added support for Unicode script names via properties such as \p{Han}.
2372    
2373    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2374        matching that character.
2375    
2376    20. When matching a repeated Unicode property with a minimum greater than zero,
2377        (for example \pL{2,}), PCRE could look past the end of the subject if it
2378        reached it while seeking the minimum number of characters. This could
2379        happen only if some of the characters were more than one byte long, because
2380        there is a check for at least the minimum number of bytes.
2381    
2382    21. Refactored the implementation of \p and \P so as to be more general, to
2383        allow for more different types of property in future. This has changed the
2384        compiled form incompatibly. Anybody with saved compiled patterns that use
2385        \p or \P will have to recompile them.
2386    
2387    22. Added "Any" and "L&" to the supported property types.
2388    
2389    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2390        but give a compile time error if the value is greater than 0xff.
2391    
2392    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2393        accidentally not being installed or uninstalled.
2394    
2395    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2396        made were to insert the current release number. This seemed silly, because
2397        it made things harder for people building PCRE on systems that don't run
2398        "configure". I have turned pcre.h into a distributed file, no longer built
2399        by "configure", with the version identification directly included. There is
2400        no longer a pcre.h.in file.
2401    
2402        However, this change necessitated a change to the pcre-config script as
2403        well. It is built from pcre-config.in, and one of the substitutions was the
2404        release number. I have updated configure.ac so that ./configure now finds
2405        the release number by grepping pcre.h.
2406    
2407    26. Added the ability to run the tests under valgrind.
2408    
2409    
2410    Version 6.4 05-Sep-05
2411    ---------------------
2412    
2413     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2414        "--" to be printed when multiple files were scanned, even when none of the
2415        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2416        consider it to be a bug, and have restored the previous behaviour.
2417    
2418     2. A couple of code tidies to get rid of compiler warnings.
2419    
2420     3. The pcretest program used to cheat by referring to symbols in the library
2421        whose names begin with _pcre_. These are internal symbols that are not
2422        really supposed to be visible externally, and in some environments it is
2423        possible to suppress them. The cheating is now confined to including
2424        certain files from the library's source, which is a bit cleaner.
2425    
2426     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2427        file's purpose clearer.
2428    
2429     5. Reorganized pcre_ucp_findchar().
2430    
2431    
2432    Version 6.3 15-Aug-05
2433    ---------------------
2434    
2435     1. The file libpcre.pc.in did not have general read permission in the tarball.
2436    
2437     2. There were some problems when building without C++ support:
2438    
2439        (a) If C++ support was not built, "make install" and "make test" still
2440            tried to test it.
2441    
2442        (b) There were problems when the value of CXX was explicitly set. Some
2443            changes have been made to try to fix these, and ...
2444    
2445        (c) --disable-cpp can now be used to explicitly disable C++ support.
2446    
2447        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2448            backslash in a target when C++ was disabled. This confuses some
2449            versions of "make", apparently. Using an intermediate variable solves
2450            this. (Same for CPP_LOBJ.)
2451    
2452     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2453        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2454        necessary on certain architectures.
2455    
2456     4. Added a setting of -export-symbols-regex to the link command to remove
2457        those symbols that are exported in the C sense, but actually are local
2458        within the library, and not documented. Their names all begin with
2459        "_pcre_". This is not a perfect job, because (a) we have to except some
2460        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2461        available (and never for static libraries). I have made a note to try to
2462        find a way round (a) in the future.
2463    
2464    
2465    Version 6.2 01-Aug-05
2466    ---------------------
2467    
2468     1. There was no test for integer overflow of quantifier values. A construction
2469        such as {1111111111111111} would give undefined results. What is worse, if
2470        a minimum quantifier for a parenthesized subpattern overflowed and became
2471        negative, the calculation of the memory size went wrong. This could have
2472        led to memory overwriting.
2473    
2474     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2475    
2476     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2477        operating environments where this matters.
2478    
2479     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2480        PCRE options from within the C++ wrapper.
2481    
2482     5. Named capturing subpatterns were not being correctly counted when a pattern
2483        was compiled. This caused two problems: (a) If there were more than 100
2484        such subpatterns, the calculation of the memory needed for the whole
2485        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2486        back references of the form \12, where the number was greater than 9, were
2487        not recognized as back references, even though there were sufficient
2488        previous subpatterns.
2489    
2490     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2491        versions of gcc, e.g. 2.95.4.
2492    
2493    
2494    Version 6.1 21-Jun-05
2495    ---------------------
2496    
2497     1. There was one reference to the variable "posix" in pcretest.c that was not
2498        surrounded by "#if !defined NOPOSIX".
2499    
2500     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2501        the cross-check on the old pcre_info() function, for the benefit of the
2502        cut-down version of PCRE that is currently imported into Exim.
2503    
2504     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2505        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2506        patterns that start (?i) but I don't think that matters. The use of (?i) is
2507        just an example; this all applies to the other options as well.
2508    
2509     4. Since libtool seems to echo the compile commands it is issuing, the output
2510        from "make" can be reduced a bit by putting "@" in front of each libtool
2511        compile command.
2512    
2513     5. Patch from the folks at Google for configure.in to be a bit more thorough
2514        in checking for a suitable C++ installation before trying to compile the
2515        C++ stuff. This should fix a reported problem when a compiler was present,
2516        but no suitable headers.
2517    
2518     6. The man pages all had just "PCRE" as their title. I have changed them to
2519        be the relevant file name. I have also arranged that these names are
2520        retained in the file doc/pcre.txt, which is a concatenation in text format
2521        of all the man pages except the little individual ones for each function.
2522    
2523     7. The NON-UNIX-USE file had not been updated for the different set of source
2524        files that come with release 6. I also added a few comments about the C++
2525        wrapper.
2526    
2527    
2528    Version 6.0 07-Jun-05
2529    ---------------------
2530    
2531     1. Some minor internal re-organization to help with my DFA experiments.
2532    
2533     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2534        didn't matter for the library itself when fully configured, but did matter
2535        when compiling without UCP support, or within Exim, where the ucp files are
2536        not imported.
2537    
2538     3. Refactoring of the library code to split up the various functions into
2539        different source modules. The addition of the new DFA matching code (see
2540        below) to a single monolithic source would have made it really too
2541        unwieldy, quite apart from causing all the code to be include in a
2542        statically linked application, when only some functions are used. This is
2543        relevant even without the DFA addition now that patterns can be compiled in
2544        one application and matched in another.
2545    
2546        The downside of splitting up is that there have to be some external
2547        functions and data tables that are used internally in different modules of
2548        the library but which are not part of the API. These have all had their
2549        names changed to start with "_pcre_" so that they are unlikely to clash
2550        with other external names.
2551    
2552     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2553        a different (DFA) algorithm. Although it is slower than the original
2554        function, it does have some advantages for certain types of matching
2555        problem.
2556    
2557     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2558        including restarting after a partial match.
2559    
2560     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2561        defined when compiling for Windows was sent to me. I have put it into the
2562        code, though I have no means of testing or verifying it.
2563    
2564     7. Added the pcre_refcount() auxiliary function.
2565    
2566     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2567        match before or at the first newline in the subject string. In pcretest,
2568        the /f option on a pattern can be used to set this.
2569    
2570     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2571        would behave wrongly. This has been present in PCRE since release 4.0.
2572    
2573    10. A number of changes to the pcregrep command:
2574    
2575        (a) Refactored how -x works; insert ^(...)$ instead of setting
2576            PCRE_ANCHORED and checking the length, in preparation for adding
2577            something similar for -w.
2578    
2579        (b) Added the -w (match as a word) option.
2580    
2581        (c) Refactored the way lines are read and buffered so as to have more
2582            than one at a time available.
2583    
2584        (d) Implemented a pcregrep test script.
2585    
2586        (e) Added the -M (multiline match) option. This allows patterns to match
2587            over several lines of the subject. The buffering ensures that at least
2588            8K, or the rest of the document (whichever is the shorter) is available
2589            for matching (and similarly the previous 8K for lookbehind assertions).
2590    
2591        (f) Changed the --help output so that it now says
2592    
2593              -w, --word-regex(p)
2594    
2595            instead of two lines, one with "regex" and the other with "regexp"
2596            because that confused at least one person since the short forms are the
2597            same. (This required a bit of code, as the output is generated
2598            automatically from a table. It wasn't just a text change.)
2599    
2600        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2601            option but starts with a hyphen. Could be a pattern or a path name
2602            starting with a hyphen, for instance.
2603    
2604        (h) "-" can be given as a file name to represent stdin.
2605    
2606        (i) When file names are being printed, "(standard input)" is used for
2607            the standard input, for compatibility with GNU grep. Previously
2608            "<stdin>" was used.
2609    
2610        (j) The option --label=xxx can be used to supply a name to be used for
2611            stdin when file names are being printed. There is no short form.
2612    
2613        (k) Re-factored the options decoding logic because we are going to add
2614            two more options that take data. Such options can now be given in four
2615            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2616    
2617        (l) Added the -A, -B, and -C options for requesting that lines of context
2618            around matches be printed.
2619    
2620        (m) Added the -L option to print the names of files that do not contain
2621            any matching lines, that is, the complement of -l.
2622    
2623        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2624            continue to scan other files.
2625    
2626        (o) The -s option was incorrectly implemented. For compatibility with other
2627            greps, it now suppresses the error message for a non-existent or non-
2628            accessible file (but not the return code). There is a new option called
2629            -q that suppresses the output of matching lines, which was what -s was
2630            previously doing.
2631    
2632        (p) Added --include and --exclude options to specify files for inclusion
2633            and exclusion when recursing.
2634    
2635    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2636        Hopefully, it now does.
2637    
2638    12. Missing cast in pcre_study().
2639    
2640    13. Added an "uninstall" target to the makefile.
2641    
2642    14. Replaced "extern" in the function prototypes in Makefile.in with
2643        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2644        world, but is set differently for Windows.
2645    
2646    15. Added a second compiling function called pcre_compile2(). The only
2647        difference is that it has an extra argument, which is a pointer to an
2648        integer error code. When there is a compile-time failure, this is set
2649        non-zero, in addition to the error test pointer being set to point to an
2650        error message. The new argument may be NULL if no error number is required
2651        (but then you may as well call pcre_compile(), which is now just a
2652        wrapper). This facility is provided because some applications need a
2653        numeric error indication, but it has also enabled me to tidy up the way
2654        compile-time errors are handled in the POSIX wrapper.
2655    
2656    16. Added VPATH=.libs to the makefile; this should help when building with one
2657        prefix path and installing with another. (Or so I'm told by someone who
2658        knows more about this stuff than I do.)
2659    
2660    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2661        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2662        match everything, including newlines. This is not POSIX-compatible, but
2663        somebody wanted the feature. From pcretest it can be activated by using
2664        both the P and the s flags.
2665    
2666    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2667    
2668    19. libpcre.pc was being incorrectly installed as executable.
2669    
2670    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2671        it now also looks for '\r' so that it will work unmodified on Windows.
2672    
2673    21. Added Google's contributed C++ wrapper to the distribution.
2674    
2675    22. Added some untidy missing memory free() calls in pcretest, to keep
2676        Electric Fence happy when testing.
2677    
2678    
2679    
2680    Version 5.0 13-Sep-04
2681    ---------------------
2682    
2683     1. Internal change: literal characters are no longer packed up into items
2684        containing multiple characters in a single byte-string. Each character
2685        is now matched using a separate opcode. However, there may be more than one
2686        byte in the character in UTF-8 mode.
2687    
2688     2. The pcre_callout_block structure has two new fields: pattern_position and
2689        next_item_length. These contain the offset in the pattern to the next match
2690        item, and its length, respectively.
2691    
2692     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2693        insertion of callouts before each pattern item. Added the /C option to
2694        pcretest to make use of this.
2695    
2696     4. On the advice of a Windows user, the lines
2697    
2698          #if defined(_WIN32) || defined(WIN32)
2699          _setmode( _fileno( stdout ), 0x8000 );
2700          #endif  /* defined(_WIN32) || defined(WIN32) */
2701    
2702        have been added to the source of pcretest. This apparently does useful
2703        magic in relation to line terminators.
2704    
2705     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2706        for the benefit of those environments where the "b" makes a difference.
2707    
2708     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2709        to know about it. I have put a hack into configure.in that adds in code
2710        to set GCC=yes if CC=icc. This seems to end up at a point in the
2711        generated configure script that is early enough to affect the setting of
2712        compiler options, which is what is needed, but I have no means of testing
2713        whether it really works. (The user who reported this had patched the
2714        generated configure script, which of course I cannot do.)
2715    
2716        LATER: After change 22 below (new libtool files), the configure script
2717        seems to know about icc (and also ecc). Therefore, I have commented out
2718        this hack in configure.in.
2719    
2720     7. Added support for pkg-config (2 patches were sent in).
2721    
2722     8. Negated POSIX character classes that used a combination of internal tables
2723        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2724        [[:^ascii]]. Typically, they would match almost any characters. The other
2725        POSIX classes were not broken in this way.
2726    
2727     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2728        to find the match, as PCRE was deluded into thinking that the match had to
2729        start at the start point or following a newline. The same bug applied to
2730        patterns with negative forward assertions or any backward assertions
2731        preceding ".*" at the start, unless the pattern required a fixed first
2732        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2733    
2734    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2735        starting at the last subject character, bytes beyond the end of the subject
2736        string were read.
2737    
2738    11. Renamed the variable "class" as "classbits" to make life easier for C++
2739        users. (Previously there was a macro definition, but it apparently wasn't
2740        enough.)
2741    
2742    12. Added the new field "tables" to the extra data so that tables can be passed
2743        in at exec time, or the internal tables can be re-selected. This allows
2744        a compiled regex to be saved and re-used at a later time by a different
2745        program that might have everything at different addresses.
2746    
2747    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2748        -R library as well as a -L library.
2749    
2750    14. The debugging options of pcretest (-d on the command line or D on a
2751        pattern) showed incorrect output for anything following an extended class
2752        that contained multibyte characters and which was followed by a quantifier.
2753    
2754    15. Added optional support for general category Unicode character properties
2755        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2756        support. It adds about 90K to the size of the library. The meanings of the
2757        inbuilt class escapes such as \d and \s have NOT been changed.
2758    
2759    16. Updated pcredemo.c to include calls to free() to release the memory for the
2760        compiled pattern.
2761    
2762    17. The generated file chartables.c was being created in the source directory
2763        instead of in the building directory. This caused the build to fail if the
2764        source directory was different from the building directory, and was
2765        read-only.
2766    
2767    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2768        file. No doubt somebody will tell me if they don't make sense... Also added
2769        Dan Mooney's comments about building on OpenVMS.
2770    
2771    19. Added support for partial matching via the PCRE_PARTIAL option for
2772        pcre_exec() and the \P data escape in pcretest.
2773    
2774    20. Extended pcretest with 3 new pattern features:
2775    
2776        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2777              write the compiled pattern to the file whose name is "rest-of-line".
2778              This is a straight binary dump of the data, with the saved pointer to
2779              the character tables forced to be NULL. The study data, if any, is
2780              written too. After writing, pcretest reads a new pattern.
2781    
2782        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2783              compiled pattern from the given file. There must not be any
2784              occurrences of "<" in the file name (pretty unlikely); if there are,
2785              pcretest will instead treat the initial "<" as a pattern delimiter.
2786              After reading in the pattern, pcretest goes on to read data lines as
2787              usual.
2788    
2789        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2790              and 16-bit fields in a compiled pattern, to simulate a pattern that
2791              was compiled on a host of opposite endianness.
2792    
2793    21. The pcre-exec() function can now cope with patterns that were compiled on
2794        hosts of opposite endianness, with this restriction:
2795    
2796          As for any compiled expression that is saved and used later, the tables
2797          pointer field cannot be preserved; the extra_data field in the arguments
2798          to pcre_exec() should be used to pass in a tables address if a value
2799          other than the default internal tables were used at compile time.
2800    
2801    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2802        now diagnosed as an error. Previously, most of the time, a negative number
2803        would have been treated as zero, but if in addition "ovector" was passed as
2804        NULL, a crash could occur.
2805    
2806    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2807        new versions from the libtool 1.5 distribution (the last one is a copy of
2808        a file called libtool.m4). This seems to have fixed the need to patch
2809        "configure" to support Darwin 1.3 (which I used to do). However, I still
2810        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2811        workstation).
2812    
2813    24. Changed the PCRE licence to be the more standard "BSD" licence.
2814    
2815    
2816    Version 4.5 01-Dec-03
2817    ---------------------
2818    
2819     1. There has been some re-arrangement of the code for the match() function so
2820        that it can be compiled in a version that does not call itself recursively.
2821        Instead, it keeps those local variables that need separate instances for
2822        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2823        needs to "recurse". Keeping track of where control must go is done by means
2824        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2825        hide most of the details from the main code, and operates only if
2826        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2827        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2828        operating.
2829    
2830        To make it easier for callers to provide specially tailored get/free
2831        functions for this usage, two new functions, pcre_stack_malloc, and
2832        pcre_stack_free, are used. They are always called in strict stacking order,
2833        and the size of block requested is always the same.
2834    
2835        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2836        PCRE has been compiled to use the stack or the heap for recursion. The
2837        -C option of pcretest uses this to show which version is compiled.
2838    
2839        A new data escape \S, is added to pcretest; it causes the amounts of store
2840        obtained and freed by both kinds of malloc/free at match time to be added
2841        to the output.
2842    
2843     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2844        what's available on my current Linux desktop machine.
2845    
2846     3. When matching a UTF-8 string, the test for a valid string at the start has
2847        been extended. If start_offset is not zero, PCRE now checks that it points
2848        to a byte that is the start of a UTF-8 character. If not, it returns
2849        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2850        this is necessary because there may be backward assertions in the pattern.
2851        When matching the same subject several times, it may save resources to use
2852        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2853    
2854     4. The code for checking the validity of UTF-8 strings has been tightened so
2855        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2856        containing "overlong sequences".
2857    
2858     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2859        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2860        should have been "&", but it just so happened that all the cases this let
2861        through by mistake were picked up later in the function.
2862    
2863     6. I had used a variable called "isblank" - this is a C99 function, causing
2864        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2865    
2866     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2867        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2868        so the version is shown; (c) stop "make test" echoing "./RunTest".
2869    
2870     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2871    
2872     9. The prototype for memmove() for systems that don't have it was using
2873        size_t, but the inclusion of the header that defines size_t was later. I've
2874        moved the #includes for the C headers earlier to avoid this.
2875    
2876    10. Added some adjustments to the code to make it easier to compiler on certain
2877        special systems:
2878    
2879          (a) Some "const" qualifiers were missing.
2880          (b) Added the macro EXPORT before all exported functions; by default this
2881              is defined to be empty.
2882          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2883              that it reads its output file name as an argument instead of writing
2884              to the standard output and assuming this can be redirected.
2885    
2886    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2887        class containing characters with values greater than 255, PCRE compilation
2888        went into a loop.
2889    
2890    12. A recursive reference to a subpattern that was within another subpattern
2891        that had a minimum quantifier of zero caused PCRE to crash. For example,
2892        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2893        recursion. If the recursively-called subpattern itself had a zero repeat,
2894        that was OK.
2895    
2896    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2897        buffer into which it was copied (for escape processing) was still set at
2898        1024, so long lines caused crashes.
2899    
2900    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2901        "internal error: code overflow...". This applied to any character class
2902        that was followed by a possessive quantifier.
2903    
2904    15. Modified the Makefile to add libpcre.la as a prerequisite for
2905        libpcreposix.la because I was told this is needed for a parallel build to
2906        work.
2907    
2908    16. If a pattern that contained .* following optional items at the start was
2909        studied, the wrong optimizing data was generated, leading to matching
2910        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2911        matching string must start with a or b or c. The correct conclusion for
2912        this pattern is that a match can start with any character.
2913    
2914    
2915  Version 4.4 13-Aug-03  Version 4.4 13-Aug-03
2916  ---------------------  ---------------------
2917    

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