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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.9 xx-xxx-09  Version 8.13 02-Aug-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, now 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 now
111        *disables* studying, thereby overriding the use of -s on the command line
112        (see 14 above). This is necessary for one or two tests to keep the output
113        identical in both cases.
114    
115    21. When (*ACCEPT) was used in an assertion that matched an empty string and
116        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
117    
118    22. When an atomic group that contained a capturing parenthesis was
119        successfully matched, but the branch in which it appeared failed, the
120        capturing was not being forgotten if a higher numbered group was later
121        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
122        group 1 to "a", when in fact it should be unset. This applied to multi-
123        branched capturing and non-capturing groups, repeated or not, and also to
124        positive assertions (capturing in negative assertions does not happen
125        in PCRE) and also to nested atomic groups.
126    
127    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
128        subject after a captured substring, to make it easier to tell which of a
129        number of identical substrings has been captured.
130    
131    24. The way atomic groups are processed by pcre_exec() has been changed so that
132        if they are repeated, backtracking one repetition now resets captured
133        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
134        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
135        "aaa". Previously, it would have been "a". As part of this code
136        refactoring, the way recursive calls are handled has also been changed.
137    
138    25. If an assertion condition captured any substrings, they were not passed
139        back unless some other capturing happened later. For example, if
140        (?(?=(a))a) was matched against "a", no capturing was returned.
141    
142    26. When studying a pattern that contained subroutine calls or assertions,
143        the code for finding the minimum length of a possible match was handling
144        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
145        group 1 called group 2 while simultaneously a separate group 2 called group
146        1). A stack overflow occurred in this case. I have fixed this by limiting
147        the recursion depth to 10.
148    
149    27. Updated RunTest.bat in the distribution to the version supplied by Tom
150        Fortmann. This supports explicit test numbers on the command line, and has
151        argument validation and error reporting.
152    
153    28. An instance of \X with an unlimited repeat could fail if at any point the
154        first character it looked at was a mark character.
155    
156    29. Some minor code refactoring concerning Unicode properties and scripts
157        should reduce the stack requirement of match() slightly.
158    
159    30. Added the '=' option to pcretest to check the setting of unused capturing
160        slots at the end of the pattern, which are documented as being -1, but are
161        not included in the return count.
162    
163    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
164        compiled something random. Now it gives a compile-time error (as does
165        Perl).
166    
167    32. A *MARK encountered during the processing of a positive assertion is now
168        recorded and passed back (compatible with Perl).
169    
170    33. If --only-matching or --colour was set on a pcregrep call whose pattern
171        had alternative anchored branches, the search for a second match in a line
172        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
173        matched the line "0102" twice. The same bug affected patterns that started
174        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
175        twice.
176    
177    34. Previously, PCRE did not allow quantification of assertions. However, Perl
178        does, and because of capturing effects, quantifying parenthesized
179        assertions may at times be useful. Quantifiers are now allowed for
180        parenthesized assertions.
181    
182    35. A minor code tidy in pcre_compile() when checking options for \R usage.
183    
184    36. \g was being checked for fancy things in a character class, when it should
185        just be a literal "g".
186    
187    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
188        appearance of a nested POSIX class supersedes an apparent external class.
189        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
190        unescaped square brackets may also appear as part of class names. For
191        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
192        more like Perl.
193    
194    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
195        was because it thought it was \N{name}, which is not supported).
196    
197    39. Add minix to OS list not supporting the -S option in pcretest.
198    
199    40. PCRE tries to detect cases of infinite recursion at compile time, but it
200        cannot analyze patterns in sufficient detail to catch mutual recursions
201        such as ((?1))((?2)). There is now a runtime test that gives an error if a
202        subgroup is called recursively as a subpattern for a second time at the
203        same position in the subject string. In previous releases this might have
204        been caught by the recursion limit, or it might have run out of stack.
205    
206    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
207        happen only once. PCRE was, however incorrectly giving a compile time error
208        "recursive call could loop indefinitely" because it cannot analyze the
209        pattern in sufficient detail. The compile time test no longer happens when
210        PCRE is compiling a conditional subpattern, but actual runaway loops are
211        now caught at runtime (see 40 above).
212    
213    42. It seems that Perl allows any characters other than a closing parenthesis
214        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
215        has been changed to be the same.
216    
217    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
218        as not to get warnings when autogen.sh is called. Also changed
219        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
220    
221    44. To help people who use pcregrep to scan files containing exceedingly long
222        lines, the following changes have been made:
223    
224        (a) The default value of the buffer size parameter has been increased from
225            8K to 20K. (The actual buffer used is three times this size.)
226    
227        (b) The default can be changed by ./configure --with-pcregrep-bufsiz when
228            PCRE is built.
229    
230        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
231            to be set at run time.
232    
233        (d) Numerical values in pcregrep options can be followed by K or M, for
234            example --buffer-size=50K.
235    
236        (e) If a line being scanned overflows pcregrep's buffer, an error is now
237            given and the return code is set to 2.
238    
239    45. Add a pointer to the latest mark to the callout data block.
240    
241    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
242        partial match of an empty string instead of no match. This was specific to
243        the use of ".".
244    
245    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
246        complete match instead of a partial match. This bug was dependent on both
247        the PCRE_UTF8 and PCRE_DOTALL options being set.
248    
249    
250    Version 8.12 15-Jan-2011
251    ------------------------
252    
253    1.  Fixed some typos in the markup of the man pages, and wrote a script that
254        checks for such things as part of the documentation building process.
255    
256    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
257        --match-limit and --recursion-limit options (added for 8.11). In
258        particular, this made one of the standard tests fail. (The integer value
259        went into the wrong half of a long int.)
260    
261    3.  If the --colour option was given to pcregrep with -v (invert match), it
262        did strange things, either producing crazy output, or crashing. It should,
263        of course, ignore a request for colour when reporting lines that do not
264        match.
265    
266    4.  Another pcregrep bug caused similar problems if --colour was specified with
267        -M (multiline) and the pattern match finished with a line ending.
268    
269    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
270        matched in multiline mode, the following line was shown as part of the
271        match. This seems wrong, so I have changed it.
272    
273    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
274        the check for further matches in the same line (so they could be coloured)
275        to overrun the end of the current line. If another match was found, it was
276        incorrectly shown (and then shown again when found in the next line).
277    
278    7.  If pcregrep was compiled under Windows, there was a reference to the
279        function pcregrep_exit() before it was defined. I am assuming this was
280        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
281        reported by a user. I've moved the definition above the reference.
282    
283    
284    Version 8.11 10-Dec-2010
285    ------------------------
286    
287    1.  (*THEN) was not working properly if there were untried alternatives prior
288        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
289        backtracked to try for "b" instead of moving to the next alternative branch
290        at the same level (in this case, to look for "c"). The Perl documentation
291        is clear that when (*THEN) is backtracked onto, it goes to the "next
292        alternative in the innermost enclosing group".
293    
294    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
295        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
296        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
297        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
298        (*THEN).
299    
300    3.  If \s appeared in a character class, it removed the VT character from
301        the class, even if it had been included by some previous item, for example
302        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
303        of \s, but is part of the POSIX "space" class.)
304    
305    4.  A partial match never returns an empty string (because you can always
306        match an empty string at the end of the subject); however the checking for
307        an empty string was starting at the "start of match" point. This has been
308        changed to the "earliest inspected character" point, because the returned
309        data for a partial match starts at this character. This means that, for
310        example, /(?<=abc)def/ gives a partial match for the subject "abc"
311        (previously it gave "no match").
312    
313    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
314        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
315        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
316        has an implication that the given string is incomplete (because a partial
317        match is preferred over a full match). For this reason, these items now
318        give a partial match in this situation. [Aside: previously, the one case
319        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
320        match rather than a full match, which was wrong by the old rules, but is
321        now correct.]
322    
323    6.  There was a bug in the handling of #-introduced comments, recognized when
324        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
325        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
326        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
327        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
328        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
329        places in pcre_compile().
330    
331    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
332        comments when looking ahead for named forward references to subpatterns,
333        the only newline sequence it recognized was NL. It now handles newlines
334        according to the set newline convention.
335    
336    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
337        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
338        cater for a lack of strerror(). These oversights have been fixed.
339    
340    9.  Added --match-limit and --recursion-limit to pcregrep.
341    
342    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
343    
344    11. When the -o option was used, pcregrep was setting a return code of 1, even
345        when matches were found, and --line-buffered was not being honoured.
346    
347    12. Added an optional parentheses number to the -o and --only-matching options
348        of pcregrep.
349    
350    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
351        can match an empty string. The code to do it in pcretest and pcredemo
352        needed fixing:
353    
354        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
355            only one byte after an empty string match just before CRLF (this case
356            just got forgotten; "any" and "anycrlf" were OK).
357    
358        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
359            mode when an empty string match preceded an ASCII character followed by
360            a non-ASCII character. (The code for advancing by one character rather
361            than one byte was nonsense.)
362    
363        (c) The pcredemo.c sample program did not have any code at all to handle
364            the cases when CRLF is a valid newline sequence.
365    
366    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
367        as a starting offset was within the subject string. There is now a new
368        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
369        negative or greater than the length of the string. In order to test this,
370        pcretest is extended to allow the setting of negative starting offsets.
371    
372    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
373        starting offset points to the beginning of a UTF-8 character was
374        unnecessarily clumsy. I tidied it up.
375    
376    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
377        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
378    
379    17. Nobody had reported that the --include_dir option, which was added in
380        release 7.7 should have been called --include-dir (hyphen, not underscore)
381        for compatibility with GNU grep. I have changed it to --include-dir, but
382        left --include_dir as an undocumented synonym, and the same for
383        --exclude-dir, though that is not available in GNU grep, at least as of
384        release 2.5.4.
385    
386    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
387        characters from a string of bytes) have been redefined so as not to use
388        loops, in order to improve performance in some environments. At the same
389        time, I abstracted some of the common code into auxiliary macros to save
390        repetition (this should not affect the compiled code).
391    
392    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
393        compile-time error is now given if \c is not followed by an ASCII
394        character, that is, a byte less than 128. (In EBCDIC mode, the code is
395        different, and any byte value is allowed.)
396    
397    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
398        START_OPTIMIZE option, which is now allowed at compile time - but just
399        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
400        to pcregrep and other applications that have no direct access to PCRE
401        options. The new /Y option in pcretest sets this option when calling
402        pcre_compile().
403    
404    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
405        back references. Groups containing recursive back references were forced to
406        be atomic by that change, but in the case of named groups, the amount of
407        memory required was incorrectly computed, leading to "Failed: internal
408        error: code overflow". This has been fixed.
409    
410    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
411        pcretest.c, to avoid build problems in some Borland environments.
412    
413    
414    Version 8.10 25-Jun-2010
415    ------------------------
416    
417    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
418        THEN.
419    
420    2.  (*ACCEPT) was not working when inside an atomic group.
421    
422    3.  Inside a character class, \B is treated as a literal by default, but
423        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
424        causes the error). The code is unchanged, but I tidied the documentation.
425    
426    4.  Inside a character class, PCRE always treated \R and \X as literals,
427        whereas Perl faults them if its -w option is set. I have changed PCRE so
428        that it faults them when PCRE_EXTRA is set.
429    
430    5.  Added support for \N, which always matches any character other than
431        newline. (It is the same as "." when PCRE_DOTALL is not set.)
432    
433    6.  When compiling pcregrep with newer versions of gcc which may have
434        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
435        declared with attribute warn_unused_result" were given. Just casting the
436        result to (void) does not stop the warnings; a more elaborate fudge is
437        needed. I've used a macro to implement this.
438    
439    7.  Minor change to pcretest.c to avoid a compiler warning.
440    
441    8.  Added four artifical Unicode properties to help with an option to make
442        \s etc use properties (see next item). The new properties are: Xan
443        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
444    
445    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
446        use Unicode properties. (*UCP) at the start of a pattern can be used to set
447        this option. Modified pcretest to add /W to test this facility. Added
448        REG_UCP to make it available via the POSIX interface.
449    
450    10. Added --line-buffered to pcregrep.
451    
452    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
453        studied, and the match started with a letter with a code point greater than
454        127 whose first byte was different to the first byte of the other case of
455        the letter, the other case of this starting letter was not recognized
456        (#976).
457    
458    12. If a pattern that was studied started with a repeated Unicode property
459        test, for example, \p{Nd}+, there was the theoretical possibility of
460        setting up an incorrect bitmap of starting bytes, but fortunately it could
461        not have actually happened in practice until change 8 above was made (it
462        added property types that matched character-matching opcodes).
463    
464    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
465        possible starting bytes for non-anchored patterns.
466    
467    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
468        \R, and also a number of cases that involve Unicode properties, both
469        explicit and implicit when PCRE_UCP is set.
470    
471    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
472        input, it could crash or give wrong results if characters with values
473        greater than 0xc0 were present in the subject string. (Detail: it assumed
474        UTF-8 input when processing these items.)
475    
476    16. Added a lot of (int) casts to avoid compiler warnings in systems where
477        size_t is 64-bit (#991).
478    
479    17. Added a check for running out of memory when PCRE is compiled with
480        --disable-stack-for-recursion (#990).
481    
482    18. If the last data line in a file for pcretest does not have a newline on
483        the end, a newline was missing in the output.
484    
485    19. The default pcre_chartables.c file recognizes only ASCII characters (values
486        less than 128) in its various bitmaps. However, there is a facility for
487        generating tables according to the current locale when PCRE is compiled. It
488        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
489        characters, are recognized by isspace() and therefore were getting set in
490        these tables, and indeed these tables seem to approximate to ISO 8859. This
491        caused a problem in UTF-8 mode when pcre_study() was used to create a list
492        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
493        which of course cannot start UTF-8 characters. I have changed the code so
494        that only real ASCII characters (less than 128) and the correct starting
495        bytes for UTF-8 encodings are set for characters greater than 127 when in
496        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
497        altogether.)
498    
499    20. Added the /T option to pcretest so as to be able to run tests with non-
500        standard character tables, thus making it possible to include the tests
501        used for 19 above in the standard set of tests.
502    
503    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
504        reference to a subpattern the other side of a comment that contains an
505        opening parenthesis caused either an internal compiling error, or a
506        reference to the wrong subpattern.
507    
508    
509    Version 8.02 19-Mar-2010
510    ------------------------
511    
512    1.  The Unicode data tables have been updated to Unicode 5.2.0.
513    
514    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
515        configured.
516    
517    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
518        original author of that file, following a query about its status.
519    
520    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
521        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
522    
523    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
524        quantifier applied to a forward-referencing subroutine call, could compile
525        incorrect code or give the error "internal error: previously-checked
526        referenced subpattern not found".
527    
528    6.  Both MS Visual Studio and Symbian OS have problems with initializing
529        variables to point to external functions. For these systems, therefore,
530        pcre_malloc etc. are now initialized to local functions that call the
531        relevant global functions.
532    
533    7.  There were two entries missing in the vectors called coptable and poptable
534        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
535        I've fixed the data, and added a kludgy way of testing at compile time that
536        the lengths are correct (equal to the number of opcodes).
537    
538    8.  Following on from 7, I added a similar kludge to check the length of the
539        eint vector in pcreposix.c.
540    
541    9.  Error texts for pcre_compile() are held as one long string to avoid too
542        much relocation at load time. To find a text, the string is searched,
543        counting zeros. There was no check for running off the end of the string,
544        which could happen if a new error number was added without updating the
545        string.
546    
547    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
548    
549    11. \K was not working if it appeared in an atomic group or in a group that
550        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
551        \K is "not well defined" if used in an assertion. PCRE now accepts it if
552        the assertion is positive, but not if it is negative.
553    
554    12. Change 11 fortuitously reduced the size of the stack frame used in the
555        "match()" function of pcre_exec.c by one pointer. Forthcoming
556        implementation of support for (*MARK) will need an extra pointer on the
557        stack; I have reserved it now, so that the stack frame size does not
558        decrease.
559    
560    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
561        item in branch that calls a recursion is a subroutine call - as in the
562        second branch in the above example - was incorrectly given the compile-
563        time error "recursive call could loop indefinitely" because pcre_compile()
564        was not correctly checking the subroutine for matching a non-empty string.
565    
566    14. The checks for overrunning compiling workspace could trigger after an
567        overrun had occurred. This is a "should never occur" error, but it can be
568        triggered by pathological patterns such as hundreds of nested parentheses.
569        The checks now trigger 100 bytes before the end of the workspace.
570    
571    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
572    
573    
574    Version 8.01 19-Jan-2010
575    ------------------------
576    
577    1.  If a pattern contained a conditional subpattern with only one branch (in
578        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
579        computed the wrong minimum data length (which is of course zero for such
580        subpatterns). This could cause incorrect "no match" results.
581    
582    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
583        the pattern is reset in the first branch, pcre_compile() failed with
584        "internal error: code overflow at offset...". This happened only when
585        the reset was to the original external option setting. (An optimization
586        abstracts leading options settings into an external setting, which was the
587        cause of this.)
588    
589    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
590        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
591        assertion pattern did not match (meaning that the assertion was true), it
592        was incorrectly treated as false if the SKIP had been reached during the
593        matching. This also applied to assertions used as conditions.
594    
595    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
596        assertion subpattern, including such a pattern used as a condition,
597        unpredictable results occurred, instead of the error return
598        PCRE_ERROR_DFA_UITEM.
599    
600    5.  The C++ GlobalReplace function was not working like Perl for the special
601        situation when an empty string is matched. It now does the fancy magic
602        stuff that is necessary.
603    
604    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
605        removed. (These were left over from very, very early versions of PCRE.)
606    
607    7.  Some cosmetic changes to the code to make life easier when compiling it
608        as part of something else:
609    
610        (a) Change DEBUG to PCRE_DEBUG.
611    
612        (b) In pcre_compile(), rename the member of the "branch_chain" structure
613            called "current" as "current_branch", to prevent a collision with the
614            Linux macro when compiled as a kernel module.
615    
616        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
617            prevent a collision with the Linux macro when compiled as a kernel
618            module.
619    
620    8.  In pcre_compile() there are some checks for integer overflows that used to
621        cast potentially large values to (double). This has been changed to that
622        when building, a check for int64_t is made, and if it is found, it is used
623        instead, thus avoiding the use of floating point arithmetic. (There is no
624        other use of FP in PCRE.) If int64_t is not found, the fallback is to
625        double.
626    
627    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
628        2005 (difference between two addresses compared to an unsigned value).
629    
630    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
631        custom one, because of the following reported problem in Windows:
632    
633          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
634              under Win32.
635          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
636              therefore missing the function definition.
637          - The compiler thus generates a "C" signature for the test function.
638          - The linker fails to find the "C" function.
639          - PCRE fails to configure if asked to do so against libbz2.
640    
641    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
642        messages were output:
643    
644          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
645          rerunning libtoolize, to keep the correct libtool macros in-tree.
646          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
647    
648        I have done both of these things.
649    
650    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
651        most of the time, it *can* run out if it is given a pattern that contains a
652        runaway infinite recursion. I updated the discussion in the pcrestack man
653        page.
654    
655    13. Now that we have gone to the x.xx style of version numbers, the minor
656        version may start with zero. Using 08 or 09 is a bad idea because users
657        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
658        interpreted as invalid octal numbers. I've updated the previous comment in
659        configure.ac, and also added a check that gives an error if 08 or 09 are
660        used.
661    
662    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
663        causing partial matching to fail when the end of the subject matched \W
664        in a UTF-8 pattern where \W was quantified with a minimum of 3.
665    
666    15. There were some discrepancies between the declarations in pcre_internal.h
667        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
668        their definitions. The declarations used "const uschar *" and the
669        definitions used USPTR. Even though USPTR is normally defined as "const
670        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
671        reported that: "This difference in casting confuses some C++ compilers, for
672        example, SunCC recognizes above declarations as different functions and
673        generates broken code for hbpcre." I have changed the declarations to use
674        USPTR.
675    
676    16. GNU libtool is named differently on some systems. The autogen.sh script now
677        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
678        (FreeBSD).
679    
680    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
681        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
682        comment: "Figure out how to create a longlong from a string: strtoll and
683        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
684        instance, but it only takes 2 args instead of 3!"
685    
686    18. A subtle bug concerned with back references has been fixed by a change of
687        specification, with a corresponding code fix. A pattern such as
688        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
689        refers, was giving matches when it shouldn't. For example, xa=xaaa would
690        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
691        same bug. Such groups have to be quantified to be useful, or contained
692        inside another quantified group. (If there's no repetition, the reference
693        can never match.) The problem arises because, having left the group and
694        moved on to the rest of the pattern, a later failure that backtracks into
695        the group uses the captured value from the final iteration of the group
696        rather than the correct earlier one. I have fixed this in PCRE by forcing
697        any group that contains a reference to itself to be an atomic group; that
698        is, there cannot be any backtracking into it once it has completed. This is
699        similar to recursive and subroutine calls.
700    
701    
702    Version 8.00 19-Oct-09
703    ----------------------
704    
705    1.  The table for translating pcre_compile() error codes into POSIX error codes
706        was out-of-date, and there was no check on the pcre_compile() error code
707        being within the table. This could lead to an OK return being given in
708        error.
709    
710    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
711        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
712        in a Windows environment.
713    
714    3.  The pcregrep --count option prints the count for each file even when it is
715        zero, as does GNU grep. However, pcregrep was also printing all files when
716        --files-with-matches was added. Now, when both options are given, it prints
717        counts only for those files that have at least one match. (GNU grep just
718        prints the file name in this circumstance, but including the count seems
719        more useful - otherwise, why use --count?) Also ensured that the
720        combination -clh just lists non-zero counts, with no names.
721    
722    4.  The long form of the pcregrep -F option was incorrectly implemented as
723        --fixed_strings instead of --fixed-strings. This is an incompatible change,
724        but it seems right to fix it, and I didn't think it was worth preserving
725        the old behaviour.
726    
727    5.  The command line items --regex=pattern and --regexp=pattern were not
728        recognized by pcregrep, which required --regex pattern or --regexp pattern
729        (with a space rather than an '='). The man page documented the '=' forms,
730        which are compatible with GNU grep; these now work.
731    
732    6.  No libpcreposix.pc file was created for pkg-config; there was just
733        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
734    
735    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
736        when UCP support is not needed, by modifying the Python script that
737        generates it from Unicode data files. This should not matter if the module
738        is correctly used as a library, but I received one complaint about 50K of
739        unwanted data. My guess is that the person linked everything into his
740        program rather than using a library. Anyway, it does no harm.
741    
742    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
743        was a minimum greater than 1 for a wide character in a possessive
744        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
745        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
746        character. Chaos in the form of incorrect output or a compiling loop could
747        result.
748    
749    9.  The restrictions on what a pattern can contain when partial matching is
750        requested for pcre_exec() have been removed. All patterns can now be
751        partially matched by this function. In addition, if there are at least two
752        slots in the offset vector, the offset of the earliest inspected character
753        for the match and the offset of the end of the subject are set in them when
754        PCRE_ERROR_PARTIAL is returned.
755    
756    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
757        synonymous with PCRE_PARTIAL, for backwards compatibility, and
758        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
759        and may be more useful for multi-segment matching.
760    
761    11. Partial matching with pcre_exec() is now more intuitive. A partial match
762        used to be given if ever the end of the subject was reached; now it is
763        given only if matching could not proceed because another character was
764        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
765        string "Z", which now yields "no match" instead of "partial match". In the
766        case of pcre_dfa_exec(), "no match" is given if every matching path for the
767        final character ended with (*FAIL).
768    
769    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
770        if the pattern had a "must contain" character that was already found in the
771        earlier partial match, unless partial matching was again requested. For
772        example, with the pattern /dog.(body)?/, the "must contain" character is
773        "g". If the first part-match was for the string "dog", restarting with
774        "sbody" failed. This bug has been fixed.
775    
776    13. The string returned by pcre_dfa_exec() after a partial match has been
777        changed so that it starts at the first inspected character rather than the
778        first character of the match. This makes a difference only if the pattern
779        starts with a lookbehind assertion or \b or \B (\K is not supported by
780        pcre_dfa_exec()). It's an incompatible change, but it makes the two
781        matching functions compatible, and I think it's the right thing to do.
782    
783    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
784        so that the demonstration program is easily available in environments where
785        PCRE has not been installed from source.
786    
787    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
788        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
789        library.
790    
791    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
792        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
793        is not the first non-POSIX option to be added. Clearly some people find
794        these options useful.
795    
796    17. If a caller to the POSIX matching function regexec() passes a non-zero
797        value for nmatch with a NULL value for pmatch, the value of
798        nmatch is forced to zero.
799    
800    18. RunGrepTest did not have a test for the availability of the -u option of
801        the diff command, as RunTest does. It now checks in the same way as
802        RunTest, and also checks for the -b option.
803    
804    19. If an odd number of negated classes containing just a single character
805        interposed, within parentheses, between a forward reference to a named
806        subpattern and the definition of the subpattern, compilation crashed with
807        an internal error, complaining that it could not find the referenced
808        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
809        [The bug was that it was starting one character too far in when skipping
810        over the character class, thus treating the ] as data rather than
811        terminating the class. This meant it could skip too much.]
812    
813    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
814        /g option in pcretest when the pattern contains \K, which makes it possible
815        to have an empty string match not at the start, even when the pattern is
816        anchored. Updated pcretest and pcredemo to use this option.
817    
818    21. If the maximum number of capturing subpatterns in a recursion was greater
819        than the maximum at the outer level, the higher number was returned, but
820        with unset values at the outer level. The correct (outer level) value is
821        now given.
822    
823    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
824        PCRE did not set those parentheses (unlike Perl). I have now found a way to
825        make it do so. The string so far is captured, making this feature
826        compatible with Perl.
827    
828    23. The tests have been re-organized, adding tests 11 and 12, to make it
829        possible to check the Perl 5.10 features against Perl 5.10.
830    
831    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
832        pattern matches a fixed length string. PCRE did not allow this; now it
833        does. Neither allows recursion.
834    
835    25. I finally figured out how to implement a request to provide the minimum
836        length of subject string that was needed in order to match a given pattern.
837        (It was back references and recursion that I had previously got hung up
838        on.) This code has now been added to pcre_study(); it finds a lower bound
839        to the length of subject needed. It is not necessarily the greatest lower
840        bound, but using it to avoid searching strings that are too short does give
841        some useful speed-ups. The value is available to calling programs via
842        pcre_fullinfo().
843    
844    26. While implementing 25, I discovered to my embarrassment that pcretest had
845        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
846        study optimizations had never been tested with that matching function.
847        Oops. What is worse, even when it was passed study data, there was a bug in
848        pcre_dfa_exec() that meant it never actually used it. Double oops. There
849        were also very few tests of studied patterns with pcre_dfa_exec().
850    
851    27. If (?| is used to create subpatterns with duplicate numbers, they are now
852        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
853        on the other side of the coin, they are no longer allowed to have different
854        names, because these cannot be distinguished in PCRE, and this has caused
855        confusion. (This is a difference from Perl.)
856    
857    28. When duplicate subpattern names are present (necessarily with different
858        numbers, as required by 27 above), and a test is made by name in a
859        conditional pattern, either for a subpattern having been matched, or for
860        recursion in such a pattern, all the associated numbered subpatterns are
861        tested, and the overall condition is true if the condition is true for any
862        one of them. This is the way Perl works, and is also more like the way
863        testing by number works.
864    
865    
866    Version 7.9 11-Apr-09
867  ---------------------  ---------------------
868    
869  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 879  Version 7.9 xx-xxx-09
879      but BOOL is not.      but BOOL is not.
880    
881  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
882      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
883    
884  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
885      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 94  Version 7.9 xx-xxx-09 Line 956  Version 7.9 xx-xxx-09
956  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
957      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
958      included within another project.      included within another project.
959    
960  24. Steven Van Ingelgem's patches to add more options to the CMake support,  24. Steven Van Ingelgem's patches to add more options to the CMake support,
961      slightly modified by me:      slightly modified by me:
962    
963        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
964            not building pcregrep.            not building pcregrep.
965    
966        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
967            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
968    
969  25. Forward references, both numeric and by name, in patterns that made use of  25. Forward references, both numeric and by name, in patterns that made use of
970      duplicate group numbers, could behave incorrectly or give incorrect errors,      duplicate group numbers, could behave incorrectly or give incorrect errors,
971      because when scanning forward to find the reference group, PCRE was not      because when scanning forward to find the reference group, PCRE was not
972      taking into account the duplicate group numbers. A pattern such as      taking into account the duplicate group numbers. A pattern such as
973      ^X(?3)(a)(?|(b)|(q))(Y) is an example.      ^X(?3)(a)(?|(b)|(q))(Y) is an example.
974    
975    26. Changed a few more instances of "const unsigned char *" to USPTR, making
976        the feature of a custom pointer more persuasive (as requested by a user).
977    
978    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
979        pcretest.c, inside #ifndefs, because it seems they are sometimes already
980        pre-defined.
981    
982    28. Added support for (*UTF8) at the start of a pattern.
983    
984    29. Arrange for flags added by the "release type" setting in CMake to be shown
985        in the configuration summary.
986    
987    
988  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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