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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
14    
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
23    
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
28    
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
34    
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
38    
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
46    
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
55    
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
59    
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
62    
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
68    
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
72    
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
77    
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
86    
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
90    
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
95    
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
102    
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
106    
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
109    
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
113    
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
116    
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
125    
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
129    
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
136    
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
140    
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
147    
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
151    
152    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    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
168    
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
175    
176    33. Previously, PCRE did not allow quantification of assertions. However, Perl
177        does, and because of capturing effects, quantifying parenthesized
178        assertions may at times be useful. Quantifiers are now allowed for
179        parenthesized assertions.
180    
181    34. A minor code tidy in pcre_compile() when checking options for \R usage.
182    
183    35. \g was being checked for fancy things in a character class, when it should
184        just be a literal "g".
185    
186    36. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
187        appearance of a nested POSIX class supersedes an apparent external class.
188        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
189        unescaped square brackets may also appear as part of class names. For
190        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
191        more like Perl.
192    
193    37. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
194        was because it thought it was \N{name}, which is not supported).
195    
196    38. Add minix to OS list not supporting the -S option in pcretest.
197    
198    39. PCRE tries to detect cases of infinite recursion at compile time, but it
199        cannot analyze patterns in sufficient detail to catch mutual recursions
200        such as ((?1))((?2)). There is now a runtime test that gives an error if a
201        subgroup is called recursively as a subpattern for a second time at the
202        same position in the subject string. In previous releases this might have
203        been caught by the recursion limit, or it might have run out of stack.
204    
205    40. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
206        happen only once. PCRE was, however incorrectly giving a compile time error
207        "recursive call could loop indefinitely" because it cannot analyze the
208        pattern in sufficient detail. The compile time test no longer happens when
209        PCRE is compiling a conditional subpattern, but actual runaway loops are
210        now caught at runtime (see 39 above).
211    
212    41. It seems that Perl allows any characters other than a closing parenthesis
213        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
214        has been changed to be the same.
215    
216    42. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
217        as not to get warnings when autogen.sh is called. Also changed
218        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
219    
220    43. To help people who use pcregrep to scan files containing exceedingly long
221        lines, the following changes have been made:
222    
223        (a) The default value of the buffer size parameter has been increased from
224            8K to 20K. (A buffer three times this size is actually used.)
225    
226        (b) The default can be changed by ./configure --with-pcregrep-bufsiz when
227            PCRE is built.
228    
229        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
230            to be set at run time.
231    
232        (d) Numerical values in pcregrep options can be followed by K or M, for
233            example --buffer-size=50K.
234    
235        (e) If a line being scanned overflows pcregrep's buffer, an error is now
236            given and the return code is set to 2.
237    
238    44. Add a pointer to the latest mark to the callout data block.
239    
240    45. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
241        partial match of an empty string instead of no match. This was specific to
242        the use of ".".
243    
244    
245    Version 8.12 15-Jan-2011
246    ------------------------
247    
248    1.  Fixed some typos in the markup of the man pages, and wrote a script that
249        checks for such things as part of the documentation building process.
250    
251    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
252        --match-limit and --recursion-limit options (added for 8.11). In
253        particular, this made one of the standard tests fail. (The integer value
254        went into the wrong half of a long int.)
255    
256    3.  If the --colour option was given to pcregrep with -v (invert match), it
257        did strange things, either producing crazy output, or crashing. It should,
258        of course, ignore a request for colour when reporting lines that do not
259        match.
260    
261    4.  Another pcregrep bug caused similar problems if --colour was specified with
262        -M (multiline) and the pattern match finished with a line ending.
263    
264    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
265        matched in multiline mode, the following line was shown as part of the
266        match. This seems wrong, so I have changed it.
267    
268    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
269        the check for further matches in the same line (so they could be coloured)
270        to overrun the end of the current line. If another match was found, it was
271        incorrectly shown (and then shown again when found in the next line).
272    
273    7.  If pcregrep was compiled under Windows, there was a reference to the
274        function pcregrep_exit() before it was defined. I am assuming this was
275        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
276        reported by a user. I've moved the definition above the reference.
277    
278    
279    Version 8.11 10-Dec-2010
280    ------------------------
281    
282    1.  (*THEN) was not working properly if there were untried alternatives prior
283        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
284        backtracked to try for "b" instead of moving to the next alternative branch
285        at the same level (in this case, to look for "c"). The Perl documentation
286        is clear that when (*THEN) is backtracked onto, it goes to the "next
287        alternative in the innermost enclosing group".
288    
289    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
290        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
291        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
292        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
293        (*THEN).
294    
295    3.  If \s appeared in a character class, it removed the VT character from
296        the class, even if it had been included by some previous item, for example
297        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
298        of \s, but is part of the POSIX "space" class.)
299    
300    4.  A partial match never returns an empty string (because you can always
301        match an empty string at the end of the subject); however the checking for
302        an empty string was starting at the "start of match" point. This has been
303        changed to the "earliest inspected character" point, because the returned
304        data for a partial match starts at this character. This means that, for
305        example, /(?<=abc)def/ gives a partial match for the subject "abc"
306        (previously it gave "no match").
307    
308    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
309        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
310        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
311        has an implication that the given string is incomplete (because a partial
312        match is preferred over a full match). For this reason, these items now
313        give a partial match in this situation. [Aside: previously, the one case
314        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
315        match rather than a full match, which was wrong by the old rules, but is
316        now correct.]
317    
318    6.  There was a bug in the handling of #-introduced comments, recognized when
319        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
320        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
321        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
322        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
323        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
324        places in pcre_compile().
325    
326    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
327        comments when looking ahead for named forward references to subpatterns,
328        the only newline sequence it recognized was NL. It now handles newlines
329        according to the set newline convention.
330    
331    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
332        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
333        cater for a lack of strerror(). These oversights have been fixed.
334    
335    9.  Added --match-limit and --recursion-limit to pcregrep.
336    
337    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
338    
339    11. When the -o option was used, pcregrep was setting a return code of 1, even
340        when matches were found, and --line-buffered was not being honoured.
341    
342    12. Added an optional parentheses number to the -o and --only-matching options
343        of pcregrep.
344    
345    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
346        can match an empty string. The code to do it in pcretest and pcredemo
347        needed fixing:
348    
349        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
350            only one byte after an empty string match just before CRLF (this case
351            just got forgotten; "any" and "anycrlf" were OK).
352    
353        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
354            mode when an empty string match preceded an ASCII character followed by
355            a non-ASCII character. (The code for advancing by one character rather
356            than one byte was nonsense.)
357    
358        (c) The pcredemo.c sample program did not have any code at all to handle
359            the cases when CRLF is a valid newline sequence.
360    
361    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
362        as a starting offset was within the subject string. There is now a new
363        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
364        negative or greater than the length of the string. In order to test this,
365        pcretest is extended to allow the setting of negative starting offsets.
366    
367    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
368        starting offset points to the beginning of a UTF-8 character was
369        unnecessarily clumsy. I tidied it up.
370    
371    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
372        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
373    
374    17. Nobody had reported that the --include_dir option, which was added in
375        release 7.7 should have been called --include-dir (hyphen, not underscore)
376        for compatibility with GNU grep. I have changed it to --include-dir, but
377        left --include_dir as an undocumented synonym, and the same for
378        --exclude-dir, though that is not available in GNU grep, at least as of
379        release 2.5.4.
380    
381    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
382        characters from a string of bytes) have been redefined so as not to use
383        loops, in order to improve performance in some environments. At the same
384        time, I abstracted some of the common code into auxiliary macros to save
385        repetition (this should not affect the compiled code).
386    
387    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
388        compile-time error is now given if \c is not followed by an ASCII
389        character, that is, a byte less than 128. (In EBCDIC mode, the code is
390        different, and any byte value is allowed.)
391    
392    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
393        START_OPTIMIZE option, which is now allowed at compile time - but just
394        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
395        to pcregrep and other applications that have no direct access to PCRE
396        options. The new /Y option in pcretest sets this option when calling
397        pcre_compile().
398    
399    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
400        back references. Groups containing recursive back references were forced to
401        be atomic by that change, but in the case of named groups, the amount of
402        memory required was incorrectly computed, leading to "Failed: internal
403        error: code overflow". This has been fixed.
404    
405    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
406        pcretest.c, to avoid build problems in some Borland environments.
407    
408    
409    Version 8.10 25-Jun-2010
410    ------------------------
411    
412    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
413        THEN.
414    
415    2.  (*ACCEPT) was not working when inside an atomic group.
416    
417    3.  Inside a character class, \B is treated as a literal by default, but
418        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
419        causes the error). The code is unchanged, but I tidied the documentation.
420    
421    4.  Inside a character class, PCRE always treated \R and \X as literals,
422        whereas Perl faults them if its -w option is set. I have changed PCRE so
423        that it faults them when PCRE_EXTRA is set.
424    
425    5.  Added support for \N, which always matches any character other than
426        newline. (It is the same as "." when PCRE_DOTALL is not set.)
427    
428    6.  When compiling pcregrep with newer versions of gcc which may have
429        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
430        declared with attribute warn_unused_result" were given. Just casting the
431        result to (void) does not stop the warnings; a more elaborate fudge is
432        needed. I've used a macro to implement this.
433    
434    7.  Minor change to pcretest.c to avoid a compiler warning.
435    
436    8.  Added four artifical Unicode properties to help with an option to make
437        \s etc use properties (see next item). The new properties are: Xan
438        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
439    
440    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
441        use Unicode properties. (*UCP) at the start of a pattern can be used to set
442        this option. Modified pcretest to add /W to test this facility. Added
443        REG_UCP to make it available via the POSIX interface.
444    
445    10. Added --line-buffered to pcregrep.
446    
447    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
448        studied, and the match started with a letter with a code point greater than
449        127 whose first byte was different to the first byte of the other case of
450        the letter, the other case of this starting letter was not recognized
451        (#976).
452    
453    12. If a pattern that was studied started with a repeated Unicode property
454        test, for example, \p{Nd}+, there was the theoretical possibility of
455        setting up an incorrect bitmap of starting bytes, but fortunately it could
456        not have actually happened in practice until change 8 above was made (it
457        added property types that matched character-matching opcodes).
458    
459    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
460        possible starting bytes for non-anchored patterns.
461    
462    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
463        \R, and also a number of cases that involve Unicode properties, both
464        explicit and implicit when PCRE_UCP is set.
465    
466    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
467        input, it could crash or give wrong results if characters with values
468        greater than 0xc0 were present in the subject string. (Detail: it assumed
469        UTF-8 input when processing these items.)
470    
471    16. Added a lot of (int) casts to avoid compiler warnings in systems where
472        size_t is 64-bit (#991).
473    
474    17. Added a check for running out of memory when PCRE is compiled with
475        --disable-stack-for-recursion (#990).
476    
477    18. If the last data line in a file for pcretest does not have a newline on
478        the end, a newline was missing in the output.
479    
480    19. The default pcre_chartables.c file recognizes only ASCII characters (values
481        less than 128) in its various bitmaps. However, there is a facility for
482        generating tables according to the current locale when PCRE is compiled. It
483        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
484        characters, are recognized by isspace() and therefore were getting set in
485        these tables, and indeed these tables seem to approximate to ISO 8859. This
486        caused a problem in UTF-8 mode when pcre_study() was used to create a list
487        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
488        which of course cannot start UTF-8 characters. I have changed the code so
489        that only real ASCII characters (less than 128) and the correct starting
490        bytes for UTF-8 encodings are set for characters greater than 127 when in
491        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
492        altogether.)
493    
494    20. Added the /T option to pcretest so as to be able to run tests with non-
495        standard character tables, thus making it possible to include the tests
496        used for 19 above in the standard set of tests.
497    
498    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
499        reference to a subpattern the other side of a comment that contains an
500        opening parenthesis caused either an internal compiling error, or a
501        reference to the wrong subpattern.
502    
503    
504    Version 8.02 19-Mar-2010
505    ------------------------
506    
507    1.  The Unicode data tables have been updated to Unicode 5.2.0.
508    
509    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
510        configured.
511    
512    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
513        original author of that file, following a query about its status.
514    
515    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
516        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
517    
518    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
519        quantifier applied to a forward-referencing subroutine call, could compile
520        incorrect code or give the error "internal error: previously-checked
521        referenced subpattern not found".
522    
523    6.  Both MS Visual Studio and Symbian OS have problems with initializing
524        variables to point to external functions. For these systems, therefore,
525        pcre_malloc etc. are now initialized to local functions that call the
526        relevant global functions.
527    
528    7.  There were two entries missing in the vectors called coptable and poptable
529        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
530        I've fixed the data, and added a kludgy way of testing at compile time that
531        the lengths are correct (equal to the number of opcodes).
532    
533    8.  Following on from 7, I added a similar kludge to check the length of the
534        eint vector in pcreposix.c.
535    
536    9.  Error texts for pcre_compile() are held as one long string to avoid too
537        much relocation at load time. To find a text, the string is searched,
538        counting zeros. There was no check for running off the end of the string,
539        which could happen if a new error number was added without updating the
540        string.
541    
542    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
543    
544    11. \K was not working if it appeared in an atomic group or in a group that
545        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
546        \K is "not well defined" if used in an assertion. PCRE now accepts it if
547        the assertion is positive, but not if it is negative.
548    
549    12. Change 11 fortuitously reduced the size of the stack frame used in the
550        "match()" function of pcre_exec.c by one pointer. Forthcoming
551        implementation of support for (*MARK) will need an extra pointer on the
552        stack; I have reserved it now, so that the stack frame size does not
553        decrease.
554    
555    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
556        item in branch that calls a recursion is a subroutine call - as in the
557        second branch in the above example - was incorrectly given the compile-
558        time error "recursive call could loop indefinitely" because pcre_compile()
559        was not correctly checking the subroutine for matching a non-empty string.
560    
561    14. The checks for overrunning compiling workspace could trigger after an
562        overrun had occurred. This is a "should never occur" error, but it can be
563        triggered by pathological patterns such as hundreds of nested parentheses.
564        The checks now trigger 100 bytes before the end of the workspace.
565    
566    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
567    
568    
569    Version 8.01 19-Jan-2010
570    ------------------------
571    
572    1.  If a pattern contained a conditional subpattern with only one branch (in
573        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
574        computed the wrong minimum data length (which is of course zero for such
575        subpatterns). This could cause incorrect "no match" results.
576    
577    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
578        the pattern is reset in the first branch, pcre_compile() failed with
579        "internal error: code overflow at offset...". This happened only when
580        the reset was to the original external option setting. (An optimization
581        abstracts leading options settings into an external setting, which was the
582        cause of this.)
583    
584    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
585        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
586        assertion pattern did not match (meaning that the assertion was true), it
587        was incorrectly treated as false if the SKIP had been reached during the
588        matching. This also applied to assertions used as conditions.
589    
590    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
591        assertion subpattern, including such a pattern used as a condition,
592        unpredictable results occurred, instead of the error return
593        PCRE_ERROR_DFA_UITEM.
594    
595    5.  The C++ GlobalReplace function was not working like Perl for the special
596        situation when an empty string is matched. It now does the fancy magic
597        stuff that is necessary.
598    
599    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
600        removed. (These were left over from very, very early versions of PCRE.)
601    
602    7.  Some cosmetic changes to the code to make life easier when compiling it
603        as part of something else:
604    
605        (a) Change DEBUG to PCRE_DEBUG.
606    
607        (b) In pcre_compile(), rename the member of the "branch_chain" structure
608            called "current" as "current_branch", to prevent a collision with the
609            Linux macro when compiled as a kernel module.
610    
611        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
612            prevent a collision with the Linux macro when compiled as a kernel
613            module.
614    
615    8.  In pcre_compile() there are some checks for integer overflows that used to
616        cast potentially large values to (double). This has been changed to that
617        when building, a check for int64_t is made, and if it is found, it is used
618        instead, thus avoiding the use of floating point arithmetic. (There is no
619        other use of FP in PCRE.) If int64_t is not found, the fallback is to
620        double.
621    
622    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
623        2005 (difference between two addresses compared to an unsigned value).
624    
625    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
626        custom one, because of the following reported problem in Windows:
627    
628          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
629              under Win32.
630          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
631              therefore missing the function definition.
632          - The compiler thus generates a "C" signature for the test function.
633          - The linker fails to find the "C" function.
634          - PCRE fails to configure if asked to do so against libbz2.
635    
636    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
637        messages were output:
638    
639          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
640          rerunning libtoolize, to keep the correct libtool macros in-tree.
641          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
642    
643        I have done both of these things.
644    
645    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
646        most of the time, it *can* run out if it is given a pattern that contains a
647        runaway infinite recursion. I updated the discussion in the pcrestack man
648        page.
649    
650    13. Now that we have gone to the x.xx style of version numbers, the minor
651        version may start with zero. Using 08 or 09 is a bad idea because users
652        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
653        interpreted as invalid octal numbers. I've updated the previous comment in
654        configure.ac, and also added a check that gives an error if 08 or 09 are
655        used.
656    
657    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
658        causing partial matching to fail when the end of the subject matched \W
659        in a UTF-8 pattern where \W was quantified with a minimum of 3.
660    
661    15. There were some discrepancies between the declarations in pcre_internal.h
662        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
663        their definitions. The declarations used "const uschar *" and the
664        definitions used USPTR. Even though USPTR is normally defined as "const
665        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
666        reported that: "This difference in casting confuses some C++ compilers, for
667        example, SunCC recognizes above declarations as different functions and
668        generates broken code for hbpcre." I have changed the declarations to use
669        USPTR.
670    
671    16. GNU libtool is named differently on some systems. The autogen.sh script now
672        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
673        (FreeBSD).
674    
675    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
676        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
677        comment: "Figure out how to create a longlong from a string: strtoll and
678        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
679        instance, but it only takes 2 args instead of 3!"
680    
681    18. A subtle bug concerned with back references has been fixed by a change of
682        specification, with a corresponding code fix. A pattern such as
683        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
684        refers, was giving matches when it shouldn't. For example, xa=xaaa would
685        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
686        same bug. Such groups have to be quantified to be useful, or contained
687        inside another quantified group. (If there's no repetition, the reference
688        can never match.) The problem arises because, having left the group and
689        moved on to the rest of the pattern, a later failure that backtracks into
690        the group uses the captured value from the final iteration of the group
691        rather than the correct earlier one. I have fixed this in PCRE by forcing
692        any group that contains a reference to itself to be an atomic group; that
693        is, there cannot be any backtracking into it once it has completed. This is
694        similar to recursive and subroutine calls.
695    
696    
697    Version 8.00 19-Oct-09
698  ----------------------  ----------------------
699    
700  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
701      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
702      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
703      error.      error.
704    
705  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
706      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
707      in a Windows environment.      in a Windows environment.
708    
709  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
710      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
711      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
712      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
713      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
714      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
715      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
716    
717  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
718      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
719      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
720      the old behaviour.      the old behaviour.
721    
722  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
723      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
724      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
725      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
726    
727  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
728      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
729    
730  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
731      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
732      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
733      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
734      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
735      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
736    
737    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
738        was a minimum greater than 1 for a wide character in a possessive
739        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
740        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
741        character. Chaos in the form of incorrect output or a compiling loop could
742        result.
743    
744    9.  The restrictions on what a pattern can contain when partial matching is
745        requested for pcre_exec() have been removed. All patterns can now be
746        partially matched by this function. In addition, if there are at least two
747        slots in the offset vector, the offset of the earliest inspected character
748        for the match and the offset of the end of the subject are set in them when
749        PCRE_ERROR_PARTIAL is returned.
750    
751    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
752        synonymous with PCRE_PARTIAL, for backwards compatibility, and
753        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
754        and may be more useful for multi-segment matching.
755    
756    11. Partial matching with pcre_exec() is now more intuitive. A partial match
757        used to be given if ever the end of the subject was reached; now it is
758        given only if matching could not proceed because another character was
759        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
760        string "Z", which now yields "no match" instead of "partial match". In the
761        case of pcre_dfa_exec(), "no match" is given if every matching path for the
762        final character ended with (*FAIL).
763    
764    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
765        if the pattern had a "must contain" character that was already found in the
766        earlier partial match, unless partial matching was again requested. For
767        example, with the pattern /dog.(body)?/, the "must contain" character is
768        "g". If the first part-match was for the string "dog", restarting with
769        "sbody" failed. This bug has been fixed.
770    
771    13. The string returned by pcre_dfa_exec() after a partial match has been
772        changed so that it starts at the first inspected character rather than the
773        first character of the match. This makes a difference only if the pattern
774        starts with a lookbehind assertion or \b or \B (\K is not supported by
775        pcre_dfa_exec()). It's an incompatible change, but it makes the two
776        matching functions compatible, and I think it's the right thing to do.
777    
778    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
779        so that the demonstration program is easily available in environments where
780        PCRE has not been installed from source.
781    
782    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
783        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
784        library.
785    
786    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
787        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
788        is not the first non-POSIX option to be added. Clearly some people find
789        these options useful.
790    
791    17. If a caller to the POSIX matching function regexec() passes a non-zero
792        value for nmatch with a NULL value for pmatch, the value of
793        nmatch is forced to zero.
794    
795    18. RunGrepTest did not have a test for the availability of the -u option of
796        the diff command, as RunTest does. It now checks in the same way as
797        RunTest, and also checks for the -b option.
798    
799    19. If an odd number of negated classes containing just a single character
800        interposed, within parentheses, between a forward reference to a named
801        subpattern and the definition of the subpattern, compilation crashed with
802        an internal error, complaining that it could not find the referenced
803        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
804        [The bug was that it was starting one character too far in when skipping
805        over the character class, thus treating the ] as data rather than
806        terminating the class. This meant it could skip too much.]
807    
808    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
809        /g option in pcretest when the pattern contains \K, which makes it possible
810        to have an empty string match not at the start, even when the pattern is
811        anchored. Updated pcretest and pcredemo to use this option.
812    
813    21. If the maximum number of capturing subpatterns in a recursion was greater
814        than the maximum at the outer level, the higher number was returned, but
815        with unset values at the outer level. The correct (outer level) value is
816        now given.
817    
818    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
819        PCRE did not set those parentheses (unlike Perl). I have now found a way to
820        make it do so. The string so far is captured, making this feature
821        compatible with Perl.
822    
823    23. The tests have been re-organized, adding tests 11 and 12, to make it
824        possible to check the Perl 5.10 features against Perl 5.10.
825    
826    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
827        pattern matches a fixed length string. PCRE did not allow this; now it
828        does. Neither allows recursion.
829    
830    25. I finally figured out how to implement a request to provide the minimum
831        length of subject string that was needed in order to match a given pattern.
832        (It was back references and recursion that I had previously got hung up
833        on.) This code has now been added to pcre_study(); it finds a lower bound
834        to the length of subject needed. It is not necessarily the greatest lower
835        bound, but using it to avoid searching strings that are too short does give
836        some useful speed-ups. The value is available to calling programs via
837        pcre_fullinfo().
838    
839    26. While implementing 25, I discovered to my embarrassment that pcretest had
840        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
841        study optimizations had never been tested with that matching function.
842        Oops. What is worse, even when it was passed study data, there was a bug in
843        pcre_dfa_exec() that meant it never actually used it. Double oops. There
844        were also very few tests of studied patterns with pcre_dfa_exec().
845    
846    27. If (?| is used to create subpatterns with duplicate numbers, they are now
847        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
848        on the other side of the coin, they are no longer allowed to have different
849        names, because these cannot be distinguished in PCRE, and this has caused
850        confusion. (This is a difference from Perl.)
851    
852    28. When duplicate subpattern names are present (necessarily with different
853        numbers, as required by 27 above), and a test is made by name in a
854        conditional pattern, either for a subpattern having been matched, or for
855        recursion in such a pattern, all the associated numbered subpatterns are
856        tested, and the overall condition is true if the condition is true for any
857        one of them. This is the way Perl works, and is also more like the way
858        testing by number works.
859    
860    
861  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
862  ---------------------  ---------------------

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