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

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