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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.20
5    ------------
7    1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8       a POSIX class. After further experiments with Perl, which convinced me that
9       Perl has bugs and confusions, a closing square bracket is no longer allowed
10       in a POSIX name.
12    2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
13       substring, but while checking the failing first alternative, substring 1 is
14       temporarily captured. If the output vector supplied to pcre_exec() was not
15       big enough for this capture, the yield of the function was still zero
16       ("insufficient space for captured substrings"). This cannot be totally fixed
17       without adding another stack variable, which seems a lot of expense for a
18       edge case. However, I have improved the situation in cases such as
19       /(a)(b)x|abc/ matched against "abc", where the return code indicates that
20       fewer than the maximum number of slots in the ovector have been set.
22    3. Related to (2) above: when there are more back references in a pattern than
23       slots in the output vector, pcre_exec() uses temporary memory during
24       matching, and copies in the captures as far as possible afterwards. It was
25       using the entire output vector, but this conflicts with the specification
26       that only 2/3 is used for passing back captured substrings. Now it uses only
27       the first 2/3, for compatibility. This is, of course, another edge case.
29    4. Zoltan Herczeg's just-in-time compiler support has been integrated into the
30       main code base, and can be used by building with --enable-jit.
32    5. When the number of matches in a pcre_dfa_exec() run exactly filled the
33       ovector, the return from the function was zero, implying that there were
34       other matches that did not fit. The correct "exactly full" value is now
35       returned.
37    6. If a subpattern that was called recursively or as a subroutine contained
38       (*PRUNE) or any other control that caused it to give a non-standard return,
39       invalid errors such as "Error -26 (nested recursion at the same subject
40       position)" or even infinite loops could occur.
43    Version 8.13 16-Aug-2011
44    ------------------------
46    1.  The Unicode data tables have been updated to Unicode 6.0.0.
48    2.  Two minor typos in pcre_internal.h have been fixed.
50    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
51        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
52        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
54    4.  There were a number of related bugs in the code for matching backrefences
55        caselessly in UTF-8 mode when codes for the characters concerned were
56        different numbers of bytes. For example, U+023A and U+2C65 are an upper
57        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
58        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
59        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
60        2-byte code at the end of the subject (it thought there wasn't enough data
61        left).
63    5.  Comprehensive information about what went wrong is now returned by
64        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
65        as the output vector has at least 2 elements. The offset of the start of
66        the failing character and a reason code are placed in the vector.
68    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
69        now returned is for the first byte of the failing character, instead of the
70        last byte inspected. This is an incompatible change, but I hope it is small
71        enough not to be a problem. It makes the returned offset consistent with
72        pcre_exec() and pcre_dfa_exec().
74    7.  pcretest now gives a text phrase as well as the error number when
75        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
76        failure, the offset and reason code are output.
78    8.  When \R was used with a maximizing quantifier it failed to skip backwards
79        over a \r\n pair if the subsequent match failed. Instead, it just skipped
80        back over a single character (\n). This seems wrong (because it treated the
81        two characters as a single entity when going forwards), conflicts with the
82        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
83        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
84        has been changed.
86    9.  Some internal refactoring has changed the processing so that the handling
87        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
88        time (the PCRE_DOTALL option was changed this way some time ago: version
89        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
90        which was always a bit of a fudge. It also means that there is one less
91        argument for the match() function, which reduces its stack requirements
92        slightly. This change also fixes an incompatibility with Perl: the pattern
93        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
95    10. More internal refactoring has drastically reduced the number of recursive
96        calls to match() for possessively repeated groups such as (abc)++ when
97        using pcre_exec().
99    11. While implementing 10, a number of bugs in the handling of groups were
100        discovered and fixed:
102        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
103        (a|)*(?1) gave a compile-time internal error.
104        ((a|)+)+  did not notice that the outer group could match an empty string.
105        (^a|^)+   was not marked as anchored.
106        (.*a|.*)+ was not marked as matching at start or after a newline.
108    12. Yet more internal refactoring has removed another argument from the match()
109        function. Special calls to this function are now indicated by setting a
110        value in a variable in the "match data" data block.
112    13. Be more explicit in pcre_study() instead of relying on "default" for
113        opcodes that mean there is no starting character; this means that when new
114        ones are added and accidentally left out of pcre_study(), testing should
115        pick them up.
117    14. The -s option of pcretest has been documented for ages as being an old
118        synonym of -m (show memory usage). I have changed it to mean "force study
119        for every regex", that is, assume /S for every regex. This is similar to -i
120        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
121        using it. It makes it easier to run collections of tests with and without
122        study enabled, and thereby test pcre_study() more easily. All the standard
123        tests are now run with and without -s (but some patterns can be marked as
124        "never study" - see 20 below).
126    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
127        restoration of the capturing data to the outer values was not happening
128        correctly.
130    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
131        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
132        pattern had matched an empty string, and so incorrectly returned a no
133        match.
135    17. There was optimizing code for the last branch of non-capturing parentheses,
136        and also for the obeyed branch of a conditional subexpression, which used
137        tail recursion to cut down on stack usage. Unfortunately, now that there is
138        the possibility of (*THEN) occurring in these branches, tail recursion is
139        no longer possible because the return has to be checked for (*THEN). These
140        two optimizations have therefore been removed.
142    18. If a pattern containing \R was studied, it was assumed that \R always
143        matched two bytes, thus causing the minimum subject length to be
144        incorrectly computed because \R can also match just one byte.
146    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
147        was incorrectly computed.
149    20. If /S is present twice on a test pattern in pcretest input, it now
150        *disables* studying, thereby overriding the use of -s on the command line
151        (see 14 above). This is necessary for one or two tests to keep the output
152        identical in both cases.
154    21. When (*ACCEPT) was used in an assertion that matched an empty string and
155        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
157    22. When an atomic group that contained a capturing parenthesis was
158        successfully matched, but the branch in which it appeared failed, the
159        capturing was not being forgotten if a higher numbered group was later
160        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
161        group 1 to "a", when in fact it should be unset. This applied to multi-
162        branched capturing and non-capturing groups, repeated or not, and also to
163        positive assertions (capturing in negative assertions does not happen
164        in PCRE) and also to nested atomic groups.
166    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
167        subject after a captured substring, to make it easier to tell which of a
168        number of identical substrings has been captured.
170    24. The way atomic groups are processed by pcre_exec() has been changed so that
171        if they are repeated, backtracking one repetition now resets captured
172        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
173        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
174        "aaa". Previously, it would have been "a". As part of this code
175        refactoring, the way recursive calls are handled has also been changed.
177    25. If an assertion condition captured any substrings, they were not passed
178        back unless some other capturing happened later. For example, if
179        (?(?=(a))a) was matched against "a", no capturing was returned.
181    26. When studying a pattern that contained subroutine calls or assertions,
182        the code for finding the minimum length of a possible match was handling
183        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
184        group 1 called group 2 while simultaneously a separate group 2 called group
185        1). A stack overflow occurred in this case. I have fixed this by limiting
186        the recursion depth to 10.
188    27. Updated RunTest.bat in the distribution to the version supplied by Tom
189        Fortmann. This supports explicit test numbers on the command line, and has
190        argument validation and error reporting.
192    28. An instance of \X with an unlimited repeat could fail if at any point the
193        first character it looked at was a mark character.
195    29. Some minor code refactoring concerning Unicode properties and scripts
196        should reduce the stack requirement of match() slightly.
198    30. Added the '=' option to pcretest to check the setting of unused capturing
199        slots at the end of the pattern, which are documented as being -1, but are
200        not included in the return count.
202    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
203        compiled something random. Now it gives a compile-time error (as does
204        Perl).
206    32. A *MARK encountered during the processing of a positive assertion is now
207        recorded and passed back (compatible with Perl).
209    33. If --only-matching or --colour was set on a pcregrep call whose pattern
210        had alternative anchored branches, the search for a second match in a line
211        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
212        matched the line "0102" twice. The same bug affected patterns that started
213        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
214        twice.
216    34. Previously, PCRE did not allow quantification of assertions. However, Perl
217        does, and because of capturing effects, quantifying parenthesized
218        assertions may at times be useful. Quantifiers are now allowed for
219        parenthesized assertions.
221    35. A minor code tidy in pcre_compile() when checking options for \R usage.
223    36. \g was being checked for fancy things in a character class, when it should
224        just be a literal "g".
226    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
227        appearance of a nested POSIX class supersedes an apparent external class.
228        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
229        unescaped square brackets may also appear as part of class names. For
230        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
231        more like Perl. (But see 8.20/1 above.)
233    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
234        was because it thought it was \N{name}, which is not supported).
236    39. Add minix to OS list not supporting the -S option in pcretest.
238    40. PCRE tries to detect cases of infinite recursion at compile time, but it
239        cannot analyze patterns in sufficient detail to catch mutual recursions
240        such as ((?1))((?2)). There is now a runtime test that gives an error if a
241        subgroup is called recursively as a subpattern for a second time at the
242        same position in the subject string. In previous releases this might have
243        been caught by the recursion limit, or it might have run out of stack.
245    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
246        happen only once. PCRE was, however incorrectly giving a compile time error
247        "recursive call could loop indefinitely" because it cannot analyze the
248        pattern in sufficient detail. The compile time test no longer happens when
249        PCRE is compiling a conditional subpattern, but actual runaway loops are
250        now caught at runtime (see 40 above).
252    42. It seems that Perl allows any characters other than a closing parenthesis
253        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
254        has been changed to be the same.
256    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
257        as not to get warnings when autogen.sh is called. Also changed
258        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
260    44. To help people who use pcregrep to scan files containing exceedingly long
261        lines, the following changes have been made:
263        (a) The default value of the buffer size parameter has been increased from
264            8K to 20K. (The actual buffer used is three times this size.)
266        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
267            PCRE is built.
269        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
270            to be set at run time.
272        (d) Numerical values in pcregrep options can be followed by K or M, for
273            example --buffer-size=50K.
275        (e) If a line being scanned overflows pcregrep's buffer, an error is now
276            given and the return code is set to 2.
278    45. Add a pointer to the latest mark to the callout data block.
280    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
281        partial match of an empty string instead of no match. This was specific to
282        the use of ".".
284    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
285        complete match instead of a partial match. This bug was dependent on both
286        the PCRE_UTF8 and PCRE_DOTALL options being set.
288    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
289        starting byte set, because \b was not being ignored.
292    Version 8.12 15-Jan-2011
293    ------------------------
295    1.  Fixed some typos in the markup of the man pages, and wrote a script that
296        checks for such things as part of the documentation building process.
298    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
299        --match-limit and --recursion-limit options (added for 8.11). In
300        particular, this made one of the standard tests fail. (The integer value
301        went into the wrong half of a long int.)
303    3.  If the --colour option was given to pcregrep with -v (invert match), it
304        did strange things, either producing crazy output, or crashing. It should,
305        of course, ignore a request for colour when reporting lines that do not
306        match.
308    4.  Another pcregrep bug caused similar problems if --colour was specified with
309        -M (multiline) and the pattern match finished with a line ending.
311    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
312        matched in multiline mode, the following line was shown as part of the
313        match. This seems wrong, so I have changed it.
315    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
316        the check for further matches in the same line (so they could be coloured)
317        to overrun the end of the current line. If another match was found, it was
318        incorrectly shown (and then shown again when found in the next line).
320    7.  If pcregrep was compiled under Windows, there was a reference to the
321        function pcregrep_exit() before it was defined. I am assuming this was
322        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
323        reported by a user. I've moved the definition above the reference.
326    Version 8.11 10-Dec-2010
327    ------------------------
329    1.  (*THEN) was not working properly if there were untried alternatives prior
330        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
331        backtracked to try for "b" instead of moving to the next alternative branch
332        at the same level (in this case, to look for "c"). The Perl documentation
333        is clear that when (*THEN) is backtracked onto, it goes to the "next
334        alternative in the innermost enclosing group".
336    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
337        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
338        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
339        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
340        (*THEN).
342    3.  If \s appeared in a character class, it removed the VT character from
343        the class, even if it had been included by some previous item, for example
344        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
345        of \s, but is part of the POSIX "space" class.)
347    4.  A partial match never returns an empty string (because you can always
348        match an empty string at the end of the subject); however the checking for
349        an empty string was starting at the "start of match" point. This has been
350        changed to the "earliest inspected character" point, because the returned
351        data for a partial match starts at this character. This means that, for
352        example, /(?<=abc)def/ gives a partial match for the subject "abc"
353        (previously it gave "no match").
355    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
356        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
357        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
358        has an implication that the given string is incomplete (because a partial
359        match is preferred over a full match). For this reason, these items now
360        give a partial match in this situation. [Aside: previously, the one case
361        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
362        match rather than a full match, which was wrong by the old rules, but is
363        now correct.]
365    6.  There was a bug in the handling of #-introduced comments, recognized when
366        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
367        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
368        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
369        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
370        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
371        places in pcre_compile().
373    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
374        comments when looking ahead for named forward references to subpatterns,
375        the only newline sequence it recognized was NL. It now handles newlines
376        according to the set newline convention.
378    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
379        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
380        cater for a lack of strerror(). These oversights have been fixed.
382    9.  Added --match-limit and --recursion-limit to pcregrep.
384    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
386    11. When the -o option was used, pcregrep was setting a return code of 1, even
387        when matches were found, and --line-buffered was not being honoured.
389    12. Added an optional parentheses number to the -o and --only-matching options
390        of pcregrep.
392    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
393        can match an empty string. The code to do it in pcretest and pcredemo
394        needed fixing:
396        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
397            only one byte after an empty string match just before CRLF (this case
398            just got forgotten; "any" and "anycrlf" were OK).
400        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
401            mode when an empty string match preceded an ASCII character followed by
402            a non-ASCII character. (The code for advancing by one character rather
403            than one byte was nonsense.)
405        (c) The pcredemo.c sample program did not have any code at all to handle
406            the cases when CRLF is a valid newline sequence.
408    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
409        as a starting offset was within the subject string. There is now a new
410        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
411        negative or greater than the length of the string. In order to test this,
412        pcretest is extended to allow the setting of negative starting offsets.
414    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
415        starting offset points to the beginning of a UTF-8 character was
416        unnecessarily clumsy. I tidied it up.
418    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
419        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
421    17. Nobody had reported that the --include_dir option, which was added in
422        release 7.7 should have been called --include-dir (hyphen, not underscore)
423        for compatibility with GNU grep. I have changed it to --include-dir, but
424        left --include_dir as an undocumented synonym, and the same for
425        --exclude-dir, though that is not available in GNU grep, at least as of
426        release 2.5.4.
428    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
429        characters from a string of bytes) have been redefined so as not to use
430        loops, in order to improve performance in some environments. At the same
431        time, I abstracted some of the common code into auxiliary macros to save
432        repetition (this should not affect the compiled code).
434    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
435        compile-time error is now given if \c is not followed by an ASCII
436        character, that is, a byte less than 128. (In EBCDIC mode, the code is
437        different, and any byte value is allowed.)
439    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
440        START_OPTIMIZE option, which is now allowed at compile time - but just
441        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
442        to pcregrep and other applications that have no direct access to PCRE
443        options. The new /Y option in pcretest sets this option when calling
444        pcre_compile().
446    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
447        back references. Groups containing recursive back references were forced to
448        be atomic by that change, but in the case of named groups, the amount of
449        memory required was incorrectly computed, leading to "Failed: internal
450        error: code overflow". This has been fixed.
452    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
453        pcretest.c, to avoid build problems in some Borland environments.
456    Version 8.10 25-Jun-2010
457    ------------------------
459    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
460        THEN.
462    2.  (*ACCEPT) was not working when inside an atomic group.
464    3.  Inside a character class, \B is treated as a literal by default, but
465        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
466        causes the error). The code is unchanged, but I tidied the documentation.
468    4.  Inside a character class, PCRE always treated \R and \X as literals,
469        whereas Perl faults them if its -w option is set. I have changed PCRE so
470        that it faults them when PCRE_EXTRA is set.
472    5.  Added support for \N, which always matches any character other than
473        newline. (It is the same as "." when PCRE_DOTALL is not set.)
475    6.  When compiling pcregrep with newer versions of gcc which may have
476        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
477        declared with attribute warn_unused_result" were given. Just casting the
478        result to (void) does not stop the warnings; a more elaborate fudge is
479        needed. I've used a macro to implement this.
481    7.  Minor change to pcretest.c to avoid a compiler warning.
483    8.  Added four artifical Unicode properties to help with an option to make
484        \s etc use properties (see next item). The new properties are: Xan
485        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
487    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
488        use Unicode properties. (*UCP) at the start of a pattern can be used to set
489        this option. Modified pcretest to add /W to test this facility. Added
490        REG_UCP to make it available via the POSIX interface.
492    10. Added --line-buffered to pcregrep.
494    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
495        studied, and the match started with a letter with a code point greater than
496        127 whose first byte was different to the first byte of the other case of
497        the letter, the other case of this starting letter was not recognized
498        (#976).
500    12. If a pattern that was studied started with a repeated Unicode property
501        test, for example, \p{Nd}+, there was the theoretical possibility of
502        setting up an incorrect bitmap of starting bytes, but fortunately it could
503        not have actually happened in practice until change 8 above was made (it
504        added property types that matched character-matching opcodes).
506    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
507        possible starting bytes for non-anchored patterns.
509    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
510        \R, and also a number of cases that involve Unicode properties, both
511        explicit and implicit when PCRE_UCP is set.
513    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
514        input, it could crash or give wrong results if characters with values
515        greater than 0xc0 were present in the subject string. (Detail: it assumed
516        UTF-8 input when processing these items.)
518    16. Added a lot of (int) casts to avoid compiler warnings in systems where
519        size_t is 64-bit (#991).
521    17. Added a check for running out of memory when PCRE is compiled with
522        --disable-stack-for-recursion (#990).
524    18. If the last data line in a file for pcretest does not have a newline on
525        the end, a newline was missing in the output.
527    19. The default pcre_chartables.c file recognizes only ASCII characters (values
528        less than 128) in its various bitmaps. However, there is a facility for
529        generating tables according to the current locale when PCRE is compiled. It
530        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
531        characters, are recognized by isspace() and therefore were getting set in
532        these tables, and indeed these tables seem to approximate to ISO 8859. This
533        caused a problem in UTF-8 mode when pcre_study() was used to create a list
534        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
535        which of course cannot start UTF-8 characters. I have changed the code so
536        that only real ASCII characters (less than 128) and the correct starting
537        bytes for UTF-8 encodings are set for characters greater than 127 when in
538        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
539        altogether.)
541    20. Added the /T option to pcretest so as to be able to run tests with non-
542        standard character tables, thus making it possible to include the tests
543        used for 19 above in the standard set of tests.
545    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
546        reference to a subpattern the other side of a comment that contains an
547        opening parenthesis caused either an internal compiling error, or a
548        reference to the wrong subpattern.
551    Version 8.02 19-Mar-2010
552    ------------------------
554    1.  The Unicode data tables have been updated to Unicode 5.2.0.
556    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
557        configured.
559    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
560        original author of that file, following a query about its status.
562    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
563        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
565    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
566        quantifier applied to a forward-referencing subroutine call, could compile
567        incorrect code or give the error "internal error: previously-checked
568        referenced subpattern not found".
570    6.  Both MS Visual Studio and Symbian OS have problems with initializing
571        variables to point to external functions. For these systems, therefore,
572        pcre_malloc etc. are now initialized to local functions that call the
573        relevant global functions.
575    7.  There were two entries missing in the vectors called coptable and poptable
576        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
577        I've fixed the data, and added a kludgy way of testing at compile time that
578        the lengths are correct (equal to the number of opcodes).
580    8.  Following on from 7, I added a similar kludge to check the length of the
581        eint vector in pcreposix.c.
583    9.  Error texts for pcre_compile() are held as one long string to avoid too
584        much relocation at load time. To find a text, the string is searched,
585        counting zeros. There was no check for running off the end of the string,
586        which could happen if a new error number was added without updating the
587        string.
589    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
591    11. \K was not working if it appeared in an atomic group or in a group that
592        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
593        \K is "not well defined" if used in an assertion. PCRE now accepts it if
594        the assertion is positive, but not if it is negative.
596    12. Change 11 fortuitously reduced the size of the stack frame used in the
597        "match()" function of pcre_exec.c by one pointer. Forthcoming
598        implementation of support for (*MARK) will need an extra pointer on the
599        stack; I have reserved it now, so that the stack frame size does not
600        decrease.
602    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
603        item in branch that calls a recursion is a subroutine call - as in the
604        second branch in the above example - was incorrectly given the compile-
605        time error "recursive call could loop indefinitely" because pcre_compile()
606        was not correctly checking the subroutine for matching a non-empty string.
608    14. The checks for overrunning compiling workspace could trigger after an
609        overrun had occurred. This is a "should never occur" error, but it can be
610        triggered by pathological patterns such as hundreds of nested parentheses.
611        The checks now trigger 100 bytes before the end of the workspace.
613    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
616    Version 8.01 19-Jan-2010
617    ------------------------
619    1.  If a pattern contained a conditional subpattern with only one branch (in
620        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
621        computed the wrong minimum data length (which is of course zero for such
622        subpatterns). This could cause incorrect "no match" results.
624    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
625        the pattern is reset in the first branch, pcre_compile() failed with
626        "internal error: code overflow at offset...". This happened only when
627        the reset was to the original external option setting. (An optimization
628        abstracts leading options settings into an external setting, which was the
629        cause of this.)
631    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
632        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
633        assertion pattern did not match (meaning that the assertion was true), it
634        was incorrectly treated as false if the SKIP had been reached during the
635        matching. This also applied to assertions used as conditions.
637    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
638        assertion subpattern, including such a pattern used as a condition,
639        unpredictable results occurred, instead of the error return
642    5.  The C++ GlobalReplace function was not working like Perl for the special
643        situation when an empty string is matched. It now does the fancy magic
644        stuff that is necessary.
646    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
647        removed. (These were left over from very, very early versions of PCRE.)
649    7.  Some cosmetic changes to the code to make life easier when compiling it
650        as part of something else:
652        (a) Change DEBUG to PCRE_DEBUG.
654        (b) In pcre_compile(), rename the member of the "branch_chain" structure
655            called "current" as "current_branch", to prevent a collision with the
656            Linux macro when compiled as a kernel module.
658        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
659            prevent a collision with the Linux macro when compiled as a kernel
660            module.
662    8.  In pcre_compile() there are some checks for integer overflows that used to
663        cast potentially large values to (double). This has been changed to that
664        when building, a check for int64_t is made, and if it is found, it is used
665        instead, thus avoiding the use of floating point arithmetic. (There is no
666        other use of FP in PCRE.) If int64_t is not found, the fallback is to
667        double.
669    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
670        2005 (difference between two addresses compared to an unsigned value).
672    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
673        custom one, because of the following reported problem in Windows:
675          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
676              under Win32.
677          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
678              therefore missing the function definition.
679          - The compiler thus generates a "C" signature for the test function.
680          - The linker fails to find the "C" function.
681          - PCRE fails to configure if asked to do so against libbz2.
683    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
684        messages were output:
686          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
687          rerunning libtoolize, to keep the correct libtool macros in-tree.
688          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
690        I have done both of these things.
692    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
693        most of the time, it *can* run out if it is given a pattern that contains a
694        runaway infinite recursion. I updated the discussion in the pcrestack man
695        page.
697    13. Now that we have gone to the x.xx style of version numbers, the minor
698        version may start with zero. Using 08 or 09 is a bad idea because users
699        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
700        interpreted as invalid octal numbers. I've updated the previous comment in
701        configure.ac, and also added a check that gives an error if 08 or 09 are
702        used.
704    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
705        causing partial matching to fail when the end of the subject matched \W
706        in a UTF-8 pattern where \W was quantified with a minimum of 3.
708    15. There were some discrepancies between the declarations in pcre_internal.h
709        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
710        their definitions. The declarations used "const uschar *" and the
711        definitions used USPTR. Even though USPTR is normally defined as "const
712        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
713        reported that: "This difference in casting confuses some C++ compilers, for
714        example, SunCC recognizes above declarations as different functions and
715        generates broken code for hbpcre." I have changed the declarations to use
716        USPTR.
718    16. GNU libtool is named differently on some systems. The autogen.sh script now
719        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
720        (FreeBSD).
722    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
723        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
724        comment: "Figure out how to create a longlong from a string: strtoll and
725        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
726        instance, but it only takes 2 args instead of 3!"
728    18. A subtle bug concerned with back references has been fixed by a change of
729        specification, with a corresponding code fix. A pattern such as
730        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
731        refers, was giving matches when it shouldn't. For example, xa=xaaa would
732        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
733        same bug. Such groups have to be quantified to be useful, or contained
734        inside another quantified group. (If there's no repetition, the reference
735        can never match.) The problem arises because, having left the group and
736        moved on to the rest of the pattern, a later failure that backtracks into
737        the group uses the captured value from the final iteration of the group
738        rather than the correct earlier one. I have fixed this in PCRE by forcing
739        any group that contains a reference to itself to be an atomic group; that
740        is, there cannot be any backtracking into it once it has completed. This is
741        similar to recursive and subroutine calls.
744    Version 8.00 19-Oct-09
745    ----------------------
747    1.  The table for translating pcre_compile() error codes into POSIX error codes
748        was out-of-date, and there was no check on the pcre_compile() error code
749        being within the table. This could lead to an OK return being given in
750        error.
752    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
753        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
754        in a Windows environment.
756    3.  The pcregrep --count option prints the count for each file even when it is
757        zero, as does GNU grep. However, pcregrep was also printing all files when
758        --files-with-matches was added. Now, when both options are given, it prints
759        counts only for those files that have at least one match. (GNU grep just
760        prints the file name in this circumstance, but including the count seems
761        more useful - otherwise, why use --count?) Also ensured that the
762        combination -clh just lists non-zero counts, with no names.
764    4.  The long form of the pcregrep -F option was incorrectly implemented as
765        --fixed_strings instead of --fixed-strings. This is an incompatible change,
766        but it seems right to fix it, and I didn't think it was worth preserving
767        the old behaviour.
769    5.  The command line items --regex=pattern and --regexp=pattern were not
770        recognized by pcregrep, which required --regex pattern or --regexp pattern
771        (with a space rather than an '='). The man page documented the '=' forms,
772        which are compatible with GNU grep; these now work.
774    6.  No libpcreposix.pc file was created for pkg-config; there was just
775        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
777    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
778        when UCP support is not needed, by modifying the Python script that
779        generates it from Unicode data files. This should not matter if the module
780        is correctly used as a library, but I received one complaint about 50K of
781        unwanted data. My guess is that the person linked everything into his
782        program rather than using a library. Anyway, it does no harm.
784    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
785        was a minimum greater than 1 for a wide character in a possessive
786        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
787        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
788        character. Chaos in the form of incorrect output or a compiling loop could
789        result.
791    9.  The restrictions on what a pattern can contain when partial matching is
792        requested for pcre_exec() have been removed. All patterns can now be
793        partially matched by this function. In addition, if there are at least two
794        slots in the offset vector, the offset of the earliest inspected character
795        for the match and the offset of the end of the subject are set in them when
796        PCRE_ERROR_PARTIAL is returned.
798    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
799        synonymous with PCRE_PARTIAL, for backwards compatibility, and
800        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
801        and may be more useful for multi-segment matching.
803    11. Partial matching with pcre_exec() is now more intuitive. A partial match
804        used to be given if ever the end of the subject was reached; now it is
805        given only if matching could not proceed because another character was
806        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
807        string "Z", which now yields "no match" instead of "partial match". In the
808        case of pcre_dfa_exec(), "no match" is given if every matching path for the
809        final character ended with (*FAIL).
811    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
812        if the pattern had a "must contain" character that was already found in the
813        earlier partial match, unless partial matching was again requested. For
814        example, with the pattern /dog.(body)?/, the "must contain" character is
815        "g". If the first part-match was for the string "dog", restarting with
816        "sbody" failed. This bug has been fixed.
818    13. The string returned by pcre_dfa_exec() after a partial match has been
819        changed so that it starts at the first inspected character rather than the
820        first character of the match. This makes a difference only if the pattern
821        starts with a lookbehind assertion or \b or \B (\K is not supported by
822        pcre_dfa_exec()). It's an incompatible change, but it makes the two
823        matching functions compatible, and I think it's the right thing to do.
825    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
826        so that the demonstration program is easily available in environments where
827        PCRE has not been installed from source.
829    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
830        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
831        library.
833    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
834        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
835        is not the first non-POSIX option to be added. Clearly some people find
836        these options useful.
838    17. If a caller to the POSIX matching function regexec() passes a non-zero
839        value for nmatch with a NULL value for pmatch, the value of
840        nmatch is forced to zero.
842    18. RunGrepTest did not have a test for the availability of the -u option of
843        the diff command, as RunTest does. It now checks in the same way as
844        RunTest, and also checks for the -b option.
846    19. If an odd number of negated classes containing just a single character
847        interposed, within parentheses, between a forward reference to a named
848        subpattern and the definition of the subpattern, compilation crashed with
849        an internal error, complaining that it could not find the referenced
850        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
851        [The bug was that it was starting one character too far in when skipping
852        over the character class, thus treating the ] as data rather than
853        terminating the class. This meant it could skip too much.]
855    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
856        /g option in pcretest when the pattern contains \K, which makes it possible
857        to have an empty string match not at the start, even when the pattern is
858        anchored. Updated pcretest and pcredemo to use this option.
860    21. If the maximum number of capturing subpatterns in a recursion was greater
861        than the maximum at the outer level, the higher number was returned, but
862        with unset values at the outer level. The correct (outer level) value is
863        now given.
865    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
866        PCRE did not set those parentheses (unlike Perl). I have now found a way to
867        make it do so. The string so far is captured, making this feature
868        compatible with Perl.
870    23. The tests have been re-organized, adding tests 11 and 12, to make it
871        possible to check the Perl 5.10 features against Perl 5.10.
873    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
874        pattern matches a fixed length string. PCRE did not allow this; now it
875        does. Neither allows recursion.
877    25. I finally figured out how to implement a request to provide the minimum
878        length of subject string that was needed in order to match a given pattern.
879        (It was back references and recursion that I had previously got hung up
880        on.) This code has now been added to pcre_study(); it finds a lower bound
881        to the length of subject needed. It is not necessarily the greatest lower
882        bound, but using it to avoid searching strings that are too short does give
883        some useful speed-ups. The value is available to calling programs via
884        pcre_fullinfo().
886    26. While implementing 25, I discovered to my embarrassment that pcretest had
887        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
888        study optimizations had never been tested with that matching function.
889        Oops. What is worse, even when it was passed study data, there was a bug in
890        pcre_dfa_exec() that meant it never actually used it. Double oops. There
891        were also very few tests of studied patterns with pcre_dfa_exec().
893    27. If (?| is used to create subpatterns with duplicate numbers, they are now
894        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
895        on the other side of the coin, they are no longer allowed to have different
896        names, because these cannot be distinguished in PCRE, and this has caused
897        confusion. (This is a difference from Perl.)
899    28. When duplicate subpattern names are present (necessarily with different
900        numbers, as required by 27 above), and a test is made by name in a
901        conditional pattern, either for a subpattern having been matched, or for
902        recursion in such a pattern, all the associated numbered subpatterns are
903        tested, and the overall condition is true if the condition is true for any
904        one of them. This is the way Perl works, and is also more like the way
905        testing by number works.
908  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
909  ---------------------  ---------------------
# Line 112  Version 7.9 11-Apr-09 Line 1016  Version 7.9 11-Apr-09
1017  26. Changed a few more instances of "const unsigned char *" to USPTR, making  26. Changed a few more instances of "const unsigned char *" to USPTR, making
1018      the feature of a custom pointer more persuasive (as requested by a user).      the feature of a custom pointer more persuasive (as requested by a user).
1020  27. Wrapped the definitions of fileno and isatty for Windows, which appear in  27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1021      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
1022      pre-defined.      pre-defined.
1024  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
1026  29. Arrange for flags added by the "release type" setting in CMake to be shown  29. Arrange for flags added by the "release type" setting in CMake to be shown
1027      in the configuration summary.      in the configuration summary.

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