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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.6 19-Jan-08  Version 8.21
5    ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
45    10. Add a cast and remove a redundant test from the code.
47    11. JIT should use pcre_malloc/pcre_free for allocation.
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". The
60        maximum number of forward references (including repeats) was limited by the
61        internal workspace, and dependent on the LINK_SIZE. The code has been
62        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
63        the default depends on LINK_SIZE. There is a new upper limit (for safety)
64        of around 200,000 forward references. While doing this, I also speeded up
65        the filling in of repeated forward references.
67    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
68        incorrectly expecting the subject to contain another "a" after the start.
70    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
71        in the match, the SKIP should be ignored. This was not happening; instead
72        the SKIP was being treated as NOMATCH. For patterns such as
73        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
74        tested.
76    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
77        now much more compatible with Perl, in particular in cases where the result
78        is a non-match for a non-anchored pattern. For example, if
79        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
80        "m", where previously it did not return a name. A side effect of this
81        change is that for partial matches, the last encountered mark name is
82        returned, as for non matches. A number of tests that were previously not
83        Perl-compatible have been moved into the Perl-compatible test files. The
84        refactoring has had the pleasing side effect of removing one argument from
85        the match() function, thus reducing its stack requirements.
87    19. If the /S+ option was used in pcretest to study a pattern using JIT,
88        subsequent uses of /S (without +) incorrectly behaved like /S+.
91    Version 8.20 21-Oct-2011
92    ------------------------
94    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
95        a POSIX class. After further experiments with Perl, which convinced me that
96        Perl has bugs and confusions, a closing square bracket is no longer allowed
97        in a POSIX name. This bug also affected patterns with classes that started
98        with full stops.
100    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
101        captured substring, but while checking the failing first alternative,
102        substring 1 is temporarily captured. If the output vector supplied to
103        pcre_exec() was not big enough for this capture, the yield of the function
104        was still zero ("insufficient space for captured substrings"). This cannot
105        be totally fixed without adding another stack variable, which seems a lot
106        of expense for a edge case. However, I have improved the situation in cases
107        such as /(a)(b)x|abc/ matched against "abc", where the return code
108        indicates that fewer than the maximum number of slots in the ovector have
109        been set.
111    3.  Related to (2) above: when there are more back references in a pattern than
112        slots in the output vector, pcre_exec() uses temporary memory during
113        matching, and copies in the captures as far as possible afterwards. It was
114        using the entire output vector, but this conflicts with the specification
115        that only 2/3 is used for passing back captured substrings. Now it uses
116        only the first 2/3, for compatibility. This is, of course, another edge
117        case.
119    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
120        main code base, and can be used by building with --enable-jit. When this is
121        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
122        runtime --no-jit option is given.
124    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
125        ovector, the return from the function was zero, implying that there were
126        other matches that did not fit. The correct "exactly full" value is now
127        returned.
129    6.  If a subpattern that was called recursively or as a subroutine contained
130        (*PRUNE) or any other control that caused it to give a non-standard return,
131        invalid errors such as "Error -26 (nested recursion at the same subject
132        position)" or even infinite loops could occur.
134    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
135        computing the minimum length on reaching *ACCEPT, and so ended up with the
136        wrong value of 1 rather than 0. Further investigation indicates that
137        computing a minimum subject length in the presence of *ACCEPT is difficult
138        (think back references, subroutine calls), and so I have changed the code
139        so that no minimum is registered for a pattern that contains *ACCEPT.
141    8.  If (*THEN) was present in the first (true) branch of a conditional group,
142        it was not handled as intended. [But see 16 below.]
144    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
145        Sheri Pierce.
147    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
148        the first byte in a match must be "a".
150    11. Change 17 for 8.13 increased the recursion depth for patterns like
151        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
152        pattern contains any instances of (*THEN). If it does not, the old
153        optimizations are restored. It would be nice to do this on a per-group
154        basis, but at the moment that is not feasible.
156    12. In some environments, the output of pcretest -C is CRLF terminated. This
157        broke RunTest's code that checks for the link size. A single white space
158        character after the value is now allowed for.
160    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
161        For "fr", it uses the Windows-specific input and output files.
163    14. If (*THEN) appeared in a group that was called recursively or as a
164        subroutine, it did not work as intended. [But see next item.]
166    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
167        pattern fragments (but not containing any | characters). If A and B are
168        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
169        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
170        D. In other words, Perl considers parentheses that do not contain any |
171        characters to be part of a surrounding alternative, whereas PCRE was
172        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
173        differently. PCRE now behaves in the same way as Perl, except in the case
174        of subroutine/recursion calls such as (?1) which have in any case always
175        been different (but PCRE had them first :-).
177    16. Related to 15 above: Perl does not treat the | in a conditional group as
178        creating alternatives. Such a group is treated in the same way as an
179        ordinary group without any | characters when processing (*THEN). PCRE has
180        been changed to match Perl's behaviour.
182    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
183        RunGrepTest script failed.
185    18. Change 22 for version 13 caused atomic groups to use more stack. This is
186        inevitable for groups that contain captures, but it can lead to a lot of
187        stack use in large patterns. The old behaviour has been restored for atomic
188        groups that do not contain any capturing parentheses.
190    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
191        suppress the check for a minimum subject length at run time. (If it was
192        given to pcre_exec() or pcre_dfa_exec() it did work.)
194    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
195        fail to work when decoding hex characters in data strings in EBCDIC
196        environments.
198    21. It appears that in at least one Mac OS environment, the isxdigit() function
199        is implemented as a macro that evaluates to its argument more than once,
200        contravening the C 90 Standard (I haven't checked a later standard). There
201        was an instance in pcretest which caused it to go wrong when processing
202        \x{...} escapes in subject strings. The has been rewritten to avoid using
203        things like p++ in the argument of isxdigit().
206    Version 8.13 16-Aug-2011
207    ------------------------
209    1.  The Unicode data tables have been updated to Unicode 6.0.0.
211    2.  Two minor typos in pcre_internal.h have been fixed.
213    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
214        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
215        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
217    4.  There were a number of related bugs in the code for matching backrefences
218        caselessly in UTF-8 mode when codes for the characters concerned were
219        different numbers of bytes. For example, U+023A and U+2C65 are an upper
220        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
221        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
222        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
223        2-byte code at the end of the subject (it thought there wasn't enough data
224        left).
226    5.  Comprehensive information about what went wrong is now returned by
227        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
228        as the output vector has at least 2 elements. The offset of the start of
229        the failing character and a reason code are placed in the vector.
231    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
232        now returned is for the first byte of the failing character, instead of the
233        last byte inspected. This is an incompatible change, but I hope it is small
234        enough not to be a problem. It makes the returned offset consistent with
235        pcre_exec() and pcre_dfa_exec().
237    7.  pcretest now gives a text phrase as well as the error number when
238        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
239        failure, the offset and reason code are output.
241    8.  When \R was used with a maximizing quantifier it failed to skip backwards
242        over a \r\n pair if the subsequent match failed. Instead, it just skipped
243        back over a single character (\n). This seems wrong (because it treated the
244        two characters as a single entity when going forwards), conflicts with the
245        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
246        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
247        has been changed.
249    9.  Some internal refactoring has changed the processing so that the handling
250        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
251        time (the PCRE_DOTALL option was changed this way some time ago: version
252        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
253        which was always a bit of a fudge. It also means that there is one less
254        argument for the match() function, which reduces its stack requirements
255        slightly. This change also fixes an incompatibility with Perl: the pattern
256        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
258    10. More internal refactoring has drastically reduced the number of recursive
259        calls to match() for possessively repeated groups such as (abc)++ when
260        using pcre_exec().
262    11. While implementing 10, a number of bugs in the handling of groups were
263        discovered and fixed:
265        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
266        (a|)*(?1) gave a compile-time internal error.
267        ((a|)+)+  did not notice that the outer group could match an empty string.
268        (^a|^)+   was not marked as anchored.
269        (.*a|.*)+ was not marked as matching at start or after a newline.
271    12. Yet more internal refactoring has removed another argument from the match()
272        function. Special calls to this function are now indicated by setting a
273        value in a variable in the "match data" data block.
275    13. Be more explicit in pcre_study() instead of relying on "default" for
276        opcodes that mean there is no starting character; this means that when new
277        ones are added and accidentally left out of pcre_study(), testing should
278        pick them up.
280    14. The -s option of pcretest has been documented for ages as being an old
281        synonym of -m (show memory usage). I have changed it to mean "force study
282        for every regex", that is, assume /S for every regex. This is similar to -i
283        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
284        using it. It makes it easier to run collections of tests with and without
285        study enabled, and thereby test pcre_study() more easily. All the standard
286        tests are now run with and without -s (but some patterns can be marked as
287        "never study" - see 20 below).
289    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
290        restoration of the capturing data to the outer values was not happening
291        correctly.
293    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
294        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
295        pattern had matched an empty string, and so incorrectly returned a no
296        match.
298    17. There was optimizing code for the last branch of non-capturing parentheses,
299        and also for the obeyed branch of a conditional subexpression, which used
300        tail recursion to cut down on stack usage. Unfortunately, now that there is
301        the possibility of (*THEN) occurring in these branches, tail recursion is
302        no longer possible because the return has to be checked for (*THEN). These
303        two optimizations have therefore been removed. [But see 8.20/11 above.]
305    18. If a pattern containing \R was studied, it was assumed that \R always
306        matched two bytes, thus causing the minimum subject length to be
307        incorrectly computed because \R can also match just one byte.
309    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
310        was incorrectly computed.
312    20. If /S is present twice on a test pattern in pcretest input, it now
313        *disables* studying, thereby overriding the use of -s on the command line
314        (see 14 above). This is necessary for one or two tests to keep the output
315        identical in both cases.
317    21. When (*ACCEPT) was used in an assertion that matched an empty string and
318        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
320    22. When an atomic group that contained a capturing parenthesis was
321        successfully matched, but the branch in which it appeared failed, the
322        capturing was not being forgotten if a higher numbered group was later
323        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
324        group 1 to "a", when in fact it should be unset. This applied to multi-
325        branched capturing and non-capturing groups, repeated or not, and also to
326        positive assertions (capturing in negative assertions does not happen
327        in PCRE) and also to nested atomic groups.
329    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
330        subject after a captured substring, to make it easier to tell which of a
331        number of identical substrings has been captured.
333    24. The way atomic groups are processed by pcre_exec() has been changed so that
334        if they are repeated, backtracking one repetition now resets captured
335        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
336        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
337        "aaa". Previously, it would have been "a". As part of this code
338        refactoring, the way recursive calls are handled has also been changed.
340    25. If an assertion condition captured any substrings, they were not passed
341        back unless some other capturing happened later. For example, if
342        (?(?=(a))a) was matched against "a", no capturing was returned.
344    26. When studying a pattern that contained subroutine calls or assertions,
345        the code for finding the minimum length of a possible match was handling
346        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
347        group 1 called group 2 while simultaneously a separate group 2 called group
348        1). A stack overflow occurred in this case. I have fixed this by limiting
349        the recursion depth to 10.
351    27. Updated RunTest.bat in the distribution to the version supplied by Tom
352        Fortmann. This supports explicit test numbers on the command line, and has
353        argument validation and error reporting.
355    28. An instance of \X with an unlimited repeat could fail if at any point the
356        first character it looked at was a mark character.
358    29. Some minor code refactoring concerning Unicode properties and scripts
359        should reduce the stack requirement of match() slightly.
361    30. Added the '=' option to pcretest to check the setting of unused capturing
362        slots at the end of the pattern, which are documented as being -1, but are
363        not included in the return count.
365    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
366        compiled something random. Now it gives a compile-time error (as does
367        Perl).
369    32. A *MARK encountered during the processing of a positive assertion is now
370        recorded and passed back (compatible with Perl).
372    33. If --only-matching or --colour was set on a pcregrep call whose pattern
373        had alternative anchored branches, the search for a second match in a line
374        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
375        matched the line "0102" twice. The same bug affected patterns that started
376        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
377        twice.
379    34. Previously, PCRE did not allow quantification of assertions. However, Perl
380        does, and because of capturing effects, quantifying parenthesized
381        assertions may at times be useful. Quantifiers are now allowed for
382        parenthesized assertions.
384    35. A minor code tidy in pcre_compile() when checking options for \R usage.
386    36. \g was being checked for fancy things in a character class, when it should
387        just be a literal "g".
389    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
390        appearance of a nested POSIX class supersedes an apparent external class.
391        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
392        unescaped square brackets may also appear as part of class names. For
393        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
394        more like Perl. (But see 8.20/1 above.)
396    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
397        was because it thought it was \N{name}, which is not supported).
399    39. Add minix to OS list not supporting the -S option in pcretest.
401    40. PCRE tries to detect cases of infinite recursion at compile time, but it
402        cannot analyze patterns in sufficient detail to catch mutual recursions
403        such as ((?1))((?2)). There is now a runtime test that gives an error if a
404        subgroup is called recursively as a subpattern for a second time at the
405        same position in the subject string. In previous releases this might have
406        been caught by the recursion limit, or it might have run out of stack.
408    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
409        happen only once. PCRE was, however incorrectly giving a compile time error
410        "recursive call could loop indefinitely" because it cannot analyze the
411        pattern in sufficient detail. The compile time test no longer happens when
412        PCRE is compiling a conditional subpattern, but actual runaway loops are
413        now caught at runtime (see 40 above).
415    42. It seems that Perl allows any characters other than a closing parenthesis
416        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
417        has been changed to be the same.
419    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
420        as not to get warnings when autogen.sh is called. Also changed
421        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
423    44. To help people who use pcregrep to scan files containing exceedingly long
424        lines, the following changes have been made:
426        (a) The default value of the buffer size parameter has been increased from
427            8K to 20K. (The actual buffer used is three times this size.)
429        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
430            PCRE is built.
432        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
433            to be set at run time.
435        (d) Numerical values in pcregrep options can be followed by K or M, for
436            example --buffer-size=50K.
438        (e) If a line being scanned overflows pcregrep's buffer, an error is now
439            given and the return code is set to 2.
441    45. Add a pointer to the latest mark to the callout data block.
443    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
444        partial match of an empty string instead of no match. This was specific to
445        the use of ".".
447    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
448        complete match instead of a partial match. This bug was dependent on both
449        the PCRE_UTF8 and PCRE_DOTALL options being set.
451    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
452        starting byte set, because \b was not being ignored.
455    Version 8.12 15-Jan-2011
456    ------------------------
458    1.  Fixed some typos in the markup of the man pages, and wrote a script that
459        checks for such things as part of the documentation building process.
461    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
462        --match-limit and --recursion-limit options (added for 8.11). In
463        particular, this made one of the standard tests fail. (The integer value
464        went into the wrong half of a long int.)
466    3.  If the --colour option was given to pcregrep with -v (invert match), it
467        did strange things, either producing crazy output, or crashing. It should,
468        of course, ignore a request for colour when reporting lines that do not
469        match.
471    4.  Another pcregrep bug caused similar problems if --colour was specified with
472        -M (multiline) and the pattern match finished with a line ending.
474    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
475        matched in multiline mode, the following line was shown as part of the
476        match. This seems wrong, so I have changed it.
478    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
479        the check for further matches in the same line (so they could be coloured)
480        to overrun the end of the current line. If another match was found, it was
481        incorrectly shown (and then shown again when found in the next line).
483    7.  If pcregrep was compiled under Windows, there was a reference to the
484        function pcregrep_exit() before it was defined. I am assuming this was
485        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
486        reported by a user. I've moved the definition above the reference.
489    Version 8.11 10-Dec-2010
490    ------------------------
492    1.  (*THEN) was not working properly if there were untried alternatives prior
493        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
494        backtracked to try for "b" instead of moving to the next alternative branch
495        at the same level (in this case, to look for "c"). The Perl documentation
496        is clear that when (*THEN) is backtracked onto, it goes to the "next
497        alternative in the innermost enclosing group".
499    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
500        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
501        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
502        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
503        (*THEN).
505    3.  If \s appeared in a character class, it removed the VT character from
506        the class, even if it had been included by some previous item, for example
507        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
508        of \s, but is part of the POSIX "space" class.)
510    4.  A partial match never returns an empty string (because you can always
511        match an empty string at the end of the subject); however the checking for
512        an empty string was starting at the "start of match" point. This has been
513        changed to the "earliest inspected character" point, because the returned
514        data for a partial match starts at this character. This means that, for
515        example, /(?<=abc)def/ gives a partial match for the subject "abc"
516        (previously it gave "no match").
518    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
519        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
520        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
521        has an implication that the given string is incomplete (because a partial
522        match is preferred over a full match). For this reason, these items now
523        give a partial match in this situation. [Aside: previously, the one case
524        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
525        match rather than a full match, which was wrong by the old rules, but is
526        now correct.]
528    6.  There was a bug in the handling of #-introduced comments, recognized when
529        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
530        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
531        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
532        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
533        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
534        places in pcre_compile().
536    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
537        comments when looking ahead for named forward references to subpatterns,
538        the only newline sequence it recognized was NL. It now handles newlines
539        according to the set newline convention.
541    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
542        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
543        cater for a lack of strerror(). These oversights have been fixed.
545    9.  Added --match-limit and --recursion-limit to pcregrep.
547    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
549    11. When the -o option was used, pcregrep was setting a return code of 1, even
550        when matches were found, and --line-buffered was not being honoured.
552    12. Added an optional parentheses number to the -o and --only-matching options
553        of pcregrep.
555    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
556        can match an empty string. The code to do it in pcretest and pcredemo
557        needed fixing:
559        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
560            only one byte after an empty string match just before CRLF (this case
561            just got forgotten; "any" and "anycrlf" were OK).
563        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
564            mode when an empty string match preceded an ASCII character followed by
565            a non-ASCII character. (The code for advancing by one character rather
566            than one byte was nonsense.)
568        (c) The pcredemo.c sample program did not have any code at all to handle
569            the cases when CRLF is a valid newline sequence.
571    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
572        as a starting offset was within the subject string. There is now a new
573        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
574        negative or greater than the length of the string. In order to test this,
575        pcretest is extended to allow the setting of negative starting offsets.
577    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
578        starting offset points to the beginning of a UTF-8 character was
579        unnecessarily clumsy. I tidied it up.
581    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
582        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
584    17. Nobody had reported that the --include_dir option, which was added in
585        release 7.7 should have been called --include-dir (hyphen, not underscore)
586        for compatibility with GNU grep. I have changed it to --include-dir, but
587        left --include_dir as an undocumented synonym, and the same for
588        --exclude-dir, though that is not available in GNU grep, at least as of
589        release 2.5.4.
591    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
592        characters from a string of bytes) have been redefined so as not to use
593        loops, in order to improve performance in some environments. At the same
594        time, I abstracted some of the common code into auxiliary macros to save
595        repetition (this should not affect the compiled code).
597    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
598        compile-time error is now given if \c is not followed by an ASCII
599        character, that is, a byte less than 128. (In EBCDIC mode, the code is
600        different, and any byte value is allowed.)
602    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
603        START_OPTIMIZE option, which is now allowed at compile time - but just
604        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
605        to pcregrep and other applications that have no direct access to PCRE
606        options. The new /Y option in pcretest sets this option when calling
607        pcre_compile().
609    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
610        back references. Groups containing recursive back references were forced to
611        be atomic by that change, but in the case of named groups, the amount of
612        memory required was incorrectly computed, leading to "Failed: internal
613        error: code overflow". This has been fixed.
615    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
616        pcretest.c, to avoid build problems in some Borland environments.
619    Version 8.10 25-Jun-2010
620    ------------------------
622    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
623        THEN.
625    2.  (*ACCEPT) was not working when inside an atomic group.
627    3.  Inside a character class, \B is treated as a literal by default, but
628        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
629        causes the error). The code is unchanged, but I tidied the documentation.
631    4.  Inside a character class, PCRE always treated \R and \X as literals,
632        whereas Perl faults them if its -w option is set. I have changed PCRE so
633        that it faults them when PCRE_EXTRA is set.
635    5.  Added support for \N, which always matches any character other than
636        newline. (It is the same as "." when PCRE_DOTALL is not set.)
638    6.  When compiling pcregrep with newer versions of gcc which may have
639        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
640        declared with attribute warn_unused_result" were given. Just casting the
641        result to (void) does not stop the warnings; a more elaborate fudge is
642        needed. I've used a macro to implement this.
644    7.  Minor change to pcretest.c to avoid a compiler warning.
646    8.  Added four artifical Unicode properties to help with an option to make
647        \s etc use properties (see next item). The new properties are: Xan
648        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
650    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
651        use Unicode properties. (*UCP) at the start of a pattern can be used to set
652        this option. Modified pcretest to add /W to test this facility. Added
653        REG_UCP to make it available via the POSIX interface.
655    10. Added --line-buffered to pcregrep.
657    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
658        studied, and the match started with a letter with a code point greater than
659        127 whose first byte was different to the first byte of the other case of
660        the letter, the other case of this starting letter was not recognized
661        (#976).
663    12. If a pattern that was studied started with a repeated Unicode property
664        test, for example, \p{Nd}+, there was the theoretical possibility of
665        setting up an incorrect bitmap of starting bytes, but fortunately it could
666        not have actually happened in practice until change 8 above was made (it
667        added property types that matched character-matching opcodes).
669    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
670        possible starting bytes for non-anchored patterns.
672    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
673        \R, and also a number of cases that involve Unicode properties, both
674        explicit and implicit when PCRE_UCP is set.
676    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
677        input, it could crash or give wrong results if characters with values
678        greater than 0xc0 were present in the subject string. (Detail: it assumed
679        UTF-8 input when processing these items.)
681    16. Added a lot of (int) casts to avoid compiler warnings in systems where
682        size_t is 64-bit (#991).
684    17. Added a check for running out of memory when PCRE is compiled with
685        --disable-stack-for-recursion (#990).
687    18. If the last data line in a file for pcretest does not have a newline on
688        the end, a newline was missing in the output.
690    19. The default pcre_chartables.c file recognizes only ASCII characters (values
691        less than 128) in its various bitmaps. However, there is a facility for
692        generating tables according to the current locale when PCRE is compiled. It
693        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
694        characters, are recognized by isspace() and therefore were getting set in
695        these tables, and indeed these tables seem to approximate to ISO 8859. This
696        caused a problem in UTF-8 mode when pcre_study() was used to create a list
697        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
698        which of course cannot start UTF-8 characters. I have changed the code so
699        that only real ASCII characters (less than 128) and the correct starting
700        bytes for UTF-8 encodings are set for characters greater than 127 when in
701        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
702        altogether.)
704    20. Added the /T option to pcretest so as to be able to run tests with non-
705        standard character tables, thus making it possible to include the tests
706        used for 19 above in the standard set of tests.
708    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
709        reference to a subpattern the other side of a comment that contains an
710        opening parenthesis caused either an internal compiling error, or a
711        reference to the wrong subpattern.
714    Version 8.02 19-Mar-2010
715    ------------------------
717    1.  The Unicode data tables have been updated to Unicode 5.2.0.
719    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
720        configured.
722    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
723        original author of that file, following a query about its status.
725    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
726        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
728    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
729        quantifier applied to a forward-referencing subroutine call, could compile
730        incorrect code or give the error "internal error: previously-checked
731        referenced subpattern not found".
733    6.  Both MS Visual Studio and Symbian OS have problems with initializing
734        variables to point to external functions. For these systems, therefore,
735        pcre_malloc etc. are now initialized to local functions that call the
736        relevant global functions.
738    7.  There were two entries missing in the vectors called coptable and poptable
739        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
740        I've fixed the data, and added a kludgy way of testing at compile time that
741        the lengths are correct (equal to the number of opcodes).
743    8.  Following on from 7, I added a similar kludge to check the length of the
744        eint vector in pcreposix.c.
746    9.  Error texts for pcre_compile() are held as one long string to avoid too
747        much relocation at load time. To find a text, the string is searched,
748        counting zeros. There was no check for running off the end of the string,
749        which could happen if a new error number was added without updating the
750        string.
752    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
754    11. \K was not working if it appeared in an atomic group or in a group that
755        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
756        \K is "not well defined" if used in an assertion. PCRE now accepts it if
757        the assertion is positive, but not if it is negative.
759    12. Change 11 fortuitously reduced the size of the stack frame used in the
760        "match()" function of pcre_exec.c by one pointer. Forthcoming
761        implementation of support for (*MARK) will need an extra pointer on the
762        stack; I have reserved it now, so that the stack frame size does not
763        decrease.
765    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
766        item in branch that calls a recursion is a subroutine call - as in the
767        second branch in the above example - was incorrectly given the compile-
768        time error "recursive call could loop indefinitely" because pcre_compile()
769        was not correctly checking the subroutine for matching a non-empty string.
771    14. The checks for overrunning compiling workspace could trigger after an
772        overrun had occurred. This is a "should never occur" error, but it can be
773        triggered by pathological patterns such as hundreds of nested parentheses.
774        The checks now trigger 100 bytes before the end of the workspace.
776    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
779    Version 8.01 19-Jan-2010
780    ------------------------
782    1.  If a pattern contained a conditional subpattern with only one branch (in
783        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
784        computed the wrong minimum data length (which is of course zero for such
785        subpatterns). This could cause incorrect "no match" results.
787    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
788        the pattern is reset in the first branch, pcre_compile() failed with
789        "internal error: code overflow at offset...". This happened only when
790        the reset was to the original external option setting. (An optimization
791        abstracts leading options settings into an external setting, which was the
792        cause of this.)
794    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
795        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
796        assertion pattern did not match (meaning that the assertion was true), it
797        was incorrectly treated as false if the SKIP had been reached during the
798        matching. This also applied to assertions used as conditions.
800    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
801        assertion subpattern, including such a pattern used as a condition,
802        unpredictable results occurred, instead of the error return
805    5.  The C++ GlobalReplace function was not working like Perl for the special
806        situation when an empty string is matched. It now does the fancy magic
807        stuff that is necessary.
809    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
810        removed. (These were left over from very, very early versions of PCRE.)
812    7.  Some cosmetic changes to the code to make life easier when compiling it
813        as part of something else:
815        (a) Change DEBUG to PCRE_DEBUG.
817        (b) In pcre_compile(), rename the member of the "branch_chain" structure
818            called "current" as "current_branch", to prevent a collision with the
819            Linux macro when compiled as a kernel module.
821        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
822            prevent a collision with the Linux macro when compiled as a kernel
823            module.
825    8.  In pcre_compile() there are some checks for integer overflows that used to
826        cast potentially large values to (double). This has been changed to that
827        when building, a check for int64_t is made, and if it is found, it is used
828        instead, thus avoiding the use of floating point arithmetic. (There is no
829        other use of FP in PCRE.) If int64_t is not found, the fallback is to
830        double.
832    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
833        2005 (difference between two addresses compared to an unsigned value).
835    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
836        custom one, because of the following reported problem in Windows:
838          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
839              under Win32.
840          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
841              therefore missing the function definition.
842          - The compiler thus generates a "C" signature for the test function.
843          - The linker fails to find the "C" function.
844          - PCRE fails to configure if asked to do so against libbz2.
846    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
847        messages were output:
849          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
850          rerunning libtoolize, to keep the correct libtool macros in-tree.
851          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
853        I have done both of these things.
855    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
856        most of the time, it *can* run out if it is given a pattern that contains a
857        runaway infinite recursion. I updated the discussion in the pcrestack man
858        page.
860    13. Now that we have gone to the x.xx style of version numbers, the minor
861        version may start with zero. Using 08 or 09 is a bad idea because users
862        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
863        interpreted as invalid octal numbers. I've updated the previous comment in
864        configure.ac, and also added a check that gives an error if 08 or 09 are
865        used.
867    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
868        causing partial matching to fail when the end of the subject matched \W
869        in a UTF-8 pattern where \W was quantified with a minimum of 3.
871    15. There were some discrepancies between the declarations in pcre_internal.h
872        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
873        their definitions. The declarations used "const uschar *" and the
874        definitions used USPTR. Even though USPTR is normally defined as "const
875        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
876        reported that: "This difference in casting confuses some C++ compilers, for
877        example, SunCC recognizes above declarations as different functions and
878        generates broken code for hbpcre." I have changed the declarations to use
879        USPTR.
881    16. GNU libtool is named differently on some systems. The autogen.sh script now
882        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
883        (FreeBSD).
885    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
886        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
887        comment: "Figure out how to create a longlong from a string: strtoll and
888        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
889        instance, but it only takes 2 args instead of 3!"
891    18. A subtle bug concerned with back references has been fixed by a change of
892        specification, with a corresponding code fix. A pattern such as
893        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
894        refers, was giving matches when it shouldn't. For example, xa=xaaa would
895        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
896        same bug. Such groups have to be quantified to be useful, or contained
897        inside another quantified group. (If there's no repetition, the reference
898        can never match.) The problem arises because, having left the group and
899        moved on to the rest of the pattern, a later failure that backtracks into
900        the group uses the captured value from the final iteration of the group
901        rather than the correct earlier one. I have fixed this in PCRE by forcing
902        any group that contains a reference to itself to be an atomic group; that
903        is, there cannot be any backtracking into it once it has completed. This is
904        similar to recursive and subroutine calls.
907    Version 8.00 19-Oct-09
908    ----------------------
910    1.  The table for translating pcre_compile() error codes into POSIX error codes
911        was out-of-date, and there was no check on the pcre_compile() error code
912        being within the table. This could lead to an OK return being given in
913        error.
915    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
916        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
917        in a Windows environment.
919    3.  The pcregrep --count option prints the count for each file even when it is
920        zero, as does GNU grep. However, pcregrep was also printing all files when
921        --files-with-matches was added. Now, when both options are given, it prints
922        counts only for those files that have at least one match. (GNU grep just
923        prints the file name in this circumstance, but including the count seems
924        more useful - otherwise, why use --count?) Also ensured that the
925        combination -clh just lists non-zero counts, with no names.
927    4.  The long form of the pcregrep -F option was incorrectly implemented as
928        --fixed_strings instead of --fixed-strings. This is an incompatible change,
929        but it seems right to fix it, and I didn't think it was worth preserving
930        the old behaviour.
932    5.  The command line items --regex=pattern and --regexp=pattern were not
933        recognized by pcregrep, which required --regex pattern or --regexp pattern
934        (with a space rather than an '='). The man page documented the '=' forms,
935        which are compatible with GNU grep; these now work.
937    6.  No libpcreposix.pc file was created for pkg-config; there was just
938        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
940    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
941        when UCP support is not needed, by modifying the Python script that
942        generates it from Unicode data files. This should not matter if the module
943        is correctly used as a library, but I received one complaint about 50K of
944        unwanted data. My guess is that the person linked everything into his
945        program rather than using a library. Anyway, it does no harm.
947    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
948        was a minimum greater than 1 for a wide character in a possessive
949        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
950        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
951        character. Chaos in the form of incorrect output or a compiling loop could
952        result.
954    9.  The restrictions on what a pattern can contain when partial matching is
955        requested for pcre_exec() have been removed. All patterns can now be
956        partially matched by this function. In addition, if there are at least two
957        slots in the offset vector, the offset of the earliest inspected character
958        for the match and the offset of the end of the subject are set in them when
959        PCRE_ERROR_PARTIAL is returned.
961    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
962        synonymous with PCRE_PARTIAL, for backwards compatibility, and
963        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
964        and may be more useful for multi-segment matching.
966    11. Partial matching with pcre_exec() is now more intuitive. A partial match
967        used to be given if ever the end of the subject was reached; now it is
968        given only if matching could not proceed because another character was
969        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
970        string "Z", which now yields "no match" instead of "partial match". In the
971        case of pcre_dfa_exec(), "no match" is given if every matching path for the
972        final character ended with (*FAIL).
974    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
975        if the pattern had a "must contain" character that was already found in the
976        earlier partial match, unless partial matching was again requested. For
977        example, with the pattern /dog.(body)?/, the "must contain" character is
978        "g". If the first part-match was for the string "dog", restarting with
979        "sbody" failed. This bug has been fixed.
981    13. The string returned by pcre_dfa_exec() after a partial match has been
982        changed so that it starts at the first inspected character rather than the
983        first character of the match. This makes a difference only if the pattern
984        starts with a lookbehind assertion or \b or \B (\K is not supported by
985        pcre_dfa_exec()). It's an incompatible change, but it makes the two
986        matching functions compatible, and I think it's the right thing to do.
988    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
989        so that the demonstration program is easily available in environments where
990        PCRE has not been installed from source.
992    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
993        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
994        library.
996    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
997        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
998        is not the first non-POSIX option to be added. Clearly some people find
999        these options useful.
1001    17. If a caller to the POSIX matching function regexec() passes a non-zero
1002        value for nmatch with a NULL value for pmatch, the value of
1003        nmatch is forced to zero.
1005    18. RunGrepTest did not have a test for the availability of the -u option of
1006        the diff command, as RunTest does. It now checks in the same way as
1007        RunTest, and also checks for the -b option.
1009    19. If an odd number of negated classes containing just a single character
1010        interposed, within parentheses, between a forward reference to a named
1011        subpattern and the definition of the subpattern, compilation crashed with
1012        an internal error, complaining that it could not find the referenced
1013        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1014        [The bug was that it was starting one character too far in when skipping
1015        over the character class, thus treating the ] as data rather than
1016        terminating the class. This meant it could skip too much.]
1018    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1019        /g option in pcretest when the pattern contains \K, which makes it possible
1020        to have an empty string match not at the start, even when the pattern is
1021        anchored. Updated pcretest and pcredemo to use this option.
1023    21. If the maximum number of capturing subpatterns in a recursion was greater
1024        than the maximum at the outer level, the higher number was returned, but
1025        with unset values at the outer level. The correct (outer level) value is
1026        now given.
1028    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1029        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1030        make it do so. The string so far is captured, making this feature
1031        compatible with Perl.
1033    23. The tests have been re-organized, adding tests 11 and 12, to make it
1034        possible to check the Perl 5.10 features against Perl 5.10.
1036    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1037        pattern matches a fixed length string. PCRE did not allow this; now it
1038        does. Neither allows recursion.
1040    25. I finally figured out how to implement a request to provide the minimum
1041        length of subject string that was needed in order to match a given pattern.
1042        (It was back references and recursion that I had previously got hung up
1043        on.) This code has now been added to pcre_study(); it finds a lower bound
1044        to the length of subject needed. It is not necessarily the greatest lower
1045        bound, but using it to avoid searching strings that are too short does give
1046        some useful speed-ups. The value is available to calling programs via
1047        pcre_fullinfo().
1049    26. While implementing 25, I discovered to my embarrassment that pcretest had
1050        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1051        study optimizations had never been tested with that matching function.
1052        Oops. What is worse, even when it was passed study data, there was a bug in
1053        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1054        were also very few tests of studied patterns with pcre_dfa_exec().
1056    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1057        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1058        on the other side of the coin, they are no longer allowed to have different
1059        names, because these cannot be distinguished in PCRE, and this has caused
1060        confusion. (This is a difference from Perl.)
1062    28. When duplicate subpattern names are present (necessarily with different
1063        numbers, as required by 27 above), and a test is made by name in a
1064        conditional pattern, either for a subpattern having been matched, or for
1065        recursion in such a pattern, all the associated numbered subpatterns are
1066        tested, and the overall condition is true if the condition is true for any
1067        one of them. This is the way Perl works, and is also more like the way
1068        testing by number works.
1071    Version 7.9 11-Apr-09
1072    ---------------------
1074    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1075        (pcretest), all targets were linked against these libraries. This included
1076        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1077        libraries. This caused unwanted dependencies to be created. This problem
1078        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1079        pcretest is linked with readline.
1081    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1082        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1083        moved outside it again, because FALSE and TRUE are already defined in AIX,
1084        but BOOL is not.
1086    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1087        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1089    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1090        hyphens) following file names and line numbers when outputting matching
1091        lines. This is not true; no spaces are inserted. I have also clarified the
1092        wording for the --colour (or --color) option.
1094    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1095        was not coloured; this is different to GNU grep, so I have changed it to be
1096        the same.
1098    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1099        each matching line was coloured. Now it goes on to look for further matches
1100        of any of the test patterns, which is the same behaviour as GNU grep.
1102    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1103        doesn't make sense to accept an empty string match in pcregrep, so I have
1104        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1105        seems to be how GNU grep behaves.
1107    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1108        start or after a newline", because the conditional assertion was not being
1109        correctly handled. The rule now is that both the assertion and what follows
1110        in the first alternative must satisfy the test.
1112    9.  If auto-callout was enabled in a pattern with a conditional group whose
1113        condition was an assertion, PCRE could crash during matching, both with
1114        pcre_exec() and pcre_dfa_exec().
1116    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1117        used for matching.
1119    11. Unicode property support in character classes was not working for
1120        characters (bytes) greater than 127 when not in UTF-8 mode.
1122    12. Added the -M command line option to pcretest.
1124    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1126    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1128    16. Added comments and documentation about mis-use of no_arg in the C++
1129        wrapper.
1131    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1132        from Martin Jerabek that uses macro names for all relevant character and
1133        string constants.
1135    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1136        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1137        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1138        these, but not everybody uses configure.
1140    19. A conditional group that had only one branch was not being correctly
1141        recognized as an item that could match an empty string. This meant that an
1142        enclosing group might also not be so recognized, causing infinite looping
1143        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1144        with the subject "ab", where knowledge that the repeated group can match
1145        nothing is needed in order to break the loop.
1147    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1148        exec(), but without supplying a callout function, matching went wrong.
1150    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1151        leak if the size of the offset vector was greater than 30. When the vector
1152        is smaller, the saved offsets during recursion go onto a local stack
1153        vector, but for larger vectors malloc() is used. It was failing to free
1154        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1155        error, in fact).
1157    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1158        heapframe that is used only when UTF-8 support is enabled. This caused no
1159        problem, but was untidy.
1161    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1162        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1163        included within another project.
1165    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1166        slightly modified by me:
1168          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1169              not building pcregrep.
1171          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1172              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1174    25. Forward references, both numeric and by name, in patterns that made use of
1175        duplicate group numbers, could behave incorrectly or give incorrect errors,
1176        because when scanning forward to find the reference group, PCRE was not
1177        taking into account the duplicate group numbers. A pattern such as
1178        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1180    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1181        the feature of a custom pointer more persuasive (as requested by a user).
1183    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1184        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1185        pre-defined.
1187    28. Added support for (*UTF8) at the start of a pattern.
1189    29. Arrange for flags added by the "release type" setting in CMake to be shown
1190        in the configuration summary.
1193    Version 7.8 05-Sep-08
1194    ---------------------
1196    1.  Replaced UCP searching code with optimized version as implemented for Ad
1197        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1198        stage table and inline lookup instead of a function, giving speed ups of 2
1199        to 5 times on some simple patterns that I tested. Permission was given to
1200        distribute the MultiStage2.py script that generates the tables (it's not in
1201        the tarball, but is in the Subversion repository).
1203    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1204        scripts.
1206    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1207        a group with a zero qualifier. The result of the study could be incorrect,
1208        or the function might crash, depending on the pattern.
1210    4.  Caseless matching was not working for non-ASCII characters in back
1211        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1212        It now works when Unicode Property Support is available.
1214    5.  In pcretest, an escape such as \x{de} in the data was always generating
1215        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1216        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1217        truncation.
1219    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1221    7.  Added two (int) casts to pcregrep when printing the difference of two
1222        pointers, in case they are 64-bit values.
1224    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1225        test 2 if it fails.
1227    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1228        and a #define of that name to empty if it is not externally set. This is to
1229        allow users of MSVC to set it if necessary.
1231    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1232        the convenience functions in the pcre_get.c source file.
1234    11. An option change at the start of a pattern that had top-level alternatives
1235        could cause overwriting and/or a crash. This command provoked a crash in
1236        some environments:
1238          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1240        This potential security problem was recorded as CVE-2008-2371.
1242    12. For a pattern where the match had to start at the beginning or immediately
1243        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1244        pcre_dfa_exec() could read past the end of the passed subject if there was
1245        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1246        pcretest so that it places the subject at the end of its malloc-ed buffer.
1248    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1249        exec() might read past the end of the data buffer in UTF-8 mode.
1251    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1252        the data contained the byte 0x85 as part of a UTF-8 character within its
1253        first line. This applied both to normal and DFA matching.
1255    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1256        /^[^d]*?$/8 failed to match "abc".
1258    16. Added a missing copyright notice to pcrecpp_internal.h.
1260    17. Make it more clear in the documentation that values returned from
1261        pcre_exec() in ovector are byte offsets, not character counts.
1263    18. Tidied a few places to stop certain compilers from issuing warnings.
1265    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1266        supplied by Stefan Weber. I made a further small update for 7.8 because
1267        there is a change of source arrangements: the pcre_searchfuncs.c module is
1268        replaced by pcre_ucd.c.
1271    Version 7.7 07-May-08
1272    ---------------------
1274    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1275        a string to a long long, pretend we don't even have a long long." This is
1276        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1278    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1279        pre-7.6 versions, which defined a global no_arg variable instead of putting
1280        it in the RE class. (See also #8 below.)
1282    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1283        Lopes.
1285    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1287        (1) The include/exclude patterns were being applied to the whole pathnames
1288            of files, instead of just to the final components.
1290        (2) If there was more than one level of directory, the subdirectories were
1291            skipped unless they satisfied the include/exclude conditions. This is
1292            inconsistent with GNU grep (and could even be seen as contrary to the
1293            pcregrep specification - which I improved to make it absolutely clear).
1294            The action now is always to scan all levels of directory, and just
1295            apply the include/exclude patterns to regular files.
1297    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1298        --exclude_dir in the tests to avoid scanning .svn directories.
1300    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1301        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1302        doesn't support NULs in patterns.
1304    7.  Added some missing "const"s to declarations of static tables in
1305        pcre_compile.c and pcre_dfa_exec.c.
1307    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1308        caused by fix #2  above. (Subsequently also a second patch to fix the
1309        first patch. And a third patch - this was a messy problem.)
1311    9.  Applied Craig's patch to remove the use of push_back().
1313    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1314        matching function regexec().
1316    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1317        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1318        references. PCRE supports relative numbers with this syntax (I don't think
1319        Oniguruma does).
1321    12. Previously, a group with a zero repeat such as (...){0} was completely
1322        omitted from the compiled regex. However, this means that if the group
1323        was called as a subroutine from elsewhere in the pattern, things went wrong
1324        (an internal error was given). Such groups are now left in the compiled
1325        pattern, with a new opcode that causes them to be skipped at execution
1326        time.
1328    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1329        to the way PCRE behaves:
1331        (a) A lone ] character is dis-allowed (Perl treats it as data).
1333        (b) A back reference to an unmatched subpattern matches an empty string
1334            (Perl fails the current match path).
1336        (c) A data ] in a character class must be notated as \] because if the
1337            first data character in a class is ], it defines an empty class. (In
1338            Perl it is not possible to have an empty class.) The empty class []
1339            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1340            The negative empty class [^] matches any one character, independently
1341            of the DOTALL setting.
1343    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1344        non-existent subpattern following a character class starting with ']' and
1345        containing () gave an internal compiling error instead of "reference to
1346        non-existent subpattern". Fortunately, when the pattern did exist, the
1347        compiled code was correct. (When scanning forwards to check for the
1348        existencd of the subpattern, it was treating the data ']' as terminating
1349        the class, so got the count wrong. When actually compiling, the reference
1350        was subsequently set up correctly.)
1352    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1353        it was being rejected as not supported by pcre_dfa_exec(), even though
1354        other assertions are supported. I have made pcre_dfa_exec() support
1355        (*FAIL).
1357    16. The implementation of 13c above involved the invention of a new opcode,
1358        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1359        cannot be changed at match time, I realized I could make a small
1360        improvement to matching performance by compiling OP_ALLANY instead of
1361        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1362        on the OP_ANY path.
1364    17. Compiling pcretest on Windows with readline support failed without the
1365        following two fixes: (1) Make the unistd.h include conditional on
1366        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1368    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1369        ncurses library to be included for pcretest when ReadLine support is
1370        requested, but also to allow for it to be overridden. This patch came from
1371        Daniel Bergström.
1373    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1374        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1375        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1376        spotting this.
1379    Version 7.6 28-Jan-08
1380  ---------------------  ---------------------
1382  1.  A character class containing a very large number of characters with  1.  A character class containing a very large number of characters with
1383      codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer      codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1384      overflow.      overflow.
1386  2.  Patch to cut out the "long long" test in pcrecpp_unittest when  2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1387      HAVE_LONG_LONG is not defined.      HAVE_LONG_LONG is not defined.
1389  3.  Applied Christian Ehrlicher's patch to update the CMake build files to  3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1390      bring them up to date and include new features. This patch includes:      bring them up to date and include new features. This patch includes:
1392      - Fixed PH's badly added libz and libbz2 support.      - Fixed PH's badly added libz and libbz2 support.
1393      - Fixed a problem with static linking.      - Fixed a problem with static linking.
1394      - Added pcredemo.      - Added pcredemo. [But later removed - see 7 below.]
1395      - Fixed dftables problem and added an option.      - Fixed dftables problem and added an option.
1396      - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and      - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1397          HAVE_LONG_LONG.          HAVE_LONG_LONG.
1398      - Added readline support for pcretest.      - Added readline support for pcretest.
1399      - Added an listing of the option settings after cmake has run.      - Added an listing of the option settings after cmake has run.
1401    4.  A user submitted a patch to Makefile that makes it easy to create
1402        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1403        Makefile.am that cause it to include this special target, without
1404        affecting anything else. Note that the same mingw target plus all
1405        the other distribution libraries and programs are now supported
1406        when configuring with CMake (see 6 below) instead of with
1407        Configure/Make.
1409    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1410        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1411        exported in the Windows port". It has not yet been confirmed that the patch
1412        solves the problem, but it does no harm.
1414    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1415        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1416        with CMake, and also correct the comment about stack recursion.
1418    7.  Remove the automatic building of pcredemo from the ./configure system and
1419        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1420        of a program that users should build themselves after PCRE is installed, so
1421        building it automatically is not really right. What is more, it gave
1422        trouble in some build environments.
1424    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1427  Version 7.5 10-Jan-08  Version 7.5 10-Jan-08
1428  ---------------------  ---------------------

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