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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.13 02-Aug-2011
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
9    2.  Two minor typos in pcre_internal.h have been fixed.
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, now that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
110    20. If /S is present twice on a test pattern in pcretest input, it now
111        *disables* studying, thereby overriding the use of -s on the command line
112        (see 14 above). This is necessary for one or two tests to keep the output
113        identical in both cases.
115    21. When (*ACCEPT) was used in an assertion that matched an empty string and
116        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
118    22. When an atomic group that contained a capturing parenthesis was
119        successfully matched, but the branch in which it appeared failed, the
120        capturing was not being forgotten if a higher numbered group was later
121        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
122        group 1 to "a", when in fact it should be unset. This applied to multi-
123        branched capturing and non-capturing groups, repeated or not, and also to
124        positive assertions (capturing in negative assertions does not happen
125        in PCRE) and also to nested atomic groups.
127    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
128        subject after a captured substring, to make it easier to tell which of a
129        number of identical substrings has been captured.
131    24. The way atomic groups are processed by pcre_exec() has been changed so that
132        if they are repeated, backtracking one repetition now resets captured
133        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
134        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
135        "aaa". Previously, it would have been "a". As part of this code
136        refactoring, the way recursive calls are handled has also been changed.
138    25. If an assertion condition captured any substrings, they were not passed
139        back unless some other capturing happened later. For example, if
140        (?(?=(a))a) was matched against "a", no capturing was returned.
142    26. When studying a pattern that contained subroutine calls or assertions,
143        the code for finding the minimum length of a possible match was handling
144        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
145        group 1 called group 2 while simultaneously a separate group 2 called group
146        1). A stack overflow occurred in this case. I have fixed this by limiting
147        the recursion depth to 10.
149    27. Updated RunTest.bat in the distribution to the version supplied by Tom
150        Fortmann. This supports explicit test numbers on the command line, and has
151        argument validation and error reporting.
153    28. An instance of \X with an unlimited repeat could fail if at any point the
154        first character it looked at was a mark character.
156    29. Some minor code refactoring concerning Unicode properties and scripts
157        should reduce the stack requirement of match() slightly.
159    30. Added the '=' option to pcretest to check the setting of unused capturing
160        slots at the end of the pattern, which are documented as being -1, but are
161        not included in the return count.
163    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
164        compiled something random. Now it gives a compile-time error (as does
165        Perl).
167    32. A *MARK encountered during the processing of a positive assertion is now
168        recorded and passed back (compatible with Perl).
170    33. If --only-matching or --colour was set on a pcregrep call whose pattern
171        had alternative anchored branches, the search for a second match in a line
172        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
173        matched the line "0102" twice. The same bug affected patterns that started
174        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
175        twice.
177    34. Previously, PCRE did not allow quantification of assertions. However, Perl
178        does, and because of capturing effects, quantifying parenthesized
179        assertions may at times be useful. Quantifiers are now allowed for
180        parenthesized assertions.
182    35. A minor code tidy in pcre_compile() when checking options for \R usage.
184    36. \g was being checked for fancy things in a character class, when it should
185        just be a literal "g".
187    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
188        appearance of a nested POSIX class supersedes an apparent external class.
189        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
190        unescaped square brackets may also appear as part of class names. For
191        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
192        more like Perl.
194    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
195        was because it thought it was \N{name}, which is not supported).
197    39. Add minix to OS list not supporting the -S option in pcretest.
199    40. PCRE tries to detect cases of infinite recursion at compile time, but it
200        cannot analyze patterns in sufficient detail to catch mutual recursions
201        such as ((?1))((?2)). There is now a runtime test that gives an error if a
202        subgroup is called recursively as a subpattern for a second time at the
203        same position in the subject string. In previous releases this might have
204        been caught by the recursion limit, or it might have run out of stack.
206    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
207        happen only once. PCRE was, however incorrectly giving a compile time error
208        "recursive call could loop indefinitely" because it cannot analyze the
209        pattern in sufficient detail. The compile time test no longer happens when
210        PCRE is compiling a conditional subpattern, but actual runaway loops are
211        now caught at runtime (see 40 above).
213    42. It seems that Perl allows any characters other than a closing parenthesis
214        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
215        has been changed to be the same.
217    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
218        as not to get warnings when autogen.sh is called. Also changed
219        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
221    44. To help people who use pcregrep to scan files containing exceedingly long
222        lines, the following changes have been made:
224        (a) The default value of the buffer size parameter has been increased from
225            8K to 20K. (The actual buffer used is three times this size.)
227        (b) The default can be changed by ./configure --with-pcregrep-bufsiz when
228            PCRE is built.
230        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
231            to be set at run time.
233        (d) Numerical values in pcregrep options can be followed by K or M, for
234            example --buffer-size=50K.
236        (e) If a line being scanned overflows pcregrep's buffer, an error is now
237            given and the return code is set to 2.
239    45. Add a pointer to the latest mark to the callout data block.
241    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
242        partial match of an empty string instead of no match. This was specific to
243        the use of ".".
245    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
246        complete match instead of a partial match. This bug was dependent on both
247        the PCRE_UTF8 and PCRE_DOTALL options being set.
249    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
250        starting byte set, because \b was not being ignored.
253    Version 8.12 15-Jan-2011
254    ------------------------
256    1.  Fixed some typos in the markup of the man pages, and wrote a script that
257        checks for such things as part of the documentation building process.
259    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
260        --match-limit and --recursion-limit options (added for 8.11). In
261        particular, this made one of the standard tests fail. (The integer value
262        went into the wrong half of a long int.)
264    3.  If the --colour option was given to pcregrep with -v (invert match), it
265        did strange things, either producing crazy output, or crashing. It should,
266        of course, ignore a request for colour when reporting lines that do not
267        match.
269    4.  Another pcregrep bug caused similar problems if --colour was specified with
270        -M (multiline) and the pattern match finished with a line ending.
272    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
273        matched in multiline mode, the following line was shown as part of the
274        match. This seems wrong, so I have changed it.
276    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
277        the check for further matches in the same line (so they could be coloured)
278        to overrun the end of the current line. If another match was found, it was
279        incorrectly shown (and then shown again when found in the next line).
281    7.  If pcregrep was compiled under Windows, there was a reference to the
282        function pcregrep_exit() before it was defined. I am assuming this was
283        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
284        reported by a user. I've moved the definition above the reference.
287    Version 8.11 10-Dec-2010
288    ------------------------
290    1.  (*THEN) was not working properly if there were untried alternatives prior
291        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
292        backtracked to try for "b" instead of moving to the next alternative branch
293        at the same level (in this case, to look for "c"). The Perl documentation
294        is clear that when (*THEN) is backtracked onto, it goes to the "next
295        alternative in the innermost enclosing group".
297    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
298        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
299        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
300        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
301        (*THEN).
303    3.  If \s appeared in a character class, it removed the VT character from
304        the class, even if it had been included by some previous item, for example
305        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
306        of \s, but is part of the POSIX "space" class.)
308    4.  A partial match never returns an empty string (because you can always
309        match an empty string at the end of the subject); however the checking for
310        an empty string was starting at the "start of match" point. This has been
311        changed to the "earliest inspected character" point, because the returned
312        data for a partial match starts at this character. This means that, for
313        example, /(?<=abc)def/ gives a partial match for the subject "abc"
314        (previously it gave "no match").
316    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
317        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
318        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
319        has an implication that the given string is incomplete (because a partial
320        match is preferred over a full match). For this reason, these items now
321        give a partial match in this situation. [Aside: previously, the one case
322        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
323        match rather than a full match, which was wrong by the old rules, but is
324        now correct.]
326    6.  There was a bug in the handling of #-introduced comments, recognized when
327        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
328        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
329        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
330        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
331        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
332        places in pcre_compile().
334    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
335        comments when looking ahead for named forward references to subpatterns,
336        the only newline sequence it recognized was NL. It now handles newlines
337        according to the set newline convention.
339    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
340        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
341        cater for a lack of strerror(). These oversights have been fixed.
343    9.  Added --match-limit and --recursion-limit to pcregrep.
345    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
347    11. When the -o option was used, pcregrep was setting a return code of 1, even
348        when matches were found, and --line-buffered was not being honoured.
350    12. Added an optional parentheses number to the -o and --only-matching options
351        of pcregrep.
353    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
354        can match an empty string. The code to do it in pcretest and pcredemo
355        needed fixing:
357        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
358            only one byte after an empty string match just before CRLF (this case
359            just got forgotten; "any" and "anycrlf" were OK).
361        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
362            mode when an empty string match preceded an ASCII character followed by
363            a non-ASCII character. (The code for advancing by one character rather
364            than one byte was nonsense.)
366        (c) The pcredemo.c sample program did not have any code at all to handle
367            the cases when CRLF is a valid newline sequence.
369    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
370        as a starting offset was within the subject string. There is now a new
371        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
372        negative or greater than the length of the string. In order to test this,
373        pcretest is extended to allow the setting of negative starting offsets.
375    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
376        starting offset points to the beginning of a UTF-8 character was
377        unnecessarily clumsy. I tidied it up.
379    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
380        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
382    17. Nobody had reported that the --include_dir option, which was added in
383        release 7.7 should have been called --include-dir (hyphen, not underscore)
384        for compatibility with GNU grep. I have changed it to --include-dir, but
385        left --include_dir as an undocumented synonym, and the same for
386        --exclude-dir, though that is not available in GNU grep, at least as of
387        release 2.5.4.
389    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
390        characters from a string of bytes) have been redefined so as not to use
391        loops, in order to improve performance in some environments. At the same
392        time, I abstracted some of the common code into auxiliary macros to save
393        repetition (this should not affect the compiled code).
395    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
396        compile-time error is now given if \c is not followed by an ASCII
397        character, that is, a byte less than 128. (In EBCDIC mode, the code is
398        different, and any byte value is allowed.)
400    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
401        START_OPTIMIZE option, which is now allowed at compile time - but just
402        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
403        to pcregrep and other applications that have no direct access to PCRE
404        options. The new /Y option in pcretest sets this option when calling
405        pcre_compile().
407    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
408        back references. Groups containing recursive back references were forced to
409        be atomic by that change, but in the case of named groups, the amount of
410        memory required was incorrectly computed, leading to "Failed: internal
411        error: code overflow". This has been fixed.
413    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
414        pcretest.c, to avoid build problems in some Borland environments.
417    Version 8.10 25-Jun-2010
418    ------------------------
420    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
421        THEN.
423    2.  (*ACCEPT) was not working when inside an atomic group.
425    3.  Inside a character class, \B is treated as a literal by default, but
426        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
427        causes the error). The code is unchanged, but I tidied the documentation.
429    4.  Inside a character class, PCRE always treated \R and \X as literals,
430        whereas Perl faults them if its -w option is set. I have changed PCRE so
431        that it faults them when PCRE_EXTRA is set.
433    5.  Added support for \N, which always matches any character other than
434        newline. (It is the same as "." when PCRE_DOTALL is not set.)
436    6.  When compiling pcregrep with newer versions of gcc which may have
437        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
438        declared with attribute warn_unused_result" were given. Just casting the
439        result to (void) does not stop the warnings; a more elaborate fudge is
440        needed. I've used a macro to implement this.
442    7.  Minor change to pcretest.c to avoid a compiler warning.
444    8.  Added four artifical Unicode properties to help with an option to make
445        \s etc use properties (see next item). The new properties are: Xan
446        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
448    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
449        use Unicode properties. (*UCP) at the start of a pattern can be used to set
450        this option. Modified pcretest to add /W to test this facility. Added
451        REG_UCP to make it available via the POSIX interface.
453    10. Added --line-buffered to pcregrep.
455    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
456        studied, and the match started with a letter with a code point greater than
457        127 whose first byte was different to the first byte of the other case of
458        the letter, the other case of this starting letter was not recognized
459        (#976).
461    12. If a pattern that was studied started with a repeated Unicode property
462        test, for example, \p{Nd}+, there was the theoretical possibility of
463        setting up an incorrect bitmap of starting bytes, but fortunately it could
464        not have actually happened in practice until change 8 above was made (it
465        added property types that matched character-matching opcodes).
467    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
468        possible starting bytes for non-anchored patterns.
470    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
471        \R, and also a number of cases that involve Unicode properties, both
472        explicit and implicit when PCRE_UCP is set.
474    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
475        input, it could crash or give wrong results if characters with values
476        greater than 0xc0 were present in the subject string. (Detail: it assumed
477        UTF-8 input when processing these items.)
479    16. Added a lot of (int) casts to avoid compiler warnings in systems where
480        size_t is 64-bit (#991).
482    17. Added a check for running out of memory when PCRE is compiled with
483        --disable-stack-for-recursion (#990).
485    18. If the last data line in a file for pcretest does not have a newline on
486        the end, a newline was missing in the output.
488    19. The default pcre_chartables.c file recognizes only ASCII characters (values
489        less than 128) in its various bitmaps. However, there is a facility for
490        generating tables according to the current locale when PCRE is compiled. It
491        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
492        characters, are recognized by isspace() and therefore were getting set in
493        these tables, and indeed these tables seem to approximate to ISO 8859. This
494        caused a problem in UTF-8 mode when pcre_study() was used to create a list
495        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
496        which of course cannot start UTF-8 characters. I have changed the code so
497        that only real ASCII characters (less than 128) and the correct starting
498        bytes for UTF-8 encodings are set for characters greater than 127 when in
499        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
500        altogether.)
502    20. Added the /T option to pcretest so as to be able to run tests with non-
503        standard character tables, thus making it possible to include the tests
504        used for 19 above in the standard set of tests.
506    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
507        reference to a subpattern the other side of a comment that contains an
508        opening parenthesis caused either an internal compiling error, or a
509        reference to the wrong subpattern.
512    Version 8.02 19-Mar-2010
513    ------------------------
515    1.  The Unicode data tables have been updated to Unicode 5.2.0.
517    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
518        configured.
520    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
521        original author of that file, following a query about its status.
523    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
524        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
526    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
527        quantifier applied to a forward-referencing subroutine call, could compile
528        incorrect code or give the error "internal error: previously-checked
529        referenced subpattern not found".
531    6.  Both MS Visual Studio and Symbian OS have problems with initializing
532        variables to point to external functions. For these systems, therefore,
533        pcre_malloc etc. are now initialized to local functions that call the
534        relevant global functions.
536    7.  There were two entries missing in the vectors called coptable and poptable
537        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
538        I've fixed the data, and added a kludgy way of testing at compile time that
539        the lengths are correct (equal to the number of opcodes).
541    8.  Following on from 7, I added a similar kludge to check the length of the
542        eint vector in pcreposix.c.
544    9.  Error texts for pcre_compile() are held as one long string to avoid too
545        much relocation at load time. To find a text, the string is searched,
546        counting zeros. There was no check for running off the end of the string,
547        which could happen if a new error number was added without updating the
548        string.
550    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
552    11. \K was not working if it appeared in an atomic group or in a group that
553        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
554        \K is "not well defined" if used in an assertion. PCRE now accepts it if
555        the assertion is positive, but not if it is negative.
557    12. Change 11 fortuitously reduced the size of the stack frame used in the
558        "match()" function of pcre_exec.c by one pointer. Forthcoming
559        implementation of support for (*MARK) will need an extra pointer on the
560        stack; I have reserved it now, so that the stack frame size does not
561        decrease.
563    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
564        item in branch that calls a recursion is a subroutine call - as in the
565        second branch in the above example - was incorrectly given the compile-
566        time error "recursive call could loop indefinitely" because pcre_compile()
567        was not correctly checking the subroutine for matching a non-empty string.
569    14. The checks for overrunning compiling workspace could trigger after an
570        overrun had occurred. This is a "should never occur" error, but it can be
571        triggered by pathological patterns such as hundreds of nested parentheses.
572        The checks now trigger 100 bytes before the end of the workspace.
574    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
577    Version 8.01 19-Jan-2010
578    ------------------------
580    1.  If a pattern contained a conditional subpattern with only one branch (in
581        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
582        computed the wrong minimum data length (which is of course zero for such
583        subpatterns). This could cause incorrect "no match" results.
585    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
586        the pattern is reset in the first branch, pcre_compile() failed with
587        "internal error: code overflow at offset...". This happened only when
588        the reset was to the original external option setting. (An optimization
589        abstracts leading options settings into an external setting, which was the
590        cause of this.)
592    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
593        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
594        assertion pattern did not match (meaning that the assertion was true), it
595        was incorrectly treated as false if the SKIP had been reached during the
596        matching. This also applied to assertions used as conditions.
598    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
599        assertion subpattern, including such a pattern used as a condition,
600        unpredictable results occurred, instead of the error return
603    5.  The C++ GlobalReplace function was not working like Perl for the special
604        situation when an empty string is matched. It now does the fancy magic
605        stuff that is necessary.
607    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
608        removed. (These were left over from very, very early versions of PCRE.)
610    7.  Some cosmetic changes to the code to make life easier when compiling it
611        as part of something else:
613        (a) Change DEBUG to PCRE_DEBUG.
615        (b) In pcre_compile(), rename the member of the "branch_chain" structure
616            called "current" as "current_branch", to prevent a collision with the
617            Linux macro when compiled as a kernel module.
619        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
620            prevent a collision with the Linux macro when compiled as a kernel
621            module.
623    8.  In pcre_compile() there are some checks for integer overflows that used to
624        cast potentially large values to (double). This has been changed to that
625        when building, a check for int64_t is made, and if it is found, it is used
626        instead, thus avoiding the use of floating point arithmetic. (There is no
627        other use of FP in PCRE.) If int64_t is not found, the fallback is to
628        double.
630    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
631        2005 (difference between two addresses compared to an unsigned value).
633    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
634        custom one, because of the following reported problem in Windows:
636          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
637              under Win32.
638          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
639              therefore missing the function definition.
640          - The compiler thus generates a "C" signature for the test function.
641          - The linker fails to find the "C" function.
642          - PCRE fails to configure if asked to do so against libbz2.
644    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
645        messages were output:
647          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
648          rerunning libtoolize, to keep the correct libtool macros in-tree.
649          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
651        I have done both of these things.
653    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
654        most of the time, it *can* run out if it is given a pattern that contains a
655        runaway infinite recursion. I updated the discussion in the pcrestack man
656        page.
658    13. Now that we have gone to the x.xx style of version numbers, the minor
659        version may start with zero. Using 08 or 09 is a bad idea because users
660        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
661        interpreted as invalid octal numbers. I've updated the previous comment in
662        configure.ac, and also added a check that gives an error if 08 or 09 are
663        used.
665    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
666        causing partial matching to fail when the end of the subject matched \W
667        in a UTF-8 pattern where \W was quantified with a minimum of 3.
669    15. There were some discrepancies between the declarations in pcre_internal.h
670        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
671        their definitions. The declarations used "const uschar *" and the
672        definitions used USPTR. Even though USPTR is normally defined as "const
673        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
674        reported that: "This difference in casting confuses some C++ compilers, for
675        example, SunCC recognizes above declarations as different functions and
676        generates broken code for hbpcre." I have changed the declarations to use
677        USPTR.
679    16. GNU libtool is named differently on some systems. The autogen.sh script now
680        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
681        (FreeBSD).
683    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
684        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
685        comment: "Figure out how to create a longlong from a string: strtoll and
686        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
687        instance, but it only takes 2 args instead of 3!"
689    18. A subtle bug concerned with back references has been fixed by a change of
690        specification, with a corresponding code fix. A pattern such as
691        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
692        refers, was giving matches when it shouldn't. For example, xa=xaaa would
693        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
694        same bug. Such groups have to be quantified to be useful, or contained
695        inside another quantified group. (If there's no repetition, the reference
696        can never match.) The problem arises because, having left the group and
697        moved on to the rest of the pattern, a later failure that backtracks into
698        the group uses the captured value from the final iteration of the group
699        rather than the correct earlier one. I have fixed this in PCRE by forcing
700        any group that contains a reference to itself to be an atomic group; that
701        is, there cannot be any backtracking into it once it has completed. This is
702        similar to recursive and subroutine calls.
705    Version 8.00 19-Oct-09
706    ----------------------
708    1.  The table for translating pcre_compile() error codes into POSIX error codes
709        was out-of-date, and there was no check on the pcre_compile() error code
710        being within the table. This could lead to an OK return being given in
711        error.
713    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
714        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
715        in a Windows environment.
717    3.  The pcregrep --count option prints the count for each file even when it is
718        zero, as does GNU grep. However, pcregrep was also printing all files when
719        --files-with-matches was added. Now, when both options are given, it prints
720        counts only for those files that have at least one match. (GNU grep just
721        prints the file name in this circumstance, but including the count seems
722        more useful - otherwise, why use --count?) Also ensured that the
723        combination -clh just lists non-zero counts, with no names.
725    4.  The long form of the pcregrep -F option was incorrectly implemented as
726        --fixed_strings instead of --fixed-strings. This is an incompatible change,
727        but it seems right to fix it, and I didn't think it was worth preserving
728        the old behaviour.
730    5.  The command line items --regex=pattern and --regexp=pattern were not
731        recognized by pcregrep, which required --regex pattern or --regexp pattern
732        (with a space rather than an '='). The man page documented the '=' forms,
733        which are compatible with GNU grep; these now work.
735    6.  No libpcreposix.pc file was created for pkg-config; there was just
736        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
738    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
739        when UCP support is not needed, by modifying the Python script that
740        generates it from Unicode data files. This should not matter if the module
741        is correctly used as a library, but I received one complaint about 50K of
742        unwanted data. My guess is that the person linked everything into his
743        program rather than using a library. Anyway, it does no harm.
745    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
746        was a minimum greater than 1 for a wide character in a possessive
747        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
748        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
749        character. Chaos in the form of incorrect output or a compiling loop could
750        result.
752    9.  The restrictions on what a pattern can contain when partial matching is
753        requested for pcre_exec() have been removed. All patterns can now be
754        partially matched by this function. In addition, if there are at least two
755        slots in the offset vector, the offset of the earliest inspected character
756        for the match and the offset of the end of the subject are set in them when
757        PCRE_ERROR_PARTIAL is returned.
759    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
760        synonymous with PCRE_PARTIAL, for backwards compatibility, and
761        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
762        and may be more useful for multi-segment matching.
764    11. Partial matching with pcre_exec() is now more intuitive. A partial match
765        used to be given if ever the end of the subject was reached; now it is
766        given only if matching could not proceed because another character was
767        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
768        string "Z", which now yields "no match" instead of "partial match". In the
769        case of pcre_dfa_exec(), "no match" is given if every matching path for the
770        final character ended with (*FAIL).
772    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
773        if the pattern had a "must contain" character that was already found in the
774        earlier partial match, unless partial matching was again requested. For
775        example, with the pattern /dog.(body)?/, the "must contain" character is
776        "g". If the first part-match was for the string "dog", restarting with
777        "sbody" failed. This bug has been fixed.
779    13. The string returned by pcre_dfa_exec() after a partial match has been
780        changed so that it starts at the first inspected character rather than the
781        first character of the match. This makes a difference only if the pattern
782        starts with a lookbehind assertion or \b or \B (\K is not supported by
783        pcre_dfa_exec()). It's an incompatible change, but it makes the two
784        matching functions compatible, and I think it's the right thing to do.
786    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
787        so that the demonstration program is easily available in environments where
788        PCRE has not been installed from source.
790    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
791        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
792        library.
794    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
795        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
796        is not the first non-POSIX option to be added. Clearly some people find
797        these options useful.
799    17. If a caller to the POSIX matching function regexec() passes a non-zero
800        value for nmatch with a NULL value for pmatch, the value of
801        nmatch is forced to zero.
803    18. RunGrepTest did not have a test for the availability of the -u option of
804        the diff command, as RunTest does. It now checks in the same way as
805        RunTest, and also checks for the -b option.
807    19. If an odd number of negated classes containing just a single character
808        interposed, within parentheses, between a forward reference to a named
809        subpattern and the definition of the subpattern, compilation crashed with
810        an internal error, complaining that it could not find the referenced
811        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
812        [The bug was that it was starting one character too far in when skipping
813        over the character class, thus treating the ] as data rather than
814        terminating the class. This meant it could skip too much.]
816    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
817        /g option in pcretest when the pattern contains \K, which makes it possible
818        to have an empty string match not at the start, even when the pattern is
819        anchored. Updated pcretest and pcredemo to use this option.
821    21. If the maximum number of capturing subpatterns in a recursion was greater
822        than the maximum at the outer level, the higher number was returned, but
823        with unset values at the outer level. The correct (outer level) value is
824        now given.
826    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
827        PCRE did not set those parentheses (unlike Perl). I have now found a way to
828        make it do so. The string so far is captured, making this feature
829        compatible with Perl.
831    23. The tests have been re-organized, adding tests 11 and 12, to make it
832        possible to check the Perl 5.10 features against Perl 5.10.
834    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
835        pattern matches a fixed length string. PCRE did not allow this; now it
836        does. Neither allows recursion.
838    25. I finally figured out how to implement a request to provide the minimum
839        length of subject string that was needed in order to match a given pattern.
840        (It was back references and recursion that I had previously got hung up
841        on.) This code has now been added to pcre_study(); it finds a lower bound
842        to the length of subject needed. It is not necessarily the greatest lower
843        bound, but using it to avoid searching strings that are too short does give
844        some useful speed-ups. The value is available to calling programs via
845        pcre_fullinfo().
847    26. While implementing 25, I discovered to my embarrassment that pcretest had
848        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
849        study optimizations had never been tested with that matching function.
850        Oops. What is worse, even when it was passed study data, there was a bug in
851        pcre_dfa_exec() that meant it never actually used it. Double oops. There
852        were also very few tests of studied patterns with pcre_dfa_exec().
854    27. If (?| is used to create subpatterns with duplicate numbers, they are now
855        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
856        on the other side of the coin, they are no longer allowed to have different
857        names, because these cannot be distinguished in PCRE, and this has caused
858        confusion. (This is a difference from Perl.)
860    28. When duplicate subpattern names are present (necessarily with different
861        numbers, as required by 27 above), and a test is made by name in a
862        conditional pattern, either for a subpattern having been matched, or for
863        recursion in such a pattern, all the associated numbered subpatterns are
864        tested, and the overall condition is true if the condition is true for any
865        one of them. This is the way Perl works, and is also more like the way
866        testing by number works.
869    Version 7.9 11-Apr-09
870    ---------------------
872    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
873        (pcretest), all targets were linked against these libraries. This included
874        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
875        libraries. This caused unwanted dependencies to be created. This problem
876        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
877        pcretest is linked with readline.
879    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
880        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
881        moved outside it again, because FALSE and TRUE are already defined in AIX,
882        but BOOL is not.
884    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
885        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
887    4.  The pcregrep documentation said spaces were inserted as well as colons (or
888        hyphens) following file names and line numbers when outputting matching
889        lines. This is not true; no spaces are inserted. I have also clarified the
890        wording for the --colour (or --color) option.
892    5.  In pcregrep, when --colour was used with -o, the list of matching strings
893        was not coloured; this is different to GNU grep, so I have changed it to be
894        the same.
896    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
897        each matching line was coloured. Now it goes on to look for further matches
898        of any of the test patterns, which is the same behaviour as GNU grep.
900    7.  A pattern that could match an empty string could cause pcregrep to loop; it
901        doesn't make sense to accept an empty string match in pcregrep, so I have
902        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
903        seems to be how GNU grep behaves.
905    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
906        start or after a newline", because the conditional assertion was not being
907        correctly handled. The rule now is that both the assertion and what follows
908        in the first alternative must satisfy the test.
910    9.  If auto-callout was enabled in a pattern with a conditional group whose
911        condition was an assertion, PCRE could crash during matching, both with
912        pcre_exec() and pcre_dfa_exec().
914    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
915        used for matching.
917    11. Unicode property support in character classes was not working for
918        characters (bytes) greater than 127 when not in UTF-8 mode.
920    12. Added the -M command line option to pcretest.
922    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
924    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
926    16. Added comments and documentation about mis-use of no_arg in the C++
927        wrapper.
929    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
930        from Martin Jerabek that uses macro names for all relevant character and
931        string constants.
933    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
934        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
935        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
936        these, but not everybody uses configure.
938    19. A conditional group that had only one branch was not being correctly
939        recognized as an item that could match an empty string. This meant that an
940        enclosing group might also not be so recognized, causing infinite looping
941        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
942        with the subject "ab", where knowledge that the repeated group can match
943        nothing is needed in order to break the loop.
945    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
946        exec(), but without supplying a callout function, matching went wrong.
948    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
949        leak if the size of the offset vector was greater than 30. When the vector
950        is smaller, the saved offsets during recursion go onto a local stack
951        vector, but for larger vectors malloc() is used. It was failing to free
952        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
953        error, in fact).
955    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
956        heapframe that is used only when UTF-8 support is enabled. This caused no
957        problem, but was untidy.
959    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
960        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
961        included within another project.
963    24. Steven Van Ingelgem's patches to add more options to the CMake support,
964        slightly modified by me:
966          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
967              not building pcregrep.
969          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
970              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
972    25. Forward references, both numeric and by name, in patterns that made use of
973        duplicate group numbers, could behave incorrectly or give incorrect errors,
974        because when scanning forward to find the reference group, PCRE was not
975        taking into account the duplicate group numbers. A pattern such as
976        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
978    26. Changed a few more instances of "const unsigned char *" to USPTR, making
979        the feature of a custom pointer more persuasive (as requested by a user).
981    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
982        pcretest.c, inside #ifndefs, because it seems they are sometimes already
983        pre-defined.
985    28. Added support for (*UTF8) at the start of a pattern.
987    29. Arrange for flags added by the "release type" setting in CMake to be shown
988        in the configuration summary.
991    Version 7.8 05-Sep-08
992    ---------------------
994    1.  Replaced UCP searching code with optimized version as implemented for Ad
995        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
996        stage table and inline lookup instead of a function, giving speed ups of 2
997        to 5 times on some simple patterns that I tested. Permission was given to
998        distribute the MultiStage2.py script that generates the tables (it's not in
999        the tarball, but is in the Subversion repository).
1001    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1002        scripts.
1004    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1005        a group with a zero qualifier. The result of the study could be incorrect,
1006        or the function might crash, depending on the pattern.
1008    4.  Caseless matching was not working for non-ASCII characters in back
1009        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1010        It now works when Unicode Property Support is available.
1012    5.  In pcretest, an escape such as \x{de} in the data was always generating
1013        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1014        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1015        truncation.
1017    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1019    7.  Added two (int) casts to pcregrep when printing the difference of two
1020        pointers, in case they are 64-bit values.
1022    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1023        test 2 if it fails.
1025    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1026        and a #define of that name to empty if it is not externally set. This is to
1027        allow users of MSVC to set it if necessary.
1029    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1030        the convenience functions in the pcre_get.c source file.
1032    11. An option change at the start of a pattern that had top-level alternatives
1033        could cause overwriting and/or a crash. This command provoked a crash in
1034        some environments:
1036          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1038        This potential security problem was recorded as CVE-2008-2371.
1040    12. For a pattern where the match had to start at the beginning or immediately
1041        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1042        pcre_dfa_exec() could read past the end of the passed subject if there was
1043        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1044        pcretest so that it places the subject at the end of its malloc-ed buffer.
1046    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1047        exec() might read past the end of the data buffer in UTF-8 mode.
1049    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1050        the data contained the byte 0x85 as part of a UTF-8 character within its
1051        first line. This applied both to normal and DFA matching.
1053    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1054        /^[^d]*?$/8 failed to match "abc".
1056    16. Added a missing copyright notice to pcrecpp_internal.h.
1058    17. Make it more clear in the documentation that values returned from
1059        pcre_exec() in ovector are byte offsets, not character counts.
1061    18. Tidied a few places to stop certain compilers from issuing warnings.
1063    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1064        supplied by Stefan Weber. I made a further small update for 7.8 because
1065        there is a change of source arrangements: the pcre_searchfuncs.c module is
1066        replaced by pcre_ucd.c.
1069    Version 7.7 07-May-08
1070    ---------------------
1072    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1073        a string to a long long, pretend we don't even have a long long." This is
1074        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1076    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1077        pre-7.6 versions, which defined a global no_arg variable instead of putting
1078        it in the RE class. (See also #8 below.)
1080    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1081        Lopes.
1083    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1085        (1) The include/exclude patterns were being applied to the whole pathnames
1086            of files, instead of just to the final components.
1088        (2) If there was more than one level of directory, the subdirectories were
1089            skipped unless they satisfied the include/exclude conditions. This is
1090            inconsistent with GNU grep (and could even be seen as contrary to the
1091            pcregrep specification - which I improved to make it absolutely clear).
1092            The action now is always to scan all levels of directory, and just
1093            apply the include/exclude patterns to regular files.
1095    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1096        --exclude_dir in the tests to avoid scanning .svn directories.
1098    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1099        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1100        doesn't support NULs in patterns.
1102    7.  Added some missing "const"s to declarations of static tables in
1103        pcre_compile.c and pcre_dfa_exec.c.
1105    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1106        caused by fix #2  above. (Subsequently also a second patch to fix the
1107        first patch. And a third patch - this was a messy problem.)
1109    9.  Applied Craig's patch to remove the use of push_back().
1111    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1112        matching function regexec().
1114    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1115        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1116        references. PCRE supports relative numbers with this syntax (I don't think
1117        Oniguruma does).
1119    12. Previously, a group with a zero repeat such as (...){0} was completely
1120        omitted from the compiled regex. However, this means that if the group
1121        was called as a subroutine from elsewhere in the pattern, things went wrong
1122        (an internal error was given). Such groups are now left in the compiled
1123        pattern, with a new opcode that causes them to be skipped at execution
1124        time.
1126    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1127        to the way PCRE behaves:
1129        (a) A lone ] character is dis-allowed (Perl treats it as data).
1131        (b) A back reference to an unmatched subpattern matches an empty string
1132            (Perl fails the current match path).
1134        (c) A data ] in a character class must be notated as \] because if the
1135            first data character in a class is ], it defines an empty class. (In
1136            Perl it is not possible to have an empty class.) The empty class []
1137            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1138            The negative empty class [^] matches any one character, independently
1139            of the DOTALL setting.
1141    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1142        non-existent subpattern following a character class starting with ']' and
1143        containing () gave an internal compiling error instead of "reference to
1144        non-existent subpattern". Fortunately, when the pattern did exist, the
1145        compiled code was correct. (When scanning forwards to check for the
1146        existencd of the subpattern, it was treating the data ']' as terminating
1147        the class, so got the count wrong. When actually compiling, the reference
1148        was subsequently set up correctly.)
1150    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1151        it was being rejected as not supported by pcre_dfa_exec(), even though
1152        other assertions are supported. I have made pcre_dfa_exec() support
1153        (*FAIL).
1155    16. The implementation of 13c above involved the invention of a new opcode,
1156        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1157        cannot be changed at match time, I realized I could make a small
1158        improvement to matching performance by compiling OP_ALLANY instead of
1159        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1160        on the OP_ANY path.
1162    17. Compiling pcretest on Windows with readline support failed without the
1163        following two fixes: (1) Make the unistd.h include conditional on
1164        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1166    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1167        ncurses library to be included for pcretest when ReadLine support is
1168        requested, but also to allow for it to be overridden. This patch came from
1169        Daniel Bergström.
1171    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1172        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1173        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1174        spotting this.
1177    Version 7.6 28-Jan-08
1178    ---------------------
1180    1.  A character class containing a very large number of characters with
1181        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1182        overflow.
1184    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1185        HAVE_LONG_LONG is not defined.
1187    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1188        bring them up to date and include new features. This patch includes:
1190        - Fixed PH's badly added libz and libbz2 support.
1191        - Fixed a problem with static linking.
1192        - Added pcredemo. [But later removed - see 7 below.]
1193        - Fixed dftables problem and added an option.
1194        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1195            HAVE_LONG_LONG.
1196        - Added readline support for pcretest.
1197        - Added an listing of the option settings after cmake has run.
1199    4.  A user submitted a patch to Makefile that makes it easy to create
1200        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1201        Makefile.am that cause it to include this special target, without
1202        affecting anything else. Note that the same mingw target plus all
1203        the other distribution libraries and programs are now supported
1204        when configuring with CMake (see 6 below) instead of with
1205        Configure/Make.
1207    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1208        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1209        exported in the Windows port". It has not yet been confirmed that the patch
1210        solves the problem, but it does no harm.
1212    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1213        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1214        with CMake, and also correct the comment about stack recursion.
1216    7.  Remove the automatic building of pcredemo from the ./configure system and
1217        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1218        of a program that users should build themselves after PCRE is installed, so
1219        building it automatically is not really right. What is more, it gave
1220        trouble in some build environments.
1222    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1225    Version 7.5 10-Jan-08
1226    ---------------------
1228    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1229        values in parens when parsing an RE using the C++ wrapper."
1231    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1232        Characters greater than 255 were excluded from the class instead of being
1233        included.
1235    3.  The same bug as (2) above applied to negated POSIX classes such as
1236        [:^space:].
1238    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1239        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1240        I have changed it.
1242    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1243        first named subpattern) and a construct such as (?&a) would reference the
1244        first named subpattern whose name started with "a" (in other words, the
1245        length check was missing). Both these problems are fixed. "Subpattern name
1246        expected" is now given for (?&) (a zero-length name), and this patch also
1247        makes it give the same error for \k'' (previously it complained that that
1248        was a reference to a non-existent subpattern).
1250    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1251        this is right because (?- can be followed by option settings as well as by
1252        digits. I have, however, made the messages clearer.
1254    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1255        than the number used in the conditional) now cause a compile-time error.
1256        This is actually not compatible with Perl, which accepts such patterns, but
1257        treats the conditional as always being FALSE (as PCRE used to), but it
1258        seems to me that giving a diagnostic is better.
1260    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1261        and messages.
1263    9.  Fix two occurrences of "backslash" in comments that should have been
1264        "backspace".
1266    10. Remove two redundant lines of code that can never be obeyed (their function
1267        was moved elsewhere).
1269    11. The program that makes PCRE's Unicode character property table had a bug
1270        which caused it to generate incorrect table entries for sequences of
1271        characters that have the same character type, but are in different scripts.
1272        It amalgamated them into a single range, with the script of the first of
1273        them. In other words, some characters were in the wrong script. There were
1274        thirteen such cases, affecting characters in the following ranges:
1276          U+002b0 - U+002c1
1277          U+0060c - U+0060d
1278          U+0061e - U+00612
1279          U+0064b - U+0065e
1280          U+0074d - U+0076d
1281          U+01800 - U+01805
1282          U+01d00 - U+01d77
1283          U+01d9b - U+01dbf
1284          U+0200b - U+0200f
1285          U+030fc - U+030fe
1286          U+03260 - U+0327f
1287          U+0fb46 - U+0fbb1
1288          U+10450 - U+1049d
1290    12. The -o option (show only the matching part of a line) for pcregrep was not
1291        compatible with GNU grep in that, if there was more than one match in a
1292        line, it showed only the first of them. It now behaves in the same way as
1293        GNU grep.
1295    13. If the -o and -v options were combined for pcregrep, it printed a blank
1296        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1297        does the same. The return code can be used to tell if there were any
1298        non-matching lines.
1300    14. Added --file-offsets and --line-offsets to pcregrep.
1302    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1303        infinitely looping recursion. The bug was that positive lookaheads were not
1304        being skipped when checking for a possible empty match (negative lookaheads
1305        and both kinds of lookbehind were skipped).
1307    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1308        inclusion of <windows.h> to before rather than after the definition of
1309        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1311    17. Specifying a possessive quantifier with a specific limit for a Unicode
1312        character property caused pcre_compile() to compile bad code, which led at
1313        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1314        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1315        caused the error; without that there was no problem.
1317    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1319    19. Added --enable-pcretest-libreadline.
1321    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1322        RE::GlobalReplace(). As a result, the number of replacements returned was
1323        double what it should be. I removed one of the increments, but Craig sent a
1324        later patch that removed the other one (the right fix) and added unit tests
1325        that check the return values (which was not done before).
1327    21. Several CMake things:
1329        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1330            the names libpcre and libpcreposix, not just pcre and pcreposix.
1332        (2) The above change means that pcretest and pcregrep are now correctly
1333            linked with the newly-built libraries, not previously installed ones.
1337    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1338        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1339        UTF-8 newline character). The key issue is that the pattern starts .*;
1340        this means that the match must be either at the beginning, or after a
1341        newline. The bug was in the code for advancing after a failed match and
1342        checking that the new position followed a newline. It was not taking
1343        account of UTF-8 characters correctly.
1345    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1346        character classes. PCRE was not treating the sequence [:...:] as a
1347        character class unless the ... were all letters. Perl, however, seems to
1348        allow any characters between [: and :], though of course it rejects as
1349        unknown any "names" that contain non-letters, because all the known class
1350        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1351        for example, whereas PCRE did not - it did not recognize a POSIX character
1352        class. This seemed a bit dangerous, so the code has been changed to be
1353        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1354        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1355        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1356        Perl does, and where it didn't before.
1358    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1359        Windows environments %n is disabled by default.
1362    Version 7.4 21-Sep-07
1363    ---------------------
1365    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1366        means that a class such as [\s] counted as "explicit reference to CR or
1367        LF". That isn't really right - the whole point of the change was to try to
1368        help when there was an actual mention of one of the two characters. So now
1369        the change happens only if \r or \n (or a literal CR or LF) character is
1370        encountered.
1372    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1373        of both had grown to the point where there were only 3 bits left.
1374        Fortunately, there was spare space in the data structure, and so I have
1375        moved the internal flags into a new 16-bit field to free up more option
1376        bits.
1378    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1379        but did not set the internal JCHANGED flag - either of these is enough to
1380        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1381        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1382        start sets both bits.
1384    4.  Added options (at build time, compile time, exec time) to change \R from
1385        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1387    5.  doc/pcresyntax.html was missing from the distribution.
1389    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1390        compatibility, even though it is no longer used.
1392    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1393        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1394        windows.h file is present (where different names are used). [This was
1395        reversed later after testing - see 16 below.]
1397    8.  Changed all #include <config.h> to #include "config.h". There were also
1398        some further <pcre.h> cases that I changed to "pcre.h".
1400    9.  When pcregrep was used with the --colour option, it missed the line ending
1401        sequence off the lines that it output.
1403    10. It was pointed out to me that arrays of string pointers cause lots of
1404        relocations when a shared library is dynamically loaded. A technique of
1405        using a single long string with a table of offsets can drastically reduce
1406        these. I have refactored PCRE in four places to do this. The result is
1407        dramatic:
1409          Originally:                          290
1410          After changing UCP table:            187
1411          After changing error message table:   43
1412          After changing table of "verbs"       36
1413          After changing table of Posix names   22
1415        Thanks to the folks working on Gregex for glib for this insight.
1417    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1418        unicode-properties was also set.
1420    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1422    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1423        checked only for CRLF.
1425    14. Added casts to pcretest.c to avoid compiler warnings.
1427    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1429    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1430        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1431        entirely. This removes changes made in 7 above.
1433    17. The CMake files have been updated, and there is now more information about
1434        building with CMake in the NON-UNIX-USE document.
1437    Version 7.3 28-Aug-07
1438    ---------------------
1440     1. In the rejigging of the build system that eventually resulted in 7.1, the
1441        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1442        brackets there is not right, since it causes compilers to look for an
1443        installed pcre.h, not the version that is in the source that is being
1444        compiled (which of course may be different). I have changed it back to:
1446          #include "pcre.h"
1448        I have a vague recollection that the change was concerned with compiling in
1449        different directories, but in the new build system, that is taken care of
1450        by the VPATH setting the Makefile.
1452     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1453        when the subject happened to end in the byte 0x85 (e.g. if the last
1454        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1455        characters but of course it shouldn't be taken as a newline when it is part
1456        of another character. The bug was that, for an unlimited repeat of . in
1457        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1458        characters when looking for a newline.
1460     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1462     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1463        in debug output.
1465     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1466        long printing in the pcrecpp unittest when running under MinGW.
1468     6. ESC_K was left out of the EBCDIC table.
1470     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1471        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1472        limit also applies to "virtual nesting" when a pattern is recursive, and in
1473        this case 1000 isn't so big. I have been able to remove this limit at the
1474        expense of backing off one optimization in certain circumstances. Normally,
1475        when pcre_exec() would call its internal match() function recursively and
1476        immediately return the result unconditionally, it uses a "tail recursion"
1477        feature to save stack. However, when a subpattern that can match an empty
1478        string has an unlimited repetition quantifier, it no longer makes this
1479        optimization. That gives it a stack frame in which to save the data for
1480        checking that an empty string has been matched. Previously this was taken
1481        from the 1000-entry workspace that had been reserved. So now there is no
1482        explicit limit, but more stack is used.
1484     8. Applied Daniel's patches to solve problems with the import/export magic
1485        syntax that is required for Windows, and which was going wrong for the
1486        pcreposix and pcrecpp parts of the library. These were overlooked when this
1487        problem was solved for the main library.
1489     9. There were some crude static tests to avoid integer overflow when computing
1490        the size of patterns that contain repeated groups with explicit upper
1491        limits. As the maximum quantifier is 65535, the maximum group length was
1492        set at 30,000 so that the product of these two numbers did not overflow a
1493        32-bit integer. However, it turns out that people want to use groups that
1494        are longer than 30,000 bytes (though not repeat them that many times).
1495        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1496        made it possible to implement the integer overflow checks in a much more
1497        dynamic way, which I have now done. The artificial limitation on group
1498        length has been removed - we now have only the limit on the total length of
1499        the compiled pattern, which depends on the LINK_SIZE setting.
1501    10. Fixed a bug in the documentation for get/copy named substring when
1502        duplicate names are permitted. If none of the named substrings are set, the
1503        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1504        empty string.
1506    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1507        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1508        because the ] is interpreted as the first data character and the
1509        terminating ] is not found. PCRE has been made compatible with Perl in this
1510        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1511        cause memory overwriting.
1513    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1514        string has been matched (to stop an infinite loop). It was not recognizing
1515        a conditional subpattern that could match an empty string if that
1516        subpattern was within another subpattern. For example, it looped when
1517        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1518        condition was not nested. This bug has been fixed.
1520    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1521        past the start of the subject in the presence of bytes with the top bit
1522        set, for example "\x8aBCD".
1524    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1525        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1527    14. Optimized (?!) to (*FAIL).
1529    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1530        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1531        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1532        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1533        does: it's just the validity check that is more restrictive.
1535    16. Inserted checks for integer overflows during escape sequence (backslash)
1536        processing, and also fixed erroneous offset values for syntax errors during
1537        backslash processing.
1539    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1540        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1542    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1543        caused an overrun.
1545    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1546        something other than just ASCII characters) inside a group that had an
1547        unlimited repeat caused a loop at compile time (while checking to see
1548        whether the group could match an empty string).
1550    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1551        [\P{Any}] did so. (Error in the code for printing property names.)
1553    21. An orphan \E inside a character class could cause a crash.
1555    22. A repeated capturing bracket such as (A)? could cause a wild memory
1556        reference during compilation.
1558    23. There are several functions in pcre_compile() that scan along a compiled
1559        expression for various reasons (e.g. to see if it's fixed length for look
1560        behind). There were bugs in these functions when a repeated \p or \P was
1561        present in the pattern. These operators have additional parameters compared
1562        with \d, etc, and these were not being taken into account when moving along
1563        the compiled data. Specifically:
1565        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1566            length.
1568        (b) An item such as \pL+ within a repeated group could cause crashes or
1569            loops.
1571        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1572            "reference to non-existent subpattern" error.
1574        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1576    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1577        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1579    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1581    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1582        character were causing crashes (broken optimization).
1584    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1585        \p or \P) caused a compile-time loop.
1587    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1588        break. For example, the unstudied pattern [\r\n]A does not match the string
1589        "\r\nA" because change 7.0/46 below moves the current point on by two
1590        characters after failing to match at the start. However, the pattern \nA
1591        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1592        the same is true. There doesn't seem any very clean way out of this, but
1593        what I have chosen to do makes the common cases work: PCRE now takes note
1594        of whether there can be an explicit match for \r or \n anywhere in the
1595        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1596        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1597        pattern has explicit CR or LF references.
1599    29. Added (*CR) etc for changing newline setting at start of pattern.
1602    Version 7.2 19-Jun-07
1603    ---------------------
1605     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1606        which is apparently normally available under Windows.
1608     2. Re-jig the pcregrep tests with different newline settings in an attempt
1609        to make them independent of the local environment's newline setting.
1611     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1613     4. Some of the "internals" tests were previously cut out when the link size
1614        was not 2, because the output contained actual offsets. The recent new
1615        "Z" feature of pcretest means that these can be cut out, making the tests
1616        usable with all link sizes.
1618     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1619        stack recursion. This gives a massive performance boost under BSD, but just
1620        a small improvement under Linux. However, it saves one field in the frame
1621        in all cases.
1623     6. Added more features from the forthcoming Perl 5.10:
1625        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1626            recursion call. It refers to the nth most recently opened parentheses.
1628        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1629            to be opened parentheses.
1631        (c) Conditions that refer to capturing parentheses can be specified
1632            relatively, for example, (?(-2)... or (?(+3)...
1634        (d) \K resets the start of the current match so that everything before
1635            is not part of it.
1637        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1639        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1640            reference syntax.
1642        (g) (?| introduces a group in which the numbering of parentheses in each
1643            alternative starts with the same number.
1645        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1647     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1650     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1651        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1652        for detecting groups that can match an empty string.
1654     9. A pattern with a very large number of alternatives (more than several
1655        hundred) was running out of internal workspace during the pre-compile
1656        phase, where pcre_compile() figures out how much memory will be needed. A
1657        bit of new cunning has reduced the workspace needed for groups with
1658        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1659        workspace instead of running out of the 4096 that are available.
1661    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1663    11. Applied patch from Google to remove an optimization that didn't quite work.
1664        The report of the bug said:
1666          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1667          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1668          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1670    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1671        it matched the wrong number of bytes.
1674    Version 7.1 24-Apr-07
1675    ---------------------
1677     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1678        that is more "standard", making use of automake and other Autotools. There
1679        is some re-arrangement of the files and adjustment of comments consequent
1680        on this.
1682     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1683        for recursive directory scanning broke on some systems because the files
1684        are not scanned in any specific order and on different systems the order
1685        was different. A call to "sort" has been inserted into RunGrepTest for the
1686        approprate test as a short-term fix. In the longer term there may be an
1687        alternative.
1689     3. I had an email from Eric Raymond about problems translating some of PCRE's
1690        man pages to HTML (despite the fact that I distribute HTML pages, some
1691        people do their own conversions for various reasons). The problems
1692        concerned the use of low-level troff macros .br and .in. I have therefore
1693        removed all such uses from the man pages (some were redundant, some could
1694        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1695        HTML has been updated to handle .nf/.fi and to complain if it encounters
1696        .br or .in.
1698     4. Updated comments in configure.ac that get placed in config.h.in and also
1699        arranged for config.h to be included in the distribution, with the name
1700        config.h.generic, for the benefit of those who have to compile without
1701        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1703     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1704        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1705        makevp.bat for the current PCRE, using the additional files
1706        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1708     6. A Windows user reported a minor discrepancy with test 2, which turned out
1709        to be caused by a trailing space on an input line that had got lost in his
1710        copy. The trailing space was an accident, so I've just removed it.
1712     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1713        that is needed.
1715     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1716        as "const" (a) because they are and (b) because it helps the PHP
1717        maintainers who have recently made a script to detect big data structures
1718        in the php code that should be moved to the .rodata section. I remembered
1719        to update Builducptable as well, so it won't revert if ucptable.h is ever
1720        re-created.
1722     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1723        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1724        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1725        support is not required. This saves 1.5-2K of code, which is important in
1726        some applications.
1728        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1729        so as not to refer to the tables, even though these functions will never be
1730        called when UTF-8 support is disabled. Otherwise there are problems with a
1731        shared library.
1733    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1735        (a) It was defining its arguments as char * instead of void *.
1737        (b) It was assuming that all moves were upwards in memory; this was true
1738            a long time ago when I wrote it, but is no longer the case.
1740        The emulated memove() is provided for those environments that have neither
1741        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1742        is clearly not the case, as these two bugs were recently reported.
1744    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1745        and Detrail to create the HTML documentation, the .txt form of the man
1746        pages, and it removes trailing spaces from listed files. It also creates
1747        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1748        case, it wraps all the #defines with #ifndefs. This script should be run
1749        before "make dist".
1751    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1752        with Unicode property support.
1754        (a) For a maximizing quantifier, if the two different cases of the
1755            character were of different lengths in their UTF-8 codings (there are
1756            some cases like this - I found 11), and the matching function had to
1757            back up over a mixture of the two cases, it incorrectly assumed they
1758            were both the same length.
1760        (b) When PCRE was configured to use the heap rather than the stack for
1761            recursion during matching, it was not correctly preserving the data for
1762            the other case of a UTF-8 character when checking ahead for a match
1763            while processing a minimizing repeat. If the check also involved
1764            matching a wide character, but failed, corruption could cause an
1765            erroneous result when trying to check for a repeat of the original
1766            character.
1768    13. Some tidying changes to the testing mechanism:
1770        (a) The RunTest script now detects the internal link size and whether there
1771            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1772            values substituted by "configure". (The RunGrepTest script already did
1773            this for UTF-8.) The configure.ac script no longer substitutes the
1774            relevant variables.
1776        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1777            with length and offset values. This means that the output is different
1778            for different internal link sizes. Test 2 is skipped for link sizes
1779            other than 2 because of this, bypassing the problem. Unfortunately,
1780            there was also a test in test 3 (the locale tests) that used /B and
1781            failed for link sizes other than 2. Rather than cut the whole test out,
1782            I have added a new /Z option to pcretest that replaces the length and
1783            offset values with spaces. This is now used to make test 3 independent
1784            of link size. (Test 2 will be tidied up later.)
1786    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1787        segmentation fault instead of returning the appropriate error message.
1789    15. In multiline mode when the newline sequence was set to "any", the pattern
1790        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1791        This doesn't seem right; it now treats the CRLF combination as the line
1792        ending, and so does not match in that case. It's only a pattern such as ^$
1793        that would hit this one: something like ^ABC$ would have failed after \r
1794        and then tried again after \r\n.
1796    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1797        in an attempt to make files that differ only in their line terminators
1798        compare equal. This works on Linux.
1800    17. Under certain error circumstances pcregrep might try to free random memory
1801        as it exited. This is now fixed, thanks to valgrind.
1803    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1804        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1805        was because its rules for how to advance for /g after matching an empty
1806        string at the end of a line did not allow for this case. They now check for
1807        it specially.
1809    20. pcretest is supposed to handle patterns and data of any length, by
1810        extending its buffers when necessary. It was getting this wrong when the
1811        buffer for a data line had to be extended.
1813    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1814        CRLF as a newline sequence.
1816    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1817        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1818        I have nevertheless tidied it up.
1820    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1822    24. Added a man page for pcre-config.
1825    Version 7.0 19-Dec-06
1826    ---------------------
1828     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1829        moving to gcc 4.1.1.
1831     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1832        sys/time.h, which is documented as needed for this function. It doesn't
1833        seem to matter on Linux, but it showed up on some releases of OS X.
1835     3. It seems that there are systems where bytes whose values are greater than
1836        127 match isprint() in the "C" locale. The "C" locale should be the
1837        default when a C program starts up. In most systems, only ASCII printing
1838        characters match isprint(). This difference caused the output from pcretest
1839        to vary, making some of the tests fail. I have changed pcretest so that:
1841        (a) When it is outputting text in the compiled version of a pattern, bytes
1842            other than 32-126 are always shown as hex escapes.
1844        (b) When it is outputting text that is a matched part of a subject string,
1845            it does the same, unless a different locale has been set for the match
1846            (using the /L modifier). In this case, it uses isprint() to decide.
1848     4. Fixed a major bug that caused incorrect computation of the amount of memory
1849        required for a compiled pattern when options that changed within the
1850        pattern affected the logic of the preliminary scan that determines the
1851        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1852        that the computed length was too small. The symptoms of this bug were
1853        either the PCRE error "internal error: code overflow" from pcre_compile(),
1854        or a glibc crash with a message such as "pcretest: free(): invalid next
1855        size (fast)". Examples of patterns that provoked this bug (shown in
1856        pcretest format) are:
1858          /(?-x: )/x
1859          /(?x)(?-x: \s*#\s*)/
1860          /((?i)[\x{c0}])/8
1861          /(?i:[\x{c0}])/8
1863        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1864        is now done differently.
1866     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1867        wrapper classes; (b) implement a new function in the C++ scanner that is
1868        more efficient than the old way of doing things because it avoids levels of
1869        recursion in the regex matching; (c) add a paragraph to the documentation
1870        for the FullMatch() function.
1872     6. The escape sequence \n was being treated as whatever was defined as
1873        "newline". Not only was this contrary to the documentation, which states
1874        that \n is character 10 (hex 0A), but it also went horribly wrong when
1875        "newline" was defined as CRLF. This has been fixed.
1877     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1878        was being set to -1 for the "end of line" case (supposedly a value that no
1879        character can have). Though this value is never used (the check for end of
1880        line is "zero bytes in current character"), it caused compiler complaints.
1881        I've changed it to 0xffffffff.
1883     8. In pcre_version.c, the version string was being built by a sequence of
1884        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1885        string (as it is for production releases) called a macro with an empty
1886        argument. The C standard says the result of this is undefined. The gcc
1887        compiler treats it as an empty string (which was what was wanted) but it is
1888        reported that Visual C gives an error. The source has been hacked around to
1889        avoid this problem.
1891     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1892        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1893        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1894        of them did).
1896    10. Originally, pcretest opened its input and output without "b"; then I was
1897        told that "b" was needed in some environments, so it was added for release
1898        5.0 to both the input and output. (It makes no difference on Unix-like
1899        systems.) Later I was told that it is wrong for the input on Windows. I've
1900        now abstracted the modes into two macros, to make it easier to fiddle with
1901        them, and removed "b" from the input mode under Windows.
1903    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1905    12. Added -help and --help to pcretest as an official way of being reminded
1906        of the options.
1908    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1909        and pcrecpp.cc because they annoy compilers at high warning levels.
1911    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1913    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1914        scripts are not C programs :-) and which was not noticed because it works
1915        on Linux.
1917    16. pcretest is supposed to handle any length of pattern and data line (as one
1918        line or as a continued sequence of lines) by extending its input buffer if
1919        necessary. This feature was broken for very long pattern lines, leading to
1920        a string of junk being passed to pcre_compile() if the pattern was longer
1921        than about 50K.
1923    17. I have done a major re-factoring of the way pcre_compile() computes the
1924        amount of memory needed for a compiled pattern. Previously, there was code
1925        that made a preliminary scan of the pattern in order to do this. That was
1926        OK when PCRE was new, but as the facilities have expanded, it has become
1927        harder and harder to keep it in step with the real compile phase, and there
1928        have been a number of bugs (see for example, 4 above). I have now found a
1929        cunning way of running the real compile function in a "fake" mode that
1930        enables it to compute how much memory it would need, while actually only
1931        ever using a few hundred bytes of working memory and without too many
1932        tests of the mode. This should make future maintenance and development
1933        easier. A side effect of this work is that the limit of 200 on the nesting
1934        depth of parentheses has been removed (though this was never a serious
1935        limitation, I suspect). However, there is a downside: pcre_compile() now
1936        runs more slowly than before (30% or more, depending on the pattern). I
1937        hope this isn't a big issue. There is no effect on runtime performance.
1939    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1940        newline (only possible for the last line of a file) and it was a
1941        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1943    19. Added additional timing features to pcretest. (1) The -tm option now times
1944        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1945        separate command line item, by a number that specifies the number of
1946        repeats to use when timing. The default is 50000; this gives better
1947        precision, but takes uncomfortably long for very large patterns.
1949    20. Extended pcre_study() to be more clever in cases where a branch of a
1950        subpattern has no definite first character. For example, (a*|b*)[cd] would
1951        previously give no result from pcre_study(). Now it recognizes that the
1952        first character must be a, b, c, or d.
1954    21. There was an incorrect error "recursive call could loop indefinitely" if
1955        a subpattern (or the entire pattern) that was being tested for matching an
1956        empty string contained only one non-empty item after a nested subpattern.
1957        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1958        incorrectly, because the \d was being skipped in the check.
1960    22. The pcretest program now has a new pattern option /B and a command line
1961        option -b, which is equivalent to adding /B to every pattern. This causes
1962        it to show the compiled bytecode, without the additional information that
1963        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1964        is the same as /B/I).
1966    23. A new optimization is now able automatically to treat some sequences such
1967        as a*b as a*+b. More specifically, if something simple (such as a character
1968        or a simple class like \d) has an unlimited quantifier, and is followed by
1969        something that cannot possibly match the quantified thing, the quantifier
1970        is automatically "possessified".
1972    24. A recursive reference to a subpattern whose number was greater than 39
1973        went wrong under certain circumstances in UTF-8 mode. This bug could also
1974        have affected the operation of pcre_study().
1976    25. Realized that a little bit of performance could be had by replacing
1977        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1979    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1981    27. Possessive quantifiers such as a++ were previously implemented by turning
1982        them into atomic groups such as ($>a+). Now they have their own opcodes,
1983        which improves performance. This includes the automatically created ones
1984        from 23 above.
1986    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1987        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1988        the first matched character to be a colon. This applied both to named and
1989        numbered groups.
1991    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1993    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1994        building PCRE on Windows easier, so I have included it in the distribution.
1996    31. There is now a check in pcretest against a ridiculously large number being
1997        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1998        loop, the loop is abandoned.
2000    32. Forward references to subpatterns in conditions such as (?(2)...) where
2001        subpattern 2 is defined later cause pcre_compile() to search forwards in
2002        the pattern for the relevant set of parentheses. This search went wrong
2003        when there were unescaped parentheses in a character class, parentheses
2004        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2006    33. "Subroutine" calls and backreferences were previously restricted to
2007        referencing subpatterns earlier in the regex. This restriction has now
2008        been removed.
2010    34. Added a number of extra features that are going to be in Perl 5.10. On the
2011        whole, these are just syntactic alternatives for features that PCRE had
2012        previously implemented using the Python syntax or my own invention. The
2013        other formats are all retained for compatibility.
2015        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2016            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2017            also .NET compatible.
2019        (b) A recursion or subroutine call to a named group can now be defined as
2020            (?&name) as well as (?P>name).
2022        (c) A backreference to a named group can now be defined as \k<name> or
2023            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2024            5.10, are also .NET compatible.
2026        (d) A conditional reference to a named group can now use the syntax
2027            (?(<name>) or (?('name') as well as (?(name).
2029        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2030            groups (named and numbered) that are never evaluated inline, but can be
2031            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2032            is always false. There may be only one alternative in such a group.
2034        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2035            as the simple (?(R). The condition is true only if the most recent
2036            recursion is that of the given number or name. It does not search out
2037            through the entire recursion stack.
2039        (g) The escape \gN or \g{N} has been added, where N is a positive or
2040            negative number, specifying an absolute or relative reference.
2042    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2043        some "unreachable code" warnings.
2045    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2046        things, this adds five new scripts.
2048    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2049        There were also incompatibilities regarding the handling of \Q..\E inside
2050        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2051        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2053    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2054        matches an empty string, and forcibly breaks the loop. There were bugs in
2055        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2056        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2057        separate and independent bugs (that affected different cases) have been
2058        fixed.
2060    39. Refactored the code to abolish the use of different opcodes for small
2061        capturing bracket numbers. This is a tidy that I avoided doing when I
2062        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2063        The new approach is not only tidier, it makes it possible to reduce the
2064        memory needed to fix the previous bug (38).
2066    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2067        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2068        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2069        mode.
2071    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2072        report.
2074    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2075        copy construction and assignment in the C++ wrapper.
2077    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2078        couple of bugs that could have given wrong results in the "--newline=crlf"
2079        case.
2081    44. Added a number of casts and did some reorganization of signed/unsigned int
2082        variables following suggestions from Dair Grant. Also renamed the variable
2083        "this" as "item" because it is a C++ keyword.
2085    45. Arranged for dftables to add
2087          #include "pcre_internal.h"
2089        to pcre_chartables.c because without it, gcc 4.x may remove the array
2090        definition from the final binary if PCRE is built into a static library and
2091        dead code stripping is activated.
2093    46. For an unanchored pattern, if a match attempt fails at the start of a
2094        newline sequence, and the newline setting is CRLF or ANY, and the next two
2095        characters are CRLF, advance by two characters instead of one.
2098    Version 6.7 04-Jul-06
2099    ---------------------
2101     1. In order to handle tests when input lines are enormously long, pcretest has
2102        been re-factored so that it automatically extends its buffers when
2103        necessary. The code is crude, but this _is_ just a test program. The
2104        default size has been increased from 32K to 50K.
2106     2. The code in pcre_study() was using the value of the re argument before
2107        testing it for NULL. (Of course, in any sensible call of the function, it
2108        won't be NULL.)
2110     3. The memmove() emulation function in pcre_internal.h, which is used on
2111        systems that lack both memmove() and bcopy() - that is, hardly ever -
2112        was missing a "static" storage class specifier.
2114     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2115        containing an extended class (one that cannot be represented by a bitmap
2116        because it contains high-valued characters or Unicode property items, e.g.
2117        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2118        pattern, but PCRE should not loop if you do not (it no longer does).
2119        [Detail: two cases were found: (a) a repeated subpattern containing an
2120        extended class; (b) a recursive reference to a subpattern that followed a
2121        previous extended class. It wasn't skipping over the extended class
2122        correctly when UTF-8 mode was not set.]
2124     5. A negated single-character class was not being recognized as fixed-length
2125        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2126        compile error "lookbehind assertion is not fixed length".
2128     6. The RunPerlTest auxiliary script was showing an unexpected difference
2129        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2130        write a Perl script that can interpret lines of an input file either as
2131        byte characters or as UTF-8, which is what "perltest" was being required to
2132        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2133        can't do is switch easily at run time between having the "use utf8;" pragma
2134        or not. In the end, I fudged it by using the RunPerlTest script to insert
2135        "use utf8;" explicitly for the UTF-8 tests.
2137     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2138        the end of the subject string, contrary to the documentation and to what
2139        Perl does. This was true of both matching functions. Now it matches only at
2140        the start of the subject and immediately after *internal* newlines.
2142     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2143        a pointer to an int instead of a pointer to an unsigned long int. This
2144        caused problems on 64-bit systems.
2146     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2147        instance of the 'standard' template library not being so standard".
2149    10. There was no check on the number of named subpatterns nor the maximum
2150        length of a subpattern name. The product of these values is used to compute
2151        the size of the memory block for a compiled pattern. By supplying a very
2152        long subpattern name and a large number of named subpatterns, the size
2153        computation could be caused to overflow. This is now prevented by limiting
2154        the length of names to 32 characters, and the number of named subpatterns
2155        to 10,000.
2157    11. Subpatterns that are repeated with specific counts have to be replicated in
2158        the compiled pattern. The size of memory for this was computed from the
2159        length of the subpattern and the repeat count. The latter is limited to
2160        65535, but there was no limit on the former, meaning that integer overflow
2161        could in principle occur. The compiled length of a repeated subpattern is
2162        now limited to 30,000 bytes in order to prevent this.
2164    12. Added the optional facility to have named substrings with the same name.
2166    13. Added the ability to use a named substring as a condition, using the
2167        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2168        are numbers (not recommended). Forward references are permitted.
2170    14. Added forward references in named backreferences (if you see what I mean).
2172    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2173        pattern could run off the end of the subject. For example, the pattern
2174        "(?s)(.{1,5})"8 did this with the subject "ab".
2176    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2177        PCRE_CASELESS was set when matching characters that were quantified with ?
2178        or *.
2180    17. A character class other than a single negated character that had a minimum
2181        but no maximum quantifier - for example [ab]{6,} - was not handled
2182        correctly by pce_dfa_exec(). It would match only one character.
2184    18. A valid (though odd) pattern that looked like a POSIX character
2185        class but used an invalid character after [ (for example [[,abc,]]) caused
2186        pcre_compile() to give the error "Failed: internal error: code overflow" or
2187        in some cases to crash with a glibc free() error. This could even happen if
2188        the pattern terminated after [[ but there just happened to be a sequence of
2189        letters, a binary zero, and a closing ] in the memory that followed.
2191    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2192        over the years. Originally (before any Unicode support), just the bottom 8
2193        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2194        output from "man perlunicode" includes this:
2196          The regular expression compiler produces polymorphic opcodes.  That
2197          is, the pattern adapts to the data and automatically switches to
2198          the Unicode character scheme when presented with Unicode data--or
2199          instead uses a traditional byte scheme when presented with byte
2200          data.
2202        Sadly, a wide octal escape does not cause a switch, and in a string with
2203        no other multibyte characters, these octal escapes are treated as before.
2204        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2205        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2206        Unicode string.
2208        I have not perpetrated such confusion in PCRE. Up till now, it took just
2209        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2210        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2211        translate to the appropriate multibyte character.
2213    29. Applied some refactoring to reduce the number of warnings from Microsoft
2214        and Borland compilers. This has included removing the fudge introduced
2215        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2216        a warning about an unused variable.
2218    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2219        characters since release 4.0, because Perl (from release 5.004) does not.
2220        [Or at least, is documented not to: some releases seem to be in conflict
2221        with the documentation.] However, when a pattern was studied with
2222        pcre_study() and all its branches started with \s, PCRE still included VT
2223        as a possible starting character. Of course, this did no harm; it just
2224        caused an unnecessary match attempt.
2226    22. Removed a now-redundant internal flag bit that recorded the fact that case
2227        dependency changed within the pattern. This was once needed for "required
2228        byte" processing, but is no longer used. This recovers a now-scarce options
2229        bit. Also moved the least significant internal flag bit to the most-
2230        significant bit of the word, which was not previously used (hangover from
2231        the days when it was an int rather than a uint) to free up another bit for
2232        the future.
2234    23. Added support for CRLF line endings as well as CR and LF. As well as the
2235        default being selectable at build time, it can now be changed at runtime
2236        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2237        specify that it is scanning data with non-default line endings.
2239    24. Changed the definition of CXXLINK to make it agree with the definition of
2240        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2242    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2243        recursions. This makes a big different to stack usage for some patterns.
2245    26. If a subpattern containing a named recursion or subroutine reference such
2246        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2247        the space required for the compiled pattern went wrong and gave too small a
2248        value. Depending on the environment, this could lead to "Failed: internal
2249        error: code overflow at offset 49" or "glibc detected double free or
2250        corruption" errors.
2252    27. Applied patches from Google (a) to support the new newline modes and (b) to
2253        advance over multibyte UTF-8 characters in GlobalReplace.
2255    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2256        difference for some implementation of PCRE in some Windows version.
2258    29. Added some extra testing facilities to pcretest:
2260        \q<number>   in a data line sets the "match limit" value
2261        \Q<number>   in a data line sets the "match recursion limt" value
2262        -S <number>  sets the stack size, where <number> is in megabytes
2264        The -S option isn't available for Windows.
2267    Version 6.6 06-Feb-06
2268    ---------------------
2270     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2271        in pcreposix.h. I have copied the definition from pcre.h.
2273     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2274        because pcre.h is no longer a built file.
2276     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2277        not normally included in the compiled code.
2280    Version 6.5 01-Feb-06
2281    ---------------------
2283     1. When using the partial match feature with pcre_dfa_exec(), it was not
2284        anchoring the second and subsequent partial matches at the new starting
2285        point. This could lead to incorrect results. For example, with the pattern
2286        /1234/, partially matching against "123" and then "a4" gave a match.
2288     2. Changes to pcregrep:
2290        (a) All non-match returns from pcre_exec() were being treated as failures
2291            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2292            error message is output. Some extra information is given for the
2293            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2294            probably the only errors that are likely to be caused by users (by
2295            specifying a regex that has nested indefinite repeats, for instance).
2296            If there are more than 20 of these errors, pcregrep is abandoned.
2298        (b) A binary zero was treated as data while matching, but terminated the
2299            output line if it was written out. This has been fixed: binary zeroes
2300            are now no different to any other data bytes.
2302        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2303            used to set a locale for matching. The --locale=xxxx long option has
2304            been added (no short equivalent) to specify a locale explicitly on the
2305            pcregrep command, overriding the environment variables.
2307        (d) When -B was used with -n, some line numbers in the output were one less
2308            than they should have been.
2310        (e) Added the -o (--only-matching) option.
2312        (f) If -A or -C was used with -c (count only), some lines of context were
2313            accidentally printed for the final match.
2315        (g) Added the -H (--with-filename) option.
2317        (h) The combination of options -rh failed to suppress file names for files
2318            that were found from directory arguments.
2320        (i) Added the -D (--devices) and -d (--directories) options.
2322        (j) Added the -F (--fixed-strings) option.
2324        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2326        (l) Added the --colo(u)r option.
2328        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2329            is not present by default.
2331     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2332        items such as (?R) or (?1), when the recursion could match a number of
2333        alternatives. If it matched one of the alternatives, but subsequently,
2334        outside the recursion, there was a failure, the code tried to back up into
2335        the recursion. However, because of the way PCRE is implemented, this is not
2336        possible, and the result was an incorrect result from the match.
2338        In order to prevent this happening, the specification of recursion has
2339        been changed so that all such subpatterns are automatically treated as
2340        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2342     4. I had overlooked the fact that, in some locales, there are characters for
2343        which isalpha() is true but neither isupper() nor islower() are true. In
2344        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2345        and ordfeminine) are like this. This affected the treatment of \w and \W
2346        when they appeared in character classes, but not when they appeared outside
2347        a character class. The bit map for "word" characters is now created
2348        separately from the results of isalnum() instead of just taking it from the
2349        upper, lower, and digit maps. (Plus the underscore character, of course.)
2351     5. The above bug also affected the handling of POSIX character classes such as
2352        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2353        permanent tables. Instead, the bit maps for such a class were previously
2354        created as the appropriate unions of the upper, lower, and digit bitmaps.
2355        Now they are created by subtraction from the [[:word:]] class, which has
2356        its own bitmap.
2358     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2359        It is created by subtracting the vertical space characters (\x09, \x0a,
2360        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2361        subtraction was done in the overall bitmap for a character class, meaning
2362        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2363        be recognized. This bug has been fixed.
2365     7. Patches from the folks at Google:
2367          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2368          real life, but is still worth protecting against".
2370          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2371          regular expressions".
2373          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2374          have it.
2376          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2377          "configure" and the latter not, in order to fix a problem somebody had
2378          with compiling the Arg class on HP-UX.
2380          (e) Improve the error-handling of the C++ wrapper a little bit.
2382          (f) New tests for checking recursion limiting.
2384     8. The pcre_memmove() function, which is used only if the environment does not
2385        have a standard memmove() function (and is therefore rarely compiled),
2386        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2387        returning a result (though PCRE never actually uses the result).
2389     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2390        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2391        returned instead of calling malloc() with an overflowing number that would
2392        most likely cause subsequent chaos.
2394    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2396    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2397        with this option is matched, the nmatch and pmatch options of regexec() are
2398        ignored.
2400    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2401        provided in case anyone wants to the the POSIX interface with UTF-8
2402        strings.
2404    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2405        C++ linking (needed for some HP-UX environments).
2407    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2408        (unused parameter) and in the pcre_printint() function (omitted "default"
2409        switch label when the default is to do nothing).
2411    15. Added some code to make it possible, when PCRE is compiled as a C++
2412        library, to replace subject pointers for pcre_exec() with a smart pointer
2413        class, thus making it possible to process discontinuous strings.
2415    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2416        much the same function. They were added by different people who were trying
2417        to make PCRE easy to compile on non-Unix systems. It has been suggested
2418        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2419        for compiling on Windows systems. I have therefore replaced it with
2420        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2421        defaults to "extern" for C or "extern C" for C++, which works fine on
2422        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2423        SCOPE with something explicit in config.h. In addition:
2425        (a) pcreposix.h still had just "extern" instead of either of these macros;
2426            I have replaced it with PCRE_DATA_SCOPE.
2428        (b) Functions such as _pcre_xclass(), which are internal to the library,
2429            but external in the C sense, all had PCRE_EXPORT in their definitions.
2430            This is apparently wrong for the Windows case, so I have removed it.
2431            (It makes no difference on Unix-like systems.)
2433    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2434        of recursive calls to match(). This is different to MATCH_LIMIT because
2435        that limits the total number of calls to match(), not all of which increase
2436        the depth of recursion. Limiting the recursion depth limits the amount of
2437        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2438        when PCRE is compiled, and changed at run time. A patch from Google adds
2439        this functionality to the C++ interface.
2441    18. Changes to the handling of Unicode character properties:
2443        (a) Updated the table to Unicode 4.1.0.
2445        (b) Recognize characters that are not in the table as "Cn" (undefined).
2447        (c) I revised the way the table is implemented to a much improved format
2448            which includes recognition of ranges. It now supports the ranges that
2449            are defined in UnicodeData.txt, and it also amalgamates other
2450            characters into ranges. This has reduced the number of entries in the
2451            table from around 16,000 to around 3,000, thus reducing its size
2452            considerably. I realized I did not need to use a tree structure after
2453            all - a binary chop search is just as efficient. Having reduced the
2454            number of entries, I extended their size from 6 bytes to 8 bytes to
2455            allow for more data.
2457        (d) Added support for Unicode script names via properties such as \p{Han}.
2459    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2460        matching that character.
2462    20. When matching a repeated Unicode property with a minimum greater than zero,
2463        (for example \pL{2,}), PCRE could look past the end of the subject if it
2464        reached it while seeking the minimum number of characters. This could
2465        happen only if some of the characters were more than one byte long, because
2466        there is a check for at least the minimum number of bytes.
2468    21. Refactored the implementation of \p and \P so as to be more general, to
2469        allow for more different types of property in future. This has changed the
2470        compiled form incompatibly. Anybody with saved compiled patterns that use
2471        \p or \P will have to recompile them.
2473    22. Added "Any" and "L&" to the supported property types.
2475    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2476        but give a compile time error if the value is greater than 0xff.
2478    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2479        accidentally not being installed or uninstalled.
2481    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2482        made were to insert the current release number. This seemed silly, because
2483        it made things harder for people building PCRE on systems that don't run
2484        "configure". I have turned pcre.h into a distributed file, no longer built
2485        by "configure", with the version identification directly included. There is
2486        no longer a pcre.h.in file.
2488        However, this change necessitated a change to the pcre-config script as
2489        well. It is built from pcre-config.in, and one of the substitutions was the
2490        release number. I have updated configure.ac so that ./configure now finds
2491        the release number by grepping pcre.h.
2493    26. Added the ability to run the tests under valgrind.
2496    Version 6.4 05-Sep-05
2497    ---------------------
2499     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2500        "--" to be printed when multiple files were scanned, even when none of the
2501        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2502        consider it to be a bug, and have restored the previous behaviour.
2504     2. A couple of code tidies to get rid of compiler warnings.
2506     3. The pcretest program used to cheat by referring to symbols in the library
2507        whose names begin with _pcre_. These are internal symbols that are not
2508        really supposed to be visible externally, and in some environments it is
2509        possible to suppress them. The cheating is now confined to including
2510        certain files from the library's source, which is a bit cleaner.
2512     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2513        file's purpose clearer.
2515     5. Reorganized pcre_ucp_findchar().
2518    Version 6.3 15-Aug-05
2519    ---------------------
2521     1. The file libpcre.pc.in did not have general read permission in the tarball.
2523     2. There were some problems when building without C++ support:
2525        (a) If C++ support was not built, "make install" and "make test" still
2526            tried to test it.
2528        (b) There were problems when the value of CXX was explicitly set. Some
2529            changes have been made to try to fix these, and ...
2531        (c) --disable-cpp can now be used to explicitly disable C++ support.
2533        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2534            backslash in a target when C++ was disabled. This confuses some
2535            versions of "make", apparently. Using an intermediate variable solves
2536            this. (Same for CPP_LOBJ.)
2538     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2539        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2540        necessary on certain architectures.
2542     4. Added a setting of -export-symbols-regex to the link command to remove
2543        those symbols that are exported in the C sense, but actually are local
2544        within the library, and not documented. Their names all begin with
2545        "_pcre_". This is not a perfect job, because (a) we have to except some
2546        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2547        available (and never for static libraries). I have made a note to try to
2548        find a way round (a) in the future.
2551    Version 6.2 01-Aug-05
2552    ---------------------
2554     1. There was no test for integer overflow of quantifier values. A construction
2555        such as {1111111111111111} would give undefined results. What is worse, if
2556        a minimum quantifier for a parenthesized subpattern overflowed and became
2557        negative, the calculation of the memory size went wrong. This could have
2558        led to memory overwriting.
2560     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2562     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2563        operating environments where this matters.
2565     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2566        PCRE options from within the C++ wrapper.
2568     5. Named capturing subpatterns were not being correctly counted when a pattern
2569        was compiled. This caused two problems: (a) If there were more than 100
2570        such subpatterns, the calculation of the memory needed for the whole
2571        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2572        back references of the form \12, where the number was greater than 9, were
2573        not recognized as back references, even though there were sufficient
2574        previous subpatterns.
2576     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2577        versions of gcc, e.g. 2.95.4.
2580    Version 6.1 21-Jun-05
2581    ---------------------
2583     1. There was one reference to the variable "posix" in pcretest.c that was not
2584        surrounded by "#if !defined NOPOSIX".
2586     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2587        the cross-check on the old pcre_info() function, for the benefit of the
2588        cut-down version of PCRE that is currently imported into Exim.
2590     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2591        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2592        patterns that start (?i) but I don't think that matters. The use of (?i) is
2593        just an example; this all applies to the other options as well.
2595     4. Since libtool seems to echo the compile commands it is issuing, the output
2596        from "make" can be reduced a bit by putting "@" in front of each libtool
2597        compile command.
2599     5. Patch from the folks at Google for configure.in to be a bit more thorough
2600        in checking for a suitable C++ installation before trying to compile the
2601        C++ stuff. This should fix a reported problem when a compiler was present,
2602        but no suitable headers.
2604     6. The man pages all had just "PCRE" as their title. I have changed them to
2605        be the relevant file name. I have also arranged that these names are
2606        retained in the file doc/pcre.txt, which is a concatenation in text format
2607        of all the man pages except the little individual ones for each function.
2609     7. The NON-UNIX-USE file had not been updated for the different set of source
2610        files that come with release 6. I also added a few comments about the C++
2611        wrapper.
2614    Version 6.0 07-Jun-05
2615    ---------------------
2617     1. Some minor internal re-organization to help with my DFA experiments.
2619     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2620        didn't matter for the library itself when fully configured, but did matter
2621        when compiling without UCP support, or within Exim, where the ucp files are
2622        not imported.
2624     3. Refactoring of the library code to split up the various functions into
2625        different source modules. The addition of the new DFA matching code (see
2626        below) to a single monolithic source would have made it really too
2627        unwieldy, quite apart from causing all the code to be include in a
2628        statically linked application, when only some functions are used. This is
2629        relevant even without the DFA addition now that patterns can be compiled in
2630        one application and matched in another.
2632        The downside of splitting up is that there have to be some external
2633        functions and data tables that are used internally in different modules of
2634        the library but which are not part of the API. These have all had their
2635        names changed to start with "_pcre_" so that they are unlikely to clash
2636        with other external names.
2638     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2639        a different (DFA) algorithm. Although it is slower than the original
2640        function, it does have some advantages for certain types of matching
2641        problem.
2643     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2644        including restarting after a partial match.
2646     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2647        defined when compiling for Windows was sent to me. I have put it into the
2648        code, though I have no means of testing or verifying it.
2650     7. Added the pcre_refcount() auxiliary function.
2652     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2653        match before or at the first newline in the subject string. In pcretest,
2654        the /f option on a pattern can be used to set this.
2656     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2657        would behave wrongly. This has been present in PCRE since release 4.0.
2659    10. A number of changes to the pcregrep command:
2661        (a) Refactored how -x works; insert ^(...)$ instead of setting
2662            PCRE_ANCHORED and checking the length, in preparation for adding
2663            something similar for -w.
2665        (b) Added the -w (match as a word) option.
2667        (c) Refactored the way lines are read and buffered so as to have more
2668            than one at a time available.
2670        (d) Implemented a pcregrep test script.
2672        (e) Added the -M (multiline match) option. This allows patterns to match
2673            over several lines of the subject. The buffering ensures that at least
2674            8K, or the rest of the document (whichever is the shorter) is available
2675            for matching (and similarly the previous 8K for lookbehind assertions).
2677        (f) Changed the --help output so that it now says
2679              -w, --word-regex(p)
2681            instead of two lines, one with "regex" and the other with "regexp"
2682            because that confused at least one person since the short forms are the
2683            same. (This required a bit of code, as the output is generated
2684            automatically from a table. It wasn't just a text change.)
2686        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2687            option but starts with a hyphen. Could be a pattern or a path name
2688            starting with a hyphen, for instance.
2690        (h) "-" can be given as a file name to represent stdin.
2692        (i) When file names are being printed, "(standard input)" is used for
2693            the standard input, for compatibility with GNU grep. Previously
2694            "<stdin>" was used.
2696        (j) The option --label=xxx can be used to supply a name to be used for
2697            stdin when file names are being printed. There is no short form.
2699        (k) Re-factored the options decoding logic because we are going to add
2700            two more options that take data. Such options can now be given in four
2701            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2703        (l) Added the -A, -B, and -C options for requesting that lines of context
2704            around matches be printed.
2706        (m) Added the -L option to print the names of files that do not contain
2707            any matching lines, that is, the complement of -l.
2709        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2710            continue to scan other files.
2712        (o) The -s option was incorrectly implemented. For compatibility with other
2713            greps, it now suppresses the error message for a non-existent or non-
2714            accessible file (but not the return code). There is a new option called
2715            -q that suppresses the output of matching lines, which was what -s was
2716            previously doing.
2718        (p) Added --include and --exclude options to specify files for inclusion
2719            and exclusion when recursing.
2721    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2722        Hopefully, it now does.
2724    12. Missing cast in pcre_study().
2726    13. Added an "uninstall" target to the makefile.
2728    14. Replaced "extern" in the function prototypes in Makefile.in with
2729        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2730        world, but is set differently for Windows.
2732    15. Added a second compiling function called pcre_compile2(). The only
2733        difference is that it has an extra argument, which is a pointer to an
2734        integer error code. When there is a compile-time failure, this is set
2735        non-zero, in addition to the error test pointer being set to point to an
2736        error message. The new argument may be NULL if no error number is required
2737        (but then you may as well call pcre_compile(), which is now just a
2738        wrapper). This facility is provided because some applications need a
2739        numeric error indication, but it has also enabled me to tidy up the way
2740        compile-time errors are handled in the POSIX wrapper.
2742    16. Added VPATH=.libs to the makefile; this should help when building with one
2743        prefix path and installing with another. (Or so I'm told by someone who
2744        knows more about this stuff than I do.)
2746    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2747        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2748        match everything, including newlines. This is not POSIX-compatible, but
2749        somebody wanted the feature. From pcretest it can be activated by using
2750        both the P and the s flags.
2752    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2754    19. libpcre.pc was being incorrectly installed as executable.
2756    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2757        it now also looks for '\r' so that it will work unmodified on Windows.
2759    21. Added Google's contributed C++ wrapper to the distribution.
2761    22. Added some untidy missing memory free() calls in pcretest, to keep
2762        Electric Fence happy when testing.
2766    Version 5.0 13-Sep-04
2767    ---------------------
2769     1. Internal change: literal characters are no longer packed up into items
2770        containing multiple characters in a single byte-string. Each character
2771        is now matched using a separate opcode. However, there may be more than one
2772        byte in the character in UTF-8 mode.
2774     2. The pcre_callout_block structure has two new fields: pattern_position and
2775        next_item_length. These contain the offset in the pattern to the next match
2776        item, and its length, respectively.
2778     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2779        insertion of callouts before each pattern item. Added the /C option to
2780        pcretest to make use of this.
2782     4. On the advice of a Windows user, the lines
2784          #if defined(_WIN32) || defined(WIN32)
2785          _setmode( _fileno( stdout ), 0x8000 );
2786          #endif  /* defined(_WIN32) || defined(WIN32) */
2788        have been added to the source of pcretest. This apparently does useful
2789        magic in relation to line terminators.
2791     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2792        for the benefit of those environments where the "b" makes a difference.
2794     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2795        to know about it. I have put a hack into configure.in that adds in code
2796        to set GCC=yes if CC=icc. This seems to end up at a point in the
2797        generated configure script that is early enough to affect the setting of
2798        compiler options, which is what is needed, but I have no means of testing
2799        whether it really works. (The user who reported this had patched the
2800        generated configure script, which of course I cannot do.)
2802        LATER: After change 22 below (new libtool files), the configure script
2803        seems to know about icc (and also ecc). Therefore, I have commented out
2804        this hack in configure.in.
2806     7. Added support for pkg-config (2 patches were sent in).
2808     8. Negated POSIX character classes that used a combination of internal tables
2809        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2810        [[:^ascii]]. Typically, they would match almost any characters. The other
2811        POSIX classes were not broken in this way.
2813     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2814        to find the match, as PCRE was deluded into thinking that the match had to
2815        start at the start point or following a newline. The same bug applied to
2816        patterns with negative forward assertions or any backward assertions
2817        preceding ".*" at the start, unless the pattern required a fixed first
2818        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2820    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2821        starting at the last subject character, bytes beyond the end of the subject
2822        string were read.
2824    11. Renamed the variable "class" as "classbits" to make life easier for C++
2825        users. (Previously there was a macro definition, but it apparently wasn't
2826        enough.)
2828    12. Added the new field "tables" to the extra data so that tables can be passed
2829        in at exec time, or the internal tables can be re-selected. This allows
2830        a compiled regex to be saved and re-used at a later time by a different
2831        program that might have everything at different addresses.
2833    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2834        -R library as well as a -L library.
2836    14. The debugging options of pcretest (-d on the command line or D on a
2837        pattern) showed incorrect output for anything following an extended class
2838        that contained multibyte characters and which was followed by a quantifier.
2840    15. Added optional support for general category Unicode character properties
2841        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2842        support. It adds about 90K to the size of the library. The meanings of the
2843        inbuilt class escapes such as \d and \s have NOT been changed.
2845    16. Updated pcredemo.c to include calls to free() to release the memory for the
2846        compiled pattern.
2848    17. The generated file chartables.c was being created in the source directory
2849        instead of in the building directory. This caused the build to fail if the
2850        source directory was different from the building directory, and was
2851        read-only.
2853    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2854        file. No doubt somebody will tell me if they don't make sense... Also added
2855        Dan Mooney's comments about building on OpenVMS.
2857    19. Added support for partial matching via the PCRE_PARTIAL option for
2858        pcre_exec() and the \P data escape in pcretest.
2860    20. Extended pcretest with 3 new pattern features:
2862        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2863              write the compiled pattern to the file whose name is "rest-of-line".
2864              This is a straight binary dump of the data, with the saved pointer to
2865              the character tables forced to be NULL. The study data, if any, is
2866              written too. After writing, pcretest reads a new pattern.
2868        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2869              compiled pattern from the given file. There must not be any
2870              occurrences of "<" in the file name (pretty unlikely); if there are,
2871              pcretest will instead treat the initial "<" as a pattern delimiter.
2872              After reading in the pattern, pcretest goes on to read data lines as
2873              usual.
2875        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2876              and 16-bit fields in a compiled pattern, to simulate a pattern that
2877              was compiled on a host of opposite endianness.
2879    21. The pcre-exec() function can now cope with patterns that were compiled on
2880        hosts of opposite endianness, with this restriction:
2882          As for any compiled expression that is saved and used later, the tables
2883          pointer field cannot be preserved; the extra_data field in the arguments
2884          to pcre_exec() should be used to pass in a tables address if a value
2885          other than the default internal tables were used at compile time.
2887    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2888        now diagnosed as an error. Previously, most of the time, a negative number
2889        would have been treated as zero, but if in addition "ovector" was passed as
2890        NULL, a crash could occur.
2892    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2893        new versions from the libtool 1.5 distribution (the last one is a copy of
2894        a file called libtool.m4). This seems to have fixed the need to patch
2895        "configure" to support Darwin 1.3 (which I used to do). However, I still
2896        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2897        workstation).
2899    24. Changed the PCRE licence to be the more standard "BSD" licence.
2902    Version 4.5 01-Dec-03
2903    ---------------------
2905     1. There has been some re-arrangement of the code for the match() function so
2906        that it can be compiled in a version that does not call itself recursively.
2907        Instead, it keeps those local variables that need separate instances for
2908        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2909        needs to "recurse". Keeping track of where control must go is done by means
2910        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2911        hide most of the details from the main code, and operates only if
2912        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2913        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2914        operating.
2916        To make it easier for callers to provide specially tailored get/free
2917        functions for this usage, two new functions, pcre_stack_malloc, and
2918        pcre_stack_free, are used. They are always called in strict stacking order,
2919        and the size of block requested is always the same.
2921        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2922        PCRE has been compiled to use the stack or the heap for recursion. The
2923        -C option of pcretest uses this to show which version is compiled.
2925        A new data escape \S, is added to pcretest; it causes the amounts of store
2926        obtained and freed by both kinds of malloc/free at match time to be added
2927        to the output.
2929     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2930        what's available on my current Linux desktop machine.
2932     3. When matching a UTF-8 string, the test for a valid string at the start has
2933        been extended. If start_offset is not zero, PCRE now checks that it points
2934        to a byte that is the start of a UTF-8 character. If not, it returns
2935        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2936        this is necessary because there may be backward assertions in the pattern.
2937        When matching the same subject several times, it may save resources to use
2938        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2940     4. The code for checking the validity of UTF-8 strings has been tightened so
2941        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2942        containing "overlong sequences".
2944     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2945        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2946        should have been "&", but it just so happened that all the cases this let
2947        through by mistake were picked up later in the function.
2949     6. I had used a variable called "isblank" - this is a C99 function, causing
2950        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2952     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2953        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2954        so the version is shown; (c) stop "make test" echoing "./RunTest".
2956     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2958     9. The prototype for memmove() for systems that don't have it was using
2959        size_t, but the inclusion of the header that defines size_t was later. I've
2960        moved the #includes for the C headers earlier to avoid this.
2962    10. Added some adjustments to the code to make it easier to compiler on certain
2963        special systems:
2965          (a) Some "const" qualifiers were missing.
2966          (b) Added the macro EXPORT before all exported functions; by default this
2967              is defined to be empty.
2968          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2969              that it reads its output file name as an argument instead of writing
2970              to the standard output and assuming this can be redirected.
2972    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2973        class containing characters with values greater than 255, PCRE compilation
2974        went into a loop.
2976    12. A recursive reference to a subpattern that was within another subpattern
2977        that had a minimum quantifier of zero caused PCRE to crash. For example,
2978        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2979        recursion. If the recursively-called subpattern itself had a zero repeat,
2980        that was OK.
2982    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2983        buffer into which it was copied (for escape processing) was still set at
2984        1024, so long lines caused crashes.
2986    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2987        "internal error: code overflow...". This applied to any character class
2988        that was followed by a possessive quantifier.
2990    15. Modified the Makefile to add libpcre.la as a prerequisite for
2991        libpcreposix.la because I was told this is needed for a parallel build to
2992        work.
2994    16. If a pattern that contained .* following optional items at the start was
2995        studied, the wrong optimizing data was generated, leading to matching
2996        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2997        matching string must start with a or b or c. The correct conclusion for
2998        this pattern is that a match can start with any character.
3001    Version 4.4 13-Aug-03
3002    ---------------------
3004     1. In UTF-8 mode, a character class containing characters with values between
3005        127 and 255 was not handled correctly if the compiled pattern was studied.
3006        In fixing this, I have also improved the studying algorithm for such
3007        classes (slightly).
3009     2. Three internal functions had redundant arguments passed to them. Removal
3010        might give a very teeny performance improvement.
3012     3. Documentation bug: the value of the capture_top field in a callout is *one
3013        more than* the number of the hightest numbered captured substring.
3015     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
3016        in incorrectly linking with a previously installed version. They now link
3017        explicitly with libpcre.la.
3019     5. configure.in no longer needs to recognize Cygwin specially.
3021     6. A problem in pcre.in for Windows platforms is fixed.
3023     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
3024        pcretest, it used to include the size of the study block as part of its
3025        output. Unfortunately, the structure contains a field that has a different
3026        size on different hardware architectures. This meant that the tests that
3027        showed this size failed. As the block is currently always of a fixed size,
3028        this information isn't actually particularly useful in pcretest output, so
3029        I have just removed it.
3031     8. Three pre-processor statements accidentally did not start in column 1.
3032        Sadly, there are *still* compilers around that complain, even though
3033        standard C has not required this for well over a decade. Sigh.
3035     9. In pcretest, the code for checking callouts passed small integers in the
3036        callout_data field, which is a void * field. However, some picky compilers
3037        complained about the casts involved for this on 64-bit systems. Now
3038        pcretest passes the address of the small integer instead, which should get
3039        rid of the warnings.
3041    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
3042        both compile and run time, and gives an error if an invalid UTF-8 sequence
3043        is found. There is a option for disabling this check in cases where the
3044        string is known to be correct and/or the maximum performance is wanted.
3046    11. In response to a bug report, I changed one line in Makefile.in from
3048            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
3049        to
3050            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
3052        to look similar to other lines, but I have no way of telling whether this
3053        is the right thing to do, as I do not use Windows. No doubt I'll get told
3054        if it's wrong...
3057  Version 4.3 21-May-03  Version 4.3 21-May-03
3058  ---------------------  ---------------------

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