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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.13 30-Apr-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, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
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 *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
176    33. Previously, PCRE did not allow quantification of assertions. However, Perl
177        does, and because of capturing effects, quantifying parenthesized
178        assertions may at times be useful. Quantifiers are now allowed for
179        parenthesized assertions.
181    34. A minor code tidy in pcre_compile() when checking options for \R usage.
183    35. \g was being checked for fancy things in a character class, when it should
184        just be a literal "g".
186    36. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
187        appearance of a nested POSIX class supersedes an apparent external class.
188        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
189        unescaped square brackets may also appear as part of class names. For
190        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
191        more like Perl.
193    37. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
194        was because it thought it was \N{name}, which is not supported).
196    38. Add minix to OS list not supporting the -S option in pcretest.
198    39. PCRE tries to detect cases of infinite recursion at compile time, but it
199        cannot analyze patterns in sufficient detail to catch mutual recursions
200        such as ((?1))((?2)). There is now a runtime test that gives an error if a
201        subgroup is called recursively as a subpattern for a second time at the
202        same position in the subject string. In previous releases this might have
203        been caught by the recursion limit, or it might have run out of stack.
205    40. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
206        happen only once. PCRE was, however incorrectly giving a compile time error
207        "recursive call could loop indefinitely" because it cannot analyze the
208        pattern in sufficient detail. The compile time test no longer happens when
209        PCRE is compiling a conditional subpattern, but actual runaway loops are
210        now caught at runtime (see 39 above).
212    41. It seems that Perl allows any characters other than a closing parenthesis
213        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
214        has been changed to be the same.
216    42. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
217        as not to get warnings when autogen.sh is called. Also changed
218        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
220    43. To help people who use pcregrep to scan files containing exceedingly long
221        lines, the following changes have been made:
223        (a) The default value of the buffer size parameter has been increased from
224            8K to 20K. (A buffer three times this size is actually used.)
226        (b) The default can be changed by ./configure --with-pcregrep-bufsiz when
227            PCRE is built.
229        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
230            to be set at run time.
232        (d) Numerical values in pcregrep options can be followed by K or M, for
233            example --buffer-size=50K.
235        (e) If a line being scanned overflows pcregrep's buffer, an error is now
236            given and the return code is set to 2.
238    44. Add a pointer to the latest mark to the callout data block.
240    45. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
241        partial match of an empty string instead of no match. This was specific to
242        the use of ".".
244    46. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
245        complete match instead of a partial match. This bug was dependent on both
246        the PCRE_UTF8 and PCRE_DOTALL options being set.
249    Version 8.12 15-Jan-2011
250    ------------------------
252    1.  Fixed some typos in the markup of the man pages, and wrote a script that
253        checks for such things as part of the documentation building process.
255    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
256        --match-limit and --recursion-limit options (added for 8.11). In
257        particular, this made one of the standard tests fail. (The integer value
258        went into the wrong half of a long int.)
260    3.  If the --colour option was given to pcregrep with -v (invert match), it
261        did strange things, either producing crazy output, or crashing. It should,
262        of course, ignore a request for colour when reporting lines that do not
263        match.
265    4.  Another pcregrep bug caused similar problems if --colour was specified with
266        -M (multiline) and the pattern match finished with a line ending.
268    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
269        matched in multiline mode, the following line was shown as part of the
270        match. This seems wrong, so I have changed it.
272    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
273        the check for further matches in the same line (so they could be coloured)
274        to overrun the end of the current line. If another match was found, it was
275        incorrectly shown (and then shown again when found in the next line).
277    7.  If pcregrep was compiled under Windows, there was a reference to the
278        function pcregrep_exit() before it was defined. I am assuming this was
279        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
280        reported by a user. I've moved the definition above the reference.
283    Version 8.11 10-Dec-2010
284    ------------------------
286    1.  (*THEN) was not working properly if there were untried alternatives prior
287        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
288        backtracked to try for "b" instead of moving to the next alternative branch
289        at the same level (in this case, to look for "c"). The Perl documentation
290        is clear that when (*THEN) is backtracked onto, it goes to the "next
291        alternative in the innermost enclosing group".
293    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
294        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
295        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
296        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
297        (*THEN).
299    3.  If \s appeared in a character class, it removed the VT character from
300        the class, even if it had been included by some previous item, for example
301        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
302        of \s, but is part of the POSIX "space" class.)
304    4.  A partial match never returns an empty string (because you can always
305        match an empty string at the end of the subject); however the checking for
306        an empty string was starting at the "start of match" point. This has been
307        changed to the "earliest inspected character" point, because the returned
308        data for a partial match starts at this character. This means that, for
309        example, /(?<=abc)def/ gives a partial match for the subject "abc"
310        (previously it gave "no match").
312    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
313        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
314        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
315        has an implication that the given string is incomplete (because a partial
316        match is preferred over a full match). For this reason, these items now
317        give a partial match in this situation. [Aside: previously, the one case
318        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
319        match rather than a full match, which was wrong by the old rules, but is
320        now correct.]
322    6.  There was a bug in the handling of #-introduced comments, recognized when
323        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
324        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
325        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
326        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
327        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
328        places in pcre_compile().
330    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
331        comments when looking ahead for named forward references to subpatterns,
332        the only newline sequence it recognized was NL. It now handles newlines
333        according to the set newline convention.
335    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
336        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
337        cater for a lack of strerror(). These oversights have been fixed.
339    9.  Added --match-limit and --recursion-limit to pcregrep.
341    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
343    11. When the -o option was used, pcregrep was setting a return code of 1, even
344        when matches were found, and --line-buffered was not being honoured.
346    12. Added an optional parentheses number to the -o and --only-matching options
347        of pcregrep.
349    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
350        can match an empty string. The code to do it in pcretest and pcredemo
351        needed fixing:
353        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
354            only one byte after an empty string match just before CRLF (this case
355            just got forgotten; "any" and "anycrlf" were OK).
357        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
358            mode when an empty string match preceded an ASCII character followed by
359            a non-ASCII character. (The code for advancing by one character rather
360            than one byte was nonsense.)
362        (c) The pcredemo.c sample program did not have any code at all to handle
363            the cases when CRLF is a valid newline sequence.
365    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
366        as a starting offset was within the subject string. There is now a new
367        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
368        negative or greater than the length of the string. In order to test this,
369        pcretest is extended to allow the setting of negative starting offsets.
371    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
372        starting offset points to the beginning of a UTF-8 character was
373        unnecessarily clumsy. I tidied it up.
375    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
376        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
378    17. Nobody had reported that the --include_dir option, which was added in
379        release 7.7 should have been called --include-dir (hyphen, not underscore)
380        for compatibility with GNU grep. I have changed it to --include-dir, but
381        left --include_dir as an undocumented synonym, and the same for
382        --exclude-dir, though that is not available in GNU grep, at least as of
383        release 2.5.4.
385    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
386        characters from a string of bytes) have been redefined so as not to use
387        loops, in order to improve performance in some environments. At the same
388        time, I abstracted some of the common code into auxiliary macros to save
389        repetition (this should not affect the compiled code).
391    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
392        compile-time error is now given if \c is not followed by an ASCII
393        character, that is, a byte less than 128. (In EBCDIC mode, the code is
394        different, and any byte value is allowed.)
396    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
397        START_OPTIMIZE option, which is now allowed at compile time - but just
398        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
399        to pcregrep and other applications that have no direct access to PCRE
400        options. The new /Y option in pcretest sets this option when calling
401        pcre_compile().
403    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
404        back references. Groups containing recursive back references were forced to
405        be atomic by that change, but in the case of named groups, the amount of
406        memory required was incorrectly computed, leading to "Failed: internal
407        error: code overflow". This has been fixed.
409    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
410        pcretest.c, to avoid build problems in some Borland environments.
413    Version 8.10 25-Jun-2010
414    ------------------------
416    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
417        THEN.
419    2.  (*ACCEPT) was not working when inside an atomic group.
421    3.  Inside a character class, \B is treated as a literal by default, but
422        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
423        causes the error). The code is unchanged, but I tidied the documentation.
425    4.  Inside a character class, PCRE always treated \R and \X as literals,
426        whereas Perl faults them if its -w option is set. I have changed PCRE so
427        that it faults them when PCRE_EXTRA is set.
429    5.  Added support for \N, which always matches any character other than
430        newline. (It is the same as "." when PCRE_DOTALL is not set.)
432    6.  When compiling pcregrep with newer versions of gcc which may have
433        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
434        declared with attribute warn_unused_result" were given. Just casting the
435        result to (void) does not stop the warnings; a more elaborate fudge is
436        needed. I've used a macro to implement this.
438    7.  Minor change to pcretest.c to avoid a compiler warning.
440    8.  Added four artifical Unicode properties to help with an option to make
441        \s etc use properties (see next item). The new properties are: Xan
442        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
444    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
445        use Unicode properties. (*UCP) at the start of a pattern can be used to set
446        this option. Modified pcretest to add /W to test this facility. Added
447        REG_UCP to make it available via the POSIX interface.
449    10. Added --line-buffered to pcregrep.
451    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
452        studied, and the match started with a letter with a code point greater than
453        127 whose first byte was different to the first byte of the other case of
454        the letter, the other case of this starting letter was not recognized
455        (#976).
457    12. If a pattern that was studied started with a repeated Unicode property
458        test, for example, \p{Nd}+, there was the theoretical possibility of
459        setting up an incorrect bitmap of starting bytes, but fortunately it could
460        not have actually happened in practice until change 8 above was made (it
461        added property types that matched character-matching opcodes).
463    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
464        possible starting bytes for non-anchored patterns.
466    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
467        \R, and also a number of cases that involve Unicode properties, both
468        explicit and implicit when PCRE_UCP is set.
470    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
471        input, it could crash or give wrong results if characters with values
472        greater than 0xc0 were present in the subject string. (Detail: it assumed
473        UTF-8 input when processing these items.)
475    16. Added a lot of (int) casts to avoid compiler warnings in systems where
476        size_t is 64-bit (#991).
478    17. Added a check for running out of memory when PCRE is compiled with
479        --disable-stack-for-recursion (#990).
481    18. If the last data line in a file for pcretest does not have a newline on
482        the end, a newline was missing in the output.
484    19. The default pcre_chartables.c file recognizes only ASCII characters (values
485        less than 128) in its various bitmaps. However, there is a facility for
486        generating tables according to the current locale when PCRE is compiled. It
487        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
488        characters, are recognized by isspace() and therefore were getting set in
489        these tables, and indeed these tables seem to approximate to ISO 8859. This
490        caused a problem in UTF-8 mode when pcre_study() was used to create a list
491        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
492        which of course cannot start UTF-8 characters. I have changed the code so
493        that only real ASCII characters (less than 128) and the correct starting
494        bytes for UTF-8 encodings are set for characters greater than 127 when in
495        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
496        altogether.)
498    20. Added the /T option to pcretest so as to be able to run tests with non-
499        standard character tables, thus making it possible to include the tests
500        used for 19 above in the standard set of tests.
502    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
503        reference to a subpattern the other side of a comment that contains an
504        opening parenthesis caused either an internal compiling error, or a
505        reference to the wrong subpattern.
508    Version 8.02 19-Mar-2010
509    ------------------------
511    1.  The Unicode data tables have been updated to Unicode 5.2.0.
513    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
514        configured.
516    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
517        original author of that file, following a query about its status.
519    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
520        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
522    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
523        quantifier applied to a forward-referencing subroutine call, could compile
524        incorrect code or give the error "internal error: previously-checked
525        referenced subpattern not found".
527    6.  Both MS Visual Studio and Symbian OS have problems with initializing
528        variables to point to external functions. For these systems, therefore,
529        pcre_malloc etc. are now initialized to local functions that call the
530        relevant global functions.
532    7.  There were two entries missing in the vectors called coptable and poptable
533        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
534        I've fixed the data, and added a kludgy way of testing at compile time that
535        the lengths are correct (equal to the number of opcodes).
537    8.  Following on from 7, I added a similar kludge to check the length of the
538        eint vector in pcreposix.c.
540    9.  Error texts for pcre_compile() are held as one long string to avoid too
541        much relocation at load time. To find a text, the string is searched,
542        counting zeros. There was no check for running off the end of the string,
543        which could happen if a new error number was added without updating the
544        string.
546    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
548    11. \K was not working if it appeared in an atomic group or in a group that
549        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
550        \K is "not well defined" if used in an assertion. PCRE now accepts it if
551        the assertion is positive, but not if it is negative.
553    12. Change 11 fortuitously reduced the size of the stack frame used in the
554        "match()" function of pcre_exec.c by one pointer. Forthcoming
555        implementation of support for (*MARK) will need an extra pointer on the
556        stack; I have reserved it now, so that the stack frame size does not
557        decrease.
559    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
560        item in branch that calls a recursion is a subroutine call - as in the
561        second branch in the above example - was incorrectly given the compile-
562        time error "recursive call could loop indefinitely" because pcre_compile()
563        was not correctly checking the subroutine for matching a non-empty string.
565    14. The checks for overrunning compiling workspace could trigger after an
566        overrun had occurred. This is a "should never occur" error, but it can be
567        triggered by pathological patterns such as hundreds of nested parentheses.
568        The checks now trigger 100 bytes before the end of the workspace.
570    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
573    Version 8.01 19-Jan-2010
574    ------------------------
576    1.  If a pattern contained a conditional subpattern with only one branch (in
577        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
578        computed the wrong minimum data length (which is of course zero for such
579        subpatterns). This could cause incorrect "no match" results.
581    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
582        the pattern is reset in the first branch, pcre_compile() failed with
583        "internal error: code overflow at offset...". This happened only when
584        the reset was to the original external option setting. (An optimization
585        abstracts leading options settings into an external setting, which was the
586        cause of this.)
588    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
589        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
590        assertion pattern did not match (meaning that the assertion was true), it
591        was incorrectly treated as false if the SKIP had been reached during the
592        matching. This also applied to assertions used as conditions.
594    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
595        assertion subpattern, including such a pattern used as a condition,
596        unpredictable results occurred, instead of the error return
599    5.  The C++ GlobalReplace function was not working like Perl for the special
600        situation when an empty string is matched. It now does the fancy magic
601        stuff that is necessary.
603    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
604        removed. (These were left over from very, very early versions of PCRE.)
606    7.  Some cosmetic changes to the code to make life easier when compiling it
607        as part of something else:
609        (a) Change DEBUG to PCRE_DEBUG.
611        (b) In pcre_compile(), rename the member of the "branch_chain" structure
612            called "current" as "current_branch", to prevent a collision with the
613            Linux macro when compiled as a kernel module.
615        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
616            prevent a collision with the Linux macro when compiled as a kernel
617            module.
619    8.  In pcre_compile() there are some checks for integer overflows that used to
620        cast potentially large values to (double). This has been changed to that
621        when building, a check for int64_t is made, and if it is found, it is used
622        instead, thus avoiding the use of floating point arithmetic. (There is no
623        other use of FP in PCRE.) If int64_t is not found, the fallback is to
624        double.
626    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
627        2005 (difference between two addresses compared to an unsigned value).
629    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
630        custom one, because of the following reported problem in Windows:
632          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
633              under Win32.
634          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
635              therefore missing the function definition.
636          - The compiler thus generates a "C" signature for the test function.
637          - The linker fails to find the "C" function.
638          - PCRE fails to configure if asked to do so against libbz2.
640    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
641        messages were output:
643          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
644          rerunning libtoolize, to keep the correct libtool macros in-tree.
645          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
647        I have done both of these things.
649    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
650        most of the time, it *can* run out if it is given a pattern that contains a
651        runaway infinite recursion. I updated the discussion in the pcrestack man
652        page.
654    13. Now that we have gone to the x.xx style of version numbers, the minor
655        version may start with zero. Using 08 or 09 is a bad idea because users
656        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
657        interpreted as invalid octal numbers. I've updated the previous comment in
658        configure.ac, and also added a check that gives an error if 08 or 09 are
659        used.
661    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
662        causing partial matching to fail when the end of the subject matched \W
663        in a UTF-8 pattern where \W was quantified with a minimum of 3.
665    15. There were some discrepancies between the declarations in pcre_internal.h
666        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
667        their definitions. The declarations used "const uschar *" and the
668        definitions used USPTR. Even though USPTR is normally defined as "const
669        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
670        reported that: "This difference in casting confuses some C++ compilers, for
671        example, SunCC recognizes above declarations as different functions and
672        generates broken code for hbpcre." I have changed the declarations to use
673        USPTR.
675    16. GNU libtool is named differently on some systems. The autogen.sh script now
676        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
677        (FreeBSD).
679    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
680        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
681        comment: "Figure out how to create a longlong from a string: strtoll and
682        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
683        instance, but it only takes 2 args instead of 3!"
685    18. A subtle bug concerned with back references has been fixed by a change of
686        specification, with a corresponding code fix. A pattern such as
687        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
688        refers, was giving matches when it shouldn't. For example, xa=xaaa would
689        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
690        same bug. Such groups have to be quantified to be useful, or contained
691        inside another quantified group. (If there's no repetition, the reference
692        can never match.) The problem arises because, having left the group and
693        moved on to the rest of the pattern, a later failure that backtracks into
694        the group uses the captured value from the final iteration of the group
695        rather than the correct earlier one. I have fixed this in PCRE by forcing
696        any group that contains a reference to itself to be an atomic group; that
697        is, there cannot be any backtracking into it once it has completed. This is
698        similar to recursive and subroutine calls.
701    Version 8.00 19-Oct-09
702    ----------------------
704    1.  The table for translating pcre_compile() error codes into POSIX error codes
705        was out-of-date, and there was no check on the pcre_compile() error code
706        being within the table. This could lead to an OK return being given in
707        error.
709    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
710        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
711        in a Windows environment.
713    3.  The pcregrep --count option prints the count for each file even when it is
714        zero, as does GNU grep. However, pcregrep was also printing all files when
715        --files-with-matches was added. Now, when both options are given, it prints
716        counts only for those files that have at least one match. (GNU grep just
717        prints the file name in this circumstance, but including the count seems
718        more useful - otherwise, why use --count?) Also ensured that the
719        combination -clh just lists non-zero counts, with no names.
721    4.  The long form of the pcregrep -F option was incorrectly implemented as
722        --fixed_strings instead of --fixed-strings. This is an incompatible change,
723        but it seems right to fix it, and I didn't think it was worth preserving
724        the old behaviour.
726    5.  The command line items --regex=pattern and --regexp=pattern were not
727        recognized by pcregrep, which required --regex pattern or --regexp pattern
728        (with a space rather than an '='). The man page documented the '=' forms,
729        which are compatible with GNU grep; these now work.
731    6.  No libpcreposix.pc file was created for pkg-config; there was just
732        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
734    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
735        when UCP support is not needed, by modifying the Python script that
736        generates it from Unicode data files. This should not matter if the module
737        is correctly used as a library, but I received one complaint about 50K of
738        unwanted data. My guess is that the person linked everything into his
739        program rather than using a library. Anyway, it does no harm.
741    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
742        was a minimum greater than 1 for a wide character in a possessive
743        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
744        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
745        character. Chaos in the form of incorrect output or a compiling loop could
746        result.
748    9.  The restrictions on what a pattern can contain when partial matching is
749        requested for pcre_exec() have been removed. All patterns can now be
750        partially matched by this function. In addition, if there are at least two
751        slots in the offset vector, the offset of the earliest inspected character
752        for the match and the offset of the end of the subject are set in them when
753        PCRE_ERROR_PARTIAL is returned.
755    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
756        synonymous with PCRE_PARTIAL, for backwards compatibility, and
757        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
758        and may be more useful for multi-segment matching.
760    11. Partial matching with pcre_exec() is now more intuitive. A partial match
761        used to be given if ever the end of the subject was reached; now it is
762        given only if matching could not proceed because another character was
763        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
764        string "Z", which now yields "no match" instead of "partial match". In the
765        case of pcre_dfa_exec(), "no match" is given if every matching path for the
766        final character ended with (*FAIL).
768    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
769        if the pattern had a "must contain" character that was already found in the
770        earlier partial match, unless partial matching was again requested. For
771        example, with the pattern /dog.(body)?/, the "must contain" character is
772        "g". If the first part-match was for the string "dog", restarting with
773        "sbody" failed. This bug has been fixed.
775    13. The string returned by pcre_dfa_exec() after a partial match has been
776        changed so that it starts at the first inspected character rather than the
777        first character of the match. This makes a difference only if the pattern
778        starts with a lookbehind assertion or \b or \B (\K is not supported by
779        pcre_dfa_exec()). It's an incompatible change, but it makes the two
780        matching functions compatible, and I think it's the right thing to do.
782    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
783        so that the demonstration program is easily available in environments where
784        PCRE has not been installed from source.
786    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
787        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
788        library.
790    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
791        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
792        is not the first non-POSIX option to be added. Clearly some people find
793        these options useful.
795    17. If a caller to the POSIX matching function regexec() passes a non-zero
796        value for nmatch with a NULL value for pmatch, the value of
797        nmatch is forced to zero.
799    18. RunGrepTest did not have a test for the availability of the -u option of
800        the diff command, as RunTest does. It now checks in the same way as
801        RunTest, and also checks for the -b option.
803    19. If an odd number of negated classes containing just a single character
804        interposed, within parentheses, between a forward reference to a named
805        subpattern and the definition of the subpattern, compilation crashed with
806        an internal error, complaining that it could not find the referenced
807        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
808        [The bug was that it was starting one character too far in when skipping
809        over the character class, thus treating the ] as data rather than
810        terminating the class. This meant it could skip too much.]
812    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
813        /g option in pcretest when the pattern contains \K, which makes it possible
814        to have an empty string match not at the start, even when the pattern is
815        anchored. Updated pcretest and pcredemo to use this option.
817    21. If the maximum number of capturing subpatterns in a recursion was greater
818        than the maximum at the outer level, the higher number was returned, but
819        with unset values at the outer level. The correct (outer level) value is
820        now given.
822    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
823        PCRE did not set those parentheses (unlike Perl). I have now found a way to
824        make it do so. The string so far is captured, making this feature
825        compatible with Perl.
827    23. The tests have been re-organized, adding tests 11 and 12, to make it
828        possible to check the Perl 5.10 features against Perl 5.10.
830    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
831        pattern matches a fixed length string. PCRE did not allow this; now it
832        does. Neither allows recursion.
834    25. I finally figured out how to implement a request to provide the minimum
835        length of subject string that was needed in order to match a given pattern.
836        (It was back references and recursion that I had previously got hung up
837        on.) This code has now been added to pcre_study(); it finds a lower bound
838        to the length of subject needed. It is not necessarily the greatest lower
839        bound, but using it to avoid searching strings that are too short does give
840        some useful speed-ups. The value is available to calling programs via
841        pcre_fullinfo().
843    26. While implementing 25, I discovered to my embarrassment that pcretest had
844        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
845        study optimizations had never been tested with that matching function.
846        Oops. What is worse, even when it was passed study data, there was a bug in
847        pcre_dfa_exec() that meant it never actually used it. Double oops. There
848        were also very few tests of studied patterns with pcre_dfa_exec().
850    27. If (?| is used to create subpatterns with duplicate numbers, they are now
851        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
852        on the other side of the coin, they are no longer allowed to have different
853        names, because these cannot be distinguished in PCRE, and this has caused
854        confusion. (This is a difference from Perl.)
856    28. When duplicate subpattern names are present (necessarily with different
857        numbers, as required by 27 above), and a test is made by name in a
858        conditional pattern, either for a subpattern having been matched, or for
859        recursion in such a pattern, all the associated numbered subpatterns are
860        tested, and the overall condition is true if the condition is true for any
861        one of them. This is the way Perl works, and is also more like the way
862        testing by number works.
865    Version 7.9 11-Apr-09
866    ---------------------
868    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
869        (pcretest), all targets were linked against these libraries. This included
870        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
871        libraries. This caused unwanted dependencies to be created. This problem
872        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
873        pcretest is linked with readline.
875    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
876        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
877        moved outside it again, because FALSE and TRUE are already defined in AIX,
878        but BOOL is not.
880    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
881        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
883    4.  The pcregrep documentation said spaces were inserted as well as colons (or
884        hyphens) following file names and line numbers when outputting matching
885        lines. This is not true; no spaces are inserted. I have also clarified the
886        wording for the --colour (or --color) option.
888    5.  In pcregrep, when --colour was used with -o, the list of matching strings
889        was not coloured; this is different to GNU grep, so I have changed it to be
890        the same.
892    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
893        each matching line was coloured. Now it goes on to look for further matches
894        of any of the test patterns, which is the same behaviour as GNU grep.
896    7.  A pattern that could match an empty string could cause pcregrep to loop; it
897        doesn't make sense to accept an empty string match in pcregrep, so I have
898        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
899        seems to be how GNU grep behaves.
901    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
902        start or after a newline", because the conditional assertion was not being
903        correctly handled. The rule now is that both the assertion and what follows
904        in the first alternative must satisfy the test.
906    9.  If auto-callout was enabled in a pattern with a conditional group whose
907        condition was an assertion, PCRE could crash during matching, both with
908        pcre_exec() and pcre_dfa_exec().
910    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
911        used for matching.
913    11. Unicode property support in character classes was not working for
914        characters (bytes) greater than 127 when not in UTF-8 mode.
916    12. Added the -M command line option to pcretest.
918    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
920    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
922    16. Added comments and documentation about mis-use of no_arg in the C++
923        wrapper.
925    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
926        from Martin Jerabek that uses macro names for all relevant character and
927        string constants.
929    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
930        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
931        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
932        these, but not everybody uses configure.
934    19. A conditional group that had only one branch was not being correctly
935        recognized as an item that could match an empty string. This meant that an
936        enclosing group might also not be so recognized, causing infinite looping
937        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
938        with the subject "ab", where knowledge that the repeated group can match
939        nothing is needed in order to break the loop.
941    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
942        exec(), but without supplying a callout function, matching went wrong.
944    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
945        leak if the size of the offset vector was greater than 30. When the vector
946        is smaller, the saved offsets during recursion go onto a local stack
947        vector, but for larger vectors malloc() is used. It was failing to free
948        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
949        error, in fact).
951    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
952        heapframe that is used only when UTF-8 support is enabled. This caused no
953        problem, but was untidy.
955    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
956        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
957        included within another project.
959    24. Steven Van Ingelgem's patches to add more options to the CMake support,
960        slightly modified by me:
962          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
963              not building pcregrep.
965          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
966              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
968    25. Forward references, both numeric and by name, in patterns that made use of
969        duplicate group numbers, could behave incorrectly or give incorrect errors,
970        because when scanning forward to find the reference group, PCRE was not
971        taking into account the duplicate group numbers. A pattern such as
972        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
974    26. Changed a few more instances of "const unsigned char *" to USPTR, making
975        the feature of a custom pointer more persuasive (as requested by a user).
977    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
978        pcretest.c, inside #ifndefs, because it seems they are sometimes already
979        pre-defined.
981    28. Added support for (*UTF8) at the start of a pattern.
983    29. Arrange for flags added by the "release type" setting in CMake to be shown
984        in the configuration summary.
987    Version 7.8 05-Sep-08
988    ---------------------
990    1.  Replaced UCP searching code with optimized version as implemented for Ad
991        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
992        stage table and inline lookup instead of a function, giving speed ups of 2
993        to 5 times on some simple patterns that I tested. Permission was given to
994        distribute the MultiStage2.py script that generates the tables (it's not in
995        the tarball, but is in the Subversion repository).
997    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
998        scripts.
1000    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1001        a group with a zero qualifier. The result of the study could be incorrect,
1002        or the function might crash, depending on the pattern.
1004    4.  Caseless matching was not working for non-ASCII characters in back
1005        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1006        It now works when Unicode Property Support is available.
1008    5.  In pcretest, an escape such as \x{de} in the data was always generating
1009        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1010        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1011        truncation.
1013    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1015    7.  Added two (int) casts to pcregrep when printing the difference of two
1016        pointers, in case they are 64-bit values.
1018    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1019        test 2 if it fails.
1021    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1022        and a #define of that name to empty if it is not externally set. This is to
1023        allow users of MSVC to set it if necessary.
1025    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1026        the convenience functions in the pcre_get.c source file.
1028    11. An option change at the start of a pattern that had top-level alternatives
1029        could cause overwriting and/or a crash. This command provoked a crash in
1030        some environments:
1032          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1034        This potential security problem was recorded as CVE-2008-2371.
1036    12. For a pattern where the match had to start at the beginning or immediately
1037        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1038        pcre_dfa_exec() could read past the end of the passed subject if there was
1039        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1040        pcretest so that it places the subject at the end of its malloc-ed buffer.
1042    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1043        exec() might read past the end of the data buffer in UTF-8 mode.
1045    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1046        the data contained the byte 0x85 as part of a UTF-8 character within its
1047        first line. This applied both to normal and DFA matching.
1049    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1050        /^[^d]*?$/8 failed to match "abc".
1052    16. Added a missing copyright notice to pcrecpp_internal.h.
1054    17. Make it more clear in the documentation that values returned from
1055        pcre_exec() in ovector are byte offsets, not character counts.
1057    18. Tidied a few places to stop certain compilers from issuing warnings.
1059    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1060        supplied by Stefan Weber. I made a further small update for 7.8 because
1061        there is a change of source arrangements: the pcre_searchfuncs.c module is
1062        replaced by pcre_ucd.c.
1065    Version 7.7 07-May-08
1066    ---------------------
1068    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1069        a string to a long long, pretend we don't even have a long long." This is
1070        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1072    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1073        pre-7.6 versions, which defined a global no_arg variable instead of putting
1074        it in the RE class. (See also #8 below.)
1076    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1077        Lopes.
1079    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1081        (1) The include/exclude patterns were being applied to the whole pathnames
1082            of files, instead of just to the final components.
1084        (2) If there was more than one level of directory, the subdirectories were
1085            skipped unless they satisfied the include/exclude conditions. This is
1086            inconsistent with GNU grep (and could even be seen as contrary to the
1087            pcregrep specification - which I improved to make it absolutely clear).
1088            The action now is always to scan all levels of directory, and just
1089            apply the include/exclude patterns to regular files.
1091    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1092        --exclude_dir in the tests to avoid scanning .svn directories.
1094    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1095        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1096        doesn't support NULs in patterns.
1098    7.  Added some missing "const"s to declarations of static tables in
1099        pcre_compile.c and pcre_dfa_exec.c.
1101    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1102        caused by fix #2  above. (Subsequently also a second patch to fix the
1103        first patch. And a third patch - this was a messy problem.)
1105    9.  Applied Craig's patch to remove the use of push_back().
1107    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1108        matching function regexec().
1110    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1111        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1112        references. PCRE supports relative numbers with this syntax (I don't think
1113        Oniguruma does).
1115    12. Previously, a group with a zero repeat such as (...){0} was completely
1116        omitted from the compiled regex. However, this means that if the group
1117        was called as a subroutine from elsewhere in the pattern, things went wrong
1118        (an internal error was given). Such groups are now left in the compiled
1119        pattern, with a new opcode that causes them to be skipped at execution
1120        time.
1122    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1123        to the way PCRE behaves:
1125        (a) A lone ] character is dis-allowed (Perl treats it as data).
1127        (b) A back reference to an unmatched subpattern matches an empty string
1128            (Perl fails the current match path).
1130        (c) A data ] in a character class must be notated as \] because if the
1131            first data character in a class is ], it defines an empty class. (In
1132            Perl it is not possible to have an empty class.) The empty class []
1133            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1134            The negative empty class [^] matches any one character, independently
1135            of the DOTALL setting.
1137    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1138        non-existent subpattern following a character class starting with ']' and
1139        containing () gave an internal compiling error instead of "reference to
1140        non-existent subpattern". Fortunately, when the pattern did exist, the
1141        compiled code was correct. (When scanning forwards to check for the
1142        existencd of the subpattern, it was treating the data ']' as terminating
1143        the class, so got the count wrong. When actually compiling, the reference
1144        was subsequently set up correctly.)
1146    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1147        it was being rejected as not supported by pcre_dfa_exec(), even though
1148        other assertions are supported. I have made pcre_dfa_exec() support
1149        (*FAIL).
1151    16. The implementation of 13c above involved the invention of a new opcode,
1152        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1153        cannot be changed at match time, I realized I could make a small
1154        improvement to matching performance by compiling OP_ALLANY instead of
1155        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1156        on the OP_ANY path.
1158    17. Compiling pcretest on Windows with readline support failed without the
1159        following two fixes: (1) Make the unistd.h include conditional on
1160        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1162    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1163        ncurses library to be included for pcretest when ReadLine support is
1164        requested, but also to allow for it to be overridden. This patch came from
1165        Daniel Bergström.
1167    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1168        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1169        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1170        spotting this.
1173    Version 7.6 28-Jan-08
1174    ---------------------
1176    1.  A character class containing a very large number of characters with
1177        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1178        overflow.
1180    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1181        HAVE_LONG_LONG is not defined.
1183    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1184        bring them up to date and include new features. This patch includes:
1186        - Fixed PH's badly added libz and libbz2 support.
1187        - Fixed a problem with static linking.
1188        - Added pcredemo. [But later removed - see 7 below.]
1189        - Fixed dftables problem and added an option.
1190        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1191            HAVE_LONG_LONG.
1192        - Added readline support for pcretest.
1193        - Added an listing of the option settings after cmake has run.
1195    4.  A user submitted a patch to Makefile that makes it easy to create
1196        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1197        Makefile.am that cause it to include this special target, without
1198        affecting anything else. Note that the same mingw target plus all
1199        the other distribution libraries and programs are now supported
1200        when configuring with CMake (see 6 below) instead of with
1201        Configure/Make.
1203    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1204        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1205        exported in the Windows port". It has not yet been confirmed that the patch
1206        solves the problem, but it does no harm.
1208    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1209        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1210        with CMake, and also correct the comment about stack recursion.
1212    7.  Remove the automatic building of pcredemo from the ./configure system and
1213        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1214        of a program that users should build themselves after PCRE is installed, so
1215        building it automatically is not really right. What is more, it gave
1216        trouble in some build environments.
1218    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1221    Version 7.5 10-Jan-08
1222    ---------------------
1224    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1225        values in parens when parsing an RE using the C++ wrapper."
1227    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1228        Characters greater than 255 were excluded from the class instead of being
1229        included.
1231    3.  The same bug as (2) above applied to negated POSIX classes such as
1232        [:^space:].
1234    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1235        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1236        I have changed it.
1238    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1239        first named subpattern) and a construct such as (?&a) would reference the
1240        first named subpattern whose name started with "a" (in other words, the
1241        length check was missing). Both these problems are fixed. "Subpattern name
1242        expected" is now given for (?&) (a zero-length name), and this patch also
1243        makes it give the same error for \k'' (previously it complained that that
1244        was a reference to a non-existent subpattern).
1246    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1247        this is right because (?- can be followed by option settings as well as by
1248        digits. I have, however, made the messages clearer.
1250    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1251        than the number used in the conditional) now cause a compile-time error.
1252        This is actually not compatible with Perl, which accepts such patterns, but
1253        treats the conditional as always being FALSE (as PCRE used to), but it
1254        seems to me that giving a diagnostic is better.
1256    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1257        and messages.
1259    9.  Fix two occurrences of "backslash" in comments that should have been
1260        "backspace".
1262    10. Remove two redundant lines of code that can never be obeyed (their function
1263        was moved elsewhere).
1265    11. The program that makes PCRE's Unicode character property table had a bug
1266        which caused it to generate incorrect table entries for sequences of
1267        characters that have the same character type, but are in different scripts.
1268        It amalgamated them into a single range, with the script of the first of
1269        them. In other words, some characters were in the wrong script. There were
1270        thirteen such cases, affecting characters in the following ranges:
1272          U+002b0 - U+002c1
1273          U+0060c - U+0060d
1274          U+0061e - U+00612
1275          U+0064b - U+0065e
1276          U+0074d - U+0076d
1277          U+01800 - U+01805
1278          U+01d00 - U+01d77
1279          U+01d9b - U+01dbf
1280          U+0200b - U+0200f
1281          U+030fc - U+030fe
1282          U+03260 - U+0327f
1283          U+0fb46 - U+0fbb1
1284          U+10450 - U+1049d
1286    12. The -o option (show only the matching part of a line) for pcregrep was not
1287        compatible with GNU grep in that, if there was more than one match in a
1288        line, it showed only the first of them. It now behaves in the same way as
1289        GNU grep.
1291    13. If the -o and -v options were combined for pcregrep, it printed a blank
1292        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1293        does the same. The return code can be used to tell if there were any
1294        non-matching lines.
1296    14. Added --file-offsets and --line-offsets to pcregrep.
1298    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1299        infinitely looping recursion. The bug was that positive lookaheads were not
1300        being skipped when checking for a possible empty match (negative lookaheads
1301        and both kinds of lookbehind were skipped).
1303    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1304        inclusion of <windows.h> to before rather than after the definition of
1305        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1307    17. Specifying a possessive quantifier with a specific limit for a Unicode
1308        character property caused pcre_compile() to compile bad code, which led at
1309        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1310        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1311        caused the error; without that there was no problem.
1313    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1315    19. Added --enable-pcretest-libreadline.
1317    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1318        RE::GlobalReplace(). As a result, the number of replacements returned was
1319        double what it should be. I removed one of the increments, but Craig sent a
1320        later patch that removed the other one (the right fix) and added unit tests
1321        that check the return values (which was not done before).
1323    21. Several CMake things:
1325        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1326            the names libpcre and libpcreposix, not just pcre and pcreposix.
1328        (2) The above change means that pcretest and pcregrep are now correctly
1329            linked with the newly-built libraries, not previously installed ones.
1333    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1334        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1335        UTF-8 newline character). The key issue is that the pattern starts .*;
1336        this means that the match must be either at the beginning, or after a
1337        newline. The bug was in the code for advancing after a failed match and
1338        checking that the new position followed a newline. It was not taking
1339        account of UTF-8 characters correctly.
1341    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1342        character classes. PCRE was not treating the sequence [:...:] as a
1343        character class unless the ... were all letters. Perl, however, seems to
1344        allow any characters between [: and :], though of course it rejects as
1345        unknown any "names" that contain non-letters, because all the known class
1346        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1347        for example, whereas PCRE did not - it did not recognize a POSIX character
1348        class. This seemed a bit dangerous, so the code has been changed to be
1349        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1350        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1351        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1352        Perl does, and where it didn't before.
1354    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1355        Windows environments %n is disabled by default.
1358    Version 7.4 21-Sep-07
1359    ---------------------
1361    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1362        means that a class such as [\s] counted as "explicit reference to CR or
1363        LF". That isn't really right - the whole point of the change was to try to
1364        help when there was an actual mention of one of the two characters. So now
1365        the change happens only if \r or \n (or a literal CR or LF) character is
1366        encountered.
1368    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1369        of both had grown to the point where there were only 3 bits left.
1370        Fortunately, there was spare space in the data structure, and so I have
1371        moved the internal flags into a new 16-bit field to free up more option
1372        bits.
1374    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1375        but did not set the internal JCHANGED flag - either of these is enough to
1376        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1377        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1378        start sets both bits.
1380    4.  Added options (at build time, compile time, exec time) to change \R from
1381        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1383    5.  doc/pcresyntax.html was missing from the distribution.
1385    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1386        compatibility, even though it is no longer used.
1388    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1389        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1390        windows.h file is present (where different names are used). [This was
1391        reversed later after testing - see 16 below.]
1393    8.  Changed all #include <config.h> to #include "config.h". There were also
1394        some further <pcre.h> cases that I changed to "pcre.h".
1396    9.  When pcregrep was used with the --colour option, it missed the line ending
1397        sequence off the lines that it output.
1399    10. It was pointed out to me that arrays of string pointers cause lots of
1400        relocations when a shared library is dynamically loaded. A technique of
1401        using a single long string with a table of offsets can drastically reduce
1402        these. I have refactored PCRE in four places to do this. The result is
1403        dramatic:
1405          Originally:                          290
1406          After changing UCP table:            187
1407          After changing error message table:   43
1408          After changing table of "verbs"       36
1409          After changing table of Posix names   22
1411        Thanks to the folks working on Gregex for glib for this insight.
1413    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1414        unicode-properties was also set.
1416    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1418    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1419        checked only for CRLF.
1421    14. Added casts to pcretest.c to avoid compiler warnings.
1423    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1425    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1426        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1427        entirely. This removes changes made in 7 above.
1429    17. The CMake files have been updated, and there is now more information about
1430        building with CMake in the NON-UNIX-USE document.
1433    Version 7.3 28-Aug-07
1434    ---------------------
1436     1. In the rejigging of the build system that eventually resulted in 7.1, the
1437        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1438        brackets there is not right, since it causes compilers to look for an
1439        installed pcre.h, not the version that is in the source that is being
1440        compiled (which of course may be different). I have changed it back to:
1442          #include "pcre.h"
1444        I have a vague recollection that the change was concerned with compiling in
1445        different directories, but in the new build system, that is taken care of
1446        by the VPATH setting the Makefile.
1448     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1449        when the subject happened to end in the byte 0x85 (e.g. if the last
1450        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1451        characters but of course it shouldn't be taken as a newline when it is part
1452        of another character. The bug was that, for an unlimited repeat of . in
1453        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1454        characters when looking for a newline.
1456     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1458     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1459        in debug output.
1461     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1462        long printing in the pcrecpp unittest when running under MinGW.
1464     6. ESC_K was left out of the EBCDIC table.
1466     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1467        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1468        limit also applies to "virtual nesting" when a pattern is recursive, and in
1469        this case 1000 isn't so big. I have been able to remove this limit at the
1470        expense of backing off one optimization in certain circumstances. Normally,
1471        when pcre_exec() would call its internal match() function recursively and
1472        immediately return the result unconditionally, it uses a "tail recursion"
1473        feature to save stack. However, when a subpattern that can match an empty
1474        string has an unlimited repetition quantifier, it no longer makes this
1475        optimization. That gives it a stack frame in which to save the data for
1476        checking that an empty string has been matched. Previously this was taken
1477        from the 1000-entry workspace that had been reserved. So now there is no
1478        explicit limit, but more stack is used.
1480     8. Applied Daniel's patches to solve problems with the import/export magic
1481        syntax that is required for Windows, and which was going wrong for the
1482        pcreposix and pcrecpp parts of the library. These were overlooked when this
1483        problem was solved for the main library.
1485     9. There were some crude static tests to avoid integer overflow when computing
1486        the size of patterns that contain repeated groups with explicit upper
1487        limits. As the maximum quantifier is 65535, the maximum group length was
1488        set at 30,000 so that the product of these two numbers did not overflow a
1489        32-bit integer. However, it turns out that people want to use groups that
1490        are longer than 30,000 bytes (though not repeat them that many times).
1491        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1492        made it possible to implement the integer overflow checks in a much more
1493        dynamic way, which I have now done. The artificial limitation on group
1494        length has been removed - we now have only the limit on the total length of
1495        the compiled pattern, which depends on the LINK_SIZE setting.
1497    10. Fixed a bug in the documentation for get/copy named substring when
1498        duplicate names are permitted. If none of the named substrings are set, the
1499        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1500        empty string.
1502    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1503        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1504        because the ] is interpreted as the first data character and the
1505        terminating ] is not found. PCRE has been made compatible with Perl in this
1506        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1507        cause memory overwriting.
1509    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1510        string has been matched (to stop an infinite loop). It was not recognizing
1511        a conditional subpattern that could match an empty string if that
1512        subpattern was within another subpattern. For example, it looped when
1513        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1514        condition was not nested. This bug has been fixed.
1516    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1517        past the start of the subject in the presence of bytes with the top bit
1518        set, for example "\x8aBCD".
1520    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1521        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1523    14. Optimized (?!) to (*FAIL).
1525    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1526        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1527        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1528        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1529        does: it's just the validity check that is more restrictive.
1531    16. Inserted checks for integer overflows during escape sequence (backslash)
1532        processing, and also fixed erroneous offset values for syntax errors during
1533        backslash processing.
1535    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1536        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1538    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1539        caused an overrun.
1541    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1542        something other than just ASCII characters) inside a group that had an
1543        unlimited repeat caused a loop at compile time (while checking to see
1544        whether the group could match an empty string).
1546    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1547        [\P{Any}] did so. (Error in the code for printing property names.)
1549    21. An orphan \E inside a character class could cause a crash.
1551    22. A repeated capturing bracket such as (A)? could cause a wild memory
1552        reference during compilation.
1554    23. There are several functions in pcre_compile() that scan along a compiled
1555        expression for various reasons (e.g. to see if it's fixed length for look
1556        behind). There were bugs in these functions when a repeated \p or \P was
1557        present in the pattern. These operators have additional parameters compared
1558        with \d, etc, and these were not being taken into account when moving along
1559        the compiled data. Specifically:
1561        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1562            length.
1564        (b) An item such as \pL+ within a repeated group could cause crashes or
1565            loops.
1567        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1568            "reference to non-existent subpattern" error.
1570        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1572    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1573        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1575    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1577    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1578        character were causing crashes (broken optimization).
1580    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1581        \p or \P) caused a compile-time loop.
1583    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1584        break. For example, the unstudied pattern [\r\n]A does not match the string
1585        "\r\nA" because change 7.0/46 below moves the current point on by two
1586        characters after failing to match at the start. However, the pattern \nA
1587        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1588        the same is true. There doesn't seem any very clean way out of this, but
1589        what I have chosen to do makes the common cases work: PCRE now takes note
1590        of whether there can be an explicit match for \r or \n anywhere in the
1591        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1592        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1593        pattern has explicit CR or LF references.
1595    29. Added (*CR) etc for changing newline setting at start of pattern.
1598    Version 7.2 19-Jun-07
1599    ---------------------
1601     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1602        which is apparently normally available under Windows.
1604     2. Re-jig the pcregrep tests with different newline settings in an attempt
1605        to make them independent of the local environment's newline setting.
1607     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1609     4. Some of the "internals" tests were previously cut out when the link size
1610        was not 2, because the output contained actual offsets. The recent new
1611        "Z" feature of pcretest means that these can be cut out, making the tests
1612        usable with all link sizes.
1614     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1615        stack recursion. This gives a massive performance boost under BSD, but just
1616        a small improvement under Linux. However, it saves one field in the frame
1617        in all cases.
1619     6. Added more features from the forthcoming Perl 5.10:
1621        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1622            recursion call. It refers to the nth most recently opened parentheses.
1624        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1625            to be opened parentheses.
1627        (c) Conditions that refer to capturing parentheses can be specified
1628            relatively, for example, (?(-2)... or (?(+3)...
1630        (d) \K resets the start of the current match so that everything before
1631            is not part of it.
1633        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1635        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1636            reference syntax.
1638        (g) (?| introduces a group in which the numbering of parentheses in each
1639            alternative starts with the same number.
1641        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1643     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1646     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1647        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1648        for detecting groups that can match an empty string.
1650     9. A pattern with a very large number of alternatives (more than several
1651        hundred) was running out of internal workspace during the pre-compile
1652        phase, where pcre_compile() figures out how much memory will be needed. A
1653        bit of new cunning has reduced the workspace needed for groups with
1654        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1655        workspace instead of running out of the 4096 that are available.
1657    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1659    11. Applied patch from Google to remove an optimization that didn't quite work.
1660        The report of the bug said:
1662          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1663          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1664          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1666    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1667        it matched the wrong number of bytes.
1670    Version 7.1 24-Apr-07
1671    ---------------------
1673     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1674        that is more "standard", making use of automake and other Autotools. There
1675        is some re-arrangement of the files and adjustment of comments consequent
1676        on this.
1678     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1679        for recursive directory scanning broke on some systems because the files
1680        are not scanned in any specific order and on different systems the order
1681        was different. A call to "sort" has been inserted into RunGrepTest for the
1682        approprate test as a short-term fix. In the longer term there may be an
1683        alternative.
1685     3. I had an email from Eric Raymond about problems translating some of PCRE's
1686        man pages to HTML (despite the fact that I distribute HTML pages, some
1687        people do their own conversions for various reasons). The problems
1688        concerned the use of low-level troff macros .br and .in. I have therefore
1689        removed all such uses from the man pages (some were redundant, some could
1690        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1691        HTML has been updated to handle .nf/.fi and to complain if it encounters
1692        .br or .in.
1694     4. Updated comments in configure.ac that get placed in config.h.in and also
1695        arranged for config.h to be included in the distribution, with the name
1696        config.h.generic, for the benefit of those who have to compile without
1697        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1699     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1700        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1701        makevp.bat for the current PCRE, using the additional files
1702        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1704     6. A Windows user reported a minor discrepancy with test 2, which turned out
1705        to be caused by a trailing space on an input line that had got lost in his
1706        copy. The trailing space was an accident, so I've just removed it.
1708     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1709        that is needed.
1711     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1712        as "const" (a) because they are and (b) because it helps the PHP
1713        maintainers who have recently made a script to detect big data structures
1714        in the php code that should be moved to the .rodata section. I remembered
1715        to update Builducptable as well, so it won't revert if ucptable.h is ever
1716        re-created.
1718     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1719        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1720        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1721        support is not required. This saves 1.5-2K of code, which is important in
1722        some applications.
1724        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1725        so as not to refer to the tables, even though these functions will never be
1726        called when UTF-8 support is disabled. Otherwise there are problems with a
1727        shared library.
1729    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1731        (a) It was defining its arguments as char * instead of void *.
1733        (b) It was assuming that all moves were upwards in memory; this was true
1734            a long time ago when I wrote it, but is no longer the case.
1736        The emulated memove() is provided for those environments that have neither
1737        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1738        is clearly not the case, as these two bugs were recently reported.
1740    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1741        and Detrail to create the HTML documentation, the .txt form of the man
1742        pages, and it removes trailing spaces from listed files. It also creates
1743        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1744        case, it wraps all the #defines with #ifndefs. This script should be run
1745        before "make dist".
1747    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1748        with Unicode property support.
1750        (a) For a maximizing quantifier, if the two different cases of the
1751            character were of different lengths in their UTF-8 codings (there are
1752            some cases like this - I found 11), and the matching function had to
1753            back up over a mixture of the two cases, it incorrectly assumed they
1754            were both the same length.
1756        (b) When PCRE was configured to use the heap rather than the stack for
1757            recursion during matching, it was not correctly preserving the data for
1758            the other case of a UTF-8 character when checking ahead for a match
1759            while processing a minimizing repeat. If the check also involved
1760            matching a wide character, but failed, corruption could cause an
1761            erroneous result when trying to check for a repeat of the original
1762            character.
1764    13. Some tidying changes to the testing mechanism:
1766        (a) The RunTest script now detects the internal link size and whether there
1767            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1768            values substituted by "configure". (The RunGrepTest script already did
1769            this for UTF-8.) The configure.ac script no longer substitutes the
1770            relevant variables.
1772        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1773            with length and offset values. This means that the output is different
1774            for different internal link sizes. Test 2 is skipped for link sizes
1775            other than 2 because of this, bypassing the problem. Unfortunately,
1776            there was also a test in test 3 (the locale tests) that used /B and
1777            failed for link sizes other than 2. Rather than cut the whole test out,
1778            I have added a new /Z option to pcretest that replaces the length and
1779            offset values with spaces. This is now used to make test 3 independent
1780            of link size. (Test 2 will be tidied up later.)
1782    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1783        segmentation fault instead of returning the appropriate error message.
1785    15. In multiline mode when the newline sequence was set to "any", the pattern
1786        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1787        This doesn't seem right; it now treats the CRLF combination as the line
1788        ending, and so does not match in that case. It's only a pattern such as ^$
1789        that would hit this one: something like ^ABC$ would have failed after \r
1790        and then tried again after \r\n.
1792    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1793        in an attempt to make files that differ only in their line terminators
1794        compare equal. This works on Linux.
1796    17. Under certain error circumstances pcregrep might try to free random memory
1797        as it exited. This is now fixed, thanks to valgrind.
1799    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1800        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1801        was because its rules for how to advance for /g after matching an empty
1802        string at the end of a line did not allow for this case. They now check for
1803        it specially.
1805    20. pcretest is supposed to handle patterns and data of any length, by
1806        extending its buffers when necessary. It was getting this wrong when the
1807        buffer for a data line had to be extended.
1809    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1810        CRLF as a newline sequence.
1812    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1813        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1814        I have nevertheless tidied it up.
1816    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1818    24. Added a man page for pcre-config.
1821    Version 7.0 19-Dec-06
1822    ---------------------
1824     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1825        moving to gcc 4.1.1.
1827     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1828        sys/time.h, which is documented as needed for this function. It doesn't
1829        seem to matter on Linux, but it showed up on some releases of OS X.
1831     3. It seems that there are systems where bytes whose values are greater than
1832        127 match isprint() in the "C" locale. The "C" locale should be the
1833        default when a C program starts up. In most systems, only ASCII printing
1834        characters match isprint(). This difference caused the output from pcretest
1835        to vary, making some of the tests fail. I have changed pcretest so that:
1837        (a) When it is outputting text in the compiled version of a pattern, bytes
1838            other than 32-126 are always shown as hex escapes.
1840        (b) When it is outputting text that is a matched part of a subject string,
1841            it does the same, unless a different locale has been set for the match
1842            (using the /L modifier). In this case, it uses isprint() to decide.
1844     4. Fixed a major bug that caused incorrect computation of the amount of memory
1845        required for a compiled pattern when options that changed within the
1846        pattern affected the logic of the preliminary scan that determines the
1847        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1848        that the computed length was too small. The symptoms of this bug were
1849        either the PCRE error "internal error: code overflow" from pcre_compile(),
1850        or a glibc crash with a message such as "pcretest: free(): invalid next
1851        size (fast)". Examples of patterns that provoked this bug (shown in
1852        pcretest format) are:
1854          /(?-x: )/x
1855          /(?x)(?-x: \s*#\s*)/
1856          /((?i)[\x{c0}])/8
1857          /(?i:[\x{c0}])/8
1859        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1860        is now done differently.
1862     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1863        wrapper classes; (b) implement a new function in the C++ scanner that is
1864        more efficient than the old way of doing things because it avoids levels of
1865        recursion in the regex matching; (c) add a paragraph to the documentation
1866        for the FullMatch() function.
1868     6. The escape sequence \n was being treated as whatever was defined as
1869        "newline". Not only was this contrary to the documentation, which states
1870        that \n is character 10 (hex 0A), but it also went horribly wrong when
1871        "newline" was defined as CRLF. This has been fixed.
1873     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1874        was being set to -1 for the "end of line" case (supposedly a value that no
1875        character can have). Though this value is never used (the check for end of
1876        line is "zero bytes in current character"), it caused compiler complaints.
1877        I've changed it to 0xffffffff.
1879     8. In pcre_version.c, the version string was being built by a sequence of
1880        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1881        string (as it is for production releases) called a macro with an empty
1882        argument. The C standard says the result of this is undefined. The gcc
1883        compiler treats it as an empty string (which was what was wanted) but it is
1884        reported that Visual C gives an error. The source has been hacked around to
1885        avoid this problem.
1887     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1888        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1889        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1890        of them did).
1892    10. Originally, pcretest opened its input and output without "b"; then I was
1893        told that "b" was needed in some environments, so it was added for release
1894        5.0 to both the input and output. (It makes no difference on Unix-like
1895        systems.) Later I was told that it is wrong for the input on Windows. I've
1896        now abstracted the modes into two macros, to make it easier to fiddle with
1897        them, and removed "b" from the input mode under Windows.
1899    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1901    12. Added -help and --help to pcretest as an official way of being reminded
1902        of the options.
1904    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1905        and pcrecpp.cc because they annoy compilers at high warning levels.
1907    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1909    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1910        scripts are not C programs :-) and which was not noticed because it works
1911        on Linux.
1913    16. pcretest is supposed to handle any length of pattern and data line (as one
1914        line or as a continued sequence of lines) by extending its input buffer if
1915        necessary. This feature was broken for very long pattern lines, leading to
1916        a string of junk being passed to pcre_compile() if the pattern was longer
1917        than about 50K.
1919    17. I have done a major re-factoring of the way pcre_compile() computes the
1920        amount of memory needed for a compiled pattern. Previously, there was code
1921        that made a preliminary scan of the pattern in order to do this. That was
1922        OK when PCRE was new, but as the facilities have expanded, it has become
1923        harder and harder to keep it in step with the real compile phase, and there
1924        have been a number of bugs (see for example, 4 above). I have now found a
1925        cunning way of running the real compile function in a "fake" mode that
1926        enables it to compute how much memory it would need, while actually only
1927        ever using a few hundred bytes of working memory and without too many
1928        tests of the mode. This should make future maintenance and development
1929        easier. A side effect of this work is that the limit of 200 on the nesting
1930        depth of parentheses has been removed (though this was never a serious
1931        limitation, I suspect). However, there is a downside: pcre_compile() now
1932        runs more slowly than before (30% or more, depending on the pattern). I
1933        hope this isn't a big issue. There is no effect on runtime performance.
1935    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1936        newline (only possible for the last line of a file) and it was a
1937        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1939    19. Added additional timing features to pcretest. (1) The -tm option now times
1940        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1941        separate command line item, by a number that specifies the number of
1942        repeats to use when timing. The default is 50000; this gives better
1943        precision, but takes uncomfortably long for very large patterns.
1945    20. Extended pcre_study() to be more clever in cases where a branch of a
1946        subpattern has no definite first character. For example, (a*|b*)[cd] would
1947        previously give no result from pcre_study(). Now it recognizes that the
1948        first character must be a, b, c, or d.
1950    21. There was an incorrect error "recursive call could loop indefinitely" if
1951        a subpattern (or the entire pattern) that was being tested for matching an
1952        empty string contained only one non-empty item after a nested subpattern.
1953        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1954        incorrectly, because the \d was being skipped in the check.
1956    22. The pcretest program now has a new pattern option /B and a command line
1957        option -b, which is equivalent to adding /B to every pattern. This causes
1958        it to show the compiled bytecode, without the additional information that
1959        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1960        is the same as /B/I).
1962    23. A new optimization is now able automatically to treat some sequences such
1963        as a*b as a*+b. More specifically, if something simple (such as a character
1964        or a simple class like \d) has an unlimited quantifier, and is followed by
1965        something that cannot possibly match the quantified thing, the quantifier
1966        is automatically "possessified".
1968    24. A recursive reference to a subpattern whose number was greater than 39
1969        went wrong under certain circumstances in UTF-8 mode. This bug could also
1970        have affected the operation of pcre_study().
1972    25. Realized that a little bit of performance could be had by replacing
1973        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1975    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1977    27. Possessive quantifiers such as a++ were previously implemented by turning
1978        them into atomic groups such as ($>a+). Now they have their own opcodes,
1979        which improves performance. This includes the automatically created ones
1980        from 23 above.
1982    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1983        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1984        the first matched character to be a colon. This applied both to named and
1985        numbered groups.
1987    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1989    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1990        building PCRE on Windows easier, so I have included it in the distribution.
1992    31. There is now a check in pcretest against a ridiculously large number being
1993        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1994        loop, the loop is abandoned.
1996    32. Forward references to subpatterns in conditions such as (?(2)...) where
1997        subpattern 2 is defined later cause pcre_compile() to search forwards in
1998        the pattern for the relevant set of parentheses. This search went wrong
1999        when there were unescaped parentheses in a character class, parentheses
2000        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2002    33. "Subroutine" calls and backreferences were previously restricted to
2003        referencing subpatterns earlier in the regex. This restriction has now
2004        been removed.
2006    34. Added a number of extra features that are going to be in Perl 5.10. On the
2007        whole, these are just syntactic alternatives for features that PCRE had
2008        previously implemented using the Python syntax or my own invention. The
2009        other formats are all retained for compatibility.
2011        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2012            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2013            also .NET compatible.
2015        (b) A recursion or subroutine call to a named group can now be defined as
2016            (?&name) as well as (?P>name).
2018        (c) A backreference to a named group can now be defined as \k<name> or
2019            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2020            5.10, are also .NET compatible.
2022        (d) A conditional reference to a named group can now use the syntax
2023            (?(<name>) or (?('name') as well as (?(name).
2025        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2026            groups (named and numbered) that are never evaluated inline, but can be
2027            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2028            is always false. There may be only one alternative in such a group.
2030        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2031            as the simple (?(R). The condition is true only if the most recent
2032            recursion is that of the given number or name. It does not search out
2033            through the entire recursion stack.
2035        (g) The escape \gN or \g{N} has been added, where N is a positive or
2036            negative number, specifying an absolute or relative reference.
2038    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2039        some "unreachable code" warnings.
2041    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2042        things, this adds five new scripts.
2044    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2045        There were also incompatibilities regarding the handling of \Q..\E inside
2046        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2047        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2049    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2050        matches an empty string, and forcibly breaks the loop. There were bugs in
2051        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2052        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2053        separate and independent bugs (that affected different cases) have been
2054        fixed.
2056    39. Refactored the code to abolish the use of different opcodes for small
2057        capturing bracket numbers. This is a tidy that I avoided doing when I
2058        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2059        The new approach is not only tidier, it makes it possible to reduce the
2060        memory needed to fix the previous bug (38).
2062    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2063        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2064        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2065        mode.
2067    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2068        report.
2070    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2071        copy construction and assignment in the C++ wrapper.
2073    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2074        couple of bugs that could have given wrong results in the "--newline=crlf"
2075        case.
2077    44. Added a number of casts and did some reorganization of signed/unsigned int
2078        variables following suggestions from Dair Grant. Also renamed the variable
2079        "this" as "item" because it is a C++ keyword.
2081    45. Arranged for dftables to add
2083          #include "pcre_internal.h"
2085        to pcre_chartables.c because without it, gcc 4.x may remove the array
2086        definition from the final binary if PCRE is built into a static library and
2087        dead code stripping is activated.
2089    46. For an unanchored pattern, if a match attempt fails at the start of a
2090        newline sequence, and the newline setting is CRLF or ANY, and the next two
2091        characters are CRLF, advance by two characters instead of one.
2094    Version 6.7 04-Jul-06
2095    ---------------------
2097     1. In order to handle tests when input lines are enormously long, pcretest has
2098        been re-factored so that it automatically extends its buffers when
2099        necessary. The code is crude, but this _is_ just a test program. The
2100        default size has been increased from 32K to 50K.
2102     2. The code in pcre_study() was using the value of the re argument before
2103        testing it for NULL. (Of course, in any sensible call of the function, it
2104        won't be NULL.)
2106     3. The memmove() emulation function in pcre_internal.h, which is used on
2107        systems that lack both memmove() and bcopy() - that is, hardly ever -
2108        was missing a "static" storage class specifier.
2110     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2111        containing an extended class (one that cannot be represented by a bitmap
2112        because it contains high-valued characters or Unicode property items, e.g.
2113        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2114        pattern, but PCRE should not loop if you do not (it no longer does).
2115        [Detail: two cases were found: (a) a repeated subpattern containing an
2116        extended class; (b) a recursive reference to a subpattern that followed a
2117        previous extended class. It wasn't skipping over the extended class
2118        correctly when UTF-8 mode was not set.]
2120     5. A negated single-character class was not being recognized as fixed-length
2121        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2122        compile error "lookbehind assertion is not fixed length".
2124     6. The RunPerlTest auxiliary script was showing an unexpected difference
2125        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2126        write a Perl script that can interpret lines of an input file either as
2127        byte characters or as UTF-8, which is what "perltest" was being required to
2128        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2129        can't do is switch easily at run time between having the "use utf8;" pragma
2130        or not. In the end, I fudged it by using the RunPerlTest script to insert
2131        "use utf8;" explicitly for the UTF-8 tests.
2133     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2134        the end of the subject string, contrary to the documentation and to what
2135        Perl does. This was true of both matching functions. Now it matches only at
2136        the start of the subject and immediately after *internal* newlines.
2138     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2139        a pointer to an int instead of a pointer to an unsigned long int. This
2140        caused problems on 64-bit systems.
2142     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2143        instance of the 'standard' template library not being so standard".
2145    10. There was no check on the number of named subpatterns nor the maximum
2146        length of a subpattern name. The product of these values is used to compute
2147        the size of the memory block for a compiled pattern. By supplying a very
2148        long subpattern name and a large number of named subpatterns, the size
2149        computation could be caused to overflow. This is now prevented by limiting
2150        the length of names to 32 characters, and the number of named subpatterns
2151        to 10,000.
2153    11. Subpatterns that are repeated with specific counts have to be replicated in
2154        the compiled pattern. The size of memory for this was computed from the
2155        length of the subpattern and the repeat count. The latter is limited to
2156        65535, but there was no limit on the former, meaning that integer overflow
2157        could in principle occur. The compiled length of a repeated subpattern is
2158        now limited to 30,000 bytes in order to prevent this.
2160    12. Added the optional facility to have named substrings with the same name.
2162    13. Added the ability to use a named substring as a condition, using the
2163        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2164        are numbers (not recommended). Forward references are permitted.
2166    14. Added forward references in named backreferences (if you see what I mean).
2168    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2169        pattern could run off the end of the subject. For example, the pattern
2170        "(?s)(.{1,5})"8 did this with the subject "ab".
2172    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2173        PCRE_CASELESS was set when matching characters that were quantified with ?
2174        or *.
2176    17. A character class other than a single negated character that had a minimum
2177        but no maximum quantifier - for example [ab]{6,} - was not handled
2178        correctly by pce_dfa_exec(). It would match only one character.
2180    18. A valid (though odd) pattern that looked like a POSIX character
2181        class but used an invalid character after [ (for example [[,abc,]]) caused
2182        pcre_compile() to give the error "Failed: internal error: code overflow" or
2183        in some cases to crash with a glibc free() error. This could even happen if
2184        the pattern terminated after [[ but there just happened to be a sequence of
2185        letters, a binary zero, and a closing ] in the memory that followed.
2187    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2188        over the years. Originally (before any Unicode support), just the bottom 8
2189        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2190        output from "man perlunicode" includes this:
2192          The regular expression compiler produces polymorphic opcodes.  That
2193          is, the pattern adapts to the data and automatically switches to
2194          the Unicode character scheme when presented with Unicode data--or
2195          instead uses a traditional byte scheme when presented with byte
2196          data.
2198        Sadly, a wide octal escape does not cause a switch, and in a string with
2199        no other multibyte characters, these octal escapes are treated as before.
2200        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2201        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2202        Unicode string.
2204        I have not perpetrated such confusion in PCRE. Up till now, it took just
2205        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2206        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2207        translate to the appropriate multibyte character.
2209    29. Applied some refactoring to reduce the number of warnings from Microsoft
2210        and Borland compilers. This has included removing the fudge introduced
2211        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2212        a warning about an unused variable.
2214    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2215        characters since release 4.0, because Perl (from release 5.004) does not.
2216        [Or at least, is documented not to: some releases seem to be in conflict
2217        with the documentation.] However, when a pattern was studied with
2218        pcre_study() and all its branches started with \s, PCRE still included VT
2219        as a possible starting character. Of course, this did no harm; it just
2220        caused an unnecessary match attempt.
2222    22. Removed a now-redundant internal flag bit that recorded the fact that case
2223        dependency changed within the pattern. This was once needed for "required
2224        byte" processing, but is no longer used. This recovers a now-scarce options
2225        bit. Also moved the least significant internal flag bit to the most-
2226        significant bit of the word, which was not previously used (hangover from
2227        the days when it was an int rather than a uint) to free up another bit for
2228        the future.
2230    23. Added support for CRLF line endings as well as CR and LF. As well as the
2231        default being selectable at build time, it can now be changed at runtime
2232        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2233        specify that it is scanning data with non-default line endings.
2235    24. Changed the definition of CXXLINK to make it agree with the definition of
2236        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2238    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2239        recursions. This makes a big different to stack usage for some patterns.
2241    26. If a subpattern containing a named recursion or subroutine reference such
2242        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2243        the space required for the compiled pattern went wrong and gave too small a
2244        value. Depending on the environment, this could lead to "Failed: internal
2245        error: code overflow at offset 49" or "glibc detected double free or
2246        corruption" errors.
2248    27. Applied patches from Google (a) to support the new newline modes and (b) to
2249        advance over multibyte UTF-8 characters in GlobalReplace.
2251    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2252        difference for some implementation of PCRE in some Windows version.
2254    29. Added some extra testing facilities to pcretest:
2256        \q<number>   in a data line sets the "match limit" value
2257        \Q<number>   in a data line sets the "match recursion limt" value
2258        -S <number>  sets the stack size, where <number> is in megabytes
2260        The -S option isn't available for Windows.
2263    Version 6.6 06-Feb-06
2264    ---------------------
2266     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2267        in pcreposix.h. I have copied the definition from pcre.h.
2269     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2270        because pcre.h is no longer a built file.
2272     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2273        not normally included in the compiled code.
2276    Version 6.5 01-Feb-06
2277    ---------------------
2279     1. When using the partial match feature with pcre_dfa_exec(), it was not
2280        anchoring the second and subsequent partial matches at the new starting
2281        point. This could lead to incorrect results. For example, with the pattern
2282        /1234/, partially matching against "123" and then "a4" gave a match.
2284     2. Changes to pcregrep:
2286        (a) All non-match returns from pcre_exec() were being treated as failures
2287            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2288            error message is output. Some extra information is given for the
2289            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2290            probably the only errors that are likely to be caused by users (by
2291            specifying a regex that has nested indefinite repeats, for instance).
2292            If there are more than 20 of these errors, pcregrep is abandoned.
2294        (b) A binary zero was treated as data while matching, but terminated the
2295            output line if it was written out. This has been fixed: binary zeroes
2296            are now no different to any other data bytes.
2298        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2299            used to set a locale for matching. The --locale=xxxx long option has
2300            been added (no short equivalent) to specify a locale explicitly on the
2301            pcregrep command, overriding the environment variables.
2303        (d) When -B was used with -n, some line numbers in the output were one less
2304            than they should have been.
2306        (e) Added the -o (--only-matching) option.
2308        (f) If -A or -C was used with -c (count only), some lines of context were
2309            accidentally printed for the final match.
2311        (g) Added the -H (--with-filename) option.
2313        (h) The combination of options -rh failed to suppress file names for files
2314            that were found from directory arguments.
2316        (i) Added the -D (--devices) and -d (--directories) options.
2318        (j) Added the -F (--fixed-strings) option.
2320        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2322        (l) Added the --colo(u)r option.
2324        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2325            is not present by default.
2327     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2328        items such as (?R) or (?1), when the recursion could match a number of
2329        alternatives. If it matched one of the alternatives, but subsequently,
2330        outside the recursion, there was a failure, the code tried to back up into
2331        the recursion. However, because of the way PCRE is implemented, this is not
2332        possible, and the result was an incorrect result from the match.
2334        In order to prevent this happening, the specification of recursion has
2335        been changed so that all such subpatterns are automatically treated as
2336        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2338     4. I had overlooked the fact that, in some locales, there are characters for
2339        which isalpha() is true but neither isupper() nor islower() are true. In
2340        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2341        and ordfeminine) are like this. This affected the treatment of \w and \W
2342        when they appeared in character classes, but not when they appeared outside
2343        a character class. The bit map for "word" characters is now created
2344        separately from the results of isalnum() instead of just taking it from the
2345        upper, lower, and digit maps. (Plus the underscore character, of course.)
2347     5. The above bug also affected the handling of POSIX character classes such as
2348        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2349        permanent tables. Instead, the bit maps for such a class were previously
2350        created as the appropriate unions of the upper, lower, and digit bitmaps.
2351        Now they are created by subtraction from the [[:word:]] class, which has
2352        its own bitmap.
2354     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2355        It is created by subtracting the vertical space characters (\x09, \x0a,
2356        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2357        subtraction was done in the overall bitmap for a character class, meaning
2358        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2359        be recognized. This bug has been fixed.
2361     7. Patches from the folks at Google:
2363          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2364          real life, but is still worth protecting against".
2366          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2367          regular expressions".
2369          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2370          have it.
2372          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2373          "configure" and the latter not, in order to fix a problem somebody had
2374          with compiling the Arg class on HP-UX.
2376          (e) Improve the error-handling of the C++ wrapper a little bit.
2378          (f) New tests for checking recursion limiting.
2380     8. The pcre_memmove() function, which is used only if the environment does not
2381        have a standard memmove() function (and is therefore rarely compiled),
2382        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2383        returning a result (though PCRE never actually uses the result).
2385     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2386        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2387        returned instead of calling malloc() with an overflowing number that would
2388        most likely cause subsequent chaos.
2390    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2392    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2393        with this option is matched, the nmatch and pmatch options of regexec() are
2394        ignored.
2396    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2397        provided in case anyone wants to the the POSIX interface with UTF-8
2398        strings.
2400    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2401        C++ linking (needed for some HP-UX environments).
2403    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2404        (unused parameter) and in the pcre_printint() function (omitted "default"
2405        switch label when the default is to do nothing).
2407    15. Added some code to make it possible, when PCRE is compiled as a C++
2408        library, to replace subject pointers for pcre_exec() with a smart pointer
2409        class, thus making it possible to process discontinuous strings.
2411    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2412        much the same function. They were added by different people who were trying
2413        to make PCRE easy to compile on non-Unix systems. It has been suggested
2414        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2415        for compiling on Windows systems. I have therefore replaced it with
2416        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2417        defaults to "extern" for C or "extern C" for C++, which works fine on
2418        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2419        SCOPE with something explicit in config.h. In addition:
2421        (a) pcreposix.h still had just "extern" instead of either of these macros;
2422            I have replaced it with PCRE_DATA_SCOPE.
2424        (b) Functions such as _pcre_xclass(), which are internal to the library,
2425            but external in the C sense, all had PCRE_EXPORT in their definitions.
2426            This is apparently wrong for the Windows case, so I have removed it.
2427            (It makes no difference on Unix-like systems.)
2429    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2430        of recursive calls to match(). This is different to MATCH_LIMIT because
2431        that limits the total number of calls to match(), not all of which increase
2432        the depth of recursion. Limiting the recursion depth limits the amount of
2433        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2434        when PCRE is compiled, and changed at run time. A patch from Google adds
2435        this functionality to the C++ interface.
2437    18. Changes to the handling of Unicode character properties:
2439        (a) Updated the table to Unicode 4.1.0.
2441        (b) Recognize characters that are not in the table as "Cn" (undefined).
2443        (c) I revised the way the table is implemented to a much improved format
2444            which includes recognition of ranges. It now supports the ranges that
2445            are defined in UnicodeData.txt, and it also amalgamates other
2446            characters into ranges. This has reduced the number of entries in the
2447            table from around 16,000 to around 3,000, thus reducing its size
2448            considerably. I realized I did not need to use a tree structure after
2449            all - a binary chop search is just as efficient. Having reduced the
2450            number of entries, I extended their size from 6 bytes to 8 bytes to
2451            allow for more data.
2453        (d) Added support for Unicode script names via properties such as \p{Han}.
2455    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2456        matching that character.
2458    20. When matching a repeated Unicode property with a minimum greater than zero,
2459        (for example \pL{2,}), PCRE could look past the end of the subject if it
2460        reached it while seeking the minimum number of characters. This could
2461        happen only if some of the characters were more than one byte long, because
2462        there is a check for at least the minimum number of bytes.
2464    21. Refactored the implementation of \p and \P so as to be more general, to
2465        allow for more different types of property in future. This has changed the
2466        compiled form incompatibly. Anybody with saved compiled patterns that use
2467        \p or \P will have to recompile them.
2469    22. Added "Any" and "L&" to the supported property types.
2471    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2472        but give a compile time error if the value is greater than 0xff.
2474    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2475        accidentally not being installed or uninstalled.
2477    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2478        made were to insert the current release number. This seemed silly, because
2479        it made things harder for people building PCRE on systems that don't run
2480        "configure". I have turned pcre.h into a distributed file, no longer built
2481        by "configure", with the version identification directly included. There is
2482        no longer a pcre.h.in file.
2484        However, this change necessitated a change to the pcre-config script as
2485        well. It is built from pcre-config.in, and one of the substitutions was the
2486        release number. I have updated configure.ac so that ./configure now finds
2487        the release number by grepping pcre.h.
2489    26. Added the ability to run the tests under valgrind.
2492    Version 6.4 05-Sep-05
2493    ---------------------
2495     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2496        "--" to be printed when multiple files were scanned, even when none of the
2497        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2498        consider it to be a bug, and have restored the previous behaviour.
2500     2. A couple of code tidies to get rid of compiler warnings.
2502     3. The pcretest program used to cheat by referring to symbols in the library
2503        whose names begin with _pcre_. These are internal symbols that are not
2504        really supposed to be visible externally, and in some environments it is
2505        possible to suppress them. The cheating is now confined to including
2506        certain files from the library's source, which is a bit cleaner.
2508     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2509        file's purpose clearer.
2511     5. Reorganized pcre_ucp_findchar().
2514    Version 6.3 15-Aug-05
2515    ---------------------
2517     1. The file libpcre.pc.in did not have general read permission in the tarball.
2519     2. There were some problems when building without C++ support:
2521        (a) If C++ support was not built, "make install" and "make test" still
2522            tried to test it.
2524        (b) There were problems when the value of CXX was explicitly set. Some
2525            changes have been made to try to fix these, and ...
2527        (c) --disable-cpp can now be used to explicitly disable C++ support.
2529        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2530            backslash in a target when C++ was disabled. This confuses some
2531            versions of "make", apparently. Using an intermediate variable solves
2532            this. (Same for CPP_LOBJ.)
2534     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2535        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2536        necessary on certain architectures.
2538     4. Added a setting of -export-symbols-regex to the link command to remove
2539        those symbols that are exported in the C sense, but actually are local
2540        within the library, and not documented. Their names all begin with
2541        "_pcre_". This is not a perfect job, because (a) we have to except some
2542        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2543        available (and never for static libraries). I have made a note to try to
2544        find a way round (a) in the future.
2547    Version 6.2 01-Aug-05
2548    ---------------------
2550     1. There was no test for integer overflow of quantifier values. A construction
2551        such as {1111111111111111} would give undefined results. What is worse, if
2552        a minimum quantifier for a parenthesized subpattern overflowed and became
2553        negative, the calculation of the memory size went wrong. This could have
2554        led to memory overwriting.
2556     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2558     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2559        operating environments where this matters.
2561     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2562        PCRE options from within the C++ wrapper.
2564     5. Named capturing subpatterns were not being correctly counted when a pattern
2565        was compiled. This caused two problems: (a) If there were more than 100
2566        such subpatterns, the calculation of the memory needed for the whole
2567        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2568        back references of the form \12, where the number was greater than 9, were
2569        not recognized as back references, even though there were sufficient
2570        previous subpatterns.
2572     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2573        versions of gcc, e.g. 2.95.4.
2576    Version 6.1 21-Jun-05
2577    ---------------------
2579     1. There was one reference to the variable "posix" in pcretest.c that was not
2580        surrounded by "#if !defined NOPOSIX".
2582     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2583        the cross-check on the old pcre_info() function, for the benefit of the
2584        cut-down version of PCRE that is currently imported into Exim.
2586     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2587        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2588        patterns that start (?i) but I don't think that matters. The use of (?i) is
2589        just an example; this all applies to the other options as well.
2591     4. Since libtool seems to echo the compile commands it is issuing, the output
2592        from "make" can be reduced a bit by putting "@" in front of each libtool
2593        compile command.
2595     5. Patch from the folks at Google for configure.in to be a bit more thorough
2596        in checking for a suitable C++ installation before trying to compile the
2597        C++ stuff. This should fix a reported problem when a compiler was present,
2598        but no suitable headers.
2600     6. The man pages all had just "PCRE" as their title. I have changed them to
2601        be the relevant file name. I have also arranged that these names are
2602        retained in the file doc/pcre.txt, which is a concatenation in text format
2603        of all the man pages except the little individual ones for each function.
2605     7. The NON-UNIX-USE file had not been updated for the different set of source
2606        files that come with release 6. I also added a few comments about the C++
2607        wrapper.
2610    Version 6.0 07-Jun-05
2611    ---------------------
2613     1. Some minor internal re-organization to help with my DFA experiments.
2615     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2616        didn't matter for the library itself when fully configured, but did matter
2617        when compiling without UCP support, or within Exim, where the ucp files are
2618        not imported.
2620     3. Refactoring of the library code to split up the various functions into
2621        different source modules. The addition of the new DFA matching code (see
2622        below) to a single monolithic source would have made it really too
2623        unwieldy, quite apart from causing all the code to be include in a
2624        statically linked application, when only some functions are used. This is
2625        relevant even without the DFA addition now that patterns can be compiled in
2626        one application and matched in another.
2628        The downside of splitting up is that there have to be some external
2629        functions and data tables that are used internally in different modules of
2630        the library but which are not part of the API. These have all had their
2631        names changed to start with "_pcre_" so that they are unlikely to clash
2632        with other external names.
2634     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2635        a different (DFA) algorithm. Although it is slower than the original
2636        function, it does have some advantages for certain types of matching
2637        problem.
2639     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2640        including restarting after a partial match.
2642     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2643        defined when compiling for Windows was sent to me. I have put it into the
2644        code, though I have no means of testing or verifying it.
2646     7. Added the pcre_refcount() auxiliary function.
2648     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2649        match before or at the first newline in the subject string. In pcretest,
2650        the /f option on a pattern can be used to set this.
2652     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2653        would behave wrongly. This has been present in PCRE since release 4.0.
2655    10. A number of changes to the pcregrep command:
2657        (a) Refactored how -x works; insert ^(...)$ instead of setting
2658            PCRE_ANCHORED and checking the length, in preparation for adding
2659            something similar for -w.
2661        (b) Added the -w (match as a word) option.
2663        (c) Refactored the way lines are read and buffered so as to have more
2664            than one at a time available.
2666        (d) Implemented a pcregrep test script.
2668        (e) Added the -M (multiline match) option. This allows patterns to match
2669            over several lines of the subject. The buffering ensures that at least
2670            8K, or the rest of the document (whichever is the shorter) is available
2671            for matching (and similarly the previous 8K for lookbehind assertions).
2673        (f) Changed the --help output so that it now says
2675              -w, --word-regex(p)
2677            instead of two lines, one with "regex" and the other with "regexp"
2678            because that confused at least one person since the short forms are the
2679            same. (This required a bit of code, as the output is generated
2680            automatically from a table. It wasn't just a text change.)
2682        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2683            option but starts with a hyphen. Could be a pattern or a path name
2684            starting with a hyphen, for instance.
2686        (h) "-" can be given as a file name to represent stdin.
2688        (i) When file names are being printed, "(standard input)" is used for
2689            the standard input, for compatibility with GNU grep. Previously
2690            "<stdin>" was used.
2692        (j) The option --label=xxx can be used to supply a name to be used for
2693            stdin when file names are being printed. There is no short form.
2695        (k) Re-factored the options decoding logic because we are going to add
2696            two more options that take data. Such options can now be given in four
2697            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2699        (l) Added the -A, -B, and -C options for requesting that lines of context
2700            around matches be printed.
2702        (m) Added the -L option to print the names of files that do not contain
2703            any matching lines, that is, the complement of -l.
2705        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2706            continue to scan other files.
2708        (o) The -s option was incorrectly implemented. For compatibility with other
2709            greps, it now suppresses the error message for a non-existent or non-
2710            accessible file (but not the return code). There is a new option called
2711            -q that suppresses the output of matching lines, which was what -s was
2712            previously doing.
2714        (p) Added --include and --exclude options to specify files for inclusion
2715            and exclusion when recursing.
2717    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2718        Hopefully, it now does.
2720    12. Missing cast in pcre_study().
2722    13. Added an "uninstall" target to the makefile.
2724    14. Replaced "extern" in the function prototypes in Makefile.in with
2725        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2726        world, but is set differently for Windows.
2728    15. Added a second compiling function called pcre_compile2(). The only
2729        difference is that it has an extra argument, which is a pointer to an
2730        integer error code. When there is a compile-time failure, this is set
2731        non-zero, in addition to the error test pointer being set to point to an
2732        error message. The new argument may be NULL if no error number is required
2733        (but then you may as well call pcre_compile(), which is now just a
2734        wrapper). This facility is provided because some applications need a
2735        numeric error indication, but it has also enabled me to tidy up the way
2736        compile-time errors are handled in the POSIX wrapper.
2738    16. Added VPATH=.libs to the makefile; this should help when building with one
2739        prefix path and installing with another. (Or so I'm told by someone who
2740        knows more about this stuff than I do.)
2742    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2743        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2744        match everything, including newlines. This is not POSIX-compatible, but
2745        somebody wanted the feature. From pcretest it can be activated by using
2746        both the P and the s flags.
2748    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2750    19. libpcre.pc was being incorrectly installed as executable.
2752    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2753        it now also looks for '\r' so that it will work unmodified on Windows.
2755    21. Added Google's contributed C++ wrapper to the distribution.
2757    22. Added some untidy missing memory free() calls in pcretest, to keep
2758        Electric Fence happy when testing.
2762    Version 5.0 13-Sep-04
2763    ---------------------
2765     1. Internal change: literal characters are no longer packed up into items
2766        containing multiple characters in a single byte-string. Each character
2767        is now matched using a separate opcode. However, there may be more than one
2768        byte in the character in UTF-8 mode.
2770     2. The pcre_callout_block structure has two new fields: pattern_position and
2771        next_item_length. These contain the offset in the pattern to the next match
2772        item, and its length, respectively.
2774     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2775        insertion of callouts before each pattern item. Added the /C option to
2776        pcretest to make use of this.
2778     4. On the advice of a Windows user, the lines
2780          #if defined(_WIN32) || defined(WIN32)
2781          _setmode( _fileno( stdout ), 0x8000 );
2782          #endif  /* defined(_WIN32) || defined(WIN32) */
2784        have been added to the source of pcretest. This apparently does useful
2785        magic in relation to line terminators.
2787     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2788        for the benefit of those environments where the "b" makes a difference.
2790     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2791        to know about it. I have put a hack into configure.in that adds in code
2792        to set GCC=yes if CC=icc. This seems to end up at a point in the
2793        generated configure script that is early enough to affect the setting of
2794        compiler options, which is what is needed, but I have no means of testing
2795        whether it really works. (The user who reported this had patched the
2796        generated configure script, which of course I cannot do.)
2798        LATER: After change 22 below (new libtool files), the configure script
2799        seems to know about icc (and also ecc). Therefore, I have commented out
2800        this hack in configure.in.
2802     7. Added support for pkg-config (2 patches were sent in).
2804     8. Negated POSIX character classes that used a combination of internal tables
2805        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2806        [[:^ascii]]. Typically, they would match almost any characters. The other
2807        POSIX classes were not broken in this way.
2809     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2810        to find the match, as PCRE was deluded into thinking that the match had to
2811        start at the start point or following a newline. The same bug applied to
2812        patterns with negative forward assertions or any backward assertions
2813        preceding ".*" at the start, unless the pattern required a fixed first
2814        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2816    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2817        starting at the last subject character, bytes beyond the end of the subject
2818        string were read.
2820    11. Renamed the variable "class" as "classbits" to make life easier for C++
2821        users. (Previously there was a macro definition, but it apparently wasn't
2822        enough.)
2824    12. Added the new field "tables" to the extra data so that tables can be passed
2825        in at exec time, or the internal tables can be re-selected. This allows
2826        a compiled regex to be saved and re-used at a later time by a different
2827        program that might have everything at different addresses.
2829    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2830        -R library as well as a -L library.
2832    14. The debugging options of pcretest (-d on the command line or D on a
2833        pattern) showed incorrect output for anything following an extended class
2834        that contained multibyte characters and which was followed by a quantifier.
2836    15. Added optional support for general category Unicode character properties
2837        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2838        support. It adds about 90K to the size of the library. The meanings of the
2839        inbuilt class escapes such as \d and \s have NOT been changed.
2841    16. Updated pcredemo.c to include calls to free() to release the memory for the
2842        compiled pattern.
2844    17. The generated file chartables.c was being created in the source directory
2845        instead of in the building directory. This caused the build to fail if the
2846        source directory was different from the building directory, and was
2847        read-only.
2849    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2850        file. No doubt somebody will tell me if they don't make sense... Also added
2851        Dan Mooney's comments about building on OpenVMS.
2853    19. Added support for partial matching via the PCRE_PARTIAL option for
2854        pcre_exec() and the \P data escape in pcretest.
2856    20. Extended pcretest with 3 new pattern features:
2858        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2859              write the compiled pattern to the file whose name is "rest-of-line".
2860              This is a straight binary dump of the data, with the saved pointer to
2861              the character tables forced to be NULL. The study data, if any, is
2862              written too. After writing, pcretest reads a new pattern.
2864        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2865              compiled pattern from the given file. There must not be any
2866              occurrences of "<" in the file name (pretty unlikely); if there are,
2867              pcretest will instead treat the initial "<" as a pattern delimiter.
2868              After reading in the pattern, pcretest goes on to read data lines as
2869              usual.
2871        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2872              and 16-bit fields in a compiled pattern, to simulate a pattern that
2873              was compiled on a host of opposite endianness.
2875    21. The pcre-exec() function can now cope with patterns that were compiled on
2876        hosts of opposite endianness, with this restriction:
2878          As for any compiled expression that is saved and used later, the tables
2879          pointer field cannot be preserved; the extra_data field in the arguments
2880          to pcre_exec() should be used to pass in a tables address if a value
2881          other than the default internal tables were used at compile time.
2883    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2884        now diagnosed as an error. Previously, most of the time, a negative number
2885        would have been treated as zero, but if in addition "ovector" was passed as
2886        NULL, a crash could occur.
2888    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2889        new versions from the libtool 1.5 distribution (the last one is a copy of
2890        a file called libtool.m4). This seems to have fixed the need to patch
2891        "configure" to support Darwin 1.3 (which I used to do). However, I still
2892        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2893        workstation).
2895    24. Changed the PCRE licence to be the more standard "BSD" licence.
2898  Version 4.5 01-Dec-03  Version 4.5 01-Dec-03
2899  ---------------------  ---------------------

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