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revision 73 by nigel, Sat Feb 24 21:40:30 2007 UTC revision 645 by ph10, Sun Jul 31 17:02:18 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
14    
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
23    
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
28    
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
34    
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
38    
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
46    
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
55    
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
59    
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
62    
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
68    
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
72    
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
77    
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
86    
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
90    
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
95    
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
102    
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
106    
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
109    
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
113    
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
116    
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
125    
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
129    
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
136    
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
140    
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
147    
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
151    
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
154    
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
157    
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
161    
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
165    
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
168    
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
175    
176    33. Previously, PCRE did not allow quantification of assertions. However, Perl
177        does, and because of capturing effects, quantifying parenthesized
178        assertions may at times be useful. Quantifiers are now allowed for
179        parenthesized assertions.
180    
181    34. A minor code tidy in pcre_compile() when checking options for \R usage.
182    
183    35. \g was being checked for fancy things in a character class, when it should
184        just be a literal "g".
185    
186    36. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
187        appearance of a nested POSIX class supersedes an apparent external class.
188        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
189        unescaped square brackets may also appear as part of class names. For
190        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
191        more like Perl.
192    
193    37. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
194        was because it thought it was \N{name}, which is not supported).
195    
196    38. Add minix to OS list not supporting the -S option in pcretest.
197    
198    39. PCRE tries to detect cases of infinite recursion at compile time, but it
199        cannot analyze patterns in sufficient detail to catch mutual recursions
200        such as ((?1))((?2)). There is now a runtime test that gives an error if a
201        subgroup is called recursively as a subpattern for a second time at the
202        same position in the subject string. In previous releases this might have
203        been caught by the recursion limit, or it might have run out of stack.
204    
205    40. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
206        happen only once. PCRE was, however incorrectly giving a compile time error
207        "recursive call could loop indefinitely" because it cannot analyze the
208        pattern in sufficient detail. The compile time test no longer happens when
209        PCRE is compiling a conditional subpattern, but actual runaway loops are
210        now caught at runtime (see 39 above).
211    
212    41. It seems that Perl allows any characters other than a closing parenthesis
213        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
214        has been changed to be the same.
215    
216    42. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
217        as not to get warnings when autogen.sh is called. Also changed
218        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
219    
220    43. To help people who use pcregrep to scan files containing exceedingly long
221        lines, the following changes have been made:
222    
223        (a) The default value of the buffer size parameter has been increased from
224            8K to 20K. (A buffer three times this size is actually used.)
225    
226        (b) The default can be changed by ./configure --with-pcregrep-bufsiz when
227            PCRE is built.
228    
229        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
230            to be set at run time.
231    
232        (d) Numerical values in pcregrep options can be followed by K or M, for
233            example --buffer-size=50K.
234    
235        (e) If a line being scanned overflows pcregrep's buffer, an error is now
236            given and the return code is set to 2.
237    
238    44. Add a pointer to the latest mark to the callout data block.
239    
240    
241    Version 8.12 15-Jan-2011
242    ------------------------
243    
244    1.  Fixed some typos in the markup of the man pages, and wrote a script that
245        checks for such things as part of the documentation building process.
246    
247    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
248        --match-limit and --recursion-limit options (added for 8.11). In
249        particular, this made one of the standard tests fail. (The integer value
250        went into the wrong half of a long int.)
251    
252    3.  If the --colour option was given to pcregrep with -v (invert match), it
253        did strange things, either producing crazy output, or crashing. It should,
254        of course, ignore a request for colour when reporting lines that do not
255        match.
256    
257    4.  Another pcregrep bug caused similar problems if --colour was specified with
258        -M (multiline) and the pattern match finished with a line ending.
259    
260    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
261        matched in multiline mode, the following line was shown as part of the
262        match. This seems wrong, so I have changed it.
263    
264    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
265        the check for further matches in the same line (so they could be coloured)
266        to overrun the end of the current line. If another match was found, it was
267        incorrectly shown (and then shown again when found in the next line).
268    
269    7.  If pcregrep was compiled under Windows, there was a reference to the
270        function pcregrep_exit() before it was defined. I am assuming this was
271        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
272        reported by a user. I've moved the definition above the reference.
273    
274    
275    Version 8.11 10-Dec-2010
276    ------------------------
277    
278    1.  (*THEN) was not working properly if there were untried alternatives prior
279        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
280        backtracked to try for "b" instead of moving to the next alternative branch
281        at the same level (in this case, to look for "c"). The Perl documentation
282        is clear that when (*THEN) is backtracked onto, it goes to the "next
283        alternative in the innermost enclosing group".
284    
285    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
286        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
287        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
288        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
289        (*THEN).
290    
291    3.  If \s appeared in a character class, it removed the VT character from
292        the class, even if it had been included by some previous item, for example
293        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
294        of \s, but is part of the POSIX "space" class.)
295    
296    4.  A partial match never returns an empty string (because you can always
297        match an empty string at the end of the subject); however the checking for
298        an empty string was starting at the "start of match" point. This has been
299        changed to the "earliest inspected character" point, because the returned
300        data for a partial match starts at this character. This means that, for
301        example, /(?<=abc)def/ gives a partial match for the subject "abc"
302        (previously it gave "no match").
303    
304    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
305        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
306        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
307        has an implication that the given string is incomplete (because a partial
308        match is preferred over a full match). For this reason, these items now
309        give a partial match in this situation. [Aside: previously, the one case
310        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
311        match rather than a full match, which was wrong by the old rules, but is
312        now correct.]
313    
314    6.  There was a bug in the handling of #-introduced comments, recognized when
315        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
316        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
317        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
318        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
319        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
320        places in pcre_compile().
321    
322    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
323        comments when looking ahead for named forward references to subpatterns,
324        the only newline sequence it recognized was NL. It now handles newlines
325        according to the set newline convention.
326    
327    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
328        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
329        cater for a lack of strerror(). These oversights have been fixed.
330    
331    9.  Added --match-limit and --recursion-limit to pcregrep.
332    
333    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
334    
335    11. When the -o option was used, pcregrep was setting a return code of 1, even
336        when matches were found, and --line-buffered was not being honoured.
337    
338    12. Added an optional parentheses number to the -o and --only-matching options
339        of pcregrep.
340    
341    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
342        can match an empty string. The code to do it in pcretest and pcredemo
343        needed fixing:
344    
345        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
346            only one byte after an empty string match just before CRLF (this case
347            just got forgotten; "any" and "anycrlf" were OK).
348    
349        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
350            mode when an empty string match preceded an ASCII character followed by
351            a non-ASCII character. (The code for advancing by one character rather
352            than one byte was nonsense.)
353    
354        (c) The pcredemo.c sample program did not have any code at all to handle
355            the cases when CRLF is a valid newline sequence.
356    
357    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
358        as a starting offset was within the subject string. There is now a new
359        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
360        negative or greater than the length of the string. In order to test this,
361        pcretest is extended to allow the setting of negative starting offsets.
362    
363    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
364        starting offset points to the beginning of a UTF-8 character was
365        unnecessarily clumsy. I tidied it up.
366    
367    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
368        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
369    
370    17. Nobody had reported that the --include_dir option, which was added in
371        release 7.7 should have been called --include-dir (hyphen, not underscore)
372        for compatibility with GNU grep. I have changed it to --include-dir, but
373        left --include_dir as an undocumented synonym, and the same for
374        --exclude-dir, though that is not available in GNU grep, at least as of
375        release 2.5.4.
376    
377    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
378        characters from a string of bytes) have been redefined so as not to use
379        loops, in order to improve performance in some environments. At the same
380        time, I abstracted some of the common code into auxiliary macros to save
381        repetition (this should not affect the compiled code).
382    
383    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
384        compile-time error is now given if \c is not followed by an ASCII
385        character, that is, a byte less than 128. (In EBCDIC mode, the code is
386        different, and any byte value is allowed.)
387    
388    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
389        START_OPTIMIZE option, which is now allowed at compile time - but just
390        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
391        to pcregrep and other applications that have no direct access to PCRE
392        options. The new /Y option in pcretest sets this option when calling
393        pcre_compile().
394    
395    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
396        back references. Groups containing recursive back references were forced to
397        be atomic by that change, but in the case of named groups, the amount of
398        memory required was incorrectly computed, leading to "Failed: internal
399        error: code overflow". This has been fixed.
400    
401    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
402        pcretest.c, to avoid build problems in some Borland environments.
403    
404    
405    Version 8.10 25-Jun-2010
406    ------------------------
407    
408    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
409        THEN.
410    
411    2.  (*ACCEPT) was not working when inside an atomic group.
412    
413    3.  Inside a character class, \B is treated as a literal by default, but
414        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
415        causes the error). The code is unchanged, but I tidied the documentation.
416    
417    4.  Inside a character class, PCRE always treated \R and \X as literals,
418        whereas Perl faults them if its -w option is set. I have changed PCRE so
419        that it faults them when PCRE_EXTRA is set.
420    
421    5.  Added support for \N, which always matches any character other than
422        newline. (It is the same as "." when PCRE_DOTALL is not set.)
423    
424    6.  When compiling pcregrep with newer versions of gcc which may have
425        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
426        declared with attribute warn_unused_result" were given. Just casting the
427        result to (void) does not stop the warnings; a more elaborate fudge is
428        needed. I've used a macro to implement this.
429    
430    7.  Minor change to pcretest.c to avoid a compiler warning.
431    
432    8.  Added four artifical Unicode properties to help with an option to make
433        \s etc use properties (see next item). The new properties are: Xan
434        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
435    
436    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
437        use Unicode properties. (*UCP) at the start of a pattern can be used to set
438        this option. Modified pcretest to add /W to test this facility. Added
439        REG_UCP to make it available via the POSIX interface.
440    
441    10. Added --line-buffered to pcregrep.
442    
443    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
444        studied, and the match started with a letter with a code point greater than
445        127 whose first byte was different to the first byte of the other case of
446        the letter, the other case of this starting letter was not recognized
447        (#976).
448    
449    12. If a pattern that was studied started with a repeated Unicode property
450        test, for example, \p{Nd}+, there was the theoretical possibility of
451        setting up an incorrect bitmap of starting bytes, but fortunately it could
452        not have actually happened in practice until change 8 above was made (it
453        added property types that matched character-matching opcodes).
454    
455    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
456        possible starting bytes for non-anchored patterns.
457    
458    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
459        \R, and also a number of cases that involve Unicode properties, both
460        explicit and implicit when PCRE_UCP is set.
461    
462    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
463        input, it could crash or give wrong results if characters with values
464        greater than 0xc0 were present in the subject string. (Detail: it assumed
465        UTF-8 input when processing these items.)
466    
467    16. Added a lot of (int) casts to avoid compiler warnings in systems where
468        size_t is 64-bit (#991).
469    
470    17. Added a check for running out of memory when PCRE is compiled with
471        --disable-stack-for-recursion (#990).
472    
473    18. If the last data line in a file for pcretest does not have a newline on
474        the end, a newline was missing in the output.
475    
476    19. The default pcre_chartables.c file recognizes only ASCII characters (values
477        less than 128) in its various bitmaps. However, there is a facility for
478        generating tables according to the current locale when PCRE is compiled. It
479        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
480        characters, are recognized by isspace() and therefore were getting set in
481        these tables, and indeed these tables seem to approximate to ISO 8859. This
482        caused a problem in UTF-8 mode when pcre_study() was used to create a list
483        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
484        which of course cannot start UTF-8 characters. I have changed the code so
485        that only real ASCII characters (less than 128) and the correct starting
486        bytes for UTF-8 encodings are set for characters greater than 127 when in
487        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
488        altogether.)
489    
490    20. Added the /T option to pcretest so as to be able to run tests with non-
491        standard character tables, thus making it possible to include the tests
492        used for 19 above in the standard set of tests.
493    
494    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
495        reference to a subpattern the other side of a comment that contains an
496        opening parenthesis caused either an internal compiling error, or a
497        reference to the wrong subpattern.
498    
499    
500    Version 8.02 19-Mar-2010
501    ------------------------
502    
503    1.  The Unicode data tables have been updated to Unicode 5.2.0.
504    
505    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
506        configured.
507    
508    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
509        original author of that file, following a query about its status.
510    
511    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
512        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
513    
514    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
515        quantifier applied to a forward-referencing subroutine call, could compile
516        incorrect code or give the error "internal error: previously-checked
517        referenced subpattern not found".
518    
519    6.  Both MS Visual Studio and Symbian OS have problems with initializing
520        variables to point to external functions. For these systems, therefore,
521        pcre_malloc etc. are now initialized to local functions that call the
522        relevant global functions.
523    
524    7.  There were two entries missing in the vectors called coptable and poptable
525        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
526        I've fixed the data, and added a kludgy way of testing at compile time that
527        the lengths are correct (equal to the number of opcodes).
528    
529    8.  Following on from 7, I added a similar kludge to check the length of the
530        eint vector in pcreposix.c.
531    
532    9.  Error texts for pcre_compile() are held as one long string to avoid too
533        much relocation at load time. To find a text, the string is searched,
534        counting zeros. There was no check for running off the end of the string,
535        which could happen if a new error number was added without updating the
536        string.
537    
538    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
539    
540    11. \K was not working if it appeared in an atomic group or in a group that
541        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
542        \K is "not well defined" if used in an assertion. PCRE now accepts it if
543        the assertion is positive, but not if it is negative.
544    
545    12. Change 11 fortuitously reduced the size of the stack frame used in the
546        "match()" function of pcre_exec.c by one pointer. Forthcoming
547        implementation of support for (*MARK) will need an extra pointer on the
548        stack; I have reserved it now, so that the stack frame size does not
549        decrease.
550    
551    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
552        item in branch that calls a recursion is a subroutine call - as in the
553        second branch in the above example - was incorrectly given the compile-
554        time error "recursive call could loop indefinitely" because pcre_compile()
555        was not correctly checking the subroutine for matching a non-empty string.
556    
557    14. The checks for overrunning compiling workspace could trigger after an
558        overrun had occurred. This is a "should never occur" error, but it can be
559        triggered by pathological patterns such as hundreds of nested parentheses.
560        The checks now trigger 100 bytes before the end of the workspace.
561    
562    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
563    
564    
565    Version 8.01 19-Jan-2010
566    ------------------------
567    
568    1.  If a pattern contained a conditional subpattern with only one branch (in
569        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
570        computed the wrong minimum data length (which is of course zero for such
571        subpatterns). This could cause incorrect "no match" results.
572    
573    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
574        the pattern is reset in the first branch, pcre_compile() failed with
575        "internal error: code overflow at offset...". This happened only when
576        the reset was to the original external option setting. (An optimization
577        abstracts leading options settings into an external setting, which was the
578        cause of this.)
579    
580    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
581        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
582        assertion pattern did not match (meaning that the assertion was true), it
583        was incorrectly treated as false if the SKIP had been reached during the
584        matching. This also applied to assertions used as conditions.
585    
586    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
587        assertion subpattern, including such a pattern used as a condition,
588        unpredictable results occurred, instead of the error return
589        PCRE_ERROR_DFA_UITEM.
590    
591    5.  The C++ GlobalReplace function was not working like Perl for the special
592        situation when an empty string is matched. It now does the fancy magic
593        stuff that is necessary.
594    
595    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
596        removed. (These were left over from very, very early versions of PCRE.)
597    
598    7.  Some cosmetic changes to the code to make life easier when compiling it
599        as part of something else:
600    
601        (a) Change DEBUG to PCRE_DEBUG.
602    
603        (b) In pcre_compile(), rename the member of the "branch_chain" structure
604            called "current" as "current_branch", to prevent a collision with the
605            Linux macro when compiled as a kernel module.
606    
607        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
608            prevent a collision with the Linux macro when compiled as a kernel
609            module.
610    
611    8.  In pcre_compile() there are some checks for integer overflows that used to
612        cast potentially large values to (double). This has been changed to that
613        when building, a check for int64_t is made, and if it is found, it is used
614        instead, thus avoiding the use of floating point arithmetic. (There is no
615        other use of FP in PCRE.) If int64_t is not found, the fallback is to
616        double.
617    
618    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
619        2005 (difference between two addresses compared to an unsigned value).
620    
621    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
622        custom one, because of the following reported problem in Windows:
623    
624          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
625              under Win32.
626          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
627              therefore missing the function definition.
628          - The compiler thus generates a "C" signature for the test function.
629          - The linker fails to find the "C" function.
630          - PCRE fails to configure if asked to do so against libbz2.
631    
632    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
633        messages were output:
634    
635          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
636          rerunning libtoolize, to keep the correct libtool macros in-tree.
637          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
638    
639        I have done both of these things.
640    
641    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
642        most of the time, it *can* run out if it is given a pattern that contains a
643        runaway infinite recursion. I updated the discussion in the pcrestack man
644        page.
645    
646    13. Now that we have gone to the x.xx style of version numbers, the minor
647        version may start with zero. Using 08 or 09 is a bad idea because users
648        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
649        interpreted as invalid octal numbers. I've updated the previous comment in
650        configure.ac, and also added a check that gives an error if 08 or 09 are
651        used.
652    
653    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
654        causing partial matching to fail when the end of the subject matched \W
655        in a UTF-8 pattern where \W was quantified with a minimum of 3.
656    
657    15. There were some discrepancies between the declarations in pcre_internal.h
658        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
659        their definitions. The declarations used "const uschar *" and the
660        definitions used USPTR. Even though USPTR is normally defined as "const
661        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
662        reported that: "This difference in casting confuses some C++ compilers, for
663        example, SunCC recognizes above declarations as different functions and
664        generates broken code for hbpcre." I have changed the declarations to use
665        USPTR.
666    
667    16. GNU libtool is named differently on some systems. The autogen.sh script now
668        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
669        (FreeBSD).
670    
671    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
672        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
673        comment: "Figure out how to create a longlong from a string: strtoll and
674        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
675        instance, but it only takes 2 args instead of 3!"
676    
677    18. A subtle bug concerned with back references has been fixed by a change of
678        specification, with a corresponding code fix. A pattern such as
679        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
680        refers, was giving matches when it shouldn't. For example, xa=xaaa would
681        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
682        same bug. Such groups have to be quantified to be useful, or contained
683        inside another quantified group. (If there's no repetition, the reference
684        can never match.) The problem arises because, having left the group and
685        moved on to the rest of the pattern, a later failure that backtracks into
686        the group uses the captured value from the final iteration of the group
687        rather than the correct earlier one. I have fixed this in PCRE by forcing
688        any group that contains a reference to itself to be an atomic group; that
689        is, there cannot be any backtracking into it once it has completed. This is
690        similar to recursive and subroutine calls.
691    
692    
693    Version 8.00 19-Oct-09
694    ----------------------
695    
696    1.  The table for translating pcre_compile() error codes into POSIX error codes
697        was out-of-date, and there was no check on the pcre_compile() error code
698        being within the table. This could lead to an OK return being given in
699        error.
700    
701    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
702        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
703        in a Windows environment.
704    
705    3.  The pcregrep --count option prints the count for each file even when it is
706        zero, as does GNU grep. However, pcregrep was also printing all files when
707        --files-with-matches was added. Now, when both options are given, it prints
708        counts only for those files that have at least one match. (GNU grep just
709        prints the file name in this circumstance, but including the count seems
710        more useful - otherwise, why use --count?) Also ensured that the
711        combination -clh just lists non-zero counts, with no names.
712    
713    4.  The long form of the pcregrep -F option was incorrectly implemented as
714        --fixed_strings instead of --fixed-strings. This is an incompatible change,
715        but it seems right to fix it, and I didn't think it was worth preserving
716        the old behaviour.
717    
718    5.  The command line items --regex=pattern and --regexp=pattern were not
719        recognized by pcregrep, which required --regex pattern or --regexp pattern
720        (with a space rather than an '='). The man page documented the '=' forms,
721        which are compatible with GNU grep; these now work.
722    
723    6.  No libpcreposix.pc file was created for pkg-config; there was just
724        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
725    
726    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
727        when UCP support is not needed, by modifying the Python script that
728        generates it from Unicode data files. This should not matter if the module
729        is correctly used as a library, but I received one complaint about 50K of
730        unwanted data. My guess is that the person linked everything into his
731        program rather than using a library. Anyway, it does no harm.
732    
733    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
734        was a minimum greater than 1 for a wide character in a possessive
735        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
736        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
737        character. Chaos in the form of incorrect output or a compiling loop could
738        result.
739    
740    9.  The restrictions on what a pattern can contain when partial matching is
741        requested for pcre_exec() have been removed. All patterns can now be
742        partially matched by this function. In addition, if there are at least two
743        slots in the offset vector, the offset of the earliest inspected character
744        for the match and the offset of the end of the subject are set in them when
745        PCRE_ERROR_PARTIAL is returned.
746    
747    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
748        synonymous with PCRE_PARTIAL, for backwards compatibility, and
749        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
750        and may be more useful for multi-segment matching.
751    
752    11. Partial matching with pcre_exec() is now more intuitive. A partial match
753        used to be given if ever the end of the subject was reached; now it is
754        given only if matching could not proceed because another character was
755        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
756        string "Z", which now yields "no match" instead of "partial match". In the
757        case of pcre_dfa_exec(), "no match" is given if every matching path for the
758        final character ended with (*FAIL).
759    
760    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
761        if the pattern had a "must contain" character that was already found in the
762        earlier partial match, unless partial matching was again requested. For
763        example, with the pattern /dog.(body)?/, the "must contain" character is
764        "g". If the first part-match was for the string "dog", restarting with
765        "sbody" failed. This bug has been fixed.
766    
767    13. The string returned by pcre_dfa_exec() after a partial match has been
768        changed so that it starts at the first inspected character rather than the
769        first character of the match. This makes a difference only if the pattern
770        starts with a lookbehind assertion or \b or \B (\K is not supported by
771        pcre_dfa_exec()). It's an incompatible change, but it makes the two
772        matching functions compatible, and I think it's the right thing to do.
773    
774    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
775        so that the demonstration program is easily available in environments where
776        PCRE has not been installed from source.
777    
778    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
779        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
780        library.
781    
782    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
783        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
784        is not the first non-POSIX option to be added. Clearly some people find
785        these options useful.
786    
787    17. If a caller to the POSIX matching function regexec() passes a non-zero
788        value for nmatch with a NULL value for pmatch, the value of
789        nmatch is forced to zero.
790    
791    18. RunGrepTest did not have a test for the availability of the -u option of
792        the diff command, as RunTest does. It now checks in the same way as
793        RunTest, and also checks for the -b option.
794    
795    19. If an odd number of negated classes containing just a single character
796        interposed, within parentheses, between a forward reference to a named
797        subpattern and the definition of the subpattern, compilation crashed with
798        an internal error, complaining that it could not find the referenced
799        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
800        [The bug was that it was starting one character too far in when skipping
801        over the character class, thus treating the ] as data rather than
802        terminating the class. This meant it could skip too much.]
803    
804    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
805        /g option in pcretest when the pattern contains \K, which makes it possible
806        to have an empty string match not at the start, even when the pattern is
807        anchored. Updated pcretest and pcredemo to use this option.
808    
809    21. If the maximum number of capturing subpatterns in a recursion was greater
810        than the maximum at the outer level, the higher number was returned, but
811        with unset values at the outer level. The correct (outer level) value is
812        now given.
813    
814    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
815        PCRE did not set those parentheses (unlike Perl). I have now found a way to
816        make it do so. The string so far is captured, making this feature
817        compatible with Perl.
818    
819    23. The tests have been re-organized, adding tests 11 and 12, to make it
820        possible to check the Perl 5.10 features against Perl 5.10.
821    
822    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
823        pattern matches a fixed length string. PCRE did not allow this; now it
824        does. Neither allows recursion.
825    
826    25. I finally figured out how to implement a request to provide the minimum
827        length of subject string that was needed in order to match a given pattern.
828        (It was back references and recursion that I had previously got hung up
829        on.) This code has now been added to pcre_study(); it finds a lower bound
830        to the length of subject needed. It is not necessarily the greatest lower
831        bound, but using it to avoid searching strings that are too short does give
832        some useful speed-ups. The value is available to calling programs via
833        pcre_fullinfo().
834    
835    26. While implementing 25, I discovered to my embarrassment that pcretest had
836        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
837        study optimizations had never been tested with that matching function.
838        Oops. What is worse, even when it was passed study data, there was a bug in
839        pcre_dfa_exec() that meant it never actually used it. Double oops. There
840        were also very few tests of studied patterns with pcre_dfa_exec().
841    
842    27. If (?| is used to create subpatterns with duplicate numbers, they are now
843        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
844        on the other side of the coin, they are no longer allowed to have different
845        names, because these cannot be distinguished in PCRE, and this has caused
846        confusion. (This is a difference from Perl.)
847    
848    28. When duplicate subpattern names are present (necessarily with different
849        numbers, as required by 27 above), and a test is made by name in a
850        conditional pattern, either for a subpattern having been matched, or for
851        recursion in such a pattern, all the associated numbered subpatterns are
852        tested, and the overall condition is true if the condition is true for any
853        one of them. This is the way Perl works, and is also more like the way
854        testing by number works.
855    
856    
857    Version 7.9 11-Apr-09
858    ---------------------
859    
860    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
861        (pcretest), all targets were linked against these libraries. This included
862        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
863        libraries. This caused unwanted dependencies to be created. This problem
864        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
865        pcretest is linked with readline.
866    
867    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
868        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
869        moved outside it again, because FALSE and TRUE are already defined in AIX,
870        but BOOL is not.
871    
872    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
873        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
874    
875    4.  The pcregrep documentation said spaces were inserted as well as colons (or
876        hyphens) following file names and line numbers when outputting matching
877        lines. This is not true; no spaces are inserted. I have also clarified the
878        wording for the --colour (or --color) option.
879    
880    5.  In pcregrep, when --colour was used with -o, the list of matching strings
881        was not coloured; this is different to GNU grep, so I have changed it to be
882        the same.
883    
884    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
885        each matching line was coloured. Now it goes on to look for further matches
886        of any of the test patterns, which is the same behaviour as GNU grep.
887    
888    7.  A pattern that could match an empty string could cause pcregrep to loop; it
889        doesn't make sense to accept an empty string match in pcregrep, so I have
890        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
891        seems to be how GNU grep behaves.
892    
893    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
894        start or after a newline", because the conditional assertion was not being
895        correctly handled. The rule now is that both the assertion and what follows
896        in the first alternative must satisfy the test.
897    
898    9.  If auto-callout was enabled in a pattern with a conditional group whose
899        condition was an assertion, PCRE could crash during matching, both with
900        pcre_exec() and pcre_dfa_exec().
901    
902    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
903        used for matching.
904    
905    11. Unicode property support in character classes was not working for
906        characters (bytes) greater than 127 when not in UTF-8 mode.
907    
908    12. Added the -M command line option to pcretest.
909    
910    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
911    
912    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
913    
914    16. Added comments and documentation about mis-use of no_arg in the C++
915        wrapper.
916    
917    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
918        from Martin Jerabek that uses macro names for all relevant character and
919        string constants.
920    
921    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
922        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
923        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
924        these, but not everybody uses configure.
925    
926    19. A conditional group that had only one branch was not being correctly
927        recognized as an item that could match an empty string. This meant that an
928        enclosing group might also not be so recognized, causing infinite looping
929        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
930        with the subject "ab", where knowledge that the repeated group can match
931        nothing is needed in order to break the loop.
932    
933    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
934        exec(), but without supplying a callout function, matching went wrong.
935    
936    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
937        leak if the size of the offset vector was greater than 30. When the vector
938        is smaller, the saved offsets during recursion go onto a local stack
939        vector, but for larger vectors malloc() is used. It was failing to free
940        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
941        error, in fact).
942    
943    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
944        heapframe that is used only when UTF-8 support is enabled. This caused no
945        problem, but was untidy.
946    
947    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
948        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
949        included within another project.
950    
951    24. Steven Van Ingelgem's patches to add more options to the CMake support,
952        slightly modified by me:
953    
954          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
955              not building pcregrep.
956    
957          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
958              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
959    
960    25. Forward references, both numeric and by name, in patterns that made use of
961        duplicate group numbers, could behave incorrectly or give incorrect errors,
962        because when scanning forward to find the reference group, PCRE was not
963        taking into account the duplicate group numbers. A pattern such as
964        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
965    
966    26. Changed a few more instances of "const unsigned char *" to USPTR, making
967        the feature of a custom pointer more persuasive (as requested by a user).
968    
969    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
970        pcretest.c, inside #ifndefs, because it seems they are sometimes already
971        pre-defined.
972    
973    28. Added support for (*UTF8) at the start of a pattern.
974    
975    29. Arrange for flags added by the "release type" setting in CMake to be shown
976        in the configuration summary.
977    
978    
979    Version 7.8 05-Sep-08
980    ---------------------
981    
982    1.  Replaced UCP searching code with optimized version as implemented for Ad
983        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
984        stage table and inline lookup instead of a function, giving speed ups of 2
985        to 5 times on some simple patterns that I tested. Permission was given to
986        distribute the MultiStage2.py script that generates the tables (it's not in
987        the tarball, but is in the Subversion repository).
988    
989    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
990        scripts.
991    
992    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
993        a group with a zero qualifier. The result of the study could be incorrect,
994        or the function might crash, depending on the pattern.
995    
996    4.  Caseless matching was not working for non-ASCII characters in back
997        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
998        It now works when Unicode Property Support is available.
999    
1000    5.  In pcretest, an escape such as \x{de} in the data was always generating
1001        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1002        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1003        truncation.
1004    
1005    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1006    
1007    7.  Added two (int) casts to pcregrep when printing the difference of two
1008        pointers, in case they are 64-bit values.
1009    
1010    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1011        test 2 if it fails.
1012    
1013    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1014        and a #define of that name to empty if it is not externally set. This is to
1015        allow users of MSVC to set it if necessary.
1016    
1017    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1018        the convenience functions in the pcre_get.c source file.
1019    
1020    11. An option change at the start of a pattern that had top-level alternatives
1021        could cause overwriting and/or a crash. This command provoked a crash in
1022        some environments:
1023    
1024          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1025    
1026        This potential security problem was recorded as CVE-2008-2371.
1027    
1028    12. For a pattern where the match had to start at the beginning or immediately
1029        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1030        pcre_dfa_exec() could read past the end of the passed subject if there was
1031        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1032        pcretest so that it places the subject at the end of its malloc-ed buffer.
1033    
1034    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1035        exec() might read past the end of the data buffer in UTF-8 mode.
1036    
1037    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1038        the data contained the byte 0x85 as part of a UTF-8 character within its
1039        first line. This applied both to normal and DFA matching.
1040    
1041    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1042        /^[^d]*?$/8 failed to match "abc".
1043    
1044    16. Added a missing copyright notice to pcrecpp_internal.h.
1045    
1046    17. Make it more clear in the documentation that values returned from
1047        pcre_exec() in ovector are byte offsets, not character counts.
1048    
1049    18. Tidied a few places to stop certain compilers from issuing warnings.
1050    
1051    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1052        supplied by Stefan Weber. I made a further small update for 7.8 because
1053        there is a change of source arrangements: the pcre_searchfuncs.c module is
1054        replaced by pcre_ucd.c.
1055    
1056    
1057    Version 7.7 07-May-08
1058    ---------------------
1059    
1060    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1061        a string to a long long, pretend we don't even have a long long." This is
1062        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1063    
1064    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1065        pre-7.6 versions, which defined a global no_arg variable instead of putting
1066        it in the RE class. (See also #8 below.)
1067    
1068    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1069        Lopes.
1070    
1071    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1072    
1073        (1) The include/exclude patterns were being applied to the whole pathnames
1074            of files, instead of just to the final components.
1075    
1076        (2) If there was more than one level of directory, the subdirectories were
1077            skipped unless they satisfied the include/exclude conditions. This is
1078            inconsistent with GNU grep (and could even be seen as contrary to the
1079            pcregrep specification - which I improved to make it absolutely clear).
1080            The action now is always to scan all levels of directory, and just
1081            apply the include/exclude patterns to regular files.
1082    
1083    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1084        --exclude_dir in the tests to avoid scanning .svn directories.
1085    
1086    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1087        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1088        doesn't support NULs in patterns.
1089    
1090    7.  Added some missing "const"s to declarations of static tables in
1091        pcre_compile.c and pcre_dfa_exec.c.
1092    
1093    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1094        caused by fix #2  above. (Subsequently also a second patch to fix the
1095        first patch. And a third patch - this was a messy problem.)
1096    
1097    9.  Applied Craig's patch to remove the use of push_back().
1098    
1099    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1100        matching function regexec().
1101    
1102    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1103        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1104        references. PCRE supports relative numbers with this syntax (I don't think
1105        Oniguruma does).
1106    
1107    12. Previously, a group with a zero repeat such as (...){0} was completely
1108        omitted from the compiled regex. However, this means that if the group
1109        was called as a subroutine from elsewhere in the pattern, things went wrong
1110        (an internal error was given). Such groups are now left in the compiled
1111        pattern, with a new opcode that causes them to be skipped at execution
1112        time.
1113    
1114    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1115        to the way PCRE behaves:
1116    
1117        (a) A lone ] character is dis-allowed (Perl treats it as data).
1118    
1119        (b) A back reference to an unmatched subpattern matches an empty string
1120            (Perl fails the current match path).
1121    
1122        (c) A data ] in a character class must be notated as \] because if the
1123            first data character in a class is ], it defines an empty class. (In
1124            Perl it is not possible to have an empty class.) The empty class []
1125            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1126            The negative empty class [^] matches any one character, independently
1127            of the DOTALL setting.
1128    
1129    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1130        non-existent subpattern following a character class starting with ']' and
1131        containing () gave an internal compiling error instead of "reference to
1132        non-existent subpattern". Fortunately, when the pattern did exist, the
1133        compiled code was correct. (When scanning forwards to check for the
1134        existencd of the subpattern, it was treating the data ']' as terminating
1135        the class, so got the count wrong. When actually compiling, the reference
1136        was subsequently set up correctly.)
1137    
1138    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1139        it was being rejected as not supported by pcre_dfa_exec(), even though
1140        other assertions are supported. I have made pcre_dfa_exec() support
1141        (*FAIL).
1142    
1143    16. The implementation of 13c above involved the invention of a new opcode,
1144        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1145        cannot be changed at match time, I realized I could make a small
1146        improvement to matching performance by compiling OP_ALLANY instead of
1147        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1148        on the OP_ANY path.
1149    
1150    17. Compiling pcretest on Windows with readline support failed without the
1151        following two fixes: (1) Make the unistd.h include conditional on
1152        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1153    
1154    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1155        ncurses library to be included for pcretest when ReadLine support is
1156        requested, but also to allow for it to be overridden. This patch came from
1157        Daniel Bergström.
1158    
1159    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1160        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1161        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1162        spotting this.
1163    
1164    
1165    Version 7.6 28-Jan-08
1166    ---------------------
1167    
1168    1.  A character class containing a very large number of characters with
1169        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1170        overflow.
1171    
1172    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1173        HAVE_LONG_LONG is not defined.
1174    
1175    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1176        bring them up to date and include new features. This patch includes:
1177    
1178        - Fixed PH's badly added libz and libbz2 support.
1179        - Fixed a problem with static linking.
1180        - Added pcredemo. [But later removed - see 7 below.]
1181        - Fixed dftables problem and added an option.
1182        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1183            HAVE_LONG_LONG.
1184        - Added readline support for pcretest.
1185        - Added an listing of the option settings after cmake has run.
1186    
1187    4.  A user submitted a patch to Makefile that makes it easy to create
1188        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1189        Makefile.am that cause it to include this special target, without
1190        affecting anything else. Note that the same mingw target plus all
1191        the other distribution libraries and programs are now supported
1192        when configuring with CMake (see 6 below) instead of with
1193        Configure/Make.
1194    
1195    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1196        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1197        exported in the Windows port". It has not yet been confirmed that the patch
1198        solves the problem, but it does no harm.
1199    
1200    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1201        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1202        with CMake, and also correct the comment about stack recursion.
1203    
1204    7.  Remove the automatic building of pcredemo from the ./configure system and
1205        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1206        of a program that users should build themselves after PCRE is installed, so
1207        building it automatically is not really right. What is more, it gave
1208        trouble in some build environments.
1209    
1210    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1211    
1212    
1213    Version 7.5 10-Jan-08
1214    ---------------------
1215    
1216    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1217        values in parens when parsing an RE using the C++ wrapper."
1218    
1219    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1220        Characters greater than 255 were excluded from the class instead of being
1221        included.
1222    
1223    3.  The same bug as (2) above applied to negated POSIX classes such as
1224        [:^space:].
1225    
1226    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1227        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1228        I have changed it.
1229    
1230    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1231        first named subpattern) and a construct such as (?&a) would reference the
1232        first named subpattern whose name started with "a" (in other words, the
1233        length check was missing). Both these problems are fixed. "Subpattern name
1234        expected" is now given for (?&) (a zero-length name), and this patch also
1235        makes it give the same error for \k'' (previously it complained that that
1236        was a reference to a non-existent subpattern).
1237    
1238    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1239        this is right because (?- can be followed by option settings as well as by
1240        digits. I have, however, made the messages clearer.
1241    
1242    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1243        than the number used in the conditional) now cause a compile-time error.
1244        This is actually not compatible with Perl, which accepts such patterns, but
1245        treats the conditional as always being FALSE (as PCRE used to), but it
1246        seems to me that giving a diagnostic is better.
1247    
1248    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1249        and messages.
1250    
1251    9.  Fix two occurrences of "backslash" in comments that should have been
1252        "backspace".
1253    
1254    10. Remove two redundant lines of code that can never be obeyed (their function
1255        was moved elsewhere).
1256    
1257    11. The program that makes PCRE's Unicode character property table had a bug
1258        which caused it to generate incorrect table entries for sequences of
1259        characters that have the same character type, but are in different scripts.
1260        It amalgamated them into a single range, with the script of the first of
1261        them. In other words, some characters were in the wrong script. There were
1262        thirteen such cases, affecting characters in the following ranges:
1263    
1264          U+002b0 - U+002c1
1265          U+0060c - U+0060d
1266          U+0061e - U+00612
1267          U+0064b - U+0065e
1268          U+0074d - U+0076d
1269          U+01800 - U+01805
1270          U+01d00 - U+01d77
1271          U+01d9b - U+01dbf
1272          U+0200b - U+0200f
1273          U+030fc - U+030fe
1274          U+03260 - U+0327f
1275          U+0fb46 - U+0fbb1
1276          U+10450 - U+1049d
1277    
1278    12. The -o option (show only the matching part of a line) for pcregrep was not
1279        compatible with GNU grep in that, if there was more than one match in a
1280        line, it showed only the first of them. It now behaves in the same way as
1281        GNU grep.
1282    
1283    13. If the -o and -v options were combined for pcregrep, it printed a blank
1284        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1285        does the same. The return code can be used to tell if there were any
1286        non-matching lines.
1287    
1288    14. Added --file-offsets and --line-offsets to pcregrep.
1289    
1290    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1291        infinitely looping recursion. The bug was that positive lookaheads were not
1292        being skipped when checking for a possible empty match (negative lookaheads
1293        and both kinds of lookbehind were skipped).
1294    
1295    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1296        inclusion of <windows.h> to before rather than after the definition of
1297        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1298    
1299    17. Specifying a possessive quantifier with a specific limit for a Unicode
1300        character property caused pcre_compile() to compile bad code, which led at
1301        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1302        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1303        caused the error; without that there was no problem.
1304    
1305    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1306    
1307    19. Added --enable-pcretest-libreadline.
1308    
1309    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1310        RE::GlobalReplace(). As a result, the number of replacements returned was
1311        double what it should be. I removed one of the increments, but Craig sent a
1312        later patch that removed the other one (the right fix) and added unit tests
1313        that check the return values (which was not done before).
1314    
1315    21. Several CMake things:
1316    
1317        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1318            the names libpcre and libpcreposix, not just pcre and pcreposix.
1319    
1320        (2) The above change means that pcretest and pcregrep are now correctly
1321            linked with the newly-built libraries, not previously installed ones.
1322    
1323        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1324    
1325    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1326        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1327        UTF-8 newline character). The key issue is that the pattern starts .*;
1328        this means that the match must be either at the beginning, or after a
1329        newline. The bug was in the code for advancing after a failed match and
1330        checking that the new position followed a newline. It was not taking
1331        account of UTF-8 characters correctly.
1332    
1333    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1334        character classes. PCRE was not treating the sequence [:...:] as a
1335        character class unless the ... were all letters. Perl, however, seems to
1336        allow any characters between [: and :], though of course it rejects as
1337        unknown any "names" that contain non-letters, because all the known class
1338        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1339        for example, whereas PCRE did not - it did not recognize a POSIX character
1340        class. This seemed a bit dangerous, so the code has been changed to be
1341        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1342        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1343        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1344        Perl does, and where it didn't before.
1345    
1346    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1347        Windows environments %n is disabled by default.
1348    
1349    
1350    Version 7.4 21-Sep-07
1351    ---------------------
1352    
1353    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1354        means that a class such as [\s] counted as "explicit reference to CR or
1355        LF". That isn't really right - the whole point of the change was to try to
1356        help when there was an actual mention of one of the two characters. So now
1357        the change happens only if \r or \n (or a literal CR or LF) character is
1358        encountered.
1359    
1360    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1361        of both had grown to the point where there were only 3 bits left.
1362        Fortunately, there was spare space in the data structure, and so I have
1363        moved the internal flags into a new 16-bit field to free up more option
1364        bits.
1365    
1366    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1367        but did not set the internal JCHANGED flag - either of these is enough to
1368        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1369        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1370        start sets both bits.
1371    
1372    4.  Added options (at build time, compile time, exec time) to change \R from
1373        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1374    
1375    5.  doc/pcresyntax.html was missing from the distribution.
1376    
1377    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1378        compatibility, even though it is no longer used.
1379    
1380    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1381        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1382        windows.h file is present (where different names are used). [This was
1383        reversed later after testing - see 16 below.]
1384    
1385    8.  Changed all #include <config.h> to #include "config.h". There were also
1386        some further <pcre.h> cases that I changed to "pcre.h".
1387    
1388    9.  When pcregrep was used with the --colour option, it missed the line ending
1389        sequence off the lines that it output.
1390    
1391    10. It was pointed out to me that arrays of string pointers cause lots of
1392        relocations when a shared library is dynamically loaded. A technique of
1393        using a single long string with a table of offsets can drastically reduce
1394        these. I have refactored PCRE in four places to do this. The result is
1395        dramatic:
1396    
1397          Originally:                          290
1398          After changing UCP table:            187
1399          After changing error message table:   43
1400          After changing table of "verbs"       36
1401          After changing table of Posix names   22
1402    
1403        Thanks to the folks working on Gregex for glib for this insight.
1404    
1405    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1406        unicode-properties was also set.
1407    
1408    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1409    
1410    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1411        checked only for CRLF.
1412    
1413    14. Added casts to pcretest.c to avoid compiler warnings.
1414    
1415    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1416    
1417    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1418        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1419        entirely. This removes changes made in 7 above.
1420    
1421    17. The CMake files have been updated, and there is now more information about
1422        building with CMake in the NON-UNIX-USE document.
1423    
1424    
1425    Version 7.3 28-Aug-07
1426    ---------------------
1427    
1428     1. In the rejigging of the build system that eventually resulted in 7.1, the
1429        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1430        brackets there is not right, since it causes compilers to look for an
1431        installed pcre.h, not the version that is in the source that is being
1432        compiled (which of course may be different). I have changed it back to:
1433    
1434          #include "pcre.h"
1435    
1436        I have a vague recollection that the change was concerned with compiling in
1437        different directories, but in the new build system, that is taken care of
1438        by the VPATH setting the Makefile.
1439    
1440     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1441        when the subject happened to end in the byte 0x85 (e.g. if the last
1442        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1443        characters but of course it shouldn't be taken as a newline when it is part
1444        of another character. The bug was that, for an unlimited repeat of . in
1445        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1446        characters when looking for a newline.
1447    
1448     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1449    
1450     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1451        in debug output.
1452    
1453     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1454        long printing in the pcrecpp unittest when running under MinGW.
1455    
1456     6. ESC_K was left out of the EBCDIC table.
1457    
1458     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1459        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1460        limit also applies to "virtual nesting" when a pattern is recursive, and in
1461        this case 1000 isn't so big. I have been able to remove this limit at the
1462        expense of backing off one optimization in certain circumstances. Normally,
1463        when pcre_exec() would call its internal match() function recursively and
1464        immediately return the result unconditionally, it uses a "tail recursion"
1465        feature to save stack. However, when a subpattern that can match an empty
1466        string has an unlimited repetition quantifier, it no longer makes this
1467        optimization. That gives it a stack frame in which to save the data for
1468        checking that an empty string has been matched. Previously this was taken
1469        from the 1000-entry workspace that had been reserved. So now there is no
1470        explicit limit, but more stack is used.
1471    
1472     8. Applied Daniel's patches to solve problems with the import/export magic
1473        syntax that is required for Windows, and which was going wrong for the
1474        pcreposix and pcrecpp parts of the library. These were overlooked when this
1475        problem was solved for the main library.
1476    
1477     9. There were some crude static tests to avoid integer overflow when computing
1478        the size of patterns that contain repeated groups with explicit upper
1479        limits. As the maximum quantifier is 65535, the maximum group length was
1480        set at 30,000 so that the product of these two numbers did not overflow a
1481        32-bit integer. However, it turns out that people want to use groups that
1482        are longer than 30,000 bytes (though not repeat them that many times).
1483        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1484        made it possible to implement the integer overflow checks in a much more
1485        dynamic way, which I have now done. The artificial limitation on group
1486        length has been removed - we now have only the limit on the total length of
1487        the compiled pattern, which depends on the LINK_SIZE setting.
1488    
1489    10. Fixed a bug in the documentation for get/copy named substring when
1490        duplicate names are permitted. If none of the named substrings are set, the
1491        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1492        empty string.
1493    
1494    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1495        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1496        because the ] is interpreted as the first data character and the
1497        terminating ] is not found. PCRE has been made compatible with Perl in this
1498        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1499        cause memory overwriting.
1500    
1501    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1502        string has been matched (to stop an infinite loop). It was not recognizing
1503        a conditional subpattern that could match an empty string if that
1504        subpattern was within another subpattern. For example, it looped when
1505        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1506        condition was not nested. This bug has been fixed.
1507    
1508    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1509        past the start of the subject in the presence of bytes with the top bit
1510        set, for example "\x8aBCD".
1511    
1512    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1513        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1514    
1515    14. Optimized (?!) to (*FAIL).
1516    
1517    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1518        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1519        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1520        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1521        does: it's just the validity check that is more restrictive.
1522    
1523    16. Inserted checks for integer overflows during escape sequence (backslash)
1524        processing, and also fixed erroneous offset values for syntax errors during
1525        backslash processing.
1526    
1527    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1528        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1529    
1530    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1531        caused an overrun.
1532    
1533    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1534        something other than just ASCII characters) inside a group that had an
1535        unlimited repeat caused a loop at compile time (while checking to see
1536        whether the group could match an empty string).
1537    
1538    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1539        [\P{Any}] did so. (Error in the code for printing property names.)
1540    
1541    21. An orphan \E inside a character class could cause a crash.
1542    
1543    22. A repeated capturing bracket such as (A)? could cause a wild memory
1544        reference during compilation.
1545    
1546    23. There are several functions in pcre_compile() that scan along a compiled
1547        expression for various reasons (e.g. to see if it's fixed length for look
1548        behind). There were bugs in these functions when a repeated \p or \P was
1549        present in the pattern. These operators have additional parameters compared
1550        with \d, etc, and these were not being taken into account when moving along
1551        the compiled data. Specifically:
1552    
1553        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1554            length.
1555    
1556        (b) An item such as \pL+ within a repeated group could cause crashes or
1557            loops.
1558    
1559        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1560            "reference to non-existent subpattern" error.
1561    
1562        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1563    
1564    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1565        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1566    
1567    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1568    
1569    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1570        character were causing crashes (broken optimization).
1571    
1572    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1573        \p or \P) caused a compile-time loop.
1574    
1575    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1576        break. For example, the unstudied pattern [\r\n]A does not match the string
1577        "\r\nA" because change 7.0/46 below moves the current point on by two
1578        characters after failing to match at the start. However, the pattern \nA
1579        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1580        the same is true. There doesn't seem any very clean way out of this, but
1581        what I have chosen to do makes the common cases work: PCRE now takes note
1582        of whether there can be an explicit match for \r or \n anywhere in the
1583        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1584        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1585        pattern has explicit CR or LF references.
1586    
1587    29. Added (*CR) etc for changing newline setting at start of pattern.
1588    
1589    
1590    Version 7.2 19-Jun-07
1591    ---------------------
1592    
1593     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1594        which is apparently normally available under Windows.
1595    
1596     2. Re-jig the pcregrep tests with different newline settings in an attempt
1597        to make them independent of the local environment's newline setting.
1598    
1599     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1600    
1601     4. Some of the "internals" tests were previously cut out when the link size
1602        was not 2, because the output contained actual offsets. The recent new
1603        "Z" feature of pcretest means that these can be cut out, making the tests
1604        usable with all link sizes.
1605    
1606     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1607        stack recursion. This gives a massive performance boost under BSD, but just
1608        a small improvement under Linux. However, it saves one field in the frame
1609        in all cases.
1610    
1611     6. Added more features from the forthcoming Perl 5.10:
1612    
1613        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1614            recursion call. It refers to the nth most recently opened parentheses.
1615    
1616        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1617            to be opened parentheses.
1618    
1619        (c) Conditions that refer to capturing parentheses can be specified
1620            relatively, for example, (?(-2)... or (?(+3)...
1621    
1622        (d) \K resets the start of the current match so that everything before
1623            is not part of it.
1624    
1625        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1626    
1627        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1628            reference syntax.
1629    
1630        (g) (?| introduces a group in which the numbering of parentheses in each
1631            alternative starts with the same number.
1632    
1633        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1634    
1635     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1636        PCRE_INFO_JCHANGED.
1637    
1638     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1639        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1640        for detecting groups that can match an empty string.
1641    
1642     9. A pattern with a very large number of alternatives (more than several
1643        hundred) was running out of internal workspace during the pre-compile
1644        phase, where pcre_compile() figures out how much memory will be needed. A
1645        bit of new cunning has reduced the workspace needed for groups with
1646        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1647        workspace instead of running out of the 4096 that are available.
1648    
1649    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1650    
1651    11. Applied patch from Google to remove an optimization that didn't quite work.
1652        The report of the bug said:
1653    
1654          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1655          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1656          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1657    
1658    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1659        it matched the wrong number of bytes.
1660    
1661    
1662    Version 7.1 24-Apr-07
1663    ---------------------
1664    
1665     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1666        that is more "standard", making use of automake and other Autotools. There
1667        is some re-arrangement of the files and adjustment of comments consequent
1668        on this.
1669    
1670     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1671        for recursive directory scanning broke on some systems because the files
1672        are not scanned in any specific order and on different systems the order
1673        was different. A call to "sort" has been inserted into RunGrepTest for the
1674        approprate test as a short-term fix. In the longer term there may be an
1675        alternative.
1676    
1677     3. I had an email from Eric Raymond about problems translating some of PCRE's
1678        man pages to HTML (despite the fact that I distribute HTML pages, some
1679        people do their own conversions for various reasons). The problems
1680        concerned the use of low-level troff macros .br and .in. I have therefore
1681        removed all such uses from the man pages (some were redundant, some could
1682        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1683        HTML has been updated to handle .nf/.fi and to complain if it encounters
1684        .br or .in.
1685    
1686     4. Updated comments in configure.ac that get placed in config.h.in and also
1687        arranged for config.h to be included in the distribution, with the name
1688        config.h.generic, for the benefit of those who have to compile without
1689        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1690    
1691     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1692        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1693        makevp.bat for the current PCRE, using the additional files
1694        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1695    
1696     6. A Windows user reported a minor discrepancy with test 2, which turned out
1697        to be caused by a trailing space on an input line that had got lost in his
1698        copy. The trailing space was an accident, so I've just removed it.
1699    
1700     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1701        that is needed.
1702    
1703     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1704        as "const" (a) because they are and (b) because it helps the PHP
1705        maintainers who have recently made a script to detect big data structures
1706        in the php code that should be moved to the .rodata section. I remembered
1707        to update Builducptable as well, so it won't revert if ucptable.h is ever
1708        re-created.
1709    
1710     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1711        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1712        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1713        support is not required. This saves 1.5-2K of code, which is important in
1714        some applications.
1715    
1716        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1717        so as not to refer to the tables, even though these functions will never be
1718        called when UTF-8 support is disabled. Otherwise there are problems with a
1719        shared library.
1720    
1721    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1722    
1723        (a) It was defining its arguments as char * instead of void *.
1724    
1725        (b) It was assuming that all moves were upwards in memory; this was true
1726            a long time ago when I wrote it, but is no longer the case.
1727    
1728        The emulated memove() is provided for those environments that have neither
1729        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1730        is clearly not the case, as these two bugs were recently reported.
1731    
1732    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1733        and Detrail to create the HTML documentation, the .txt form of the man
1734        pages, and it removes trailing spaces from listed files. It also creates
1735        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1736        case, it wraps all the #defines with #ifndefs. This script should be run
1737        before "make dist".
1738    
1739    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1740        with Unicode property support.
1741    
1742        (a) For a maximizing quantifier, if the two different cases of the
1743            character were of different lengths in their UTF-8 codings (there are
1744            some cases like this - I found 11), and the matching function had to
1745            back up over a mixture of the two cases, it incorrectly assumed they
1746            were both the same length.
1747    
1748        (b) When PCRE was configured to use the heap rather than the stack for
1749            recursion during matching, it was not correctly preserving the data for
1750            the other case of a UTF-8 character when checking ahead for a match
1751            while processing a minimizing repeat. If the check also involved
1752            matching a wide character, but failed, corruption could cause an
1753            erroneous result when trying to check for a repeat of the original
1754            character.
1755    
1756    13. Some tidying changes to the testing mechanism:
1757    
1758        (a) The RunTest script now detects the internal link size and whether there
1759            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1760            values substituted by "configure". (The RunGrepTest script already did
1761            this for UTF-8.) The configure.ac script no longer substitutes the
1762            relevant variables.
1763    
1764        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1765            with length and offset values. This means that the output is different
1766            for different internal link sizes. Test 2 is skipped for link sizes
1767            other than 2 because of this, bypassing the problem. Unfortunately,
1768            there was also a test in test 3 (the locale tests) that used /B and
1769            failed for link sizes other than 2. Rather than cut the whole test out,
1770            I have added a new /Z option to pcretest that replaces the length and
1771            offset values with spaces. This is now used to make test 3 independent
1772            of link size. (Test 2 will be tidied up later.)
1773    
1774    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1775        segmentation fault instead of returning the appropriate error message.
1776    
1777    15. In multiline mode when the newline sequence was set to "any", the pattern
1778        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1779        This doesn't seem right; it now treats the CRLF combination as the line
1780        ending, and so does not match in that case. It's only a pattern such as ^$
1781        that would hit this one: something like ^ABC$ would have failed after \r
1782        and then tried again after \r\n.
1783    
1784    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1785        in an attempt to make files that differ only in their line terminators
1786        compare equal. This works on Linux.
1787    
1788    17. Under certain error circumstances pcregrep might try to free random memory
1789        as it exited. This is now fixed, thanks to valgrind.
1790    
1791    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1792        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1793        was because its rules for how to advance for /g after matching an empty
1794        string at the end of a line did not allow for this case. They now check for
1795        it specially.
1796    
1797    20. pcretest is supposed to handle patterns and data of any length, by
1798        extending its buffers when necessary. It was getting this wrong when the
1799        buffer for a data line had to be extended.
1800    
1801    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1802        CRLF as a newline sequence.
1803    
1804    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1805        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1806        I have nevertheless tidied it up.
1807    
1808    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1809    
1810    24. Added a man page for pcre-config.
1811    
1812    
1813    Version 7.0 19-Dec-06
1814    ---------------------
1815    
1816     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1817        moving to gcc 4.1.1.
1818    
1819     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1820        sys/time.h, which is documented as needed for this function. It doesn't
1821        seem to matter on Linux, but it showed up on some releases of OS X.
1822    
1823     3. It seems that there are systems where bytes whose values are greater than
1824        127 match isprint() in the "C" locale. The "C" locale should be the
1825        default when a C program starts up. In most systems, only ASCII printing
1826        characters match isprint(). This difference caused the output from pcretest
1827        to vary, making some of the tests fail. I have changed pcretest so that:
1828    
1829        (a) When it is outputting text in the compiled version of a pattern, bytes
1830            other than 32-126 are always shown as hex escapes.
1831    
1832        (b) When it is outputting text that is a matched part of a subject string,
1833            it does the same, unless a different locale has been set for the match
1834            (using the /L modifier). In this case, it uses isprint() to decide.
1835    
1836     4. Fixed a major bug that caused incorrect computation of the amount of memory
1837        required for a compiled pattern when options that changed within the
1838        pattern affected the logic of the preliminary scan that determines the
1839        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1840        that the computed length was too small. The symptoms of this bug were
1841        either the PCRE error "internal error: code overflow" from pcre_compile(),
1842        or a glibc crash with a message such as "pcretest: free(): invalid next
1843        size (fast)". Examples of patterns that provoked this bug (shown in
1844        pcretest format) are:
1845    
1846          /(?-x: )/x
1847          /(?x)(?-x: \s*#\s*)/
1848          /((?i)[\x{c0}])/8
1849          /(?i:[\x{c0}])/8
1850    
1851        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1852        is now done differently.
1853    
1854     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1855        wrapper classes; (b) implement a new function in the C++ scanner that is
1856        more efficient than the old way of doing things because it avoids levels of
1857        recursion in the regex matching; (c) add a paragraph to the documentation
1858        for the FullMatch() function.
1859    
1860     6. The escape sequence \n was being treated as whatever was defined as
1861        "newline". Not only was this contrary to the documentation, which states
1862        that \n is character 10 (hex 0A), but it also went horribly wrong when
1863        "newline" was defined as CRLF. This has been fixed.
1864    
1865     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1866        was being set to -1 for the "end of line" case (supposedly a value that no
1867        character can have). Though this value is never used (the check for end of
1868        line is "zero bytes in current character"), it caused compiler complaints.
1869        I've changed it to 0xffffffff.
1870    
1871     8. In pcre_version.c, the version string was being built by a sequence of
1872        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1873        string (as it is for production releases) called a macro with an empty
1874        argument. The C standard says the result of this is undefined. The gcc
1875        compiler treats it as an empty string (which was what was wanted) but it is
1876        reported that Visual C gives an error. The source has been hacked around to
1877        avoid this problem.
1878    
1879     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1880        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1881        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1882        of them did).
1883    
1884    10. Originally, pcretest opened its input and output without "b"; then I was
1885        told that "b" was needed in some environments, so it was added for release
1886        5.0 to both the input and output. (It makes no difference on Unix-like
1887        systems.) Later I was told that it is wrong for the input on Windows. I've
1888        now abstracted the modes into two macros, to make it easier to fiddle with
1889        them, and removed "b" from the input mode under Windows.
1890    
1891    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1892    
1893    12. Added -help and --help to pcretest as an official way of being reminded
1894        of the options.
1895    
1896    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1897        and pcrecpp.cc because they annoy compilers at high warning levels.
1898    
1899    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1900    
1901    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1902        scripts are not C programs :-) and which was not noticed because it works
1903        on Linux.
1904    
1905    16. pcretest is supposed to handle any length of pattern and data line (as one
1906        line or as a continued sequence of lines) by extending its input buffer if
1907        necessary. This feature was broken for very long pattern lines, leading to
1908        a string of junk being passed to pcre_compile() if the pattern was longer
1909        than about 50K.
1910    
1911    17. I have done a major re-factoring of the way pcre_compile() computes the
1912        amount of memory needed for a compiled pattern. Previously, there was code
1913        that made a preliminary scan of the pattern in order to do this. That was
1914        OK when PCRE was new, but as the facilities have expanded, it has become
1915        harder and harder to keep it in step with the real compile phase, and there
1916        have been a number of bugs (see for example, 4 above). I have now found a
1917        cunning way of running the real compile function in a "fake" mode that
1918        enables it to compute how much memory it would need, while actually only
1919        ever using a few hundred bytes of working memory and without too many
1920        tests of the mode. This should make future maintenance and development
1921        easier. A side effect of this work is that the limit of 200 on the nesting
1922        depth of parentheses has been removed (though this was never a serious
1923        limitation, I suspect). However, there is a downside: pcre_compile() now
1924        runs more slowly than before (30% or more, depending on the pattern). I
1925        hope this isn't a big issue. There is no effect on runtime performance.
1926    
1927    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1928        newline (only possible for the last line of a file) and it was a
1929        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1930    
1931    19. Added additional timing features to pcretest. (1) The -tm option now times
1932        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1933        separate command line item, by a number that specifies the number of
1934        repeats to use when timing. The default is 50000; this gives better
1935        precision, but takes uncomfortably long for very large patterns.
1936    
1937    20. Extended pcre_study() to be more clever in cases where a branch of a
1938        subpattern has no definite first character. For example, (a*|b*)[cd] would
1939        previously give no result from pcre_study(). Now it recognizes that the
1940        first character must be a, b, c, or d.
1941    
1942    21. There was an incorrect error "recursive call could loop indefinitely" if
1943        a subpattern (or the entire pattern) that was being tested for matching an
1944        empty string contained only one non-empty item after a nested subpattern.
1945        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1946        incorrectly, because the \d was being skipped in the check.
1947    
1948    22. The pcretest program now has a new pattern option /B and a command line
1949        option -b, which is equivalent to adding /B to every pattern. This causes
1950        it to show the compiled bytecode, without the additional information that
1951        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1952        is the same as /B/I).
1953    
1954    23. A new optimization is now able automatically to treat some sequences such
1955        as a*b as a*+b. More specifically, if something simple (such as a character
1956        or a simple class like \d) has an unlimited quantifier, and is followed by
1957        something that cannot possibly match the quantified thing, the quantifier
1958        is automatically "possessified".
1959    
1960    24. A recursive reference to a subpattern whose number was greater than 39
1961        went wrong under certain circumstances in UTF-8 mode. This bug could also
1962        have affected the operation of pcre_study().
1963    
1964    25. Realized that a little bit of performance could be had by replacing
1965        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1966    
1967    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1968    
1969    27. Possessive quantifiers such as a++ were previously implemented by turning
1970        them into atomic groups such as ($>a+). Now they have their own opcodes,
1971        which improves performance. This includes the automatically created ones
1972        from 23 above.
1973    
1974    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1975        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1976        the first matched character to be a colon. This applied both to named and
1977        numbered groups.
1978    
1979    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1980    
1981    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1982        building PCRE on Windows easier, so I have included it in the distribution.
1983    
1984    31. There is now a check in pcretest against a ridiculously large number being
1985        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1986        loop, the loop is abandoned.
1987    
1988    32. Forward references to subpatterns in conditions such as (?(2)...) where
1989        subpattern 2 is defined later cause pcre_compile() to search forwards in
1990        the pattern for the relevant set of parentheses. This search went wrong
1991        when there were unescaped parentheses in a character class, parentheses
1992        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1993    
1994    33. "Subroutine" calls and backreferences were previously restricted to
1995        referencing subpatterns earlier in the regex. This restriction has now
1996        been removed.
1997    
1998    34. Added a number of extra features that are going to be in Perl 5.10. On the
1999        whole, these are just syntactic alternatives for features that PCRE had
2000        previously implemented using the Python syntax or my own invention. The
2001        other formats are all retained for compatibility.
2002    
2003        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2004            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2005            also .NET compatible.
2006    
2007        (b) A recursion or subroutine call to a named group can now be defined as
2008            (?&name) as well as (?P>name).
2009    
2010        (c) A backreference to a named group can now be defined as \k<name> or
2011            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2012            5.10, are also .NET compatible.
2013    
2014        (d) A conditional reference to a named group can now use the syntax
2015            (?(<name>) or (?('name') as well as (?(name).
2016    
2017        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2018            groups (named and numbered) that are never evaluated inline, but can be
2019            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2020            is always false. There may be only one alternative in such a group.
2021    
2022        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2023            as the simple (?(R). The condition is true only if the most recent
2024            recursion is that of the given number or name. It does not search out
2025            through the entire recursion stack.
2026    
2027        (g) The escape \gN or \g{N} has been added, where N is a positive or
2028            negative number, specifying an absolute or relative reference.
2029    
2030    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2031        some "unreachable code" warnings.
2032    
2033    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2034        things, this adds five new scripts.
2035    
2036    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2037        There were also incompatibilities regarding the handling of \Q..\E inside
2038        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2039        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2040    
2041    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2042        matches an empty string, and forcibly breaks the loop. There were bugs in
2043        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2044        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2045        separate and independent bugs (that affected different cases) have been
2046        fixed.
2047    
2048    39. Refactored the code to abolish the use of different opcodes for small
2049        capturing bracket numbers. This is a tidy that I avoided doing when I
2050        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2051        The new approach is not only tidier, it makes it possible to reduce the
2052        memory needed to fix the previous bug (38).
2053    
2054    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2055        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2056        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2057        mode.
2058    
2059    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2060        report.
2061    
2062    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2063        copy construction and assignment in the C++ wrapper.
2064    
2065    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2066        couple of bugs that could have given wrong results in the "--newline=crlf"
2067        case.
2068    
2069    44. Added a number of casts and did some reorganization of signed/unsigned int
2070        variables following suggestions from Dair Grant. Also renamed the variable
2071        "this" as "item" because it is a C++ keyword.
2072    
2073    45. Arranged for dftables to add
2074    
2075          #include "pcre_internal.h"
2076    
2077        to pcre_chartables.c because without it, gcc 4.x may remove the array
2078        definition from the final binary if PCRE is built into a static library and
2079        dead code stripping is activated.
2080    
2081    46. For an unanchored pattern, if a match attempt fails at the start of a
2082        newline sequence, and the newline setting is CRLF or ANY, and the next two
2083        characters are CRLF, advance by two characters instead of one.
2084    
2085    
2086    Version 6.7 04-Jul-06
2087    ---------------------
2088    
2089     1. In order to handle tests when input lines are enormously long, pcretest has
2090        been re-factored so that it automatically extends its buffers when
2091        necessary. The code is crude, but this _is_ just a test program. The
2092        default size has been increased from 32K to 50K.
2093    
2094     2. The code in pcre_study() was using the value of the re argument before
2095        testing it for NULL. (Of course, in any sensible call of the function, it
2096        won't be NULL.)
2097    
2098     3. The memmove() emulation function in pcre_internal.h, which is used on
2099        systems that lack both memmove() and bcopy() - that is, hardly ever -
2100        was missing a "static" storage class specifier.
2101    
2102     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2103        containing an extended class (one that cannot be represented by a bitmap
2104        because it contains high-valued characters or Unicode property items, e.g.
2105        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2106        pattern, but PCRE should not loop if you do not (it no longer does).
2107        [Detail: two cases were found: (a) a repeated subpattern containing an
2108        extended class; (b) a recursive reference to a subpattern that followed a
2109        previous extended class. It wasn't skipping over the extended class
2110        correctly when UTF-8 mode was not set.]
2111    
2112     5. A negated single-character class was not being recognized as fixed-length
2113        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2114        compile error "lookbehind assertion is not fixed length".
2115    
2116     6. The RunPerlTest auxiliary script was showing an unexpected difference
2117        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2118        write a Perl script that can interpret lines of an input file either as
2119        byte characters or as UTF-8, which is what "perltest" was being required to
2120        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2121        can't do is switch easily at run time between having the "use utf8;" pragma
2122        or not. In the end, I fudged it by using the RunPerlTest script to insert
2123        "use utf8;" explicitly for the UTF-8 tests.
2124    
2125     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2126        the end of the subject string, contrary to the documentation and to what
2127        Perl does. This was true of both matching functions. Now it matches only at
2128        the start of the subject and immediately after *internal* newlines.
2129    
2130     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2131        a pointer to an int instead of a pointer to an unsigned long int. This
2132        caused problems on 64-bit systems.
2133    
2134     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2135        instance of the 'standard' template library not being so standard".
2136    
2137    10. There was no check on the number of named subpatterns nor the maximum
2138        length of a subpattern name. The product of these values is used to compute
2139        the size of the memory block for a compiled pattern. By supplying a very
2140        long subpattern name and a large number of named subpatterns, the size
2141        computation could be caused to overflow. This is now prevented by limiting
2142        the length of names to 32 characters, and the number of named subpatterns
2143        to 10,000.
2144    
2145    11. Subpatterns that are repeated with specific counts have to be replicated in
2146        the compiled pattern. The size of memory for this was computed from the
2147        length of the subpattern and the repeat count. The latter is limited to
2148        65535, but there was no limit on the former, meaning that integer overflow
2149        could in principle occur. The compiled length of a repeated subpattern is
2150        now limited to 30,000 bytes in order to prevent this.
2151    
2152    12. Added the optional facility to have named substrings with the same name.
2153    
2154    13. Added the ability to use a named substring as a condition, using the
2155        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2156        are numbers (not recommended). Forward references are permitted.
2157    
2158    14. Added forward references in named backreferences (if you see what I mean).
2159    
2160    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2161        pattern could run off the end of the subject. For example, the pattern
2162        "(?s)(.{1,5})"8 did this with the subject "ab".
2163    
2164    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2165        PCRE_CASELESS was set when matching characters that were quantified with ?
2166        or *.
2167    
2168    17. A character class other than a single negated character that had a minimum
2169        but no maximum quantifier - for example [ab]{6,} - was not handled
2170        correctly by pce_dfa_exec(). It would match only one character.
2171    
2172    18. A valid (though odd) pattern that looked like a POSIX character
2173        class but used an invalid character after [ (for example [[,abc,]]) caused
2174        pcre_compile() to give the error "Failed: internal error: code overflow" or
2175        in some cases to crash with a glibc free() error. This could even happen if
2176        the pattern terminated after [[ but there just happened to be a sequence of
2177        letters, a binary zero, and a closing ] in the memory that followed.
2178    
2179    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2180        over the years. Originally (before any Unicode support), just the bottom 8
2181        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2182        output from "man perlunicode" includes this:
2183    
2184          The regular expression compiler produces polymorphic opcodes.  That
2185          is, the pattern adapts to the data and automatically switches to
2186          the Unicode character scheme when presented with Unicode data--or
2187          instead uses a traditional byte scheme when presented with byte
2188          data.
2189    
2190        Sadly, a wide octal escape does not cause a switch, and in a string with
2191        no other multibyte characters, these octal escapes are treated as before.
2192        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2193        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2194        Unicode string.
2195    
2196        I have not perpetrated such confusion in PCRE. Up till now, it took just
2197        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2198        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2199        translate to the appropriate multibyte character.
2200    
2201    29. Applied some refactoring to reduce the number of warnings from Microsoft
2202        and Borland compilers. This has included removing the fudge introduced
2203        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2204        a warning about an unused variable.
2205    
2206    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2207        characters since release 4.0, because Perl (from release 5.004) does not.
2208        [Or at least, is documented not to: some releases seem to be in conflict
2209        with the documentation.] However, when a pattern was studied with
2210        pcre_study() and all its branches started with \s, PCRE still included VT
2211        as a possible starting character. Of course, this did no harm; it just
2212        caused an unnecessary match attempt.
2213    
2214    22. Removed a now-redundant internal flag bit that recorded the fact that case
2215        dependency changed within the pattern. This was once needed for "required
2216        byte" processing, but is no longer used. This recovers a now-scarce options
2217        bit. Also moved the least significant internal flag bit to the most-
2218        significant bit of the word, which was not previously used (hangover from
2219        the days when it was an int rather than a uint) to free up another bit for
2220        the future.
2221    
2222    23. Added support for CRLF line endings as well as CR and LF. As well as the
2223        default being selectable at build time, it can now be changed at runtime
2224        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2225        specify that it is scanning data with non-default line endings.
2226    
2227    24. Changed the definition of CXXLINK to make it agree with the definition of
2228        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2229    
2230    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2231        recursions. This makes a big different to stack usage for some patterns.
2232    
2233    26. If a subpattern containing a named recursion or subroutine reference such
2234        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2235        the space required for the compiled pattern went wrong and gave too small a
2236        value. Depending on the environment, this could lead to "Failed: internal
2237        error: code overflow at offset 49" or "glibc detected double free or
2238        corruption" errors.
2239    
2240    27. Applied patches from Google (a) to support the new newline modes and (b) to
2241        advance over multibyte UTF-8 characters in GlobalReplace.
2242    
2243    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2244        difference for some implementation of PCRE in some Windows version.
2245    
2246    29. Added some extra testing facilities to pcretest:
2247    
2248        \q<number>   in a data line sets the "match limit" value
2249        \Q<number>   in a data line sets the "match recursion limt" value
2250        -S <number>  sets the stack size, where <number> is in megabytes
2251    
2252        The -S option isn't available for Windows.
2253    
2254    
2255    Version 6.6 06-Feb-06
2256    ---------------------
2257    
2258     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2259        in pcreposix.h. I have copied the definition from pcre.h.
2260    
2261     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2262        because pcre.h is no longer a built file.
2263    
2264     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2265        not normally included in the compiled code.
2266    
2267    
2268    Version 6.5 01-Feb-06
2269    ---------------------
2270    
2271     1. When using the partial match feature with pcre_dfa_exec(), it was not
2272        anchoring the second and subsequent partial matches at the new starting
2273        point. This could lead to incorrect results. For example, with the pattern
2274        /1234/, partially matching against "123" and then "a4" gave a match.
2275    
2276     2. Changes to pcregrep:
2277    
2278        (a) All non-match returns from pcre_exec() were being treated as failures
2279            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2280            error message is output. Some extra information is given for the
2281            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2282            probably the only errors that are likely to be caused by users (by
2283            specifying a regex that has nested indefinite repeats, for instance).
2284            If there are more than 20 of these errors, pcregrep is abandoned.
2285    
2286        (b) A binary zero was treated as data while matching, but terminated the
2287            output line if it was written out. This has been fixed: binary zeroes
2288            are now no different to any other data bytes.
2289    
2290        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2291            used to set a locale for matching. The --locale=xxxx long option has
2292            been added (no short equivalent) to specify a locale explicitly on the
2293            pcregrep command, overriding the environment variables.
2294    
2295        (d) When -B was used with -n, some line numbers in the output were one less
2296            than they should have been.
2297    
2298        (e) Added the -o (--only-matching) option.
2299    
2300        (f) If -A or -C was used with -c (count only), some lines of context were
2301            accidentally printed for the final match.
2302    
2303        (g) Added the -H (--with-filename) option.
2304    
2305        (h) The combination of options -rh failed to suppress file names for files
2306            that were found from directory arguments.
2307    
2308        (i) Added the -D (--devices) and -d (--directories) options.
2309    
2310        (j) Added the -F (--fixed-strings) option.
2311    
2312        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2313    
2314        (l) Added the --colo(u)r option.
2315    
2316        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2317            is not present by default.
2318    
2319     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2320        items such as (?R) or (?1), when the recursion could match a number of
2321        alternatives. If it matched one of the alternatives, but subsequently,
2322        outside the recursion, there was a failure, the code tried to back up into
2323        the recursion. However, because of the way PCRE is implemented, this is not
2324        possible, and the result was an incorrect result from the match.
2325    
2326        In order to prevent this happening, the specification of recursion has
2327        been changed so that all such subpatterns are automatically treated as
2328        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2329    
2330     4. I had overlooked the fact that, in some locales, there are characters for
2331        which isalpha() is true but neither isupper() nor islower() are true. In
2332        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2333        and ordfeminine) are like this. This affected the treatment of \w and \W
2334        when they appeared in character classes, but not when they appeared outside
2335        a character class. The bit map for "word" characters is now created
2336        separately from the results of isalnum() instead of just taking it from the
2337        upper, lower, and digit maps. (Plus the underscore character, of course.)
2338    
2339     5. The above bug also affected the handling of POSIX character classes such as
2340        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2341        permanent tables. Instead, the bit maps for such a class were previously
2342        created as the appropriate unions of the upper, lower, and digit bitmaps.
2343        Now they are created by subtraction from the [[:word:]] class, which has
2344        its own bitmap.
2345    
2346     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2347        It is created by subtracting the vertical space characters (\x09, \x0a,
2348        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2349        subtraction was done in the overall bitmap for a character class, meaning
2350        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2351        be recognized. This bug has been fixed.
2352    
2353     7. Patches from the folks at Google:
2354    
2355          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2356          real life, but is still worth protecting against".
2357    
2358          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2359          regular expressions".
2360    
2361          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2362          have it.
2363    
2364          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2365          "configure" and the latter not, in order to fix a problem somebody had
2366          with compiling the Arg class on HP-UX.
2367    
2368          (e) Improve the error-handling of the C++ wrapper a little bit.
2369    
2370          (f) New tests for checking recursion limiting.
2371    
2372     8. The pcre_memmove() function, which is used only if the environment does not
2373        have a standard memmove() function (and is therefore rarely compiled),
2374        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2375        returning a result (though PCRE never actually uses the result).
2376    
2377     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2378        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2379        returned instead of calling malloc() with an overflowing number that would
2380        most likely cause subsequent chaos.
2381    
2382    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2383    
2384    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2385        with this option is matched, the nmatch and pmatch options of regexec() are
2386        ignored.
2387    
2388    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2389        provided in case anyone wants to the the POSIX interface with UTF-8
2390        strings.
2391    
2392    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2393        C++ linking (needed for some HP-UX environments).
2394    
2395    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2396        (unused parameter) and in the pcre_printint() function (omitted "default"
2397        switch label when the default is to do nothing).
2398    
2399    15. Added some code to make it possible, when PCRE is compiled as a C++
2400        library, to replace subject pointers for pcre_exec() with a smart pointer
2401        class, thus making it possible to process discontinuous strings.
2402    
2403    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2404        much the same function. They were added by different people who were trying
2405        to make PCRE easy to compile on non-Unix systems. It has been suggested
2406        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2407        for compiling on Windows systems. I have therefore replaced it with
2408        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2409        defaults to "extern" for C or "extern C" for C++, which works fine on
2410        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2411        SCOPE with something explicit in config.h. In addition:
2412    
2413        (a) pcreposix.h still had just "extern" instead of either of these macros;
2414            I have replaced it with PCRE_DATA_SCOPE.
2415    
2416        (b) Functions such as _pcre_xclass(), which are internal to the library,
2417            but external in the C sense, all had PCRE_EXPORT in their definitions.
2418            This is apparently wrong for the Windows case, so I have removed it.
2419            (It makes no difference on Unix-like systems.)
2420    
2421    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2422        of recursive calls to match(). This is different to MATCH_LIMIT because
2423        that limits the total number of calls to match(), not all of which increase
2424        the depth of recursion. Limiting the recursion depth limits the amount of
2425        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2426        when PCRE is compiled, and changed at run time. A patch from Google adds
2427        this functionality to the C++ interface.
2428    
2429    18. Changes to the handling of Unicode character properties:
2430    
2431        (a) Updated the table to Unicode 4.1.0.
2432    
2433        (b) Recognize characters that are not in the table as "Cn" (undefined).
2434    
2435        (c) I revised the way the table is implemented to a much improved format
2436            which includes recognition of ranges. It now supports the ranges that
2437            are defined in UnicodeData.txt, and it also amalgamates other
2438            characters into ranges. This has reduced the number of entries in the
2439            table from around 16,000 to around 3,000, thus reducing its size
2440            considerably. I realized I did not need to use a tree structure after
2441            all - a binary chop search is just as efficient. Having reduced the
2442            number of entries, I extended their size from 6 bytes to 8 bytes to
2443            allow for more data.
2444    
2445        (d) Added support for Unicode script names via properties such as \p{Han}.
2446    
2447    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2448        matching that character.
2449    
2450    20. When matching a repeated Unicode property with a minimum greater than zero,
2451        (for example \pL{2,}), PCRE could look past the end of the subject if it
2452        reached it while seeking the minimum number of characters. This could
2453        happen only if some of the characters were more than one byte long, because
2454        there is a check for at least the minimum number of bytes.
2455    
2456    21. Refactored the implementation of \p and \P so as to be more general, to
2457        allow for more different types of property in future. This has changed the
2458        compiled form incompatibly. Anybody with saved compiled patterns that use
2459        \p or \P will have to recompile them.
2460    
2461    22. Added "Any" and "L&" to the supported property types.
2462    
2463    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2464        but give a compile time error if the value is greater than 0xff.
2465    
2466    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2467        accidentally not being installed or uninstalled.
2468    
2469    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2470        made were to insert the current release number. This seemed silly, because
2471        it made things harder for people building PCRE on systems that don't run
2472        "configure". I have turned pcre.h into a distributed file, no longer built
2473        by "configure", with the version identification directly included. There is
2474        no longer a pcre.h.in file.
2475    
2476        However, this change necessitated a change to the pcre-config script as
2477        well. It is built from pcre-config.in, and one of the substitutions was the
2478        release number. I have updated configure.ac so that ./configure now finds
2479        the release number by grepping pcre.h.
2480    
2481    26. Added the ability to run the tests under valgrind.
2482    
2483    
2484    Version 6.4 05-Sep-05
2485    ---------------------
2486    
2487     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2488        "--" to be printed when multiple files were scanned, even when none of the
2489        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2490        consider it to be a bug, and have restored the previous behaviour.
2491    
2492     2. A couple of code tidies to get rid of compiler warnings.
2493    
2494     3. The pcretest program used to cheat by referring to symbols in the library
2495        whose names begin with _pcre_. These are internal symbols that are not
2496        really supposed to be visible externally, and in some environments it is
2497        possible to suppress them. The cheating is now confined to including
2498        certain files from the library's source, which is a bit cleaner.
2499    
2500     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2501        file's purpose clearer.
2502    
2503     5. Reorganized pcre_ucp_findchar().
2504    
2505    
2506    Version 6.3 15-Aug-05
2507    ---------------------
2508    
2509     1. The file libpcre.pc.in did not have general read permission in the tarball.
2510    
2511     2. There were some problems when building without C++ support:
2512    
2513        (a) If C++ support was not built, "make install" and "make test" still
2514            tried to test it.
2515    
2516        (b) There were problems when the value of CXX was explicitly set. Some
2517            changes have been made to try to fix these, and ...
2518    
2519        (c) --disable-cpp can now be used to explicitly disable C++ support.
2520    
2521        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2522            backslash in a target when C++ was disabled. This confuses some
2523            versions of "make", apparently. Using an intermediate variable solves
2524            this. (Same for CPP_LOBJ.)
2525    
2526     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2527        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2528        necessary on certain architectures.
2529    
2530     4. Added a setting of -export-symbols-regex to the link command to remove
2531        those symbols that are exported in the C sense, but actually are local
2532        within the library, and not documented. Their names all begin with
2533        "_pcre_". This is not a perfect job, because (a) we have to except some
2534        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2535        available (and never for static libraries). I have made a note to try to
2536        find a way round (a) in the future.
2537    
2538    
2539    Version 6.2 01-Aug-05
2540    ---------------------
2541    
2542     1. There was no test for integer overflow of quantifier values. A construction
2543        such as {1111111111111111} would give undefined results. What is worse, if
2544        a minimum quantifier for a parenthesized subpattern overflowed and became
2545        negative, the calculation of the memory size went wrong. This could have
2546        led to memory overwriting.
2547    
2548     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2549    
2550     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2551        operating environments where this matters.
2552    
2553     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2554        PCRE options from within the C++ wrapper.
2555    
2556     5. Named capturing subpatterns were not being correctly counted when a pattern
2557        was compiled. This caused two problems: (a) If there were more than 100
2558        such subpatterns, the calculation of the memory needed for the whole
2559        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2560        back references of the form \12, where the number was greater than 9, were
2561        not recognized as back references, even though there were sufficient
2562        previous subpatterns.
2563    
2564     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2565        versions of gcc, e.g. 2.95.4.
2566    
2567    
2568    Version 6.1 21-Jun-05
2569    ---------------------
2570    
2571     1. There was one reference to the variable "posix" in pcretest.c that was not
2572        surrounded by "#if !defined NOPOSIX".
2573    
2574     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2575        the cross-check on the old pcre_info() function, for the benefit of the
2576        cut-down version of PCRE that is currently imported into Exim.
2577    
2578     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2579        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2580        patterns that start (?i) but I don't think that matters. The use of (?i) is
2581        just an example; this all applies to the other options as well.
2582    
2583     4. Since libtool seems to echo the compile commands it is issuing, the output
2584        from "make" can be reduced a bit by putting "@" in front of each libtool
2585        compile command.
2586    
2587     5. Patch from the folks at Google for configure.in to be a bit more thorough
2588        in checking for a suitable C++ installation before trying to compile the
2589        C++ stuff. This should fix a reported problem when a compiler was present,
2590        but no suitable headers.
2591    
2592     6. The man pages all had just "PCRE" as their title. I have changed them to
2593        be the relevant file name. I have also arranged that these names are
2594        retained in the file doc/pcre.txt, which is a concatenation in text format
2595        of all the man pages except the little individual ones for each function.
2596    
2597     7. The NON-UNIX-USE file had not been updated for the different set of source
2598        files that come with release 6. I also added a few comments about the C++
2599        wrapper.
2600    
2601    
2602    Version 6.0 07-Jun-05
2603    ---------------------
2604    
2605     1. Some minor internal re-organization to help with my DFA experiments.
2606    
2607     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2608        didn't matter for the library itself when fully configured, but did matter
2609        when compiling without UCP support, or within Exim, where the ucp files are
2610        not imported.
2611    
2612     3. Refactoring of the library code to split up the various functions into
2613        different source modules. The addition of the new DFA matching code (see
2614        below) to a single monolithic source would have made it really too
2615        unwieldy, quite apart from causing all the code to be include in a
2616        statically linked application, when only some functions are used. This is
2617        relevant even without the DFA addition now that patterns can be compiled in
2618        one application and matched in another.
2619    
2620        The downside of splitting up is that there have to be some external
2621        functions and data tables that are used internally in different modules of
2622        the library but which are not part of the API. These have all had their
2623        names changed to start with "_pcre_" so that they are unlikely to clash
2624        with other external names.
2625    
2626     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2627        a different (DFA) algorithm. Although it is slower than the original
2628        function, it does have some advantages for certain types of matching
2629        problem.
2630    
2631     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2632        including restarting after a partial match.
2633    
2634     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2635        defined when compiling for Windows was sent to me. I have put it into the
2636        code, though I have no means of testing or verifying it.
2637    
2638     7. Added the pcre_refcount() auxiliary function.
2639    
2640     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2641        match before or at the first newline in the subject string. In pcretest,
2642        the /f option on a pattern can be used to set this.
2643    
2644     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2645        would behave wrongly. This has been present in PCRE since release 4.0.
2646    
2647    10. A number of changes to the pcregrep command:
2648    
2649        (a) Refactored how -x works; insert ^(...)$ instead of setting
2650            PCRE_ANCHORED and checking the length, in preparation for adding
2651            something similar for -w.
2652    
2653        (b) Added the -w (match as a word) option.
2654    
2655        (c) Refactored the way lines are read and buffered so as to have more
2656            than one at a time available.
2657    
2658        (d) Implemented a pcregrep test script.
2659    
2660        (e) Added the -M (multiline match) option. This allows patterns to match
2661            over several lines of the subject. The buffering ensures that at least
2662            8K, or the rest of the document (whichever is the shorter) is available
2663            for matching (and similarly the previous 8K for lookbehind assertions).
2664    
2665        (f) Changed the --help output so that it now says
2666    
2667              -w, --word-regex(p)
2668    
2669            instead of two lines, one with "regex" and the other with "regexp"
2670            because that confused at least one person since the short forms are the
2671            same. (This required a bit of code, as the output is generated
2672            automatically from a table. It wasn't just a text change.)
2673    
2674        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2675            option but starts with a hyphen. Could be a pattern or a path name
2676            starting with a hyphen, for instance.
2677    
2678        (h) "-" can be given as a file name to represent stdin.
2679    
2680        (i) When file names are being printed, "(standard input)" is used for
2681            the standard input, for compatibility with GNU grep. Previously
2682            "<stdin>" was used.
2683    
2684        (j) The option --label=xxx can be used to supply a name to be used for
2685            stdin when file names are being printed. There is no short form.
2686    
2687        (k) Re-factored the options decoding logic because we are going to add
2688            two more options that take data. Such options can now be given in four
2689            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2690    
2691        (l) Added the -A, -B, and -C options for requesting that lines of context
2692            around matches be printed.
2693    
2694        (m) Added the -L option to print the names of files that do not contain
2695            any matching lines, that is, the complement of -l.
2696    
2697        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2698            continue to scan other files.
2699    
2700        (o) The -s option was incorrectly implemented. For compatibility with other
2701            greps, it now suppresses the error message for a non-existent or non-
2702            accessible file (but not the return code). There is a new option called
2703            -q that suppresses the output of matching lines, which was what -s was
2704            previously doing.
2705    
2706        (p) Added --include and --exclude options to specify files for inclusion
2707            and exclusion when recursing.
2708    
2709    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2710        Hopefully, it now does.
2711    
2712    12. Missing cast in pcre_study().
2713    
2714    13. Added an "uninstall" target to the makefile.
2715    
2716    14. Replaced "extern" in the function prototypes in Makefile.in with
2717        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2718        world, but is set differently for Windows.
2719    
2720    15. Added a second compiling function called pcre_compile2(). The only
2721        difference is that it has an extra argument, which is a pointer to an
2722        integer error code. When there is a compile-time failure, this is set
2723        non-zero, in addition to the error test pointer being set to point to an
2724        error message. The new argument may be NULL if no error number is required
2725        (but then you may as well call pcre_compile(), which is now just a
2726        wrapper). This facility is provided because some applications need a
2727        numeric error indication, but it has also enabled me to tidy up the way
2728        compile-time errors are handled in the POSIX wrapper.
2729    
2730    16. Added VPATH=.libs to the makefile; this should help when building with one
2731        prefix path and installing with another. (Or so I'm told by someone who
2732        knows more about this stuff than I do.)
2733    
2734    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2735        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2736        match everything, including newlines. This is not POSIX-compatible, but
2737        somebody wanted the feature. From pcretest it can be activated by using
2738        both the P and the s flags.
2739    
2740    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2741    
2742    19. libpcre.pc was being incorrectly installed as executable.
2743    
2744    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2745        it now also looks for '\r' so that it will work unmodified on Windows.
2746    
2747    21. Added Google's contributed C++ wrapper to the distribution.
2748    
2749    22. Added some untidy missing memory free() calls in pcretest, to keep
2750        Electric Fence happy when testing.
2751    
2752    
2753    
2754    Version 5.0 13-Sep-04
2755    ---------------------
2756    
2757     1. Internal change: literal characters are no longer packed up into items
2758        containing multiple characters in a single byte-string. Each character
2759        is now matched using a separate opcode. However, there may be more than one
2760        byte in the character in UTF-8 mode.
2761    
2762     2. The pcre_callout_block structure has two new fields: pattern_position and
2763        next_item_length. These contain the offset in the pattern to the next match
2764        item, and its length, respectively.
2765    
2766     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2767        insertion of callouts before each pattern item. Added the /C option to
2768        pcretest to make use of this.
2769    
2770     4. On the advice of a Windows user, the lines
2771    
2772          #if defined(_WIN32) || defined(WIN32)
2773          _setmode( _fileno( stdout ), 0x8000 );
2774          #endif  /* defined(_WIN32) || defined(WIN32) */
2775    
2776        have been added to the source of pcretest. This apparently does useful
2777        magic in relation to line terminators.
2778    
2779     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2780        for the benefit of those environments where the "b" makes a difference.
2781    
2782     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2783        to know about it. I have put a hack into configure.in that adds in code
2784        to set GCC=yes if CC=icc. This seems to end up at a point in the
2785        generated configure script that is early enough to affect the setting of
2786        compiler options, which is what is needed, but I have no means of testing
2787        whether it really works. (The user who reported this had patched the
2788        generated configure script, which of course I cannot do.)
2789    
2790        LATER: After change 22 below (new libtool files), the configure script
2791        seems to know about icc (and also ecc). Therefore, I have commented out
2792        this hack in configure.in.
2793    
2794     7. Added support for pkg-config (2 patches were sent in).
2795    
2796     8. Negated POSIX character classes that used a combination of internal tables
2797        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2798        [[:^ascii]]. Typically, they would match almost any characters. The other
2799        POSIX classes were not broken in this way.
2800    
2801     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2802        to find the match, as PCRE was deluded into thinking that the match had to
2803        start at the start point or following a newline. The same bug applied to
2804        patterns with negative forward assertions or any backward assertions
2805        preceding ".*" at the start, unless the pattern required a fixed first
2806        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2807    
2808    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2809        starting at the last subject character, bytes beyond the end of the subject
2810        string were read.
2811    
2812    11. Renamed the variable "class" as "classbits" to make life easier for C++
2813        users. (Previously there was a macro definition, but it apparently wasn't
2814        enough.)
2815    
2816    12. Added the new field "tables" to the extra data so that tables can be passed
2817        in at exec time, or the internal tables can be re-selected. This allows
2818        a compiled regex to be saved and re-used at a later time by a different
2819        program that might have everything at different addresses.
2820    
2821    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2822        -R library as well as a -L library.
2823    
2824    14. The debugging options of pcretest (-d on the command line or D on a
2825        pattern) showed incorrect output for anything following an extended class
2826        that contained multibyte characters and which was followed by a quantifier.
2827    
2828    15. Added optional support for general category Unicode character properties
2829        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2830        support. It adds about 90K to the size of the library. The meanings of the
2831        inbuilt class escapes such as \d and \s have NOT been changed.
2832    
2833    16. Updated pcredemo.c to include calls to free() to release the memory for the
2834        compiled pattern.
2835    
2836    17. The generated file chartables.c was being created in the source directory
2837        instead of in the building directory. This caused the build to fail if the
2838        source directory was different from the building directory, and was
2839        read-only.
2840    
2841    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2842        file. No doubt somebody will tell me if they don't make sense... Also added
2843        Dan Mooney's comments about building on OpenVMS.
2844    
2845    19. Added support for partial matching via the PCRE_PARTIAL option for
2846        pcre_exec() and the \P data escape in pcretest.
2847    
2848    20. Extended pcretest with 3 new pattern features:
2849    
2850        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2851              write the compiled pattern to the file whose name is "rest-of-line".
2852              This is a straight binary dump of the data, with the saved pointer to
2853              the character tables forced to be NULL. The study data, if any, is
2854              written too. After writing, pcretest reads a new pattern.
2855    
2856        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2857              compiled pattern from the given file. There must not be any
2858              occurrences of "<" in the file name (pretty unlikely); if there are,
2859              pcretest will instead treat the initial "<" as a pattern delimiter.
2860              After reading in the pattern, pcretest goes on to read data lines as
2861              usual.
2862    
2863        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2864              and 16-bit fields in a compiled pattern, to simulate a pattern that
2865              was compiled on a host of opposite endianness.
2866    
2867    21. The pcre-exec() function can now cope with patterns that were compiled on
2868        hosts of opposite endianness, with this restriction:
2869    
2870          As for any compiled expression that is saved and used later, the tables
2871          pointer field cannot be preserved; the extra_data field in the arguments
2872          to pcre_exec() should be used to pass in a tables address if a value
2873          other than the default internal tables were used at compile time.
2874    
2875    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2876        now diagnosed as an error. Previously, most of the time, a negative number
2877        would have been treated as zero, but if in addition "ovector" was passed as
2878        NULL, a crash could occur.
2879    
2880    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2881        new versions from the libtool 1.5 distribution (the last one is a copy of
2882        a file called libtool.m4). This seems to have fixed the need to patch
2883        "configure" to support Darwin 1.3 (which I used to do). However, I still
2884        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2885        workstation).
2886    
2887    24. Changed the PCRE licence to be the more standard "BSD" licence.
2888    
2889    
2890  Version 4.5 01-Dec-03  Version 4.5 01-Dec-03
2891  ---------------------  ---------------------
2892    

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