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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.7 05-Mar-08  Version 8.21
5    ------------
6    
7    1.  Updating the JIT compiler.
8    
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
11    
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
15    
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
19    
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
22    
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
26    
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
36    
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
39    
40    
41    Version 8.20 21-Oct-2011
42    ------------------------
43    
44    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
45        a POSIX class. After further experiments with Perl, which convinced me that
46        Perl has bugs and confusions, a closing square bracket is no longer allowed
47        in a POSIX name. This bug also affected patterns with classes that started
48        with full stops.
49    
50    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
51        captured substring, but while checking the failing first alternative,
52        substring 1 is temporarily captured. If the output vector supplied to
53        pcre_exec() was not big enough for this capture, the yield of the function
54        was still zero ("insufficient space for captured substrings"). This cannot
55        be totally fixed without adding another stack variable, which seems a lot
56        of expense for a edge case. However, I have improved the situation in cases
57        such as /(a)(b)x|abc/ matched against "abc", where the return code
58        indicates that fewer than the maximum number of slots in the ovector have
59        been set.
60    
61    3.  Related to (2) above: when there are more back references in a pattern than
62        slots in the output vector, pcre_exec() uses temporary memory during
63        matching, and copies in the captures as far as possible afterwards. It was
64        using the entire output vector, but this conflicts with the specification
65        that only 2/3 is used for passing back captured substrings. Now it uses
66        only the first 2/3, for compatibility. This is, of course, another edge
67        case.
68    
69    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
70        main code base, and can be used by building with --enable-jit. When this is
71        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
72        runtime --no-jit option is given.
73    
74    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
75        ovector, the return from the function was zero, implying that there were
76        other matches that did not fit. The correct "exactly full" value is now
77        returned.
78    
79    6.  If a subpattern that was called recursively or as a subroutine contained
80        (*PRUNE) or any other control that caused it to give a non-standard return,
81        invalid errors such as "Error -26 (nested recursion at the same subject
82        position)" or even infinite loops could occur.
83    
84    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
85        computing the minimum length on reaching *ACCEPT, and so ended up with the
86        wrong value of 1 rather than 0. Further investigation indicates that
87        computing a minimum subject length in the presence of *ACCEPT is difficult
88        (think back references, subroutine calls), and so I have changed the code
89        so that no minimum is registered for a pattern that contains *ACCEPT.
90    
91    8.  If (*THEN) was present in the first (true) branch of a conditional group,
92        it was not handled as intended. [But see 16 below.]
93    
94    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
95        Sheri Pierce.
96    
97    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
98        the first byte in a match must be "a".
99    
100    11. Change 17 for 8.13 increased the recursion depth for patterns like
101        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
102        pattern contains any instances of (*THEN). If it does not, the old
103        optimizations are restored. It would be nice to do this on a per-group
104        basis, but at the moment that is not feasible.
105    
106    12. In some environments, the output of pcretest -C is CRLF terminated. This
107        broke RunTest's code that checks for the link size. A single white space
108        character after the value is now allowed for.
109    
110    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
111        For "fr", it uses the Windows-specific input and output files.
112    
113    14. If (*THEN) appeared in a group that was called recursively or as a
114        subroutine, it did not work as intended. [But see next item.]
115    
116    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
117        pattern fragments (but not containing any | characters). If A and B are
118        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
119        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
120        D. In other words, Perl considers parentheses that do not contain any |
121        characters to be part of a surrounding alternative, whereas PCRE was
122        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
123        differently. PCRE now behaves in the same way as Perl, except in the case
124        of subroutine/recursion calls such as (?1) which have in any case always
125        been different (but PCRE had them first :-).
126    
127    16. Related to 15 above: Perl does not treat the | in a conditional group as
128        creating alternatives. Such a group is treated in the same way as an
129        ordinary group without any | characters when processing (*THEN). PCRE has
130        been changed to match Perl's behaviour.
131    
132    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
133        RunGrepTest script failed.
134    
135    18. Change 22 for version 13 caused atomic groups to use more stack. This is
136        inevitable for groups that contain captures, but it can lead to a lot of
137        stack use in large patterns. The old behaviour has been restored for atomic
138        groups that do not contain any capturing parentheses.
139    
140    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
141        suppress the check for a minimum subject length at run time. (If it was
142        given to pcre_exec() or pcre_dfa_exec() it did work.)
143    
144    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
145        fail to work when decoding hex characters in data strings in EBCDIC
146        environments.
147    
148    21. It appears that in at least one Mac OS environment, the isxdigit() function
149        is implemented as a macro that evaluates to its argument more than once,
150        contravening the C 90 Standard (I haven't checked a later standard). There
151        was an instance in pcretest which caused it to go wrong when processing
152        \x{...} escapes in subject strings. The has been rewritten to avoid using
153        things like p++ in the argument of isxdigit().
154    
155    
156    Version 8.13 16-Aug-2011
157    ------------------------
158    
159    1.  The Unicode data tables have been updated to Unicode 6.0.0.
160    
161    2.  Two minor typos in pcre_internal.h have been fixed.
162    
163    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
164        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
165        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
166    
167    4.  There were a number of related bugs in the code for matching backrefences
168        caselessly in UTF-8 mode when codes for the characters concerned were
169        different numbers of bytes. For example, U+023A and U+2C65 are an upper
170        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
171        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
172        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
173        2-byte code at the end of the subject (it thought there wasn't enough data
174        left).
175    
176    5.  Comprehensive information about what went wrong is now returned by
177        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
178        as the output vector has at least 2 elements. The offset of the start of
179        the failing character and a reason code are placed in the vector.
180    
181    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
182        now returned is for the first byte of the failing character, instead of the
183        last byte inspected. This is an incompatible change, but I hope it is small
184        enough not to be a problem. It makes the returned offset consistent with
185        pcre_exec() and pcre_dfa_exec().
186    
187    7.  pcretest now gives a text phrase as well as the error number when
188        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
189        failure, the offset and reason code are output.
190    
191    8.  When \R was used with a maximizing quantifier it failed to skip backwards
192        over a \r\n pair if the subsequent match failed. Instead, it just skipped
193        back over a single character (\n). This seems wrong (because it treated the
194        two characters as a single entity when going forwards), conflicts with the
195        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
196        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
197        has been changed.
198    
199    9.  Some internal refactoring has changed the processing so that the handling
200        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
201        time (the PCRE_DOTALL option was changed this way some time ago: version
202        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
203        which was always a bit of a fudge. It also means that there is one less
204        argument for the match() function, which reduces its stack requirements
205        slightly. This change also fixes an incompatibility with Perl: the pattern
206        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
207    
208    10. More internal refactoring has drastically reduced the number of recursive
209        calls to match() for possessively repeated groups such as (abc)++ when
210        using pcre_exec().
211    
212    11. While implementing 10, a number of bugs in the handling of groups were
213        discovered and fixed:
214    
215        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
216        (a|)*(?1) gave a compile-time internal error.
217        ((a|)+)+  did not notice that the outer group could match an empty string.
218        (^a|^)+   was not marked as anchored.
219        (.*a|.*)+ was not marked as matching at start or after a newline.
220    
221    12. Yet more internal refactoring has removed another argument from the match()
222        function. Special calls to this function are now indicated by setting a
223        value in a variable in the "match data" data block.
224    
225    13. Be more explicit in pcre_study() instead of relying on "default" for
226        opcodes that mean there is no starting character; this means that when new
227        ones are added and accidentally left out of pcre_study(), testing should
228        pick them up.
229    
230    14. The -s option of pcretest has been documented for ages as being an old
231        synonym of -m (show memory usage). I have changed it to mean "force study
232        for every regex", that is, assume /S for every regex. This is similar to -i
233        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
234        using it. It makes it easier to run collections of tests with and without
235        study enabled, and thereby test pcre_study() more easily. All the standard
236        tests are now run with and without -s (but some patterns can be marked as
237        "never study" - see 20 below).
238    
239    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
240        restoration of the capturing data to the outer values was not happening
241        correctly.
242    
243    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
244        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
245        pattern had matched an empty string, and so incorrectly returned a no
246        match.
247    
248    17. There was optimizing code for the last branch of non-capturing parentheses,
249        and also for the obeyed branch of a conditional subexpression, which used
250        tail recursion to cut down on stack usage. Unfortunately, now that there is
251        the possibility of (*THEN) occurring in these branches, tail recursion is
252        no longer possible because the return has to be checked for (*THEN). These
253        two optimizations have therefore been removed. [But see 8.20/11 above.]
254    
255    18. If a pattern containing \R was studied, it was assumed that \R always
256        matched two bytes, thus causing the minimum subject length to be
257        incorrectly computed because \R can also match just one byte.
258    
259    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
260        was incorrectly computed.
261    
262    20. If /S is present twice on a test pattern in pcretest input, it now
263        *disables* studying, thereby overriding the use of -s on the command line
264        (see 14 above). This is necessary for one or two tests to keep the output
265        identical in both cases.
266    
267    21. When (*ACCEPT) was used in an assertion that matched an empty string and
268        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
269    
270    22. When an atomic group that contained a capturing parenthesis was
271        successfully matched, but the branch in which it appeared failed, the
272        capturing was not being forgotten if a higher numbered group was later
273        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
274        group 1 to "a", when in fact it should be unset. This applied to multi-
275        branched capturing and non-capturing groups, repeated or not, and also to
276        positive assertions (capturing in negative assertions does not happen
277        in PCRE) and also to nested atomic groups.
278    
279    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
280        subject after a captured substring, to make it easier to tell which of a
281        number of identical substrings has been captured.
282    
283    24. The way atomic groups are processed by pcre_exec() has been changed so that
284        if they are repeated, backtracking one repetition now resets captured
285        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
286        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
287        "aaa". Previously, it would have been "a". As part of this code
288        refactoring, the way recursive calls are handled has also been changed.
289    
290    25. If an assertion condition captured any substrings, they were not passed
291        back unless some other capturing happened later. For example, if
292        (?(?=(a))a) was matched against "a", no capturing was returned.
293    
294    26. When studying a pattern that contained subroutine calls or assertions,
295        the code for finding the minimum length of a possible match was handling
296        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
297        group 1 called group 2 while simultaneously a separate group 2 called group
298        1). A stack overflow occurred in this case. I have fixed this by limiting
299        the recursion depth to 10.
300    
301    27. Updated RunTest.bat in the distribution to the version supplied by Tom
302        Fortmann. This supports explicit test numbers on the command line, and has
303        argument validation and error reporting.
304    
305    28. An instance of \X with an unlimited repeat could fail if at any point the
306        first character it looked at was a mark character.
307    
308    29. Some minor code refactoring concerning Unicode properties and scripts
309        should reduce the stack requirement of match() slightly.
310    
311    30. Added the '=' option to pcretest to check the setting of unused capturing
312        slots at the end of the pattern, which are documented as being -1, but are
313        not included in the return count.
314    
315    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
316        compiled something random. Now it gives a compile-time error (as does
317        Perl).
318    
319    32. A *MARK encountered during the processing of a positive assertion is now
320        recorded and passed back (compatible with Perl).
321    
322    33. If --only-matching or --colour was set on a pcregrep call whose pattern
323        had alternative anchored branches, the search for a second match in a line
324        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
325        matched the line "0102" twice. The same bug affected patterns that started
326        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
327        twice.
328    
329    34. Previously, PCRE did not allow quantification of assertions. However, Perl
330        does, and because of capturing effects, quantifying parenthesized
331        assertions may at times be useful. Quantifiers are now allowed for
332        parenthesized assertions.
333    
334    35. A minor code tidy in pcre_compile() when checking options for \R usage.
335    
336    36. \g was being checked for fancy things in a character class, when it should
337        just be a literal "g".
338    
339    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
340        appearance of a nested POSIX class supersedes an apparent external class.
341        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
342        unescaped square brackets may also appear as part of class names. For
343        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
344        more like Perl. (But see 8.20/1 above.)
345    
346    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
347        was because it thought it was \N{name}, which is not supported).
348    
349    39. Add minix to OS list not supporting the -S option in pcretest.
350    
351    40. PCRE tries to detect cases of infinite recursion at compile time, but it
352        cannot analyze patterns in sufficient detail to catch mutual recursions
353        such as ((?1))((?2)). There is now a runtime test that gives an error if a
354        subgroup is called recursively as a subpattern for a second time at the
355        same position in the subject string. In previous releases this might have
356        been caught by the recursion limit, or it might have run out of stack.
357    
358    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
359        happen only once. PCRE was, however incorrectly giving a compile time error
360        "recursive call could loop indefinitely" because it cannot analyze the
361        pattern in sufficient detail. The compile time test no longer happens when
362        PCRE is compiling a conditional subpattern, but actual runaway loops are
363        now caught at runtime (see 40 above).
364    
365    42. It seems that Perl allows any characters other than a closing parenthesis
366        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
367        has been changed to be the same.
368    
369    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
370        as not to get warnings when autogen.sh is called. Also changed
371        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
372    
373    44. To help people who use pcregrep to scan files containing exceedingly long
374        lines, the following changes have been made:
375    
376        (a) The default value of the buffer size parameter has been increased from
377            8K to 20K. (The actual buffer used is three times this size.)
378    
379        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
380            PCRE is built.
381    
382        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
383            to be set at run time.
384    
385        (d) Numerical values in pcregrep options can be followed by K or M, for
386            example --buffer-size=50K.
387    
388        (e) If a line being scanned overflows pcregrep's buffer, an error is now
389            given and the return code is set to 2.
390    
391    45. Add a pointer to the latest mark to the callout data block.
392    
393    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
394        partial match of an empty string instead of no match. This was specific to
395        the use of ".".
396    
397    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
398        complete match instead of a partial match. This bug was dependent on both
399        the PCRE_UTF8 and PCRE_DOTALL options being set.
400    
401    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
402        starting byte set, because \b was not being ignored.
403    
404    
405    Version 8.12 15-Jan-2011
406    ------------------------
407    
408    1.  Fixed some typos in the markup of the man pages, and wrote a script that
409        checks for such things as part of the documentation building process.
410    
411    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
412        --match-limit and --recursion-limit options (added for 8.11). In
413        particular, this made one of the standard tests fail. (The integer value
414        went into the wrong half of a long int.)
415    
416    3.  If the --colour option was given to pcregrep with -v (invert match), it
417        did strange things, either producing crazy output, or crashing. It should,
418        of course, ignore a request for colour when reporting lines that do not
419        match.
420    
421    4.  Another pcregrep bug caused similar problems if --colour was specified with
422        -M (multiline) and the pattern match finished with a line ending.
423    
424    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
425        matched in multiline mode, the following line was shown as part of the
426        match. This seems wrong, so I have changed it.
427    
428    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
429        the check for further matches in the same line (so they could be coloured)
430        to overrun the end of the current line. If another match was found, it was
431        incorrectly shown (and then shown again when found in the next line).
432    
433    7.  If pcregrep was compiled under Windows, there was a reference to the
434        function pcregrep_exit() before it was defined. I am assuming this was
435        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
436        reported by a user. I've moved the definition above the reference.
437    
438    
439    Version 8.11 10-Dec-2010
440    ------------------------
441    
442    1.  (*THEN) was not working properly if there were untried alternatives prior
443        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
444        backtracked to try for "b" instead of moving to the next alternative branch
445        at the same level (in this case, to look for "c"). The Perl documentation
446        is clear that when (*THEN) is backtracked onto, it goes to the "next
447        alternative in the innermost enclosing group".
448    
449    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
450        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
451        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
452        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
453        (*THEN).
454    
455    3.  If \s appeared in a character class, it removed the VT character from
456        the class, even if it had been included by some previous item, for example
457        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
458        of \s, but is part of the POSIX "space" class.)
459    
460    4.  A partial match never returns an empty string (because you can always
461        match an empty string at the end of the subject); however the checking for
462        an empty string was starting at the "start of match" point. This has been
463        changed to the "earliest inspected character" point, because the returned
464        data for a partial match starts at this character. This means that, for
465        example, /(?<=abc)def/ gives a partial match for the subject "abc"
466        (previously it gave "no match").
467    
468    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
469        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
470        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
471        has an implication that the given string is incomplete (because a partial
472        match is preferred over a full match). For this reason, these items now
473        give a partial match in this situation. [Aside: previously, the one case
474        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
475        match rather than a full match, which was wrong by the old rules, but is
476        now correct.]
477    
478    6.  There was a bug in the handling of #-introduced comments, recognized when
479        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
480        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
481        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
482        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
483        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
484        places in pcre_compile().
485    
486    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
487        comments when looking ahead for named forward references to subpatterns,
488        the only newline sequence it recognized was NL. It now handles newlines
489        according to the set newline convention.
490    
491    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
492        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
493        cater for a lack of strerror(). These oversights have been fixed.
494    
495    9.  Added --match-limit and --recursion-limit to pcregrep.
496    
497    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
498    
499    11. When the -o option was used, pcregrep was setting a return code of 1, even
500        when matches were found, and --line-buffered was not being honoured.
501    
502    12. Added an optional parentheses number to the -o and --only-matching options
503        of pcregrep.
504    
505    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
506        can match an empty string. The code to do it in pcretest and pcredemo
507        needed fixing:
508    
509        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
510            only one byte after an empty string match just before CRLF (this case
511            just got forgotten; "any" and "anycrlf" were OK).
512    
513        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
514            mode when an empty string match preceded an ASCII character followed by
515            a non-ASCII character. (The code for advancing by one character rather
516            than one byte was nonsense.)
517    
518        (c) The pcredemo.c sample program did not have any code at all to handle
519            the cases when CRLF is a valid newline sequence.
520    
521    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
522        as a starting offset was within the subject string. There is now a new
523        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
524        negative or greater than the length of the string. In order to test this,
525        pcretest is extended to allow the setting of negative starting offsets.
526    
527    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
528        starting offset points to the beginning of a UTF-8 character was
529        unnecessarily clumsy. I tidied it up.
530    
531    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
532        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
533    
534    17. Nobody had reported that the --include_dir option, which was added in
535        release 7.7 should have been called --include-dir (hyphen, not underscore)
536        for compatibility with GNU grep. I have changed it to --include-dir, but
537        left --include_dir as an undocumented synonym, and the same for
538        --exclude-dir, though that is not available in GNU grep, at least as of
539        release 2.5.4.
540    
541    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
542        characters from a string of bytes) have been redefined so as not to use
543        loops, in order to improve performance in some environments. At the same
544        time, I abstracted some of the common code into auxiliary macros to save
545        repetition (this should not affect the compiled code).
546    
547    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
548        compile-time error is now given if \c is not followed by an ASCII
549        character, that is, a byte less than 128. (In EBCDIC mode, the code is
550        different, and any byte value is allowed.)
551    
552    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
553        START_OPTIMIZE option, which is now allowed at compile time - but just
554        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
555        to pcregrep and other applications that have no direct access to PCRE
556        options. The new /Y option in pcretest sets this option when calling
557        pcre_compile().
558    
559    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
560        back references. Groups containing recursive back references were forced to
561        be atomic by that change, but in the case of named groups, the amount of
562        memory required was incorrectly computed, leading to "Failed: internal
563        error: code overflow". This has been fixed.
564    
565    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
566        pcretest.c, to avoid build problems in some Borland environments.
567    
568    
569    Version 8.10 25-Jun-2010
570    ------------------------
571    
572    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
573        THEN.
574    
575    2.  (*ACCEPT) was not working when inside an atomic group.
576    
577    3.  Inside a character class, \B is treated as a literal by default, but
578        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
579        causes the error). The code is unchanged, but I tidied the documentation.
580    
581    4.  Inside a character class, PCRE always treated \R and \X as literals,
582        whereas Perl faults them if its -w option is set. I have changed PCRE so
583        that it faults them when PCRE_EXTRA is set.
584    
585    5.  Added support for \N, which always matches any character other than
586        newline. (It is the same as "." when PCRE_DOTALL is not set.)
587    
588    6.  When compiling pcregrep with newer versions of gcc which may have
589        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
590        declared with attribute warn_unused_result" were given. Just casting the
591        result to (void) does not stop the warnings; a more elaborate fudge is
592        needed. I've used a macro to implement this.
593    
594    7.  Minor change to pcretest.c to avoid a compiler warning.
595    
596    8.  Added four artifical Unicode properties to help with an option to make
597        \s etc use properties (see next item). The new properties are: Xan
598        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
599    
600    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
601        use Unicode properties. (*UCP) at the start of a pattern can be used to set
602        this option. Modified pcretest to add /W to test this facility. Added
603        REG_UCP to make it available via the POSIX interface.
604    
605    10. Added --line-buffered to pcregrep.
606    
607    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
608        studied, and the match started with a letter with a code point greater than
609        127 whose first byte was different to the first byte of the other case of
610        the letter, the other case of this starting letter was not recognized
611        (#976).
612    
613    12. If a pattern that was studied started with a repeated Unicode property
614        test, for example, \p{Nd}+, there was the theoretical possibility of
615        setting up an incorrect bitmap of starting bytes, but fortunately it could
616        not have actually happened in practice until change 8 above was made (it
617        added property types that matched character-matching opcodes).
618    
619    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
620        possible starting bytes for non-anchored patterns.
621    
622    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
623        \R, and also a number of cases that involve Unicode properties, both
624        explicit and implicit when PCRE_UCP is set.
625    
626    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
627        input, it could crash or give wrong results if characters with values
628        greater than 0xc0 were present in the subject string. (Detail: it assumed
629        UTF-8 input when processing these items.)
630    
631    16. Added a lot of (int) casts to avoid compiler warnings in systems where
632        size_t is 64-bit (#991).
633    
634    17. Added a check for running out of memory when PCRE is compiled with
635        --disable-stack-for-recursion (#990).
636    
637    18. If the last data line in a file for pcretest does not have a newline on
638        the end, a newline was missing in the output.
639    
640    19. The default pcre_chartables.c file recognizes only ASCII characters (values
641        less than 128) in its various bitmaps. However, there is a facility for
642        generating tables according to the current locale when PCRE is compiled. It
643        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
644        characters, are recognized by isspace() and therefore were getting set in
645        these tables, and indeed these tables seem to approximate to ISO 8859. This
646        caused a problem in UTF-8 mode when pcre_study() was used to create a list
647        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
648        which of course cannot start UTF-8 characters. I have changed the code so
649        that only real ASCII characters (less than 128) and the correct starting
650        bytes for UTF-8 encodings are set for characters greater than 127 when in
651        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
652        altogether.)
653    
654    20. Added the /T option to pcretest so as to be able to run tests with non-
655        standard character tables, thus making it possible to include the tests
656        used for 19 above in the standard set of tests.
657    
658    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
659        reference to a subpattern the other side of a comment that contains an
660        opening parenthesis caused either an internal compiling error, or a
661        reference to the wrong subpattern.
662    
663    
664    Version 8.02 19-Mar-2010
665    ------------------------
666    
667    1.  The Unicode data tables have been updated to Unicode 5.2.0.
668    
669    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
670        configured.
671    
672    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
673        original author of that file, following a query about its status.
674    
675    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
676        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
677    
678    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
679        quantifier applied to a forward-referencing subroutine call, could compile
680        incorrect code or give the error "internal error: previously-checked
681        referenced subpattern not found".
682    
683    6.  Both MS Visual Studio and Symbian OS have problems with initializing
684        variables to point to external functions. For these systems, therefore,
685        pcre_malloc etc. are now initialized to local functions that call the
686        relevant global functions.
687    
688    7.  There were two entries missing in the vectors called coptable and poptable
689        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
690        I've fixed the data, and added a kludgy way of testing at compile time that
691        the lengths are correct (equal to the number of opcodes).
692    
693    8.  Following on from 7, I added a similar kludge to check the length of the
694        eint vector in pcreposix.c.
695    
696    9.  Error texts for pcre_compile() are held as one long string to avoid too
697        much relocation at load time. To find a text, the string is searched,
698        counting zeros. There was no check for running off the end of the string,
699        which could happen if a new error number was added without updating the
700        string.
701    
702    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
703    
704    11. \K was not working if it appeared in an atomic group or in a group that
705        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
706        \K is "not well defined" if used in an assertion. PCRE now accepts it if
707        the assertion is positive, but not if it is negative.
708    
709    12. Change 11 fortuitously reduced the size of the stack frame used in the
710        "match()" function of pcre_exec.c by one pointer. Forthcoming
711        implementation of support for (*MARK) will need an extra pointer on the
712        stack; I have reserved it now, so that the stack frame size does not
713        decrease.
714    
715    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
716        item in branch that calls a recursion is a subroutine call - as in the
717        second branch in the above example - was incorrectly given the compile-
718        time error "recursive call could loop indefinitely" because pcre_compile()
719        was not correctly checking the subroutine for matching a non-empty string.
720    
721    14. The checks for overrunning compiling workspace could trigger after an
722        overrun had occurred. This is a "should never occur" error, but it can be
723        triggered by pathological patterns such as hundreds of nested parentheses.
724        The checks now trigger 100 bytes before the end of the workspace.
725    
726    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
727    
728    
729    Version 8.01 19-Jan-2010
730    ------------------------
731    
732    1.  If a pattern contained a conditional subpattern with only one branch (in
733        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
734        computed the wrong minimum data length (which is of course zero for such
735        subpatterns). This could cause incorrect "no match" results.
736    
737    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
738        the pattern is reset in the first branch, pcre_compile() failed with
739        "internal error: code overflow at offset...". This happened only when
740        the reset was to the original external option setting. (An optimization
741        abstracts leading options settings into an external setting, which was the
742        cause of this.)
743    
744    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
745        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
746        assertion pattern did not match (meaning that the assertion was true), it
747        was incorrectly treated as false if the SKIP had been reached during the
748        matching. This also applied to assertions used as conditions.
749    
750    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
751        assertion subpattern, including such a pattern used as a condition,
752        unpredictable results occurred, instead of the error return
753        PCRE_ERROR_DFA_UITEM.
754    
755    5.  The C++ GlobalReplace function was not working like Perl for the special
756        situation when an empty string is matched. It now does the fancy magic
757        stuff that is necessary.
758    
759    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
760        removed. (These were left over from very, very early versions of PCRE.)
761    
762    7.  Some cosmetic changes to the code to make life easier when compiling it
763        as part of something else:
764    
765        (a) Change DEBUG to PCRE_DEBUG.
766    
767        (b) In pcre_compile(), rename the member of the "branch_chain" structure
768            called "current" as "current_branch", to prevent a collision with the
769            Linux macro when compiled as a kernel module.
770    
771        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
772            prevent a collision with the Linux macro when compiled as a kernel
773            module.
774    
775    8.  In pcre_compile() there are some checks for integer overflows that used to
776        cast potentially large values to (double). This has been changed to that
777        when building, a check for int64_t is made, and if it is found, it is used
778        instead, thus avoiding the use of floating point arithmetic. (There is no
779        other use of FP in PCRE.) If int64_t is not found, the fallback is to
780        double.
781    
782    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
783        2005 (difference between two addresses compared to an unsigned value).
784    
785    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
786        custom one, because of the following reported problem in Windows:
787    
788          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
789              under Win32.
790          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
791              therefore missing the function definition.
792          - The compiler thus generates a "C" signature for the test function.
793          - The linker fails to find the "C" function.
794          - PCRE fails to configure if asked to do so against libbz2.
795    
796    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
797        messages were output:
798    
799          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
800          rerunning libtoolize, to keep the correct libtool macros in-tree.
801          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
802    
803        I have done both of these things.
804    
805    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
806        most of the time, it *can* run out if it is given a pattern that contains a
807        runaway infinite recursion. I updated the discussion in the pcrestack man
808        page.
809    
810    13. Now that we have gone to the x.xx style of version numbers, the minor
811        version may start with zero. Using 08 or 09 is a bad idea because users
812        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
813        interpreted as invalid octal numbers. I've updated the previous comment in
814        configure.ac, and also added a check that gives an error if 08 or 09 are
815        used.
816    
817    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
818        causing partial matching to fail when the end of the subject matched \W
819        in a UTF-8 pattern where \W was quantified with a minimum of 3.
820    
821    15. There were some discrepancies between the declarations in pcre_internal.h
822        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
823        their definitions. The declarations used "const uschar *" and the
824        definitions used USPTR. Even though USPTR is normally defined as "const
825        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
826        reported that: "This difference in casting confuses some C++ compilers, for
827        example, SunCC recognizes above declarations as different functions and
828        generates broken code for hbpcre." I have changed the declarations to use
829        USPTR.
830    
831    16. GNU libtool is named differently on some systems. The autogen.sh script now
832        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
833        (FreeBSD).
834    
835    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
836        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
837        comment: "Figure out how to create a longlong from a string: strtoll and
838        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
839        instance, but it only takes 2 args instead of 3!"
840    
841    18. A subtle bug concerned with back references has been fixed by a change of
842        specification, with a corresponding code fix. A pattern such as
843        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
844        refers, was giving matches when it shouldn't. For example, xa=xaaa would
845        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
846        same bug. Such groups have to be quantified to be useful, or contained
847        inside another quantified group. (If there's no repetition, the reference
848        can never match.) The problem arises because, having left the group and
849        moved on to the rest of the pattern, a later failure that backtracks into
850        the group uses the captured value from the final iteration of the group
851        rather than the correct earlier one. I have fixed this in PCRE by forcing
852        any group that contains a reference to itself to be an atomic group; that
853        is, there cannot be any backtracking into it once it has completed. This is
854        similar to recursive and subroutine calls.
855    
856    
857    Version 8.00 19-Oct-09
858    ----------------------
859    
860    1.  The table for translating pcre_compile() error codes into POSIX error codes
861        was out-of-date, and there was no check on the pcre_compile() error code
862        being within the table. This could lead to an OK return being given in
863        error.
864    
865    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
866        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
867        in a Windows environment.
868    
869    3.  The pcregrep --count option prints the count for each file even when it is
870        zero, as does GNU grep. However, pcregrep was also printing all files when
871        --files-with-matches was added. Now, when both options are given, it prints
872        counts only for those files that have at least one match. (GNU grep just
873        prints the file name in this circumstance, but including the count seems
874        more useful - otherwise, why use --count?) Also ensured that the
875        combination -clh just lists non-zero counts, with no names.
876    
877    4.  The long form of the pcregrep -F option was incorrectly implemented as
878        --fixed_strings instead of --fixed-strings. This is an incompatible change,
879        but it seems right to fix it, and I didn't think it was worth preserving
880        the old behaviour.
881    
882    5.  The command line items --regex=pattern and --regexp=pattern were not
883        recognized by pcregrep, which required --regex pattern or --regexp pattern
884        (with a space rather than an '='). The man page documented the '=' forms,
885        which are compatible with GNU grep; these now work.
886    
887    6.  No libpcreposix.pc file was created for pkg-config; there was just
888        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
889    
890    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
891        when UCP support is not needed, by modifying the Python script that
892        generates it from Unicode data files. This should not matter if the module
893        is correctly used as a library, but I received one complaint about 50K of
894        unwanted data. My guess is that the person linked everything into his
895        program rather than using a library. Anyway, it does no harm.
896    
897    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
898        was a minimum greater than 1 for a wide character in a possessive
899        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
900        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
901        character. Chaos in the form of incorrect output or a compiling loop could
902        result.
903    
904    9.  The restrictions on what a pattern can contain when partial matching is
905        requested for pcre_exec() have been removed. All patterns can now be
906        partially matched by this function. In addition, if there are at least two
907        slots in the offset vector, the offset of the earliest inspected character
908        for the match and the offset of the end of the subject are set in them when
909        PCRE_ERROR_PARTIAL is returned.
910    
911    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
912        synonymous with PCRE_PARTIAL, for backwards compatibility, and
913        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
914        and may be more useful for multi-segment matching.
915    
916    11. Partial matching with pcre_exec() is now more intuitive. A partial match
917        used to be given if ever the end of the subject was reached; now it is
918        given only if matching could not proceed because another character was
919        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
920        string "Z", which now yields "no match" instead of "partial match". In the
921        case of pcre_dfa_exec(), "no match" is given if every matching path for the
922        final character ended with (*FAIL).
923    
924    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
925        if the pattern had a "must contain" character that was already found in the
926        earlier partial match, unless partial matching was again requested. For
927        example, with the pattern /dog.(body)?/, the "must contain" character is
928        "g". If the first part-match was for the string "dog", restarting with
929        "sbody" failed. This bug has been fixed.
930    
931    13. The string returned by pcre_dfa_exec() after a partial match has been
932        changed so that it starts at the first inspected character rather than the
933        first character of the match. This makes a difference only if the pattern
934        starts with a lookbehind assertion or \b or \B (\K is not supported by
935        pcre_dfa_exec()). It's an incompatible change, but it makes the two
936        matching functions compatible, and I think it's the right thing to do.
937    
938    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
939        so that the demonstration program is easily available in environments where
940        PCRE has not been installed from source.
941    
942    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
943        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
944        library.
945    
946    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
947        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
948        is not the first non-POSIX option to be added. Clearly some people find
949        these options useful.
950    
951    17. If a caller to the POSIX matching function regexec() passes a non-zero
952        value for nmatch with a NULL value for pmatch, the value of
953        nmatch is forced to zero.
954    
955    18. RunGrepTest did not have a test for the availability of the -u option of
956        the diff command, as RunTest does. It now checks in the same way as
957        RunTest, and also checks for the -b option.
958    
959    19. If an odd number of negated classes containing just a single character
960        interposed, within parentheses, between a forward reference to a named
961        subpattern and the definition of the subpattern, compilation crashed with
962        an internal error, complaining that it could not find the referenced
963        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
964        [The bug was that it was starting one character too far in when skipping
965        over the character class, thus treating the ] as data rather than
966        terminating the class. This meant it could skip too much.]
967    
968    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
969        /g option in pcretest when the pattern contains \K, which makes it possible
970        to have an empty string match not at the start, even when the pattern is
971        anchored. Updated pcretest and pcredemo to use this option.
972    
973    21. If the maximum number of capturing subpatterns in a recursion was greater
974        than the maximum at the outer level, the higher number was returned, but
975        with unset values at the outer level. The correct (outer level) value is
976        now given.
977    
978    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
979        PCRE did not set those parentheses (unlike Perl). I have now found a way to
980        make it do so. The string so far is captured, making this feature
981        compatible with Perl.
982    
983    23. The tests have been re-organized, adding tests 11 and 12, to make it
984        possible to check the Perl 5.10 features against Perl 5.10.
985    
986    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
987        pattern matches a fixed length string. PCRE did not allow this; now it
988        does. Neither allows recursion.
989    
990    25. I finally figured out how to implement a request to provide the minimum
991        length of subject string that was needed in order to match a given pattern.
992        (It was back references and recursion that I had previously got hung up
993        on.) This code has now been added to pcre_study(); it finds a lower bound
994        to the length of subject needed. It is not necessarily the greatest lower
995        bound, but using it to avoid searching strings that are too short does give
996        some useful speed-ups. The value is available to calling programs via
997        pcre_fullinfo().
998    
999    26. While implementing 25, I discovered to my embarrassment that pcretest had
1000        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1001        study optimizations had never been tested with that matching function.
1002        Oops. What is worse, even when it was passed study data, there was a bug in
1003        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1004        were also very few tests of studied patterns with pcre_dfa_exec().
1005    
1006    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1007        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1008        on the other side of the coin, they are no longer allowed to have different
1009        names, because these cannot be distinguished in PCRE, and this has caused
1010        confusion. (This is a difference from Perl.)
1011    
1012    28. When duplicate subpattern names are present (necessarily with different
1013        numbers, as required by 27 above), and a test is made by name in a
1014        conditional pattern, either for a subpattern having been matched, or for
1015        recursion in such a pattern, all the associated numbered subpatterns are
1016        tested, and the overall condition is true if the condition is true for any
1017        one of them. This is the way Perl works, and is also more like the way
1018        testing by number works.
1019    
1020    
1021    Version 7.9 11-Apr-09
1022    ---------------------
1023    
1024    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1025        (pcretest), all targets were linked against these libraries. This included
1026        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1027        libraries. This caused unwanted dependencies to be created. This problem
1028        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1029        pcretest is linked with readline.
1030    
1031    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1032        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1033        moved outside it again, because FALSE and TRUE are already defined in AIX,
1034        but BOOL is not.
1035    
1036    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1037        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1038    
1039    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1040        hyphens) following file names and line numbers when outputting matching
1041        lines. This is not true; no spaces are inserted. I have also clarified the
1042        wording for the --colour (or --color) option.
1043    
1044    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1045        was not coloured; this is different to GNU grep, so I have changed it to be
1046        the same.
1047    
1048    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1049        each matching line was coloured. Now it goes on to look for further matches
1050        of any of the test patterns, which is the same behaviour as GNU grep.
1051    
1052    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1053        doesn't make sense to accept an empty string match in pcregrep, so I have
1054        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1055        seems to be how GNU grep behaves.
1056    
1057    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1058        start or after a newline", because the conditional assertion was not being
1059        correctly handled. The rule now is that both the assertion and what follows
1060        in the first alternative must satisfy the test.
1061    
1062    9.  If auto-callout was enabled in a pattern with a conditional group whose
1063        condition was an assertion, PCRE could crash during matching, both with
1064        pcre_exec() and pcre_dfa_exec().
1065    
1066    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1067        used for matching.
1068    
1069    11. Unicode property support in character classes was not working for
1070        characters (bytes) greater than 127 when not in UTF-8 mode.
1071    
1072    12. Added the -M command line option to pcretest.
1073    
1074    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1075    
1076    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1077    
1078    16. Added comments and documentation about mis-use of no_arg in the C++
1079        wrapper.
1080    
1081    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1082        from Martin Jerabek that uses macro names for all relevant character and
1083        string constants.
1084    
1085    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1086        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1087        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1088        these, but not everybody uses configure.
1089    
1090    19. A conditional group that had only one branch was not being correctly
1091        recognized as an item that could match an empty string. This meant that an
1092        enclosing group might also not be so recognized, causing infinite looping
1093        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1094        with the subject "ab", where knowledge that the repeated group can match
1095        nothing is needed in order to break the loop.
1096    
1097    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1098        exec(), but without supplying a callout function, matching went wrong.
1099    
1100    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1101        leak if the size of the offset vector was greater than 30. When the vector
1102        is smaller, the saved offsets during recursion go onto a local stack
1103        vector, but for larger vectors malloc() is used. It was failing to free
1104        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1105        error, in fact).
1106    
1107    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1108        heapframe that is used only when UTF-8 support is enabled. This caused no
1109        problem, but was untidy.
1110    
1111    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1112        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1113        included within another project.
1114    
1115    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1116        slightly modified by me:
1117    
1118          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1119              not building pcregrep.
1120    
1121          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1122              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1123    
1124    25. Forward references, both numeric and by name, in patterns that made use of
1125        duplicate group numbers, could behave incorrectly or give incorrect errors,
1126        because when scanning forward to find the reference group, PCRE was not
1127        taking into account the duplicate group numbers. A pattern such as
1128        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1129    
1130    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1131        the feature of a custom pointer more persuasive (as requested by a user).
1132    
1133    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1134        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1135        pre-defined.
1136    
1137    28. Added support for (*UTF8) at the start of a pattern.
1138    
1139    29. Arrange for flags added by the "release type" setting in CMake to be shown
1140        in the configuration summary.
1141    
1142    
1143    Version 7.8 05-Sep-08
1144    ---------------------
1145    
1146    1.  Replaced UCP searching code with optimized version as implemented for Ad
1147        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1148        stage table and inline lookup instead of a function, giving speed ups of 2
1149        to 5 times on some simple patterns that I tested. Permission was given to
1150        distribute the MultiStage2.py script that generates the tables (it's not in
1151        the tarball, but is in the Subversion repository).
1152    
1153    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1154        scripts.
1155    
1156    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1157        a group with a zero qualifier. The result of the study could be incorrect,
1158        or the function might crash, depending on the pattern.
1159    
1160    4.  Caseless matching was not working for non-ASCII characters in back
1161        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1162        It now works when Unicode Property Support is available.
1163    
1164    5.  In pcretest, an escape such as \x{de} in the data was always generating
1165        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1166        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1167        truncation.
1168    
1169    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1170    
1171    7.  Added two (int) casts to pcregrep when printing the difference of two
1172        pointers, in case they are 64-bit values.
1173    
1174    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1175        test 2 if it fails.
1176    
1177    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1178        and a #define of that name to empty if it is not externally set. This is to
1179        allow users of MSVC to set it if necessary.
1180    
1181    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1182        the convenience functions in the pcre_get.c source file.
1183    
1184    11. An option change at the start of a pattern that had top-level alternatives
1185        could cause overwriting and/or a crash. This command provoked a crash in
1186        some environments:
1187    
1188          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1189    
1190        This potential security problem was recorded as CVE-2008-2371.
1191    
1192    12. For a pattern where the match had to start at the beginning or immediately
1193        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1194        pcre_dfa_exec() could read past the end of the passed subject if there was
1195        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1196        pcretest so that it places the subject at the end of its malloc-ed buffer.
1197    
1198    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1199        exec() might read past the end of the data buffer in UTF-8 mode.
1200    
1201    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1202        the data contained the byte 0x85 as part of a UTF-8 character within its
1203        first line. This applied both to normal and DFA matching.
1204    
1205    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1206        /^[^d]*?$/8 failed to match "abc".
1207    
1208    16. Added a missing copyright notice to pcrecpp_internal.h.
1209    
1210    17. Make it more clear in the documentation that values returned from
1211        pcre_exec() in ovector are byte offsets, not character counts.
1212    
1213    18. Tidied a few places to stop certain compilers from issuing warnings.
1214    
1215    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1216        supplied by Stefan Weber. I made a further small update for 7.8 because
1217        there is a change of source arrangements: the pcre_searchfuncs.c module is
1218        replaced by pcre_ucd.c.
1219    
1220    
1221    Version 7.7 07-May-08
1222  ---------------------  ---------------------
1223    
1224  1.  Applied Craig's patch to sort out a long long problem: "If we can't convert  1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1225      a string to a long long, pretend we don't even have a long long." This is      a string to a long long, pretend we don't even have a long long." This is
1226      done by checking for the strtoq, strtoll, and _strtoi64 functions.      done by checking for the strtoq, strtoll, and _strtoi64 functions.
1227    
1228  2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with  2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1229      pre-7.6 versions, which defined a global no_arg variable instead of putting      pre-7.6 versions, which defined a global no_arg variable instead of putting
1230      it in the RE class.      it in the RE class. (See also #8 below.)
1231    
1232  3.  Remove a line of dead code, identified by coverity and reported by Nuno  3.  Remove a line of dead code, identified by coverity and reported by Nuno
1233      Lopes.      Lopes.
1234    
1235  4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:  4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1236    
1237      (1) The include/exclude patterns were being applied to the whole pathnames      (1) The include/exclude patterns were being applied to the whole pathnames
1238          of files, instead of just to the final components.          of files, instead of just to the final components.
1239    
1240      (2) If there was more than one level of directory, the subdirectories were      (2) If there was more than one level of directory, the subdirectories were
1241          skipped unless they satisfied the include/exclude conditions. This is          skipped unless they satisfied the include/exclude conditions. This is
1242          inconsistent with GNU grep (and could even be seen as contrary to the          inconsistent with GNU grep (and could even be seen as contrary to the
1243          pcregrep specification - which I improved to make it absolutely clear).          pcregrep specification - which I improved to make it absolutely clear).
1244          The action now is always to scan all levels of directory, and just          The action now is always to scan all levels of directory, and just
1245          apply the include/exclude patterns to regular files.          apply the include/exclude patterns to regular files.
1246    
1247  5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used  5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1248      --exclude_dir in the tests to avoid scanning .svn directories.      --exclude_dir in the tests to avoid scanning .svn directories.
1249    
1250  6.  Applied Craig's patch to the QuoteMeta function so that it escapes the  6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1251      NUL character as backslash + 0 rather than backslash + NUL, because PCRE      NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1252      doesn't support NULs in patterns.      doesn't support NULs in patterns.
1253    
1254  7.  Added some missing "const"s to declarations of static tables in  7.  Added some missing "const"s to declarations of static tables in
1255      pcre_compile.c and pcre_dfa_exec.c.      pcre_compile.c and pcre_dfa_exec.c.
1256    
1257  8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was  8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1258      caused by fix #2  above. (Subsequently also a second patch to fix the      caused by fix #2  above. (Subsequently also a second patch to fix the
1259      first patch. And a third patch - this was a messy problem.)      first patch. And a third patch - this was a messy problem.)
1260    
1261    9.  Applied Craig's patch to remove the use of push_back().
1262    
1263    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1264        matching function regexec().
1265    
1266    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1267        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1268        references. PCRE supports relative numbers with this syntax (I don't think
1269        Oniguruma does).
1270    
1271    12. Previously, a group with a zero repeat such as (...){0} was completely
1272        omitted from the compiled regex. However, this means that if the group
1273        was called as a subroutine from elsewhere in the pattern, things went wrong
1274        (an internal error was given). Such groups are now left in the compiled
1275        pattern, with a new opcode that causes them to be skipped at execution
1276        time.
1277    
1278    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1279        to the way PCRE behaves:
1280    
1281        (a) A lone ] character is dis-allowed (Perl treats it as data).
1282    
1283        (b) A back reference to an unmatched subpattern matches an empty string
1284            (Perl fails the current match path).
1285    
1286        (c) A data ] in a character class must be notated as \] because if the
1287            first data character in a class is ], it defines an empty class. (In
1288            Perl it is not possible to have an empty class.) The empty class []
1289            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1290            The negative empty class [^] matches any one character, independently
1291            of the DOTALL setting.
1292    
1293    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1294        non-existent subpattern following a character class starting with ']' and
1295        containing () gave an internal compiling error instead of "reference to
1296        non-existent subpattern". Fortunately, when the pattern did exist, the
1297        compiled code was correct. (When scanning forwards to check for the
1298        existencd of the subpattern, it was treating the data ']' as terminating
1299        the class, so got the count wrong. When actually compiling, the reference
1300        was subsequently set up correctly.)
1301    
1302    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1303        it was being rejected as not supported by pcre_dfa_exec(), even though
1304        other assertions are supported. I have made pcre_dfa_exec() support
1305        (*FAIL).
1306    
1307    16. The implementation of 13c above involved the invention of a new opcode,
1308        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1309        cannot be changed at match time, I realized I could make a small
1310        improvement to matching performance by compiling OP_ALLANY instead of
1311        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1312        on the OP_ANY path.
1313    
1314    17. Compiling pcretest on Windows with readline support failed without the
1315        following two fixes: (1) Make the unistd.h include conditional on
1316        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1317    
1318    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1319        ncurses library to be included for pcretest when ReadLine support is
1320        requested, but also to allow for it to be overridden. This patch came from
1321        Daniel Bergström.
1322    
1323    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1324        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1325        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1326        spotting this.
1327    
1328    
1329  Version 7.6 28-Jan-08  Version 7.6 28-Jan-08

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