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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    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    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
44    
45    10. Add a cast and remove a redundant test from the code.
46    
47    11. JIT should use pcre_malloc/pcre_free for allocation.
48    
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
52    
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
54    
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
57    
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". This
60        is now checked, and causes "too many forward references" instead.
61    
62    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
63        incorrectly expecting the subject to contain another "a" after the start.
64    
65    
66    Version 8.20 21-Oct-2011
67    ------------------------
68    
69    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
70        a POSIX class. After further experiments with Perl, which convinced me that
71        Perl has bugs and confusions, a closing square bracket is no longer allowed
72        in a POSIX name. This bug also affected patterns with classes that started
73        with full stops.
74    
75    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
76        captured substring, but while checking the failing first alternative,
77        substring 1 is temporarily captured. If the output vector supplied to
78        pcre_exec() was not big enough for this capture, the yield of the function
79        was still zero ("insufficient space for captured substrings"). This cannot
80        be totally fixed without adding another stack variable, which seems a lot
81        of expense for a edge case. However, I have improved the situation in cases
82        such as /(a)(b)x|abc/ matched against "abc", where the return code
83        indicates that fewer than the maximum number of slots in the ovector have
84        been set.
85    
86    3.  Related to (2) above: when there are more back references in a pattern than
87        slots in the output vector, pcre_exec() uses temporary memory during
88        matching, and copies in the captures as far as possible afterwards. It was
89        using the entire output vector, but this conflicts with the specification
90        that only 2/3 is used for passing back captured substrings. Now it uses
91        only the first 2/3, for compatibility. This is, of course, another edge
92        case.
93    
94    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
95        main code base, and can be used by building with --enable-jit. When this is
96        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
97        runtime --no-jit option is given.
98    
99    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
100        ovector, the return from the function was zero, implying that there were
101        other matches that did not fit. The correct "exactly full" value is now
102        returned.
103    
104    6.  If a subpattern that was called recursively or as a subroutine contained
105        (*PRUNE) or any other control that caused it to give a non-standard return,
106        invalid errors such as "Error -26 (nested recursion at the same subject
107        position)" or even infinite loops could occur.
108    
109    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
110        computing the minimum length on reaching *ACCEPT, and so ended up with the
111        wrong value of 1 rather than 0. Further investigation indicates that
112        computing a minimum subject length in the presence of *ACCEPT is difficult
113        (think back references, subroutine calls), and so I have changed the code
114        so that no minimum is registered for a pattern that contains *ACCEPT.
115    
116    8.  If (*THEN) was present in the first (true) branch of a conditional group,
117        it was not handled as intended. [But see 16 below.]
118    
119    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
120        Sheri Pierce.
121    
122    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
123        the first byte in a match must be "a".
124    
125    11. Change 17 for 8.13 increased the recursion depth for patterns like
126        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
127        pattern contains any instances of (*THEN). If it does not, the old
128        optimizations are restored. It would be nice to do this on a per-group
129        basis, but at the moment that is not feasible.
130    
131    12. In some environments, the output of pcretest -C is CRLF terminated. This
132        broke RunTest's code that checks for the link size. A single white space
133        character after the value is now allowed for.
134    
135    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
136        For "fr", it uses the Windows-specific input and output files.
137    
138    14. If (*THEN) appeared in a group that was called recursively or as a
139        subroutine, it did not work as intended. [But see next item.]
140    
141    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
142        pattern fragments (but not containing any | characters). If A and B are
143        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
144        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
145        D. In other words, Perl considers parentheses that do not contain any |
146        characters to be part of a surrounding alternative, whereas PCRE was
147        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
148        differently. PCRE now behaves in the same way as Perl, except in the case
149        of subroutine/recursion calls such as (?1) which have in any case always
150        been different (but PCRE had them first :-).
151    
152    16. Related to 15 above: Perl does not treat the | in a conditional group as
153        creating alternatives. Such a group is treated in the same way as an
154        ordinary group without any | characters when processing (*THEN). PCRE has
155        been changed to match Perl's behaviour.
156    
157    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
158        RunGrepTest script failed.
159    
160    18. Change 22 for version 13 caused atomic groups to use more stack. This is
161        inevitable for groups that contain captures, but it can lead to a lot of
162        stack use in large patterns. The old behaviour has been restored for atomic
163        groups that do not contain any capturing parentheses.
164    
165    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
166        suppress the check for a minimum subject length at run time. (If it was
167        given to pcre_exec() or pcre_dfa_exec() it did work.)
168    
169    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
170        fail to work when decoding hex characters in data strings in EBCDIC
171        environments.
172    
173    21. It appears that in at least one Mac OS environment, the isxdigit() function
174        is implemented as a macro that evaluates to its argument more than once,
175        contravening the C 90 Standard (I haven't checked a later standard). There
176        was an instance in pcretest which caused it to go wrong when processing
177        \x{...} escapes in subject strings. The has been rewritten to avoid using
178        things like p++ in the argument of isxdigit().
179    
180    
181    Version 8.13 16-Aug-2011
182    ------------------------
183    
184    1.  The Unicode data tables have been updated to Unicode 6.0.0.
185    
186    2.  Two minor typos in pcre_internal.h have been fixed.
187    
188    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
189        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
190        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
191    
192    4.  There were a number of related bugs in the code for matching backrefences
193        caselessly in UTF-8 mode when codes for the characters concerned were
194        different numbers of bytes. For example, U+023A and U+2C65 are an upper
195        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
196        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
197        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
198        2-byte code at the end of the subject (it thought there wasn't enough data
199        left).
200    
201    5.  Comprehensive information about what went wrong is now returned by
202        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
203        as the output vector has at least 2 elements. The offset of the start of
204        the failing character and a reason code are placed in the vector.
205    
206    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
207        now returned is for the first byte of the failing character, instead of the
208        last byte inspected. This is an incompatible change, but I hope it is small
209        enough not to be a problem. It makes the returned offset consistent with
210        pcre_exec() and pcre_dfa_exec().
211    
212    7.  pcretest now gives a text phrase as well as the error number when
213        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
214        failure, the offset and reason code are output.
215    
216    8.  When \R was used with a maximizing quantifier it failed to skip backwards
217        over a \r\n pair if the subsequent match failed. Instead, it just skipped
218        back over a single character (\n). This seems wrong (because it treated the
219        two characters as a single entity when going forwards), conflicts with the
220        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
221        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
222        has been changed.
223    
224    9.  Some internal refactoring has changed the processing so that the handling
225        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
226        time (the PCRE_DOTALL option was changed this way some time ago: version
227        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
228        which was always a bit of a fudge. It also means that there is one less
229        argument for the match() function, which reduces its stack requirements
230        slightly. This change also fixes an incompatibility with Perl: the pattern
231        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
232    
233    10. More internal refactoring has drastically reduced the number of recursive
234        calls to match() for possessively repeated groups such as (abc)++ when
235        using pcre_exec().
236    
237    11. While implementing 10, a number of bugs in the handling of groups were
238        discovered and fixed:
239    
240        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
241        (a|)*(?1) gave a compile-time internal error.
242        ((a|)+)+  did not notice that the outer group could match an empty string.
243        (^a|^)+   was not marked as anchored.
244        (.*a|.*)+ was not marked as matching at start or after a newline.
245    
246    12. Yet more internal refactoring has removed another argument from the match()
247        function. Special calls to this function are now indicated by setting a
248        value in a variable in the "match data" data block.
249    
250    13. Be more explicit in pcre_study() instead of relying on "default" for
251        opcodes that mean there is no starting character; this means that when new
252        ones are added and accidentally left out of pcre_study(), testing should
253        pick them up.
254    
255    14. The -s option of pcretest has been documented for ages as being an old
256        synonym of -m (show memory usage). I have changed it to mean "force study
257        for every regex", that is, assume /S for every regex. This is similar to -i
258        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
259        using it. It makes it easier to run collections of tests with and without
260        study enabled, and thereby test pcre_study() more easily. All the standard
261        tests are now run with and without -s (but some patterns can be marked as
262        "never study" - see 20 below).
263    
264    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
265        restoration of the capturing data to the outer values was not happening
266        correctly.
267    
268    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
269        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
270        pattern had matched an empty string, and so incorrectly returned a no
271        match.
272    
273    17. There was optimizing code for the last branch of non-capturing parentheses,
274        and also for the obeyed branch of a conditional subexpression, which used
275        tail recursion to cut down on stack usage. Unfortunately, now that there is
276        the possibility of (*THEN) occurring in these branches, tail recursion is
277        no longer possible because the return has to be checked for (*THEN). These
278        two optimizations have therefore been removed. [But see 8.20/11 above.]
279    
280    18. If a pattern containing \R was studied, it was assumed that \R always
281        matched two bytes, thus causing the minimum subject length to be
282        incorrectly computed because \R can also match just one byte.
283    
284    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
285        was incorrectly computed.
286    
287    20. If /S is present twice on a test pattern in pcretest input, it now
288        *disables* studying, thereby overriding the use of -s on the command line
289        (see 14 above). This is necessary for one or two tests to keep the output
290        identical in both cases.
291    
292    21. When (*ACCEPT) was used in an assertion that matched an empty string and
293        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
294    
295    22. When an atomic group that contained a capturing parenthesis was
296        successfully matched, but the branch in which it appeared failed, the
297        capturing was not being forgotten if a higher numbered group was later
298        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
299        group 1 to "a", when in fact it should be unset. This applied to multi-
300        branched capturing and non-capturing groups, repeated or not, and also to
301        positive assertions (capturing in negative assertions does not happen
302        in PCRE) and also to nested atomic groups.
303    
304    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
305        subject after a captured substring, to make it easier to tell which of a
306        number of identical substrings has been captured.
307    
308    24. The way atomic groups are processed by pcre_exec() has been changed so that
309        if they are repeated, backtracking one repetition now resets captured
310        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
311        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
312        "aaa". Previously, it would have been "a". As part of this code
313        refactoring, the way recursive calls are handled has also been changed.
314    
315    25. If an assertion condition captured any substrings, they were not passed
316        back unless some other capturing happened later. For example, if
317        (?(?=(a))a) was matched against "a", no capturing was returned.
318    
319    26. When studying a pattern that contained subroutine calls or assertions,
320        the code for finding the minimum length of a possible match was handling
321        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
322        group 1 called group 2 while simultaneously a separate group 2 called group
323        1). A stack overflow occurred in this case. I have fixed this by limiting
324        the recursion depth to 10.
325    
326    27. Updated RunTest.bat in the distribution to the version supplied by Tom
327        Fortmann. This supports explicit test numbers on the command line, and has
328        argument validation and error reporting.
329    
330    28. An instance of \X with an unlimited repeat could fail if at any point the
331        first character it looked at was a mark character.
332    
333    29. Some minor code refactoring concerning Unicode properties and scripts
334        should reduce the stack requirement of match() slightly.
335    
336    30. Added the '=' option to pcretest to check the setting of unused capturing
337        slots at the end of the pattern, which are documented as being -1, but are
338        not included in the return count.
339    
340    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
341        compiled something random. Now it gives a compile-time error (as does
342        Perl).
343    
344    32. A *MARK encountered during the processing of a positive assertion is now
345        recorded and passed back (compatible with Perl).
346    
347    33. If --only-matching or --colour was set on a pcregrep call whose pattern
348        had alternative anchored branches, the search for a second match in a line
349        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
350        matched the line "0102" twice. The same bug affected patterns that started
351        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
352        twice.
353    
354    34. Previously, PCRE did not allow quantification of assertions. However, Perl
355        does, and because of capturing effects, quantifying parenthesized
356        assertions may at times be useful. Quantifiers are now allowed for
357        parenthesized assertions.
358    
359    35. A minor code tidy in pcre_compile() when checking options for \R usage.
360    
361    36. \g was being checked for fancy things in a character class, when it should
362        just be a literal "g".
363    
364    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
365        appearance of a nested POSIX class supersedes an apparent external class.
366        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
367        unescaped square brackets may also appear as part of class names. For
368        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
369        more like Perl. (But see 8.20/1 above.)
370    
371    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
372        was because it thought it was \N{name}, which is not supported).
373    
374    39. Add minix to OS list not supporting the -S option in pcretest.
375    
376    40. PCRE tries to detect cases of infinite recursion at compile time, but it
377        cannot analyze patterns in sufficient detail to catch mutual recursions
378        such as ((?1))((?2)). There is now a runtime test that gives an error if a
379        subgroup is called recursively as a subpattern for a second time at the
380        same position in the subject string. In previous releases this might have
381        been caught by the recursion limit, or it might have run out of stack.
382    
383    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
384        happen only once. PCRE was, however incorrectly giving a compile time error
385        "recursive call could loop indefinitely" because it cannot analyze the
386        pattern in sufficient detail. The compile time test no longer happens when
387        PCRE is compiling a conditional subpattern, but actual runaway loops are
388        now caught at runtime (see 40 above).
389    
390    42. It seems that Perl allows any characters other than a closing parenthesis
391        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
392        has been changed to be the same.
393    
394    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
395        as not to get warnings when autogen.sh is called. Also changed
396        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
397    
398    44. To help people who use pcregrep to scan files containing exceedingly long
399        lines, the following changes have been made:
400    
401        (a) The default value of the buffer size parameter has been increased from
402            8K to 20K. (The actual buffer used is three times this size.)
403    
404        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
405            PCRE is built.
406    
407        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
408            to be set at run time.
409    
410        (d) Numerical values in pcregrep options can be followed by K or M, for
411            example --buffer-size=50K.
412    
413        (e) If a line being scanned overflows pcregrep's buffer, an error is now
414            given and the return code is set to 2.
415    
416    45. Add a pointer to the latest mark to the callout data block.
417    
418    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
419        partial match of an empty string instead of no match. This was specific to
420        the use of ".".
421    
422    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
423        complete match instead of a partial match. This bug was dependent on both
424        the PCRE_UTF8 and PCRE_DOTALL options being set.
425    
426    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
427        starting byte set, because \b was not being ignored.
428    
429    
430    Version 8.12 15-Jan-2011
431    ------------------------
432    
433    1.  Fixed some typos in the markup of the man pages, and wrote a script that
434        checks for such things as part of the documentation building process.
435    
436    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
437        --match-limit and --recursion-limit options (added for 8.11). In
438        particular, this made one of the standard tests fail. (The integer value
439        went into the wrong half of a long int.)
440    
441    3.  If the --colour option was given to pcregrep with -v (invert match), it
442        did strange things, either producing crazy output, or crashing. It should,
443        of course, ignore a request for colour when reporting lines that do not
444        match.
445    
446    4.  Another pcregrep bug caused similar problems if --colour was specified with
447        -M (multiline) and the pattern match finished with a line ending.
448    
449    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
450        matched in multiline mode, the following line was shown as part of the
451        match. This seems wrong, so I have changed it.
452    
453    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
454        the check for further matches in the same line (so they could be coloured)
455        to overrun the end of the current line. If another match was found, it was
456        incorrectly shown (and then shown again when found in the next line).
457    
458    7.  If pcregrep was compiled under Windows, there was a reference to the
459        function pcregrep_exit() before it was defined. I am assuming this was
460        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
461        reported by a user. I've moved the definition above the reference.
462    
463    
464    Version 8.11 10-Dec-2010
465    ------------------------
466    
467    1.  (*THEN) was not working properly if there were untried alternatives prior
468        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
469        backtracked to try for "b" instead of moving to the next alternative branch
470        at the same level (in this case, to look for "c"). The Perl documentation
471        is clear that when (*THEN) is backtracked onto, it goes to the "next
472        alternative in the innermost enclosing group".
473    
474    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
475        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
476        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
477        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
478        (*THEN).
479    
480    3.  If \s appeared in a character class, it removed the VT character from
481        the class, even if it had been included by some previous item, for example
482        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
483        of \s, but is part of the POSIX "space" class.)
484    
485    4.  A partial match never returns an empty string (because you can always
486        match an empty string at the end of the subject); however the checking for
487        an empty string was starting at the "start of match" point. This has been
488        changed to the "earliest inspected character" point, because the returned
489        data for a partial match starts at this character. This means that, for
490        example, /(?<=abc)def/ gives a partial match for the subject "abc"
491        (previously it gave "no match").
492    
493    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
494        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
495        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
496        has an implication that the given string is incomplete (because a partial
497        match is preferred over a full match). For this reason, these items now
498        give a partial match in this situation. [Aside: previously, the one case
499        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
500        match rather than a full match, which was wrong by the old rules, but is
501        now correct.]
502    
503    6.  There was a bug in the handling of #-introduced comments, recognized when
504        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
505        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
506        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
507        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
508        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
509        places in pcre_compile().
510    
511    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
512        comments when looking ahead for named forward references to subpatterns,
513        the only newline sequence it recognized was NL. It now handles newlines
514        according to the set newline convention.
515    
516    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
517        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
518        cater for a lack of strerror(). These oversights have been fixed.
519    
520    9.  Added --match-limit and --recursion-limit to pcregrep.
521    
522    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
523    
524    11. When the -o option was used, pcregrep was setting a return code of 1, even
525        when matches were found, and --line-buffered was not being honoured.
526    
527    12. Added an optional parentheses number to the -o and --only-matching options
528        of pcregrep.
529    
530    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
531        can match an empty string. The code to do it in pcretest and pcredemo
532        needed fixing:
533    
534        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
535            only one byte after an empty string match just before CRLF (this case
536            just got forgotten; "any" and "anycrlf" were OK).
537    
538        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
539            mode when an empty string match preceded an ASCII character followed by
540            a non-ASCII character. (The code for advancing by one character rather
541            than one byte was nonsense.)
542    
543        (c) The pcredemo.c sample program did not have any code at all to handle
544            the cases when CRLF is a valid newline sequence.
545    
546    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
547        as a starting offset was within the subject string. There is now a new
548        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
549        negative or greater than the length of the string. In order to test this,
550        pcretest is extended to allow the setting of negative starting offsets.
551    
552    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
553        starting offset points to the beginning of a UTF-8 character was
554        unnecessarily clumsy. I tidied it up.
555    
556    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
557        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
558    
559    17. Nobody had reported that the --include_dir option, which was added in
560        release 7.7 should have been called --include-dir (hyphen, not underscore)
561        for compatibility with GNU grep. I have changed it to --include-dir, but
562        left --include_dir as an undocumented synonym, and the same for
563        --exclude-dir, though that is not available in GNU grep, at least as of
564        release 2.5.4.
565    
566    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
567        characters from a string of bytes) have been redefined so as not to use
568        loops, in order to improve performance in some environments. At the same
569        time, I abstracted some of the common code into auxiliary macros to save
570        repetition (this should not affect the compiled code).
571    
572    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
573        compile-time error is now given if \c is not followed by an ASCII
574        character, that is, a byte less than 128. (In EBCDIC mode, the code is
575        different, and any byte value is allowed.)
576    
577    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
578        START_OPTIMIZE option, which is now allowed at compile time - but just
579        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
580        to pcregrep and other applications that have no direct access to PCRE
581        options. The new /Y option in pcretest sets this option when calling
582        pcre_compile().
583    
584    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
585        back references. Groups containing recursive back references were forced to
586        be atomic by that change, but in the case of named groups, the amount of
587        memory required was incorrectly computed, leading to "Failed: internal
588        error: code overflow". This has been fixed.
589    
590    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
591        pcretest.c, to avoid build problems in some Borland environments.
592    
593    
594    Version 8.10 25-Jun-2010
595    ------------------------
596    
597    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
598        THEN.
599    
600    2.  (*ACCEPT) was not working when inside an atomic group.
601    
602    3.  Inside a character class, \B is treated as a literal by default, but
603        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
604        causes the error). The code is unchanged, but I tidied the documentation.
605    
606    4.  Inside a character class, PCRE always treated \R and \X as literals,
607        whereas Perl faults them if its -w option is set. I have changed PCRE so
608        that it faults them when PCRE_EXTRA is set.
609    
610    5.  Added support for \N, which always matches any character other than
611        newline. (It is the same as "." when PCRE_DOTALL is not set.)
612    
613    6.  When compiling pcregrep with newer versions of gcc which may have
614        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
615        declared with attribute warn_unused_result" were given. Just casting the
616        result to (void) does not stop the warnings; a more elaborate fudge is
617        needed. I've used a macro to implement this.
618    
619    7.  Minor change to pcretest.c to avoid a compiler warning.
620    
621    8.  Added four artifical Unicode properties to help with an option to make
622        \s etc use properties (see next item). The new properties are: Xan
623        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
624    
625    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
626        use Unicode properties. (*UCP) at the start of a pattern can be used to set
627        this option. Modified pcretest to add /W to test this facility. Added
628        REG_UCP to make it available via the POSIX interface.
629    
630    10. Added --line-buffered to pcregrep.
631    
632    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
633        studied, and the match started with a letter with a code point greater than
634        127 whose first byte was different to the first byte of the other case of
635        the letter, the other case of this starting letter was not recognized
636        (#976).
637    
638    12. If a pattern that was studied started with a repeated Unicode property
639        test, for example, \p{Nd}+, there was the theoretical possibility of
640        setting up an incorrect bitmap of starting bytes, but fortunately it could
641        not have actually happened in practice until change 8 above was made (it
642        added property types that matched character-matching opcodes).
643    
644    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
645        possible starting bytes for non-anchored patterns.
646    
647    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
648        \R, and also a number of cases that involve Unicode properties, both
649        explicit and implicit when PCRE_UCP is set.
650    
651    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
652        input, it could crash or give wrong results if characters with values
653        greater than 0xc0 were present in the subject string. (Detail: it assumed
654        UTF-8 input when processing these items.)
655    
656    16. Added a lot of (int) casts to avoid compiler warnings in systems where
657        size_t is 64-bit (#991).
658    
659    17. Added a check for running out of memory when PCRE is compiled with
660        --disable-stack-for-recursion (#990).
661    
662    18. If the last data line in a file for pcretest does not have a newline on
663        the end, a newline was missing in the output.
664    
665    19. The default pcre_chartables.c file recognizes only ASCII characters (values
666        less than 128) in its various bitmaps. However, there is a facility for
667        generating tables according to the current locale when PCRE is compiled. It
668        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
669        characters, are recognized by isspace() and therefore were getting set in
670        these tables, and indeed these tables seem to approximate to ISO 8859. This
671        caused a problem in UTF-8 mode when pcre_study() was used to create a list
672        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
673        which of course cannot start UTF-8 characters. I have changed the code so
674        that only real ASCII characters (less than 128) and the correct starting
675        bytes for UTF-8 encodings are set for characters greater than 127 when in
676        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
677        altogether.)
678    
679    20. Added the /T option to pcretest so as to be able to run tests with non-
680        standard character tables, thus making it possible to include the tests
681        used for 19 above in the standard set of tests.
682    
683    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
684        reference to a subpattern the other side of a comment that contains an
685        opening parenthesis caused either an internal compiling error, or a
686        reference to the wrong subpattern.
687    
688    
689    Version 8.02 19-Mar-2010
690    ------------------------
691    
692    1.  The Unicode data tables have been updated to Unicode 5.2.0.
693    
694    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
695        configured.
696    
697    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
698        original author of that file, following a query about its status.
699    
700    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
701        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
702    
703    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
704        quantifier applied to a forward-referencing subroutine call, could compile
705        incorrect code or give the error "internal error: previously-checked
706        referenced subpattern not found".
707    
708    6.  Both MS Visual Studio and Symbian OS have problems with initializing
709        variables to point to external functions. For these systems, therefore,
710        pcre_malloc etc. are now initialized to local functions that call the
711        relevant global functions.
712    
713    7.  There were two entries missing in the vectors called coptable and poptable
714        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
715        I've fixed the data, and added a kludgy way of testing at compile time that
716        the lengths are correct (equal to the number of opcodes).
717    
718    8.  Following on from 7, I added a similar kludge to check the length of the
719        eint vector in pcreposix.c.
720    
721    9.  Error texts for pcre_compile() are held as one long string to avoid too
722        much relocation at load time. To find a text, the string is searched,
723        counting zeros. There was no check for running off the end of the string,
724        which could happen if a new error number was added without updating the
725        string.
726    
727    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
728    
729    11. \K was not working if it appeared in an atomic group or in a group that
730        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
731        \K is "not well defined" if used in an assertion. PCRE now accepts it if
732        the assertion is positive, but not if it is negative.
733    
734    12. Change 11 fortuitously reduced the size of the stack frame used in the
735        "match()" function of pcre_exec.c by one pointer. Forthcoming
736        implementation of support for (*MARK) will need an extra pointer on the
737        stack; I have reserved it now, so that the stack frame size does not
738        decrease.
739    
740    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
741        item in branch that calls a recursion is a subroutine call - as in the
742        second branch in the above example - was incorrectly given the compile-
743        time error "recursive call could loop indefinitely" because pcre_compile()
744        was not correctly checking the subroutine for matching a non-empty string.
745    
746    14. The checks for overrunning compiling workspace could trigger after an
747        overrun had occurred. This is a "should never occur" error, but it can be
748        triggered by pathological patterns such as hundreds of nested parentheses.
749        The checks now trigger 100 bytes before the end of the workspace.
750    
751    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
752    
753    
754    Version 8.01 19-Jan-2010
755    ------------------------
756    
757    1.  If a pattern contained a conditional subpattern with only one branch (in
758        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
759        computed the wrong minimum data length (which is of course zero for such
760        subpatterns). This could cause incorrect "no match" results.
761    
762    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
763        the pattern is reset in the first branch, pcre_compile() failed with
764        "internal error: code overflow at offset...". This happened only when
765        the reset was to the original external option setting. (An optimization
766        abstracts leading options settings into an external setting, which was the
767        cause of this.)
768    
769    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
770        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
771        assertion pattern did not match (meaning that the assertion was true), it
772        was incorrectly treated as false if the SKIP had been reached during the
773        matching. This also applied to assertions used as conditions.
774    
775    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
776        assertion subpattern, including such a pattern used as a condition,
777        unpredictable results occurred, instead of the error return
778        PCRE_ERROR_DFA_UITEM.
779    
780    5.  The C++ GlobalReplace function was not working like Perl for the special
781        situation when an empty string is matched. It now does the fancy magic
782        stuff that is necessary.
783    
784    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
785        removed. (These were left over from very, very early versions of PCRE.)
786    
787    7.  Some cosmetic changes to the code to make life easier when compiling it
788        as part of something else:
789    
790        (a) Change DEBUG to PCRE_DEBUG.
791    
792        (b) In pcre_compile(), rename the member of the "branch_chain" structure
793            called "current" as "current_branch", to prevent a collision with the
794            Linux macro when compiled as a kernel module.
795    
796        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
797            prevent a collision with the Linux macro when compiled as a kernel
798            module.
799    
800    8.  In pcre_compile() there are some checks for integer overflows that used to
801        cast potentially large values to (double). This has been changed to that
802        when building, a check for int64_t is made, and if it is found, it is used
803        instead, thus avoiding the use of floating point arithmetic. (There is no
804        other use of FP in PCRE.) If int64_t is not found, the fallback is to
805        double.
806    
807    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
808        2005 (difference between two addresses compared to an unsigned value).
809    
810    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
811        custom one, because of the following reported problem in Windows:
812    
813          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
814              under Win32.
815          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
816              therefore missing the function definition.
817          - The compiler thus generates a "C" signature for the test function.
818          - The linker fails to find the "C" function.
819          - PCRE fails to configure if asked to do so against libbz2.
820    
821    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
822        messages were output:
823    
824          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
825          rerunning libtoolize, to keep the correct libtool macros in-tree.
826          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
827    
828        I have done both of these things.
829    
830    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
831        most of the time, it *can* run out if it is given a pattern that contains a
832        runaway infinite recursion. I updated the discussion in the pcrestack man
833        page.
834    
835    13. Now that we have gone to the x.xx style of version numbers, the minor
836        version may start with zero. Using 08 or 09 is a bad idea because users
837        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
838        interpreted as invalid octal numbers. I've updated the previous comment in
839        configure.ac, and also added a check that gives an error if 08 or 09 are
840        used.
841    
842    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
843        causing partial matching to fail when the end of the subject matched \W
844        in a UTF-8 pattern where \W was quantified with a minimum of 3.
845    
846    15. There were some discrepancies between the declarations in pcre_internal.h
847        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
848        their definitions. The declarations used "const uschar *" and the
849        definitions used USPTR. Even though USPTR is normally defined as "const
850        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
851        reported that: "This difference in casting confuses some C++ compilers, for
852        example, SunCC recognizes above declarations as different functions and
853        generates broken code for hbpcre." I have changed the declarations to use
854        USPTR.
855    
856    16. GNU libtool is named differently on some systems. The autogen.sh script now
857        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
858        (FreeBSD).
859    
860    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
861        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
862        comment: "Figure out how to create a longlong from a string: strtoll and
863        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
864        instance, but it only takes 2 args instead of 3!"
865    
866    18. A subtle bug concerned with back references has been fixed by a change of
867        specification, with a corresponding code fix. A pattern such as
868        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
869        refers, was giving matches when it shouldn't. For example, xa=xaaa would
870        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
871        same bug. Such groups have to be quantified to be useful, or contained
872        inside another quantified group. (If there's no repetition, the reference
873        can never match.) The problem arises because, having left the group and
874        moved on to the rest of the pattern, a later failure that backtracks into
875        the group uses the captured value from the final iteration of the group
876        rather than the correct earlier one. I have fixed this in PCRE by forcing
877        any group that contains a reference to itself to be an atomic group; that
878        is, there cannot be any backtracking into it once it has completed. This is
879        similar to recursive and subroutine calls.
880    
881    
882    Version 8.00 19-Oct-09
883    ----------------------
884    
885    1.  The table for translating pcre_compile() error codes into POSIX error codes
886        was out-of-date, and there was no check on the pcre_compile() error code
887        being within the table. This could lead to an OK return being given in
888        error.
889    
890    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
891        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
892        in a Windows environment.
893    
894    3.  The pcregrep --count option prints the count for each file even when it is
895        zero, as does GNU grep. However, pcregrep was also printing all files when
896        --files-with-matches was added. Now, when both options are given, it prints
897        counts only for those files that have at least one match. (GNU grep just
898        prints the file name in this circumstance, but including the count seems
899        more useful - otherwise, why use --count?) Also ensured that the
900        combination -clh just lists non-zero counts, with no names.
901    
902    4.  The long form of the pcregrep -F option was incorrectly implemented as
903        --fixed_strings instead of --fixed-strings. This is an incompatible change,
904        but it seems right to fix it, and I didn't think it was worth preserving
905        the old behaviour.
906    
907    5.  The command line items --regex=pattern and --regexp=pattern were not
908        recognized by pcregrep, which required --regex pattern or --regexp pattern
909        (with a space rather than an '='). The man page documented the '=' forms,
910        which are compatible with GNU grep; these now work.
911    
912    6.  No libpcreposix.pc file was created for pkg-config; there was just
913        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
914    
915    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
916        when UCP support is not needed, by modifying the Python script that
917        generates it from Unicode data files. This should not matter if the module
918        is correctly used as a library, but I received one complaint about 50K of
919        unwanted data. My guess is that the person linked everything into his
920        program rather than using a library. Anyway, it does no harm.
921    
922    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
923        was a minimum greater than 1 for a wide character in a possessive
924        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
925        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
926        character. Chaos in the form of incorrect output or a compiling loop could
927        result.
928    
929    9.  The restrictions on what a pattern can contain when partial matching is
930        requested for pcre_exec() have been removed. All patterns can now be
931        partially matched by this function. In addition, if there are at least two
932        slots in the offset vector, the offset of the earliest inspected character
933        for the match and the offset of the end of the subject are set in them when
934        PCRE_ERROR_PARTIAL is returned.
935    
936    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
937        synonymous with PCRE_PARTIAL, for backwards compatibility, and
938        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
939        and may be more useful for multi-segment matching.
940    
941    11. Partial matching with pcre_exec() is now more intuitive. A partial match
942        used to be given if ever the end of the subject was reached; now it is
943        given only if matching could not proceed because another character was
944        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
945        string "Z", which now yields "no match" instead of "partial match". In the
946        case of pcre_dfa_exec(), "no match" is given if every matching path for the
947        final character ended with (*FAIL).
948    
949    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
950        if the pattern had a "must contain" character that was already found in the
951        earlier partial match, unless partial matching was again requested. For
952        example, with the pattern /dog.(body)?/, the "must contain" character is
953        "g". If the first part-match was for the string "dog", restarting with
954        "sbody" failed. This bug has been fixed.
955    
956    13. The string returned by pcre_dfa_exec() after a partial match has been
957        changed so that it starts at the first inspected character rather than the
958        first character of the match. This makes a difference only if the pattern
959        starts with a lookbehind assertion or \b or \B (\K is not supported by
960        pcre_dfa_exec()). It's an incompatible change, but it makes the two
961        matching functions compatible, and I think it's the right thing to do.
962    
963    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
964        so that the demonstration program is easily available in environments where
965        PCRE has not been installed from source.
966    
967    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
968        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
969        library.
970    
971    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
972        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
973        is not the first non-POSIX option to be added. Clearly some people find
974        these options useful.
975    
976    17. If a caller to the POSIX matching function regexec() passes a non-zero
977        value for nmatch with a NULL value for pmatch, the value of
978        nmatch is forced to zero.
979    
980    18. RunGrepTest did not have a test for the availability of the -u option of
981        the diff command, as RunTest does. It now checks in the same way as
982        RunTest, and also checks for the -b option.
983    
984    19. If an odd number of negated classes containing just a single character
985        interposed, within parentheses, between a forward reference to a named
986        subpattern and the definition of the subpattern, compilation crashed with
987        an internal error, complaining that it could not find the referenced
988        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
989        [The bug was that it was starting one character too far in when skipping
990        over the character class, thus treating the ] as data rather than
991        terminating the class. This meant it could skip too much.]
992    
993    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
994        /g option in pcretest when the pattern contains \K, which makes it possible
995        to have an empty string match not at the start, even when the pattern is
996        anchored. Updated pcretest and pcredemo to use this option.
997    
998    21. If the maximum number of capturing subpatterns in a recursion was greater
999        than the maximum at the outer level, the higher number was returned, but
1000        with unset values at the outer level. The correct (outer level) value is
1001        now given.
1002    
1003    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1004        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1005        make it do so. The string so far is captured, making this feature
1006        compatible with Perl.
1007    
1008    23. The tests have been re-organized, adding tests 11 and 12, to make it
1009        possible to check the Perl 5.10 features against Perl 5.10.
1010    
1011    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1012        pattern matches a fixed length string. PCRE did not allow this; now it
1013        does. Neither allows recursion.
1014    
1015    25. I finally figured out how to implement a request to provide the minimum
1016        length of subject string that was needed in order to match a given pattern.
1017        (It was back references and recursion that I had previously got hung up
1018        on.) This code has now been added to pcre_study(); it finds a lower bound
1019        to the length of subject needed. It is not necessarily the greatest lower
1020        bound, but using it to avoid searching strings that are too short does give
1021        some useful speed-ups. The value is available to calling programs via
1022        pcre_fullinfo().
1023    
1024    26. While implementing 25, I discovered to my embarrassment that pcretest had
1025        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1026        study optimizations had never been tested with that matching function.
1027        Oops. What is worse, even when it was passed study data, there was a bug in
1028        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1029        were also very few tests of studied patterns with pcre_dfa_exec().
1030    
1031    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1032        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1033        on the other side of the coin, they are no longer allowed to have different
1034        names, because these cannot be distinguished in PCRE, and this has caused
1035        confusion. (This is a difference from Perl.)
1036    
1037    28. When duplicate subpattern names are present (necessarily with different
1038        numbers, as required by 27 above), and a test is made by name in a
1039        conditional pattern, either for a subpattern having been matched, or for
1040        recursion in such a pattern, all the associated numbered subpatterns are
1041        tested, and the overall condition is true if the condition is true for any
1042        one of them. This is the way Perl works, and is also more like the way
1043        testing by number works.
1044    
1045    
1046    Version 7.9 11-Apr-09
1047    ---------------------
1048    
1049    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1050        (pcretest), all targets were linked against these libraries. This included
1051        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1052        libraries. This caused unwanted dependencies to be created. This problem
1053        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1054        pcretest is linked with readline.
1055    
1056    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1057        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1058        moved outside it again, because FALSE and TRUE are already defined in AIX,
1059        but BOOL is not.
1060    
1061    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1062        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1063    
1064    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1065        hyphens) following file names and line numbers when outputting matching
1066        lines. This is not true; no spaces are inserted. I have also clarified the
1067        wording for the --colour (or --color) option.
1068    
1069    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1070        was not coloured; this is different to GNU grep, so I have changed it to be
1071        the same.
1072    
1073    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1074        each matching line was coloured. Now it goes on to look for further matches
1075        of any of the test patterns, which is the same behaviour as GNU grep.
1076    
1077    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1078        doesn't make sense to accept an empty string match in pcregrep, so I have
1079        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1080        seems to be how GNU grep behaves.
1081    
1082    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1083        start or after a newline", because the conditional assertion was not being
1084        correctly handled. The rule now is that both the assertion and what follows
1085        in the first alternative must satisfy the test.
1086    
1087    9.  If auto-callout was enabled in a pattern with a conditional group whose
1088        condition was an assertion, PCRE could crash during matching, both with
1089        pcre_exec() and pcre_dfa_exec().
1090    
1091    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1092        used for matching.
1093    
1094    11. Unicode property support in character classes was not working for
1095        characters (bytes) greater than 127 when not in UTF-8 mode.
1096    
1097    12. Added the -M command line option to pcretest.
1098    
1099    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1100    
1101    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1102    
1103    16. Added comments and documentation about mis-use of no_arg in the C++
1104        wrapper.
1105    
1106    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1107        from Martin Jerabek that uses macro names for all relevant character and
1108        string constants.
1109    
1110    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1111        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1112        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1113        these, but not everybody uses configure.
1114    
1115    19. A conditional group that had only one branch was not being correctly
1116        recognized as an item that could match an empty string. This meant that an
1117        enclosing group might also not be so recognized, causing infinite looping
1118        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1119        with the subject "ab", where knowledge that the repeated group can match
1120        nothing is needed in order to break the loop.
1121    
1122    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1123        exec(), but without supplying a callout function, matching went wrong.
1124    
1125    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1126        leak if the size of the offset vector was greater than 30. When the vector
1127        is smaller, the saved offsets during recursion go onto a local stack
1128        vector, but for larger vectors malloc() is used. It was failing to free
1129        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1130        error, in fact).
1131    
1132    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1133        heapframe that is used only when UTF-8 support is enabled. This caused no
1134        problem, but was untidy.
1135    
1136    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1137        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1138        included within another project.
1139    
1140    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1141        slightly modified by me:
1142    
1143          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1144              not building pcregrep.
1145    
1146          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1147              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1148    
1149    25. Forward references, both numeric and by name, in patterns that made use of
1150        duplicate group numbers, could behave incorrectly or give incorrect errors,
1151        because when scanning forward to find the reference group, PCRE was not
1152        taking into account the duplicate group numbers. A pattern such as
1153        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1154    
1155    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1156        the feature of a custom pointer more persuasive (as requested by a user).
1157    
1158    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1159        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1160        pre-defined.
1161    
1162    28. Added support for (*UTF8) at the start of a pattern.
1163    
1164    29. Arrange for flags added by the "release type" setting in CMake to be shown
1165        in the configuration summary.
1166    
1167    
1168    Version 7.8 05-Sep-08
1169    ---------------------
1170    
1171    1.  Replaced UCP searching code with optimized version as implemented for Ad
1172        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1173        stage table and inline lookup instead of a function, giving speed ups of 2
1174        to 5 times on some simple patterns that I tested. Permission was given to
1175        distribute the MultiStage2.py script that generates the tables (it's not in
1176        the tarball, but is in the Subversion repository).
1177    
1178    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1179        scripts.
1180    
1181    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1182        a group with a zero qualifier. The result of the study could be incorrect,
1183        or the function might crash, depending on the pattern.
1184    
1185    4.  Caseless matching was not working for non-ASCII characters in back
1186        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1187        It now works when Unicode Property Support is available.
1188    
1189    5.  In pcretest, an escape such as \x{de} in the data was always generating
1190        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1191        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1192        truncation.
1193    
1194    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1195    
1196    7.  Added two (int) casts to pcregrep when printing the difference of two
1197        pointers, in case they are 64-bit values.
1198    
1199    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1200        test 2 if it fails.
1201    
1202    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1203        and a #define of that name to empty if it is not externally set. This is to
1204        allow users of MSVC to set it if necessary.
1205    
1206    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1207        the convenience functions in the pcre_get.c source file.
1208    
1209    11. An option change at the start of a pattern that had top-level alternatives
1210        could cause overwriting and/or a crash. This command provoked a crash in
1211        some environments:
1212    
1213          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1214    
1215        This potential security problem was recorded as CVE-2008-2371.
1216    
1217    12. For a pattern where the match had to start at the beginning or immediately
1218        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1219        pcre_dfa_exec() could read past the end of the passed subject if there was
1220        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1221        pcretest so that it places the subject at the end of its malloc-ed buffer.
1222    
1223    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1224        exec() might read past the end of the data buffer in UTF-8 mode.
1225    
1226    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1227        the data contained the byte 0x85 as part of a UTF-8 character within its
1228        first line. This applied both to normal and DFA matching.
1229    
1230    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1231        /^[^d]*?$/8 failed to match "abc".
1232    
1233    16. Added a missing copyright notice to pcrecpp_internal.h.
1234    
1235    17. Make it more clear in the documentation that values returned from
1236        pcre_exec() in ovector are byte offsets, not character counts.
1237    
1238    18. Tidied a few places to stop certain compilers from issuing warnings.
1239    
1240    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1241        supplied by Stefan Weber. I made a further small update for 7.8 because
1242        there is a change of source arrangements: the pcre_searchfuncs.c module is
1243        replaced by pcre_ucd.c.
1244    
1245    
1246    Version 7.7 07-May-08
1247    ---------------------
1248    
1249    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1250        a string to a long long, pretend we don't even have a long long." This is
1251        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1252    
1253    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1254        pre-7.6 versions, which defined a global no_arg variable instead of putting
1255        it in the RE class. (See also #8 below.)
1256    
1257    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1258        Lopes.
1259    
1260    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1261    
1262        (1) The include/exclude patterns were being applied to the whole pathnames
1263            of files, instead of just to the final components.
1264    
1265        (2) If there was more than one level of directory, the subdirectories were
1266            skipped unless they satisfied the include/exclude conditions. This is
1267            inconsistent with GNU grep (and could even be seen as contrary to the
1268            pcregrep specification - which I improved to make it absolutely clear).
1269            The action now is always to scan all levels of directory, and just
1270            apply the include/exclude patterns to regular files.
1271    
1272    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1273        --exclude_dir in the tests to avoid scanning .svn directories.
1274    
1275    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1276        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1277        doesn't support NULs in patterns.
1278    
1279    7.  Added some missing "const"s to declarations of static tables in
1280        pcre_compile.c and pcre_dfa_exec.c.
1281    
1282    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1283        caused by fix #2  above. (Subsequently also a second patch to fix the
1284        first patch. And a third patch - this was a messy problem.)
1285    
1286    9.  Applied Craig's patch to remove the use of push_back().
1287    
1288    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1289        matching function regexec().
1290    
1291    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1292        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1293        references. PCRE supports relative numbers with this syntax (I don't think
1294        Oniguruma does).
1295    
1296    12. Previously, a group with a zero repeat such as (...){0} was completely
1297        omitted from the compiled regex. However, this means that if the group
1298        was called as a subroutine from elsewhere in the pattern, things went wrong
1299        (an internal error was given). Such groups are now left in the compiled
1300        pattern, with a new opcode that causes them to be skipped at execution
1301        time.
1302    
1303    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1304        to the way PCRE behaves:
1305    
1306        (a) A lone ] character is dis-allowed (Perl treats it as data).
1307    
1308        (b) A back reference to an unmatched subpattern matches an empty string
1309            (Perl fails the current match path).
1310    
1311        (c) A data ] in a character class must be notated as \] because if the
1312            first data character in a class is ], it defines an empty class. (In
1313            Perl it is not possible to have an empty class.) The empty class []
1314            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1315            The negative empty class [^] matches any one character, independently
1316            of the DOTALL setting.
1317    
1318    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1319        non-existent subpattern following a character class starting with ']' and
1320        containing () gave an internal compiling error instead of "reference to
1321        non-existent subpattern". Fortunately, when the pattern did exist, the
1322        compiled code was correct. (When scanning forwards to check for the
1323        existencd of the subpattern, it was treating the data ']' as terminating
1324        the class, so got the count wrong. When actually compiling, the reference
1325        was subsequently set up correctly.)
1326    
1327    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1328        it was being rejected as not supported by pcre_dfa_exec(), even though
1329        other assertions are supported. I have made pcre_dfa_exec() support
1330        (*FAIL).
1331    
1332    16. The implementation of 13c above involved the invention of a new opcode,
1333        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1334        cannot be changed at match time, I realized I could make a small
1335        improvement to matching performance by compiling OP_ALLANY instead of
1336        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1337        on the OP_ANY path.
1338    
1339    17. Compiling pcretest on Windows with readline support failed without the
1340        following two fixes: (1) Make the unistd.h include conditional on
1341        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1342    
1343    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1344        ncurses library to be included for pcretest when ReadLine support is
1345        requested, but also to allow for it to be overridden. This patch came from
1346        Daniel Bergström.
1347    
1348    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1349        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1350        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1351        spotting this.
1352    
1353    
1354    Version 7.6 28-Jan-08
1355    ---------------------
1356    
1357    1.  A character class containing a very large number of characters with
1358        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1359        overflow.
1360    
1361    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1362        HAVE_LONG_LONG is not defined.
1363    
1364    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1365        bring them up to date and include new features. This patch includes:
1366    
1367        - Fixed PH's badly added libz and libbz2 support.
1368        - Fixed a problem with static linking.
1369        - Added pcredemo. [But later removed - see 7 below.]
1370        - Fixed dftables problem and added an option.
1371        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1372            HAVE_LONG_LONG.
1373        - Added readline support for pcretest.
1374        - Added an listing of the option settings after cmake has run.
1375    
1376    4.  A user submitted a patch to Makefile that makes it easy to create
1377        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1378        Makefile.am that cause it to include this special target, without
1379        affecting anything else. Note that the same mingw target plus all
1380        the other distribution libraries and programs are now supported
1381        when configuring with CMake (see 6 below) instead of with
1382        Configure/Make.
1383    
1384    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1385        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1386        exported in the Windows port". It has not yet been confirmed that the patch
1387        solves the problem, but it does no harm.
1388    
1389    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1390        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1391        with CMake, and also correct the comment about stack recursion.
1392    
1393    7.  Remove the automatic building of pcredemo from the ./configure system and
1394        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1395        of a program that users should build themselves after PCRE is installed, so
1396        building it automatically is not really right. What is more, it gave
1397        trouble in some build environments.
1398    
1399    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1400    
1401    
1402    Version 7.5 10-Jan-08
1403    ---------------------
1404    
1405    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1406        values in parens when parsing an RE using the C++ wrapper."
1407    
1408    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1409        Characters greater than 255 were excluded from the class instead of being
1410        included.
1411    
1412    3.  The same bug as (2) above applied to negated POSIX classes such as
1413        [:^space:].
1414    
1415    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1416        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1417        I have changed it.
1418    
1419    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1420        first named subpattern) and a construct such as (?&a) would reference the
1421        first named subpattern whose name started with "a" (in other words, the
1422        length check was missing). Both these problems are fixed. "Subpattern name
1423        expected" is now given for (?&) (a zero-length name), and this patch also
1424        makes it give the same error for \k'' (previously it complained that that
1425        was a reference to a non-existent subpattern).
1426    
1427    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1428        this is right because (?- can be followed by option settings as well as by
1429        digits. I have, however, made the messages clearer.
1430    
1431    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1432        than the number used in the conditional) now cause a compile-time error.
1433        This is actually not compatible with Perl, which accepts such patterns, but
1434        treats the conditional as always being FALSE (as PCRE used to), but it
1435        seems to me that giving a diagnostic is better.
1436    
1437    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1438        and messages.
1439    
1440    9.  Fix two occurrences of "backslash" in comments that should have been
1441        "backspace".
1442    
1443    10. Remove two redundant lines of code that can never be obeyed (their function
1444        was moved elsewhere).
1445    
1446    11. The program that makes PCRE's Unicode character property table had a bug
1447        which caused it to generate incorrect table entries for sequences of
1448        characters that have the same character type, but are in different scripts.
1449        It amalgamated them into a single range, with the script of the first of
1450        them. In other words, some characters were in the wrong script. There were
1451        thirteen such cases, affecting characters in the following ranges:
1452    
1453          U+002b0 - U+002c1
1454          U+0060c - U+0060d
1455          U+0061e - U+00612
1456          U+0064b - U+0065e
1457          U+0074d - U+0076d
1458          U+01800 - U+01805
1459          U+01d00 - U+01d77
1460          U+01d9b - U+01dbf
1461          U+0200b - U+0200f
1462          U+030fc - U+030fe
1463          U+03260 - U+0327f
1464          U+0fb46 - U+0fbb1
1465          U+10450 - U+1049d
1466    
1467    12. The -o option (show only the matching part of a line) for pcregrep was not
1468        compatible with GNU grep in that, if there was more than one match in a
1469        line, it showed only the first of them. It now behaves in the same way as
1470        GNU grep.
1471    
1472    13. If the -o and -v options were combined for pcregrep, it printed a blank
1473        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1474        does the same. The return code can be used to tell if there were any
1475        non-matching lines.
1476    
1477    14. Added --file-offsets and --line-offsets to pcregrep.
1478    
1479    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1480        infinitely looping recursion. The bug was that positive lookaheads were not
1481        being skipped when checking for a possible empty match (negative lookaheads
1482        and both kinds of lookbehind were skipped).
1483    
1484    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1485        inclusion of <windows.h> to before rather than after the definition of
1486        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1487    
1488    17. Specifying a possessive quantifier with a specific limit for a Unicode
1489        character property caused pcre_compile() to compile bad code, which led at
1490        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1491        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1492        caused the error; without that there was no problem.
1493    
1494    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1495    
1496    19. Added --enable-pcretest-libreadline.
1497    
1498    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1499        RE::GlobalReplace(). As a result, the number of replacements returned was
1500        double what it should be. I removed one of the increments, but Craig sent a
1501        later patch that removed the other one (the right fix) and added unit tests
1502        that check the return values (which was not done before).
1503    
1504    21. Several CMake things:
1505    
1506        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1507            the names libpcre and libpcreposix, not just pcre and pcreposix.
1508    
1509        (2) The above change means that pcretest and pcregrep are now correctly
1510            linked with the newly-built libraries, not previously installed ones.
1511    
1512        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1513    
1514    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1515        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1516        UTF-8 newline character). The key issue is that the pattern starts .*;
1517        this means that the match must be either at the beginning, or after a
1518        newline. The bug was in the code for advancing after a failed match and
1519        checking that the new position followed a newline. It was not taking
1520        account of UTF-8 characters correctly.
1521    
1522    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1523        character classes. PCRE was not treating the sequence [:...:] as a
1524        character class unless the ... were all letters. Perl, however, seems to
1525        allow any characters between [: and :], though of course it rejects as
1526        unknown any "names" that contain non-letters, because all the known class
1527        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1528        for example, whereas PCRE did not - it did not recognize a POSIX character
1529        class. This seemed a bit dangerous, so the code has been changed to be
1530        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1531        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1532        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1533        Perl does, and where it didn't before.
1534    
1535    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1536        Windows environments %n is disabled by default.
1537    
1538    
1539    Version 7.4 21-Sep-07
1540    ---------------------
1541    
1542    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1543        means that a class such as [\s] counted as "explicit reference to CR or
1544        LF". That isn't really right - the whole point of the change was to try to
1545        help when there was an actual mention of one of the two characters. So now
1546        the change happens only if \r or \n (or a literal CR or LF) character is
1547        encountered.
1548    
1549    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1550        of both had grown to the point where there were only 3 bits left.
1551        Fortunately, there was spare space in the data structure, and so I have
1552        moved the internal flags into a new 16-bit field to free up more option
1553        bits.
1554    
1555    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1556        but did not set the internal JCHANGED flag - either of these is enough to
1557        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1558        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1559        start sets both bits.
1560    
1561    4.  Added options (at build time, compile time, exec time) to change \R from
1562        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1563    
1564    5.  doc/pcresyntax.html was missing from the distribution.
1565    
1566    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1567        compatibility, even though it is no longer used.
1568    
1569    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1570        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1571        windows.h file is present (where different names are used). [This was
1572        reversed later after testing - see 16 below.]
1573    
1574    8.  Changed all #include <config.h> to #include "config.h". There were also
1575        some further <pcre.h> cases that I changed to "pcre.h".
1576    
1577    9.  When pcregrep was used with the --colour option, it missed the line ending
1578        sequence off the lines that it output.
1579    
1580    10. It was pointed out to me that arrays of string pointers cause lots of
1581        relocations when a shared library is dynamically loaded. A technique of
1582        using a single long string with a table of offsets can drastically reduce
1583        these. I have refactored PCRE in four places to do this. The result is
1584        dramatic:
1585    
1586          Originally:                          290
1587          After changing UCP table:            187
1588          After changing error message table:   43
1589          After changing table of "verbs"       36
1590          After changing table of Posix names   22
1591    
1592        Thanks to the folks working on Gregex for glib for this insight.
1593    
1594    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1595        unicode-properties was also set.
1596    
1597    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1598    
1599    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1600        checked only for CRLF.
1601    
1602    14. Added casts to pcretest.c to avoid compiler warnings.
1603    
1604    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1605    
1606    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1607        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1608        entirely. This removes changes made in 7 above.
1609    
1610    17. The CMake files have been updated, and there is now more information about
1611        building with CMake in the NON-UNIX-USE document.
1612    
1613    
1614    Version 7.3 28-Aug-07
1615    ---------------------
1616    
1617     1. In the rejigging of the build system that eventually resulted in 7.1, the
1618        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1619        brackets there is not right, since it causes compilers to look for an
1620        installed pcre.h, not the version that is in the source that is being
1621        compiled (which of course may be different). I have changed it back to:
1622    
1623          #include "pcre.h"
1624    
1625        I have a vague recollection that the change was concerned with compiling in
1626        different directories, but in the new build system, that is taken care of
1627        by the VPATH setting the Makefile.
1628    
1629     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1630        when the subject happened to end in the byte 0x85 (e.g. if the last
1631        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1632        characters but of course it shouldn't be taken as a newline when it is part
1633        of another character. The bug was that, for an unlimited repeat of . in
1634        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1635        characters when looking for a newline.
1636    
1637     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1638    
1639     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1640        in debug output.
1641    
1642     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1643        long printing in the pcrecpp unittest when running under MinGW.
1644    
1645     6. ESC_K was left out of the EBCDIC table.
1646    
1647     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1648        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1649        limit also applies to "virtual nesting" when a pattern is recursive, and in
1650        this case 1000 isn't so big. I have been able to remove this limit at the
1651        expense of backing off one optimization in certain circumstances. Normally,
1652        when pcre_exec() would call its internal match() function recursively and
1653        immediately return the result unconditionally, it uses a "tail recursion"
1654        feature to save stack. However, when a subpattern that can match an empty
1655        string has an unlimited repetition quantifier, it no longer makes this
1656        optimization. That gives it a stack frame in which to save the data for
1657        checking that an empty string has been matched. Previously this was taken
1658        from the 1000-entry workspace that had been reserved. So now there is no
1659        explicit limit, but more stack is used.
1660    
1661     8. Applied Daniel's patches to solve problems with the import/export magic
1662        syntax that is required for Windows, and which was going wrong for the
1663        pcreposix and pcrecpp parts of the library. These were overlooked when this
1664        problem was solved for the main library.
1665    
1666     9. There were some crude static tests to avoid integer overflow when computing
1667        the size of patterns that contain repeated groups with explicit upper
1668        limits. As the maximum quantifier is 65535, the maximum group length was
1669        set at 30,000 so that the product of these two numbers did not overflow a
1670        32-bit integer. However, it turns out that people want to use groups that
1671        are longer than 30,000 bytes (though not repeat them that many times).
1672        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1673        made it possible to implement the integer overflow checks in a much more
1674        dynamic way, which I have now done. The artificial limitation on group
1675        length has been removed - we now have only the limit on the total length of
1676        the compiled pattern, which depends on the LINK_SIZE setting.
1677    
1678    10. Fixed a bug in the documentation for get/copy named substring when
1679        duplicate names are permitted. If none of the named substrings are set, the
1680        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1681        empty string.
1682    
1683    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1684        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1685        because the ] is interpreted as the first data character and the
1686        terminating ] is not found. PCRE has been made compatible with Perl in this
1687        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1688        cause memory overwriting.
1689    
1690    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1691        string has been matched (to stop an infinite loop). It was not recognizing
1692        a conditional subpattern that could match an empty string if that
1693        subpattern was within another subpattern. For example, it looped when
1694        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1695        condition was not nested. This bug has been fixed.
1696    
1697    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1698        past the start of the subject in the presence of bytes with the top bit
1699        set, for example "\x8aBCD".
1700    
1701    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1702        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1703    
1704    14. Optimized (?!) to (*FAIL).
1705    
1706    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1707        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1708        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1709        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1710        does: it's just the validity check that is more restrictive.
1711    
1712    16. Inserted checks for integer overflows during escape sequence (backslash)
1713        processing, and also fixed erroneous offset values for syntax errors during
1714        backslash processing.
1715    
1716    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1717        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1718    
1719    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1720        caused an overrun.
1721    
1722    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1723        something other than just ASCII characters) inside a group that had an
1724        unlimited repeat caused a loop at compile time (while checking to see
1725        whether the group could match an empty string).
1726    
1727    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1728        [\P{Any}] did so. (Error in the code for printing property names.)
1729    
1730    21. An orphan \E inside a character class could cause a crash.
1731    
1732    22. A repeated capturing bracket such as (A)? could cause a wild memory
1733        reference during compilation.
1734    
1735    23. There are several functions in pcre_compile() that scan along a compiled
1736        expression for various reasons (e.g. to see if it's fixed length for look
1737        behind). There were bugs in these functions when a repeated \p or \P was
1738        present in the pattern. These operators have additional parameters compared
1739        with \d, etc, and these were not being taken into account when moving along
1740        the compiled data. Specifically:
1741    
1742        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1743            length.
1744    
1745        (b) An item such as \pL+ within a repeated group could cause crashes or
1746            loops.
1747    
1748        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1749            "reference to non-existent subpattern" error.
1750    
1751        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1752    
1753    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1754        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1755    
1756    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1757    
1758    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1759        character were causing crashes (broken optimization).
1760    
1761    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1762        \p or \P) caused a compile-time loop.
1763    
1764    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1765        break. For example, the unstudied pattern [\r\n]A does not match the string
1766        "\r\nA" because change 7.0/46 below moves the current point on by two
1767        characters after failing to match at the start. However, the pattern \nA
1768        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1769        the same is true. There doesn't seem any very clean way out of this, but
1770        what I have chosen to do makes the common cases work: PCRE now takes note
1771        of whether there can be an explicit match for \r or \n anywhere in the
1772        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1773        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1774        pattern has explicit CR or LF references.
1775    
1776    29. Added (*CR) etc for changing newline setting at start of pattern.
1777    
1778    
1779    Version 7.2 19-Jun-07
1780    ---------------------
1781    
1782     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1783        which is apparently normally available under Windows.
1784    
1785     2. Re-jig the pcregrep tests with different newline settings in an attempt
1786        to make them independent of the local environment's newline setting.
1787    
1788     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1789    
1790     4. Some of the "internals" tests were previously cut out when the link size
1791        was not 2, because the output contained actual offsets. The recent new
1792        "Z" feature of pcretest means that these can be cut out, making the tests
1793        usable with all link sizes.
1794    
1795     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1796        stack recursion. This gives a massive performance boost under BSD, but just
1797        a small improvement under Linux. However, it saves one field in the frame
1798        in all cases.
1799    
1800     6. Added more features from the forthcoming Perl 5.10:
1801    
1802        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1803            recursion call. It refers to the nth most recently opened parentheses.
1804    
1805        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1806            to be opened parentheses.
1807    
1808        (c) Conditions that refer to capturing parentheses can be specified
1809            relatively, for example, (?(-2)... or (?(+3)...
1810    
1811        (d) \K resets the start of the current match so that everything before
1812            is not part of it.
1813    
1814        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1815    
1816        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1817            reference syntax.
1818    
1819        (g) (?| introduces a group in which the numbering of parentheses in each
1820            alternative starts with the same number.
1821    
1822        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1823    
1824     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1825        PCRE_INFO_JCHANGED.
1826    
1827     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1828        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1829        for detecting groups that can match an empty string.
1830    
1831     9. A pattern with a very large number of alternatives (more than several
1832        hundred) was running out of internal workspace during the pre-compile
1833        phase, where pcre_compile() figures out how much memory will be needed. A
1834        bit of new cunning has reduced the workspace needed for groups with
1835        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1836        workspace instead of running out of the 4096 that are available.
1837    
1838    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1839    
1840    11. Applied patch from Google to remove an optimization that didn't quite work.
1841        The report of the bug said:
1842    
1843          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1844          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1845          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1846    
1847    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1848        it matched the wrong number of bytes.
1849    
1850    
1851  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
1852  ---------------------  ---------------------
1853    

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