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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-Mar-2010  Version 8.22
5    ------------
6    
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
9    
10    2.  Fixed a bug in the code for calculating the fixed length of lookbehind
11        assertions.
12    
13    
14    Version 8.21 12-Dec-2011
15    ------------------------
16    
17    1.  Updating the JIT compiler.
18    
19    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
20        are added as well.
21    
22    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
23        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
24        calling _pcre_jit_exec. Some extra comments are added.
25    
26    4.  (*MARK) settings inside atomic groups that do not contain any capturing
27        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
28        was introduced by change 18 for 8.20.
29    
30    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
31        ECMA-262 standard.
32    
33    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
34        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
35        This bug was probably introduced by change 9 of 8.13.
36    
37    7.  While fixing 6 above, I noticed that a number of other items were being
38        incorrectly rejected as "not fixed length". This arose partly because newer
39        opcodes had not been added to the fixed-length checking code. I have (a)
40        corrected the bug and added tests for these items, and (b) arranged for an
41        error to occur if an unknown opcode is encountered while checking for fixed
42        length instead of just assuming "not fixed length". The items that were
43        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
44        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
45        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
46    
47    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
48        being incorrectly compiled and would have given unpredicatble results.
49    
50    9.  A possessively repeated subpattern with minimum repeat count greater than
51        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
52        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
53        the first (A) could occur when it should not.
54    
55    10. Add a cast and remove a redundant test from the code.
56    
57    11. JIT should use pcre_malloc/pcre_free for allocation.
58    
59    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
60        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
61        is anything other than /usr, -L is still shown).
62    
63    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
64    
65    14. Perl does not support \N without a following name in a [] class; PCRE now
66        also gives an error.
67    
68    15. If a forward reference was repeated with an upper limit of around 2000,
69        it caused the error "internal error: overran compiling workspace". The
70        maximum number of forward references (including repeats) was limited by the
71        internal workspace, and dependent on the LINK_SIZE. The code has been
72        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
73        the default depends on LINK_SIZE. There is a new upper limit (for safety)
74        of around 200,000 forward references. While doing this, I also speeded up
75        the filling in of repeated forward references.
76    
77    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
78        incorrectly expecting the subject to contain another "a" after the start.
79    
80    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
81        in the match, the SKIP should be ignored. This was not happening; instead
82        the SKIP was being treated as NOMATCH. For patterns such as
83        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
84        tested.
85    
86    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
87        now much more compatible with Perl, in particular in cases where the result
88        is a non-match for a non-anchored pattern. For example, if
89        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
90        "m", where previously it did not return a name. A side effect of this
91        change is that for partial matches, the last encountered mark name is
92        returned, as for non matches. A number of tests that were previously not
93        Perl-compatible have been moved into the Perl-compatible test files. The
94        refactoring has had the pleasing side effect of removing one argument from
95        the match() function, thus reducing its stack requirements.
96    
97    19. If the /S+ option was used in pcretest to study a pattern using JIT,
98        subsequent uses of /S (without +) incorrectly behaved like /S+.
99    
100    21. Retrieve executable code size support for the JIT compiler and fixing
101        some warnings.
102    
103    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
104        not work when the shorter character appeared right at the end of the
105        subject string.
106    
107    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
108        systems.
109    
110    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
111        output it when the /M option is used in pcretest.
112    
113    25. The CheckMan script was not being included in the distribution. Also, added
114        an explicit "perl" to run Perl scripts from the PrepareRelease script
115        because this is reportedly needed in Windows.
116    
117    26. If study data was being save in a file and studying had not found a set of
118        "starts with" bytes for the pattern, the data written to the file (though
119        never used) was taken from uninitialized memory and so caused valgrind to
120        complain.
121    
122    27. Updated RunTest.bat as provided by Sheri Pierce.
123    
124    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
125    
126    29. Computation of memory usage for the table of capturing group names was
127        giving an unnecessarily large value.
128    
129    
130    Version 8.20 21-Oct-2011
131    ------------------------
132    
133    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
134        a POSIX class. After further experiments with Perl, which convinced me that
135        Perl has bugs and confusions, a closing square bracket is no longer allowed
136        in a POSIX name. This bug also affected patterns with classes that started
137        with full stops.
138    
139    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
140        captured substring, but while checking the failing first alternative,
141        substring 1 is temporarily captured. If the output vector supplied to
142        pcre_exec() was not big enough for this capture, the yield of the function
143        was still zero ("insufficient space for captured substrings"). This cannot
144        be totally fixed without adding another stack variable, which seems a lot
145        of expense for a edge case. However, I have improved the situation in cases
146        such as /(a)(b)x|abc/ matched against "abc", where the return code
147        indicates that fewer than the maximum number of slots in the ovector have
148        been set.
149    
150    3.  Related to (2) above: when there are more back references in a pattern than
151        slots in the output vector, pcre_exec() uses temporary memory during
152        matching, and copies in the captures as far as possible afterwards. It was
153        using the entire output vector, but this conflicts with the specification
154        that only 2/3 is used for passing back captured substrings. Now it uses
155        only the first 2/3, for compatibility. This is, of course, another edge
156        case.
157    
158    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
159        main code base, and can be used by building with --enable-jit. When this is
160        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
161        runtime --no-jit option is given.
162    
163    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
164        ovector, the return from the function was zero, implying that there were
165        other matches that did not fit. The correct "exactly full" value is now
166        returned.
167    
168    6.  If a subpattern that was called recursively or as a subroutine contained
169        (*PRUNE) or any other control that caused it to give a non-standard return,
170        invalid errors such as "Error -26 (nested recursion at the same subject
171        position)" or even infinite loops could occur.
172    
173    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
174        computing the minimum length on reaching *ACCEPT, and so ended up with the
175        wrong value of 1 rather than 0. Further investigation indicates that
176        computing a minimum subject length in the presence of *ACCEPT is difficult
177        (think back references, subroutine calls), and so I have changed the code
178        so that no minimum is registered for a pattern that contains *ACCEPT.
179    
180    8.  If (*THEN) was present in the first (true) branch of a conditional group,
181        it was not handled as intended. [But see 16 below.]
182    
183    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
184        Sheri Pierce.
185    
186    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
187        the first byte in a match must be "a".
188    
189    11. Change 17 for 8.13 increased the recursion depth for patterns like
190        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
191        pattern contains any instances of (*THEN). If it does not, the old
192        optimizations are restored. It would be nice to do this on a per-group
193        basis, but at the moment that is not feasible.
194    
195    12. In some environments, the output of pcretest -C is CRLF terminated. This
196        broke RunTest's code that checks for the link size. A single white space
197        character after the value is now allowed for.
198    
199    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
200        For "fr", it uses the Windows-specific input and output files.
201    
202    14. If (*THEN) appeared in a group that was called recursively or as a
203        subroutine, it did not work as intended. [But see next item.]
204    
205    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
206        pattern fragments (but not containing any | characters). If A and B are
207        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
208        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
209        D. In other words, Perl considers parentheses that do not contain any |
210        characters to be part of a surrounding alternative, whereas PCRE was
211        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
212        differently. PCRE now behaves in the same way as Perl, except in the case
213        of subroutine/recursion calls such as (?1) which have in any case always
214        been different (but PCRE had them first :-).
215    
216    16. Related to 15 above: Perl does not treat the | in a conditional group as
217        creating alternatives. Such a group is treated in the same way as an
218        ordinary group without any | characters when processing (*THEN). PCRE has
219        been changed to match Perl's behaviour.
220    
221    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
222        RunGrepTest script failed.
223    
224    18. Change 22 for version 13 caused atomic groups to use more stack. This is
225        inevitable for groups that contain captures, but it can lead to a lot of
226        stack use in large patterns. The old behaviour has been restored for atomic
227        groups that do not contain any capturing parentheses.
228    
229    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
230        suppress the check for a minimum subject length at run time. (If it was
231        given to pcre_exec() or pcre_dfa_exec() it did work.)
232    
233    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
234        fail to work when decoding hex characters in data strings in EBCDIC
235        environments.
236    
237    21. It appears that in at least one Mac OS environment, the isxdigit() function
238        is implemented as a macro that evaluates to its argument more than once,
239        contravening the C 90 Standard (I haven't checked a later standard). There
240        was an instance in pcretest which caused it to go wrong when processing
241        \x{...} escapes in subject strings. The has been rewritten to avoid using
242        things like p++ in the argument of isxdigit().
243    
244    
245    Version 8.13 16-Aug-2011
246    ------------------------
247    
248    1.  The Unicode data tables have been updated to Unicode 6.0.0.
249    
250    2.  Two minor typos in pcre_internal.h have been fixed.
251    
252    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
253        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
254        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
255    
256    4.  There were a number of related bugs in the code for matching backrefences
257        caselessly in UTF-8 mode when codes for the characters concerned were
258        different numbers of bytes. For example, U+023A and U+2C65 are an upper
259        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
260        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
261        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
262        2-byte code at the end of the subject (it thought there wasn't enough data
263        left).
264    
265    5.  Comprehensive information about what went wrong is now returned by
266        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
267        as the output vector has at least 2 elements. The offset of the start of
268        the failing character and a reason code are placed in the vector.
269    
270    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
271        now returned is for the first byte of the failing character, instead of the
272        last byte inspected. This is an incompatible change, but I hope it is small
273        enough not to be a problem. It makes the returned offset consistent with
274        pcre_exec() and pcre_dfa_exec().
275    
276    7.  pcretest now gives a text phrase as well as the error number when
277        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
278        failure, the offset and reason code are output.
279    
280    8.  When \R was used with a maximizing quantifier it failed to skip backwards
281        over a \r\n pair if the subsequent match failed. Instead, it just skipped
282        back over a single character (\n). This seems wrong (because it treated the
283        two characters as a single entity when going forwards), conflicts with the
284        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
285        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
286        has been changed.
287    
288    9.  Some internal refactoring has changed the processing so that the handling
289        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
290        time (the PCRE_DOTALL option was changed this way some time ago: version
291        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
292        which was always a bit of a fudge. It also means that there is one less
293        argument for the match() function, which reduces its stack requirements
294        slightly. This change also fixes an incompatibility with Perl: the pattern
295        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
296    
297    10. More internal refactoring has drastically reduced the number of recursive
298        calls to match() for possessively repeated groups such as (abc)++ when
299        using pcre_exec().
300    
301    11. While implementing 10, a number of bugs in the handling of groups were
302        discovered and fixed:
303    
304        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
305        (a|)*(?1) gave a compile-time internal error.
306        ((a|)+)+  did not notice that the outer group could match an empty string.
307        (^a|^)+   was not marked as anchored.
308        (.*a|.*)+ was not marked as matching at start or after a newline.
309    
310    12. Yet more internal refactoring has removed another argument from the match()
311        function. Special calls to this function are now indicated by setting a
312        value in a variable in the "match data" data block.
313    
314    13. Be more explicit in pcre_study() instead of relying on "default" for
315        opcodes that mean there is no starting character; this means that when new
316        ones are added and accidentally left out of pcre_study(), testing should
317        pick them up.
318    
319    14. The -s option of pcretest has been documented for ages as being an old
320        synonym of -m (show memory usage). I have changed it to mean "force study
321        for every regex", that is, assume /S for every regex. This is similar to -i
322        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
323        using it. It makes it easier to run collections of tests with and without
324        study enabled, and thereby test pcre_study() more easily. All the standard
325        tests are now run with and without -s (but some patterns can be marked as
326        "never study" - see 20 below).
327    
328    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
329        restoration of the capturing data to the outer values was not happening
330        correctly.
331    
332    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
333        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
334        pattern had matched an empty string, and so incorrectly returned a no
335        match.
336    
337    17. There was optimizing code for the last branch of non-capturing parentheses,
338        and also for the obeyed branch of a conditional subexpression, which used
339        tail recursion to cut down on stack usage. Unfortunately, now that there is
340        the possibility of (*THEN) occurring in these branches, tail recursion is
341        no longer possible because the return has to be checked for (*THEN). These
342        two optimizations have therefore been removed. [But see 8.20/11 above.]
343    
344    18. If a pattern containing \R was studied, it was assumed that \R always
345        matched two bytes, thus causing the minimum subject length to be
346        incorrectly computed because \R can also match just one byte.
347    
348    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
349        was incorrectly computed.
350    
351    20. If /S is present twice on a test pattern in pcretest input, it now
352        *disables* studying, thereby overriding the use of -s on the command line
353        (see 14 above). This is necessary for one or two tests to keep the output
354        identical in both cases.
355    
356    21. When (*ACCEPT) was used in an assertion that matched an empty string and
357        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
358    
359    22. When an atomic group that contained a capturing parenthesis was
360        successfully matched, but the branch in which it appeared failed, the
361        capturing was not being forgotten if a higher numbered group was later
362        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
363        group 1 to "a", when in fact it should be unset. This applied to multi-
364        branched capturing and non-capturing groups, repeated or not, and also to
365        positive assertions (capturing in negative assertions does not happen
366        in PCRE) and also to nested atomic groups.
367    
368    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
369        subject after a captured substring, to make it easier to tell which of a
370        number of identical substrings has been captured.
371    
372    24. The way atomic groups are processed by pcre_exec() has been changed so that
373        if they are repeated, backtracking one repetition now resets captured
374        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
375        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
376        "aaa". Previously, it would have been "a". As part of this code
377        refactoring, the way recursive calls are handled has also been changed.
378    
379    25. If an assertion condition captured any substrings, they were not passed
380        back unless some other capturing happened later. For example, if
381        (?(?=(a))a) was matched against "a", no capturing was returned.
382    
383    26. When studying a pattern that contained subroutine calls or assertions,
384        the code for finding the minimum length of a possible match was handling
385        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
386        group 1 called group 2 while simultaneously a separate group 2 called group
387        1). A stack overflow occurred in this case. I have fixed this by limiting
388        the recursion depth to 10.
389    
390    27. Updated RunTest.bat in the distribution to the version supplied by Tom
391        Fortmann. This supports explicit test numbers on the command line, and has
392        argument validation and error reporting.
393    
394    28. An instance of \X with an unlimited repeat could fail if at any point the
395        first character it looked at was a mark character.
396    
397    29. Some minor code refactoring concerning Unicode properties and scripts
398        should reduce the stack requirement of match() slightly.
399    
400    30. Added the '=' option to pcretest to check the setting of unused capturing
401        slots at the end of the pattern, which are documented as being -1, but are
402        not included in the return count.
403    
404    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
405        compiled something random. Now it gives a compile-time error (as does
406        Perl).
407    
408    32. A *MARK encountered during the processing of a positive assertion is now
409        recorded and passed back (compatible with Perl).
410    
411    33. If --only-matching or --colour was set on a pcregrep call whose pattern
412        had alternative anchored branches, the search for a second match in a line
413        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
414        matched the line "0102" twice. The same bug affected patterns that started
415        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
416        twice.
417    
418    34. Previously, PCRE did not allow quantification of assertions. However, Perl
419        does, and because of capturing effects, quantifying parenthesized
420        assertions may at times be useful. Quantifiers are now allowed for
421        parenthesized assertions.
422    
423    35. A minor code tidy in pcre_compile() when checking options for \R usage.
424    
425    36. \g was being checked for fancy things in a character class, when it should
426        just be a literal "g".
427    
428    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
429        appearance of a nested POSIX class supersedes an apparent external class.
430        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
431        unescaped square brackets may also appear as part of class names. For
432        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
433        more like Perl. (But see 8.20/1 above.)
434    
435    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
436        was because it thought it was \N{name}, which is not supported).
437    
438    39. Add minix to OS list not supporting the -S option in pcretest.
439    
440    40. PCRE tries to detect cases of infinite recursion at compile time, but it
441        cannot analyze patterns in sufficient detail to catch mutual recursions
442        such as ((?1))((?2)). There is now a runtime test that gives an error if a
443        subgroup is called recursively as a subpattern for a second time at the
444        same position in the subject string. In previous releases this might have
445        been caught by the recursion limit, or it might have run out of stack.
446    
447    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
448        happen only once. PCRE was, however incorrectly giving a compile time error
449        "recursive call could loop indefinitely" because it cannot analyze the
450        pattern in sufficient detail. The compile time test no longer happens when
451        PCRE is compiling a conditional subpattern, but actual runaway loops are
452        now caught at runtime (see 40 above).
453    
454    42. It seems that Perl allows any characters other than a closing parenthesis
455        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
456        has been changed to be the same.
457    
458    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
459        as not to get warnings when autogen.sh is called. Also changed
460        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
461    
462    44. To help people who use pcregrep to scan files containing exceedingly long
463        lines, the following changes have been made:
464    
465        (a) The default value of the buffer size parameter has been increased from
466            8K to 20K. (The actual buffer used is three times this size.)
467    
468        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
469            PCRE is built.
470    
471        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
472            to be set at run time.
473    
474        (d) Numerical values in pcregrep options can be followed by K or M, for
475            example --buffer-size=50K.
476    
477        (e) If a line being scanned overflows pcregrep's buffer, an error is now
478            given and the return code is set to 2.
479    
480    45. Add a pointer to the latest mark to the callout data block.
481    
482    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
483        partial match of an empty string instead of no match. This was specific to
484        the use of ".".
485    
486    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
487        complete match instead of a partial match. This bug was dependent on both
488        the PCRE_UTF8 and PCRE_DOTALL options being set.
489    
490    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
491        starting byte set, because \b was not being ignored.
492    
493    
494    Version 8.12 15-Jan-2011
495    ------------------------
496    
497    1.  Fixed some typos in the markup of the man pages, and wrote a script that
498        checks for such things as part of the documentation building process.
499    
500    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
501        --match-limit and --recursion-limit options (added for 8.11). In
502        particular, this made one of the standard tests fail. (The integer value
503        went into the wrong half of a long int.)
504    
505    3.  If the --colour option was given to pcregrep with -v (invert match), it
506        did strange things, either producing crazy output, or crashing. It should,
507        of course, ignore a request for colour when reporting lines that do not
508        match.
509    
510    4.  Another pcregrep bug caused similar problems if --colour was specified with
511        -M (multiline) and the pattern match finished with a line ending.
512    
513    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
514        matched in multiline mode, the following line was shown as part of the
515        match. This seems wrong, so I have changed it.
516    
517    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
518        the check for further matches in the same line (so they could be coloured)
519        to overrun the end of the current line. If another match was found, it was
520        incorrectly shown (and then shown again when found in the next line).
521    
522    7.  If pcregrep was compiled under Windows, there was a reference to the
523        function pcregrep_exit() before it was defined. I am assuming this was
524        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
525        reported by a user. I've moved the definition above the reference.
526    
527    
528    Version 8.11 10-Dec-2010
529    ------------------------
530    
531    1.  (*THEN) was not working properly if there were untried alternatives prior
532        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
533        backtracked to try for "b" instead of moving to the next alternative branch
534        at the same level (in this case, to look for "c"). The Perl documentation
535        is clear that when (*THEN) is backtracked onto, it goes to the "next
536        alternative in the innermost enclosing group".
537    
538    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
539        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
540        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
541        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
542        (*THEN).
543    
544    3.  If \s appeared in a character class, it removed the VT character from
545        the class, even if it had been included by some previous item, for example
546        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
547        of \s, but is part of the POSIX "space" class.)
548    
549    4.  A partial match never returns an empty string (because you can always
550        match an empty string at the end of the subject); however the checking for
551        an empty string was starting at the "start of match" point. This has been
552        changed to the "earliest inspected character" point, because the returned
553        data for a partial match starts at this character. This means that, for
554        example, /(?<=abc)def/ gives a partial match for the subject "abc"
555        (previously it gave "no match").
556    
557    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
558        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
559        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
560        has an implication that the given string is incomplete (because a partial
561        match is preferred over a full match). For this reason, these items now
562        give a partial match in this situation. [Aside: previously, the one case
563        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
564        match rather than a full match, which was wrong by the old rules, but is
565        now correct.]
566    
567    6.  There was a bug in the handling of #-introduced comments, recognized when
568        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
569        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
570        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
571        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
572        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
573        places in pcre_compile().
574    
575    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
576        comments when looking ahead for named forward references to subpatterns,
577        the only newline sequence it recognized was NL. It now handles newlines
578        according to the set newline convention.
579    
580    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
581        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
582        cater for a lack of strerror(). These oversights have been fixed.
583    
584    9.  Added --match-limit and --recursion-limit to pcregrep.
585    
586    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
587    
588    11. When the -o option was used, pcregrep was setting a return code of 1, even
589        when matches were found, and --line-buffered was not being honoured.
590    
591    12. Added an optional parentheses number to the -o and --only-matching options
592        of pcregrep.
593    
594    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
595        can match an empty string. The code to do it in pcretest and pcredemo
596        needed fixing:
597    
598        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
599            only one byte after an empty string match just before CRLF (this case
600            just got forgotten; "any" and "anycrlf" were OK).
601    
602        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
603            mode when an empty string match preceded an ASCII character followed by
604            a non-ASCII character. (The code for advancing by one character rather
605            than one byte was nonsense.)
606    
607        (c) The pcredemo.c sample program did not have any code at all to handle
608            the cases when CRLF is a valid newline sequence.
609    
610    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
611        as a starting offset was within the subject string. There is now a new
612        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
613        negative or greater than the length of the string. In order to test this,
614        pcretest is extended to allow the setting of negative starting offsets.
615    
616    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
617        starting offset points to the beginning of a UTF-8 character was
618        unnecessarily clumsy. I tidied it up.
619    
620    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
621        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
622    
623    17. Nobody had reported that the --include_dir option, which was added in
624        release 7.7 should have been called --include-dir (hyphen, not underscore)
625        for compatibility with GNU grep. I have changed it to --include-dir, but
626        left --include_dir as an undocumented synonym, and the same for
627        --exclude-dir, though that is not available in GNU grep, at least as of
628        release 2.5.4.
629    
630    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
631        characters from a string of bytes) have been redefined so as not to use
632        loops, in order to improve performance in some environments. At the same
633        time, I abstracted some of the common code into auxiliary macros to save
634        repetition (this should not affect the compiled code).
635    
636    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
637        compile-time error is now given if \c is not followed by an ASCII
638        character, that is, a byte less than 128. (In EBCDIC mode, the code is
639        different, and any byte value is allowed.)
640    
641    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
642        START_OPTIMIZE option, which is now allowed at compile time - but just
643        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
644        to pcregrep and other applications that have no direct access to PCRE
645        options. The new /Y option in pcretest sets this option when calling
646        pcre_compile().
647    
648    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
649        back references. Groups containing recursive back references were forced to
650        be atomic by that change, but in the case of named groups, the amount of
651        memory required was incorrectly computed, leading to "Failed: internal
652        error: code overflow". This has been fixed.
653    
654    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
655        pcretest.c, to avoid build problems in some Borland environments.
656    
657    
658    Version 8.10 25-Jun-2010
659    ------------------------
660    
661    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
662        THEN.
663    
664    2.  (*ACCEPT) was not working when inside an atomic group.
665    
666    3.  Inside a character class, \B is treated as a literal by default, but
667        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
668        causes the error). The code is unchanged, but I tidied the documentation.
669    
670    4.  Inside a character class, PCRE always treated \R and \X as literals,
671        whereas Perl faults them if its -w option is set. I have changed PCRE so
672        that it faults them when PCRE_EXTRA is set.
673    
674    5.  Added support for \N, which always matches any character other than
675        newline. (It is the same as "." when PCRE_DOTALL is not set.)
676    
677    6.  When compiling pcregrep with newer versions of gcc which may have
678        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
679        declared with attribute warn_unused_result" were given. Just casting the
680        result to (void) does not stop the warnings; a more elaborate fudge is
681        needed. I've used a macro to implement this.
682    
683    7.  Minor change to pcretest.c to avoid a compiler warning.
684    
685    8.  Added four artifical Unicode properties to help with an option to make
686        \s etc use properties (see next item). The new properties are: Xan
687        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
688    
689    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
690        use Unicode properties. (*UCP) at the start of a pattern can be used to set
691        this option. Modified pcretest to add /W to test this facility. Added
692        REG_UCP to make it available via the POSIX interface.
693    
694    10. Added --line-buffered to pcregrep.
695    
696    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
697        studied, and the match started with a letter with a code point greater than
698        127 whose first byte was different to the first byte of the other case of
699        the letter, the other case of this starting letter was not recognized
700        (#976).
701    
702    12. If a pattern that was studied started with a repeated Unicode property
703        test, for example, \p{Nd}+, there was the theoretical possibility of
704        setting up an incorrect bitmap of starting bytes, but fortunately it could
705        not have actually happened in practice until change 8 above was made (it
706        added property types that matched character-matching opcodes).
707    
708    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
709        possible starting bytes for non-anchored patterns.
710    
711    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
712        \R, and also a number of cases that involve Unicode properties, both
713        explicit and implicit when PCRE_UCP is set.
714    
715    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
716        input, it could crash or give wrong results if characters with values
717        greater than 0xc0 were present in the subject string. (Detail: it assumed
718        UTF-8 input when processing these items.)
719    
720    16. Added a lot of (int) casts to avoid compiler warnings in systems where
721        size_t is 64-bit (#991).
722    
723    17. Added a check for running out of memory when PCRE is compiled with
724        --disable-stack-for-recursion (#990).
725    
726    18. If the last data line in a file for pcretest does not have a newline on
727        the end, a newline was missing in the output.
728    
729    19. The default pcre_chartables.c file recognizes only ASCII characters (values
730        less than 128) in its various bitmaps. However, there is a facility for
731        generating tables according to the current locale when PCRE is compiled. It
732        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
733        characters, are recognized by isspace() and therefore were getting set in
734        these tables, and indeed these tables seem to approximate to ISO 8859. This
735        caused a problem in UTF-8 mode when pcre_study() was used to create a list
736        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
737        which of course cannot start UTF-8 characters. I have changed the code so
738        that only real ASCII characters (less than 128) and the correct starting
739        bytes for UTF-8 encodings are set for characters greater than 127 when in
740        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
741        altogether.)
742    
743    20. Added the /T option to pcretest so as to be able to run tests with non-
744        standard character tables, thus making it possible to include the tests
745        used for 19 above in the standard set of tests.
746    
747    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
748        reference to a subpattern the other side of a comment that contains an
749        opening parenthesis caused either an internal compiling error, or a
750        reference to the wrong subpattern.
751    
752    
753    Version 8.02 19-Mar-2010
754  ------------------------  ------------------------
755    
756  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
757    
758  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
759      configured.      configured.
760    
761  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
762      original author of that file, following a query about its status.      original author of that file, following a query about its status.
763    
764  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
765      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
766    
767  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
768      quantifier applied to a forward-referencing subroutine call, could compile      quantifier applied to a forward-referencing subroutine call, could compile
769      incorrect code or give the error "internal error: previously-checked      incorrect code or give the error "internal error: previously-checked
770      referenced subpattern not found".      referenced subpattern not found".
771    
772  6.  Both MS Visual Studio and Symbian OS have problems with initializing  6.  Both MS Visual Studio and Symbian OS have problems with initializing
773      variables to point to external functions. For these systems, therefore,      variables to point to external functions. For these systems, therefore,
774      pcre_malloc etc. are now initialized to local functions that call the      pcre_malloc etc. are now initialized to local functions that call the
775      relevant global functions.      relevant global functions.
776    
777  7.  There were two entries missing in the vectors called coptable and poptable  7.  There were two entries missing in the vectors called coptable and poptable
778      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
779      I've fixed the data, and added a kludgy way of testing at compile time that      I've fixed the data, and added a kludgy way of testing at compile time that
780      the lengths are correct (equal to the number of opcodes).      the lengths are correct (equal to the number of opcodes).
781    
782  8.  Following on from 7, I added a similar kludge to check the length of the  8.  Following on from 7, I added a similar kludge to check the length of the
783      eint vector in pcreposix.c.      eint vector in pcreposix.c.
784    
785  9.  Error texts for pcre_compile() are held as one long string to avoid too  9.  Error texts for pcre_compile() are held as one long string to avoid too
786      much relocation at load time. To find a text, the string is searched,      much relocation at load time. To find a text, the string is searched,
787      counting zeros. There was no check for running off the end of the string,      counting zeros. There was no check for running off the end of the string,
788      which could happen if a new error number was added without updating the      which could happen if a new error number was added without updating the
789      string.      string.
790    
791    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
792    
793    11. \K was not working if it appeared in an atomic group or in a group that
794        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
795        \K is "not well defined" if used in an assertion. PCRE now accepts it if
796        the assertion is positive, but not if it is negative.
797    
798    12. Change 11 fortuitously reduced the size of the stack frame used in the
799        "match()" function of pcre_exec.c by one pointer. Forthcoming
800        implementation of support for (*MARK) will need an extra pointer on the
801        stack; I have reserved it now, so that the stack frame size does not
802        decrease.
803    
804    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
805        item in branch that calls a recursion is a subroutine call - as in the
806        second branch in the above example - was incorrectly given the compile-
807        time error "recursive call could loop indefinitely" because pcre_compile()
808        was not correctly checking the subroutine for matching a non-empty string.
809    
810    14. The checks for overrunning compiling workspace could trigger after an
811        overrun had occurred. This is a "should never occur" error, but it can be
812        triggered by pathological patterns such as hundreds of nested parentheses.
813        The checks now trigger 100 bytes before the end of the workspace.
814    
815    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
816    
817    
818  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010

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