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revision 663 by ph10, Mon Aug 22 14:53:12 2011 UTC revision 967 by zherczeg, Mon May 14 07:36:39 2012 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.20  Version 8.31
5  ------------  -----------------------------
6    
7  1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had  1.  Fixing a wrong JIT test case and some compiler warnings.
8     a POSIX class. After further experiments with Perl, which convinced me that  
9     Perl has bugs and confusions, a closing square bracket is no longer allowed  2.  Removed a bashism from the RunTest script.
10     in a POSIX name.  
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12  2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured      to unsigned type, result still unsigned" that was given by an MS compiler
13     substring, but while checking the failing first alternative, substring 1 is      on encountering the code "-sizeof(xxx)".
14     temporarily captured. If the output vector supplied to pcre_exec() was not  
15     big enough for this capture, the yield of the function was still zero  4.  Partial matching support is added to the JIT compiler.
16     ("insufficient space for captured substrings"). This cannot be totally fixed  
17     without adding another stack variable, which seems a lot of expense for a  5.  Fixed several bugs concerned with partial matching of items that consist
18     edge case. However, I have improved the situation in cases such as      of more than one character:
19     /(a)(b)x|abc/ matched against "abc", where the return code indicates that  
20     fewer than the maximum number of slots in the ovector have been set.      (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22  3. Related to (2) above: when there are more back references in a pattern than          references.
23     slots in the output vector, pcre_exec() uses temporary memory during  
24     matching, and copies in the captures as far as possible afterwards. It was      (b) \R did not give a hard partial match if \r was found at the end of the
25     using the entire output vector, but this conflicts with the specification          subject.
26     that only 2/3 is used for passing back captured substrings. Now it uses only  
27     the first 2/3, for compatibility. This is, of course, another edge case.      (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
39    
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
42    
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
44    
45    9.  (*MARK) control verb is now supported by the JIT compiler.
46    
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
49    
50    11. Add PCRE_INFO_MAXLOOKBEHIND.
51    
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
57    
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
60    
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
62    
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
65    
66    16. (*COMMIT) control verb is now supported by the JIT compiler.
67    
68    17. The Unicode data tables have been updated to Unicode 6.1.0.
69    
70    18. Added --file-list option to pcregrep.
71    
72    19. Added binary file support to pcregrep, including the -a, --binary-files,
73        -I, and --text options.
74    
75    20. The madvise function is renamed for posix_madvise for QNX compatibility
76        reasons. Fixed by Giuseppe D'Angelo.
77    
78    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
79    
80    22. Changed the option for creating symbolic links for 16-bit man pages from
81        -s to -sf so that re-installing does not cause issues.
82    
83    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
84    
85    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
86        matches in certain environments (the workspace was not being correctly
87        retained). Also added to pcre_dfa_exec() a simple plausibility check on
88        some of the workspace data at the beginning of a restart.
89    
90    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
91        was not doing so when it should - probably a typo introduced by SVN 528
92        (change 8.10/14).
93    
94    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
95        \w+ when the character tables indicated that \x{c4} was a word character.
96        There were several related cases, all because the tests for doing a table
97        lookup were testing for characters less than 127 instead of 255.
98    
99    27. If a pattern contains capturing parentheses that are not used in a match,
100        their slots in the ovector are set to -1. For those that are higher than
101        any matched groups, this happens at the end of processing. In the case when
102        there were back references that the ovector was too small to contain
103        (causing temporary malloc'd memory to be used during matching), and the
104        highest capturing number was not used, memory off the end of the ovector
105        was incorrectly being set to -1. (It was using the size of the temporary
106        memory instead of the true size.)
107    
108    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
109        ovector size, it uses memory at the end of the block that it has got.
110    
111    29. Check for an overlong MARK name and give an error at compile time. The
112        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
113    
114    30. JIT compiler update.
115    
116    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
117        Rill for the patch.
118    
119    
120    Version 8.30 04-February-2012
121    -----------------------------
122    
123    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
124        name is defined in ctype.h.
125    
126    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
127        only in quite long subpatterns.
128    
129    3.  Removed the function pcre_info(), which has been obsolete and deprecated
130        since it was replaced by pcre_fullinfo() in February 2000.
131    
132    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
133        match a (*MARK), and the match failed at the start of the subject, a
134        reference to memory before the start of the subject could occur. This bug
135        was introduced by fix 17 of release 8.21.
136    
137    5.  A reference to an unset group with zero minimum repetition was giving
138        totally wrong answers (in non-JavaScript-compatibility mode). For example,
139        /(another)?(\1?)test/ matched against "hello world test". This bug was
140        introduced in release 8.13.
141    
142    6.  Add support for 16-bit character strings (a large amount of work involving
143        many changes and refactorings).
144    
145    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
146        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
147        from a file.
148    
149    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
150        rounding is not applied in this particular case).
151    
152    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
153        if they appear, or are escaped, in patterns.
154    
155    10. Get rid of a number of -Wunused-but-set-variable warnings.
156    
157    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
158        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
159        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
160        also returns the mark "x". This bug applied to capturing parentheses,
161        non-capturing parentheses, and atomic parentheses. It also applied to some
162        assertions.
163    
164    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
165        information out of configure.ac instead of relying on pcre.h.generic, which
166        is not stored in the repository.
167    
168    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
169        -lreadline.
170    
171    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
172    
173    15. Applied Graycode's patch to put the top-level frame on the stack rather
174        than the heap when not using the stack for recursion. This gives a
175        performance improvement in many cases when recursion is not deep.
176    
177    16. Experimental code added to "pcretest -C" to output the stack frame size.
178    
179    
180    Version 8.21 12-Dec-2011
181    ------------------------
182    
183    1.  Updating the JIT compiler.
184    
185    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
186        are added as well.
187    
188    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
189        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
190        calling _pcre_jit_exec. Some extra comments are added.
191    
192    4.  (*MARK) settings inside atomic groups that do not contain any capturing
193        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
194        was introduced by change 18 for 8.20.
195    
196    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
197        ECMA-262 standard.
198    
199    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
200        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
201        This bug was probably introduced by change 9 of 8.13.
202    
203    7.  While fixing 6 above, I noticed that a number of other items were being
204        incorrectly rejected as "not fixed length". This arose partly because newer
205        opcodes had not been added to the fixed-length checking code. I have (a)
206        corrected the bug and added tests for these items, and (b) arranged for an
207        error to occur if an unknown opcode is encountered while checking for fixed
208        length instead of just assuming "not fixed length". The items that were
209        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
210        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
211        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
212    
213    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
214        being incorrectly compiled and would have given unpredicatble results.
215    
216    9.  A possessively repeated subpattern with minimum repeat count greater than
217        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
218        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
219        the first (A) could occur when it should not.
220    
221    10. Add a cast and remove a redundant test from the code.
222    
223    11. JIT should use pcre_malloc/pcre_free for allocation.
224    
225    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
226        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
227        is anything other than /usr, -L is still shown).
228    
229    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
230    
231    14. Perl does not support \N without a following name in a [] class; PCRE now
232        also gives an error.
233    
234    15. If a forward reference was repeated with an upper limit of around 2000,
235        it caused the error "internal error: overran compiling workspace". The
236        maximum number of forward references (including repeats) was limited by the
237        internal workspace, and dependent on the LINK_SIZE. The code has been
238        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
239        the default depends on LINK_SIZE. There is a new upper limit (for safety)
240        of around 200,000 forward references. While doing this, I also speeded up
241        the filling in of repeated forward references.
242    
243    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
244        incorrectly expecting the subject to contain another "a" after the start.
245    
246    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
247        in the match, the SKIP should be ignored. This was not happening; instead
248        the SKIP was being treated as NOMATCH. For patterns such as
249        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
250        tested.
251    
252    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
253        now much more compatible with Perl, in particular in cases where the result
254        is a non-match for a non-anchored pattern. For example, if
255        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
256        "m", where previously it did not return a name. A side effect of this
257        change is that for partial matches, the last encountered mark name is
258        returned, as for non matches. A number of tests that were previously not
259        Perl-compatible have been moved into the Perl-compatible test files. The
260        refactoring has had the pleasing side effect of removing one argument from
261        the match() function, thus reducing its stack requirements.
262    
263    19. If the /S+ option was used in pcretest to study a pattern using JIT,
264        subsequent uses of /S (without +) incorrectly behaved like /S+.
265    
266    21. Retrieve executable code size support for the JIT compiler and fixing
267        some warnings.
268    
269    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
270        not work when the shorter character appeared right at the end of the
271        subject string.
272    
273    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
274        systems.
275    
276    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
277        output it when the /M option is used in pcretest.
278    
279    25. The CheckMan script was not being included in the distribution. Also, added
280        an explicit "perl" to run Perl scripts from the PrepareRelease script
281        because this is reportedly needed in Windows.
282    
283    26. If study data was being save in a file and studying had not found a set of
284        "starts with" bytes for the pattern, the data written to the file (though
285        never used) was taken from uninitialized memory and so caused valgrind to
286        complain.
287    
288    27. Updated RunTest.bat as provided by Sheri Pierce.
289    
290    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
291    
292    29. Computation of memory usage for the table of capturing group names was
293        giving an unnecessarily large value.
294    
295    
296    Version 8.20 21-Oct-2011
297    ------------------------
298    
299    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
300        a POSIX class. After further experiments with Perl, which convinced me that
301        Perl has bugs and confusions, a closing square bracket is no longer allowed
302        in a POSIX name. This bug also affected patterns with classes that started
303        with full stops.
304    
305    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
306        captured substring, but while checking the failing first alternative,
307        substring 1 is temporarily captured. If the output vector supplied to
308        pcre_exec() was not big enough for this capture, the yield of the function
309        was still zero ("insufficient space for captured substrings"). This cannot
310        be totally fixed without adding another stack variable, which seems a lot
311        of expense for a edge case. However, I have improved the situation in cases
312        such as /(a)(b)x|abc/ matched against "abc", where the return code
313        indicates that fewer than the maximum number of slots in the ovector have
314        been set.
315    
316    3.  Related to (2) above: when there are more back references in a pattern than
317        slots in the output vector, pcre_exec() uses temporary memory during
318        matching, and copies in the captures as far as possible afterwards. It was
319        using the entire output vector, but this conflicts with the specification
320        that only 2/3 is used for passing back captured substrings. Now it uses
321        only the first 2/3, for compatibility. This is, of course, another edge
322        case.
323    
324    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
325        main code base, and can be used by building with --enable-jit. When this is
326        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
327        runtime --no-jit option is given.
328    
329    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
330        ovector, the return from the function was zero, implying that there were
331        other matches that did not fit. The correct "exactly full" value is now
332        returned.
333    
334    6.  If a subpattern that was called recursively or as a subroutine contained
335        (*PRUNE) or any other control that caused it to give a non-standard return,
336        invalid errors such as "Error -26 (nested recursion at the same subject
337        position)" or even infinite loops could occur.
338    
339    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
340        computing the minimum length on reaching *ACCEPT, and so ended up with the
341        wrong value of 1 rather than 0. Further investigation indicates that
342        computing a minimum subject length in the presence of *ACCEPT is difficult
343        (think back references, subroutine calls), and so I have changed the code
344        so that no minimum is registered for a pattern that contains *ACCEPT.
345    
346    8.  If (*THEN) was present in the first (true) branch of a conditional group,
347        it was not handled as intended. [But see 16 below.]
348    
349    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
350        Sheri Pierce.
351    
352    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
353        the first byte in a match must be "a".
354    
355    11. Change 17 for 8.13 increased the recursion depth for patterns like
356        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
357        pattern contains any instances of (*THEN). If it does not, the old
358        optimizations are restored. It would be nice to do this on a per-group
359        basis, but at the moment that is not feasible.
360    
361    12. In some environments, the output of pcretest -C is CRLF terminated. This
362        broke RunTest's code that checks for the link size. A single white space
363        character after the value is now allowed for.
364    
365    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
366        For "fr", it uses the Windows-specific input and output files.
367    
368    14. If (*THEN) appeared in a group that was called recursively or as a
369        subroutine, it did not work as intended. [But see next item.]
370    
371    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
372        pattern fragments (but not containing any | characters). If A and B are
373        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
374        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
375        D. In other words, Perl considers parentheses that do not contain any |
376        characters to be part of a surrounding alternative, whereas PCRE was
377        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
378        differently. PCRE now behaves in the same way as Perl, except in the case
379        of subroutine/recursion calls such as (?1) which have in any case always
380        been different (but PCRE had them first :-).
381    
382    16. Related to 15 above: Perl does not treat the | in a conditional group as
383        creating alternatives. Such a group is treated in the same way as an
384        ordinary group without any | characters when processing (*THEN). PCRE has
385        been changed to match Perl's behaviour.
386    
387    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
388        RunGrepTest script failed.
389    
390    18. Change 22 for version 13 caused atomic groups to use more stack. This is
391        inevitable for groups that contain captures, but it can lead to a lot of
392        stack use in large patterns. The old behaviour has been restored for atomic
393        groups that do not contain any capturing parentheses.
394    
395    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
396        suppress the check for a minimum subject length at run time. (If it was
397        given to pcre_exec() or pcre_dfa_exec() it did work.)
398    
399    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
400        fail to work when decoding hex characters in data strings in EBCDIC
401        environments.
402    
403    21. It appears that in at least one Mac OS environment, the isxdigit() function
404        is implemented as a macro that evaluates to its argument more than once,
405        contravening the C 90 Standard (I haven't checked a later standard). There
406        was an instance in pcretest which caused it to go wrong when processing
407        \x{...} escapes in subject strings. The has been rewritten to avoid using
408        things like p++ in the argument of isxdigit().
409    
410    
411  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
# Line 124  Version 8.13 16-Aug-2011 Line 505  Version 8.13 16-Aug-2011
505      tail recursion to cut down on stack usage. Unfortunately, now that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
506      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
507      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
508      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
509    
510  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
511      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be

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