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revision 672 by ph10, Tue Aug 23 16:45:55 2011 UTC revision 942 by ph10, Tue Feb 28 14:50:31 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  4. Zoltan Herczeg's just-in-time compiler support has been integrated into the  
30     main code base, and can be used by building with --enable-jit.      (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    6.  The Unicode data tables have been updated to Unicode 6.1.0.
69    
70    
71    Version 8.30 04-February-2012
72    -----------------------------
73    
74    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
75        name is defined in ctype.h.
76    
77    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
78        only in quite long subpatterns.
79    
80    3.  Removed the function pcre_info(), which has been obsolete and deprecated
81        since it was replaced by pcre_fullinfo() in February 2000.
82    
83    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
84        match a (*MARK), and the match failed at the start of the subject, a
85        reference to memory before the start of the subject could occur. This bug
86        was introduced by fix 17 of release 8.21.
87    
88    5.  A reference to an unset group with zero minimum repetition was giving
89        totally wrong answers (in non-JavaScript-compatibility mode). For example,
90        /(another)?(\1?)test/ matched against "hello world test". This bug was
91        introduced in release 8.13.
92    
93    6.  Add support for 16-bit character strings (a large amount of work involving
94        many changes and refactorings).
95    
96    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
97        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
98        from a file.
99    
100    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
101        rounding is not applied in this particular case).
102    
103    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
104        if they appear, or are escaped, in patterns.
105    
106    10. Get rid of a number of -Wunused-but-set-variable warnings.
107    
108    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
109        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
110        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
111        also returns the mark "x". This bug applied to capturing parentheses,
112        non-capturing parentheses, and atomic parentheses. It also applied to some
113        assertions.
114    
115    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
116        information out of configure.ac instead of relying on pcre.h.generic, which
117        is not stored in the repository.
118    
119    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
120        -lreadline.
121    
122    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
123    
124    15. Applied Graycode's patch to put the top-level frame on the stack rather
125        than the heap when not using the stack for recursion. This gives a
126        performance improvement in many cases when recursion is not deep.
127    
128    16. Experimental code added to "pcretest -C" to output the stack frame size.
129    
130    
131    Version 8.21 12-Dec-2011
132    ------------------------
133    
134    1.  Updating the JIT compiler.
135    
136    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
137        are added as well.
138    
139    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
140        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
141        calling _pcre_jit_exec. Some extra comments are added.
142    
143    4.  (*MARK) settings inside atomic groups that do not contain any capturing
144        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
145        was introduced by change 18 for 8.20.
146    
147    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
148        ECMA-262 standard.
149    
150    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
151        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
152        This bug was probably introduced by change 9 of 8.13.
153    
154    7.  While fixing 6 above, I noticed that a number of other items were being
155        incorrectly rejected as "not fixed length". This arose partly because newer
156        opcodes had not been added to the fixed-length checking code. I have (a)
157        corrected the bug and added tests for these items, and (b) arranged for an
158        error to occur if an unknown opcode is encountered while checking for fixed
159        length instead of just assuming "not fixed length". The items that were
160        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
161        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
162        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
163    
164    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
165        being incorrectly compiled and would have given unpredicatble results.
166    
167    9.  A possessively repeated subpattern with minimum repeat count greater than
168        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
169        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
170        the first (A) could occur when it should not.
171    
172    10. Add a cast and remove a redundant test from the code.
173    
174    11. JIT should use pcre_malloc/pcre_free for allocation.
175    
176    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
177        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
178        is anything other than /usr, -L is still shown).
179    
180    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
181    
182    14. Perl does not support \N without a following name in a [] class; PCRE now
183        also gives an error.
184    
185    15. If a forward reference was repeated with an upper limit of around 2000,
186        it caused the error "internal error: overran compiling workspace". The
187        maximum number of forward references (including repeats) was limited by the
188        internal workspace, and dependent on the LINK_SIZE. The code has been
189        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
190        the default depends on LINK_SIZE. There is a new upper limit (for safety)
191        of around 200,000 forward references. While doing this, I also speeded up
192        the filling in of repeated forward references.
193    
194    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
195        incorrectly expecting the subject to contain another "a" after the start.
196    
197    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
198        in the match, the SKIP should be ignored. This was not happening; instead
199        the SKIP was being treated as NOMATCH. For patterns such as
200        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
201        tested.
202    
203    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
204        now much more compatible with Perl, in particular in cases where the result
205        is a non-match for a non-anchored pattern. For example, if
206        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
207        "m", where previously it did not return a name. A side effect of this
208        change is that for partial matches, the last encountered mark name is
209        returned, as for non matches. A number of tests that were previously not
210        Perl-compatible have been moved into the Perl-compatible test files. The
211        refactoring has had the pleasing side effect of removing one argument from
212        the match() function, thus reducing its stack requirements.
213    
214    19. If the /S+ option was used in pcretest to study a pattern using JIT,
215        subsequent uses of /S (without +) incorrectly behaved like /S+.
216    
217    21. Retrieve executable code size support for the JIT compiler and fixing
218        some warnings.
219    
220    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
221        not work when the shorter character appeared right at the end of the
222        subject string.
223    
224    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
225        systems.
226    
227    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
228        output it when the /M option is used in pcretest.
229    
230    25. The CheckMan script was not being included in the distribution. Also, added
231        an explicit "perl" to run Perl scripts from the PrepareRelease script
232        because this is reportedly needed in Windows.
233    
234    26. If study data was being save in a file and studying had not found a set of
235        "starts with" bytes for the pattern, the data written to the file (though
236        never used) was taken from uninitialized memory and so caused valgrind to
237        complain.
238    
239    27. Updated RunTest.bat as provided by Sheri Pierce.
240    
241    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
242    
243    29. Computation of memory usage for the table of capturing group names was
244        giving an unnecessarily large value.
245    
246    
247    Version 8.20 21-Oct-2011
248    ------------------------
249    
250    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
251        a POSIX class. After further experiments with Perl, which convinced me that
252        Perl has bugs and confusions, a closing square bracket is no longer allowed
253        in a POSIX name. This bug also affected patterns with classes that started
254        with full stops.
255    
256    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
257        captured substring, but while checking the failing first alternative,
258        substring 1 is temporarily captured. If the output vector supplied to
259        pcre_exec() was not big enough for this capture, the yield of the function
260        was still zero ("insufficient space for captured substrings"). This cannot
261        be totally fixed without adding another stack variable, which seems a lot
262        of expense for a edge case. However, I have improved the situation in cases
263        such as /(a)(b)x|abc/ matched against "abc", where the return code
264        indicates that fewer than the maximum number of slots in the ovector have
265        been set.
266    
267    3.  Related to (2) above: when there are more back references in a pattern than
268        slots in the output vector, pcre_exec() uses temporary memory during
269        matching, and copies in the captures as far as possible afterwards. It was
270        using the entire output vector, but this conflicts with the specification
271        that only 2/3 is used for passing back captured substrings. Now it uses
272        only the first 2/3, for compatibility. This is, of course, another edge
273        case.
274    
275    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
276        main code base, and can be used by building with --enable-jit. When this is
277        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
278        runtime --no-jit option is given.
279    
280    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
281        ovector, the return from the function was zero, implying that there were
282        other matches that did not fit. The correct "exactly full" value is now
283        returned.
284    
285    6.  If a subpattern that was called recursively or as a subroutine contained
286        (*PRUNE) or any other control that caused it to give a non-standard return,
287        invalid errors such as "Error -26 (nested recursion at the same subject
288        position)" or even infinite loops could occur.
289    
290    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
291        computing the minimum length on reaching *ACCEPT, and so ended up with the
292        wrong value of 1 rather than 0. Further investigation indicates that
293        computing a minimum subject length in the presence of *ACCEPT is difficult
294        (think back references, subroutine calls), and so I have changed the code
295        so that no minimum is registered for a pattern that contains *ACCEPT.
296    
297    8.  If (*THEN) was present in the first (true) branch of a conditional group,
298        it was not handled as intended. [But see 16 below.]
299    
300    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
301        Sheri Pierce.
302    
303    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
304        the first byte in a match must be "a".
305    
306    11. Change 17 for 8.13 increased the recursion depth for patterns like
307        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
308        pattern contains any instances of (*THEN). If it does not, the old
309        optimizations are restored. It would be nice to do this on a per-group
310        basis, but at the moment that is not feasible.
311    
312    12. In some environments, the output of pcretest -C is CRLF terminated. This
313        broke RunTest's code that checks for the link size. A single white space
314        character after the value is now allowed for.
315    
316    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
317        For "fr", it uses the Windows-specific input and output files.
318    
319    14. If (*THEN) appeared in a group that was called recursively or as a
320        subroutine, it did not work as intended. [But see next item.]
321    
322    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
323        pattern fragments (but not containing any | characters). If A and B are
324        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
325        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
326        D. In other words, Perl considers parentheses that do not contain any |
327        characters to be part of a surrounding alternative, whereas PCRE was
328        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
329        differently. PCRE now behaves in the same way as Perl, except in the case
330        of subroutine/recursion calls such as (?1) which have in any case always
331        been different (but PCRE had them first :-).
332    
333    16. Related to 15 above: Perl does not treat the | in a conditional group as
334        creating alternatives. Such a group is treated in the same way as an
335        ordinary group without any | characters when processing (*THEN). PCRE has
336        been changed to match Perl's behaviour.
337    
338    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
339        RunGrepTest script failed.
340    
341    18. Change 22 for version 13 caused atomic groups to use more stack. This is
342        inevitable for groups that contain captures, but it can lead to a lot of
343        stack use in large patterns. The old behaviour has been restored for atomic
344        groups that do not contain any capturing parentheses.
345    
346    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
347        suppress the check for a minimum subject length at run time. (If it was
348        given to pcre_exec() or pcre_dfa_exec() it did work.)
349    
350    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
351        fail to work when decoding hex characters in data strings in EBCDIC
352        environments.
353    
354    21. It appears that in at least one Mac OS environment, the isxdigit() function
355        is implemented as a macro that evaluates to its argument more than once,
356        contravening the C 90 Standard (I haven't checked a later standard). There
357        was an instance in pcretest which caused it to go wrong when processing
358        \x{...} escapes in subject strings. The has been rewritten to avoid using
359        things like p++ in the argument of isxdigit().
360    
361    
362  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
# Line 127  Version 8.13 16-Aug-2011 Line 456  Version 8.13 16-Aug-2011
456      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
457      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
458      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
459      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
460    
461  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
462      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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