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revision 1249 by zherczeg, Mon Feb 18 09:55:43 2013 UTC revision 1354 by ph10, Mon Aug 12 14:31:07 2013 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.33 xx-xxxx-201x  Version 8.34 xx-xxxx-201x
5  -------------------------  --------------------------
6    
7    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
8        executable memory. Patch inspired by Carsten Klein.
9    
10    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
11        this macro is never tested and has no effect, because the work to support
12        coverage involves only compiling and linking options and special targets in
13        the Makefile. The comment in config.h implied that defining the macro would
14        enable coverage support, which is totally false. There was also support for
15        setting this macro in the CMake files (my fault, I just copied it from
16        configure). SUPPORT_GCOV has now been removed.
17    
18    3.  Make a small performance improvement in strlen16() and strlen32() in
19        pcretest.
20    
21    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
22        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
23        these cases). There was also one in pcretest.c.
24    
25    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
26    
27    6.  In UTF mode, the code for checking whether a group could match an empty
28        string (which is used for indefinitely repeated groups to allow for
29        breaking an infinite loop) was broken when the group contained a repeated
30        negated single-character class with a character that occupied more than one
31        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
32        UTF-8 mode). The effect was undefined: the group might or might not be
33        deemed as matching an empty string, or the program might have crashed.
34    
35    7.  The code for checking whether a group could match an empty string was not
36        recognizing that \h, \H, \v, \V, and \R must match a character.
37    
38    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
39        an empty string. If it can, pcretest shows this in its information output.
40    
41    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
42        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
43        matched by pcre_exec() without using JIT:
44    
45        (a) If the rest of the pattern did not match after a maximal run of
46            grapheme clusters, the code for backing up to try with fewer of them
47            did not always back up over a full grapheme when characters that do not
48            have the modifier quality were involved, e.g. Hangul syllables.
49    
50        (b) If the match point in a subject started with modifier character, and
51            there was no match, the code could incorrectly back up beyond the match
52            point, and potentially beyond the first character in the subject,
53            leading to a segfault or an incorrect match result.
54    
55    10. A conditional group with an assertion condition could lead to PCRE
56        recording an incorrect first data item for a match if no other firse data
57        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
58        first data item, and therefore matched "ca" after "c" instead of at the
59        start.
60    
61    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
62        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
63    
64    12. The source of pcregrep now includes z/OS-specific code so that it can be
65        compiled for z/OS as part of the special z/OS distribution.
66    
67    
68    Version 8.33 28-May-2013
69    ------------------------
70    
71  1.  Added 'U' to some constants that are compared to unsigned integers, to  1.  Added 'U' to some constants that are compared to unsigned integers, to
72      avoid compiler signed/unsigned warnings. Added (int) casts to unsigned      avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
# Line 14  Version 8.33 xx-xxxx-201x Line 78  Version 8.33 xx-xxxx-201x
78    
79  3.  Revise the creation of config.h.generic so that all boolean macros are  3.  Revise the creation of config.h.generic so that all boolean macros are
80      #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes      #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
81      overriding via -D on the command line possible.      overriding via -D on the command line possible.
82    
83  4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar  4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
84      to unsigned int is reported to make a quite noticeable speed difference in      to unsigned int is reported to make a quite noticeable speed difference in
85      a specific Windows environment. Testing on Linux did also appear to show      a specific Windows environment. Testing on Linux did also appear to show
86      some benefit (and it is clearly not harmful). Also fixed the definition of      some benefit (and it is clearly not harmful). Also fixed the definition of
87      Xop which should be unsigned.      Xop which should be unsigned.
88    
89  5.  Related to (4), changing the definition of the intermediate variable cc  5.  Related to (4), changing the definition of the intermediate variable cc
90      in repeated character loops from pcre_uchar to pcre_uint32 also gave speed      in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
# Line 28  Version 8.33 xx-xxxx-201x Line 92  Version 8.33 xx-xxxx-201x
92    
93  6.  Fix forward search in JIT when link size is 3 or greater. Also removed some  6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
94      unnecessary spaces.      unnecessary spaces.
95    
96  7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12  7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
97      and later.      and later.
98    
99  8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.  8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
100    
101  9.  Optimizing fast_forward_start_bits in JIT.  9.  Optimizing fast_forward_start_bits in JIT.
102    
103  10. Adding experimental support for callouts in JIT, and fixing some  10. Adding support for callouts in JIT, and fixing some issues revealed
104      issues revealed during this work. Namely:      during this work. Namely:
105    
106      (a) Unoptimized capturing brackets incorrectly reset on backtrack.      (a) Unoptimized capturing brackets incorrectly reset on backtrack.
107    
108      (b) Minimum length was not checked before the matching is started.      (b) Minimum length was not checked before the matching is started.
109    
110  11. The value of capture_last that is passed to callouts was incorrect in some  11. The value of capture_last that is passed to callouts was incorrect in some
111      cases when there was a capture on one path that was subsequently abandoned      cases when there was a capture on one path that was subsequently abandoned
112      after a backtrack. Also, the capture_last value is now reset after a      after a backtrack. Also, the capture_last value is now reset after a
113      recursion, since all captures are also reset in this case.      recursion, since all captures are also reset in this case.
114    
115  12. The interpreter no longer returns the "too many substrings" error in the  12. The interpreter no longer returns the "too many substrings" error in the
116      case when an overflowing capture is in a branch that is subsequently      case when an overflowing capture is in a branch that is subsequently
117      abandoned after a backtrack.      abandoned after a backtrack.
118    
119  13. In the pathological case when an offset vector of size 2 is used, pcretest  13. In the pathological case when an offset vector of size 2 is used, pcretest
120      now prints out the matched string after a yield of 0 or 1.      now prints out the matched string after a yield of 0 or 1.
121    
122  14. Inlining subpatterns in recursions, when certain conditions are fulfilled.  14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
123      Only supported by the JIT compiler at the moment.      Only supported by the JIT compiler at the moment.
124    
125    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
126    
127    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
128        offset of the starting point of the matching process, provided the offsets
129        vector is large enough.
130    
131    17. The \A escape now records a lookbehind value of 1, though its execution
132        does not actually inspect the previous character. This is to ensure that,
133        in partial multi-segment matching, at least one character from the old
134        segment is retained when a new segment is processed. Otherwise, if there
135        are no lookbehinds in the pattern, \A might match incorrectly at the start
136        of a new segment.
137    
138    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
139    
140    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
141        gives some modest performance improvement in 8-bit mode.
142    
143    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
144        be expressed in certain programming languages using Universal Character
145        Names.
146    
147    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
148        which points out that "non characters" are not "characters that may not
149        appear in Unicode strings" but rather "characters that are reserved for
150        internal use and have only local meaning".
151    
152    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
153        there was a conditional group that depended on an assertion, if the
154        assertion was false, the callout that immediately followed the alternation
155        in the condition was skipped when pcre_exec() was used for matching.
156    
157    23. Allow an explicit callout to be inserted before an assertion that is the
158        condition for a conditional group, for compatibility with automatic
159        callouts, which always insert a callout at this point.
160    
161    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
162        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
163    
164    25. (*PRUNE) is now supported by the JIT compiler.
165    
166    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
167    
168    27. Fix the case where there are two or more SKIPs with arguments that may be
169        ignored.
170    
171    28. (*SKIP) is now supported by the JIT compiler.
172    
173    29. (*THEN) is now supported by the JIT compiler.
174    
175    30. Update RunTest with additional test selector options.
176    
177    31. The way PCRE handles backtracking verbs has been changed in two ways.
178    
179        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
180        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
181        backtracking. In some cases this makes it more Perl-compatible, but Perl's
182        rather obscure rules do not always do the same thing.
183    
184        (2) Previously, backtracking verbs were confined within assertions. This is
185        no longer the case for positive assertions, except for (*ACCEPT). Again,
186        this sometimes improves Perl compatibility, and sometimes does not.
187    
188    32. A number of tests that were in test 2 because Perl did things differently
189        have been moved to test 1, because either Perl or PCRE has changed, and
190        these tests are now compatible.
191    
192    32. Backtracking control verbs are now handled in the same way in JIT and
193        interpreter.
194    
195    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
196        contained a forward subroutine reference caused a compile error.
197    
198    34. Auto-detect and optimize limited repetitions in JIT.
199    
200    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
201        blocking (*UTF) etc.
202    
203    36. In the interpreter, maximizing pattern repetitions for characters and
204        character types now use tail recursion, which reduces stack usage.
205    
206    37. The value of the max lookbehind was not correctly preserved if a compiled
207        and saved regex was reloaded on a host of different endianness.
208    
209    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
210        of the compiled pattern block, expand the flags field from 16 to 32 bits
211        because it was almost full.
212    
213    39. Try madvise first before posix_madvise.
214    
215    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
216        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
217        original change locked out all matches of empty strings. This has been
218        changed so that one match of an empty string per line is recognized.
219        Subsequent searches on the same line (for colouring or for --only-matching,
220        for example) do not recognize empty strings.
221    
222    41. Applied a user patch to fix a number of spelling mistakes in comments.
223    
224    42. Data lines longer than 65536 caused pcretest to crash.
225    
226    43. Clarified the data type for length and startoffset arguments for pcre_exec
227        and pcre_dfa_exec in the function-specific man pages, where they were
228        explicitly stated to be in bytes, never having been updated. I also added
229        some clarification to the pcreapi man page.
230    
231    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
232        a segmentation fault.
233    
234    
235  Version 8.32 30-November-2012  Version 8.32 30-November-2012
236  -----------------------------  -----------------------------
# Line 1566  Version 7.9 11-Apr-09 Line 1739  Version 7.9 11-Apr-09
1739  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
1740      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
1741      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1742      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1743        8.33.]
1744    
1745  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1746      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 1809  Version 7.7 07-May-08 Line 1983  Version 7.7 07-May-08
1983      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
1984      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
1985      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
1986      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
1987      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
1988      was subsequently set up correctly.)      was subsequently set up correctly.)
1989    

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