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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.33 xx-xxxx-201x  Version 8.35-RC1 xx-xxxx-201x
5  -------------------------  -----------------------------
6    
7    1.  A new flag is set, when property checks are present in an XCLASS.
8        When this flag is not set, PCRE can perform certain optimizations
9        such as studying these XCLASS-es.
10    
11    2.  The auto-possessification of character sets were improved: a normal
12        and an extended character set can be compared now. Furthermore
13        the JIT compiler optimizes more character set checks.
14    
15    3.  Got rid of some compiler warnings for potentially uninitialized variables
16        that show up only when compiled with -O2.
17    
18    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
19        of a match later then the end of the match. The pcretest program was not
20        handling the case sensibly - it was outputting from the start to the next
21        binary zero. It now reports this situation in a message, and outputs the
22        text from the end to the start.
23    
24    5.  Fast forward search is improved in JIT. Instead of the first three
25        characters, any three characters with fixed position can be searched.
26        Search order: first, last, middle.
27    
28    6.  Improve character range checks in JIT. Characters are read by an inprecise
29        function now, which returns with an unknown value if the character code is
30        above a certain treshold (e.g: 256). The only limitation is that the value
31        must be bigger than the treshold as well. This function is useful, when
32        the characters above the treshold are handled in the same way.
33    
34    7.  The macros whose names start with RAWUCHAR are placeholders for a future
35        mode in which only the bottom 21 bits of 32-bit data items are used. To
36        make this more memorable for those maintaining the code, the names have
37        been changed to start with UCHAR21, and an extensive comment has been added
38        to their definition.
39    
40    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
41        to the export list in Makefile.am (they were accidentally omitted from the
42        8.34 tarball).
43    
44    9.  The informational output from pcretest used the phrase "starting byte set"
45        which is inappropriate for the 16-bit and 32-bit libraries. As the output
46        for "first char" and "need char" really means "non-UTF-char", I've changed
47        "byte" to "char", and slightly reworded the output. The documentation about
48        these values has also been (I hope) clarified.
49    
50    10. Another JIT related optimization: use table jumps for selecting the correct
51        backtracking path, when more than four alternatives are present inside a
52        bracket.
53    
54    
55    Version 8.34 15-December-2013
56    -----------------------------
57    
58    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
59        executable memory. Patch inspired by Carsten Klein.
60    
61    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
62        this macro is never tested and has no effect, because the work to support
63        coverage involves only compiling and linking options and special targets in
64        the Makefile. The comment in config.h implied that defining the macro would
65        enable coverage support, which is totally false. There was also support for
66        setting this macro in the CMake files (my fault, I just copied it from
67        configure). SUPPORT_GCOV has now been removed.
68    
69    3.  Make a small performance improvement in strlen16() and strlen32() in
70        pcretest.
71    
72    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
73        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
74        these cases). There was also one in pcretest.c.
75    
76    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
77    
78    6.  In UTF mode, the code for checking whether a group could match an empty
79        string (which is used for indefinitely repeated groups to allow for
80        breaking an infinite loop) was broken when the group contained a repeated
81        negated single-character class with a character that occupied more than one
82        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
83        UTF-8 mode). The effect was undefined: the group might or might not be
84        deemed as matching an empty string, or the program might have crashed.
85    
86    7.  The code for checking whether a group could match an empty string was not
87        recognizing that \h, \H, \v, \V, and \R must match a character.
88    
89    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
90        an empty string. If it can, pcretest shows this in its information output.
91    
92    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
93        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
94        matched by pcre_exec() without using JIT:
95    
96        (a) If the rest of the pattern did not match after a maximal run of
97            grapheme clusters, the code for backing up to try with fewer of them
98            did not always back up over a full grapheme when characters that do not
99            have the modifier quality were involved, e.g. Hangul syllables.
100    
101        (b) If the match point in a subject started with modifier character, and
102            there was no match, the code could incorrectly back up beyond the match
103            point, and potentially beyond the first character in the subject,
104            leading to a segfault or an incorrect match result.
105    
106    10. A conditional group with an assertion condition could lead to PCRE
107        recording an incorrect first data item for a match if no other first data
108        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
109        first data item, and therefore matched "ca" after "c" instead of at the
110        start.
111    
112    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
113        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
114    
115    12. The source of pcregrep now includes z/OS-specific code so that it can be
116        compiled for z/OS as part of the special z/OS distribution.
117    
118    13. Added the -T and -TM options to pcretest.
119    
120    14. The code in pcre_compile.c for creating the table of named capturing groups
121        has been refactored. Instead of creating the table dynamically during the
122        actual compiling pass, the information is remembered during the pre-compile
123        pass (on the stack unless there are more than 20 named groups, in which
124        case malloc() is used) and the whole table is created before the actual
125        compile happens. This has simplified the code (it is now nearly 150 lines
126        shorter) and prepared the way for better handling of references to groups
127        with duplicate names.
128    
129    15. A back reference to a named subpattern when there is more than one of the
130        same name now checks them in the order in which they appear in the pattern.
131        The first one that is set is used for the reference. Previously only the
132        first one was inspected. This change makes PCRE more compatible with Perl.
133    
134    16. Unicode character properties were updated from Unicode 6.3.0.
135    
136    17. The compile-time code for auto-possessification has been refactored, based
137        on a patch by Zoltan Herczeg. It now happens after instead of during
138        compilation. The code is cleaner, and more cases are handled. The option
139        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
140        options in pcretest are provided to set it. It can also be set by
141        (*NO_AUTO_POSSESS) at the start of a pattern.
142    
143    18. The character VT has been added to the default ("C" locale) set of
144        characters that match \s and are generally treated as white space,
145        following this same change in Perl 5.18. There is now no difference between
146        "Perl space" and "POSIX space". Whether VT is treated as white space in
147        other locales depends on the locale.
148    
149    19. The code for checking named groups as conditions, either for being set or
150        for being recursed, has been refactored (this is related to 14 and 15
151        above). Processing unduplicated named groups should now be as fast at
152        numerical groups, and processing duplicated groups should be faster than
153        before.
154    
155    20. Two patches to the CMake build system, by Alexander Barkov:
156    
157          (1) Replace the "source" command by "." in CMakeLists.txt because
158              "source" is a bash-ism.
159    
160          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
161              without these the CMake build does not work on Solaris.
162    
163    21. Perl has changed its handling of \8 and \9. If there is no previously
164        encountered capturing group of those numbers, they are treated as the
165        literal characters 8 and 9 instead of a binary zero followed by the
166        literals. PCRE now does the same.
167    
168    22. Following Perl, added \o{} to specify codepoints in octal, making it
169        possible to specify values greater than 0777 and also making them
170        unambiguous.
171    
172    23. Perl now gives an error for missing closing braces after \x{... instead of
173        treating the string as literal. PCRE now does the same.
174    
175    24. RunTest used to grumble if an inappropriate test was selected explicitly,
176        but just skip it when running all tests. This make it awkward to run ranges
177        of tests when one of them was inappropriate. Now it just skips any
178        inappropriate tests, as it always did when running all tests.
179    
180    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
181        character types such as \d or \w, too many callouts were inserted, and the
182        data that they returned was rubbish.
183    
184    26. In UCP mode, \s was not matching two of the characters that Perl matches,
185        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
186        were matched by \h. The code has now been refactored so that the lists of
187        the horizontal and vertical whitespace characters used for \h and \v (which
188        are defined only in one place) are now also used for \s.
189    
190    27. Add JIT support for the 64 bit TileGX architecture.
191        Patch by Jiong Wang (Tilera Corporation).
192    
193    28. Possessive quantifiers for classes (both explicit and automatically
194        generated) now use special opcodes instead of wrapping in ONCE brackets.
195    
196    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
197        (because it's meaningless), this was not happening when PCRE_CASELESS was
198        set. Not wrong, but inefficient.
199    
200    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
201        properties for \w, \d, etc) is present in a test regex. Otherwise if the
202        test contains no characters greater than 255, Perl doesn't realise it
203        should be using Unicode semantics.
204    
205    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
206        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
207        does in Unicode mode.
208    
209    32. Added the "forbid" facility to pcretest so that putting tests into the
210        wrong test files can sometimes be quickly detected.
211    
212    33. There is now a limit (default 250) on the depth of nesting of parentheses.
213        This limit is imposed to control the amount of system stack used at compile
214        time. It can be changed at build time by --with-parens-nest-limit=xxx or
215        the equivalent in CMake.
216    
217    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
218        errors. Perl warns for these when in warning mode, but PCRE has no facility
219        for giving warnings.
220    
221    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
222        However, this was not working for (?!) because it is optimized to (*FAIL),
223        for which PCRE does not allow quantifiers. The optimization is now disabled
224        when a quantifier follows (?!). I can't see any use for this, but it makes
225        things uniform.
226    
227    36. Perl no longer allows group names to start with digits, so I have made this
228        change also in PCRE. It simplifies the code a bit.
229    
230    37. In extended mode, Perl ignores spaces before a + that indicates a
231        possessive quantifier. PCRE allowed a space before the quantifier, but not
232        before the possessive +. It now does.
233    
234    38. The use of \K (reset reported match start) within a repeated possessive
235        group such as (a\Kb)*+ was not working.
236    
237    40. Document that the same character tables must be used at compile time and
238        run time, and that the facility to pass tables to pcre_exec() and
239        pcre_dfa_exec() is for use only with saved/restored patterns.
240    
241    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
242        features for Builds with MSVC:
243    
244        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
245           builds). The .rc files can be used to set FileDescription and many other
246           attributes.
247    
248        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
249           This allows higher-level build scripts which want .pdb files to avoid
250           hard-coding the exact files needed."
251    
252    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
253        mean "start of word" and "end of word", respectively, as a transition aid.
254    
255    43. A minimizing repeat of a class containing codepoints greater than 255 in
256        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
257        compiled to use the heap for recursion.
258    
259    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
260        is configured.
261    
262    
263    Version 8.33 28-May-2013
264    ------------------------
265    
266  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
267      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 273  Version 8.33 xx-xxxx-201x
273    
274  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
275      #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes      #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
276      overriding via -D on the command line possible.      overriding via -D on the command line possible.
277    
278  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
279      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
280      a specific Windows environment. Testing on Linux did also appear to show      a specific Windows environment. Testing on Linux did also appear to show
281      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
282      Xop which should be unsigned.      Xop which should be unsigned.
283    
284  5.  Related to (4), changing the definition of the intermediate variable cc  5.  Related to (4), changing the definition of the intermediate variable cc
285      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 287  Version 8.33 xx-xxxx-201x
287    
288  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
289      unnecessary spaces.      unnecessary spaces.
290    
291  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
292      and later.      and later.
293    
294  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.
295    
296  9.  Optimizing fast_forward_start_bits in JIT.  9.  Optimizing fast_forward_start_bits in JIT.
297    
298  10. Adding experimental support for callouts in JIT, and fixing some  10. Adding support for callouts in JIT, and fixing some issues revealed
299      issues revealed during this work. Namely:      during this work. Namely:
300    
301      (a) Unoptimized capturing brackets incorrectly reset on backtrack.      (a) Unoptimized capturing brackets incorrectly reset on backtrack.
302    
303      (b) Minimum length was not checked before the matching is started.      (b) Minimum length was not checked before the matching is started.
304    
305  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
306      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
307      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
308      recursion, since all captures are also reset in this case.      recursion, since all captures are also reset in this case.
309    
310  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
311      case when an overflowing capture is in a branch that is subsequently      case when an overflowing capture is in a branch that is subsequently
312      abandoned after a backtrack.      abandoned after a backtrack.
313    
314  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
315      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.
316    
317  14. Inlining subpatterns in recursions, when certain conditions are fulfilled.  14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
# Line 61  Version 8.33 xx-xxxx-201x Line 320  Version 8.33 xx-xxxx-201x
320  15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.  15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
321    
322  16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the  16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
323      offset of the starting point of the matching process, provided the offsets      offset of the starting point of the matching process, provided the offsets
324      vector is large enough.      vector is large enough.
325    
326  17. The \A escape now records a lookbehind value of 1, though its execution  17. The \A escape now records a lookbehind value of 1, though its execution
327      does not actually inspect the previous character. This is to ensure that,      does not actually inspect the previous character. This is to ensure that,
328      in partial multi-segment matching, at least one character from the old      in partial multi-segment matching, at least one character from the old
# Line 71  Version 8.33 xx-xxxx-201x Line 330  Version 8.33 xx-xxxx-201x
330      are no lookbehinds in the pattern, \A might match incorrectly at the start      are no lookbehinds in the pattern, \A might match incorrectly at the start
331      of a new segment.      of a new segment.
332    
333    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
334    
335    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
336        gives some modest performance improvement in 8-bit mode.
337    
338    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
339        be expressed in certain programming languages using Universal Character
340        Names.
341    
342    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
343        which points out that "non characters" are not "characters that may not
344        appear in Unicode strings" but rather "characters that are reserved for
345        internal use and have only local meaning".
346    
347    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
348        there was a conditional group that depended on an assertion, if the
349        assertion was false, the callout that immediately followed the alternation
350        in the condition was skipped when pcre_exec() was used for matching.
351    
352    23. Allow an explicit callout to be inserted before an assertion that is the
353        condition for a conditional group, for compatibility with automatic
354        callouts, which always insert a callout at this point.
355    
356    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
357        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
358    
359    25. (*PRUNE) is now supported by the JIT compiler.
360    
361    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
362    
363    27. Fix the case where there are two or more SKIPs with arguments that may be
364        ignored.
365    
366    28. (*SKIP) is now supported by the JIT compiler.
367    
368    29. (*THEN) is now supported by the JIT compiler.
369    
370    30. Update RunTest with additional test selector options.
371    
372    31. The way PCRE handles backtracking verbs has been changed in two ways.
373    
374        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
375        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
376        backtracking. In some cases this makes it more Perl-compatible, but Perl's
377        rather obscure rules do not always do the same thing.
378    
379        (2) Previously, backtracking verbs were confined within assertions. This is
380        no longer the case for positive assertions, except for (*ACCEPT). Again,
381        this sometimes improves Perl compatibility, and sometimes does not.
382    
383    32. A number of tests that were in test 2 because Perl did things differently
384        have been moved to test 1, because either Perl or PCRE has changed, and
385        these tests are now compatible.
386    
387    32. Backtracking control verbs are now handled in the same way in JIT and
388        interpreter.
389    
390    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
391        contained a forward subroutine reference caused a compile error.
392    
393    34. Auto-detect and optimize limited repetitions in JIT.
394    
395    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
396        blocking (*UTF) etc.
397    
398    36. In the interpreter, maximizing pattern repetitions for characters and
399        character types now use tail recursion, which reduces stack usage.
400    
401    37. The value of the max lookbehind was not correctly preserved if a compiled
402        and saved regex was reloaded on a host of different endianness.
403    
404    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
405        of the compiled pattern block, expand the flags field from 16 to 32 bits
406        because it was almost full.
407    
408    39. Try madvise first before posix_madvise.
409    
410    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
411        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
412        original change locked out all matches of empty strings. This has been
413        changed so that one match of an empty string per line is recognized.
414        Subsequent searches on the same line (for colouring or for --only-matching,
415        for example) do not recognize empty strings.
416    
417    41. Applied a user patch to fix a number of spelling mistakes in comments.
418    
419    42. Data lines longer than 65536 caused pcretest to crash.
420    
421    43. Clarified the data type for length and startoffset arguments for pcre_exec
422        and pcre_dfa_exec in the function-specific man pages, where they were
423        explicitly stated to be in bytes, never having been updated. I also added
424        some clarification to the pcreapi man page.
425    
426    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
427        a segmentation fault.
428    
429    
430  Version 8.32 30-November-2012  Version 8.32 30-November-2012
431  -----------------------------  -----------------------------
# Line 1579  Version 7.9 11-Apr-09 Line 1934  Version 7.9 11-Apr-09
1934  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
1935      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
1936      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1937      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1938        8.33.]
1939    
1940  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
1941      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 1822  Version 7.7 07-May-08 Line 2178  Version 7.7 07-May-08
2178      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2179      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2180      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2181      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2182      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2183      was subsequently set up correctly.)      was subsequently set up correctly.)
2184    

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