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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    
41    Version 8.34 15-December-2013
42    -----------------------------
43    
44    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
45        executable memory. Patch inspired by Carsten Klein.
46    
47    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
48        this macro is never tested and has no effect, because the work to support
49        coverage involves only compiling and linking options and special targets in
50        the Makefile. The comment in config.h implied that defining the macro would
51        enable coverage support, which is totally false. There was also support for
52        setting this macro in the CMake files (my fault, I just copied it from
53        configure). SUPPORT_GCOV has now been removed.
54    
55    3.  Make a small performance improvement in strlen16() and strlen32() in
56        pcretest.
57    
58    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
59        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
60        these cases). There was also one in pcretest.c.
61    
62    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
63    
64    6.  In UTF mode, the code for checking whether a group could match an empty
65        string (which is used for indefinitely repeated groups to allow for
66        breaking an infinite loop) was broken when the group contained a repeated
67        negated single-character class with a character that occupied more than one
68        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
69        UTF-8 mode). The effect was undefined: the group might or might not be
70        deemed as matching an empty string, or the program might have crashed.
71    
72    7.  The code for checking whether a group could match an empty string was not
73        recognizing that \h, \H, \v, \V, and \R must match a character.
74    
75    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
76        an empty string. If it can, pcretest shows this in its information output.
77    
78    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
79        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
80        matched by pcre_exec() without using JIT:
81    
82        (a) If the rest of the pattern did not match after a maximal run of
83            grapheme clusters, the code for backing up to try with fewer of them
84            did not always back up over a full grapheme when characters that do not
85            have the modifier quality were involved, e.g. Hangul syllables.
86    
87        (b) If the match point in a subject started with modifier character, and
88            there was no match, the code could incorrectly back up beyond the match
89            point, and potentially beyond the first character in the subject,
90            leading to a segfault or an incorrect match result.
91    
92    10. A conditional group with an assertion condition could lead to PCRE
93        recording an incorrect first data item for a match if no other first data
94        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
95        first data item, and therefore matched "ca" after "c" instead of at the
96        start.
97    
98    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
99        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
100    
101    12. The source of pcregrep now includes z/OS-specific code so that it can be
102        compiled for z/OS as part of the special z/OS distribution.
103    
104    13. Added the -T and -TM options to pcretest.
105    
106    14. The code in pcre_compile.c for creating the table of named capturing groups
107        has been refactored. Instead of creating the table dynamically during the
108        actual compiling pass, the information is remembered during the pre-compile
109        pass (on the stack unless there are more than 20 named groups, in which
110        case malloc() is used) and the whole table is created before the actual
111        compile happens. This has simplified the code (it is now nearly 150 lines
112        shorter) and prepared the way for better handling of references to groups
113        with duplicate names.
114    
115    15. A back reference to a named subpattern when there is more than one of the
116        same name now checks them in the order in which they appear in the pattern.
117        The first one that is set is used for the reference. Previously only the
118        first one was inspected. This change makes PCRE more compatible with Perl.
119    
120    16. Unicode character properties were updated from Unicode 6.3.0.
121    
122    17. The compile-time code for auto-possessification has been refactored, based
123        on a patch by Zoltan Herczeg. It now happens after instead of during
124        compilation. The code is cleaner, and more cases are handled. The option
125        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
126        options in pcretest are provided to set it. It can also be set by
127        (*NO_AUTO_POSSESS) at the start of a pattern.
128    
129    18. The character VT has been added to the default ("C" locale) set of
130        characters that match \s and are generally treated as white space,
131        following this same change in Perl 5.18. There is now no difference between
132        "Perl space" and "POSIX space". Whether VT is treated as white space in
133        other locales depends on the locale.
134    
135    19. The code for checking named groups as conditions, either for being set or
136        for being recursed, has been refactored (this is related to 14 and 15
137        above). Processing unduplicated named groups should now be as fast at
138        numerical groups, and processing duplicated groups should be faster than
139        before.
140    
141    20. Two patches to the CMake build system, by Alexander Barkov:
142    
143          (1) Replace the "source" command by "." in CMakeLists.txt because
144              "source" is a bash-ism.
145    
146          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
147              without these the CMake build does not work on Solaris.
148    
149    21. Perl has changed its handling of \8 and \9. If there is no previously
150        encountered capturing group of those numbers, they are treated as the
151        literal characters 8 and 9 instead of a binary zero followed by the
152        literals. PCRE now does the same.
153    
154    22. Following Perl, added \o{} to specify codepoints in octal, making it
155        possible to specify values greater than 0777 and also making them
156        unambiguous.
157    
158    23. Perl now gives an error for missing closing braces after \x{... instead of
159        treating the string as literal. PCRE now does the same.
160    
161    24. RunTest used to grumble if an inappropriate test was selected explicitly,
162        but just skip it when running all tests. This make it awkward to run ranges
163        of tests when one of them was inappropriate. Now it just skips any
164        inappropriate tests, as it always did when running all tests.
165    
166    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
167        character types such as \d or \w, too many callouts were inserted, and the
168        data that they returned was rubbish.
169    
170    26. In UCP mode, \s was not matching two of the characters that Perl matches,
171        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
172        were matched by \h. The code has now been refactored so that the lists of
173        the horizontal and vertical whitespace characters used for \h and \v (which
174        are defined only in one place) are now also used for \s.
175    
176    27. Add JIT support for the 64 bit TileGX architecture.
177        Patch by Jiong Wang (Tilera Corporation).
178    
179    28. Possessive quantifiers for classes (both explicit and automatically
180        generated) now use special opcodes instead of wrapping in ONCE brackets.
181    
182    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
183        (because it's meaningless), this was not happening when PCRE_CASELESS was
184        set. Not wrong, but inefficient.
185    
186    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
187        properties for \w, \d, etc) is present in a test regex. Otherwise if the
188        test contains no characters greater than 255, Perl doesn't realise it
189        should be using Unicode semantics.
190    
191    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
192        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
193        does in Unicode mode.
194    
195    32. Added the "forbid" facility to pcretest so that putting tests into the
196        wrong test files can sometimes be quickly detected.
197    
198    33. There is now a limit (default 250) on the depth of nesting of parentheses.
199        This limit is imposed to control the amount of system stack used at compile
200        time. It can be changed at build time by --with-parens-nest-limit=xxx or
201        the equivalent in CMake.
202    
203    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
204        errors. Perl warns for these when in warning mode, but PCRE has no facility
205        for giving warnings.
206    
207    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
208        However, this was not working for (?!) because it is optimized to (*FAIL),
209        for which PCRE does not allow quantifiers. The optimization is now disabled
210        when a quantifier follows (?!). I can't see any use for this, but it makes
211        things uniform.
212    
213    36. Perl no longer allows group names to start with digits, so I have made this
214        change also in PCRE. It simplifies the code a bit.
215    
216    37. In extended mode, Perl ignores spaces before a + that indicates a
217        possessive quantifier. PCRE allowed a space before the quantifier, but not
218        before the possessive +. It now does.
219    
220    38. The use of \K (reset reported match start) within a repeated possessive
221        group such as (a\Kb)*+ was not working.
222    
223    40. Document that the same character tables must be used at compile time and
224        run time, and that the facility to pass tables to pcre_exec() and
225        pcre_dfa_exec() is for use only with saved/restored patterns.
226    
227    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
228        features for Builds with MSVC:
229    
230        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
231           builds). The .rc files can be used to set FileDescription and many other
232           attributes.
233    
234        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
235           This allows higher-level build scripts which want .pdb files to avoid
236           hard-coding the exact files needed."
237    
238    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
239        mean "start of word" and "end of word", respectively, as a transition aid.
240    
241    43. A minimizing repeat of a class containing codepoints greater than 255 in
242        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
243        compiled to use the heap for recursion.
244    
245    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
246        is configured.
247    
248    
249    Version 8.33 28-May-2013
250    ------------------------
251    
252  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
253      avoid compiler signed/unsigned warnings. Added (int) casts to unsigned      avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
254      variables that are added to signed variables, to ensure the result is      variables that are added to signed variables, to ensure the result is
255      signed and can be negated.      signed and can be negated.
256    
257  2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the  2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
258      CMake config files.      CMake config files.
259    
260  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
261      #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes      #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
262      overriding via -D on the command line possible.      overriding via -D on the command line possible.
263    
264  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
265      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
266      a specific Windows environment. Testing on Linux did also appear to show      a specific Windows environment. Testing on Linux did also appear to show
267      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
268      Xop which should be unsigned.      Xop which should be unsigned.
269    
270  5.  Related to (4), changing the definition of the intermediate variable cc  5.  Related to (4), changing the definition of the intermediate variable cc
271      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
272      improvements.      improvements.
273    
274    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
275        unnecessary spaces.
276    
277    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
278        and later.
279    
280    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
281    
282    9.  Optimizing fast_forward_start_bits in JIT.
283    
284    10. Adding support for callouts in JIT, and fixing some issues revealed
285        during this work. Namely:
286    
287        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
288    
289        (b) Minimum length was not checked before the matching is started.
290    
291    11. The value of capture_last that is passed to callouts was incorrect in some
292        cases when there was a capture on one path that was subsequently abandoned
293        after a backtrack. Also, the capture_last value is now reset after a
294        recursion, since all captures are also reset in this case.
295    
296    12. The interpreter no longer returns the "too many substrings" error in the
297        case when an overflowing capture is in a branch that is subsequently
298        abandoned after a backtrack.
299    
300    13. In the pathological case when an offset vector of size 2 is used, pcretest
301        now prints out the matched string after a yield of 0 or 1.
302    
303    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
304        Only supported by the JIT compiler at the moment.
305    
306    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
307    
308    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
309        offset of the starting point of the matching process, provided the offsets
310        vector is large enough.
311    
312    17. The \A escape now records a lookbehind value of 1, though its execution
313        does not actually inspect the previous character. This is to ensure that,
314        in partial multi-segment matching, at least one character from the old
315        segment is retained when a new segment is processed. Otherwise, if there
316        are no lookbehinds in the pattern, \A might match incorrectly at the start
317        of a new segment.
318    
319    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
320    
321    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
322        gives some modest performance improvement in 8-bit mode.
323    
324    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
325        be expressed in certain programming languages using Universal Character
326        Names.
327    
328    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
329        which points out that "non characters" are not "characters that may not
330        appear in Unicode strings" but rather "characters that are reserved for
331        internal use and have only local meaning".
332    
333    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
334        there was a conditional group that depended on an assertion, if the
335        assertion was false, the callout that immediately followed the alternation
336        in the condition was skipped when pcre_exec() was used for matching.
337    
338    23. Allow an explicit callout to be inserted before an assertion that is the
339        condition for a conditional group, for compatibility with automatic
340        callouts, which always insert a callout at this point.
341    
342    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
343        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
344    
345    25. (*PRUNE) is now supported by the JIT compiler.
346    
347    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
348    
349    27. Fix the case where there are two or more SKIPs with arguments that may be
350        ignored.
351    
352    28. (*SKIP) is now supported by the JIT compiler.
353    
354    29. (*THEN) is now supported by the JIT compiler.
355    
356    30. Update RunTest with additional test selector options.
357    
358    31. The way PCRE handles backtracking verbs has been changed in two ways.
359    
360        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
361        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
362        backtracking. In some cases this makes it more Perl-compatible, but Perl's
363        rather obscure rules do not always do the same thing.
364    
365        (2) Previously, backtracking verbs were confined within assertions. This is
366        no longer the case for positive assertions, except for (*ACCEPT). Again,
367        this sometimes improves Perl compatibility, and sometimes does not.
368    
369    32. A number of tests that were in test 2 because Perl did things differently
370        have been moved to test 1, because either Perl or PCRE has changed, and
371        these tests are now compatible.
372    
373    32. Backtracking control verbs are now handled in the same way in JIT and
374        interpreter.
375    
376    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
377        contained a forward subroutine reference caused a compile error.
378    
379    34. Auto-detect and optimize limited repetitions in JIT.
380    
381    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
382        blocking (*UTF) etc.
383    
384    36. In the interpreter, maximizing pattern repetitions for characters and
385        character types now use tail recursion, which reduces stack usage.
386    
387    37. The value of the max lookbehind was not correctly preserved if a compiled
388        and saved regex was reloaded on a host of different endianness.
389    
390    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
391        of the compiled pattern block, expand the flags field from 16 to 32 bits
392        because it was almost full.
393    
394    39. Try madvise first before posix_madvise.
395    
396    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
397        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
398        original change locked out all matches of empty strings. This has been
399        changed so that one match of an empty string per line is recognized.
400        Subsequent searches on the same line (for colouring or for --only-matching,
401        for example) do not recognize empty strings.
402    
403    41. Applied a user patch to fix a number of spelling mistakes in comments.
404    
405    42. Data lines longer than 65536 caused pcretest to crash.
406    
407    43. Clarified the data type for length and startoffset arguments for pcre_exec
408        and pcre_dfa_exec in the function-specific man pages, where they were
409        explicitly stated to be in bytes, never having been updated. I also added
410        some clarification to the pcreapi man page.
411    
412    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
413        a segmentation fault.
414    
415    
416  Version 8.32 30-November-2012  Version 8.32 30-November-2012
417  -----------------------------  -----------------------------
# Line 1534  Version 7.9 11-Apr-09 Line 1920  Version 7.9 11-Apr-09
1920  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
1921      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
1922      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1923      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
1924        8.33.]
1925    
1926  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
1927      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 1777  Version 7.7 07-May-08 Line 2164  Version 7.7 07-May-08
2164      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2165      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2166      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2167      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2168      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2169      was subsequently set up correctly.)      was subsequently set up correctly.)
2170    

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