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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.33 28-April-2013  Version 8.36 xx-xxx-2014
5    ------------------------
7    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
8        -Wmissing-field-initializers and -Wunused-parameter.
10    2.  The tests for quantifiers being too big (greater than 65535) were being
11        applied after reading the number, and stupidly assuming that integer
12        overflow would give a negative number. The tests are now applied as the
13        numbers are read.
15    3.  Tidy code in pcre_exec.c where two branches that used to be different are
16        now the same.
18    4.  The JIT compiler did not generate match limit checks for certain
19        bracketed expressions with quantifiers. This may lead to exponential
20        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
21        issue should be resolved now.
23    5.  Fixed an issue, which occures when nested alternatives are optimized
24        with table jumps.
26    6.  Inserted two casts and changed some ints to size_t in the light of some
27        reported 64-bit compiler warnings (Bugzilla 1477).
29    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
30        an empty string, which sometimes were behaving incorrectly in the
31        interpreter (though correctly in the JIT matcher). This pcretest input is
32        an example:
34          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
37        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
38        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
39        for an empty string was breaking the inner loop and carrying on at a lower
40        level, when possessive repeated groups should always return to a higher
41        level as they have no backtrack points in them. The empty string test now
42        occurs at the outer level.
44    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
45        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
47    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
48        doesn't).
50    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
51        to hold a pattern to be incorrectly computed (too small) when there were
52        named back references to duplicated names. This could cause "internal
53        error: code overflow" or "double free or corruption" or other memory
54        handling errors.
56    11. When named subpatterns had the same prefixes, back references could be
57        confused. For example, in this pattern:
59          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
61        the reference to 'Name' was incorrectly treated as a reference to a
62        duplicate name.
64    12. A pattern such as /^s?c/mi8 where the optional character has more than
65        one "other case" was incorrectly compiled such that it would only try to
66        match starting at "c".
68    13. When a pattern starting with \s was studied, VT was not included in the
69        list of possible starting characters; this should have been part of the
70        8.34/18 patch.
72    14. If a character class started [\Qx]... where x is any character, the class
73        was incorrectly terminated at the ].
75    15. If a pattern that started with a caseless match for a character with more
76        than one "other case" was studied, PCRE did not set up the starting code
77        unit bit map for the list of possible characters. Now it does. This is an
78        optimization improvement, not a bug fix.
80    16. The Unicode data tables have been updated to Unicode 7.0.0.
82    17. Fixed a number of memory leaks in pcregrep.
84    18. Avoid a compiler warning (from some compilers) for a function call with
85        a cast that removes "const" from an lvalue by using an intermediate
86        variable (to which the compiler does not object).
88    19. Incorrect code was compiled if a group that contained an internal recursive
89        back reference was optional (had quantifier with a minimum of zero). This
90        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
91        caused segmentation faults because of stack overflows at compile time.
94    Version 8.35 04-April-2014
95  --------------------------  --------------------------
97    1.  A new flag is set, when property checks are present in an XCLASS.
98        When this flag is not set, PCRE can perform certain optimizations
99        such as studying these XCLASS-es.
101    2.  The auto-possessification of character sets were improved: a normal
102        and an extended character set can be compared now. Furthermore
103        the JIT compiler optimizes more character set checks.
105    3.  Got rid of some compiler warnings for potentially uninitialized variables
106        that show up only when compiled with -O2.
108    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
109        of a match later then the end of the match. The pcretest program was not
110        handling the case sensibly - it was outputting from the start to the next
111        binary zero. It now reports this situation in a message, and outputs the
112        text from the end to the start.
114    5.  Fast forward search is improved in JIT. Instead of the first three
115        characters, any three characters with fixed position can be searched.
116        Search order: first, last, middle.
118    6.  Improve character range checks in JIT. Characters are read by an inprecise
119        function now, which returns with an unknown value if the character code is
120        above a certain treshold (e.g: 256). The only limitation is that the value
121        must be bigger than the treshold as well. This function is useful, when
122        the characters above the treshold are handled in the same way.
124    7.  The macros whose names start with RAWUCHAR are placeholders for a future
125        mode in which only the bottom 21 bits of 32-bit data items are used. To
126        make this more memorable for those maintaining the code, the names have
127        been changed to start with UCHAR21, and an extensive comment has been added
128        to their definition.
130    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
131        to the export list in Makefile.am (they were accidentally omitted from the
132        8.34 tarball).
134    9.  The informational output from pcretest used the phrase "starting byte set"
135        which is inappropriate for the 16-bit and 32-bit libraries. As the output
136        for "first char" and "need char" really means "non-UTF-char", I've changed
137        "byte" to "char", and slightly reworded the output. The documentation about
138        these values has also been (I hope) clarified.
140    10. Another JIT related optimization: use table jumps for selecting the correct
141        backtracking path, when more than four alternatives are present inside a
142        bracket.
144    11. Empty match is not possible, when the minimum length is greater than zero,
145        and there is no \K in the pattern. JIT should avoid empty match checks in
146        such cases.
148    12. In a caseless character class with UCP support, when a character with more
149        than one alternative case was not the first character of a range, not all
150        the alternative cases were added to the class. For example, s and \x{17f}
151        are both alternative cases for S: the class [RST] was handled correctly,
152        but [R-T] was not.
154    13. The configure.ac file always checked for pthread support when JIT was
155        enabled. This is not used in Windows, so I have put this test inside a
156        check for the presence of windows.h (which was already tested for).
158    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
159        The algorithm provides a way to skip certain starting offsets, and usually
160        faster than linear prefix searches.
162    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
163        as for 'fr_FR' and 'french'. For some reason, however, it then used the
164        Windows-specific input and output files, which have 'french' screwed in.
165        So this could never have worked. One of the problems with locales is that
166        they aren't always the same. I have now updated RunTest so that it checks
167        the output of the locale test (test 3) against three different output
168        files, and it allows the test to pass if any one of them matches. With luck
169        this should make the test pass on some versions of Solaris where it was
170        failing. Because of the uncertainty, the script did not used to stop if
171        test 3 failed; it now does. If further versions of a French locale ever
172        come to light, they can now easily be added.
174    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
175        there was a message during ./configure, but it did not stop. This now
176        provokes an error. The invalid example in README has been corrected.
177        If a value less than the minimum is given, the minimum value has always
178        been used, but now a warning is given.
180    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
181        was a bug in the test system, which is now fixed. Also, the list of various
182        configurations that are tested for each release did not have one with both
183        16/32 bits and --enable-bar-anycrlf. It now does.
185    18. pcretest was missing "-C bsr" for displaying the \R default setting.
187    19. Little endian PowerPC systems are supported now by the JIT compiler.
189    20. The fast forward newline mechanism could enter to an infinite loop on
190        certain invalid UTF-8 input. Although we don't support these cases
191        this issue can be fixed by a performance optimization.
193    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
194        not take account if existing stack usage. There is now a new global
195        variable called pcre_stack_guard that can be set to point to an external
196        function to check stack availability. It is called at the start of
197        processing every parenthesized group.
199    22. A typo in the code meant that in ungreedy mode the max/min qualifier
200        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
201        not match "ab".
203    23. When UTF was disabled, the JIT program reported some incorrect compile
204        errors. These messages are silenced now.
206    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
207        compiler.
209    25. Change all the temporary files used in RunGrepTest to be different to those
210        used by RunTest so that the tests can be run simultaneously, for example by
211        "make -j check".
214    Version 8.34 15-December-2013
215    -----------------------------
217    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
218        executable memory. Patch inspired by Carsten Klein.
220    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
221        this macro is never tested and has no effect, because the work to support
222        coverage involves only compiling and linking options and special targets in
223        the Makefile. The comment in config.h implied that defining the macro would
224        enable coverage support, which is totally false. There was also support for
225        setting this macro in the CMake files (my fault, I just copied it from
226        configure). SUPPORT_GCOV has now been removed.
228    3.  Make a small performance improvement in strlen16() and strlen32() in
229        pcretest.
231    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
232        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
233        these cases). There was also one in pcretest.c.
235    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
237    6.  In UTF mode, the code for checking whether a group could match an empty
238        string (which is used for indefinitely repeated groups to allow for
239        breaking an infinite loop) was broken when the group contained a repeated
240        negated single-character class with a character that occupied more than one
241        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
242        UTF-8 mode). The effect was undefined: the group might or might not be
243        deemed as matching an empty string, or the program might have crashed.
245    7.  The code for checking whether a group could match an empty string was not
246        recognizing that \h, \H, \v, \V, and \R must match a character.
248    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
249        an empty string. If it can, pcretest shows this in its information output.
251    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
252        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
253        matched by pcre_exec() without using JIT:
255        (a) If the rest of the pattern did not match after a maximal run of
256            grapheme clusters, the code for backing up to try with fewer of them
257            did not always back up over a full grapheme when characters that do not
258            have the modifier quality were involved, e.g. Hangul syllables.
260        (b) If the match point in a subject started with modifier character, and
261            there was no match, the code could incorrectly back up beyond the match
262            point, and potentially beyond the first character in the subject,
263            leading to a segfault or an incorrect match result.
265    10. A conditional group with an assertion condition could lead to PCRE
266        recording an incorrect first data item for a match if no other first data
267        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
268        first data item, and therefore matched "ca" after "c" instead of at the
269        start.
271    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
272        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
274    12. The source of pcregrep now includes z/OS-specific code so that it can be
275        compiled for z/OS as part of the special z/OS distribution.
277    13. Added the -T and -TM options to pcretest.
279    14. The code in pcre_compile.c for creating the table of named capturing groups
280        has been refactored. Instead of creating the table dynamically during the
281        actual compiling pass, the information is remembered during the pre-compile
282        pass (on the stack unless there are more than 20 named groups, in which
283        case malloc() is used) and the whole table is created before the actual
284        compile happens. This has simplified the code (it is now nearly 150 lines
285        shorter) and prepared the way for better handling of references to groups
286        with duplicate names.
288    15. A back reference to a named subpattern when there is more than one of the
289        same name now checks them in the order in which they appear in the pattern.
290        The first one that is set is used for the reference. Previously only the
291        first one was inspected. This change makes PCRE more compatible with Perl.
293    16. Unicode character properties were updated from Unicode 6.3.0.
295    17. The compile-time code for auto-possessification has been refactored, based
296        on a patch by Zoltan Herczeg. It now happens after instead of during
297        compilation. The code is cleaner, and more cases are handled. The option
298        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
299        options in pcretest are provided to set it. It can also be set by
300        (*NO_AUTO_POSSESS) at the start of a pattern.
302    18. The character VT has been added to the default ("C" locale) set of
303        characters that match \s and are generally treated as white space,
304        following this same change in Perl 5.18. There is now no difference between
305        "Perl space" and "POSIX space". Whether VT is treated as white space in
306        other locales depends on the locale.
308    19. The code for checking named groups as conditions, either for being set or
309        for being recursed, has been refactored (this is related to 14 and 15
310        above). Processing unduplicated named groups should now be as fast at
311        numerical groups, and processing duplicated groups should be faster than
312        before.
314    20. Two patches to the CMake build system, by Alexander Barkov:
316          (1) Replace the "source" command by "." in CMakeLists.txt because
317              "source" is a bash-ism.
319          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
320              without these the CMake build does not work on Solaris.
322    21. Perl has changed its handling of \8 and \9. If there is no previously
323        encountered capturing group of those numbers, they are treated as the
324        literal characters 8 and 9 instead of a binary zero followed by the
325        literals. PCRE now does the same.
327    22. Following Perl, added \o{} to specify codepoints in octal, making it
328        possible to specify values greater than 0777 and also making them
329        unambiguous.
331    23. Perl now gives an error for missing closing braces after \x{... instead of
332        treating the string as literal. PCRE now does the same.
334    24. RunTest used to grumble if an inappropriate test was selected explicitly,
335        but just skip it when running all tests. This make it awkward to run ranges
336        of tests when one of them was inappropriate. Now it just skips any
337        inappropriate tests, as it always did when running all tests.
339    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
340        character types such as \d or \w, too many callouts were inserted, and the
341        data that they returned was rubbish.
343    26. In UCP mode, \s was not matching two of the characters that Perl matches,
344        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
345        were matched by \h. The code has now been refactored so that the lists of
346        the horizontal and vertical whitespace characters used for \h and \v (which
347        are defined only in one place) are now also used for \s.
349    27. Add JIT support for the 64 bit TileGX architecture.
350        Patch by Jiong Wang (Tilera Corporation).
352    28. Possessive quantifiers for classes (both explicit and automatically
353        generated) now use special opcodes instead of wrapping in ONCE brackets.
355    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
356        (because it's meaningless), this was not happening when PCRE_CASELESS was
357        set. Not wrong, but inefficient.
359    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
360        properties for \w, \d, etc) is present in a test regex. Otherwise if the
361        test contains no characters greater than 255, Perl doesn't realise it
362        should be using Unicode semantics.
364    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
365        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
366        does in Unicode mode.
368    32. Added the "forbid" facility to pcretest so that putting tests into the
369        wrong test files can sometimes be quickly detected.
371    33. There is now a limit (default 250) on the depth of nesting of parentheses.
372        This limit is imposed to control the amount of system stack used at compile
373        time. It can be changed at build time by --with-parens-nest-limit=xxx or
374        the equivalent in CMake.
376    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
377        errors. Perl warns for these when in warning mode, but PCRE has no facility
378        for giving warnings.
380    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
381        However, this was not working for (?!) because it is optimized to (*FAIL),
382        for which PCRE does not allow quantifiers. The optimization is now disabled
383        when a quantifier follows (?!). I can't see any use for this, but it makes
384        things uniform.
386    36. Perl no longer allows group names to start with digits, so I have made this
387        change also in PCRE. It simplifies the code a bit.
389    37. In extended mode, Perl ignores spaces before a + that indicates a
390        possessive quantifier. PCRE allowed a space before the quantifier, but not
391        before the possessive +. It now does.
393    38. The use of \K (reset reported match start) within a repeated possessive
394        group such as (a\Kb)*+ was not working.
396    40. Document that the same character tables must be used at compile time and
397        run time, and that the facility to pass tables to pcre_exec() and
398        pcre_dfa_exec() is for use only with saved/restored patterns.
400    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
401        features for Builds with MSVC:
403        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
404           builds). The .rc files can be used to set FileDescription and many other
405           attributes.
407        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
408           This allows higher-level build scripts which want .pdb files to avoid
409           hard-coding the exact files needed."
411    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
412        mean "start of word" and "end of word", respectively, as a transition aid.
414    43. A minimizing repeat of a class containing codepoints greater than 255 in
415        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
416        compiled to use the heap for recursion.
418    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
419        is configured.
422    Version 8.33 28-May-2013
423    ------------------------
425  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
426      avoid compiler signed/unsigned warnings. Added (int) casts to unsigned      avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
427      variables that are added to signed variables, to ensure the result is      variables that are added to signed variables, to ensure the result is
# Line 36  Version 8.33 28-April-2013 Line 454  Version 8.33 28-April-2013
455  9.  Optimizing fast_forward_start_bits in JIT.  9.  Optimizing fast_forward_start_bits in JIT.
457  10. Adding experimental support for callouts in JIT, and fixing some  10. Adding support for callouts in JIT, and fixing some issues revealed
458      issues revealed during this work. Namely:      during this work. Namely:
460      (a) Unoptimized capturing brackets incorrectly reset on backtrack.      (a) Unoptimized capturing brackets incorrectly reset on backtrack.
# Line 125  Version 8.33 28-April-2013 Line 543  Version 8.33 28-April-2013
543      have been moved to test 1, because either Perl or PCRE has changed, and      have been moved to test 1, because either Perl or PCRE has changed, and
544      these tests are now compatible.      these tests are now compatible.
546  32. Control verbs are handled in the same way in JIT and interpreter.  32. Backtracking control verbs are now handled in the same way in JIT and
547        interpreter.
549  33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that  33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
550      contained a forward subroutine reference caused a compile error.      contained a forward subroutine reference caused a compile error.
# Line 147  Version 8.33 28-April-2013 Line 566  Version 8.33 28-April-2013
567  39. Try madvise first before posix_madvise.  39. Try madvise first before posix_madvise.
569    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
570        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
571        original change locked out all matches of empty strings. This has been
572        changed so that one match of an empty string per line is recognized.
573        Subsequent searches on the same line (for colouring or for --only-matching,
574        for example) do not recognize empty strings.
576    41. Applied a user patch to fix a number of spelling mistakes in comments.
578    42. Data lines longer than 65536 caused pcretest to crash.
580    43. Clarified the data type for length and startoffset arguments for pcre_exec
581        and pcre_dfa_exec in the function-specific man pages, where they were
582        explicitly stated to be in bytes, never having been updated. I also added
583        some clarification to the pcreapi man page.
585    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
586        a segmentation fault.
589  Version 8.32 30-November-2012  Version 8.32 30-November-2012
590  -----------------------------  -----------------------------
# Line 1655  Version 7.9 11-Apr-09 Line 2093  Version 7.9 11-Apr-09
2093  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
2094      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
2095      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2096      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2097        8.33.]
2099  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
2100      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 1898  Version 7.7 07-May-08 Line 2337  Version 7.7 07-May-08
2337      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2338      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2339      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2340      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2341      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2342      was subsequently set up correctly.)      was subsequently set up correctly.)

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