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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.10 03-Jun-2010
5    ------------------------
6    
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
9    
10    2.  (*ACCEPT) was not working when inside an atomic group.
11    
12    3.  Inside a character class, \B is treated as a literal by default, but
13        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14        causes the error). The code is unchanged, but I tidied the documentation.
15    
16    4.  Inside a character class, PCRE always treated \R and \X as literals,
17        whereas Perl faults them if its -w option is set. I have changed PCRE so
18        that it faults them when PCRE_EXTRA is set.
19    
20    5.  Added support for \N, which always matches any character other than
21        newline. (It is the same as "." when PCRE_DOTALL is not set.)
22    
23    6.  When compiling pcregrep with newer versions of gcc which may have
24        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25        declared with attribute warn_unused_result" were given. Just casting the
26        result to (void) does not stop the warnings; a more elaborate fudge is
27        needed. I've used a macro to implement this.
28    
29    7.  Minor change to pcretest.c to avoid a compiler warning.
30    
31    8.  Added four artifical Unicode properties to help with an option to make
32        \s etc use properties (see next item). The new properties are: Xan
33        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
34    
35    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
36        use Unicode properties. (*UCP) at the start of a pattern can be used to set
37        this option. Modified pcretest to add /W to test this facility. Added
38        REG_UCP to make it available via the POSIX interface.
39    
40    10. Added --line-buffered to pcregrep.
41    
42    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
43        studied, and the match started with a letter with a code point greater than
44        127 whose first byte was different to the first byte of the other case of
45        the letter, the other case of this starting letter was not recognized
46        (#976).
47    
48    12. If a pattern that was studied started with a repeated Unicode property
49        test, for example, \p{Nd}+, there was the theoretical possibility of
50        setting up an incorrect bitmap of starting bytes, but fortunately it could
51        not have actually happened in practice until change 8 above was made (it
52        added property types that matched character-matching opcodes).
53    
54    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
55        possible starting bytes for non-anchored patterns.
56    
57    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
58        \R, and also a number of cases that involve Unicode properties, both
59        explicit and implicit when PCRE_UCP is set.
60    
61    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
62        input, it could crash or give wrong results if characters with values
63        greater than 0xc0 were present in the subject string. (Detail: it assumed
64        UTF-8 input when processing these items.)
65    
66    16. Added a lot of (int) casts to avoid compiler warnings in systems where
67        size_t is 64-bit (#991).
68    
69    17. Added a check for running out of memory when PCRE is compiled with
70        --disable-stack-for-recursion (#990).
71    
72    18. If the last data line in a file for pcretest does not have a newline on
73        the end, a newline was missing in the output.
74    
75    19. The default pcre_chartables.c file recognizes only ASCII characters (values
76        less than 128) in its various bitmaps. However, there is a facility for
77        generating tables according to the current locale when PCRE is compiled. It
78        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
79        characters, are recognized by isspace() and therefore were getting set in
80        these tables, and indeed these tables seem to approximate to ISO 8859. This
81        caused a problem in UTF-8 mode when pcre_study() was used to create a list
82        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
83        which of course cannot start UTF-8 characters. I have changed the code so
84        that only real ASCII characters (less than 128) and the correct starting
85        bytes for UTF-8 encodings are set for characters greater than 127 when in
86        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
87        altogether.)
88    
89    20. Added the /T option to pcretest so as to be able to run tests with non-
90        standard character tables, thus making it possible to include the tests
91        used for 19 above in the standard set of tests.
92    
93    
94    Version 8.02 19-Mar-2010
95    ------------------------
96    
97    1.  The Unicode data tables have been updated to Unicode 5.2.0.
98    
99    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
100        configured.
101    
102    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
103        original author of that file, following a query about its status.
104    
105    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
106        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
107    
108    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
109        quantifier applied to a forward-referencing subroutine call, could compile
110        incorrect code or give the error "internal error: previously-checked
111        referenced subpattern not found".
112    
113    6.  Both MS Visual Studio and Symbian OS have problems with initializing
114        variables to point to external functions. For these systems, therefore,
115        pcre_malloc etc. are now initialized to local functions that call the
116        relevant global functions.
117    
118    7.  There were two entries missing in the vectors called coptable and poptable
119        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
120        I've fixed the data, and added a kludgy way of testing at compile time that
121        the lengths are correct (equal to the number of opcodes).
122    
123    8.  Following on from 7, I added a similar kludge to check the length of the
124        eint vector in pcreposix.c.
125    
126    9.  Error texts for pcre_compile() are held as one long string to avoid too
127        much relocation at load time. To find a text, the string is searched,
128        counting zeros. There was no check for running off the end of the string,
129        which could happen if a new error number was added without updating the
130        string.
131    
132    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
133    
134    11. \K was not working if it appeared in an atomic group or in a group that
135        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
136        \K is "not well defined" if used in an assertion. PCRE now accepts it if
137        the assertion is positive, but not if it is negative.
138    
139    12. Change 11 fortuitously reduced the size of the stack frame used in the
140        "match()" function of pcre_exec.c by one pointer. Forthcoming
141        implementation of support for (*MARK) will need an extra pointer on the
142        stack; I have reserved it now, so that the stack frame size does not
143        decrease.
144    
145    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
146        item in branch that calls a recursion is a subroutine call - as in the
147        second branch in the above example - was incorrectly given the compile-
148        time error "recursive call could loop indefinitely" because pcre_compile()
149        was not correctly checking the subroutine for matching a non-empty string.
150    
151    14. The checks for overrunning compiling workspace could trigger after an
152        overrun had occurred. This is a "should never occur" error, but it can be
153        triggered by pathological patterns such as hundreds of nested parentheses.
154        The checks now trigger 100 bytes before the end of the workspace.
155    
156    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
157    
158    
159    Version 8.01 19-Jan-2010
160    ------------------------
161    
162    1.  If a pattern contained a conditional subpattern with only one branch (in
163        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
164        computed the wrong minimum data length (which is of course zero for such
165        subpatterns). This could cause incorrect "no match" results.
166    
167    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
168        the pattern is reset in the first branch, pcre_compile() failed with
169        "internal error: code overflow at offset...". This happened only when
170        the reset was to the original external option setting. (An optimization
171        abstracts leading options settings into an external setting, which was the
172        cause of this.)
173    
174    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
175        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
176        assertion pattern did not match (meaning that the assertion was true), it
177        was incorrectly treated as false if the SKIP had been reached during the
178        matching. This also applied to assertions used as conditions.
179    
180    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
181        assertion subpattern, including such a pattern used as a condition,
182        unpredictable results occurred, instead of the error return
183        PCRE_ERROR_DFA_UITEM.
184    
185    5.  The C++ GlobalReplace function was not working like Perl for the special
186        situation when an empty string is matched. It now does the fancy magic
187        stuff that is necessary.
188    
189    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
190        removed. (These were left over from very, very early versions of PCRE.)
191    
192    7.  Some cosmetic changes to the code to make life easier when compiling it
193        as part of something else:
194    
195        (a) Change DEBUG to PCRE_DEBUG.
196    
197        (b) In pcre_compile(), rename the member of the "branch_chain" structure
198            called "current" as "current_branch", to prevent a collision with the
199            Linux macro when compiled as a kernel module.
200    
201        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
202            prevent a collision with the Linux macro when compiled as a kernel
203            module.
204    
205    8.  In pcre_compile() there are some checks for integer overflows that used to
206        cast potentially large values to (double). This has been changed to that
207        when building, a check for int64_t is made, and if it is found, it is used
208        instead, thus avoiding the use of floating point arithmetic. (There is no
209        other use of FP in PCRE.) If int64_t is not found, the fallback is to
210        double.
211    
212    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
213        2005 (difference between two addresses compared to an unsigned value).
214    
215    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
216        custom one, because of the following reported problem in Windows:
217    
218          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
219              under Win32.
220          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
221              therefore missing the function definition.
222          - The compiler thus generates a "C" signature for the test function.
223          - The linker fails to find the "C" function.
224          - PCRE fails to configure if asked to do so against libbz2.
225    
226    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
227        messages were output:
228    
229          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
230          rerunning libtoolize, to keep the correct libtool macros in-tree.
231          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
232    
233        I have done both of these things.
234    
235    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
236        most of the time, it *can* run out if it is given a pattern that contains a
237        runaway infinite recursion. I updated the discussion in the pcrestack man
238        page.
239    
240    13. Now that we have gone to the x.xx style of version numbers, the minor
241        version may start with zero. Using 08 or 09 is a bad idea because users
242        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
243        interpreted as invalid octal numbers. I've updated the previous comment in
244        configure.ac, and also added a check that gives an error if 08 or 09 are
245        used.
246    
247    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
248        causing partial matching to fail when the end of the subject matched \W
249        in a UTF-8 pattern where \W was quantified with a minimum of 3.
250    
251    15. There were some discrepancies between the declarations in pcre_internal.h
252        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
253        their definitions. The declarations used "const uschar *" and the
254        definitions used USPTR. Even though USPTR is normally defined as "const
255        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
256        reported that: "This difference in casting confuses some C++ compilers, for
257        example, SunCC recognizes above declarations as different functions and
258        generates broken code for hbpcre." I have changed the declarations to use
259        USPTR.
260    
261    16. GNU libtool is named differently on some systems. The autogen.sh script now
262        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
263        (FreeBSD).
264    
265    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
266        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
267        comment: "Figure out how to create a longlong from a string: strtoll and
268        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
269        instance, but it only takes 2 args instead of 3!"
270    
271    18. A subtle bug concerned with back references has been fixed by a change of
272        specification, with a corresponding code fix. A pattern such as
273        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
274        refers, was giving matches when it shouldn't. For example, xa=xaaa would
275        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
276        same bug. Such groups have to be quantified to be useful, or contained
277        inside another quantified group. (If there's no repetition, the reference
278        can never match.) The problem arises because, having left the group and
279        moved on to the rest of the pattern, a later failure that backtracks into
280        the group uses the captured value from the final iteration of the group
281        rather than the correct earlier one. I have fixed this in PCRE by forcing
282        any group that contains a reference to itself to be an atomic group; that
283        is, there cannot be any backtracking into it once it has completed. This is
284        similar to recursive and subroutine calls.
285    
286    
287    Version 8.00 19-Oct-09
288    ----------------------
289    
290    1.  The table for translating pcre_compile() error codes into POSIX error codes
291        was out-of-date, and there was no check on the pcre_compile() error code
292        being within the table. This could lead to an OK return being given in
293        error.
294    
295    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
296        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
297        in a Windows environment.
298    
299    3.  The pcregrep --count option prints the count for each file even when it is
300        zero, as does GNU grep. However, pcregrep was also printing all files when
301        --files-with-matches was added. Now, when both options are given, it prints
302        counts only for those files that have at least one match. (GNU grep just
303        prints the file name in this circumstance, but including the count seems
304        more useful - otherwise, why use --count?) Also ensured that the
305        combination -clh just lists non-zero counts, with no names.
306    
307    4.  The long form of the pcregrep -F option was incorrectly implemented as
308        --fixed_strings instead of --fixed-strings. This is an incompatible change,
309        but it seems right to fix it, and I didn't think it was worth preserving
310        the old behaviour.
311    
312    5.  The command line items --regex=pattern and --regexp=pattern were not
313        recognized by pcregrep, which required --regex pattern or --regexp pattern
314        (with a space rather than an '='). The man page documented the '=' forms,
315        which are compatible with GNU grep; these now work.
316    
317    6.  No libpcreposix.pc file was created for pkg-config; there was just
318        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
319    
320    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
321        when UCP support is not needed, by modifying the Python script that
322        generates it from Unicode data files. This should not matter if the module
323        is correctly used as a library, but I received one complaint about 50K of
324        unwanted data. My guess is that the person linked everything into his
325        program rather than using a library. Anyway, it does no harm.
326    
327    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
328        was a minimum greater than 1 for a wide character in a possessive
329        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
330        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
331        character. Chaos in the form of incorrect output or a compiling loop could
332        result.
333    
334    9.  The restrictions on what a pattern can contain when partial matching is
335        requested for pcre_exec() have been removed. All patterns can now be
336        partially matched by this function. In addition, if there are at least two
337        slots in the offset vector, the offset of the earliest inspected character
338        for the match and the offset of the end of the subject are set in them when
339        PCRE_ERROR_PARTIAL is returned.
340    
341    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
342        synonymous with PCRE_PARTIAL, for backwards compatibility, and
343        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
344        and may be more useful for multi-segment matching.
345    
346    11. Partial matching with pcre_exec() is now more intuitive. A partial match
347        used to be given if ever the end of the subject was reached; now it is
348        given only if matching could not proceed because another character was
349        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
350        string "Z", which now yields "no match" instead of "partial match". In the
351        case of pcre_dfa_exec(), "no match" is given if every matching path for the
352        final character ended with (*FAIL).
353    
354    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
355        if the pattern had a "must contain" character that was already found in the
356        earlier partial match, unless partial matching was again requested. For
357        example, with the pattern /dog.(body)?/, the "must contain" character is
358        "g". If the first part-match was for the string "dog", restarting with
359        "sbody" failed. This bug has been fixed.
360    
361    13. The string returned by pcre_dfa_exec() after a partial match has been
362        changed so that it starts at the first inspected character rather than the
363        first character of the match. This makes a difference only if the pattern
364        starts with a lookbehind assertion or \b or \B (\K is not supported by
365        pcre_dfa_exec()). It's an incompatible change, but it makes the two
366        matching functions compatible, and I think it's the right thing to do.
367    
368    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
369        so that the demonstration program is easily available in environments where
370        PCRE has not been installed from source.
371    
372    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
373        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
374        library.
375    
376    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
377        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
378        is not the first non-POSIX option to be added. Clearly some people find
379        these options useful.
380    
381    17. If a caller to the POSIX matching function regexec() passes a non-zero
382        value for nmatch with a NULL value for pmatch, the value of
383        nmatch is forced to zero.
384    
385    18. RunGrepTest did not have a test for the availability of the -u option of
386        the diff command, as RunTest does. It now checks in the same way as
387        RunTest, and also checks for the -b option.
388    
389    19. If an odd number of negated classes containing just a single character
390        interposed, within parentheses, between a forward reference to a named
391        subpattern and the definition of the subpattern, compilation crashed with
392        an internal error, complaining that it could not find the referenced
393        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
394        [The bug was that it was starting one character too far in when skipping
395        over the character class, thus treating the ] as data rather than
396        terminating the class. This meant it could skip too much.]
397    
398    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
399        /g option in pcretest when the pattern contains \K, which makes it possible
400        to have an empty string match not at the start, even when the pattern is
401        anchored. Updated pcretest and pcredemo to use this option.
402    
403    21. If the maximum number of capturing subpatterns in a recursion was greater
404        than the maximum at the outer level, the higher number was returned, but
405        with unset values at the outer level. The correct (outer level) value is
406        now given.
407    
408    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
409        PCRE did not set those parentheses (unlike Perl). I have now found a way to
410        make it do so. The string so far is captured, making this feature
411        compatible with Perl.
412    
413    23. The tests have been re-organized, adding tests 11 and 12, to make it
414        possible to check the Perl 5.10 features against Perl 5.10.
415    
416    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
417        pattern matches a fixed length string. PCRE did not allow this; now it
418        does. Neither allows recursion.
419    
420    25. I finally figured out how to implement a request to provide the minimum
421        length of subject string that was needed in order to match a given pattern.
422        (It was back references and recursion that I had previously got hung up
423        on.) This code has now been added to pcre_study(); it finds a lower bound
424        to the length of subject needed. It is not necessarily the greatest lower
425        bound, but using it to avoid searching strings that are too short does give
426        some useful speed-ups. The value is available to calling programs via
427        pcre_fullinfo().
428    
429    26. While implementing 25, I discovered to my embarrassment that pcretest had
430        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
431        study optimizations had never been tested with that matching function.
432        Oops. What is worse, even when it was passed study data, there was a bug in
433        pcre_dfa_exec() that meant it never actually used it. Double oops. There
434        were also very few tests of studied patterns with pcre_dfa_exec().
435    
436    27. If (?| is used to create subpatterns with duplicate numbers, they are now
437        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
438        on the other side of the coin, they are no longer allowed to have different
439        names, because these cannot be distinguished in PCRE, and this has caused
440        confusion. (This is a difference from Perl.)
441    
442    28. When duplicate subpattern names are present (necessarily with different
443        numbers, as required by 27 above), and a test is made by name in a
444        conditional pattern, either for a subpattern having been matched, or for
445        recursion in such a pattern, all the associated numbered subpatterns are
446        tested, and the overall condition is true if the condition is true for any
447        one of them. This is the way Perl works, and is also more like the way
448        testing by number works.
449    
450    
451  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
452  ---------------------  ---------------------
453    
# Line 112  Version 7.9 11-Apr-09 Line 559  Version 7.9 11-Apr-09
559    
560  26. Changed a few more instances of "const unsigned char *" to USPTR, making  26. Changed a few more instances of "const unsigned char *" to USPTR, making
561      the feature of a custom pointer more persuasive (as requested by a user).      the feature of a custom pointer more persuasive (as requested by a user).
562    
563  27. Wrapped the definitions of fileno and isatty for Windows, which appear in  27. Wrapped the definitions of fileno and isatty for Windows, which appear in
564      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
565      pre-defined.      pre-defined.
566    
567  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
568    
569    29. Arrange for flags added by the "release type" setting in CMake to be shown
570        in the configuration summary.
571    
572    
573  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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