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

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