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

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