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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.
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.
47    12. pcreposix.c included pcre.h before including pcre_internal.h. This caused a
48        conflict in the definition of PCRE_EXP_DECL. I have removed the include of
49        pcre.h as pcre_internal.h includes pcre.h itself. (This may be a bit of
50        historical tidying that never got done.)
54    Version 8.02 19-Mar-2010
55    ------------------------
57    1.  The Unicode data tables have been updated to Unicode 5.2.0.
59    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
60        configured.
62    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
63        original author of that file, following a query about its status.
65    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
66        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
68    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
69        quantifier applied to a forward-referencing subroutine call, could compile
70        incorrect code or give the error "internal error: previously-checked
71        referenced subpattern not found".
73    6.  Both MS Visual Studio and Symbian OS have problems with initializing
74        variables to point to external functions. For these systems, therefore,
75        pcre_malloc etc. are now initialized to local functions that call the
76        relevant global functions.
78    7.  There were two entries missing in the vectors called coptable and poptable
79        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
80        I've fixed the data, and added a kludgy way of testing at compile time that
81        the lengths are correct (equal to the number of opcodes).
83    8.  Following on from 7, I added a similar kludge to check the length of the
84        eint vector in pcreposix.c.
86    9.  Error texts for pcre_compile() are held as one long string to avoid too
87        much relocation at load time. To find a text, the string is searched,
88        counting zeros. There was no check for running off the end of the string,
89        which could happen if a new error number was added without updating the
90        string.
92    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
94    11. \K was not working if it appeared in an atomic group or in a group that
95        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
96        \K is "not well defined" if used in an assertion. PCRE now accepts it if
97        the assertion is positive, but not if it is negative.
99    12. Change 11 fortuitously reduced the size of the stack frame used in the
100        "match()" function of pcre_exec.c by one pointer. Forthcoming
101        implementation of support for (*MARK) will need an extra pointer on the
102        stack; I have reserved it now, so that the stack frame size does not
103        decrease.
105    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
106        item in branch that calls a recursion is a subroutine call - as in the
107        second branch in the above example - was incorrectly given the compile-
108        time error "recursive call could loop indefinitely" because pcre_compile()
109        was not correctly checking the subroutine for matching a non-empty string.
111    14. The checks for overrunning compiling workspace could trigger after an
112        overrun had occurred. This is a "should never occur" error, but it can be
113        triggered by pathological patterns such as hundreds of nested parentheses.
114        The checks now trigger 100 bytes before the end of the workspace.
116    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
119    Version 8.01 19-Jan-2010
120    ------------------------
122    1.  If a pattern contained a conditional subpattern with only one branch (in
123        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
124        computed the wrong minimum data length (which is of course zero for such
125        subpatterns). This could cause incorrect "no match" results.
127    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
128        the pattern is reset in the first branch, pcre_compile() failed with
129        "internal error: code overflow at offset...". This happened only when
130        the reset was to the original external option setting. (An optimization
131        abstracts leading options settings into an external setting, which was the
132        cause of this.)
134    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
135        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
136        assertion pattern did not match (meaning that the assertion was true), it
137        was incorrectly treated as false if the SKIP had been reached during the
138        matching. This also applied to assertions used as conditions.
140    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
141        assertion subpattern, including such a pattern used as a condition,
142        unpredictable results occurred, instead of the error return
145    5.  The C++ GlobalReplace function was not working like Perl for the special
146        situation when an empty string is matched. It now does the fancy magic
147        stuff that is necessary.
149    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
150        removed. (These were left over from very, very early versions of PCRE.)
152    7.  Some cosmetic changes to the code to make life easier when compiling it
153        as part of something else:
155        (a) Change DEBUG to PCRE_DEBUG.
157        (b) In pcre_compile(), rename the member of the "branch_chain" structure
158            called "current" as "current_branch", to prevent a collision with the
159            Linux macro when compiled as a kernel module.
161        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
162            prevent a collision with the Linux macro when compiled as a kernel
163            module.
165    8.  In pcre_compile() there are some checks for integer overflows that used to
166        cast potentially large values to (double). This has been changed to that
167        when building, a check for int64_t is made, and if it is found, it is used
168        instead, thus avoiding the use of floating point arithmetic. (There is no
169        other use of FP in PCRE.) If int64_t is not found, the fallback is to
170        double.
172    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
173        2005 (difference between two addresses compared to an unsigned value).
175    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
176        custom one, because of the following reported problem in Windows:
178          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
179              under Win32.
180          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
181              therefore missing the function definition.
182          - The compiler thus generates a "C" signature for the test function.
183          - The linker fails to find the "C" function.
184          - PCRE fails to configure if asked to do so against libbz2.
186    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
187        messages were output:
189          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
190          rerunning libtoolize, to keep the correct libtool macros in-tree.
191          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
193        I have done both of these things.
195    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
196        most of the time, it *can* run out if it is given a pattern that contains a
197        runaway infinite recursion. I updated the discussion in the pcrestack man
198        page.
200    13. Now that we have gone to the x.xx style of version numbers, the minor
201        version may start with zero. Using 08 or 09 is a bad idea because users
202        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
203        interpreted as invalid octal numbers. I've updated the previous comment in
204        configure.ac, and also added a check that gives an error if 08 or 09 are
205        used.
207    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
208        causing partial matching to fail when the end of the subject matched \W
209        in a UTF-8 pattern where \W was quantified with a minimum of 3.
211    15. There were some discrepancies between the declarations in pcre_internal.h
212        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
213        their definitions. The declarations used "const uschar *" and the
214        definitions used USPTR. Even though USPTR is normally defined as "const
215        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
216        reported that: "This difference in casting confuses some C++ compilers, for
217        example, SunCC recognizes above declarations as different functions and
218        generates broken code for hbpcre." I have changed the declarations to use
219        USPTR.
221    16. GNU libtool is named differently on some systems. The autogen.sh script now
222        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
223        (FreeBSD).
225    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
226        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
227        comment: "Figure out how to create a longlong from a string: strtoll and
228        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
229        instance, but it only takes 2 args instead of 3!"
231    18. A subtle bug concerned with back references has been fixed by a change of
232        specification, with a corresponding code fix. A pattern such as
233        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
234        refers, was giving matches when it shouldn't. For example, xa=xaaa would
235        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
236        same bug. Such groups have to be quantified to be useful, or contained
237        inside another quantified group. (If there's no repetition, the reference
238        can never match.) The problem arises because, having left the group and
239        moved on to the rest of the pattern, a later failure that backtracks into
240        the group uses the captured value from the final iteration of the group
241        rather than the correct earlier one. I have fixed this in PCRE by forcing
242        any group that contains a reference to itself to be an atomic group; that
243        is, there cannot be any backtracking into it once it has completed. This is
244        similar to recursive and subroutine calls.
247    Version 8.00 19-Oct-09
248  ----------------------  ----------------------
250  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
251      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
252      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
253      error.      error.
255  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,
256      "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
257      in a Windows environment.      in a Windows environment.
259  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
260      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
261      --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
262      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
263      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
264      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
265      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
267  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
268      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
269      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
270      the old behaviour.      the old behaviour.
272  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
273      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
274      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
275      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
277    6.  No libpcreposix.pc file was created for pkg-config; there was just
278        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
280    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
281        when UCP support is not needed, by modifying the Python script that
282        generates it from Unicode data files. This should not matter if the module
283        is correctly used as a library, but I received one complaint about 50K of
284        unwanted data. My guess is that the person linked everything into his
285        program rather than using a library. Anyway, it does no harm.
287    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
288        was a minimum greater than 1 for a wide character in a possessive
289        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
290        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
291        character. Chaos in the form of incorrect output or a compiling loop could
292        result.
294    9.  The restrictions on what a pattern can contain when partial matching is
295        requested for pcre_exec() have been removed. All patterns can now be
296        partially matched by this function. In addition, if there are at least two
297        slots in the offset vector, the offset of the earliest inspected character
298        for the match and the offset of the end of the subject are set in them when
299        PCRE_ERROR_PARTIAL is returned.
301    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
302        synonymous with PCRE_PARTIAL, for backwards compatibility, and
303        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
304        and may be more useful for multi-segment matching.
306    11. Partial matching with pcre_exec() is now more intuitive. A partial match
307        used to be given if ever the end of the subject was reached; now it is
308        given only if matching could not proceed because another character was
309        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
310        string "Z", which now yields "no match" instead of "partial match". In the
311        case of pcre_dfa_exec(), "no match" is given if every matching path for the
312        final character ended with (*FAIL).
314    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
315        if the pattern had a "must contain" character that was already found in the
316        earlier partial match, unless partial matching was again requested. For
317        example, with the pattern /dog.(body)?/, the "must contain" character is
318        "g". If the first part-match was for the string "dog", restarting with
319        "sbody" failed. This bug has been fixed.
321    13. The string returned by pcre_dfa_exec() after a partial match has been
322        changed so that it starts at the first inspected character rather than the
323        first character of the match. This makes a difference only if the pattern
324        starts with a lookbehind assertion or \b or \B (\K is not supported by
325        pcre_dfa_exec()). It's an incompatible change, but it makes the two
326        matching functions compatible, and I think it's the right thing to do.
328    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
329        so that the demonstration program is easily available in environments where
330        PCRE has not been installed from source.
332    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
333        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
334        library.
336    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
337        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
338        is not the first non-POSIX option to be added. Clearly some people find
339        these options useful.
341    17. If a caller to the POSIX matching function regexec() passes a non-zero
342        value for nmatch with a NULL value for pmatch, the value of
343        nmatch is forced to zero.
345    18. RunGrepTest did not have a test for the availability of the -u option of
346        the diff command, as RunTest does. It now checks in the same way as
347        RunTest, and also checks for the -b option.
349    19. If an odd number of negated classes containing just a single character
350        interposed, within parentheses, between a forward reference to a named
351        subpattern and the definition of the subpattern, compilation crashed with
352        an internal error, complaining that it could not find the referenced
353        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
354        [The bug was that it was starting one character too far in when skipping
355        over the character class, thus treating the ] as data rather than
356        terminating the class. This meant it could skip too much.]
358    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
359        /g option in pcretest when the pattern contains \K, which makes it possible
360        to have an empty string match not at the start, even when the pattern is
361        anchored. Updated pcretest and pcredemo to use this option.
363    21. If the maximum number of capturing subpatterns in a recursion was greater
364        than the maximum at the outer level, the higher number was returned, but
365        with unset values at the outer level. The correct (outer level) value is
366        now given.
368    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
369        PCRE did not set those parentheses (unlike Perl). I have now found a way to
370        make it do so. The string so far is captured, making this feature
371        compatible with Perl.
373    23. The tests have been re-organized, adding tests 11 and 12, to make it
374        possible to check the Perl 5.10 features against Perl 5.10.
376    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
377        pattern matches a fixed length string. PCRE did not allow this; now it
378        does. Neither allows recursion.
380    25. I finally figured out how to implement a request to provide the minimum
381        length of subject string that was needed in order to match a given pattern.
382        (It was back references and recursion that I had previously got hung up
383        on.) This code has now been added to pcre_study(); it finds a lower bound
384        to the length of subject needed. It is not necessarily the greatest lower
385        bound, but using it to avoid searching strings that are too short does give
386        some useful speed-ups. The value is available to calling programs via
387        pcre_fullinfo().
389    26. While implementing 25, I discovered to my embarrassment that pcretest had
390        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
391        study optimizations had never been tested with that matching function.
392        Oops. What is worse, even when it was passed study data, there was a bug in
393        pcre_dfa_exec() that meant it never actually used it. Double oops. There
394        were also very few tests of studied patterns with pcre_dfa_exec().
396    27. If (?| is used to create subpatterns with duplicate numbers, they are now
397        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
398        on the other side of the coin, they are no longer allowed to have different
399        names, because these cannot be distinguished in PCRE, and this has caused
400        confusion. (This is a difference from Perl.)
402    28. When duplicate subpattern names are present (necessarily with different
403        numbers, as required by 27 above), and a test is made by name in a
404        conditional pattern, either for a subpattern having been matched, or for
405        recursion in such a pattern, all the associated numbered subpatterns are
406        tested, and the overall condition is true if the condition is true for any
407        one of them. This is the way Perl works, and is also more like the way
408        testing by number works.
411  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
412  ---------------------  ---------------------

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