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

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