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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.00 ??-???-??  Version 8.03 26-Mar-2010
5    ------------------------
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
11    Version 8.02 19-Mar-2010
12    ------------------------
14    1.  The Unicode data tables have been updated to Unicode 5.2.0.
16    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
17        configured.
19    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
20        original author of that file, following a query about its status.
22    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
23        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
25    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
26        quantifier applied to a forward-referencing subroutine call, could compile
27        incorrect code or give the error "internal error: previously-checked
28        referenced subpattern not found".
30    6.  Both MS Visual Studio and Symbian OS have problems with initializing
31        variables to point to external functions. For these systems, therefore,
32        pcre_malloc etc. are now initialized to local functions that call the
33        relevant global functions.
35    7.  There were two entries missing in the vectors called coptable and poptable
36        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
37        I've fixed the data, and added a kludgy way of testing at compile time that
38        the lengths are correct (equal to the number of opcodes).
40    8.  Following on from 7, I added a similar kludge to check the length of the
41        eint vector in pcreposix.c.
43    9.  Error texts for pcre_compile() are held as one long string to avoid too
44        much relocation at load time. To find a text, the string is searched,
45        counting zeros. There was no check for running off the end of the string,
46        which could happen if a new error number was added without updating the
47        string.
49    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
51    11. \K was not working if it appeared in an atomic group or in a group that
52        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
53        \K is "not well defined" if used in an assertion. PCRE now accepts it if
54        the assertion is positive, but not if it is negative.
56    12. Change 11 fortuitously reduced the size of the stack frame used in the
57        "match()" function of pcre_exec.c by one pointer. Forthcoming
58        implementation of support for (*MARK) will need an extra pointer on the
59        stack; I have reserved it now, so that the stack frame size does not
60        decrease.
62    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
63        item in branch that calls a recursion is a subroutine call - as in the
64        second branch in the above example - was incorrectly given the compile-
65        time error "recursive call could loop indefinitely" because pcre_compile()
66        was not correctly checking the subroutine for matching a non-empty string.
68    14. The checks for overrunning compiling workspace could trigger after an
69        overrun had occurred. This is a "should never occur" error, but it can be
70        triggered by pathological patterns such as hundreds of nested parentheses.
71        The checks now trigger 100 bytes before the end of the workspace.
73    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
76    Version 8.01 19-Jan-2010
77    ------------------------
79    1.  If a pattern contained a conditional subpattern with only one branch (in
80        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
81        computed the wrong minimum data length (which is of course zero for such
82        subpatterns). This could cause incorrect "no match" results.
84    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
85        the pattern is reset in the first branch, pcre_compile() failed with
86        "internal error: code overflow at offset...". This happened only when
87        the reset was to the original external option setting. (An optimization
88        abstracts leading options settings into an external setting, which was the
89        cause of this.)
91    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
92        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
93        assertion pattern did not match (meaning that the assertion was true), it
94        was incorrectly treated as false if the SKIP had been reached during the
95        matching. This also applied to assertions used as conditions.
97    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
98        assertion subpattern, including such a pattern used as a condition,
99        unpredictable results occurred, instead of the error return
102    5.  The C++ GlobalReplace function was not working like Perl for the special
103        situation when an empty string is matched. It now does the fancy magic
104        stuff that is necessary.
106    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
107        removed. (These were left over from very, very early versions of PCRE.)
109    7.  Some cosmetic changes to the code to make life easier when compiling it
110        as part of something else:
112        (a) Change DEBUG to PCRE_DEBUG.
114        (b) In pcre_compile(), rename the member of the "branch_chain" structure
115            called "current" as "current_branch", to prevent a collision with the
116            Linux macro when compiled as a kernel module.
118        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
119            prevent a collision with the Linux macro when compiled as a kernel
120            module.
122    8.  In pcre_compile() there are some checks for integer overflows that used to
123        cast potentially large values to (double). This has been changed to that
124        when building, a check for int64_t is made, and if it is found, it is used
125        instead, thus avoiding the use of floating point arithmetic. (There is no
126        other use of FP in PCRE.) If int64_t is not found, the fallback is to
127        double.
129    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
130        2005 (difference between two addresses compared to an unsigned value).
132    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
133        custom one, because of the following reported problem in Windows:
135          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
136              under Win32.
137          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
138              therefore missing the function definition.
139          - The compiler thus generates a "C" signature for the test function.
140          - The linker fails to find the "C" function.
141          - PCRE fails to configure if asked to do so against libbz2.
143    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
144        messages were output:
146          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
147          rerunning libtoolize, to keep the correct libtool macros in-tree.
148          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
150        I have done both of these things.
152    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
153        most of the time, it *can* run out if it is given a pattern that contains a
154        runaway infinite recursion. I updated the discussion in the pcrestack man
155        page.
157    13. Now that we have gone to the x.xx style of version numbers, the minor
158        version may start with zero. Using 08 or 09 is a bad idea because users
159        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
160        interpreted as invalid octal numbers. I've updated the previous comment in
161        configure.ac, and also added a check that gives an error if 08 or 09 are
162        used.
164    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
165        causing partial matching to fail when the end of the subject matched \W
166        in a UTF-8 pattern where \W was quantified with a minimum of 3.
168    15. There were some discrepancies between the declarations in pcre_internal.h
169        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
170        their definitions. The declarations used "const uschar *" and the
171        definitions used USPTR. Even though USPTR is normally defined as "const
172        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
173        reported that: "This difference in casting confuses some C++ compilers, for
174        example, SunCC recognizes above declarations as different functions and
175        generates broken code for hbpcre." I have changed the declarations to use
176        USPTR.
178    16. GNU libtool is named differently on some systems. The autogen.sh script now
179        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
180        (FreeBSD).
182    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
183        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
184        comment: "Figure out how to create a longlong from a string: strtoll and
185        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
186        instance, but it only takes 2 args instead of 3!"
188    18. A subtle bug concerned with back references has been fixed by a change of
189        specification, with a corresponding code fix. A pattern such as
190        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
191        refers, was giving matches when it shouldn't. For example, xa=xaaa would
192        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
193        same bug. Such groups have to be quantified to be useful, or contained
194        inside another quantified group. (If there's no repetition, the reference
195        can never match.) The problem arises because, having left the group and
196        moved on to the rest of the pattern, a later failure that backtracks into
197        the group uses the captured value from the final iteration of the group
198        rather than the correct earlier one. I have fixed this in PCRE by forcing
199        any group that contains a reference to itself to be an atomic group; that
200        is, there cannot be any backtracking into it once it has completed. This is
201        similar to recursive and subroutine calls.
204    Version 8.00 19-Oct-09
205  ----------------------  ----------------------
207  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
208      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
209      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
210      error.      error.
212    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
213        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
214        in a Windows environment.
216    3.  The pcregrep --count option prints the count for each file even when it is
217        zero, as does GNU grep. However, pcregrep was also printing all files when
218        --files-with-matches was added. Now, when both options are given, it prints
219        counts only for those files that have at least one match. (GNU grep just
220        prints the file name in this circumstance, but including the count seems
221        more useful - otherwise, why use --count?) Also ensured that the
222        combination -clh just lists non-zero counts, with no names.
224    4.  The long form of the pcregrep -F option was incorrectly implemented as
225        --fixed_strings instead of --fixed-strings. This is an incompatible change,
226        but it seems right to fix it, and I didn't think it was worth preserving
227        the old behaviour.
229    5.  The command line items --regex=pattern and --regexp=pattern were not
230        recognized by pcregrep, which required --regex pattern or --regexp pattern
231        (with a space rather than an '='). The man page documented the '=' forms,
232        which are compatible with GNU grep; these now work.
234    6.  No libpcreposix.pc file was created for pkg-config; there was just
235        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
237    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
238        when UCP support is not needed, by modifying the Python script that
239        generates it from Unicode data files. This should not matter if the module
240        is correctly used as a library, but I received one complaint about 50K of
241        unwanted data. My guess is that the person linked everything into his
242        program rather than using a library. Anyway, it does no harm.
244    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
245        was a minimum greater than 1 for a wide character in a possessive
246        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
247        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
248        character. Chaos in the form of incorrect output or a compiling loop could
249        result.
251    9.  The restrictions on what a pattern can contain when partial matching is
252        requested for pcre_exec() have been removed. All patterns can now be
253        partially matched by this function. In addition, if there are at least two
254        slots in the offset vector, the offset of the earliest inspected character
255        for the match and the offset of the end of the subject are set in them when
256        PCRE_ERROR_PARTIAL is returned.
258    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
259        synonymous with PCRE_PARTIAL, for backwards compatibility, and
260        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
261        and may be more useful for multi-segment matching.
263    11. Partial matching with pcre_exec() is now more intuitive. A partial match
264        used to be given if ever the end of the subject was reached; now it is
265        given only if matching could not proceed because another character was
266        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
267        string "Z", which now yields "no match" instead of "partial match". In the
268        case of pcre_dfa_exec(), "no match" is given if every matching path for the
269        final character ended with (*FAIL).
271    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
272        if the pattern had a "must contain" character that was already found in the
273        earlier partial match, unless partial matching was again requested. For
274        example, with the pattern /dog.(body)?/, the "must contain" character is
275        "g". If the first part-match was for the string "dog", restarting with
276        "sbody" failed. This bug has been fixed.
278    13. The string returned by pcre_dfa_exec() after a partial match has been
279        changed so that it starts at the first inspected character rather than the
280        first character of the match. This makes a difference only if the pattern
281        starts with a lookbehind assertion or \b or \B (\K is not supported by
282        pcre_dfa_exec()). It's an incompatible change, but it makes the two
283        matching functions compatible, and I think it's the right thing to do.
285    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
286        so that the demonstration program is easily available in environments where
287        PCRE has not been installed from source.
289    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
290        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
291        library.
293    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
294        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
295        is not the first non-POSIX option to be added. Clearly some people find
296        these options useful.
298    17. If a caller to the POSIX matching function regexec() passes a non-zero
299        value for nmatch with a NULL value for pmatch, the value of
300        nmatch is forced to zero.
302    18. RunGrepTest did not have a test for the availability of the -u option of
303        the diff command, as RunTest does. It now checks in the same way as
304        RunTest, and also checks for the -b option.
306    19. If an odd number of negated classes containing just a single character
307        interposed, within parentheses, between a forward reference to a named
308        subpattern and the definition of the subpattern, compilation crashed with
309        an internal error, complaining that it could not find the referenced
310        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
311        [The bug was that it was starting one character too far in when skipping
312        over the character class, thus treating the ] as data rather than
313        terminating the class. This meant it could skip too much.]
315    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
316        /g option in pcretest when the pattern contains \K, which makes it possible
317        to have an empty string match not at the start, even when the pattern is
318        anchored. Updated pcretest and pcredemo to use this option.
320    21. If the maximum number of capturing subpatterns in a recursion was greater
321        than the maximum at the outer level, the higher number was returned, but
322        with unset values at the outer level. The correct (outer level) value is
323        now given.
325    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
326        PCRE did not set those parentheses (unlike Perl). I have now found a way to
327        make it do so. The string so far is captured, making this feature
328        compatible with Perl.
330    23. The tests have been re-organized, adding tests 11 and 12, to make it
331        possible to check the Perl 5.10 features against Perl 5.10.
333    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
334        pattern matches a fixed length string. PCRE did not allow this; now it
335        does. Neither allows recursion.
337    25. I finally figured out how to implement a request to provide the minimum
338        length of subject string that was needed in order to match a given pattern.
339        (It was back references and recursion that I had previously got hung up
340        on.) This code has now been added to pcre_study(); it finds a lower bound
341        to the length of subject needed. It is not necessarily the greatest lower
342        bound, but using it to avoid searching strings that are too short does give
343        some useful speed-ups. The value is available to calling programs via
344        pcre_fullinfo().
346    26. While implementing 25, I discovered to my embarrassment that pcretest had
347        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
348        study optimizations had never been tested with that matching function.
349        Oops. What is worse, even when it was passed study data, there was a bug in
350        pcre_dfa_exec() that meant it never actually used it. Double oops. There
351        were also very few tests of studied patterns with pcre_dfa_exec().
353    27. If (?| is used to create subpatterns with duplicate numbers, they are now
354        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
355        on the other side of the coin, they are no longer allowed to have different
356        names, because these cannot be distinguished in PCRE, and this has caused
357        confusion. (This is a difference from Perl.)
359    28. When duplicate subpattern names are present (necessarily with different
360        numbers, as required by 27 above), and a test is made by name in a
361        conditional pattern, either for a subpattern having been matched, or for
362        recursion in such a pattern, all the associated numbered subpatterns are
363        tested, and the overall condition is true if the condition is true for any
364        one of them. This is the way Perl works, and is also more like the way
365        testing by number works.
368  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
369  ---------------------  ---------------------

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