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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.00 ??-???-??  Version 8.02 01-Mar-2010
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
15    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
16        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
18    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
19        quantifier applied to a forward-referencing subroutine call, could compile
20        incorrect code or give the error "internal error: previously-checked
21        referenced subpattern not found".
23    6.  Both MS Visual Studio and Symbian OS have problems with initializing
24        variables to point to external functions. For these systems, therefore,
25        pcre_malloc etc. are now initialized to local functions that call the
26        relevant global functions.
28    7.  There were two entries missing in the vectors called coptable and poptable
29        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
30        I've fixed the data, and added a kludgy way of testing at compile time that
31        the lengths are correct (equal to the number of opcodes).
33    8.  Following on from 7, I added a similar kludge to check the length of the
34        eint vector in pcreposix.c.
36    9.  Error texts for pcre_compile() are held as one long string to avoid too
37        much relocation at load time. To find a text, the string is searched,
38        counting zeros. There was no check for running off the end of the string,
39        which could happen if a new error number was added without updating the
40        string.
43    Version 8.01 19-Jan-2010
44    ------------------------
46    1.  If a pattern contained a conditional subpattern with only one branch (in
47        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
48        computed the wrong minimum data length (which is of course zero for such
49        subpatterns). This could cause incorrect "no match" results.
51    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
52        the pattern is reset in the first branch, pcre_compile() failed with
53        "internal error: code overflow at offset...". This happened only when
54        the reset was to the original external option setting. (An optimization
55        abstracts leading options settings into an external setting, which was the
56        cause of this.)
58    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
59        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
60        assertion pattern did not match (meaning that the assertion was true), it
61        was incorrectly treated as false if the SKIP had been reached during the
62        matching. This also applied to assertions used as conditions.
64    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
65        assertion subpattern, including such a pattern used as a condition,
66        unpredictable results occurred, instead of the error return
69    5.  The C++ GlobalReplace function was not working like Perl for the special
70        situation when an empty string is matched. It now does the fancy magic
71        stuff that is necessary.
73    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
74        removed. (These were left over from very, very early versions of PCRE.)
76    7.  Some cosmetic changes to the code to make life easier when compiling it
77        as part of something else:
79        (a) Change DEBUG to PCRE_DEBUG.
81        (b) In pcre_compile(), rename the member of the "branch_chain" structure
82            called "current" as "current_branch", to prevent a collision with the
83            Linux macro when compiled as a kernel module.
85        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
86            prevent a collision with the Linux macro when compiled as a kernel
87            module.
89    8.  In pcre_compile() there are some checks for integer overflows that used to
90        cast potentially large values to (double). This has been changed to that
91        when building, a check for int64_t is made, and if it is found, it is used
92        instead, thus avoiding the use of floating point arithmetic. (There is no
93        other use of FP in PCRE.) If int64_t is not found, the fallback is to
94        double.
96    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
97        2005 (difference between two addresses compared to an unsigned value).
99    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
100        custom one, because of the following reported problem in Windows:
102          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
103              under Win32.
104          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
105              therefore missing the function definition.
106          - The compiler thus generates a "C" signature for the test function.
107          - The linker fails to find the "C" function.
108          - PCRE fails to configure if asked to do so against libbz2.
110    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
111        messages were output:
113          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
114          rerunning libtoolize, to keep the correct libtool macros in-tree.
115          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
117        I have done both of these things.
119    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
120        most of the time, it *can* run out if it is given a pattern that contains a
121        runaway infinite recursion. I updated the discussion in the pcrestack man
122        page.
124    13. Now that we have gone to the x.xx style of version numbers, the minor
125        version may start with zero. Using 08 or 09 is a bad idea because users
126        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
127        interpreted as invalid octal numbers. I've updated the previous comment in
128        configure.ac, and also added a check that gives an error if 08 or 09 are
129        used.
131    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
132        causing partial matching to fail when the end of the subject matched \W
133        in a UTF-8 pattern where \W was quantified with a minimum of 3.
135    15. There were some discrepancies between the declarations in pcre_internal.h
136        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
137        their definitions. The declarations used "const uschar *" and the
138        definitions used USPTR. Even though USPTR is normally defined as "const
139        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
140        reported that: "This difference in casting confuses some C++ compilers, for
141        example, SunCC recognizes above declarations as different functions and
142        generates broken code for hbpcre." I have changed the declarations to use
143        USPTR.
145    16. GNU libtool is named differently on some systems. The autogen.sh script now
146        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
147        (FreeBSD).
149    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
150        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
151        comment: "Figure out how to create a longlong from a string: strtoll and
152        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
153        instance, but it only takes 2 args instead of 3!"
155    18. A subtle bug concerned with back references has been fixed by a change of
156        specification, with a corresponding code fix. A pattern such as
157        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
158        refers, was giving matches when it shouldn't. For example, xa=xaaa would
159        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
160        same bug. Such groups have to be quantified to be useful, or contained
161        inside another quantified group. (If there's no repetition, the reference
162        can never match.) The problem arises because, having left the group and
163        moved on to the rest of the pattern, a later failure that backtracks into
164        the group uses the captured value from the final iteration of the group
165        rather than the correct earlier one. I have fixed this in PCRE by forcing
166        any group that contains a reference to itself to be an atomic group; that
167        is, there cannot be any backtracking into it once it has completed. This is
168        similar to recursive and subroutine calls.
171    Version 8.00 19-Oct-09
172  ----------------------  ----------------------
174  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
175      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
176      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
177      error.      error.
179  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,
180      "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
181      in a Windows environment.      in a Windows environment.
183  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
184      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
185      --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
186      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
187      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
188      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
189      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
191  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
192      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
193      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
194      the old behaviour.      the old behaviour.
196  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
197      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
198      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
199      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
201    6.  No libpcreposix.pc file was created for pkg-config; there was just
202        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
204    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
205        when UCP support is not needed, by modifying the Python script that
206        generates it from Unicode data files. This should not matter if the module
207        is correctly used as a library, but I received one complaint about 50K of
208        unwanted data. My guess is that the person linked everything into his
209        program rather than using a library. Anyway, it does no harm.
211    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
212        was a minimum greater than 1 for a wide character in a possessive
213        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
214        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
215        character. Chaos in the form of incorrect output or a compiling loop could
216        result.
218    9.  The restrictions on what a pattern can contain when partial matching is
219        requested for pcre_exec() have been removed. All patterns can now be
220        partially matched by this function. In addition, if there are at least two
221        slots in the offset vector, the offset of the earliest inspected character
222        for the match and the offset of the end of the subject are set in them when
223        PCRE_ERROR_PARTIAL is returned.
225    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
226        synonymous with PCRE_PARTIAL, for backwards compatibility, and
227        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
228        and may be more useful for multi-segment matching.
230    11. Partial matching with pcre_exec() is now more intuitive. A partial match
231        used to be given if ever the end of the subject was reached; now it is
232        given only if matching could not proceed because another character was
233        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
234        string "Z", which now yields "no match" instead of "partial match". In the
235        case of pcre_dfa_exec(), "no match" is given if every matching path for the
236        final character ended with (*FAIL).
238    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
239        if the pattern had a "must contain" character that was already found in the
240        earlier partial match, unless partial matching was again requested. For
241        example, with the pattern /dog.(body)?/, the "must contain" character is
242        "g". If the first part-match was for the string "dog", restarting with
243        "sbody" failed. This bug has been fixed.
245    13. The string returned by pcre_dfa_exec() after a partial match has been
246        changed so that it starts at the first inspected character rather than the
247        first character of the match. This makes a difference only if the pattern
248        starts with a lookbehind assertion or \b or \B (\K is not supported by
249        pcre_dfa_exec()). It's an incompatible change, but it makes the two
250        matching functions compatible, and I think it's the right thing to do.
252    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
253        so that the demonstration program is easily available in environments where
254        PCRE has not been installed from source.
256    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
257        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
258        library.
260    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
261        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
262        is not the first non-POSIX option to be added. Clearly some people find
263        these options useful.
265    17. If a caller to the POSIX matching function regexec() passes a non-zero
266        value for nmatch with a NULL value for pmatch, the value of
267        nmatch is forced to zero.
269    18. RunGrepTest did not have a test for the availability of the -u option of
270        the diff command, as RunTest does. It now checks in the same way as
271        RunTest, and also checks for the -b option.
273    19. If an odd number of negated classes containing just a single character
274        interposed, within parentheses, between a forward reference to a named
275        subpattern and the definition of the subpattern, compilation crashed with
276        an internal error, complaining that it could not find the referenced
277        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
278        [The bug was that it was starting one character too far in when skipping
279        over the character class, thus treating the ] as data rather than
280        terminating the class. This meant it could skip too much.]
282    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
283        /g option in pcretest when the pattern contains \K, which makes it possible
284        to have an empty string match not at the start, even when the pattern is
285        anchored. Updated pcretest and pcredemo to use this option.
287    21. If the maximum number of capturing subpatterns in a recursion was greater
288        than the maximum at the outer level, the higher number was returned, but
289        with unset values at the outer level. The correct (outer level) value is
290        now given.
292    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
293        PCRE did not set those parentheses (unlike Perl). I have now found a way to
294        make it do so. The string so far is captured, making this feature
295        compatible with Perl.
297    23. The tests have been re-organized, adding tests 11 and 12, to make it
298        possible to check the Perl 5.10 features against Perl 5.10.
300    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
301        pattern matches a fixed length string. PCRE did not allow this; now it
302        does. Neither allows recursion.
304    25. I finally figured out how to implement a request to provide the minimum
305        length of subject string that was needed in order to match a given pattern.
306        (It was back references and recursion that I had previously got hung up
307        on.) This code has now been added to pcre_study(); it finds a lower bound
308        to the length of subject needed. It is not necessarily the greatest lower
309        bound, but using it to avoid searching strings that are too short does give
310        some useful speed-ups. The value is available to calling programs via
311        pcre_fullinfo().
313    26. While implementing 25, I discovered to my embarrassment that pcretest had
314        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
315        study optimizations had never been tested with that matching function.
316        Oops. What is worse, even when it was passed study data, there was a bug in
317        pcre_dfa_exec() that meant it never actually used it. Double oops. There
318        were also very few tests of studied patterns with pcre_dfa_exec().
320    27. If (?| is used to create subpatterns with duplicate numbers, they are now
321        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
322        on the other side of the coin, they are no longer allowed to have different
323        names, because these cannot be distinguished in PCRE, and this has caused
324        confusion. (This is a difference from Perl.)
326    28. When duplicate subpattern names are present (necessarily with different
327        numbers, as required by 27 above), and a test is made by name in a
328        conditional pattern, either for a subpattern having been matched, or for
329        recursion in such a pattern, all the associated numbered subpatterns are
330        tested, and the overall condition is true if the condition is true for any
331        one of them. This is the way Perl works, and is also more like the way
332        testing by number works.
335  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
336  ---------------------  ---------------------

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