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revision 478 by ph10, Sun Jan 3 16:05:13 2010 UTC revision 574 by ph10, Sat Nov 20 17:47:27 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.01 11-Dec-09  Version 8.11 10-Oct-2010
5  ----------------------  ------------------------
7    1.  (*THEN) was not working properly if there were untried alternatives prior
8        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
9        backtracked to try for "b" instead of moving to the next alternative branch
10        at the same level (in this case, to look for "c"). The Perl documentation
11        is clear that when (*THEN) is backtracked onto, it goes to the "next
12        alternative in the innermost enclosing group".
14    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
15        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
16        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
17        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
18        (*THEN).
20    3.  If \s appeared in a character class, it removed the VT character from
21        the class, even if it had been included by some previous item, for example
22        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
23        of \s, but is part of the POSIX "space" class.)
25    4.  A partial match never returns an empty string (because you can always
26        match an empty string at the end of the subject); however the checking for
27        an empty string was starting at the "start of match" point. This has been
28        changed to the "earliest inspected character" point, because the returned
29        data for a partial match starts at this character. This means that, for
30        example, /(?<=abc)def/ gives a partial match for the subject "abc"
31        (previously it gave "no match").
33    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
34        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
35        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
36        has an implication that the given string is incomplete (because a partial
37        match is preferred over a full match). For this reason, these items now
38        give a partial match in this situation. [Aside: previously, the one case
39        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
40        match rather than a full match, which was wrong by the old rules, but is
41        now correct.]
43    6.  There was a bug in the handling of #-introduced comments, recognized when
44        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
45        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
46        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
47        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
48        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
49        places in pcre_compile().
51    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
52        comments when looking ahead for named forward references to subpatterns,
53        the only newline sequence it recognized was NL. It now handles newlines
54        according to the set newline convention.
56    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
57        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
58        cater for a lack of strerror(). These oversights have been fixed.
60    9.  Added --match-limit and --recursion-limit to pcregrep.
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
64    11. When the -o option was used, pcregrep was setting a return code of 1, even
65        when matches were found, and --line-buffered was not being honoured.
67    12. Added an optional parentheses number to the -o and --only-matching options
68        of pcregrep.
70    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
71        can match an empty string. The code to do it in pcretest and pcredemo
72        needed fixing:
74        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
75            only one byte after an empty string match just before CRLF (this case
76            just got forgotten; "any" and "anycrlf" were OK).
78        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
79            mode when an empty string match preceded an ASCII character followed by
80            a non-ASCII character. (The code for advancing by one character rather
81            than one byte was nonsense.)
83        (c) The pcredemo.c sample program did not have any code at all to handle
84            the cases when CRLF is a valid newline sequence.
86    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
87        as a starting offset was within the subject string. There is now a new
88        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
89        negative or greater than the length of the string. In order to test this,
90        pcretest is extended to allow the setting of negative starting offsets.
92    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
93        starting offset points to the beginning of a UTF-8 character was
94        unnecessarily clumsy. I tidied it up.
96    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
97        bad UTF-8 sequence and one that is incomplete.
99    17. Nobody had reported that the --include_dir option, which was added in
100        release 7.7 should have been called --include-dir (hyphen, not underscore)
101        for compatibility with GNU grep. I have changed it to --include-dir, but
102        left --include_dir as an undocumented synonym, and the same for
103        --exclude-dir, though that is not available in GNU grep, at least as of
104        release 2.5.4.
106    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
107        characters from a string of bytes) have been redefined so as not to use
108        loops, in order to improve performance in some environments. At the same
109        time, I abstracted some of the common code into auxiliary macros to save
110        repetition (this should not affect the compiled code).
112    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
113        compile-time error is now given if \c is not followed by an ASCII
114        character, that is, a byte less than 128. (In EBCDIC mode, the code is
115        different, and any byte value is allowed.)
118    Version 8.10 25-Jun-2010
119    ------------------------
121    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
122        THEN.
124    2.  (*ACCEPT) was not working when inside an atomic group.
126    3.  Inside a character class, \B is treated as a literal by default, but
127        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
128        causes the error). The code is unchanged, but I tidied the documentation.
130    4.  Inside a character class, PCRE always treated \R and \X as literals,
131        whereas Perl faults them if its -w option is set. I have changed PCRE so
132        that it faults them when PCRE_EXTRA is set.
134    5.  Added support for \N, which always matches any character other than
135        newline. (It is the same as "." when PCRE_DOTALL is not set.)
137    6.  When compiling pcregrep with newer versions of gcc which may have
138        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
139        declared with attribute warn_unused_result" were given. Just casting the
140        result to (void) does not stop the warnings; a more elaborate fudge is
141        needed. I've used a macro to implement this.
143    7.  Minor change to pcretest.c to avoid a compiler warning.
145    8.  Added four artifical Unicode properties to help with an option to make
146        \s etc use properties (see next item). The new properties are: Xan
147        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
149    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
150        use Unicode properties. (*UCP) at the start of a pattern can be used to set
151        this option. Modified pcretest to add /W to test this facility. Added
152        REG_UCP to make it available via the POSIX interface.
154    10. Added --line-buffered to pcregrep.
156    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
157        studied, and the match started with a letter with a code point greater than
158        127 whose first byte was different to the first byte of the other case of
159        the letter, the other case of this starting letter was not recognized
160        (#976).
162    12. If a pattern that was studied started with a repeated Unicode property
163        test, for example, \p{Nd}+, there was the theoretical possibility of
164        setting up an incorrect bitmap of starting bytes, but fortunately it could
165        not have actually happened in practice until change 8 above was made (it
166        added property types that matched character-matching opcodes).
168    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
169        possible starting bytes for non-anchored patterns.
171    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
172        \R, and also a number of cases that involve Unicode properties, both
173        explicit and implicit when PCRE_UCP is set.
175    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
176        input, it could crash or give wrong results if characters with values
177        greater than 0xc0 were present in the subject string. (Detail: it assumed
178        UTF-8 input when processing these items.)
180    16. Added a lot of (int) casts to avoid compiler warnings in systems where
181        size_t is 64-bit (#991).
183    17. Added a check for running out of memory when PCRE is compiled with
184        --disable-stack-for-recursion (#990).
186    18. If the last data line in a file for pcretest does not have a newline on
187        the end, a newline was missing in the output.
189    19. The default pcre_chartables.c file recognizes only ASCII characters (values
190        less than 128) in its various bitmaps. However, there is a facility for
191        generating tables according to the current locale when PCRE is compiled. It
192        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
193        characters, are recognized by isspace() and therefore were getting set in
194        these tables, and indeed these tables seem to approximate to ISO 8859. This
195        caused a problem in UTF-8 mode when pcre_study() was used to create a list
196        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
197        which of course cannot start UTF-8 characters. I have changed the code so
198        that only real ASCII characters (less than 128) and the correct starting
199        bytes for UTF-8 encodings are set for characters greater than 127 when in
200        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
201        altogether.)
203    20. Added the /T option to pcretest so as to be able to run tests with non-
204        standard character tables, thus making it possible to include the tests
205        used for 19 above in the standard set of tests.
207    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
208        reference to a subpattern the other side of a comment that contains an
209        opening parenthesis caused either an internal compiling error, or a
210        reference to the wrong subpattern.
213    Version 8.02 19-Mar-2010
214    ------------------------
216    1.  The Unicode data tables have been updated to Unicode 5.2.0.
218    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
219        configured.
221    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
222        original author of that file, following a query about its status.
224    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
225        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
227    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
228        quantifier applied to a forward-referencing subroutine call, could compile
229        incorrect code or give the error "internal error: previously-checked
230        referenced subpattern not found".
232    6.  Both MS Visual Studio and Symbian OS have problems with initializing
233        variables to point to external functions. For these systems, therefore,
234        pcre_malloc etc. are now initialized to local functions that call the
235        relevant global functions.
237    7.  There were two entries missing in the vectors called coptable and poptable
238        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
239        I've fixed the data, and added a kludgy way of testing at compile time that
240        the lengths are correct (equal to the number of opcodes).
242    8.  Following on from 7, I added a similar kludge to check the length of the
243        eint vector in pcreposix.c.
245    9.  Error texts for pcre_compile() are held as one long string to avoid too
246        much relocation at load time. To find a text, the string is searched,
247        counting zeros. There was no check for running off the end of the string,
248        which could happen if a new error number was added without updating the
249        string.
251    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
253    11. \K was not working if it appeared in an atomic group or in a group that
254        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
255        \K is "not well defined" if used in an assertion. PCRE now accepts it if
256        the assertion is positive, but not if it is negative.
258    12. Change 11 fortuitously reduced the size of the stack frame used in the
259        "match()" function of pcre_exec.c by one pointer. Forthcoming
260        implementation of support for (*MARK) will need an extra pointer on the
261        stack; I have reserved it now, so that the stack frame size does not
262        decrease.
264    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
265        item in branch that calls a recursion is a subroutine call - as in the
266        second branch in the above example - was incorrectly given the compile-
267        time error "recursive call could loop indefinitely" because pcre_compile()
268        was not correctly checking the subroutine for matching a non-empty string.
270    14. The checks for overrunning compiling workspace could trigger after an
271        overrun had occurred. This is a "should never occur" error, but it can be
272        triggered by pathological patterns such as hundreds of nested parentheses.
273        The checks now trigger 100 bytes before the end of the workspace.
275    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
278    Version 8.01 19-Jan-2010
279    ------------------------
281  1.  If a pattern contained a conditional subpattern with only one branch (in  1.  If a pattern contained a conditional subpattern with only one branch (in
282      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
283      computed the wrong minimum data length (which is of course zero for such      computed the wrong minimum data length (which is of course zero for such
284      subpatterns).      subpatterns). This could cause incorrect "no match" results.
286  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
287      the pattern is reset in the first branch, pcre_compile() failed with      the pattern is reset in the first branch, pcre_compile() failed with
# Line 61  Version 8.01 11-Dec-09 Line 335  Version 8.01 11-Dec-09
335      custom one, because of the following reported problem in Windows:      custom one, because of the following reported problem in Windows:
337        - libbz2 uses the Pascal calling convention (WINAPI) for the functions        - libbz2 uses the Pascal calling convention (WINAPI) for the functions
338          under Win32.            under Win32.
339        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
340          therefore missing the function definition.            therefore missing the function definition.
341        - The compiler thus generates a "C" signature for the test function.        - The compiler thus generates a "C" signature for the test function.
342        - The linker fails to find the "C" function.        - The linker fails to find the "C" function.
343        - PCRE fails to configure if asked to do so against libbz2.        - PCRE fails to configure if asked to do so against libbz2.
345    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
346        messages were output:
348          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
349          rerunning libtoolize, to keep the correct libtool macros in-tree.
350          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
352        I have done both of these things.
354    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
355        most of the time, it *can* run out if it is given a pattern that contains a
356        runaway infinite recursion. I updated the discussion in the pcrestack man
357        page.
359    13. Now that we have gone to the x.xx style of version numbers, the minor
360        version may start with zero. Using 08 or 09 is a bad idea because users
361        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
362        interpreted as invalid octal numbers. I've updated the previous comment in
363        configure.ac, and also added a check that gives an error if 08 or 09 are
364        used.
366    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
367        causing partial matching to fail when the end of the subject matched \W
368        in a UTF-8 pattern where \W was quantified with a minimum of 3.
370    15. There were some discrepancies between the declarations in pcre_internal.h
371        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
372        their definitions. The declarations used "const uschar *" and the
373        definitions used USPTR. Even though USPTR is normally defined as "const
374        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
375        reported that: "This difference in casting confuses some C++ compilers, for
376        example, SunCC recognizes above declarations as different functions and
377        generates broken code for hbpcre." I have changed the declarations to use
378        USPTR.
380    16. GNU libtool is named differently on some systems. The autogen.sh script now
381        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
382        (FreeBSD).
384    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
385        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
386        comment: "Figure out how to create a longlong from a string: strtoll and
387        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
388        instance, but it only takes 2 args instead of 3!"
390    18. A subtle bug concerned with back references has been fixed by a change of
391        specification, with a corresponding code fix. A pattern such as
392        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
393        refers, was giving matches when it shouldn't. For example, xa=xaaa would
394        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
395        same bug. Such groups have to be quantified to be useful, or contained
396        inside another quantified group. (If there's no repetition, the reference
397        can never match.) The problem arises because, having left the group and
398        moved on to the rest of the pattern, a later failure that backtracks into
399        the group uses the captured value from the final iteration of the group
400        rather than the correct earlier one. I have fixed this in PCRE by forcing
401        any group that contains a reference to itself to be an atomic group; that
402        is, there cannot be any backtracking into it once it has completed. This is
403        similar to recursive and subroutine calls.
406  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
407  ----------------------  ----------------------

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