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revision 480 by ph10, Sun Jan 3 17:29:59 2010 UTC revision 587 by ph10, Fri Jan 14 19:01:25 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.01 11-Dec-09  Version 8.12 12-Jan-2011
5  ----------------------  ------------------------
6    
7    1.  Fixed some typos in the markup of the man pages, and wrote a script that
8        checks for such things as part of the documentation building process.
9    
10    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
11        --match-limit and --recursion-limit options (added for 8.11). In
12        particular, this made one of the standard tests crash. (The integer value
13        went into the wrong half of a long int.)
14    
15    3.  If the --colour option was given to pcregrep with -v (invert match), it
16        did strange things, either producing crazy output, or crashing. It should,
17        of course, ignore a request for colour when reporting lines that do not
18        match.
19    
20    4.  Another pcregrep bug caused similar problems if --colour was specified with
21        -M (multiline) and the pattern match finished with a line ending.
22    
23    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
24        matched in multiline mode, the following line was shown as part of the
25        match. This seems wrong, so I have changed it.
26    
27    6.  If pcregrep was compiled under Windows, there was a reference to the
28        function pcregrep_exit() before it was defined. I am assuming this was
29        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
30        reported by a user. I've moved the definition above the reference.
31    
32    
33    Version 8.11 10-Dec-2010
34    ------------------------
35    
36    1.  (*THEN) was not working properly if there were untried alternatives prior
37        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
38        backtracked to try for "b" instead of moving to the next alternative branch
39        at the same level (in this case, to look for "c"). The Perl documentation
40        is clear that when (*THEN) is backtracked onto, it goes to the "next
41        alternative in the innermost enclosing group".
42    
43    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
44        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
45        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
46        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
47        (*THEN).
48    
49    3.  If \s appeared in a character class, it removed the VT character from
50        the class, even if it had been included by some previous item, for example
51        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
52        of \s, but is part of the POSIX "space" class.)
53    
54    4.  A partial match never returns an empty string (because you can always
55        match an empty string at the end of the subject); however the checking for
56        an empty string was starting at the "start of match" point. This has been
57        changed to the "earliest inspected character" point, because the returned
58        data for a partial match starts at this character. This means that, for
59        example, /(?<=abc)def/ gives a partial match for the subject "abc"
60        (previously it gave "no match").
61    
62    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
63        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
64        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
65        has an implication that the given string is incomplete (because a partial
66        match is preferred over a full match). For this reason, these items now
67        give a partial match in this situation. [Aside: previously, the one case
68        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
69        match rather than a full match, which was wrong by the old rules, but is
70        now correct.]
71    
72    6.  There was a bug in the handling of #-introduced comments, recognized when
73        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
74        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
75        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
76        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
77        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
78        places in pcre_compile().
79    
80    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
81        comments when looking ahead for named forward references to subpatterns,
82        the only newline sequence it recognized was NL. It now handles newlines
83        according to the set newline convention.
84    
85    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
86        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
87        cater for a lack of strerror(). These oversights have been fixed.
88    
89    9.  Added --match-limit and --recursion-limit to pcregrep.
90    
91    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
92    
93    11. When the -o option was used, pcregrep was setting a return code of 1, even
94        when matches were found, and --line-buffered was not being honoured.
95    
96    12. Added an optional parentheses number to the -o and --only-matching options
97        of pcregrep.
98    
99    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
100        can match an empty string. The code to do it in pcretest and pcredemo
101        needed fixing:
102    
103        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
104            only one byte after an empty string match just before CRLF (this case
105            just got forgotten; "any" and "anycrlf" were OK).
106    
107        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
108            mode when an empty string match preceded an ASCII character followed by
109            a non-ASCII character. (The code for advancing by one character rather
110            than one byte was nonsense.)
111    
112        (c) The pcredemo.c sample program did not have any code at all to handle
113            the cases when CRLF is a valid newline sequence.
114    
115    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
116        as a starting offset was within the subject string. There is now a new
117        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
118        negative or greater than the length of the string. In order to test this,
119        pcretest is extended to allow the setting of negative starting offsets.
120    
121    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
122        starting offset points to the beginning of a UTF-8 character was
123        unnecessarily clumsy. I tidied it up.
124    
125    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
126        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
127    
128    17. Nobody had reported that the --include_dir option, which was added in
129        release 7.7 should have been called --include-dir (hyphen, not underscore)
130        for compatibility with GNU grep. I have changed it to --include-dir, but
131        left --include_dir as an undocumented synonym, and the same for
132        --exclude-dir, though that is not available in GNU grep, at least as of
133        release 2.5.4.
134    
135    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
136        characters from a string of bytes) have been redefined so as not to use
137        loops, in order to improve performance in some environments. At the same
138        time, I abstracted some of the common code into auxiliary macros to save
139        repetition (this should not affect the compiled code).
140    
141    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
142        compile-time error is now given if \c is not followed by an ASCII
143        character, that is, a byte less than 128. (In EBCDIC mode, the code is
144        different, and any byte value is allowed.)
145    
146    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
147        START_OPTIMIZE option, which is now allowed at compile time - but just
148        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
149        to pcregrep and other applications that have no direct access to PCRE
150        options. The new /Y option in pcretest sets this option when calling
151        pcre_compile().
152    
153    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
154        back references. Groups containing recursive back references were forced to
155        be atomic by that change, but in the case of named groups, the amount of
156        memory required was incorrectly computed, leading to "Failed: internal
157        error: code overflow". This has been fixed.
158    
159    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
160        pcretest.c, to avoid build problems in some Borland environments.
161    
162    
163    Version 8.10 25-Jun-2010
164    ------------------------
165    
166    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
167        THEN.
168    
169    2.  (*ACCEPT) was not working when inside an atomic group.
170    
171    3.  Inside a character class, \B is treated as a literal by default, but
172        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
173        causes the error). The code is unchanged, but I tidied the documentation.
174    
175    4.  Inside a character class, PCRE always treated \R and \X as literals,
176        whereas Perl faults them if its -w option is set. I have changed PCRE so
177        that it faults them when PCRE_EXTRA is set.
178    
179    5.  Added support for \N, which always matches any character other than
180        newline. (It is the same as "." when PCRE_DOTALL is not set.)
181    
182    6.  When compiling pcregrep with newer versions of gcc which may have
183        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
184        declared with attribute warn_unused_result" were given. Just casting the
185        result to (void) does not stop the warnings; a more elaborate fudge is
186        needed. I've used a macro to implement this.
187    
188    7.  Minor change to pcretest.c to avoid a compiler warning.
189    
190    8.  Added four artifical Unicode properties to help with an option to make
191        \s etc use properties (see next item). The new properties are: Xan
192        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
193    
194    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
195        use Unicode properties. (*UCP) at the start of a pattern can be used to set
196        this option. Modified pcretest to add /W to test this facility. Added
197        REG_UCP to make it available via the POSIX interface.
198    
199    10. Added --line-buffered to pcregrep.
200    
201    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
202        studied, and the match started with a letter with a code point greater than
203        127 whose first byte was different to the first byte of the other case of
204        the letter, the other case of this starting letter was not recognized
205        (#976).
206    
207    12. If a pattern that was studied started with a repeated Unicode property
208        test, for example, \p{Nd}+, there was the theoretical possibility of
209        setting up an incorrect bitmap of starting bytes, but fortunately it could
210        not have actually happened in practice until change 8 above was made (it
211        added property types that matched character-matching opcodes).
212    
213    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
214        possible starting bytes for non-anchored patterns.
215    
216    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
217        \R, and also a number of cases that involve Unicode properties, both
218        explicit and implicit when PCRE_UCP is set.
219    
220    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
221        input, it could crash or give wrong results if characters with values
222        greater than 0xc0 were present in the subject string. (Detail: it assumed
223        UTF-8 input when processing these items.)
224    
225    16. Added a lot of (int) casts to avoid compiler warnings in systems where
226        size_t is 64-bit (#991).
227    
228    17. Added a check for running out of memory when PCRE is compiled with
229        --disable-stack-for-recursion (#990).
230    
231    18. If the last data line in a file for pcretest does not have a newline on
232        the end, a newline was missing in the output.
233    
234    19. The default pcre_chartables.c file recognizes only ASCII characters (values
235        less than 128) in its various bitmaps. However, there is a facility for
236        generating tables according to the current locale when PCRE is compiled. It
237        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
238        characters, are recognized by isspace() and therefore were getting set in
239        these tables, and indeed these tables seem to approximate to ISO 8859. This
240        caused a problem in UTF-8 mode when pcre_study() was used to create a list
241        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
242        which of course cannot start UTF-8 characters. I have changed the code so
243        that only real ASCII characters (less than 128) and the correct starting
244        bytes for UTF-8 encodings are set for characters greater than 127 when in
245        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
246        altogether.)
247    
248    20. Added the /T option to pcretest so as to be able to run tests with non-
249        standard character tables, thus making it possible to include the tests
250        used for 19 above in the standard set of tests.
251    
252    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
253        reference to a subpattern the other side of a comment that contains an
254        opening parenthesis caused either an internal compiling error, or a
255        reference to the wrong subpattern.
256    
257    
258    Version 8.02 19-Mar-2010
259    ------------------------
260    
261    1.  The Unicode data tables have been updated to Unicode 5.2.0.
262    
263    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
264        configured.
265    
266    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
267        original author of that file, following a query about its status.
268    
269    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
270        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
271    
272    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
273        quantifier applied to a forward-referencing subroutine call, could compile
274        incorrect code or give the error "internal error: previously-checked
275        referenced subpattern not found".
276    
277    6.  Both MS Visual Studio and Symbian OS have problems with initializing
278        variables to point to external functions. For these systems, therefore,
279        pcre_malloc etc. are now initialized to local functions that call the
280        relevant global functions.
281    
282    7.  There were two entries missing in the vectors called coptable and poptable
283        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
284        I've fixed the data, and added a kludgy way of testing at compile time that
285        the lengths are correct (equal to the number of opcodes).
286    
287    8.  Following on from 7, I added a similar kludge to check the length of the
288        eint vector in pcreposix.c.
289    
290    9.  Error texts for pcre_compile() are held as one long string to avoid too
291        much relocation at load time. To find a text, the string is searched,
292        counting zeros. There was no check for running off the end of the string,
293        which could happen if a new error number was added without updating the
294        string.
295    
296    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
297    
298    11. \K was not working if it appeared in an atomic group or in a group that
299        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
300        \K is "not well defined" if used in an assertion. PCRE now accepts it if
301        the assertion is positive, but not if it is negative.
302    
303    12. Change 11 fortuitously reduced the size of the stack frame used in the
304        "match()" function of pcre_exec.c by one pointer. Forthcoming
305        implementation of support for (*MARK) will need an extra pointer on the
306        stack; I have reserved it now, so that the stack frame size does not
307        decrease.
308    
309    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
310        item in branch that calls a recursion is a subroutine call - as in the
311        second branch in the above example - was incorrectly given the compile-
312        time error "recursive call could loop indefinitely" because pcre_compile()
313        was not correctly checking the subroutine for matching a non-empty string.
314    
315    14. The checks for overrunning compiling workspace could trigger after an
316        overrun had occurred. This is a "should never occur" error, but it can be
317        triggered by pathological patterns such as hundreds of nested parentheses.
318        The checks now trigger 100 bytes before the end of the workspace.
319    
320    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
321    
322    
323    Version 8.01 19-Jan-2010
324    ------------------------
325    
326  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
327      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
328      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
329      subpatterns).      subpatterns). This could cause incorrect "no match" results.
330    
331  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
332      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 380  Version 8.01 11-Dec-09
380      custom one, because of the following reported problem in Windows:      custom one, because of the following reported problem in Windows:
381    
382        - libbz2 uses the Pascal calling convention (WINAPI) for the functions        - libbz2 uses the Pascal calling convention (WINAPI) for the functions
383          under Win32.            under Win32.
384        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
385          therefore missing the function definition.            therefore missing the function definition.
386        - The compiler thus generates a "C" signature for the test function.        - The compiler thus generates a "C" signature for the test function.
387        - The linker fails to find the "C" function.        - The linker fails to find the "C" function.
388        - PCRE fails to configure if asked to do so against libbz2.        - PCRE fails to configure if asked to do so against libbz2.
389    
390  11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these  11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
391      messages were output:      messages were output:
392    
393        Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and        Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
394        rerunning libtoolize, to keep the correct libtool macros in-tree.        rerunning libtoolize, to keep the correct libtool macros in-tree.
395        Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.        Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
396    
397      I have done both of these things.      I have done both of these things.
398    
399  12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()  12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
400      most of the time, it *can* run out if it is given a pattern that contains a      most of the time, it *can* run out if it is given a pattern that contains a
401      runaway infinite recursion. I updated the discussion in the pcrestack man      runaway infinite recursion. I updated the discussion in the pcrestack man
402      page.      page.
403    
404    13. Now that we have gone to the x.xx style of version numbers, the minor
405        version may start with zero. Using 08 or 09 is a bad idea because users
406        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
407        interpreted as invalid octal numbers. I've updated the previous comment in
408        configure.ac, and also added a check that gives an error if 08 or 09 are
409        used.
410    
411    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
412        causing partial matching to fail when the end of the subject matched \W
413        in a UTF-8 pattern where \W was quantified with a minimum of 3.
414    
415    15. There were some discrepancies between the declarations in pcre_internal.h
416        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
417        their definitions. The declarations used "const uschar *" and the
418        definitions used USPTR. Even though USPTR is normally defined as "const
419        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
420        reported that: "This difference in casting confuses some C++ compilers, for
421        example, SunCC recognizes above declarations as different functions and
422        generates broken code for hbpcre." I have changed the declarations to use
423        USPTR.
424    
425    16. GNU libtool is named differently on some systems. The autogen.sh script now
426        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
427        (FreeBSD).
428    
429    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
430        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
431        comment: "Figure out how to create a longlong from a string: strtoll and
432        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
433        instance, but it only takes 2 args instead of 3!"
434    
435    18. A subtle bug concerned with back references has been fixed by a change of
436        specification, with a corresponding code fix. A pattern such as
437        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
438        refers, was giving matches when it shouldn't. For example, xa=xaaa would
439        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
440        same bug. Such groups have to be quantified to be useful, or contained
441        inside another quantified group. (If there's no repetition, the reference
442        can never match.) The problem arises because, having left the group and
443        moved on to the rest of the pattern, a later failure that backtracks into
444        the group uses the captured value from the final iteration of the group
445        rather than the correct earlier one. I have fixed this in PCRE by forcing
446        any group that contains a reference to itself to be an atomic group; that
447        is, there cannot be any backtracking into it once it has completed. This is
448        similar to recursive and subroutine calls.
449    
450    
451  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09

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