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revision 478 by ph10, Sun Jan 3 16:05:13 2010 UTC revision 566 by ph10, Wed Nov 3 18:32:55 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.01 11-Dec-09  Version 8.11 10-Oct-2010
5  ----------------------  ------------------------
6    
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".
13    
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).
19    
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.)
24    
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").
32    
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.]
42    
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().
50    
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.
55    
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.
59    
60    9.  Added --match-limit and --recursion-limit to pcregrep.
61    
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
63    
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.
66    
67    12. Added an optional parentheses number to the -o and --only-matching options
68        of pcregrep.
69    
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:
73    
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).
77    
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.)
82    
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.
85    
86    
87    Version 8.10 25-Jun-2010
88    ------------------------
89    
90    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
91        THEN.
92    
93    2.  (*ACCEPT) was not working when inside an atomic group.
94    
95    3.  Inside a character class, \B is treated as a literal by default, but
96        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
97        causes the error). The code is unchanged, but I tidied the documentation.
98    
99    4.  Inside a character class, PCRE always treated \R and \X as literals,
100        whereas Perl faults them if its -w option is set. I have changed PCRE so
101        that it faults them when PCRE_EXTRA is set.
102    
103    5.  Added support for \N, which always matches any character other than
104        newline. (It is the same as "." when PCRE_DOTALL is not set.)
105    
106    6.  When compiling pcregrep with newer versions of gcc which may have
107        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
108        declared with attribute warn_unused_result" were given. Just casting the
109        result to (void) does not stop the warnings; a more elaborate fudge is
110        needed. I've used a macro to implement this.
111    
112    7.  Minor change to pcretest.c to avoid a compiler warning.
113    
114    8.  Added four artifical Unicode properties to help with an option to make
115        \s etc use properties (see next item). The new properties are: Xan
116        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
117    
118    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
119        use Unicode properties. (*UCP) at the start of a pattern can be used to set
120        this option. Modified pcretest to add /W to test this facility. Added
121        REG_UCP to make it available via the POSIX interface.
122    
123    10. Added --line-buffered to pcregrep.
124    
125    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
126        studied, and the match started with a letter with a code point greater than
127        127 whose first byte was different to the first byte of the other case of
128        the letter, the other case of this starting letter was not recognized
129        (#976).
130    
131    12. If a pattern that was studied started with a repeated Unicode property
132        test, for example, \p{Nd}+, there was the theoretical possibility of
133        setting up an incorrect bitmap of starting bytes, but fortunately it could
134        not have actually happened in practice until change 8 above was made (it
135        added property types that matched character-matching opcodes).
136    
137    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
138        possible starting bytes for non-anchored patterns.
139    
140    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
141        \R, and also a number of cases that involve Unicode properties, both
142        explicit and implicit when PCRE_UCP is set.
143    
144    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
145        input, it could crash or give wrong results if characters with values
146        greater than 0xc0 were present in the subject string. (Detail: it assumed
147        UTF-8 input when processing these items.)
148    
149    16. Added a lot of (int) casts to avoid compiler warnings in systems where
150        size_t is 64-bit (#991).
151    
152    17. Added a check for running out of memory when PCRE is compiled with
153        --disable-stack-for-recursion (#990).
154    
155    18. If the last data line in a file for pcretest does not have a newline on
156        the end, a newline was missing in the output.
157    
158    19. The default pcre_chartables.c file recognizes only ASCII characters (values
159        less than 128) in its various bitmaps. However, there is a facility for
160        generating tables according to the current locale when PCRE is compiled. It
161        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
162        characters, are recognized by isspace() and therefore were getting set in
163        these tables, and indeed these tables seem to approximate to ISO 8859. This
164        caused a problem in UTF-8 mode when pcre_study() was used to create a list
165        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
166        which of course cannot start UTF-8 characters. I have changed the code so
167        that only real ASCII characters (less than 128) and the correct starting
168        bytes for UTF-8 encodings are set for characters greater than 127 when in
169        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
170        altogether.)
171    
172    20. Added the /T option to pcretest so as to be able to run tests with non-
173        standard character tables, thus making it possible to include the tests
174        used for 19 above in the standard set of tests.
175    
176    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
177        reference to a subpattern the other side of a comment that contains an
178        opening parenthesis caused either an internal compiling error, or a
179        reference to the wrong subpattern.
180    
181    
182    Version 8.02 19-Mar-2010
183    ------------------------
184    
185    1.  The Unicode data tables have been updated to Unicode 5.2.0.
186    
187    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
188        configured.
189    
190    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
191        original author of that file, following a query about its status.
192    
193    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
194        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
195    
196    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
197        quantifier applied to a forward-referencing subroutine call, could compile
198        incorrect code or give the error "internal error: previously-checked
199        referenced subpattern not found".
200    
201    6.  Both MS Visual Studio and Symbian OS have problems with initializing
202        variables to point to external functions. For these systems, therefore,
203        pcre_malloc etc. are now initialized to local functions that call the
204        relevant global functions.
205    
206    7.  There were two entries missing in the vectors called coptable and poptable
207        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
208        I've fixed the data, and added a kludgy way of testing at compile time that
209        the lengths are correct (equal to the number of opcodes).
210    
211    8.  Following on from 7, I added a similar kludge to check the length of the
212        eint vector in pcreposix.c.
213    
214    9.  Error texts for pcre_compile() are held as one long string to avoid too
215        much relocation at load time. To find a text, the string is searched,
216        counting zeros. There was no check for running off the end of the string,
217        which could happen if a new error number was added without updating the
218        string.
219    
220    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
221    
222    11. \K was not working if it appeared in an atomic group or in a group that
223        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
224        \K is "not well defined" if used in an assertion. PCRE now accepts it if
225        the assertion is positive, but not if it is negative.
226    
227    12. Change 11 fortuitously reduced the size of the stack frame used in the
228        "match()" function of pcre_exec.c by one pointer. Forthcoming
229        implementation of support for (*MARK) will need an extra pointer on the
230        stack; I have reserved it now, so that the stack frame size does not
231        decrease.
232    
233    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
234        item in branch that calls a recursion is a subroutine call - as in the
235        second branch in the above example - was incorrectly given the compile-
236        time error "recursive call could loop indefinitely" because pcre_compile()
237        was not correctly checking the subroutine for matching a non-empty string.
238    
239    14. The checks for overrunning compiling workspace could trigger after an
240        overrun had occurred. This is a "should never occur" error, but it can be
241        triggered by pathological patterns such as hundreds of nested parentheses.
242        The checks now trigger 100 bytes before the end of the workspace.
243    
244    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
245    
246    
247    Version 8.01 19-Jan-2010
248    ------------------------
249    
250  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
251      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
252      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
253      subpatterns).      subpatterns). This could cause incorrect "no match" results.
254    
255  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
256      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 304  Version 8.01 11-Dec-09
304      custom one, because of the following reported problem in Windows:      custom one, because of the following reported problem in Windows:
305    
306        - libbz2 uses the Pascal calling convention (WINAPI) for the functions        - libbz2 uses the Pascal calling convention (WINAPI) for the functions
307          under Win32.            under Win32.
308        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
309          therefore missing the function definition.            therefore missing the function definition.
310        - The compiler thus generates a "C" signature for the test function.        - The compiler thus generates a "C" signature for the test function.
311        - The linker fails to find the "C" function.        - The linker fails to find the "C" function.
312        - PCRE fails to configure if asked to do so against libbz2.        - PCRE fails to configure if asked to do so against libbz2.
313    
314    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
315        messages were output:
316    
317          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
318          rerunning libtoolize, to keep the correct libtool macros in-tree.
319          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
320    
321        I have done both of these things.
322    
323    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
324        most of the time, it *can* run out if it is given a pattern that contains a
325        runaway infinite recursion. I updated the discussion in the pcrestack man
326        page.
327    
328    13. Now that we have gone to the x.xx style of version numbers, the minor
329        version may start with zero. Using 08 or 09 is a bad idea because users
330        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
331        interpreted as invalid octal numbers. I've updated the previous comment in
332        configure.ac, and also added a check that gives an error if 08 or 09 are
333        used.
334    
335    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
336        causing partial matching to fail when the end of the subject matched \W
337        in a UTF-8 pattern where \W was quantified with a minimum of 3.
338    
339    15. There were some discrepancies between the declarations in pcre_internal.h
340        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
341        their definitions. The declarations used "const uschar *" and the
342        definitions used USPTR. Even though USPTR is normally defined as "const
343        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
344        reported that: "This difference in casting confuses some C++ compilers, for
345        example, SunCC recognizes above declarations as different functions and
346        generates broken code for hbpcre." I have changed the declarations to use
347        USPTR.
348    
349    16. GNU libtool is named differently on some systems. The autogen.sh script now
350        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
351        (FreeBSD).
352    
353    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
354        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
355        comment: "Figure out how to create a longlong from a string: strtoll and
356        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
357        instance, but it only takes 2 args instead of 3!"
358    
359    18. A subtle bug concerned with back references has been fixed by a change of
360        specification, with a corresponding code fix. A pattern such as
361        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
362        refers, was giving matches when it shouldn't. For example, xa=xaaa would
363        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
364        same bug. Such groups have to be quantified to be useful, or contained
365        inside another quantified group. (If there's no repetition, the reference
366        can never match.) The problem arises because, having left the group and
367        moved on to the rest of the pattern, a later failure that backtracks into
368        the group uses the captured value from the final iteration of the group
369        rather than the correct earlier one. I have fixed this in PCRE by forcing
370        any group that contains a reference to itself to be an atomic group; that
371        is, there cannot be any backtracking into it once it has completed. This is
372        similar to recursive and subroutine calls.
373    
374    
375  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
376  ----------------------  ----------------------

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