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revision 475 by ph10, Sat Jan 2 18:21:30 2010 UTC revision 553 by ph10, Fri Oct 22 15:57:50 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    
44    Version 8.10 25-Jun-2010
45    ------------------------
46    
47    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
48        THEN.
49    
50    2.  (*ACCEPT) was not working when inside an atomic group.
51    
52    3.  Inside a character class, \B is treated as a literal by default, but
53        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
54        causes the error). The code is unchanged, but I tidied the documentation.
55    
56    4.  Inside a character class, PCRE always treated \R and \X as literals,
57        whereas Perl faults them if its -w option is set. I have changed PCRE so
58        that it faults them when PCRE_EXTRA is set.
59    
60    5.  Added support for \N, which always matches any character other than
61        newline. (It is the same as "." when PCRE_DOTALL is not set.)
62    
63    6.  When compiling pcregrep with newer versions of gcc which may have
64        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
65        declared with attribute warn_unused_result" were given. Just casting the
66        result to (void) does not stop the warnings; a more elaborate fudge is
67        needed. I've used a macro to implement this.
68    
69    7.  Minor change to pcretest.c to avoid a compiler warning.
70    
71    8.  Added four artifical Unicode properties to help with an option to make
72        \s etc use properties (see next item). The new properties are: Xan
73        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
74    
75    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
76        use Unicode properties. (*UCP) at the start of a pattern can be used to set
77        this option. Modified pcretest to add /W to test this facility. Added
78        REG_UCP to make it available via the POSIX interface.
79    
80    10. Added --line-buffered to pcregrep.
81    
82    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
83        studied, and the match started with a letter with a code point greater than
84        127 whose first byte was different to the first byte of the other case of
85        the letter, the other case of this starting letter was not recognized
86        (#976).
87    
88    12. If a pattern that was studied started with a repeated Unicode property
89        test, for example, \p{Nd}+, there was the theoretical possibility of
90        setting up an incorrect bitmap of starting bytes, but fortunately it could
91        not have actually happened in practice until change 8 above was made (it
92        added property types that matched character-matching opcodes).
93    
94    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
95        possible starting bytes for non-anchored patterns.
96    
97    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
98        \R, and also a number of cases that involve Unicode properties, both
99        explicit and implicit when PCRE_UCP is set.
100    
101    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
102        input, it could crash or give wrong results if characters with values
103        greater than 0xc0 were present in the subject string. (Detail: it assumed
104        UTF-8 input when processing these items.)
105    
106    16. Added a lot of (int) casts to avoid compiler warnings in systems where
107        size_t is 64-bit (#991).
108    
109    17. Added a check for running out of memory when PCRE is compiled with
110        --disable-stack-for-recursion (#990).
111    
112    18. If the last data line in a file for pcretest does not have a newline on
113        the end, a newline was missing in the output.
114    
115    19. The default pcre_chartables.c file recognizes only ASCII characters (values
116        less than 128) in its various bitmaps. However, there is a facility for
117        generating tables according to the current locale when PCRE is compiled. It
118        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
119        characters, are recognized by isspace() and therefore were getting set in
120        these tables, and indeed these tables seem to approximate to ISO 8859. This
121        caused a problem in UTF-8 mode when pcre_study() was used to create a list
122        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
123        which of course cannot start UTF-8 characters. I have changed the code so
124        that only real ASCII characters (less than 128) and the correct starting
125        bytes for UTF-8 encodings are set for characters greater than 127 when in
126        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
127        altogether.)
128    
129    20. Added the /T option to pcretest so as to be able to run tests with non-
130        standard character tables, thus making it possible to include the tests
131        used for 19 above in the standard set of tests.
132    
133    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
134        reference to a subpattern the other side of a comment that contains an
135        opening parenthesis caused either an internal compiling error, or a
136        reference to the wrong subpattern.
137    
138    
139    Version 8.02 19-Mar-2010
140    ------------------------
141    
142    1.  The Unicode data tables have been updated to Unicode 5.2.0.
143    
144    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
145        configured.
146    
147    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
148        original author of that file, following a query about its status.
149    
150    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
151        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
152    
153    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
154        quantifier applied to a forward-referencing subroutine call, could compile
155        incorrect code or give the error "internal error: previously-checked
156        referenced subpattern not found".
157    
158    6.  Both MS Visual Studio and Symbian OS have problems with initializing
159        variables to point to external functions. For these systems, therefore,
160        pcre_malloc etc. are now initialized to local functions that call the
161        relevant global functions.
162    
163    7.  There were two entries missing in the vectors called coptable and poptable
164        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
165        I've fixed the data, and added a kludgy way of testing at compile time that
166        the lengths are correct (equal to the number of opcodes).
167    
168    8.  Following on from 7, I added a similar kludge to check the length of the
169        eint vector in pcreposix.c.
170    
171    9.  Error texts for pcre_compile() are held as one long string to avoid too
172        much relocation at load time. To find a text, the string is searched,
173        counting zeros. There was no check for running off the end of the string,
174        which could happen if a new error number was added without updating the
175        string.
176    
177    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
178    
179    11. \K was not working if it appeared in an atomic group or in a group that
180        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
181        \K is "not well defined" if used in an assertion. PCRE now accepts it if
182        the assertion is positive, but not if it is negative.
183    
184    12. Change 11 fortuitously reduced the size of the stack frame used in the
185        "match()" function of pcre_exec.c by one pointer. Forthcoming
186        implementation of support for (*MARK) will need an extra pointer on the
187        stack; I have reserved it now, so that the stack frame size does not
188        decrease.
189    
190    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
191        item in branch that calls a recursion is a subroutine call - as in the
192        second branch in the above example - was incorrectly given the compile-
193        time error "recursive call could loop indefinitely" because pcre_compile()
194        was not correctly checking the subroutine for matching a non-empty string.
195    
196    14. The checks for overrunning compiling workspace could trigger after an
197        overrun had occurred. This is a "should never occur" error, but it can be
198        triggered by pathological patterns such as hundreds of nested parentheses.
199        The checks now trigger 100 bytes before the end of the workspace.
200    
201    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
202    
203    
204    Version 8.01 19-Jan-2010
205    ------------------------
206    
207  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
208      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
209      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
210      subpatterns).      subpatterns). This could cause incorrect "no match" results.
211    
212  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
213      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 26  Version 8.01 11-Dec-09 Line 226  Version 8.01 11-Dec-09
226      assertion subpattern, including such a pattern used as a condition,      assertion subpattern, including such a pattern used as a condition,
227      unpredictable results occurred, instead of the error return      unpredictable results occurred, instead of the error return
228      PCRE_ERROR_DFA_UITEM.      PCRE_ERROR_DFA_UITEM.
229    
230  5.  The C++ GlobalReplace function was not working like Perl for the special  5.  The C++ GlobalReplace function was not working like Perl for the special
231      situation when an empty string is matched. It now does the fancy magic      situation when an empty string is matched. It now does the fancy magic
232      stuff that is necessary.      stuff that is necessary.
233    
234  6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been  6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
235      removed. (These were left over from very, very early versions of PCRE.)      removed. (These were left over from very, very early versions of PCRE.)
236    
237  7.  Some cosmetic changes to the code to make life easier when compiling it  7.  Some cosmetic changes to the code to make life easier when compiling it
238      as part of something else:      as part of something else:
239    
240      (a) Change DEBUG to PCRE_DEBUG.      (a) Change DEBUG to PCRE_DEBUG.
241    
242      (b) In pcre_compile(), rename the member of the "branch_chain" structure      (b) In pcre_compile(), rename the member of the "branch_chain" structure
243          called "current" as "current_branch", to prevent a collision with the          called "current" as "current_branch", to prevent a collision with the
244          Linux macro when compiled as a kernel module.          Linux macro when compiled as a kernel module.
245    
246      (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to      (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
247          prevent a collision with the Linux macro when compiled as a kernel          prevent a collision with the Linux macro when compiled as a kernel
248          module.          module.
249    
250  8.  In pcre_compile() there are some checks for integer overflows that used to  8.  In pcre_compile() there are some checks for integer overflows that used to
251      cast potentially large values to (double). This has been changed to that      cast potentially large values to (double). This has been changed to that
252      when building, a check for int64_t is made, and if it is found, it is used      when building, a check for int64_t is made, and if it is found, it is used
253      instead, thus avoiding the use of floating point arithmetic. (There is no      instead, thus avoiding the use of floating point arithmetic. (There is no
254      other use of FP in PCRE.) If int64_t is not found, the fallback is to      other use of FP in PCRE.) If int64_t is not found, the fallback is to
255      double.      double.
256    
257    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
258        2005 (difference between two addresses compared to an unsigned value).
259    
260    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
261        custom one, because of the following reported problem in Windows:
262    
263          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
264              under Win32.
265          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
266              therefore missing the function definition.
267          - The compiler thus generates a "C" signature for the test function.
268          - The linker fails to find the "C" function.
269          - PCRE fails to configure if asked to do so against libbz2.
270    
271    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
272        messages were output:
273    
274          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
275          rerunning libtoolize, to keep the correct libtool macros in-tree.
276          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
277    
278        I have done both of these things.
279    
280    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
281        most of the time, it *can* run out if it is given a pattern that contains a
282        runaway infinite recursion. I updated the discussion in the pcrestack man
283        page.
284    
285    13. Now that we have gone to the x.xx style of version numbers, the minor
286        version may start with zero. Using 08 or 09 is a bad idea because users
287        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
288        interpreted as invalid octal numbers. I've updated the previous comment in
289        configure.ac, and also added a check that gives an error if 08 or 09 are
290        used.
291    
292    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
293        causing partial matching to fail when the end of the subject matched \W
294        in a UTF-8 pattern where \W was quantified with a minimum of 3.
295    
296    15. There were some discrepancies between the declarations in pcre_internal.h
297        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
298        their definitions. The declarations used "const uschar *" and the
299        definitions used USPTR. Even though USPTR is normally defined as "const
300        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
301        reported that: "This difference in casting confuses some C++ compilers, for
302        example, SunCC recognizes above declarations as different functions and
303        generates broken code for hbpcre." I have changed the declarations to use
304        USPTR.
305    
306    16. GNU libtool is named differently on some systems. The autogen.sh script now
307        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
308        (FreeBSD).
309    
310    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
311        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
312        comment: "Figure out how to create a longlong from a string: strtoll and
313        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
314        instance, but it only takes 2 args instead of 3!"
315    
316    18. A subtle bug concerned with back references has been fixed by a change of
317        specification, with a corresponding code fix. A pattern such as
318        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
319        refers, was giving matches when it shouldn't. For example, xa=xaaa would
320        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
321        same bug. Such groups have to be quantified to be useful, or contained
322        inside another quantified group. (If there's no repetition, the reference
323        can never match.) The problem arises because, having left the group and
324        moved on to the rest of the pattern, a later failure that backtracks into
325        the group uses the captured value from the final iteration of the group
326        rather than the correct earlier one. I have fixed this in PCRE by forcing
327        any group that contains a reference to itself to be an atomic group; that
328        is, there cannot be any backtracking into it once it has completed. This is
329        similar to recursive and subroutine calls.
330    
331    
332  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09

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