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revision 472 by ph10, Fri Dec 11 16:42:50 2009 UTC revision 538 by ph10, Wed Jun 9 19:30:57 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.01 11-Dec-09  Version 8.10 03-Jun-2010
5  ----------------------  ------------------------
6    
7  1.  If a pattern contained a conditional subpattern with only one branch (in  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8      particular, this includes all (DEFINE) patterns), a call to pcre_study()      THEN.
9      computed the wrong minimum data length (which is of course zero for such  
10      subpatterns).  2.  (*ACCEPT) was not working when inside an atomic group.
11    
12    3.  Inside a character class, \B is treated as a literal by default, but
13        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14        causes the error). The code is unchanged, but I tidied the documentation.
15    
16    4.  Inside a character class, PCRE always treated \R and \X as literals,
17        whereas Perl faults them if its -w option is set. I have changed PCRE so
18        that it faults them when PCRE_EXTRA is set.
19    
20    5.  Added support for \N, which always matches any character other than
21        newline. (It is the same as "." when PCRE_DOTALL is not set.)
22    
23    6.  When compiling pcregrep with newer versions of gcc which may have
24        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25        declared with attribute warn_unused_result" were given. Just casting the
26        result to (void) does not stop the warnings; a more elaborate fudge is
27        needed. I've used a macro to implement this.
28    
29    7.  Minor change to pcretest.c to avoid a compiler warning.
30    
31    8.  Added four artifical Unicode properties to help with an option to make
32        \s etc use properties (see next item). The new properties are: Xan
33        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
34    
35    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
36        use Unicode properties. (*UCP) at the start of a pattern can be used to set
37        this option. Modified pcretest to add /W to test this facility. Added
38        REG_UCP to make it available via the POSIX interface.
39    
40    10. Added --line-buffered to pcregrep.
41    
42    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
43        studied, and the match started with a letter with a code point greater than
44        127 whose first byte was different to the first byte of the other case of
45        the letter, the other case of this starting letter was not recognized
46        (#976).
47    
48    12. If a pattern that was studied started with a repeated Unicode property
49        test, for example, \p{Nd}+, there was the theoretical possibility of
50        setting up an incorrect bitmap of starting bytes, but fortunately it could
51        not have actually happened in practice until change 8 above was made (it
52        added property types that matched character-matching opcodes).
53    
54    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
55        possible starting bytes for non-anchored patterns.
56    
57    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
58        \R, and also a number of cases that involve Unicode properties, both
59        explicit and implicit when PCRE_UCP is set.
60    
61    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
62        input, it could crash or give wrong results if characters with values
63        greater than 0xc0 were present in the subject string. (Detail: it assumed
64        UTF-8 input when processing these items.)
65    
66    16. Added a lot of (int) casts to avoid compiler warnings in systems where
67        size_t is 64-bit (#991).
68    
69    17. Added a check for running out of memory when PCRE is compiled with
70        --disable-stack-for-recursion (#990).
71    
72    18. If the last data line in a file for pcretest does not have a newline on
73        the end, a newline was missing in the output.
74    
75  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of  19. The default pcre_chartables.c file recognizes only ASCII characters (values
76        less than 128) in its various bitmaps. However, there is a facility for
77        generating tables according to the current locale when PCRE is compiled. It
78        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
79        characters, are recognized by isspace() and therefore were getting set in
80        these tables. This caused a problem in UTF-8 mode when pcre_study() was
81        used to create a list of bytes that can start a match. For \s, it was
82        including 0x85 and 0xa0, which of course cannot start UTF-8 characters. I
83        have changed the code so that only real ASCII characters (less than 128)
84        are set in this case because the \s etc escapes are documented as
85        recognizing only ASCII characters. (When PCRE_UCP is set - see 9 above -
86        the code is different altogether.)
87    
88    
89    Version 8.02 19-Mar-2010
90    ------------------------
91    
92    1.  The Unicode data tables have been updated to Unicode 5.2.0.
93    
94    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
95        configured.
96    
97    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
98        original author of that file, following a query about its status.
99    
100    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
101        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
102    
103    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
104        quantifier applied to a forward-referencing subroutine call, could compile
105        incorrect code or give the error "internal error: previously-checked
106        referenced subpattern not found".
107    
108    6.  Both MS Visual Studio and Symbian OS have problems with initializing
109        variables to point to external functions. For these systems, therefore,
110        pcre_malloc etc. are now initialized to local functions that call the
111        relevant global functions.
112    
113    7.  There were two entries missing in the vectors called coptable and poptable
114        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
115        I've fixed the data, and added a kludgy way of testing at compile time that
116        the lengths are correct (equal to the number of opcodes).
117    
118    8.  Following on from 7, I added a similar kludge to check the length of the
119        eint vector in pcreposix.c.
120    
121    9.  Error texts for pcre_compile() are held as one long string to avoid too
122        much relocation at load time. To find a text, the string is searched,
123        counting zeros. There was no check for running off the end of the string,
124        which could happen if a new error number was added without updating the
125        string.
126    
127    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
128    
129    11. \K was not working if it appeared in an atomic group or in a group that
130        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
131        \K is "not well defined" if used in an assertion. PCRE now accepts it if
132        the assertion is positive, but not if it is negative.
133    
134    12. Change 11 fortuitously reduced the size of the stack frame used in the
135        "match()" function of pcre_exec.c by one pointer. Forthcoming
136        implementation of support for (*MARK) will need an extra pointer on the
137        stack; I have reserved it now, so that the stack frame size does not
138        decrease.
139    
140    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
141        item in branch that calls a recursion is a subroutine call - as in the
142        second branch in the above example - was incorrectly given the compile-
143        time error "recursive call could loop indefinitely" because pcre_compile()
144        was not correctly checking the subroutine for matching a non-empty string.
145    
146    14. The checks for overrunning compiling workspace could trigger after an
147        overrun had occurred. This is a "should never occur" error, but it can be
148        triggered by pathological patterns such as hundreds of nested parentheses.
149        The checks now trigger 100 bytes before the end of the workspace.
150    
151    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
152    
153    
154    Version 8.01 19-Jan-2010
155    ------------------------
156    
157    1.  If a pattern contained a conditional subpattern with only one branch (in
158        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
159        computed the wrong minimum data length (which is of course zero for such
160        subpatterns). This could cause incorrect "no match" results.
161    
162    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
163      the pattern is reset in the first branch, pcre_compile() failed with      the pattern is reset in the first branch, pcre_compile() failed with
164      "internal error: code overflow at offset...". This happened only when      "internal error: code overflow at offset...". This happened only when
165      the reset was to the original external option setting. (An optimization      the reset was to the original external option setting. (An optimization
166      abstracts leading options settings into an external setting, which was the      abstracts leading options settings into an external setting, which was the
167      cause of this.)      cause of this.)
168    
169    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
170        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
171        assertion pattern did not match (meaning that the assertion was true), it
172        was incorrectly treated as false if the SKIP had been reached during the
173        matching. This also applied to assertions used as conditions.
174    
175    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
176        assertion subpattern, including such a pattern used as a condition,
177        unpredictable results occurred, instead of the error return
178        PCRE_ERROR_DFA_UITEM.
179    
180    5.  The C++ GlobalReplace function was not working like Perl for the special
181        situation when an empty string is matched. It now does the fancy magic
182        stuff that is necessary.
183    
184    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
185        removed. (These were left over from very, very early versions of PCRE.)
186    
187    7.  Some cosmetic changes to the code to make life easier when compiling it
188        as part of something else:
189    
190        (a) Change DEBUG to PCRE_DEBUG.
191    
192        (b) In pcre_compile(), rename the member of the "branch_chain" structure
193            called "current" as "current_branch", to prevent a collision with the
194            Linux macro when compiled as a kernel module.
195    
196        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
197            prevent a collision with the Linux macro when compiled as a kernel
198            module.
199    
200    8.  In pcre_compile() there are some checks for integer overflows that used to
201        cast potentially large values to (double). This has been changed to that
202        when building, a check for int64_t is made, and if it is found, it is used
203        instead, thus avoiding the use of floating point arithmetic. (There is no
204        other use of FP in PCRE.) If int64_t is not found, the fallback is to
205        double.
206    
207    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
208        2005 (difference between two addresses compared to an unsigned value).
209    
210    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
211        custom one, because of the following reported problem in Windows:
212    
213          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
214              under Win32.
215          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
216              therefore missing the function definition.
217          - The compiler thus generates a "C" signature for the test function.
218          - The linker fails to find the "C" function.
219          - PCRE fails to configure if asked to do so against libbz2.
220    
221    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
222        messages were output:
223    
224          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
225          rerunning libtoolize, to keep the correct libtool macros in-tree.
226          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
227    
228        I have done both of these things.
229    
230    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
231        most of the time, it *can* run out if it is given a pattern that contains a
232        runaway infinite recursion. I updated the discussion in the pcrestack man
233        page.
234    
235    13. Now that we have gone to the x.xx style of version numbers, the minor
236        version may start with zero. Using 08 or 09 is a bad idea because users
237        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
238        interpreted as invalid octal numbers. I've updated the previous comment in
239        configure.ac, and also added a check that gives an error if 08 or 09 are
240        used.
241    
242    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
243        causing partial matching to fail when the end of the subject matched \W
244        in a UTF-8 pattern where \W was quantified with a minimum of 3.
245    
246    15. There were some discrepancies between the declarations in pcre_internal.h
247        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
248        their definitions. The declarations used "const uschar *" and the
249        definitions used USPTR. Even though USPTR is normally defined as "const
250        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
251        reported that: "This difference in casting confuses some C++ compilers, for
252        example, SunCC recognizes above declarations as different functions and
253        generates broken code for hbpcre." I have changed the declarations to use
254        USPTR.
255    
256    16. GNU libtool is named differently on some systems. The autogen.sh script now
257        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
258        (FreeBSD).
259    
260    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
261        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
262        comment: "Figure out how to create a longlong from a string: strtoll and
263        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
264        instance, but it only takes 2 args instead of 3!"
265    
266    18. A subtle bug concerned with back references has been fixed by a change of
267        specification, with a corresponding code fix. A pattern such as
268        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
269        refers, was giving matches when it shouldn't. For example, xa=xaaa would
270        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
271        same bug. Such groups have to be quantified to be useful, or contained
272        inside another quantified group. (If there's no repetition, the reference
273        can never match.) The problem arises because, having left the group and
274        moved on to the rest of the pattern, a later failure that backtracks into
275        the group uses the captured value from the final iteration of the group
276        rather than the correct earlier one. I have fixed this in PCRE by forcing
277        any group that contains a reference to itself to be an atomic group; that
278        is, there cannot be any backtracking into it once it has completed. This is
279        similar to recursive and subroutine calls.
280    
281    
282  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
283  ----------------------  ----------------------

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