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revision 473 by ph10, Sat Jan 2 12:40:07 2010 UTC revision 505 by ph10, Tue Mar 9 16:50:47 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.01 11-Dec-09  Version 8.02 01-Mar-2010
5  ----------------------  ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
8    
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
11    
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
14    
15    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
16        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
17    
18    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
19        quantifier applied to a forward-referencing subroutine call, could compile
20        incorrect code or give the error "internal error: previously-checked
21        referenced subpattern not found".
22    
23    6.  Both MS Visual Studio and Symbian OS have problems with initializing
24        variables to point to external functions. For these systems, therefore,
25        pcre_malloc etc. are now initialized to local functions that call the
26        relevant global functions.
27    
28    7.  There were two entries missing in the vectors called coptable and poptable
29        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
30        I've fixed the data, and added a kludgy way of testing at compile time that
31        the lengths are correct (equal to the number of opcodes).
32    
33    8.  Following on from 7, I added a similar kludge to check the length of the
34        eint vector in pcreposix.c.
35    
36    9.  Error texts for pcre_compile() are held as one long string to avoid too
37        much relocation at load time. To find a text, the string is searched,
38        counting zeros. There was no check for running off the end of the string,
39        which could happen if a new error number was added without updating the
40        string.
41    
42    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
43    
44    11. \K was not working if it appeared in an atomic group or in a group that
45        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
46        \K is "not well defined" if used in an assertion. PCRE now accepts it if
47        the assertion is positive, but not if it is negative.
48    
49    12. Change 11 fortuitously reduced the size of the stack frame used in the
50        "match()" function of pcre_exec.c by one pointer. Forthcoming
51        implementation of support for (*MARK) will need an extra pointer on the
52        stack; I have reserved it now, so that the stack frame size does not
53        decrease.
54    
55    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
56        item in branch that calls a recursion is a subroutine call - as in the
57        second branch in the above example - was incorrectly given the compile-
58        time error "recursive call could loop indefinitely" because pcre_compile()
59        was not correctly checking the subroutine for matching a non-empty string.
60    
61    14. The checks for overrunning compiling workspace could trigger after an
62        overrun had occurred. This is a "should never occur" error, but it can be
63        triggered by pathological patterns such as hundreds of nested parentheses.
64        The checks now trigger 100 bytes before the end of the workspace.
65    
66    
67    Version 8.01 19-Jan-2010
68    ------------------------
69    
70  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
71      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
72      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
73      subpatterns).      subpatterns). This could cause incorrect "no match" results.
74    
75  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
76      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 27  Version 8.01 11-Dec-09 Line 90  Version 8.01 11-Dec-09
90      unpredictable results occurred, instead of the error return      unpredictable results occurred, instead of the error return
91      PCRE_ERROR_DFA_UITEM.      PCRE_ERROR_DFA_UITEM.
92    
93    5.  The C++ GlobalReplace function was not working like Perl for the special
94        situation when an empty string is matched. It now does the fancy magic
95        stuff that is necessary.
96    
97    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
98        removed. (These were left over from very, very early versions of PCRE.)
99    
100    7.  Some cosmetic changes to the code to make life easier when compiling it
101        as part of something else:
102    
103        (a) Change DEBUG to PCRE_DEBUG.
104    
105        (b) In pcre_compile(), rename the member of the "branch_chain" structure
106            called "current" as "current_branch", to prevent a collision with the
107            Linux macro when compiled as a kernel module.
108    
109        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
110            prevent a collision with the Linux macro when compiled as a kernel
111            module.
112    
113    8.  In pcre_compile() there are some checks for integer overflows that used to
114        cast potentially large values to (double). This has been changed to that
115        when building, a check for int64_t is made, and if it is found, it is used
116        instead, thus avoiding the use of floating point arithmetic. (There is no
117        other use of FP in PCRE.) If int64_t is not found, the fallback is to
118        double.
119    
120    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
121        2005 (difference between two addresses compared to an unsigned value).
122    
123    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
124        custom one, because of the following reported problem in Windows:
125    
126          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
127              under Win32.
128          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
129              therefore missing the function definition.
130          - The compiler thus generates a "C" signature for the test function.
131          - The linker fails to find the "C" function.
132          - PCRE fails to configure if asked to do so against libbz2.
133    
134    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
135        messages were output:
136    
137          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
138          rerunning libtoolize, to keep the correct libtool macros in-tree.
139          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
140    
141        I have done both of these things.
142    
143    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
144        most of the time, it *can* run out if it is given a pattern that contains a
145        runaway infinite recursion. I updated the discussion in the pcrestack man
146        page.
147    
148    13. Now that we have gone to the x.xx style of version numbers, the minor
149        version may start with zero. Using 08 or 09 is a bad idea because users
150        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
151        interpreted as invalid octal numbers. I've updated the previous comment in
152        configure.ac, and also added a check that gives an error if 08 or 09 are
153        used.
154    
155    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
156        causing partial matching to fail when the end of the subject matched \W
157        in a UTF-8 pattern where \W was quantified with a minimum of 3.
158    
159    15. There were some discrepancies between the declarations in pcre_internal.h
160        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
161        their definitions. The declarations used "const uschar *" and the
162        definitions used USPTR. Even though USPTR is normally defined as "const
163        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
164        reported that: "This difference in casting confuses some C++ compilers, for
165        example, SunCC recognizes above declarations as different functions and
166        generates broken code for hbpcre." I have changed the declarations to use
167        USPTR.
168    
169    16. GNU libtool is named differently on some systems. The autogen.sh script now
170        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
171        (FreeBSD).
172    
173    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
174        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
175        comment: "Figure out how to create a longlong from a string: strtoll and
176        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
177        instance, but it only takes 2 args instead of 3!"
178    
179    18. A subtle bug concerned with back references has been fixed by a change of
180        specification, with a corresponding code fix. A pattern such as
181        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
182        refers, was giving matches when it shouldn't. For example, xa=xaaa would
183        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
184        same bug. Such groups have to be quantified to be useful, or contained
185        inside another quantified group. (If there's no repetition, the reference
186        can never match.) The problem arises because, having left the group and
187        moved on to the rest of the pattern, a later failure that backtracks into
188        the group uses the captured value from the final iteration of the group
189        rather than the correct earlier one. I have fixed this in PCRE by forcing
190        any group that contains a reference to itself to be an atomic group; that
191        is, there cannot be any backtracking into it once it has completed. This is
192        similar to recursive and subroutine calls.
193    
194    
195  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
196  ----------------------  ----------------------

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