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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.01 11-Dec-09  Version 8.10 03 May-2010
5  ----------------------  ------------------------
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.
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.
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.
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.)
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.
29    7.  Minor change to pcretest.c to avoid a compiler warning.
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).
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.
40  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of  10. Added --line-buffered to pcregrep.
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.
48    Version 8.02 19-Mar-2010
49    ------------------------
51    1.  The Unicode data tables have been updated to Unicode 5.2.0.
53    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
54        configured.
56    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
57        original author of that file, following a query about its status.
59    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
60        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
62    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
63        quantifier applied to a forward-referencing subroutine call, could compile
64        incorrect code or give the error "internal error: previously-checked
65        referenced subpattern not found".
67    6.  Both MS Visual Studio and Symbian OS have problems with initializing
68        variables to point to external functions. For these systems, therefore,
69        pcre_malloc etc. are now initialized to local functions that call the
70        relevant global functions.
72    7.  There were two entries missing in the vectors called coptable and poptable
73        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
74        I've fixed the data, and added a kludgy way of testing at compile time that
75        the lengths are correct (equal to the number of opcodes).
77    8.  Following on from 7, I added a similar kludge to check the length of the
78        eint vector in pcreposix.c.
80    9.  Error texts for pcre_compile() are held as one long string to avoid too
81        much relocation at load time. To find a text, the string is searched,
82        counting zeros. There was no check for running off the end of the string,
83        which could happen if a new error number was added without updating the
84        string.
86    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
88    11. \K was not working if it appeared in an atomic group or in a group that
89        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
90        \K is "not well defined" if used in an assertion. PCRE now accepts it if
91        the assertion is positive, but not if it is negative.
93    12. Change 11 fortuitously reduced the size of the stack frame used in the
94        "match()" function of pcre_exec.c by one pointer. Forthcoming
95        implementation of support for (*MARK) will need an extra pointer on the
96        stack; I have reserved it now, so that the stack frame size does not
97        decrease.
99    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
100        item in branch that calls a recursion is a subroutine call - as in the
101        second branch in the above example - was incorrectly given the compile-
102        time error "recursive call could loop indefinitely" because pcre_compile()
103        was not correctly checking the subroutine for matching a non-empty string.
105    14. The checks for overrunning compiling workspace could trigger after an
106        overrun had occurred. This is a "should never occur" error, but it can be
107        triggered by pathological patterns such as hundreds of nested parentheses.
108        The checks now trigger 100 bytes before the end of the workspace.
110    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
113    Version 8.01 19-Jan-2010
114    ------------------------
116    1.  If a pattern contained a conditional subpattern with only one branch (in
117        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
118        computed the wrong minimum data length (which is of course zero for such
119        subpatterns). This could cause incorrect "no match" results.
121    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
122      the pattern is reset in the first branch, pcre_compile() failed with      the pattern is reset in the first branch, pcre_compile() failed with
123      "internal error: code overflow at offset...". This happened only when      "internal error: code overflow at offset...". This happened only when
124      the reset was to the original external option setting. (An optimization      the reset was to the original external option setting. (An optimization
125      abstracts leading options settings into an external setting, which was the      abstracts leading options settings into an external setting, which was the
126      cause of this.)      cause of this.)
128    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
129        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
130        assertion pattern did not match (meaning that the assertion was true), it
131        was incorrectly treated as false if the SKIP had been reached during the
132        matching. This also applied to assertions used as conditions.
134    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
135        assertion subpattern, including such a pattern used as a condition,
136        unpredictable results occurred, instead of the error return
139    5.  The C++ GlobalReplace function was not working like Perl for the special
140        situation when an empty string is matched. It now does the fancy magic
141        stuff that is necessary.
143    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
144        removed. (These were left over from very, very early versions of PCRE.)
146    7.  Some cosmetic changes to the code to make life easier when compiling it
147        as part of something else:
149        (a) Change DEBUG to PCRE_DEBUG.
151        (b) In pcre_compile(), rename the member of the "branch_chain" structure
152            called "current" as "current_branch", to prevent a collision with the
153            Linux macro when compiled as a kernel module.
155        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
156            prevent a collision with the Linux macro when compiled as a kernel
157            module.
159    8.  In pcre_compile() there are some checks for integer overflows that used to
160        cast potentially large values to (double). This has been changed to that
161        when building, a check for int64_t is made, and if it is found, it is used
162        instead, thus avoiding the use of floating point arithmetic. (There is no
163        other use of FP in PCRE.) If int64_t is not found, the fallback is to
164        double.
166    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
167        2005 (difference between two addresses compared to an unsigned value).
169    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
170        custom one, because of the following reported problem in Windows:
172          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
173              under Win32.
174          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
175              therefore missing the function definition.
176          - The compiler thus generates a "C" signature for the test function.
177          - The linker fails to find the "C" function.
178          - PCRE fails to configure if asked to do so against libbz2.
180    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
181        messages were output:
183          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
184          rerunning libtoolize, to keep the correct libtool macros in-tree.
185          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
187        I have done both of these things.
189    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
190        most of the time, it *can* run out if it is given a pattern that contains a
191        runaway infinite recursion. I updated the discussion in the pcrestack man
192        page.
194    13. Now that we have gone to the x.xx style of version numbers, the minor
195        version may start with zero. Using 08 or 09 is a bad idea because users
196        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
197        interpreted as invalid octal numbers. I've updated the previous comment in
198        configure.ac, and also added a check that gives an error if 08 or 09 are
199        used.
201    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
202        causing partial matching to fail when the end of the subject matched \W
203        in a UTF-8 pattern where \W was quantified with a minimum of 3.
205    15. There were some discrepancies between the declarations in pcre_internal.h
206        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
207        their definitions. The declarations used "const uschar *" and the
208        definitions used USPTR. Even though USPTR is normally defined as "const
209        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
210        reported that: "This difference in casting confuses some C++ compilers, for
211        example, SunCC recognizes above declarations as different functions and
212        generates broken code for hbpcre." I have changed the declarations to use
213        USPTR.
215    16. GNU libtool is named differently on some systems. The autogen.sh script now
216        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
217        (FreeBSD).
219    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
220        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
221        comment: "Figure out how to create a longlong from a string: strtoll and
222        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
223        instance, but it only takes 2 args instead of 3!"
225    18. A subtle bug concerned with back references has been fixed by a change of
226        specification, with a corresponding code fix. A pattern such as
227        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
228        refers, was giving matches when it shouldn't. For example, xa=xaaa would
229        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
230        same bug. Such groups have to be quantified to be useful, or contained
231        inside another quantified group. (If there's no repetition, the reference
232        can never match.) The problem arises because, having left the group and
233        moved on to the rest of the pattern, a later failure that backtracks into
234        the group uses the captured value from the final iteration of the group
235        rather than the correct earlier one. I have fixed this in PCRE by forcing
236        any group that contains a reference to itself to be an atomic group; that
237        is, there cannot be any backtracking into it once it has completed. This is
238        similar to recursive and subroutine calls.
241  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
242  ----------------------  ----------------------

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