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revision 473 by ph10, Sat Jan 2 12:40:07 2010 UTC revision 569 by ph10, Sun Nov 7 16:14:50 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.01 11-Dec-09  Version 8.11 10-Oct-2010
5  ----------------------  ------------------------
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".
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).
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.)
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").
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.]
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().
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.
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.
60    9.  Added --match-limit and --recursion-limit to pcregrep.
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
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.
67    12. Added an optional parentheses number to the -o and --only-matching options
68        of pcregrep.
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:
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).
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.)
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.
86    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
87        as a starting offset was within the subject string. There is now a new
88        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
89        negative or greater than the length of the string. In order to test this,
90        pcretest is extended to allow the setting of negative starting offsets.
92    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
93        starting offset points to the beginning of a UTF-8 character was
94        unnecessarily clumsy. I tidied it up.
96    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
97        bad UTF-8 sequence and one that is incomplete.
100    Version 8.10 25-Jun-2010
101    ------------------------
103    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
104        THEN.
106    2.  (*ACCEPT) was not working when inside an atomic group.
108    3.  Inside a character class, \B is treated as a literal by default, but
109        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
110        causes the error). The code is unchanged, but I tidied the documentation.
112    4.  Inside a character class, PCRE always treated \R and \X as literals,
113        whereas Perl faults them if its -w option is set. I have changed PCRE so
114        that it faults them when PCRE_EXTRA is set.
116    5.  Added support for \N, which always matches any character other than
117        newline. (It is the same as "." when PCRE_DOTALL is not set.)
119    6.  When compiling pcregrep with newer versions of gcc which may have
120        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
121        declared with attribute warn_unused_result" were given. Just casting the
122        result to (void) does not stop the warnings; a more elaborate fudge is
123        needed. I've used a macro to implement this.
125    7.  Minor change to pcretest.c to avoid a compiler warning.
127    8.  Added four artifical Unicode properties to help with an option to make
128        \s etc use properties (see next item). The new properties are: Xan
129        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
131    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
132        use Unicode properties. (*UCP) at the start of a pattern can be used to set
133        this option. Modified pcretest to add /W to test this facility. Added
134        REG_UCP to make it available via the POSIX interface.
136    10. Added --line-buffered to pcregrep.
138    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
139        studied, and the match started with a letter with a code point greater than
140        127 whose first byte was different to the first byte of the other case of
141        the letter, the other case of this starting letter was not recognized
142        (#976).
144    12. If a pattern that was studied started with a repeated Unicode property
145        test, for example, \p{Nd}+, there was the theoretical possibility of
146        setting up an incorrect bitmap of starting bytes, but fortunately it could
147        not have actually happened in practice until change 8 above was made (it
148        added property types that matched character-matching opcodes).
150    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
151        possible starting bytes for non-anchored patterns.
153    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
154        \R, and also a number of cases that involve Unicode properties, both
155        explicit and implicit when PCRE_UCP is set.
157    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
158        input, it could crash or give wrong results if characters with values
159        greater than 0xc0 were present in the subject string. (Detail: it assumed
160        UTF-8 input when processing these items.)
162    16. Added a lot of (int) casts to avoid compiler warnings in systems where
163        size_t is 64-bit (#991).
165    17. Added a check for running out of memory when PCRE is compiled with
166        --disable-stack-for-recursion (#990).
168    18. If the last data line in a file for pcretest does not have a newline on
169        the end, a newline was missing in the output.
171    19. The default pcre_chartables.c file recognizes only ASCII characters (values
172        less than 128) in its various bitmaps. However, there is a facility for
173        generating tables according to the current locale when PCRE is compiled. It
174        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
175        characters, are recognized by isspace() and therefore were getting set in
176        these tables, and indeed these tables seem to approximate to ISO 8859. This
177        caused a problem in UTF-8 mode when pcre_study() was used to create a list
178        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
179        which of course cannot start UTF-8 characters. I have changed the code so
180        that only real ASCII characters (less than 128) and the correct starting
181        bytes for UTF-8 encodings are set for characters greater than 127 when in
182        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
183        altogether.)
185    20. Added the /T option to pcretest so as to be able to run tests with non-
186        standard character tables, thus making it possible to include the tests
187        used for 19 above in the standard set of tests.
189    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
190        reference to a subpattern the other side of a comment that contains an
191        opening parenthesis caused either an internal compiling error, or a
192        reference to the wrong subpattern.
195    Version 8.02 19-Mar-2010
196    ------------------------
198    1.  The Unicode data tables have been updated to Unicode 5.2.0.
200    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
201        configured.
203    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
204        original author of that file, following a query about its status.
206    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
207        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
209    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
210        quantifier applied to a forward-referencing subroutine call, could compile
211        incorrect code or give the error "internal error: previously-checked
212        referenced subpattern not found".
214    6.  Both MS Visual Studio and Symbian OS have problems with initializing
215        variables to point to external functions. For these systems, therefore,
216        pcre_malloc etc. are now initialized to local functions that call the
217        relevant global functions.
219    7.  There were two entries missing in the vectors called coptable and poptable
220        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
221        I've fixed the data, and added a kludgy way of testing at compile time that
222        the lengths are correct (equal to the number of opcodes).
224    8.  Following on from 7, I added a similar kludge to check the length of the
225        eint vector in pcreposix.c.
227    9.  Error texts for pcre_compile() are held as one long string to avoid too
228        much relocation at load time. To find a text, the string is searched,
229        counting zeros. There was no check for running off the end of the string,
230        which could happen if a new error number was added without updating the
231        string.
233    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
235    11. \K was not working if it appeared in an atomic group or in a group that
236        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
237        \K is "not well defined" if used in an assertion. PCRE now accepts it if
238        the assertion is positive, but not if it is negative.
240    12. Change 11 fortuitously reduced the size of the stack frame used in the
241        "match()" function of pcre_exec.c by one pointer. Forthcoming
242        implementation of support for (*MARK) will need an extra pointer on the
243        stack; I have reserved it now, so that the stack frame size does not
244        decrease.
246    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
247        item in branch that calls a recursion is a subroutine call - as in the
248        second branch in the above example - was incorrectly given the compile-
249        time error "recursive call could loop indefinitely" because pcre_compile()
250        was not correctly checking the subroutine for matching a non-empty string.
252    14. The checks for overrunning compiling workspace could trigger after an
253        overrun had occurred. This is a "should never occur" error, but it can be
254        triggered by pathological patterns such as hundreds of nested parentheses.
255        The checks now trigger 100 bytes before the end of the workspace.
257    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
260    Version 8.01 19-Jan-2010
261    ------------------------
263  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
264      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
265      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
266      subpatterns).      subpatterns). This could cause incorrect "no match" results.
268  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
269      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 283  Version 8.01 11-Dec-09
283      unpredictable results occurred, instead of the error return      unpredictable results occurred, instead of the error return
286    5.  The C++ GlobalReplace function was not working like Perl for the special
287        situation when an empty string is matched. It now does the fancy magic
288        stuff that is necessary.
290    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
291        removed. (These were left over from very, very early versions of PCRE.)
293    7.  Some cosmetic changes to the code to make life easier when compiling it
294        as part of something else:
296        (a) Change DEBUG to PCRE_DEBUG.
298        (b) In pcre_compile(), rename the member of the "branch_chain" structure
299            called "current" as "current_branch", to prevent a collision with the
300            Linux macro when compiled as a kernel module.
302        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
303            prevent a collision with the Linux macro when compiled as a kernel
304            module.
306    8.  In pcre_compile() there are some checks for integer overflows that used to
307        cast potentially large values to (double). This has been changed to that
308        when building, a check for int64_t is made, and if it is found, it is used
309        instead, thus avoiding the use of floating point arithmetic. (There is no
310        other use of FP in PCRE.) If int64_t is not found, the fallback is to
311        double.
313    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
314        2005 (difference between two addresses compared to an unsigned value).
316    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
317        custom one, because of the following reported problem in Windows:
319          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
320              under Win32.
321          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
322              therefore missing the function definition.
323          - The compiler thus generates a "C" signature for the test function.
324          - The linker fails to find the "C" function.
325          - PCRE fails to configure if asked to do so against libbz2.
327    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
328        messages were output:
330          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
331          rerunning libtoolize, to keep the correct libtool macros in-tree.
332          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
334        I have done both of these things.
336    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
337        most of the time, it *can* run out if it is given a pattern that contains a
338        runaway infinite recursion. I updated the discussion in the pcrestack man
339        page.
341    13. Now that we have gone to the x.xx style of version numbers, the minor
342        version may start with zero. Using 08 or 09 is a bad idea because users
343        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
344        interpreted as invalid octal numbers. I've updated the previous comment in
345        configure.ac, and also added a check that gives an error if 08 or 09 are
346        used.
348    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
349        causing partial matching to fail when the end of the subject matched \W
350        in a UTF-8 pattern where \W was quantified with a minimum of 3.
352    15. There were some discrepancies between the declarations in pcre_internal.h
353        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
354        their definitions. The declarations used "const uschar *" and the
355        definitions used USPTR. Even though USPTR is normally defined as "const
356        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
357        reported that: "This difference in casting confuses some C++ compilers, for
358        example, SunCC recognizes above declarations as different functions and
359        generates broken code for hbpcre." I have changed the declarations to use
360        USPTR.
362    16. GNU libtool is named differently on some systems. The autogen.sh script now
363        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
364        (FreeBSD).
366    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
367        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
368        comment: "Figure out how to create a longlong from a string: strtoll and
369        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
370        instance, but it only takes 2 args instead of 3!"
372    18. A subtle bug concerned with back references has been fixed by a change of
373        specification, with a corresponding code fix. A pattern such as
374        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
375        refers, was giving matches when it shouldn't. For example, xa=xaaa would
376        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
377        same bug. Such groups have to be quantified to be useful, or contained
378        inside another quantified group. (If there's no repetition, the reference
379        can never match.) The problem arises because, having left the group and
380        moved on to the rest of the pattern, a later failure that backtracks into
381        the group uses the captured value from the final iteration of the group
382        rather than the correct earlier one. I have fixed this in PCRE by forcing
383        any group that contains a reference to itself to be an atomic group; that
384        is, there cannot be any backtracking into it once it has completed. This is
385        similar to recursive and subroutine calls.
388  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
389  ----------------------  ----------------------

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