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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.01 11-Dec-09  Version 8.12 11-Jan-2011
5  ----------------------  ------------------------
7    1.  Fixed some typos in the markup of the man pages, and wrote a script that
8        checks for such things as part of the documentation building process.
11    Version 8.11 10-Dec-2010
12    ------------------------
14    1.  (*THEN) was not working properly if there were untried alternatives prior
15        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
16        backtracked to try for "b" instead of moving to the next alternative branch
17        at the same level (in this case, to look for "c"). The Perl documentation
18        is clear that when (*THEN) is backtracked onto, it goes to the "next
19        alternative in the innermost enclosing group".
21    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
22        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
23        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
24        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
25        (*THEN).
27    3.  If \s appeared in a character class, it removed the VT character from
28        the class, even if it had been included by some previous item, for example
29        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
30        of \s, but is part of the POSIX "space" class.)
32    4.  A partial match never returns an empty string (because you can always
33        match an empty string at the end of the subject); however the checking for
34        an empty string was starting at the "start of match" point. This has been
35        changed to the "earliest inspected character" point, because the returned
36        data for a partial match starts at this character. This means that, for
37        example, /(?<=abc)def/ gives a partial match for the subject "abc"
38        (previously it gave "no match").
40    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
41        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
42        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
43        has an implication that the given string is incomplete (because a partial
44        match is preferred over a full match). For this reason, these items now
45        give a partial match in this situation. [Aside: previously, the one case
46        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
47        match rather than a full match, which was wrong by the old rules, but is
48        now correct.]
50    6.  There was a bug in the handling of #-introduced comments, recognized when
51        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
52        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
53        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
54        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
55        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
56        places in pcre_compile().
58    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
59        comments when looking ahead for named forward references to subpatterns,
60        the only newline sequence it recognized was NL. It now handles newlines
61        according to the set newline convention.
63    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
64        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
65        cater for a lack of strerror(). These oversights have been fixed.
67    9.  Added --match-limit and --recursion-limit to pcregrep.
69    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
71    11. When the -o option was used, pcregrep was setting a return code of 1, even
72        when matches were found, and --line-buffered was not being honoured.
74    12. Added an optional parentheses number to the -o and --only-matching options
75        of pcregrep.
77    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
78        can match an empty string. The code to do it in pcretest and pcredemo
79        needed fixing:
81        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
82            only one byte after an empty string match just before CRLF (this case
83            just got forgotten; "any" and "anycrlf" were OK).
85        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
86            mode when an empty string match preceded an ASCII character followed by
87            a non-ASCII character. (The code for advancing by one character rather
88            than one byte was nonsense.)
90        (c) The pcredemo.c sample program did not have any code at all to handle
91            the cases when CRLF is a valid newline sequence.
93    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
94        as a starting offset was within the subject string. There is now a new
95        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
96        negative or greater than the length of the string. In order to test this,
97        pcretest is extended to allow the setting of negative starting offsets.
99    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
100        starting offset points to the beginning of a UTF-8 character was
101        unnecessarily clumsy. I tidied it up.
103    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
104        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
106    17. Nobody had reported that the --include_dir option, which was added in
107        release 7.7 should have been called --include-dir (hyphen, not underscore)
108        for compatibility with GNU grep. I have changed it to --include-dir, but
109        left --include_dir as an undocumented synonym, and the same for
110        --exclude-dir, though that is not available in GNU grep, at least as of
111        release 2.5.4.
113    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
114        characters from a string of bytes) have been redefined so as not to use
115        loops, in order to improve performance in some environments. At the same
116        time, I abstracted some of the common code into auxiliary macros to save
117        repetition (this should not affect the compiled code).
119    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
120        compile-time error is now given if \c is not followed by an ASCII
121        character, that is, a byte less than 128. (In EBCDIC mode, the code is
122        different, and any byte value is allowed.)
124    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
125        START_OPTIMIZE option, which is now allowed at compile time - but just
126        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
127        to pcregrep and other applications that have no direct access to PCRE
128        options. The new /Y option in pcretest sets this option when calling
129        pcre_compile().
131    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
132        back references. Groups containing recursive back references were forced to
133        be atomic by that change, but in the case of named groups, the amount of
134        memory required was incorrectly computed, leading to "Failed: internal
135        error: code overflow". This has been fixed.
137    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
138        pcretest.c, to avoid build problems in some Borland environments.
141    Version 8.10 25-Jun-2010
142    ------------------------
144    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
145        THEN.
147    2.  (*ACCEPT) was not working when inside an atomic group.
149    3.  Inside a character class, \B is treated as a literal by default, but
150        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
151        causes the error). The code is unchanged, but I tidied the documentation.
153    4.  Inside a character class, PCRE always treated \R and \X as literals,
154        whereas Perl faults them if its -w option is set. I have changed PCRE so
155        that it faults them when PCRE_EXTRA is set.
157    5.  Added support for \N, which always matches any character other than
158        newline. (It is the same as "." when PCRE_DOTALL is not set.)
160    6.  When compiling pcregrep with newer versions of gcc which may have
161        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
162        declared with attribute warn_unused_result" were given. Just casting the
163        result to (void) does not stop the warnings; a more elaborate fudge is
164        needed. I've used a macro to implement this.
166    7.  Minor change to pcretest.c to avoid a compiler warning.
168    8.  Added four artifical Unicode properties to help with an option to make
169        \s etc use properties (see next item). The new properties are: Xan
170        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
172    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
173        use Unicode properties. (*UCP) at the start of a pattern can be used to set
174        this option. Modified pcretest to add /W to test this facility. Added
175        REG_UCP to make it available via the POSIX interface.
177    10. Added --line-buffered to pcregrep.
179    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
180        studied, and the match started with a letter with a code point greater than
181        127 whose first byte was different to the first byte of the other case of
182        the letter, the other case of this starting letter was not recognized
183        (#976).
185    12. If a pattern that was studied started with a repeated Unicode property
186        test, for example, \p{Nd}+, there was the theoretical possibility of
187        setting up an incorrect bitmap of starting bytes, but fortunately it could
188        not have actually happened in practice until change 8 above was made (it
189        added property types that matched character-matching opcodes).
191    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
192        possible starting bytes for non-anchored patterns.
194    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
195        \R, and also a number of cases that involve Unicode properties, both
196        explicit and implicit when PCRE_UCP is set.
198    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
199        input, it could crash or give wrong results if characters with values
200        greater than 0xc0 were present in the subject string. (Detail: it assumed
201        UTF-8 input when processing these items.)
203    16. Added a lot of (int) casts to avoid compiler warnings in systems where
204        size_t is 64-bit (#991).
206    17. Added a check for running out of memory when PCRE is compiled with
207        --disable-stack-for-recursion (#990).
209    18. If the last data line in a file for pcretest does not have a newline on
210        the end, a newline was missing in the output.
212    19. The default pcre_chartables.c file recognizes only ASCII characters (values
213        less than 128) in its various bitmaps. However, there is a facility for
214        generating tables according to the current locale when PCRE is compiled. It
215        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
216        characters, are recognized by isspace() and therefore were getting set in
217        these tables, and indeed these tables seem to approximate to ISO 8859. This
218        caused a problem in UTF-8 mode when pcre_study() was used to create a list
219        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
220        which of course cannot start UTF-8 characters. I have changed the code so
221        that only real ASCII characters (less than 128) and the correct starting
222        bytes for UTF-8 encodings are set for characters greater than 127 when in
223        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
224        altogether.)
226    20. Added the /T option to pcretest so as to be able to run tests with non-
227        standard character tables, thus making it possible to include the tests
228        used for 19 above in the standard set of tests.
230    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
231        reference to a subpattern the other side of a comment that contains an
232        opening parenthesis caused either an internal compiling error, or a
233        reference to the wrong subpattern.
236    Version 8.02 19-Mar-2010
237    ------------------------
239    1.  The Unicode data tables have been updated to Unicode 5.2.0.
241    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
242        configured.
244    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
245        original author of that file, following a query about its status.
247    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
248        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
250    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
251        quantifier applied to a forward-referencing subroutine call, could compile
252        incorrect code or give the error "internal error: previously-checked
253        referenced subpattern not found".
255    6.  Both MS Visual Studio and Symbian OS have problems with initializing
256        variables to point to external functions. For these systems, therefore,
257        pcre_malloc etc. are now initialized to local functions that call the
258        relevant global functions.
260    7.  There were two entries missing in the vectors called coptable and poptable
261        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
262        I've fixed the data, and added a kludgy way of testing at compile time that
263        the lengths are correct (equal to the number of opcodes).
265    8.  Following on from 7, I added a similar kludge to check the length of the
266        eint vector in pcreposix.c.
268    9.  Error texts for pcre_compile() are held as one long string to avoid too
269        much relocation at load time. To find a text, the string is searched,
270        counting zeros. There was no check for running off the end of the string,
271        which could happen if a new error number was added without updating the
272        string.
274    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
276    11. \K was not working if it appeared in an atomic group or in a group that
277        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
278        \K is "not well defined" if used in an assertion. PCRE now accepts it if
279        the assertion is positive, but not if it is negative.
281    12. Change 11 fortuitously reduced the size of the stack frame used in the
282        "match()" function of pcre_exec.c by one pointer. Forthcoming
283        implementation of support for (*MARK) will need an extra pointer on the
284        stack; I have reserved it now, so that the stack frame size does not
285        decrease.
287    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
288        item in branch that calls a recursion is a subroutine call - as in the
289        second branch in the above example - was incorrectly given the compile-
290        time error "recursive call could loop indefinitely" because pcre_compile()
291        was not correctly checking the subroutine for matching a non-empty string.
293    14. The checks for overrunning compiling workspace could trigger after an
294        overrun had occurred. This is a "should never occur" error, but it can be
295        triggered by pathological patterns such as hundreds of nested parentheses.
296        The checks now trigger 100 bytes before the end of the workspace.
298    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
301    Version 8.01 19-Jan-2010
302    ------------------------
304  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
305      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
306      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
307      subpatterns).      subpatterns). This could cause incorrect "no match" results.
309    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
310        the pattern is reset in the first branch, pcre_compile() failed with
311        "internal error: code overflow at offset...". This happened only when
312        the reset was to the original external option setting. (An optimization
313        abstracts leading options settings into an external setting, which was the
314        cause of this.)
316    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
317        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
318        assertion pattern did not match (meaning that the assertion was true), it
319        was incorrectly treated as false if the SKIP had been reached during the
320        matching. This also applied to assertions used as conditions.
322    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
323        assertion subpattern, including such a pattern used as a condition,
324        unpredictable results occurred, instead of the error return
327    5.  The C++ GlobalReplace function was not working like Perl for the special
328        situation when an empty string is matched. It now does the fancy magic
329        stuff that is necessary.
331    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
332        removed. (These were left over from very, very early versions of PCRE.)
334    7.  Some cosmetic changes to the code to make life easier when compiling it
335        as part of something else:
337        (a) Change DEBUG to PCRE_DEBUG.
339        (b) In pcre_compile(), rename the member of the "branch_chain" structure
340            called "current" as "current_branch", to prevent a collision with the
341            Linux macro when compiled as a kernel module.
343        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
344            prevent a collision with the Linux macro when compiled as a kernel
345            module.
347    8.  In pcre_compile() there are some checks for integer overflows that used to
348        cast potentially large values to (double). This has been changed to that
349        when building, a check for int64_t is made, and if it is found, it is used
350        instead, thus avoiding the use of floating point arithmetic. (There is no
351        other use of FP in PCRE.) If int64_t is not found, the fallback is to
352        double.
354    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
355        2005 (difference between two addresses compared to an unsigned value).
357    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
358        custom one, because of the following reported problem in Windows:
360          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
361              under Win32.
362          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
363              therefore missing the function definition.
364          - The compiler thus generates a "C" signature for the test function.
365          - The linker fails to find the "C" function.
366          - PCRE fails to configure if asked to do so against libbz2.
368    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
369        messages were output:
371          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
372          rerunning libtoolize, to keep the correct libtool macros in-tree.
373          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
375        I have done both of these things.
377    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
378        most of the time, it *can* run out if it is given a pattern that contains a
379        runaway infinite recursion. I updated the discussion in the pcrestack man
380        page.
382    13. Now that we have gone to the x.xx style of version numbers, the minor
383        version may start with zero. Using 08 or 09 is a bad idea because users
384        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
385        interpreted as invalid octal numbers. I've updated the previous comment in
386        configure.ac, and also added a check that gives an error if 08 or 09 are
387        used.
389    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
390        causing partial matching to fail when the end of the subject matched \W
391        in a UTF-8 pattern where \W was quantified with a minimum of 3.
393    15. There were some discrepancies between the declarations in pcre_internal.h
394        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
395        their definitions. The declarations used "const uschar *" and the
396        definitions used USPTR. Even though USPTR is normally defined as "const
397        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
398        reported that: "This difference in casting confuses some C++ compilers, for
399        example, SunCC recognizes above declarations as different functions and
400        generates broken code for hbpcre." I have changed the declarations to use
401        USPTR.
403    16. GNU libtool is named differently on some systems. The autogen.sh script now
404        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
405        (FreeBSD).
407    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
408        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
409        comment: "Figure out how to create a longlong from a string: strtoll and
410        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
411        instance, but it only takes 2 args instead of 3!"
413    18. A subtle bug concerned with back references has been fixed by a change of
414        specification, with a corresponding code fix. A pattern such as
415        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
416        refers, was giving matches when it shouldn't. For example, xa=xaaa would
417        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
418        same bug. Such groups have to be quantified to be useful, or contained
419        inside another quantified group. (If there's no repetition, the reference
420        can never match.) The problem arises because, having left the group and
421        moved on to the rest of the pattern, a later failure that backtracks into
422        the group uses the captured value from the final iteration of the group
423        rather than the correct earlier one. I have fixed this in PCRE by forcing
424        any group that contains a reference to itself to be an atomic group; that
425        is, there cannot be any backtracking into it once it has completed. This is
426        similar to recursive and subroutine calls.
429  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09

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