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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.00 ??-???-??  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.)
26    Version 8.10 25-Jun-2010
27    ------------------------
29    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
30        THEN.
32    2.  (*ACCEPT) was not working when inside an atomic group.
34    3.  Inside a character class, \B is treated as a literal by default, but
35        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
36        causes the error). The code is unchanged, but I tidied the documentation.
38    4.  Inside a character class, PCRE always treated \R and \X as literals,
39        whereas Perl faults them if its -w option is set. I have changed PCRE so
40        that it faults them when PCRE_EXTRA is set.
42    5.  Added support for \N, which always matches any character other than
43        newline. (It is the same as "." when PCRE_DOTALL is not set.)
45    6.  When compiling pcregrep with newer versions of gcc which may have
46        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
47        declared with attribute warn_unused_result" were given. Just casting the
48        result to (void) does not stop the warnings; a more elaborate fudge is
49        needed. I've used a macro to implement this.
51    7.  Minor change to pcretest.c to avoid a compiler warning.
53    8.  Added four artifical Unicode properties to help with an option to make
54        \s etc use properties (see next item). The new properties are: Xan
55        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
57    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
58        use Unicode properties. (*UCP) at the start of a pattern can be used to set
59        this option. Modified pcretest to add /W to test this facility. Added
60        REG_UCP to make it available via the POSIX interface.
62    10. Added --line-buffered to pcregrep.
64    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
65        studied, and the match started with a letter with a code point greater than
66        127 whose first byte was different to the first byte of the other case of
67        the letter, the other case of this starting letter was not recognized
68        (#976).
70    12. If a pattern that was studied started with a repeated Unicode property
71        test, for example, \p{Nd}+, there was the theoretical possibility of
72        setting up an incorrect bitmap of starting bytes, but fortunately it could
73        not have actually happened in practice until change 8 above was made (it
74        added property types that matched character-matching opcodes).
76    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
77        possible starting bytes for non-anchored patterns.
79    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
80        \R, and also a number of cases that involve Unicode properties, both
81        explicit and implicit when PCRE_UCP is set.
83    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
84        input, it could crash or give wrong results if characters with values
85        greater than 0xc0 were present in the subject string. (Detail: it assumed
86        UTF-8 input when processing these items.)
88    16. Added a lot of (int) casts to avoid compiler warnings in systems where
89        size_t is 64-bit (#991).
91    17. Added a check for running out of memory when PCRE is compiled with
92        --disable-stack-for-recursion (#990).
94    18. If the last data line in a file for pcretest does not have a newline on
95        the end, a newline was missing in the output.
97    19. The default pcre_chartables.c file recognizes only ASCII characters (values
98        less than 128) in its various bitmaps. However, there is a facility for
99        generating tables according to the current locale when PCRE is compiled. It
100        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
101        characters, are recognized by isspace() and therefore were getting set in
102        these tables, and indeed these tables seem to approximate to ISO 8859. This
103        caused a problem in UTF-8 mode when pcre_study() was used to create a list
104        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
105        which of course cannot start UTF-8 characters. I have changed the code so
106        that only real ASCII characters (less than 128) and the correct starting
107        bytes for UTF-8 encodings are set for characters greater than 127 when in
108        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
109        altogether.)
111    20. Added the /T option to pcretest so as to be able to run tests with non-
112        standard character tables, thus making it possible to include the tests
113        used for 19 above in the standard set of tests.
115    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
116        reference to a subpattern the other side of a comment that contains an
117        opening parenthesis caused either an internal compiling error, or a
118        reference to the wrong subpattern.
121    Version 8.02 19-Mar-2010
122    ------------------------
124    1.  The Unicode data tables have been updated to Unicode 5.2.0.
126    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
127        configured.
129    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
130        original author of that file, following a query about its status.
132    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
133        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
135    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
136        quantifier applied to a forward-referencing subroutine call, could compile
137        incorrect code or give the error "internal error: previously-checked
138        referenced subpattern not found".
140    6.  Both MS Visual Studio and Symbian OS have problems with initializing
141        variables to point to external functions. For these systems, therefore,
142        pcre_malloc etc. are now initialized to local functions that call the
143        relevant global functions.
145    7.  There were two entries missing in the vectors called coptable and poptable
146        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
147        I've fixed the data, and added a kludgy way of testing at compile time that
148        the lengths are correct (equal to the number of opcodes).
150    8.  Following on from 7, I added a similar kludge to check the length of the
151        eint vector in pcreposix.c.
153    9.  Error texts for pcre_compile() are held as one long string to avoid too
154        much relocation at load time. To find a text, the string is searched,
155        counting zeros. There was no check for running off the end of the string,
156        which could happen if a new error number was added without updating the
157        string.
159    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
161    11. \K was not working if it appeared in an atomic group or in a group that
162        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
163        \K is "not well defined" if used in an assertion. PCRE now accepts it if
164        the assertion is positive, but not if it is negative.
166    12. Change 11 fortuitously reduced the size of the stack frame used in the
167        "match()" function of pcre_exec.c by one pointer. Forthcoming
168        implementation of support for (*MARK) will need an extra pointer on the
169        stack; I have reserved it now, so that the stack frame size does not
170        decrease.
172    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
173        item in branch that calls a recursion is a subroutine call - as in the
174        second branch in the above example - was incorrectly given the compile-
175        time error "recursive call could loop indefinitely" because pcre_compile()
176        was not correctly checking the subroutine for matching a non-empty string.
178    14. The checks for overrunning compiling workspace could trigger after an
179        overrun had occurred. This is a "should never occur" error, but it can be
180        triggered by pathological patterns such as hundreds of nested parentheses.
181        The checks now trigger 100 bytes before the end of the workspace.
183    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
186    Version 8.01 19-Jan-2010
187    ------------------------
189    1.  If a pattern contained a conditional subpattern with only one branch (in
190        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
191        computed the wrong minimum data length (which is of course zero for such
192        subpatterns). This could cause incorrect "no match" results.
194    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
195        the pattern is reset in the first branch, pcre_compile() failed with
196        "internal error: code overflow at offset...". This happened only when
197        the reset was to the original external option setting. (An optimization
198        abstracts leading options settings into an external setting, which was the
199        cause of this.)
201    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
202        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
203        assertion pattern did not match (meaning that the assertion was true), it
204        was incorrectly treated as false if the SKIP had been reached during the
205        matching. This also applied to assertions used as conditions.
207    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
208        assertion subpattern, including such a pattern used as a condition,
209        unpredictable results occurred, instead of the error return
212    5.  The C++ GlobalReplace function was not working like Perl for the special
213        situation when an empty string is matched. It now does the fancy magic
214        stuff that is necessary.
216    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
217        removed. (These were left over from very, very early versions of PCRE.)
219    7.  Some cosmetic changes to the code to make life easier when compiling it
220        as part of something else:
222        (a) Change DEBUG to PCRE_DEBUG.
224        (b) In pcre_compile(), rename the member of the "branch_chain" structure
225            called "current" as "current_branch", to prevent a collision with the
226            Linux macro when compiled as a kernel module.
228        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
229            prevent a collision with the Linux macro when compiled as a kernel
230            module.
232    8.  In pcre_compile() there are some checks for integer overflows that used to
233        cast potentially large values to (double). This has been changed to that
234        when building, a check for int64_t is made, and if it is found, it is used
235        instead, thus avoiding the use of floating point arithmetic. (There is no
236        other use of FP in PCRE.) If int64_t is not found, the fallback is to
237        double.
239    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
240        2005 (difference between two addresses compared to an unsigned value).
242    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
243        custom one, because of the following reported problem in Windows:
245          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
246              under Win32.
247          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
248              therefore missing the function definition.
249          - The compiler thus generates a "C" signature for the test function.
250          - The linker fails to find the "C" function.
251          - PCRE fails to configure if asked to do so against libbz2.
253    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
254        messages were output:
256          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
257          rerunning libtoolize, to keep the correct libtool macros in-tree.
258          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
260        I have done both of these things.
262    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
263        most of the time, it *can* run out if it is given a pattern that contains a
264        runaway infinite recursion. I updated the discussion in the pcrestack man
265        page.
267    13. Now that we have gone to the x.xx style of version numbers, the minor
268        version may start with zero. Using 08 or 09 is a bad idea because users
269        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
270        interpreted as invalid octal numbers. I've updated the previous comment in
271        configure.ac, and also added a check that gives an error if 08 or 09 are
272        used.
274    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
275        causing partial matching to fail when the end of the subject matched \W
276        in a UTF-8 pattern where \W was quantified with a minimum of 3.
278    15. There were some discrepancies between the declarations in pcre_internal.h
279        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
280        their definitions. The declarations used "const uschar *" and the
281        definitions used USPTR. Even though USPTR is normally defined as "const
282        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
283        reported that: "This difference in casting confuses some C++ compilers, for
284        example, SunCC recognizes above declarations as different functions and
285        generates broken code for hbpcre." I have changed the declarations to use
286        USPTR.
288    16. GNU libtool is named differently on some systems. The autogen.sh script now
289        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
290        (FreeBSD).
292    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
293        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
294        comment: "Figure out how to create a longlong from a string: strtoll and
295        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
296        instance, but it only takes 2 args instead of 3!"
298    18. A subtle bug concerned with back references has been fixed by a change of
299        specification, with a corresponding code fix. A pattern such as
300        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
301        refers, was giving matches when it shouldn't. For example, xa=xaaa would
302        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
303        same bug. Such groups have to be quantified to be useful, or contained
304        inside another quantified group. (If there's no repetition, the reference
305        can never match.) The problem arises because, having left the group and
306        moved on to the rest of the pattern, a later failure that backtracks into
307        the group uses the captured value from the final iteration of the group
308        rather than the correct earlier one. I have fixed this in PCRE by forcing
309        any group that contains a reference to itself to be an atomic group; that
310        is, there cannot be any backtracking into it once it has completed. This is
311        similar to recursive and subroutine calls.
314    Version 8.00 19-Oct-09
315  ----------------------  ----------------------
317  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
318      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
319      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
320      error.      error.
322  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
323      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
324      in a Windows environment.      in a Windows environment.
326    3.  The pcregrep --count option prints the count for each file even when it is
327        zero, as does GNU grep. However, pcregrep was also printing all files when
328        --files-with-matches was added. Now, when both options are given, it prints
329        counts only for those files that have at least one match. (GNU grep just
330        prints the file name in this circumstance, but including the count seems
331        more useful - otherwise, why use --count?) Also ensured that the
332        combination -clh just lists non-zero counts, with no names.
334    4.  The long form of the pcregrep -F option was incorrectly implemented as
335        --fixed_strings instead of --fixed-strings. This is an incompatible change,
336        but it seems right to fix it, and I didn't think it was worth preserving
337        the old behaviour.
339    5.  The command line items --regex=pattern and --regexp=pattern were not
340        recognized by pcregrep, which required --regex pattern or --regexp pattern
341        (with a space rather than an '='). The man page documented the '=' forms,
342        which are compatible with GNU grep; these now work.
344    6.  No libpcreposix.pc file was created for pkg-config; there was just
345        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
347    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
348        when UCP support is not needed, by modifying the Python script that
349        generates it from Unicode data files. This should not matter if the module
350        is correctly used as a library, but I received one complaint about 50K of
351        unwanted data. My guess is that the person linked everything into his
352        program rather than using a library. Anyway, it does no harm.
354    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
355        was a minimum greater than 1 for a wide character in a possessive
356        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
357        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
358        character. Chaos in the form of incorrect output or a compiling loop could
359        result.
361    9.  The restrictions on what a pattern can contain when partial matching is
362        requested for pcre_exec() have been removed. All patterns can now be
363        partially matched by this function. In addition, if there are at least two
364        slots in the offset vector, the offset of the earliest inspected character
365        for the match and the offset of the end of the subject are set in them when
366        PCRE_ERROR_PARTIAL is returned.
368    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
369        synonymous with PCRE_PARTIAL, for backwards compatibility, and
370        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
371        and may be more useful for multi-segment matching.
373    11. Partial matching with pcre_exec() is now more intuitive. A partial match
374        used to be given if ever the end of the subject was reached; now it is
375        given only if matching could not proceed because another character was
376        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
377        string "Z", which now yields "no match" instead of "partial match". In the
378        case of pcre_dfa_exec(), "no match" is given if every matching path for the
379        final character ended with (*FAIL).
381    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
382        if the pattern had a "must contain" character that was already found in the
383        earlier partial match, unless partial matching was again requested. For
384        example, with the pattern /dog.(body)?/, the "must contain" character is
385        "g". If the first part-match was for the string "dog", restarting with
386        "sbody" failed. This bug has been fixed.
388    13. The string returned by pcre_dfa_exec() after a partial match has been
389        changed so that it starts at the first inspected character rather than the
390        first character of the match. This makes a difference only if the pattern
391        starts with a lookbehind assertion or \b or \B (\K is not supported by
392        pcre_dfa_exec()). It's an incompatible change, but it makes the two
393        matching functions compatible, and I think it's the right thing to do.
395    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
396        so that the demonstration program is easily available in environments where
397        PCRE has not been installed from source.
399    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
400        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
401        library.
403    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
404        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
405        is not the first non-POSIX option to be added. Clearly some people find
406        these options useful.
408    17. If a caller to the POSIX matching function regexec() passes a non-zero
409        value for nmatch with a NULL value for pmatch, the value of
410        nmatch is forced to zero.
412    18. RunGrepTest did not have a test for the availability of the -u option of
413        the diff command, as RunTest does. It now checks in the same way as
414        RunTest, and also checks for the -b option.
416    19. If an odd number of negated classes containing just a single character
417        interposed, within parentheses, between a forward reference to a named
418        subpattern and the definition of the subpattern, compilation crashed with
419        an internal error, complaining that it could not find the referenced
420        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
421        [The bug was that it was starting one character too far in when skipping
422        over the character class, thus treating the ] as data rather than
423        terminating the class. This meant it could skip too much.]
425    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
426        /g option in pcretest when the pattern contains \K, which makes it possible
427        to have an empty string match not at the start, even when the pattern is
428        anchored. Updated pcretest and pcredemo to use this option.
430    21. If the maximum number of capturing subpatterns in a recursion was greater
431        than the maximum at the outer level, the higher number was returned, but
432        with unset values at the outer level. The correct (outer level) value is
433        now given.
435    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
436        PCRE did not set those parentheses (unlike Perl). I have now found a way to
437        make it do so. The string so far is captured, making this feature
438        compatible with Perl.
440    23. The tests have been re-organized, adding tests 11 and 12, to make it
441        possible to check the Perl 5.10 features against Perl 5.10.
443    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
444        pattern matches a fixed length string. PCRE did not allow this; now it
445        does. Neither allows recursion.
447    25. I finally figured out how to implement a request to provide the minimum
448        length of subject string that was needed in order to match a given pattern.
449        (It was back references and recursion that I had previously got hung up
450        on.) This code has now been added to pcre_study(); it finds a lower bound
451        to the length of subject needed. It is not necessarily the greatest lower
452        bound, but using it to avoid searching strings that are too short does give
453        some useful speed-ups. The value is available to calling programs via
454        pcre_fullinfo().
456    26. While implementing 25, I discovered to my embarrassment that pcretest had
457        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
458        study optimizations had never been tested with that matching function.
459        Oops. What is worse, even when it was passed study data, there was a bug in
460        pcre_dfa_exec() that meant it never actually used it. Double oops. There
461        were also very few tests of studied patterns with pcre_dfa_exec().
463    27. If (?| is used to create subpatterns with duplicate numbers, they are now
464        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
465        on the other side of the coin, they are no longer allowed to have different
466        names, because these cannot be distinguished in PCRE, and this has caused
467        confusion. (This is a difference from Perl.)
469    28. When duplicate subpattern names are present (necessarily with different
470        numbers, as required by 27 above), and a test is made by name in a
471        conditional pattern, either for a subpattern having been matched, or for
472        recursion in such a pattern, all the associated numbered subpatterns are
473        tested, and the overall condition is true if the condition is true for any
474        one of them. This is the way Perl works, and is also more like the way
475        testing by number works.
478  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09

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