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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.10 03 May-2010
5    ------------------------
6    
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
9    
10    2.  (*ACCEPT) was not working when inside an atomic group.
11    
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.
15    
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.
19    
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.)
22    
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.
28    
29    7.  Minor change to pcretest.c to avoid a compiler warning.
30    
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).
34    
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.
39    
40    10. Added --line-buffered to pcregrep.
41    
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.
46    
47    12. pcreposix.c included pcre.h before including pcre_internal.h. This caused a
48        conflict in the definition of PCRE_EXP_DECL. I have removed the include of
49        pcre.h as pcre_internal.h includes pcre.h itself. (This may be a bit of
50        historical tidying that never got done.)
51    
52    13. If a pattern that was studied started with a repeated Unicode property
53        test, for example, \p{Nd}+, there was the theoretical possibility of
54        setting up an incorrect bitmap of starting bytes, but fortunately it could
55        not have actually happened in practice until change 8 above was made (it
56        added property types that matched character-matching opcodes).
57    
58    14. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
59        possible starting bytes for non-anchored patterns.
60    
61    15. The "auto-possessify" feature of pcre_compile() now recognizes \R.
62    
63    
64    
65    Version 8.02 19-Mar-2010
66    ------------------------
67    
68    1.  The Unicode data tables have been updated to Unicode 5.2.0.
69    
70    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
71        configured.
72    
73    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
74        original author of that file, following a query about its status.
75    
76    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
77        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
78    
79    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
80        quantifier applied to a forward-referencing subroutine call, could compile
81        incorrect code or give the error "internal error: previously-checked
82        referenced subpattern not found".
83    
84    6.  Both MS Visual Studio and Symbian OS have problems with initializing
85        variables to point to external functions. For these systems, therefore,
86        pcre_malloc etc. are now initialized to local functions that call the
87        relevant global functions.
88    
89    7.  There were two entries missing in the vectors called coptable and poptable
90        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
91        I've fixed the data, and added a kludgy way of testing at compile time that
92        the lengths are correct (equal to the number of opcodes).
93    
94    8.  Following on from 7, I added a similar kludge to check the length of the
95        eint vector in pcreposix.c.
96    
97    9.  Error texts for pcre_compile() are held as one long string to avoid too
98        much relocation at load time. To find a text, the string is searched,
99        counting zeros. There was no check for running off the end of the string,
100        which could happen if a new error number was added without updating the
101        string.
102    
103    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
104    
105    11. \K was not working if it appeared in an atomic group or in a group that
106        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
107        \K is "not well defined" if used in an assertion. PCRE now accepts it if
108        the assertion is positive, but not if it is negative.
109    
110    12. Change 11 fortuitously reduced the size of the stack frame used in the
111        "match()" function of pcre_exec.c by one pointer. Forthcoming
112        implementation of support for (*MARK) will need an extra pointer on the
113        stack; I have reserved it now, so that the stack frame size does not
114        decrease.
115    
116    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
117        item in branch that calls a recursion is a subroutine call - as in the
118        second branch in the above example - was incorrectly given the compile-
119        time error "recursive call could loop indefinitely" because pcre_compile()
120        was not correctly checking the subroutine for matching a non-empty string.
121    
122    14. The checks for overrunning compiling workspace could trigger after an
123        overrun had occurred. This is a "should never occur" error, but it can be
124        triggered by pathological patterns such as hundreds of nested parentheses.
125        The checks now trigger 100 bytes before the end of the workspace.
126    
127    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
128    
129    
130    Version 8.01 19-Jan-2010
131    ------------------------
132    
133    1.  If a pattern contained a conditional subpattern with only one branch (in
134        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
135        computed the wrong minimum data length (which is of course zero for such
136        subpatterns). This could cause incorrect "no match" results.
137    
138    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
139        the pattern is reset in the first branch, pcre_compile() failed with
140        "internal error: code overflow at offset...". This happened only when
141        the reset was to the original external option setting. (An optimization
142        abstracts leading options settings into an external setting, which was the
143        cause of this.)
144    
145    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
146        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
147        assertion pattern did not match (meaning that the assertion was true), it
148        was incorrectly treated as false if the SKIP had been reached during the
149        matching. This also applied to assertions used as conditions.
150    
151    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
152        assertion subpattern, including such a pattern used as a condition,
153        unpredictable results occurred, instead of the error return
154        PCRE_ERROR_DFA_UITEM.
155    
156    5.  The C++ GlobalReplace function was not working like Perl for the special
157        situation when an empty string is matched. It now does the fancy magic
158        stuff that is necessary.
159    
160    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
161        removed. (These were left over from very, very early versions of PCRE.)
162    
163    7.  Some cosmetic changes to the code to make life easier when compiling it
164        as part of something else:
165    
166        (a) Change DEBUG to PCRE_DEBUG.
167    
168        (b) In pcre_compile(), rename the member of the "branch_chain" structure
169            called "current" as "current_branch", to prevent a collision with the
170            Linux macro when compiled as a kernel module.
171    
172        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
173            prevent a collision with the Linux macro when compiled as a kernel
174            module.
175    
176    8.  In pcre_compile() there are some checks for integer overflows that used to
177        cast potentially large values to (double). This has been changed to that
178        when building, a check for int64_t is made, and if it is found, it is used
179        instead, thus avoiding the use of floating point arithmetic. (There is no
180        other use of FP in PCRE.) If int64_t is not found, the fallback is to
181        double.
182    
183    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
184        2005 (difference between two addresses compared to an unsigned value).
185    
186    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
187        custom one, because of the following reported problem in Windows:
188    
189          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
190              under Win32.
191          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
192              therefore missing the function definition.
193          - The compiler thus generates a "C" signature for the test function.
194          - The linker fails to find the "C" function.
195          - PCRE fails to configure if asked to do so against libbz2.
196    
197    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
198        messages were output:
199    
200          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
201          rerunning libtoolize, to keep the correct libtool macros in-tree.
202          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
203    
204        I have done both of these things.
205    
206    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
207        most of the time, it *can* run out if it is given a pattern that contains a
208        runaway infinite recursion. I updated the discussion in the pcrestack man
209        page.
210    
211    13. Now that we have gone to the x.xx style of version numbers, the minor
212        version may start with zero. Using 08 or 09 is a bad idea because users
213        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
214        interpreted as invalid octal numbers. I've updated the previous comment in
215        configure.ac, and also added a check that gives an error if 08 or 09 are
216        used.
217    
218    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
219        causing partial matching to fail when the end of the subject matched \W
220        in a UTF-8 pattern where \W was quantified with a minimum of 3.
221    
222    15. There were some discrepancies between the declarations in pcre_internal.h
223        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
224        their definitions. The declarations used "const uschar *" and the
225        definitions used USPTR. Even though USPTR is normally defined as "const
226        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
227        reported that: "This difference in casting confuses some C++ compilers, for
228        example, SunCC recognizes above declarations as different functions and
229        generates broken code for hbpcre." I have changed the declarations to use
230        USPTR.
231    
232    16. GNU libtool is named differently on some systems. The autogen.sh script now
233        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
234        (FreeBSD).
235    
236    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
237        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
238        comment: "Figure out how to create a longlong from a string: strtoll and
239        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
240        instance, but it only takes 2 args instead of 3!"
241    
242    18. A subtle bug concerned with back references has been fixed by a change of
243        specification, with a corresponding code fix. A pattern such as
244        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
245        refers, was giving matches when it shouldn't. For example, xa=xaaa would
246        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
247        same bug. Such groups have to be quantified to be useful, or contained
248        inside another quantified group. (If there's no repetition, the reference
249        can never match.) The problem arises because, having left the group and
250        moved on to the rest of the pattern, a later failure that backtracks into
251        the group uses the captured value from the final iteration of the group
252        rather than the correct earlier one. I have fixed this in PCRE by forcing
253        any group that contains a reference to itself to be an atomic group; that
254        is, there cannot be any backtracking into it once it has completed. This is
255        similar to recursive and subroutine calls.
256    
257    
258    Version 8.00 19-Oct-09
259  ----------------------  ----------------------
260    
261  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
262      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
263      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
264      error.      error.
265    
266  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,
267      "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
268      in a Windows environment.      in a Windows environment.
269    
270  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
271      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
272      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
273      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
274      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
275      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
276      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
277    
278  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
279      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
280      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
281      the old behaviour.      the old behaviour.
282    
283  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
284      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
285      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
286      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
287    
288  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
289      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
290    
291    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
292        when UCP support is not needed, by modifying the Python script that
293        generates it from Unicode data files. This should not matter if the module
294        is correctly used as a library, but I received one complaint about 50K of
295        unwanted data. My guess is that the person linked everything into his
296        program rather than using a library. Anyway, it does no harm.
297    
298    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
299        was a minimum greater than 1 for a wide character in a possessive
300        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
301        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
302        character. Chaos in the form of incorrect output or a compiling loop could
303        result.
304    
305    9.  The restrictions on what a pattern can contain when partial matching is
306        requested for pcre_exec() have been removed. All patterns can now be
307        partially matched by this function. In addition, if there are at least two
308        slots in the offset vector, the offset of the earliest inspected character
309        for the match and the offset of the end of the subject are set in them when
310        PCRE_ERROR_PARTIAL is returned.
311    
312    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
313        synonymous with PCRE_PARTIAL, for backwards compatibility, and
314        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
315        and may be more useful for multi-segment matching.
316    
317    11. Partial matching with pcre_exec() is now more intuitive. A partial match
318        used to be given if ever the end of the subject was reached; now it is
319        given only if matching could not proceed because another character was
320        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
321        string "Z", which now yields "no match" instead of "partial match". In the
322        case of pcre_dfa_exec(), "no match" is given if every matching path for the
323        final character ended with (*FAIL).
324    
325    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
326        if the pattern had a "must contain" character that was already found in the
327        earlier partial match, unless partial matching was again requested. For
328        example, with the pattern /dog.(body)?/, the "must contain" character is
329        "g". If the first part-match was for the string "dog", restarting with
330        "sbody" failed. This bug has been fixed.
331    
332    13. The string returned by pcre_dfa_exec() after a partial match has been
333        changed so that it starts at the first inspected character rather than the
334        first character of the match. This makes a difference only if the pattern
335        starts with a lookbehind assertion or \b or \B (\K is not supported by
336        pcre_dfa_exec()). It's an incompatible change, but it makes the two
337        matching functions compatible, and I think it's the right thing to do.
338    
339    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
340        so that the demonstration program is easily available in environments where
341        PCRE has not been installed from source.
342    
343    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
344        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
345        library.
346    
347    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
348        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
349        is not the first non-POSIX option to be added. Clearly some people find
350        these options useful.
351    
352    17. If a caller to the POSIX matching function regexec() passes a non-zero
353        value for nmatch with a NULL value for pmatch, the value of
354        nmatch is forced to zero.
355    
356    18. RunGrepTest did not have a test for the availability of the -u option of
357        the diff command, as RunTest does. It now checks in the same way as
358        RunTest, and also checks for the -b option.
359    
360    19. If an odd number of negated classes containing just a single character
361        interposed, within parentheses, between a forward reference to a named
362        subpattern and the definition of the subpattern, compilation crashed with
363        an internal error, complaining that it could not find the referenced
364        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
365        [The bug was that it was starting one character too far in when skipping
366        over the character class, thus treating the ] as data rather than
367        terminating the class. This meant it could skip too much.]
368    
369    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
370        /g option in pcretest when the pattern contains \K, which makes it possible
371        to have an empty string match not at the start, even when the pattern is
372        anchored. Updated pcretest and pcredemo to use this option.
373    
374    21. If the maximum number of capturing subpatterns in a recursion was greater
375        than the maximum at the outer level, the higher number was returned, but
376        with unset values at the outer level. The correct (outer level) value is
377        now given.
378    
379    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
380        PCRE did not set those parentheses (unlike Perl). I have now found a way to
381        make it do so. The string so far is captured, making this feature
382        compatible with Perl.
383    
384    23. The tests have been re-organized, adding tests 11 and 12, to make it
385        possible to check the Perl 5.10 features against Perl 5.10.
386    
387    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
388        pattern matches a fixed length string. PCRE did not allow this; now it
389        does. Neither allows recursion.
390    
391    25. I finally figured out how to implement a request to provide the minimum
392        length of subject string that was needed in order to match a given pattern.
393        (It was back references and recursion that I had previously got hung up
394        on.) This code has now been added to pcre_study(); it finds a lower bound
395        to the length of subject needed. It is not necessarily the greatest lower
396        bound, but using it to avoid searching strings that are too short does give
397        some useful speed-ups. The value is available to calling programs via
398        pcre_fullinfo().
399    
400    26. While implementing 25, I discovered to my embarrassment that pcretest had
401        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
402        study optimizations had never been tested with that matching function.
403        Oops. What is worse, even when it was passed study data, there was a bug in
404        pcre_dfa_exec() that meant it never actually used it. Double oops. There
405        were also very few tests of studied patterns with pcre_dfa_exec().
406    
407    27. If (?| is used to create subpatterns with duplicate numbers, they are now
408        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
409        on the other side of the coin, they are no longer allowed to have different
410        names, because these cannot be distinguished in PCRE, and this has caused
411        confusion. (This is a difference from Perl.)
412    
413    28. When duplicate subpattern names are present (necessarily with different
414        numbers, as required by 27 above), and a test is made by name in a
415        conditional pattern, either for a subpattern having been matched, or for
416        recursion in such a pattern, all the associated numbered subpatterns are
417        tested, and the overall condition is true if the condition is true for any
418        one of them. This is the way Perl works, and is also more like the way
419        testing by number works.
420    
421    
422  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
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