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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.02 01-Mar-2010
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
8    
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
11    
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
14    
15    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
16        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
17    
18    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
19        quantifier applied to a forward-referencing subroutine call, could compile
20        incorrect code or give the error "internal error: previously-checked
21        referenced subpattern not found".
22    
23    6.  Both MS Visual Studio and Symbian OS have problems with initializing
24        variables to point to external functions. For these systems, therefore,
25        pcre_malloc etc. are now initialized to local functions that call the
26        relevant global functions.
27    
28    7.  There were two entries missing in the vectors called coptable and poptable
29        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
30        I've fixed the data, and added a kludgy way of testing at compile time that
31        the lengths are correct (equal to the number of opcodes).
32    
33    8.  Following on from 7, I added a similar kludge to check the length of the
34        eint vector in pcreposix.c.
35    
36    9.  Error texts for pcre_compile() are held as one long string to avoid too
37        much relocation at load time. To find a text, the string is searched,
38        counting zeros. There was no check for running off the end of the string,
39        which could happen if a new error number was added without updating the
40        string.
41    
42    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
43    
44    11. \K was not working if it appeared in an atomic group or in a group that
45        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
46        \K is "not well defined" if used in an assertion. PCRE now accepts it if
47        the assertion is positive, but not if it is negative.
48    
49    
50    Version 8.01 19-Jan-2010
51    ------------------------
52    
53    1.  If a pattern contained a conditional subpattern with only one branch (in
54        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
55        computed the wrong minimum data length (which is of course zero for such
56        subpatterns). This could cause incorrect "no match" results.
57    
58    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
59        the pattern is reset in the first branch, pcre_compile() failed with
60        "internal error: code overflow at offset...". This happened only when
61        the reset was to the original external option setting. (An optimization
62        abstracts leading options settings into an external setting, which was the
63        cause of this.)
64    
65    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
66        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
67        assertion pattern did not match (meaning that the assertion was true), it
68        was incorrectly treated as false if the SKIP had been reached during the
69        matching. This also applied to assertions used as conditions.
70    
71    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
72        assertion subpattern, including such a pattern used as a condition,
73        unpredictable results occurred, instead of the error return
74        PCRE_ERROR_DFA_UITEM.
75    
76    5.  The C++ GlobalReplace function was not working like Perl for the special
77        situation when an empty string is matched. It now does the fancy magic
78        stuff that is necessary.
79    
80    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
81        removed. (These were left over from very, very early versions of PCRE.)
82    
83    7.  Some cosmetic changes to the code to make life easier when compiling it
84        as part of something else:
85    
86        (a) Change DEBUG to PCRE_DEBUG.
87    
88        (b) In pcre_compile(), rename the member of the "branch_chain" structure
89            called "current" as "current_branch", to prevent a collision with the
90            Linux macro when compiled as a kernel module.
91    
92        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
93            prevent a collision with the Linux macro when compiled as a kernel
94            module.
95    
96    8.  In pcre_compile() there are some checks for integer overflows that used to
97        cast potentially large values to (double). This has been changed to that
98        when building, a check for int64_t is made, and if it is found, it is used
99        instead, thus avoiding the use of floating point arithmetic. (There is no
100        other use of FP in PCRE.) If int64_t is not found, the fallback is to
101        double.
102    
103    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
104        2005 (difference between two addresses compared to an unsigned value).
105    
106    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
107        custom one, because of the following reported problem in Windows:
108    
109          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
110              under Win32.
111          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
112              therefore missing the function definition.
113          - The compiler thus generates a "C" signature for the test function.
114          - The linker fails to find the "C" function.
115          - PCRE fails to configure if asked to do so against libbz2.
116    
117    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
118        messages were output:
119    
120          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
121          rerunning libtoolize, to keep the correct libtool macros in-tree.
122          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
123    
124        I have done both of these things.
125    
126    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
127        most of the time, it *can* run out if it is given a pattern that contains a
128        runaway infinite recursion. I updated the discussion in the pcrestack man
129        page.
130    
131    13. Now that we have gone to the x.xx style of version numbers, the minor
132        version may start with zero. Using 08 or 09 is a bad idea because users
133        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
134        interpreted as invalid octal numbers. I've updated the previous comment in
135        configure.ac, and also added a check that gives an error if 08 or 09 are
136        used.
137    
138    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
139        causing partial matching to fail when the end of the subject matched \W
140        in a UTF-8 pattern where \W was quantified with a minimum of 3.
141    
142    15. There were some discrepancies between the declarations in pcre_internal.h
143        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
144        their definitions. The declarations used "const uschar *" and the
145        definitions used USPTR. Even though USPTR is normally defined as "const
146        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
147        reported that: "This difference in casting confuses some C++ compilers, for
148        example, SunCC recognizes above declarations as different functions and
149        generates broken code for hbpcre." I have changed the declarations to use
150        USPTR.
151    
152    16. GNU libtool is named differently on some systems. The autogen.sh script now
153        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
154        (FreeBSD).
155    
156    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
157        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
158        comment: "Figure out how to create a longlong from a string: strtoll and
159        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
160        instance, but it only takes 2 args instead of 3!"
161    
162    18. A subtle bug concerned with back references has been fixed by a change of
163        specification, with a corresponding code fix. A pattern such as
164        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
165        refers, was giving matches when it shouldn't. For example, xa=xaaa would
166        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
167        same bug. Such groups have to be quantified to be useful, or contained
168        inside another quantified group. (If there's no repetition, the reference
169        can never match.) The problem arises because, having left the group and
170        moved on to the rest of the pattern, a later failure that backtracks into
171        the group uses the captured value from the final iteration of the group
172        rather than the correct earlier one. I have fixed this in PCRE by forcing
173        any group that contains a reference to itself to be an atomic group; that
174        is, there cannot be any backtracking into it once it has completed. This is
175        similar to recursive and subroutine calls.
176    
177    
178    Version 8.00 19-Oct-09
179    ----------------------
180    
181    1.  The table for translating pcre_compile() error codes into POSIX error codes
182        was out-of-date, and there was no check on the pcre_compile() error code
183        being within the table. This could lead to an OK return being given in
184        error.
185    
186    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
187        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
188        in a Windows environment.
189    
190    3.  The pcregrep --count option prints the count for each file even when it is
191        zero, as does GNU grep. However, pcregrep was also printing all files when
192        --files-with-matches was added. Now, when both options are given, it prints
193        counts only for those files that have at least one match. (GNU grep just
194        prints the file name in this circumstance, but including the count seems
195        more useful - otherwise, why use --count?) Also ensured that the
196        combination -clh just lists non-zero counts, with no names.
197    
198    4.  The long form of the pcregrep -F option was incorrectly implemented as
199        --fixed_strings instead of --fixed-strings. This is an incompatible change,
200        but it seems right to fix it, and I didn't think it was worth preserving
201        the old behaviour.
202    
203    5.  The command line items --regex=pattern and --regexp=pattern were not
204        recognized by pcregrep, which required --regex pattern or --regexp pattern
205        (with a space rather than an '='). The man page documented the '=' forms,
206        which are compatible with GNU grep; these now work.
207    
208    6.  No libpcreposix.pc file was created for pkg-config; there was just
209        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
210    
211    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
212        when UCP support is not needed, by modifying the Python script that
213        generates it from Unicode data files. This should not matter if the module
214        is correctly used as a library, but I received one complaint about 50K of
215        unwanted data. My guess is that the person linked everything into his
216        program rather than using a library. Anyway, it does no harm.
217    
218    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
219        was a minimum greater than 1 for a wide character in a possessive
220        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
221        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
222        character. Chaos in the form of incorrect output or a compiling loop could
223        result.
224    
225    9.  The restrictions on what a pattern can contain when partial matching is
226        requested for pcre_exec() have been removed. All patterns can now be
227        partially matched by this function. In addition, if there are at least two
228        slots in the offset vector, the offset of the earliest inspected character
229        for the match and the offset of the end of the subject are set in them when
230        PCRE_ERROR_PARTIAL is returned.
231    
232    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
233        synonymous with PCRE_PARTIAL, for backwards compatibility, and
234        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
235        and may be more useful for multi-segment matching.
236    
237    11. Partial matching with pcre_exec() is now more intuitive. A partial match
238        used to be given if ever the end of the subject was reached; now it is
239        given only if matching could not proceed because another character was
240        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
241        string "Z", which now yields "no match" instead of "partial match". In the
242        case of pcre_dfa_exec(), "no match" is given if every matching path for the
243        final character ended with (*FAIL).
244    
245    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
246        if the pattern had a "must contain" character that was already found in the
247        earlier partial match, unless partial matching was again requested. For
248        example, with the pattern /dog.(body)?/, the "must contain" character is
249        "g". If the first part-match was for the string "dog", restarting with
250        "sbody" failed. This bug has been fixed.
251    
252    13. The string returned by pcre_dfa_exec() after a partial match has been
253        changed so that it starts at the first inspected character rather than the
254        first character of the match. This makes a difference only if the pattern
255        starts with a lookbehind assertion or \b or \B (\K is not supported by
256        pcre_dfa_exec()). It's an incompatible change, but it makes the two
257        matching functions compatible, and I think it's the right thing to do.
258    
259    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
260        so that the demonstration program is easily available in environments where
261        PCRE has not been installed from source.
262    
263    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
264        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
265        library.
266    
267    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
268        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
269        is not the first non-POSIX option to be added. Clearly some people find
270        these options useful.
271    
272    17. If a caller to the POSIX matching function regexec() passes a non-zero
273        value for nmatch with a NULL value for pmatch, the value of
274        nmatch is forced to zero.
275    
276    18. RunGrepTest did not have a test for the availability of the -u option of
277        the diff command, as RunTest does. It now checks in the same way as
278        RunTest, and also checks for the -b option.
279    
280    19. If an odd number of negated classes containing just a single character
281        interposed, within parentheses, between a forward reference to a named
282        subpattern and the definition of the subpattern, compilation crashed with
283        an internal error, complaining that it could not find the referenced
284        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
285        [The bug was that it was starting one character too far in when skipping
286        over the character class, thus treating the ] as data rather than
287        terminating the class. This meant it could skip too much.]
288    
289    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
290        /g option in pcretest when the pattern contains \K, which makes it possible
291        to have an empty string match not at the start, even when the pattern is
292        anchored. Updated pcretest and pcredemo to use this option.
293    
294    21. If the maximum number of capturing subpatterns in a recursion was greater
295        than the maximum at the outer level, the higher number was returned, but
296        with unset values at the outer level. The correct (outer level) value is
297        now given.
298    
299    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
300        PCRE did not set those parentheses (unlike Perl). I have now found a way to
301        make it do so. The string so far is captured, making this feature
302        compatible with Perl.
303    
304    23. The tests have been re-organized, adding tests 11 and 12, to make it
305        possible to check the Perl 5.10 features against Perl 5.10.
306    
307    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
308        pattern matches a fixed length string. PCRE did not allow this; now it
309        does. Neither allows recursion.
310    
311    25. I finally figured out how to implement a request to provide the minimum
312        length of subject string that was needed in order to match a given pattern.
313        (It was back references and recursion that I had previously got hung up
314        on.) This code has now been added to pcre_study(); it finds a lower bound
315        to the length of subject needed. It is not necessarily the greatest lower
316        bound, but using it to avoid searching strings that are too short does give
317        some useful speed-ups. The value is available to calling programs via
318        pcre_fullinfo().
319    
320    26. While implementing 25, I discovered to my embarrassment that pcretest had
321        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
322        study optimizations had never been tested with that matching function.
323        Oops. What is worse, even when it was passed study data, there was a bug in
324        pcre_dfa_exec() that meant it never actually used it. Double oops. There
325        were also very few tests of studied patterns with pcre_dfa_exec().
326    
327    27. If (?| is used to create subpatterns with duplicate numbers, they are now
328        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
329        on the other side of the coin, they are no longer allowed to have different
330        names, because these cannot be distinguished in PCRE, and this has caused
331        confusion. (This is a difference from Perl.)
332    
333    28. When duplicate subpattern names are present (necessarily with different
334        numbers, as required by 27 above), and a test is made by name in a
335        conditional pattern, either for a subpattern having been matched, or for
336        recursion in such a pattern, all the associated numbered subpatterns are
337        tested, and the overall condition is true if the condition is true for any
338        one of them. This is the way Perl works, and is also more like the way
339        testing by number works.
340    
341    
342  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
343  ---------------------  ---------------------
344    
# Line 112  Version 7.9 11-Apr-09 Line 450  Version 7.9 11-Apr-09
450    
451  26. Changed a few more instances of "const unsigned char *" to USPTR, making  26. Changed a few more instances of "const unsigned char *" to USPTR, making
452      the feature of a custom pointer more persuasive (as requested by a user).      the feature of a custom pointer more persuasive (as requested by a user).
453    
454  27. Wrapped the definitions of fileno and isatty for Windows, which appear in  27. Wrapped the definitions of fileno and isatty for Windows, which appear in
455      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
456      pre-defined.      pre-defined.
457    
458  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
459    
460  29. Arrange for flags added by the "release type" setting in CMake to be shown  29. Arrange for flags added by the "release type" setting in CMake to be shown
461      in the configuration summary.      in the configuration summary.

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