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revision 393 by ph10, Tue Mar 17 21:47:54 2009 UTC revision 492 by ph10, Tue Mar 2 11:26:55 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.9 xx-xxx-09  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    
13    Version 8.01 19-Jan-2010
14    ------------------------
15    
16    1.  If a pattern contained a conditional subpattern with only one branch (in
17        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
18        computed the wrong minimum data length (which is of course zero for such
19        subpatterns). This could cause incorrect "no match" results.
20    
21    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
22        the pattern is reset in the first branch, pcre_compile() failed with
23        "internal error: code overflow at offset...". This happened only when
24        the reset was to the original external option setting. (An optimization
25        abstracts leading options settings into an external setting, which was the
26        cause of this.)
27    
28    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
29        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
30        assertion pattern did not match (meaning that the assertion was true), it
31        was incorrectly treated as false if the SKIP had been reached during the
32        matching. This also applied to assertions used as conditions.
33    
34    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
35        assertion subpattern, including such a pattern used as a condition,
36        unpredictable results occurred, instead of the error return
37        PCRE_ERROR_DFA_UITEM.
38    
39    5.  The C++ GlobalReplace function was not working like Perl for the special
40        situation when an empty string is matched. It now does the fancy magic
41        stuff that is necessary.
42    
43    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
44        removed. (These were left over from very, very early versions of PCRE.)
45    
46    7.  Some cosmetic changes to the code to make life easier when compiling it
47        as part of something else:
48    
49        (a) Change DEBUG to PCRE_DEBUG.
50    
51        (b) In pcre_compile(), rename the member of the "branch_chain" structure
52            called "current" as "current_branch", to prevent a collision with the
53            Linux macro when compiled as a kernel module.
54    
55        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
56            prevent a collision with the Linux macro when compiled as a kernel
57            module.
58    
59    8.  In pcre_compile() there are some checks for integer overflows that used to
60        cast potentially large values to (double). This has been changed to that
61        when building, a check for int64_t is made, and if it is found, it is used
62        instead, thus avoiding the use of floating point arithmetic. (There is no
63        other use of FP in PCRE.) If int64_t is not found, the fallback is to
64        double.
65    
66    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
67        2005 (difference between two addresses compared to an unsigned value).
68    
69    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
70        custom one, because of the following reported problem in Windows:
71    
72          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
73              under Win32.
74          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
75              therefore missing the function definition.
76          - The compiler thus generates a "C" signature for the test function.
77          - The linker fails to find the "C" function.
78          - PCRE fails to configure if asked to do so against libbz2.
79    
80    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
81        messages were output:
82    
83          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
84          rerunning libtoolize, to keep the correct libtool macros in-tree.
85          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
86    
87        I have done both of these things.
88    
89    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
90        most of the time, it *can* run out if it is given a pattern that contains a
91        runaway infinite recursion. I updated the discussion in the pcrestack man
92        page.
93    
94    13. Now that we have gone to the x.xx style of version numbers, the minor
95        version may start with zero. Using 08 or 09 is a bad idea because users
96        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
97        interpreted as invalid octal numbers. I've updated the previous comment in
98        configure.ac, and also added a check that gives an error if 08 or 09 are
99        used.
100    
101    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
102        causing partial matching to fail when the end of the subject matched \W
103        in a UTF-8 pattern where \W was quantified with a minimum of 3.
104    
105    15. There were some discrepancies between the declarations in pcre_internal.h
106        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
107        their definitions. The declarations used "const uschar *" and the
108        definitions used USPTR. Even though USPTR is normally defined as "const
109        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
110        reported that: "This difference in casting confuses some C++ compilers, for
111        example, SunCC recognizes above declarations as different functions and
112        generates broken code for hbpcre." I have changed the declarations to use
113        USPTR.
114    
115    16. GNU libtool is named differently on some systems. The autogen.sh script now
116        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
117        (FreeBSD).
118    
119    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
120        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
121        comment: "Figure out how to create a longlong from a string: strtoll and
122        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
123        instance, but it only takes 2 args instead of 3!"
124    
125    18. A subtle bug concerned with back references has been fixed by a change of
126        specification, with a corresponding code fix. A pattern such as
127        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
128        refers, was giving matches when it shouldn't. For example, xa=xaaa would
129        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
130        same bug. Such groups have to be quantified to be useful, or contained
131        inside another quantified group. (If there's no repetition, the reference
132        can never match.) The problem arises because, having left the group and
133        moved on to the rest of the pattern, a later failure that backtracks into
134        the group uses the captured value from the final iteration of the group
135        rather than the correct earlier one. I have fixed this in PCRE by forcing
136        any group that contains a reference to itself to be an atomic group; that
137        is, there cannot be any backtracking into it once it has completed. This is
138        similar to recursive and subroutine calls.
139    
140    
141    Version 8.00 19-Oct-09
142    ----------------------
143    
144    1.  The table for translating pcre_compile() error codes into POSIX error codes
145        was out-of-date, and there was no check on the pcre_compile() error code
146        being within the table. This could lead to an OK return being given in
147        error.
148    
149    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
150        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
151        in a Windows environment.
152    
153    3.  The pcregrep --count option prints the count for each file even when it is
154        zero, as does GNU grep. However, pcregrep was also printing all files when
155        --files-with-matches was added. Now, when both options are given, it prints
156        counts only for those files that have at least one match. (GNU grep just
157        prints the file name in this circumstance, but including the count seems
158        more useful - otherwise, why use --count?) Also ensured that the
159        combination -clh just lists non-zero counts, with no names.
160    
161    4.  The long form of the pcregrep -F option was incorrectly implemented as
162        --fixed_strings instead of --fixed-strings. This is an incompatible change,
163        but it seems right to fix it, and I didn't think it was worth preserving
164        the old behaviour.
165    
166    5.  The command line items --regex=pattern and --regexp=pattern were not
167        recognized by pcregrep, which required --regex pattern or --regexp pattern
168        (with a space rather than an '='). The man page documented the '=' forms,
169        which are compatible with GNU grep; these now work.
170    
171    6.  No libpcreposix.pc file was created for pkg-config; there was just
172        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
173    
174    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
175        when UCP support is not needed, by modifying the Python script that
176        generates it from Unicode data files. This should not matter if the module
177        is correctly used as a library, but I received one complaint about 50K of
178        unwanted data. My guess is that the person linked everything into his
179        program rather than using a library. Anyway, it does no harm.
180    
181    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
182        was a minimum greater than 1 for a wide character in a possessive
183        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
184        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
185        character. Chaos in the form of incorrect output or a compiling loop could
186        result.
187    
188    9.  The restrictions on what a pattern can contain when partial matching is
189        requested for pcre_exec() have been removed. All patterns can now be
190        partially matched by this function. In addition, if there are at least two
191        slots in the offset vector, the offset of the earliest inspected character
192        for the match and the offset of the end of the subject are set in them when
193        PCRE_ERROR_PARTIAL is returned.
194    
195    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
196        synonymous with PCRE_PARTIAL, for backwards compatibility, and
197        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
198        and may be more useful for multi-segment matching.
199    
200    11. Partial matching with pcre_exec() is now more intuitive. A partial match
201        used to be given if ever the end of the subject was reached; now it is
202        given only if matching could not proceed because another character was
203        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
204        string "Z", which now yields "no match" instead of "partial match". In the
205        case of pcre_dfa_exec(), "no match" is given if every matching path for the
206        final character ended with (*FAIL).
207    
208    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
209        if the pattern had a "must contain" character that was already found in the
210        earlier partial match, unless partial matching was again requested. For
211        example, with the pattern /dog.(body)?/, the "must contain" character is
212        "g". If the first part-match was for the string "dog", restarting with
213        "sbody" failed. This bug has been fixed.
214    
215    13. The string returned by pcre_dfa_exec() after a partial match has been
216        changed so that it starts at the first inspected character rather than the
217        first character of the match. This makes a difference only if the pattern
218        starts with a lookbehind assertion or \b or \B (\K is not supported by
219        pcre_dfa_exec()). It's an incompatible change, but it makes the two
220        matching functions compatible, and I think it's the right thing to do.
221    
222    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
223        so that the demonstration program is easily available in environments where
224        PCRE has not been installed from source.
225    
226    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
227        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
228        library.
229    
230    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
231        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
232        is not the first non-POSIX option to be added. Clearly some people find
233        these options useful.
234    
235    17. If a caller to the POSIX matching function regexec() passes a non-zero
236        value for nmatch with a NULL value for pmatch, the value of
237        nmatch is forced to zero.
238    
239    18. RunGrepTest did not have a test for the availability of the -u option of
240        the diff command, as RunTest does. It now checks in the same way as
241        RunTest, and also checks for the -b option.
242    
243    19. If an odd number of negated classes containing just a single character
244        interposed, within parentheses, between a forward reference to a named
245        subpattern and the definition of the subpattern, compilation crashed with
246        an internal error, complaining that it could not find the referenced
247        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
248        [The bug was that it was starting one character too far in when skipping
249        over the character class, thus treating the ] as data rather than
250        terminating the class. This meant it could skip too much.]
251    
252    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
253        /g option in pcretest when the pattern contains \K, which makes it possible
254        to have an empty string match not at the start, even when the pattern is
255        anchored. Updated pcretest and pcredemo to use this option.
256    
257    21. If the maximum number of capturing subpatterns in a recursion was greater
258        than the maximum at the outer level, the higher number was returned, but
259        with unset values at the outer level. The correct (outer level) value is
260        now given.
261    
262    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
263        PCRE did not set those parentheses (unlike Perl). I have now found a way to
264        make it do so. The string so far is captured, making this feature
265        compatible with Perl.
266    
267    23. The tests have been re-organized, adding tests 11 and 12, to make it
268        possible to check the Perl 5.10 features against Perl 5.10.
269    
270    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
271        pattern matches a fixed length string. PCRE did not allow this; now it
272        does. Neither allows recursion.
273    
274    25. I finally figured out how to implement a request to provide the minimum
275        length of subject string that was needed in order to match a given pattern.
276        (It was back references and recursion that I had previously got hung up
277        on.) This code has now been added to pcre_study(); it finds a lower bound
278        to the length of subject needed. It is not necessarily the greatest lower
279        bound, but using it to avoid searching strings that are too short does give
280        some useful speed-ups. The value is available to calling programs via
281        pcre_fullinfo().
282    
283    26. While implementing 25, I discovered to my embarrassment that pcretest had
284        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
285        study optimizations had never been tested with that matching function.
286        Oops. What is worse, even when it was passed study data, there was a bug in
287        pcre_dfa_exec() that meant it never actually used it. Double oops. There
288        were also very few tests of studied patterns with pcre_dfa_exec().
289    
290    27. If (?| is used to create subpatterns with duplicate numbers, they are now
291        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
292        on the other side of the coin, they are no longer allowed to have different
293        names, because these cannot be distinguished in PCRE, and this has caused
294        confusion. (This is a difference from Perl.)
295    
296    28. When duplicate subpattern names are present (necessarily with different
297        numbers, as required by 27 above), and a test is made by name in a
298        conditional pattern, either for a subpattern having been matched, or for
299        recursion in such a pattern, all the associated numbered subpatterns are
300        tested, and the overall condition is true if the condition is true for any
301        one of them. This is the way Perl works, and is also more like the way
302        testing by number works.
303    
304    
305    Version 7.9 11-Apr-09
306  ---------------------  ---------------------
307    
308  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 318  Version 7.9 xx-xxx-09
318      but BOOL is not.      but BOOL is not.
319    
320  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
321      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
322    
323  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
324      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 42  Version 7.9 xx-xxx-09 Line 343  Version 7.9 xx-xxx-09
343      correctly handled. The rule now is that both the assertion and what follows      correctly handled. The rule now is that both the assertion and what follows
344      in the first alternative must satisfy the test.      in the first alternative must satisfy the test.
345    
346  9.  If auto-callout was enabled in a pattern with a conditional group, PCRE  9.  If auto-callout was enabled in a pattern with a conditional group whose
347      could crash during matching.      condition was an assertion, PCRE could crash during matching, both with
348        pcre_exec() and pcre_dfa_exec().
349    
350  10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was  10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
351      used for matching.      used for matching.
# Line 63  Version 7.9 xx-xxx-09 Line 365  Version 7.9 xx-xxx-09
365  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
366      from Martin Jerabek that uses macro names for all relevant character and      from Martin Jerabek that uses macro names for all relevant character and
367      string constants.      string constants.
368    
369  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
370      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
371      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
372      these, but not everybody uses configure.      these, but not everybody uses configure.
373    
374    19. A conditional group that had only one branch was not being correctly
375        recognized as an item that could match an empty string. This meant that an
376        enclosing group might also not be so recognized, causing infinite looping
377        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
378        with the subject "ab", where knowledge that the repeated group can match
379        nothing is needed in order to break the loop.
380    
381    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
382        exec(), but without supplying a callout function, matching went wrong.
383    
384    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
385        leak if the size of the offset vector was greater than 30. When the vector
386        is smaller, the saved offsets during recursion go onto a local stack
387        vector, but for larger vectors malloc() is used. It was failing to free
388        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
389        error, in fact).
390    
391    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
392        heapframe that is used only when UTF-8 support is enabled. This caused no
393        problem, but was untidy.
394    
395    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
396        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
397        included within another project.
398    
399    24. Steven Van Ingelgem's patches to add more options to the CMake support,
400        slightly modified by me:
401    
402          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
403              not building pcregrep.
404    
405          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
406              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
407    
408    25. Forward references, both numeric and by name, in patterns that made use of
409        duplicate group numbers, could behave incorrectly or give incorrect errors,
410        because when scanning forward to find the reference group, PCRE was not
411        taking into account the duplicate group numbers. A pattern such as
412        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
413    
414    26. Changed a few more instances of "const unsigned char *" to USPTR, making
415        the feature of a custom pointer more persuasive (as requested by a user).
416    
417    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
418        pcretest.c, inside #ifndefs, because it seems they are sometimes already
419        pre-defined.
420    
421    28. Added support for (*UTF8) at the start of a pattern.
422    
423    29. Arrange for flags added by the "release type" setting in CMake to be shown
424        in the configuration summary.
425    
426    
427  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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