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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.8 25-Aug-08  Version 8.01 11-Dec-09
5    ----------------------
6    
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
11    
12    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
13        the pattern is reset in the first branch, pcre_compile() failed with
14        "internal error: code overflow at offset...". This happened only when
15        the reset was to the original external option setting. (An optimization
16        abstracts leading options settings into an external setting, which was the
17        cause of this.)
18    
19    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
20        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
21        assertion pattern did not match (meaning that the assertion was true), it
22        was incorrectly treated as false if the SKIP had been reached during the
23        matching. This also applied to assertions used as conditions.
24    
25    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
26        assertion subpattern, including such a pattern used as a condition,
27        unpredictable results occurred, instead of the error return
28        PCRE_ERROR_DFA_UITEM.
29    
30    5.  The C++ GlobalReplace function was not working like Perl for the special
31        situation when an empty string is matched. It now does the fancy magic
32        stuff that is necessary.
33    
34    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
35        removed. (These were left over from very, very early versions of PCRE.)
36    
37    7.  Some cosmetic changes to the code to make life easier when compiling it
38        as part of something else:
39    
40        (a) Change DEBUG to PCRE_DEBUG.
41    
42        (b) In pcre_compile(), rename the member of the "branch_chain" structure
43            called "current" as "current_branch", to prevent a collision with the
44            Linux macro when compiled as a kernel module.
45    
46        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
47            prevent a collision with the Linux macro when compiled as a kernel
48            module.
49    
50    8.  In pcre_compile() there are some checks for integer overflows that used to
51        cast potentially large values to (double). This has been changed to that
52        when building, a check for int64_t is made, and if it is found, it is used
53        instead, thus avoiding the use of floating point arithmetic. (There is no
54        other use of FP in PCRE.) If int64_t is not found, the fallback is to
55        double.
56    
57    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
58        2005 (difference between two addresses compared to an unsigned value).
59    
60    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
61        custom one, because of the following reported problem in Windows:
62    
63          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
64            under Win32.
65          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
66            therefore missing the function definition.
67          - The compiler thus generates a "C" signature for the test function.
68          - The linker fails to find the "C" function.
69          - PCRE fails to configure if asked to do so against libbz2.
70    
71    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
72        messages were output:
73    
74          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
75          rerunning libtoolize, to keep the correct libtool macros in-tree.
76          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
77    
78        I have done both of these things.
79    
80    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
81        most of the time, it *can* run out if it is given a pattern that contains a
82        runaway infinite recursion. I updated the discussion in the pcrestack man
83        page.
84    
85    13. Now that we have gone to the x.xx style of version numbers, the minor
86        version may start with zero. Using 08 or 09 is a bad idea because users
87        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
88        interpreted as invalid octal numbers. I've updated the previous comment in
89        configure.ac, and also added a check that gives an error if 08 or 09 are
90        used.
91    
92    
93    
94    Version 8.00 19-Oct-09
95    ----------------------
96    
97    1.  The table for translating pcre_compile() error codes into POSIX error codes
98        was out-of-date, and there was no check on the pcre_compile() error code
99        being within the table. This could lead to an OK return being given in
100        error.
101    
102    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
103        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
104        in a Windows environment.
105    
106    3.  The pcregrep --count option prints the count for each file even when it is
107        zero, as does GNU grep. However, pcregrep was also printing all files when
108        --files-with-matches was added. Now, when both options are given, it prints
109        counts only for those files that have at least one match. (GNU grep just
110        prints the file name in this circumstance, but including the count seems
111        more useful - otherwise, why use --count?) Also ensured that the
112        combination -clh just lists non-zero counts, with no names.
113    
114    4.  The long form of the pcregrep -F option was incorrectly implemented as
115        --fixed_strings instead of --fixed-strings. This is an incompatible change,
116        but it seems right to fix it, and I didn't think it was worth preserving
117        the old behaviour.
118    
119    5.  The command line items --regex=pattern and --regexp=pattern were not
120        recognized by pcregrep, which required --regex pattern or --regexp pattern
121        (with a space rather than an '='). The man page documented the '=' forms,
122        which are compatible with GNU grep; these now work.
123    
124    6.  No libpcreposix.pc file was created for pkg-config; there was just
125        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
126    
127    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
128        when UCP support is not needed, by modifying the Python script that
129        generates it from Unicode data files. This should not matter if the module
130        is correctly used as a library, but I received one complaint about 50K of
131        unwanted data. My guess is that the person linked everything into his
132        program rather than using a library. Anyway, it does no harm.
133    
134    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
135        was a minimum greater than 1 for a wide character in a possessive
136        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
137        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
138        character. Chaos in the form of incorrect output or a compiling loop could
139        result.
140    
141    9.  The restrictions on what a pattern can contain when partial matching is
142        requested for pcre_exec() have been removed. All patterns can now be
143        partially matched by this function. In addition, if there are at least two
144        slots in the offset vector, the offset of the earliest inspected character
145        for the match and the offset of the end of the subject are set in them when
146        PCRE_ERROR_PARTIAL is returned.
147    
148    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
149        synonymous with PCRE_PARTIAL, for backwards compatibility, and
150        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
151        and may be more useful for multi-segment matching.
152    
153    11. Partial matching with pcre_exec() is now more intuitive. A partial match
154        used to be given if ever the end of the subject was reached; now it is
155        given only if matching could not proceed because another character was
156        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
157        string "Z", which now yields "no match" instead of "partial match". In the
158        case of pcre_dfa_exec(), "no match" is given if every matching path for the
159        final character ended with (*FAIL).
160    
161    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
162        if the pattern had a "must contain" character that was already found in the
163        earlier partial match, unless partial matching was again requested. For
164        example, with the pattern /dog.(body)?/, the "must contain" character is
165        "g". If the first part-match was for the string "dog", restarting with
166        "sbody" failed. This bug has been fixed.
167    
168    13. The string returned by pcre_dfa_exec() after a partial match has been
169        changed so that it starts at the first inspected character rather than the
170        first character of the match. This makes a difference only if the pattern
171        starts with a lookbehind assertion or \b or \B (\K is not supported by
172        pcre_dfa_exec()). It's an incompatible change, but it makes the two
173        matching functions compatible, and I think it's the right thing to do.
174    
175    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
176        so that the demonstration program is easily available in environments where
177        PCRE has not been installed from source.
178    
179    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
180        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
181        library.
182    
183    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
184        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
185        is not the first non-POSIX option to be added. Clearly some people find
186        these options useful.
187    
188    17. If a caller to the POSIX matching function regexec() passes a non-zero
189        value for nmatch with a NULL value for pmatch, the value of
190        nmatch is forced to zero.
191    
192    18. RunGrepTest did not have a test for the availability of the -u option of
193        the diff command, as RunTest does. It now checks in the same way as
194        RunTest, and also checks for the -b option.
195    
196    19. If an odd number of negated classes containing just a single character
197        interposed, within parentheses, between a forward reference to a named
198        subpattern and the definition of the subpattern, compilation crashed with
199        an internal error, complaining that it could not find the referenced
200        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
201        [The bug was that it was starting one character too far in when skipping
202        over the character class, thus treating the ] as data rather than
203        terminating the class. This meant it could skip too much.]
204    
205    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
206        /g option in pcretest when the pattern contains \K, which makes it possible
207        to have an empty string match not at the start, even when the pattern is
208        anchored. Updated pcretest and pcredemo to use this option.
209    
210    21. If the maximum number of capturing subpatterns in a recursion was greater
211        than the maximum at the outer level, the higher number was returned, but
212        with unset values at the outer level. The correct (outer level) value is
213        now given.
214    
215    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
216        PCRE did not set those parentheses (unlike Perl). I have now found a way to
217        make it do so. The string so far is captured, making this feature
218        compatible with Perl.
219    
220    23. The tests have been re-organized, adding tests 11 and 12, to make it
221        possible to check the Perl 5.10 features against Perl 5.10.
222    
223    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
224        pattern matches a fixed length string. PCRE did not allow this; now it
225        does. Neither allows recursion.
226    
227    25. I finally figured out how to implement a request to provide the minimum
228        length of subject string that was needed in order to match a given pattern.
229        (It was back references and recursion that I had previously got hung up
230        on.) This code has now been added to pcre_study(); it finds a lower bound
231        to the length of subject needed. It is not necessarily the greatest lower
232        bound, but using it to avoid searching strings that are too short does give
233        some useful speed-ups. The value is available to calling programs via
234        pcre_fullinfo().
235    
236    26. While implementing 25, I discovered to my embarrassment that pcretest had
237        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
238        study optimizations had never been tested with that matching function.
239        Oops. What is worse, even when it was passed study data, there was a bug in
240        pcre_dfa_exec() that meant it never actually used it. Double oops. There
241        were also very few tests of studied patterns with pcre_dfa_exec().
242    
243    27. If (?| is used to create subpatterns with duplicate numbers, they are now
244        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
245        on the other side of the coin, they are no longer allowed to have different
246        names, because these cannot be distinguished in PCRE, and this has caused
247        confusion. (This is a difference from Perl.)
248    
249    28. When duplicate subpattern names are present (necessarily with different
250        numbers, as required by 27 above), and a test is made by name in a
251        conditional pattern, either for a subpattern having been matched, or for
252        recursion in such a pattern, all the associated numbered subpatterns are
253        tested, and the overall condition is true if the condition is true for any
254        one of them. This is the way Perl works, and is also more like the way
255        testing by number works.
256    
257    
258    Version 7.9 11-Apr-09
259    ---------------------
260    
261    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
262        (pcretest), all targets were linked against these libraries. This included
263        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
264        libraries. This caused unwanted dependencies to be created. This problem
265        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
266        pcretest is linked with readline.
267    
268    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
269        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
270        moved outside it again, because FALSE and TRUE are already defined in AIX,
271        but BOOL is not.
272    
273    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
274        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
275    
276    4.  The pcregrep documentation said spaces were inserted as well as colons (or
277        hyphens) following file names and line numbers when outputting matching
278        lines. This is not true; no spaces are inserted. I have also clarified the
279        wording for the --colour (or --color) option.
280    
281    5.  In pcregrep, when --colour was used with -o, the list of matching strings
282        was not coloured; this is different to GNU grep, so I have changed it to be
283        the same.
284    
285    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
286        each matching line was coloured. Now it goes on to look for further matches
287        of any of the test patterns, which is the same behaviour as GNU grep.
288    
289    7.  A pattern that could match an empty string could cause pcregrep to loop; it
290        doesn't make sense to accept an empty string match in pcregrep, so I have
291        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
292        seems to be how GNU grep behaves.
293    
294    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
295        start or after a newline", because the conditional assertion was not being
296        correctly handled. The rule now is that both the assertion and what follows
297        in the first alternative must satisfy the test.
298    
299    9.  If auto-callout was enabled in a pattern with a conditional group whose
300        condition was an assertion, PCRE could crash during matching, both with
301        pcre_exec() and pcre_dfa_exec().
302    
303    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
304        used for matching.
305    
306    11. Unicode property support in character classes was not working for
307        characters (bytes) greater than 127 when not in UTF-8 mode.
308    
309    12. Added the -M command line option to pcretest.
310    
311    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
312    
313    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
314    
315    16. Added comments and documentation about mis-use of no_arg in the C++
316        wrapper.
317    
318    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
319        from Martin Jerabek that uses macro names for all relevant character and
320        string constants.
321    
322    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
323        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
324        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
325        these, but not everybody uses configure.
326    
327    19. A conditional group that had only one branch was not being correctly
328        recognized as an item that could match an empty string. This meant that an
329        enclosing group might also not be so recognized, causing infinite looping
330        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
331        with the subject "ab", where knowledge that the repeated group can match
332        nothing is needed in order to break the loop.
333    
334    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
335        exec(), but without supplying a callout function, matching went wrong.
336    
337    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
338        leak if the size of the offset vector was greater than 30. When the vector
339        is smaller, the saved offsets during recursion go onto a local stack
340        vector, but for larger vectors malloc() is used. It was failing to free
341        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
342        error, in fact).
343    
344    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
345        heapframe that is used only when UTF-8 support is enabled. This caused no
346        problem, but was untidy.
347    
348    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
349        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
350        included within another project.
351    
352    24. Steven Van Ingelgem's patches to add more options to the CMake support,
353        slightly modified by me:
354    
355          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
356              not building pcregrep.
357    
358          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
359              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
360    
361    25. Forward references, both numeric and by name, in patterns that made use of
362        duplicate group numbers, could behave incorrectly or give incorrect errors,
363        because when scanning forward to find the reference group, PCRE was not
364        taking into account the duplicate group numbers. A pattern such as
365        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
366    
367    26. Changed a few more instances of "const unsigned char *" to USPTR, making
368        the feature of a custom pointer more persuasive (as requested by a user).
369    
370    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
371        pcretest.c, inside #ifndefs, because it seems they are sometimes already
372        pre-defined.
373    
374    28. Added support for (*UTF8) at the start of a pattern.
375    
376    29. Arrange for flags added by the "release type" setting in CMake to be shown
377        in the configuration summary.
378    
379    
380    Version 7.8 05-Sep-08
381  ---------------------  ---------------------
382    
383  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
# Line 73  Version 7.8 25-Aug-08 Line 449  Version 7.8 25-Aug-08
449    
450  18. Tidied a few places to stop certain compilers from issuing warnings.  18. Tidied a few places to stop certain compilers from issuing warnings.
451    
452    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
453        supplied by Stefan Weber. I made a further small update for 7.8 because
454        there is a change of source arrangements: the pcre_searchfuncs.c module is
455        replaced by pcre_ucd.c.
456    
457    
458  Version 7.7 07-May-08  Version 7.7 07-May-08
459  ---------------------  ---------------------

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