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revision 432 by ph10, Wed Sep 2 16:02:56 2009 UTC revision 478 by ph10, Sun Jan 3 16:05:13 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  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    
72    Version 8.00 19-Oct-09
73  ----------------------  ----------------------
74    
75  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
76      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
77      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
78      error.      error.
79    
80  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,
81      "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
82      in a Windows environment.      in a Windows environment.
83    
84  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
85      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
86      --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
87      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
88      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
89      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
90      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
91    
92  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
93      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
94      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
95      the old behaviour.      the old behaviour.
96    
97  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
98      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
99      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
100      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
101    
102  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
103      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
104    
105  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
106      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
107      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
108      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
109      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
110      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
111    
112  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
113      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
114      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
115      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
116      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
117      result.      result.
118    
119  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
120      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
121      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
122      slots in the offset vector, the offsets of the first-encountered partial      slots in the offset vector, the offset of the earliest inspected character
123      match are set in them when PCRE_ERROR_PARTIAL is returned.      for the match and the offset of the end of the subject are set in them when
124        PCRE_ERROR_PARTIAL is returned.
125    
126  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
127      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
128      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
129      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
130      pcre_exec().  
131    11. Partial matching with pcre_exec() is now more intuitive. A partial match
132  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
133      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
134      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
135      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
136      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
137      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
138      final character ended with (*FAIL).  
   
139  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
140      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
141      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
142      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
143      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
144      "sbody" failed.      "sbody" failed. This bug has been fixed.
145    
146  13. Added a pcredemo man page, created automatically from the pcredemo.c file,  13. The string returned by pcre_dfa_exec() after a partial match has been
147      so that the demonstration program is easily available in environments where      changed so that it starts at the first inspected character rather than the
148      PCRE has not been installed from source.      first character of the match. This makes a difference only if the pattern
149        starts with a lookbehind assertion or \b or \B (\K is not supported by
150  14. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,      pcre_dfa_exec()). It's an incompatible change, but it makes the two
151        matching functions compatible, and I think it's the right thing to do.
152    
153    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
154        so that the demonstration program is easily available in environments where
155        PCRE has not been installed from source.
156    
157    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
158      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
159      library.      library.
160    
161  15. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
162      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
163      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
164      these options useful.      these options useful.
165    
166    17. If a caller to the POSIX matching function regexec() passes a non-zero
167        value for nmatch with a NULL value for pmatch, the value of
168        nmatch is forced to zero.
169    
170    18. RunGrepTest did not have a test for the availability of the -u option of
171        the diff command, as RunTest does. It now checks in the same way as
172        RunTest, and also checks for the -b option.
173    
174    19. If an odd number of negated classes containing just a single character
175        interposed, within parentheses, between a forward reference to a named
176        subpattern and the definition of the subpattern, compilation crashed with
177        an internal error, complaining that it could not find the referenced
178        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
179        [The bug was that it was starting one character too far in when skipping
180        over the character class, thus treating the ] as data rather than
181        terminating the class. This meant it could skip too much.]
182    
183    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
184        /g option in pcretest when the pattern contains \K, which makes it possible
185        to have an empty string match not at the start, even when the pattern is
186        anchored. Updated pcretest and pcredemo to use this option.
187    
188    21. If the maximum number of capturing subpatterns in a recursion was greater
189        than the maximum at the outer level, the higher number was returned, but
190        with unset values at the outer level. The correct (outer level) value is
191        now given.
192    
193    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
194        PCRE did not set those parentheses (unlike Perl). I have now found a way to
195        make it do so. The string so far is captured, making this feature
196        compatible with Perl.
197    
198    23. The tests have been re-organized, adding tests 11 and 12, to make it
199        possible to check the Perl 5.10 features against Perl 5.10.
200    
201    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
202        pattern matches a fixed length string. PCRE did not allow this; now it
203        does. Neither allows recursion.
204    
205    25. I finally figured out how to implement a request to provide the minimum
206        length of subject string that was needed in order to match a given pattern.
207        (It was back references and recursion that I had previously got hung up
208        on.) This code has now been added to pcre_study(); it finds a lower bound
209        to the length of subject needed. It is not necessarily the greatest lower
210        bound, but using it to avoid searching strings that are too short does give
211        some useful speed-ups. The value is available to calling programs via
212        pcre_fullinfo().
213    
214    26. While implementing 25, I discovered to my embarrassment that pcretest had
215        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
216        study optimizations had never been tested with that matching function.
217        Oops. What is worse, even when it was passed study data, there was a bug in
218        pcre_dfa_exec() that meant it never actually used it. Double oops. There
219        were also very few tests of studied patterns with pcre_dfa_exec().
220    
221    27. If (?| is used to create subpatterns with duplicate numbers, they are now
222        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
223        on the other side of the coin, they are no longer allowed to have different
224        names, because these cannot be distinguished in PCRE, and this has caused
225        confusion. (This is a difference from Perl.)
226    
227    28. When duplicate subpattern names are present (necessarily with different
228        numbers, as required by 27 above), and a test is made by name in a
229        conditional pattern, either for a subpattern having been matched, or for
230        recursion in such a pattern, all the associated numbered subpatterns are
231        tested, and the overall condition is true if the condition is true for any
232        one of them. This is the way Perl works, and is also more like the way
233        testing by number works.
234    
235    
236  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
237  ---------------------  ---------------------

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