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revision 85 by nigel, Sat Feb 24 21:41:13 2007 UTC revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 6.5 01-Feb-06
5    ---------------------
6    
7     1. When using the partial match feature with pcre_dfa_exec(), it was not
8        anchoring the second and subsequent partial matches at the new starting
9        point. This could lead to incorrect results. For example, with the pattern
10        /1234/, partially matching against "123" and then "a4" gave a match.
11    
12     2. Changes to pcregrep:
13    
14        (a) All non-match returns from pcre_exec() were being treated as failures
15            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
16            error message is output. Some extra information is given for the
17            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
18            probably the only errors that are likely to be caused by users (by
19            specifying a regex that has nested indefinite repeats, for instance).
20            If there are more than 20 of these errors, pcregrep is abandoned.
21    
22        (b) A binary zero was treated as data while matching, but terminated the
23            output line if it was written out. This has been fixed: binary zeroes
24            are now no different to any other data bytes.
25    
26        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
27            used to set a locale for matching. The --locale=xxxx long option has
28            been added (no short equivalent) to specify a locale explicitly on the
29            pcregrep command, overriding the environment variables.
30    
31        (d) When -B was used with -n, some line numbers in the output were one less
32            than they should have been.
33    
34        (e) Added the -o (--only-matching) option.
35    
36        (f) If -A or -C was used with -c (count only), some lines of context were
37            accidentally printed for the final match.
38    
39        (g) Added the -H (--with-filename) option.
40    
41        (h) The combination of options -rh failed to suppress file names for files
42            that were found from directory arguments.
43    
44        (i) Added the -D (--devices) and -d (--directories) options.
45    
46        (j) Added the -F (--fixed-strings) option.
47    
48        (k) Allow "-" to be used as a file name for -f as well as for a data file.
49    
50        (l) Added the --colo(u)r option.
51    
52        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
53            is not present by default.
54    
55     3. A nasty bug was discovered in the handling of recursive patterns, that is,
56        items such as (?R) or (?1), when the recursion could match a number of
57        alternatives. If it matched one of the alternatives, but subsequently,
58        outside the recursion, there was a failure, the code tried to back up into
59        the recursion. However, because of the way PCRE is implemented, this is not
60        possible, and the result was an incorrect result from the match.
61    
62        In order to prevent this happening, the specification of recursion has
63        been changed so that all such subpatterns are automatically treated as
64        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
65    
66     4. I had overlooked the fact that, in some locales, there are characters for
67        which isalpha() is true but neither isupper() nor islower() are true. In
68        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
69        and ordfeminine) are like this. This affected the treatment of \w and \W
70        when they appeared in character classes, but not when they appeared outside
71        a character class. The bit map for "word" characters is now created
72        separately from the results of isalnum() instead of just taking it from the
73        upper, lower, and digit maps. (Plus the underscore character, of course.)
74    
75     5. The above bug also affected the handling of POSIX character classes such as
76        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
77        permanent tables. Instead, the bit maps for such a class were previously
78        created as the appropriate unions of the upper, lower, and digit bitmaps.
79        Now they are created by subtraction from the [[:word:]] class, which has
80        its own bitmap.
81    
82     6. The [[:blank:]] character class matches horizontal, but not vertical space.
83        It is created by subtracting the vertical space characters (\x09, \x0a,
84        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
85        subtraction was done in the overall bitmap for a character class, meaning
86        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
87        be recognized. This bug has been fixed.
88    
89     7. Patches from the folks at Google:
90    
91          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
92          real life, but is still worth protecting against".
93    
94          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
95          regular expressions".
96    
97          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
98          have it.
99    
100          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
101          "configure" and the latter not, in order to fix a problem somebody had
102          with compiling the Arg class on HP-UX.
103    
104          (e) Improve the error-handling of the C++ wrapper a little bit.
105    
106          (f) New tests for checking recursion limiting.
107    
108     8. The pcre_memmove() function, which is used only if the environment does not
109        have a standard memmove() function (and is therefore rarely compiled),
110        contained two bugs: (a) use of int instead of size_t, and (b) it was not
111        returning a result (though PCRE never actually uses the result).
112    
113     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
114        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
115        returned instead of calling malloc() with an overflowing number that would
116        most likely cause subsequent chaos.
117    
118    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
119    
120    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
121        with this option is matched, the nmatch and pmatch options of regexec() are
122        ignored.
123    
124    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
125        provided in case anyone wants to the the POSIX interface with UTF-8
126        strings.
127    
128    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
129        C++ linking (needed for some HP-UX environments).
130    
131    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
132        (unused parameter) and in the pcre_printint() function (omitted "default"
133        switch label when the default is to do nothing).
134    
135    15. Added some code to make it possible, when PCRE is compiled as a C++
136        library, to replace subject pointers for pcre_exec() with a smart pointer
137        class, thus making it possible to process discontinuous strings.
138    
139    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
140        much the same function. They were added by different people who were trying
141        to make PCRE easy to compile on non-Unix systems. It has been suggested
142        that PCRE_EXPORT be abolished now that there is more automatic apparatus
143        for compiling on Windows systems. I have therefore replaced it with
144        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
145        defaults to "extern" for C or "extern C" for C++, which works fine on
146        Unix-like systems. It is now possible to override the value of PCRE_DATA_
147        SCOPE with something explicit in config.h. In addition:
148    
149        (a) pcreposix.h still had just "extern" instead of either of these macros;
150            I have replaced it with PCRE_DATA_SCOPE.
151    
152        (b) Functions such as _pcre_xclass(), which are internal to the library,
153            but external in the C sense, all had PCRE_EXPORT in their definitions.
154            This is apparently wrong for the Windows case, so I have removed it.
155            (It makes no difference on Unix-like systems.)
156    
157    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
158        of recursive calls to match(). This is different to MATCH_LIMIT because
159        that limits the total number of calls to match(), not all of which increase
160        the depth of recursion. Limiting the recursion depth limits the amount of
161        stack (or heap if NO_RECURSE is set) that is used. The default can be set
162        when PCRE is compiled, and changed at run time. A patch from Google adds
163        this functionality to the C++ interface.
164    
165    18. Changes to the handling of Unicode character properties:
166    
167        (a) Updated the table to Unicode 4.1.0.
168    
169        (b) Recognize characters that are not in the table as "Cn" (undefined).
170    
171        (c) I revised the way the table is implemented to a much improved format
172            which includes recognition of ranges. It now supports the ranges that
173            are defined in UnicodeData.txt, and it also amalgamates other
174            characters into ranges. This has reduced the number of entries in the
175            table from around 16,000 to around 3,000, thus reducing its size
176            considerably. I realized I did not need to use a tree structure after
177            all - a binary chop search is just as efficient. Having reduced the
178            number of entries, I extended their size from 6 bytes to 8 bytes to
179            allow for more data.
180    
181        (d) Added support for Unicode script names via properties such as \p{Han}.
182    
183    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
184        matching that character.
185    
186    20. When matching a repeated Unicode property with a minimum greater than zero,
187        (for example \pL{2,}), PCRE could look past the end of the subject if it
188        reached it while seeking the minimum number of characters. This could
189        happen only if some of the characters were more than one byte long, because
190        there is a check for at least the minimum number of bytes.
191    
192    21. Refactored the implementation of \p and \P so as to be more general, to
193        allow for more different types of property in future. This has changed the
194        compiled form incompatibly. Anybody with saved compiled patterns that use
195        \p or \P will have to recompile them.
196    
197    22. Added "Any" and "L&" to the supported property types.
198    
199    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
200        but give a compile time error if the value is greater than 0xff.
201    
202    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
203        accidentally not being installed or uninstalled.
204    
205    25. The pcre.h file was built from pcre.h.in, but the only changes that were
206        made were to insert the current release number. This seemed silly, because
207        it made things harder for people building PCRE on systems that don't run
208        "configure". I have turned pcre.h into a distributed file, no longer built
209        by "configure", with the version identification directly included. There is
210        no longer a pcre.h.in file.
211    
212        However, this change necessitated a change to the pcre-config script as
213        well. It is built from pcre-config.in, and one of the substitutions was the
214        release number. I have updated configure.ac so that ./configure now finds
215        the release number by grepping pcre.h.
216    
217    26. Added the ability to run the tests under valgrind.
218    
219    
220  Version 6.4 05-Sep-05  Version 6.4 05-Sep-05
221  ---------------------  ---------------------
222    

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