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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 6.7 04-Jul-06
5    ---------------------
6    
7     1. In order to handle tests when input lines are enormously long, pcretest has
8        been re-factored so that it automatically extends its buffers when
9        necessary. The code is crude, but this _is_ just a test program. The
10        default size has been increased from 32K to 50K.
11    
12     2. The code in pcre_study() was using the value of the re argument before
13        testing it for NULL. (Of course, in any sensible call of the function, it
14        won't be NULL.)
15    
16     3. The memmove() emulation function in pcre_internal.h, which is used on
17        systems that lack both memmove() and bcopy() - that is, hardly ever -
18        was missing a "static" storage class specifier.
19    
20     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
21        containing an extended class (one that cannot be represented by a bitmap
22        because it contains high-valued characters or Unicode property items, e.g.
23        [\pZ]). Almost always one would set UTF-8 mode when processing such a
24        pattern, but PCRE should not loop if you do not (it no longer does).
25        [Detail: two cases were found: (a) a repeated subpattern containing an
26        extended class; (b) a recursive reference to a subpattern that followed a
27        previous extended class. It wasn't skipping over the extended class
28        correctly when UTF-8 mode was not set.]
29    
30     5. A negated single-character class was not being recognized as fixed-length
31        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
32        compile error "lookbehind assertion is not fixed length".
33    
34     6. The RunPerlTest auxiliary script was showing an unexpected difference
35        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
36        write a Perl script that can interpret lines of an input file either as
37        byte characters or as UTF-8, which is what "perltest" was being required to
38        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
39        can't do is switch easily at run time between having the "use utf8;" pragma
40        or not. In the end, I fudged it by using the RunPerlTest script to insert
41        "use utf8;" explicitly for the UTF-8 tests.
42    
43     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
44        the end of the subject string, contrary to the documentation and to what
45        Perl does. This was true of both matching functions. Now it matches only at
46        the start of the subject and immediately after *internal* newlines.
47    
48     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
49        a pointer to an int instead of a pointer to an unsigned long int. This
50        caused problems on 64-bit systems.
51    
52     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
53        instance of the 'standard' template library not being so standard".
54    
55    10. There was no check on the number of named subpatterns nor the maximum
56        length of a subpattern name. The product of these values is used to compute
57        the size of the memory block for a compiled pattern. By supplying a very
58        long subpattern name and a large number of named subpatterns, the size
59        computation could be caused to overflow. This is now prevented by limiting
60        the length of names to 32 characters, and the number of named subpatterns
61        to 10,000.
62    
63    11. Subpatterns that are repeated with specific counts have to be replicated in
64        the compiled pattern. The size of memory for this was computed from the
65        length of the subpattern and the repeat count. The latter is limited to
66        65535, but there was no limit on the former, meaning that integer overflow
67        could in principle occur. The compiled length of a repeated subpattern is
68        now limited to 30,000 bytes in order to prevent this.
69    
70    12. Added the optional facility to have named substrings with the same name.
71    
72    13. Added the ability to use a named substring as a condition, using the
73        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
74        are numbers (not recommended). Forward references are permitted.
75    
76    14. Added forward references in named backreferences (if you see what I mean).
77    
78    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
79        pattern could run off the end of the subject. For example, the pattern
80        "(?s)(.{1,5})"8 did this with the subject "ab".
81    
82    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
83        PCRE_CASELESS was set when matching characters that were quantified with ?
84        or *.
85    
86    17. A character class other than a single negated character that had a minimum
87        but no maximum quantifier - for example [ab]{6,} - was not handled
88        correctly by pce_dfa_exec(). It would match only one character.
89    
90    18. A valid (though odd) pattern that looked like a POSIX character
91        class but used an invalid character after [ (for example [[,abc,]]) caused
92        pcre_compile() to give the error "Failed: internal error: code overflow" or
93        in some cases to crash with a glibc free() error. This could even happen if
94        the pattern terminated after [[ but there just happened to be a sequence of
95        letters, a binary zero, and a closing ] in the memory that followed.
96    
97    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
98        over the years. Originally (before any Unicode support), just the bottom 8
99        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
100        output from "man perlunicode" includes this:
101    
102          The regular expression compiler produces polymorphic opcodes.  That
103          is, the pattern adapts to the data and automatically switches to
104          the Unicode character scheme when presented with Unicode data--or
105          instead uses a traditional byte scheme when presented with byte
106          data.
107    
108        Sadly, a wide octal escape does not cause a switch, and in a string with
109        no other multibyte characters, these octal escapes are treated as before.
110        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
111        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
112        Unicode string.
113    
114        I have not perpetrated such confusion in PCRE. Up till now, it took just
115        the bottom 8 bits, as in old Perl. I have now made octal escapes with
116        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
117        translate to the appropriate multibyte character.
118    
119    29. Applied some refactoring to reduce the number of warnings from Microsoft
120        and Borland compilers. This has included removing the fudge introduced
121        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
122        a warning about an unused variable.
123    
124    21. PCRE has not included VT (character 0x0b) in the set of whitespace
125        characters since release 4.0, because Perl (from release 5.004) does not.
126        [Or at least, is documented not to: some releases seem to be in conflict
127        with the documentation.] However, when a pattern was studied with
128        pcre_study() and all its branches started with \s, PCRE still included VT
129        as a possible starting character. Of course, this did no harm; it just
130        caused an unnecessary match attempt.
131    
132    22. Removed a now-redundant internal flag bit that recorded the fact that case
133        dependency changed within the pattern. This was once needed for "required
134        byte" processing, but is no longer used. This recovers a now-scarce options
135        bit. Also moved the least significant internal flag bit to the most-
136        significant bit of the word, which was not previously used (hangover from
137        the days when it was an int rather than a uint) to free up another bit for
138        the future.
139    
140    23. Added support for CRLF line endings as well as CR and LF. As well as the
141        default being selectable at build time, it can now be changed at runtime
142        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
143        specify that it is scanning data with non-default line endings.
144    
145    24. Changed the definition of CXXLINK to make it agree with the definition of
146        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
147    
148    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
149        recursions. This makes a big different to stack usage for some patterns.
150    
151    26. If a subpattern containing a named recursion or subroutine reference such
152        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
153        the space required for the compiled pattern went wrong and gave too small a
154        value. Depending on the environment, this could lead to "Failed: internal
155        error: code overflow at offset 49" or "glibc detected double free or
156        corruption" errors.
157    
158    27. Applied patches from Google (a) to support the new newline modes and (b) to
159        advance over multibyte UTF-8 characters in GlobalReplace.
160    
161    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
162        difference for some implementation of PCRE in some Windows version.
163    
164    29. Added some extra testing facilities to pcretest:
165    
166        \q<number>   in a data line sets the "match limit" value
167        \Q<number>   in a data line sets the "match recursion limt" value
168        -S <number>  sets the stack size, where <number> is in megabytes
169    
170        The -S option isn't available for Windows.
171    
172    
173    Version 6.6 06-Feb-06
174    ---------------------
175    
176     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
177        in pcreposix.h. I have copied the definition from pcre.h.
178    
179     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
180        because pcre.h is no longer a built file.
181    
182     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
183        not normally included in the compiled code.
184    
185    
186    Version 6.5 01-Feb-06
187    ---------------------
188    
189     1. When using the partial match feature with pcre_dfa_exec(), it was not
190        anchoring the second and subsequent partial matches at the new starting
191        point. This could lead to incorrect results. For example, with the pattern
192        /1234/, partially matching against "123" and then "a4" gave a match.
193    
194     2. Changes to pcregrep:
195    
196        (a) All non-match returns from pcre_exec() were being treated as failures
197            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
198            error message is output. Some extra information is given for the
199            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
200            probably the only errors that are likely to be caused by users (by
201            specifying a regex that has nested indefinite repeats, for instance).
202            If there are more than 20 of these errors, pcregrep is abandoned.
203    
204        (b) A binary zero was treated as data while matching, but terminated the
205            output line if it was written out. This has been fixed: binary zeroes
206            are now no different to any other data bytes.
207    
208        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
209            used to set a locale for matching. The --locale=xxxx long option has
210            been added (no short equivalent) to specify a locale explicitly on the
211            pcregrep command, overriding the environment variables.
212    
213        (d) When -B was used with -n, some line numbers in the output were one less
214            than they should have been.
215    
216        (e) Added the -o (--only-matching) option.
217    
218        (f) If -A or -C was used with -c (count only), some lines of context were
219            accidentally printed for the final match.
220    
221        (g) Added the -H (--with-filename) option.
222    
223        (h) The combination of options -rh failed to suppress file names for files
224            that were found from directory arguments.
225    
226        (i) Added the -D (--devices) and -d (--directories) options.
227    
228        (j) Added the -F (--fixed-strings) option.
229    
230        (k) Allow "-" to be used as a file name for -f as well as for a data file.
231    
232        (l) Added the --colo(u)r option.
233    
234        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
235            is not present by default.
236    
237     3. A nasty bug was discovered in the handling of recursive patterns, that is,
238        items such as (?R) or (?1), when the recursion could match a number of
239        alternatives. If it matched one of the alternatives, but subsequently,
240        outside the recursion, there was a failure, the code tried to back up into
241        the recursion. However, because of the way PCRE is implemented, this is not
242        possible, and the result was an incorrect result from the match.
243    
244        In order to prevent this happening, the specification of recursion has
245        been changed so that all such subpatterns are automatically treated as
246        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
247    
248     4. I had overlooked the fact that, in some locales, there are characters for
249        which isalpha() is true but neither isupper() nor islower() are true. In
250        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
251        and ordfeminine) are like this. This affected the treatment of \w and \W
252        when they appeared in character classes, but not when they appeared outside
253        a character class. The bit map for "word" characters is now created
254        separately from the results of isalnum() instead of just taking it from the
255        upper, lower, and digit maps. (Plus the underscore character, of course.)
256    
257     5. The above bug also affected the handling of POSIX character classes such as
258        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
259        permanent tables. Instead, the bit maps for such a class were previously
260        created as the appropriate unions of the upper, lower, and digit bitmaps.
261        Now they are created by subtraction from the [[:word:]] class, which has
262        its own bitmap.
263    
264     6. The [[:blank:]] character class matches horizontal, but not vertical space.
265        It is created by subtracting the vertical space characters (\x09, \x0a,
266        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
267        subtraction was done in the overall bitmap for a character class, meaning
268        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
269        be recognized. This bug has been fixed.
270    
271     7. Patches from the folks at Google:
272    
273          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
274          real life, but is still worth protecting against".
275    
276          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
277          regular expressions".
278    
279          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
280          have it.
281    
282          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
283          "configure" and the latter not, in order to fix a problem somebody had
284          with compiling the Arg class on HP-UX.
285    
286          (e) Improve the error-handling of the C++ wrapper a little bit.
287    
288          (f) New tests for checking recursion limiting.
289    
290     8. The pcre_memmove() function, which is used only if the environment does not
291        have a standard memmove() function (and is therefore rarely compiled),
292        contained two bugs: (a) use of int instead of size_t, and (b) it was not
293        returning a result (though PCRE never actually uses the result).
294    
295     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
296        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
297        returned instead of calling malloc() with an overflowing number that would
298        most likely cause subsequent chaos.
299    
300    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
301    
302    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
303        with this option is matched, the nmatch and pmatch options of regexec() are
304        ignored.
305    
306    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
307        provided in case anyone wants to the the POSIX interface with UTF-8
308        strings.
309    
310    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
311        C++ linking (needed for some HP-UX environments).
312    
313    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
314        (unused parameter) and in the pcre_printint() function (omitted "default"
315        switch label when the default is to do nothing).
316    
317    15. Added some code to make it possible, when PCRE is compiled as a C++
318        library, to replace subject pointers for pcre_exec() with a smart pointer
319        class, thus making it possible to process discontinuous strings.
320    
321    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
322        much the same function. They were added by different people who were trying
323        to make PCRE easy to compile on non-Unix systems. It has been suggested
324        that PCRE_EXPORT be abolished now that there is more automatic apparatus
325        for compiling on Windows systems. I have therefore replaced it with
326        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
327        defaults to "extern" for C or "extern C" for C++, which works fine on
328        Unix-like systems. It is now possible to override the value of PCRE_DATA_
329        SCOPE with something explicit in config.h. In addition:
330    
331        (a) pcreposix.h still had just "extern" instead of either of these macros;
332            I have replaced it with PCRE_DATA_SCOPE.
333    
334        (b) Functions such as _pcre_xclass(), which are internal to the library,
335            but external in the C sense, all had PCRE_EXPORT in their definitions.
336            This is apparently wrong for the Windows case, so I have removed it.
337            (It makes no difference on Unix-like systems.)
338    
339    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
340        of recursive calls to match(). This is different to MATCH_LIMIT because
341        that limits the total number of calls to match(), not all of which increase
342        the depth of recursion. Limiting the recursion depth limits the amount of
343        stack (or heap if NO_RECURSE is set) that is used. The default can be set
344        when PCRE is compiled, and changed at run time. A patch from Google adds
345        this functionality to the C++ interface.
346    
347    18. Changes to the handling of Unicode character properties:
348    
349        (a) Updated the table to Unicode 4.1.0.
350    
351        (b) Recognize characters that are not in the table as "Cn" (undefined).
352    
353        (c) I revised the way the table is implemented to a much improved format
354            which includes recognition of ranges. It now supports the ranges that
355            are defined in UnicodeData.txt, and it also amalgamates other
356            characters into ranges. This has reduced the number of entries in the
357            table from around 16,000 to around 3,000, thus reducing its size
358            considerably. I realized I did not need to use a tree structure after
359            all - a binary chop search is just as efficient. Having reduced the
360            number of entries, I extended their size from 6 bytes to 8 bytes to
361            allow for more data.
362    
363        (d) Added support for Unicode script names via properties such as \p{Han}.
364    
365    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
366        matching that character.
367    
368    20. When matching a repeated Unicode property with a minimum greater than zero,
369        (for example \pL{2,}), PCRE could look past the end of the subject if it
370        reached it while seeking the minimum number of characters. This could
371        happen only if some of the characters were more than one byte long, because
372        there is a check for at least the minimum number of bytes.
373    
374    21. Refactored the implementation of \p and \P so as to be more general, to
375        allow for more different types of property in future. This has changed the
376        compiled form incompatibly. Anybody with saved compiled patterns that use
377        \p or \P will have to recompile them.
378    
379    22. Added "Any" and "L&" to the supported property types.
380    
381    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
382        but give a compile time error if the value is greater than 0xff.
383    
384    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
385        accidentally not being installed or uninstalled.
386    
387    25. The pcre.h file was built from pcre.h.in, but the only changes that were
388        made were to insert the current release number. This seemed silly, because
389        it made things harder for people building PCRE on systems that don't run
390        "configure". I have turned pcre.h into a distributed file, no longer built
391        by "configure", with the version identification directly included. There is
392        no longer a pcre.h.in file.
393    
394        However, this change necessitated a change to the pcre-config script as
395        well. It is built from pcre-config.in, and one of the substitutions was the
396        release number. I have updated configure.ac so that ./configure now finds
397        the release number by grepping pcre.h.
398    
399    26. Added the ability to run the tests under valgrind.
400    
401    
402    Version 6.4 05-Sep-05
403    ---------------------
404    
405     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
406        "--" to be printed when multiple files were scanned, even when none of the
407        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
408        consider it to be a bug, and have restored the previous behaviour.
409    
410     2. A couple of code tidies to get rid of compiler warnings.
411    
412     3. The pcretest program used to cheat by referring to symbols in the library
413        whose names begin with _pcre_. These are internal symbols that are not
414        really supposed to be visible externally, and in some environments it is
415        possible to suppress them. The cheating is now confined to including
416        certain files from the library's source, which is a bit cleaner.
417    
418     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
419        file's purpose clearer.
420    
421     5. Reorganized pcre_ucp_findchar().
422    
423    
424  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
425  ---------------------  ---------------------
426    

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