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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.0 19-Dec-06
5    ---------------------
6    
7     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
8        moving to gcc 4.1.1.
9    
10     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
11        sys/time.h, which is documented as needed for this function. It doesn't
12        seem to matter on Linux, but it showed up on some releases of OS X.
13    
14     3. It seems that there are systems where bytes whose values are greater than
15        127 match isprint() in the "C" locale. The "C" locale should be the
16        default when a C program starts up. In most systems, only ASCII printing
17        characters match isprint(). This difference caused the output from pcretest
18        to vary, making some of the tests fail. I have changed pcretest so that:
19    
20        (a) When it is outputting text in the compiled version of a pattern, bytes
21            other than 32-126 are always shown as hex escapes.
22    
23        (b) When it is outputting text that is a matched part of a subject string,
24            it does the same, unless a different locale has been set for the match
25            (using the /L modifier). In this case, it uses isprint() to decide.
26    
27     4. Fixed a major bug that caused incorrect computation of the amount of memory
28        required for a compiled pattern when options that changed within the
29        pattern affected the logic of the preliminary scan that determines the
30        length. The relevant options are -x, and -i in UTF-8 mode. The result was
31        that the computed length was too small. The symptoms of this bug were
32        either the PCRE error "internal error: code overflow" from pcre_compile(),
33        or a glibc crash with a message such as "pcretest: free(): invalid next
34        size (fast)". Examples of patterns that provoked this bug (shown in
35        pcretest format) are:
36    
37          /(?-x: )/x
38          /(?x)(?-x: \s*#\s*)/
39          /((?i)[\x{c0}])/8
40          /(?i:[\x{c0}])/8
41    
42        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
43        is now done differently.
44    
45     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
46        wrapper classes; (b) implement a new function in the C++ scanner that is
47        more efficient than the old way of doing things because it avoids levels of
48        recursion in the regex matching; (c) add a paragraph to the documentation
49        for the FullMatch() function.
50    
51     6. The escape sequence \n was being treated as whatever was defined as
52        "newline". Not only was this contrary to the documentation, which states
53        that \n is character 10 (hex 0A), but it also went horribly wrong when
54        "newline" was defined as CRLF. This has been fixed.
55    
56     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
57        was being set to -1 for the "end of line" case (supposedly a value that no
58        character can have). Though this value is never used (the check for end of
59        line is "zero bytes in current character"), it caused compiler complaints.
60        I've changed it to 0xffffffff.
61    
62     8. In pcre_version.c, the version string was being built by a sequence of
63        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
64        string (as it is for production releases) called a macro with an empty
65        argument. The C standard says the result of this is undefined. The gcc
66        compiler treats it as an empty string (which was what was wanted) but it is
67        reported that Visual C gives an error. The source has been hacked around to
68        avoid this problem.
69    
70     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
71        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
72        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
73        of them did).
74    
75    10. Originally, pcretest opened its input and output without "b"; then I was
76        told that "b" was needed in some environments, so it was added for release
77        5.0 to both the input and output. (It makes no difference on Unix-like
78        systems.) Later I was told that it is wrong for the input on Windows. I've
79        now abstracted the modes into two macros, to make it easier to fiddle with
80        them, and removed "b" from the input mode under Windows.
81    
82    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
83    
84    12. Added -help and --help to pcretest as an official way of being reminded
85        of the options.
86    
87    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
88        and pcrecpp.cc because they annoy compilers at high warning levels.
89    
90    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
91    
92    15. Fixed an occurrence of == in configure.ac that should have been = (shell
93        scripts are not C programs :-) and which was not noticed because it works
94        on Linux.
95    
96    16. pcretest is supposed to handle any length of pattern and data line (as one
97        line or as a continued sequence of lines) by extending its input buffer if
98        necessary. This feature was broken for very long pattern lines, leading to
99        a string of junk being passed to pcre_compile() if the pattern was longer
100        than about 50K.
101    
102    17. I have done a major re-factoring of the way pcre_compile() computes the
103        amount of memory needed for a compiled pattern. Previously, there was code
104        that made a preliminary scan of the pattern in order to do this. That was
105        OK when PCRE was new, but as the facilities have expanded, it has become
106        harder and harder to keep it in step with the real compile phase, and there
107        have been a number of bugs (see for example, 4 above). I have now found a
108        cunning way of running the real compile function in a "fake" mode that
109        enables it to compute how much memory it would need, while actually only
110        ever using a few hundred bytes of working memory and without too many
111        tests of the mode. This should make future maintenance and development
112        easier. A side effect of this work is that the limit of 200 on the nesting
113        depth of parentheses has been removed (though this was never a serious
114        limitation, I suspect). However, there is a downside: pcre_compile() now
115        runs more slowly than before (30% or more, depending on the pattern). I
116        hope this isn't a big issue. There is no effect on runtime performance.
117    
118    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
119        newline (only possible for the last line of a file) and it was a
120        pattern that set a locale (followed by /Lsomething), pcretest crashed.
121    
122    19. Added additional timing features to pcretest. (1) The -tm option now times
123        matching only, not compiling. (2) Both -t and -tm can be followed, as a
124        separate command line item, by a number that specifies the number of
125        repeats to use when timing. The default is 50000; this gives better
126        precision, but takes uncomfortably long for very large patterns.
127    
128    20. Extended pcre_study() to be more clever in cases where a branch of a
129        subpattern has no definite first character. For example, (a*|b*)[cd] would
130        previously give no result from pcre_study(). Now it recognizes that the
131        first character must be a, b, c, or d.
132    
133    21. There was an incorrect error "recursive call could loop indefinitely" if
134        a subpattern (or the entire pattern) that was being tested for matching an
135        empty string contained only one non-empty item after a nested subpattern.
136        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
137        incorrectly, because the \d was being skipped in the check.
138    
139    22. The pcretest program now has a new pattern option /B and a command line
140        option -b, which is equivalent to adding /B to every pattern. This causes
141        it to show the compiled bytecode, without the additional information that
142        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
143        is the same as /B/I).
144    
145    23. A new optimization is now able automatically to treat some sequences such
146        as a*b as a*+b. More specifically, if something simple (such as a character
147        or a simple class like \d) has an unlimited quantifier, and is followed by
148        something that cannot possibly match the quantified thing, the quantifier
149        is automatically "possessified".
150    
151    24. A recursive reference to a subpattern whose number was greater than 39
152        went wrong under certain circumstances in UTF-8 mode. This bug could also
153        have affected the operation of pcre_study().
154    
155    25. Realized that a little bit of performance could be had by replacing
156        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
157    
158    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
159    
160    27. Possessive quantifiers such as a++ were previously implemented by turning
161        them into atomic groups such as ($>a+). Now they have their own opcodes,
162        which improves performance. This includes the automatically created ones
163        from 23 above.
164    
165    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
166        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
167        the first matched character to be a colon. This applied both to named and
168        numbered groups.
169    
170    29. The ucpinternal.h header file was missing its idempotency #ifdef.
171    
172    30. I was sent a "project" file called libpcre.a.dev which I understand makes
173        building PCRE on Windows easier, so I have included it in the distribution.
174    
175    31. There is now a check in pcretest against a ridiculously large number being
176        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
177        loop, the loop is abandoned.
178    
179    32. Forward references to subpatterns in conditions such as (?(2)...) where
180        subpattern 2 is defined later cause pcre_compile() to search forwards in
181        the pattern for the relevant set of parentheses. This search went wrong
182        when there were unescaped parentheses in a character class, parentheses
183        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
184    
185    33. "Subroutine" calls and backreferences were previously restricted to
186        referencing subpatterns earlier in the regex. This restriction has now
187        been removed.
188    
189    34. Added a number of extra features that are going to be in Perl 5.10. On the
190        whole, these are just syntactic alternatives for features that PCRE had
191        previously implemented using the Python syntax or my own invention. The
192        other formats are all retained for compatibility.
193    
194        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
195            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
196            also .NET compatible.
197    
198        (b) A recursion or subroutine call to a named group can now be defined as
199            (?&name) as well as (?P>name).
200    
201        (c) A backreference to a named group can now be defined as \k<name> or
202            \k'name' as well as (?P=name). The new forms, as well as being in Perl
203            5.10, are also .NET compatible.
204    
205        (d) A conditional reference to a named group can now use the syntax
206            (?(<name>) or (?('name') as well as (?(name).
207    
208        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
209            groups (named and numbered) that are never evaluated inline, but can be
210            called as "subroutines" from elsewhere. In effect, the DEFINE condition
211            is always false. There may be only one alternative in such a group.
212    
213        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
214            as the simple (?(R). The condition is true only if the most recent
215            recursion is that of the given number or name. It does not search out
216            through the entire recursion stack.
217    
218        (g) The escape \gN or \g{N} has been added, where N is a positive or
219            negative number, specifying an absolute or relative reference.
220    
221    35. Tidied to get rid of some further signed/unsigned compiler warnings and
222        some "unreachable code" warnings.
223    
224    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
225        things, this adds five new scripts.
226    
227    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
228        There were also incompatibilities regarding the handling of \Q..\E inside
229        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
230        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
231    
232    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
233        matches an empty string, and forcibly breaks the loop. There were bugs in
234        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
235        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
236        separate and independent bugs (that affected different cases) have been
237        fixed.
238    
239    39. Refactored the code to abolish the use of different opcodes for small
240        capturing bracket numbers. This is a tidy that I avoided doing when I
241        removed the limit on the number of capturing brackets for 3.5 back in 2001.
242        The new approach is not only tidier, it makes it possible to reduce the
243        memory needed to fix the previous bug (38).
244    
245    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
246        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
247        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
248        mode.
249    
250    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
251        report.
252    
253    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
254        copy construction and assignment in the C++ wrapper.
255    
256    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
257        couple of bugs that could have given wrong results in the "--newline=crlf"
258        case.
259    
260    44. Added a number of casts and did some reorganization of signed/unsigned int
261        variables following suggestions from Dair Grant. Also renamed the variable
262        "this" as "item" because it is a C++ keyword.
263    
264    45. Arranged for dftables to add
265    
266          #include "pcre_internal.h"
267    
268        to pcre_chartables.c because without it, gcc 4.x may remove the array
269        definition from the final binary if PCRE is built into a static library and
270        dead code stripping is activated.
271    
272    46. For an unanchored pattern, if a match attempt fails at the start of a
273        newline sequence, and the newline setting is CRLF or ANY, and the next two
274        characters are CRLF, advance by two characters instead of one.
275    
276    
277    Version 6.7 04-Jul-06
278    ---------------------
279    
280     1. In order to handle tests when input lines are enormously long, pcretest has
281        been re-factored so that it automatically extends its buffers when
282        necessary. The code is crude, but this _is_ just a test program. The
283        default size has been increased from 32K to 50K.
284    
285     2. The code in pcre_study() was using the value of the re argument before
286        testing it for NULL. (Of course, in any sensible call of the function, it
287        won't be NULL.)
288    
289     3. The memmove() emulation function in pcre_internal.h, which is used on
290        systems that lack both memmove() and bcopy() - that is, hardly ever -
291        was missing a "static" storage class specifier.
292    
293     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
294        containing an extended class (one that cannot be represented by a bitmap
295        because it contains high-valued characters or Unicode property items, e.g.
296        [\pZ]). Almost always one would set UTF-8 mode when processing such a
297        pattern, but PCRE should not loop if you do not (it no longer does).
298        [Detail: two cases were found: (a) a repeated subpattern containing an
299        extended class; (b) a recursive reference to a subpattern that followed a
300        previous extended class. It wasn't skipping over the extended class
301        correctly when UTF-8 mode was not set.]
302    
303     5. A negated single-character class was not being recognized as fixed-length
304        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
305        compile error "lookbehind assertion is not fixed length".
306    
307     6. The RunPerlTest auxiliary script was showing an unexpected difference
308        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
309        write a Perl script that can interpret lines of an input file either as
310        byte characters or as UTF-8, which is what "perltest" was being required to
311        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
312        can't do is switch easily at run time between having the "use utf8;" pragma
313        or not. In the end, I fudged it by using the RunPerlTest script to insert
314        "use utf8;" explicitly for the UTF-8 tests.
315    
316     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
317        the end of the subject string, contrary to the documentation and to what
318        Perl does. This was true of both matching functions. Now it matches only at
319        the start of the subject and immediately after *internal* newlines.
320    
321     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
322        a pointer to an int instead of a pointer to an unsigned long int. This
323        caused problems on 64-bit systems.
324    
325     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
326        instance of the 'standard' template library not being so standard".
327    
328    10. There was no check on the number of named subpatterns nor the maximum
329        length of a subpattern name. The product of these values is used to compute
330        the size of the memory block for a compiled pattern. By supplying a very
331        long subpattern name and a large number of named subpatterns, the size
332        computation could be caused to overflow. This is now prevented by limiting
333        the length of names to 32 characters, and the number of named subpatterns
334        to 10,000.
335    
336    11. Subpatterns that are repeated with specific counts have to be replicated in
337        the compiled pattern. The size of memory for this was computed from the
338        length of the subpattern and the repeat count. The latter is limited to
339        65535, but there was no limit on the former, meaning that integer overflow
340        could in principle occur. The compiled length of a repeated subpattern is
341        now limited to 30,000 bytes in order to prevent this.
342    
343    12. Added the optional facility to have named substrings with the same name.
344    
345    13. Added the ability to use a named substring as a condition, using the
346        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
347        are numbers (not recommended). Forward references are permitted.
348    
349    14. Added forward references in named backreferences (if you see what I mean).
350    
351    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
352        pattern could run off the end of the subject. For example, the pattern
353        "(?s)(.{1,5})"8 did this with the subject "ab".
354    
355    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
356        PCRE_CASELESS was set when matching characters that were quantified with ?
357        or *.
358    
359    17. A character class other than a single negated character that had a minimum
360        but no maximum quantifier - for example [ab]{6,} - was not handled
361        correctly by pce_dfa_exec(). It would match only one character.
362    
363    18. A valid (though odd) pattern that looked like a POSIX character
364        class but used an invalid character after [ (for example [[,abc,]]) caused
365        pcre_compile() to give the error "Failed: internal error: code overflow" or
366        in some cases to crash with a glibc free() error. This could even happen if
367        the pattern terminated after [[ but there just happened to be a sequence of
368        letters, a binary zero, and a closing ] in the memory that followed.
369    
370    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
371        over the years. Originally (before any Unicode support), just the bottom 8
372        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
373        output from "man perlunicode" includes this:
374    
375          The regular expression compiler produces polymorphic opcodes.  That
376          is, the pattern adapts to the data and automatically switches to
377          the Unicode character scheme when presented with Unicode data--or
378          instead uses a traditional byte scheme when presented with byte
379          data.
380    
381        Sadly, a wide octal escape does not cause a switch, and in a string with
382        no other multibyte characters, these octal escapes are treated as before.
383        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
384        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
385        Unicode string.
386    
387        I have not perpetrated such confusion in PCRE. Up till now, it took just
388        the bottom 8 bits, as in old Perl. I have now made octal escapes with
389        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
390        translate to the appropriate multibyte character.
391    
392    29. Applied some refactoring to reduce the number of warnings from Microsoft
393        and Borland compilers. This has included removing the fudge introduced
394        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
395        a warning about an unused variable.
396    
397    21. PCRE has not included VT (character 0x0b) in the set of whitespace
398        characters since release 4.0, because Perl (from release 5.004) does not.
399        [Or at least, is documented not to: some releases seem to be in conflict
400        with the documentation.] However, when a pattern was studied with
401        pcre_study() and all its branches started with \s, PCRE still included VT
402        as a possible starting character. Of course, this did no harm; it just
403        caused an unnecessary match attempt.
404    
405    22. Removed a now-redundant internal flag bit that recorded the fact that case
406        dependency changed within the pattern. This was once needed for "required
407        byte" processing, but is no longer used. This recovers a now-scarce options
408        bit. Also moved the least significant internal flag bit to the most-
409        significant bit of the word, which was not previously used (hangover from
410        the days when it was an int rather than a uint) to free up another bit for
411        the future.
412    
413    23. Added support for CRLF line endings as well as CR and LF. As well as the
414        default being selectable at build time, it can now be changed at runtime
415        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
416        specify that it is scanning data with non-default line endings.
417    
418    24. Changed the definition of CXXLINK to make it agree with the definition of
419        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
420    
421    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
422        recursions. This makes a big different to stack usage for some patterns.
423    
424    26. If a subpattern containing a named recursion or subroutine reference such
425        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
426        the space required for the compiled pattern went wrong and gave too small a
427        value. Depending on the environment, this could lead to "Failed: internal
428        error: code overflow at offset 49" or "glibc detected double free or
429        corruption" errors.
430    
431    27. Applied patches from Google (a) to support the new newline modes and (b) to
432        advance over multibyte UTF-8 characters in GlobalReplace.
433    
434    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
435        difference for some implementation of PCRE in some Windows version.
436    
437    29. Added some extra testing facilities to pcretest:
438    
439        \q<number>   in a data line sets the "match limit" value
440        \Q<number>   in a data line sets the "match recursion limt" value
441        -S <number>  sets the stack size, where <number> is in megabytes
442    
443        The -S option isn't available for Windows.
444    
445    
446    Version 6.6 06-Feb-06
447    ---------------------
448    
449     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
450        in pcreposix.h. I have copied the definition from pcre.h.
451    
452     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
453        because pcre.h is no longer a built file.
454    
455     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
456        not normally included in the compiled code.
457    
458    
459    Version 6.5 01-Feb-06
460    ---------------------
461    
462     1. When using the partial match feature with pcre_dfa_exec(), it was not
463        anchoring the second and subsequent partial matches at the new starting
464        point. This could lead to incorrect results. For example, with the pattern
465        /1234/, partially matching against "123" and then "a4" gave a match.
466    
467     2. Changes to pcregrep:
468    
469        (a) All non-match returns from pcre_exec() were being treated as failures
470            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
471            error message is output. Some extra information is given for the
472            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
473            probably the only errors that are likely to be caused by users (by
474            specifying a regex that has nested indefinite repeats, for instance).
475            If there are more than 20 of these errors, pcregrep is abandoned.
476    
477        (b) A binary zero was treated as data while matching, but terminated the
478            output line if it was written out. This has been fixed: binary zeroes
479            are now no different to any other data bytes.
480    
481        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
482            used to set a locale for matching. The --locale=xxxx long option has
483            been added (no short equivalent) to specify a locale explicitly on the
484            pcregrep command, overriding the environment variables.
485    
486        (d) When -B was used with -n, some line numbers in the output were one less
487            than they should have been.
488    
489        (e) Added the -o (--only-matching) option.
490    
491        (f) If -A or -C was used with -c (count only), some lines of context were
492            accidentally printed for the final match.
493    
494        (g) Added the -H (--with-filename) option.
495    
496        (h) The combination of options -rh failed to suppress file names for files
497            that were found from directory arguments.
498    
499        (i) Added the -D (--devices) and -d (--directories) options.
500    
501        (j) Added the -F (--fixed-strings) option.
502    
503        (k) Allow "-" to be used as a file name for -f as well as for a data file.
504    
505        (l) Added the --colo(u)r option.
506    
507        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
508            is not present by default.
509    
510     3. A nasty bug was discovered in the handling of recursive patterns, that is,
511        items such as (?R) or (?1), when the recursion could match a number of
512        alternatives. If it matched one of the alternatives, but subsequently,
513        outside the recursion, there was a failure, the code tried to back up into
514        the recursion. However, because of the way PCRE is implemented, this is not
515        possible, and the result was an incorrect result from the match.
516    
517        In order to prevent this happening, the specification of recursion has
518        been changed so that all such subpatterns are automatically treated as
519        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
520    
521     4. I had overlooked the fact that, in some locales, there are characters for
522        which isalpha() is true but neither isupper() nor islower() are true. In
523        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
524        and ordfeminine) are like this. This affected the treatment of \w and \W
525        when they appeared in character classes, but not when they appeared outside
526        a character class. The bit map for "word" characters is now created
527        separately from the results of isalnum() instead of just taking it from the
528        upper, lower, and digit maps. (Plus the underscore character, of course.)
529    
530     5. The above bug also affected the handling of POSIX character classes such as
531        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
532        permanent tables. Instead, the bit maps for such a class were previously
533        created as the appropriate unions of the upper, lower, and digit bitmaps.
534        Now they are created by subtraction from the [[:word:]] class, which has
535        its own bitmap.
536    
537     6. The [[:blank:]] character class matches horizontal, but not vertical space.
538        It is created by subtracting the vertical space characters (\x09, \x0a,
539        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
540        subtraction was done in the overall bitmap for a character class, meaning
541        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
542        be recognized. This bug has been fixed.
543    
544     7. Patches from the folks at Google:
545    
546          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
547          real life, but is still worth protecting against".
548    
549          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
550          regular expressions".
551    
552          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
553          have it.
554    
555          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
556          "configure" and the latter not, in order to fix a problem somebody had
557          with compiling the Arg class on HP-UX.
558    
559          (e) Improve the error-handling of the C++ wrapper a little bit.
560    
561          (f) New tests for checking recursion limiting.
562    
563     8. The pcre_memmove() function, which is used only if the environment does not
564        have a standard memmove() function (and is therefore rarely compiled),
565        contained two bugs: (a) use of int instead of size_t, and (b) it was not
566        returning a result (though PCRE never actually uses the result).
567    
568     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
569        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
570        returned instead of calling malloc() with an overflowing number that would
571        most likely cause subsequent chaos.
572    
573    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
574    
575    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
576        with this option is matched, the nmatch and pmatch options of regexec() are
577        ignored.
578    
579    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
580        provided in case anyone wants to the the POSIX interface with UTF-8
581        strings.
582    
583    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
584        C++ linking (needed for some HP-UX environments).
585    
586    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
587        (unused parameter) and in the pcre_printint() function (omitted "default"
588        switch label when the default is to do nothing).
589    
590    15. Added some code to make it possible, when PCRE is compiled as a C++
591        library, to replace subject pointers for pcre_exec() with a smart pointer
592        class, thus making it possible to process discontinuous strings.
593    
594    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
595        much the same function. They were added by different people who were trying
596        to make PCRE easy to compile on non-Unix systems. It has been suggested
597        that PCRE_EXPORT be abolished now that there is more automatic apparatus
598        for compiling on Windows systems. I have therefore replaced it with
599        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
600        defaults to "extern" for C or "extern C" for C++, which works fine on
601        Unix-like systems. It is now possible to override the value of PCRE_DATA_
602        SCOPE with something explicit in config.h. In addition:
603    
604        (a) pcreposix.h still had just "extern" instead of either of these macros;
605            I have replaced it with PCRE_DATA_SCOPE.
606    
607        (b) Functions such as _pcre_xclass(), which are internal to the library,
608            but external in the C sense, all had PCRE_EXPORT in their definitions.
609            This is apparently wrong for the Windows case, so I have removed it.
610            (It makes no difference on Unix-like systems.)
611    
612    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
613        of recursive calls to match(). This is different to MATCH_LIMIT because
614        that limits the total number of calls to match(), not all of which increase
615        the depth of recursion. Limiting the recursion depth limits the amount of
616        stack (or heap if NO_RECURSE is set) that is used. The default can be set
617        when PCRE is compiled, and changed at run time. A patch from Google adds
618        this functionality to the C++ interface.
619    
620    18. Changes to the handling of Unicode character properties:
621    
622        (a) Updated the table to Unicode 4.1.0.
623    
624        (b) Recognize characters that are not in the table as "Cn" (undefined).
625    
626        (c) I revised the way the table is implemented to a much improved format
627            which includes recognition of ranges. It now supports the ranges that
628            are defined in UnicodeData.txt, and it also amalgamates other
629            characters into ranges. This has reduced the number of entries in the
630            table from around 16,000 to around 3,000, thus reducing its size
631            considerably. I realized I did not need to use a tree structure after
632            all - a binary chop search is just as efficient. Having reduced the
633            number of entries, I extended their size from 6 bytes to 8 bytes to
634            allow for more data.
635    
636        (d) Added support for Unicode script names via properties such as \p{Han}.
637    
638    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
639        matching that character.
640    
641    20. When matching a repeated Unicode property with a minimum greater than zero,
642        (for example \pL{2,}), PCRE could look past the end of the subject if it
643        reached it while seeking the minimum number of characters. This could
644        happen only if some of the characters were more than one byte long, because
645        there is a check for at least the minimum number of bytes.
646    
647    21. Refactored the implementation of \p and \P so as to be more general, to
648        allow for more different types of property in future. This has changed the
649        compiled form incompatibly. Anybody with saved compiled patterns that use
650        \p or \P will have to recompile them.
651    
652    22. Added "Any" and "L&" to the supported property types.
653    
654    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
655        but give a compile time error if the value is greater than 0xff.
656    
657    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
658        accidentally not being installed or uninstalled.
659    
660    25. The pcre.h file was built from pcre.h.in, but the only changes that were
661        made were to insert the current release number. This seemed silly, because
662        it made things harder for people building PCRE on systems that don't run
663        "configure". I have turned pcre.h into a distributed file, no longer built
664        by "configure", with the version identification directly included. There is
665        no longer a pcre.h.in file.
666    
667        However, this change necessitated a change to the pcre-config script as
668        well. It is built from pcre-config.in, and one of the substitutions was the
669        release number. I have updated configure.ac so that ./configure now finds
670        the release number by grepping pcre.h.
671    
672    26. Added the ability to run the tests under valgrind.
673    
674    
675    Version 6.4 05-Sep-05
676    ---------------------
677    
678     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
679        "--" to be printed when multiple files were scanned, even when none of the
680        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
681        consider it to be a bug, and have restored the previous behaviour.
682    
683     2. A couple of code tidies to get rid of compiler warnings.
684    
685     3. The pcretest program used to cheat by referring to symbols in the library
686        whose names begin with _pcre_. These are internal symbols that are not
687        really supposed to be visible externally, and in some environments it is
688        possible to suppress them. The cheating is now confined to including
689        certain files from the library's source, which is a bit cleaner.
690    
691     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
692        file's purpose clearer.
693    
694     5. Reorganized pcre_ucp_findchar().
695    
696    
697    Version 6.3 15-Aug-05
698    ---------------------
699    
700     1. The file libpcre.pc.in did not have general read permission in the tarball.
701    
702     2. There were some problems when building without C++ support:
703    
704        (a) If C++ support was not built, "make install" and "make test" still
705            tried to test it.
706    
707        (b) There were problems when the value of CXX was explicitly set. Some
708            changes have been made to try to fix these, and ...
709    
710        (c) --disable-cpp can now be used to explicitly disable C++ support.
711    
712        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
713            backslash in a target when C++ was disabled. This confuses some
714            versions of "make", apparently. Using an intermediate variable solves
715            this. (Same for CPP_LOBJ.)
716    
717     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
718        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
719        necessary on certain architectures.
720    
721     4. Added a setting of -export-symbols-regex to the link command to remove
722        those symbols that are exported in the C sense, but actually are local
723        within the library, and not documented. Their names all begin with
724        "_pcre_". This is not a perfect job, because (a) we have to except some
725        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
726        available (and never for static libraries). I have made a note to try to
727        find a way round (a) in the future.
728    
729    
730  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
731  ---------------------  ---------------------
732    

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