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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.1 05-Mar-07
5    ---------------------
6    
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8        that is more "standard", making use of automake and other autotools. There
9        is some re-arrangement of the files and adjustment of comments consequent
10        on this.
11    
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13        for recursive directory scanning broke on some systems because the files
14        are not scanned in any specific order and on different systems the order
15        was different. A call to "sort" has been inserted into RunGrepTest for the
16        approprate test as a short-term fix. In the longer term there may be an
17        alternative.
18    
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20        man pages to HTML (despite the fact that I distribute HTML pages, some
21        people do their own conversions for various reasons). The problems
22        concerned the use of low-level troff macros .br and .in. I have therefore
23        removed all such uses from the man pages (some were redundant, some could
24        be replaced by .nf/.fi pairs). The 132html script that I use to generate
25        HTML has been updated to handle .nf/.fi and to complain if it encounters
26        .br or .in.
27    
28     4. Updated comments in configure.ac that get placed in config.h.in and also
29        arranged for config.h to be included in the distribution, with the name
30        config.h.generic, for the benefit of those who have to compile without
31        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
32    
33     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
34        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
35        makevp.bat for the current PCRE, using the additional files !compile.txt,
36        !linklib.txt, and pcregexp.pas.
37    
38     6. A Windows user reported a minor discrepancy with test 2, which turned out
39        to be caused by a trailing space on an input line that had got lost in his
40        copy. The trailing space was an accident, so I've just removed it.
41    
42     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
43        that is needed.
44    
45     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
46        as "const" (a) because they are and (b) because it helps the PHP
47        maintainers who have recently made a script to detect big data structures
48        in the php code that should be moved to the .rodata section. I remembered
49        to update Builducptable as well, so it won't revert if ucptable.h is ever
50        re-created.
51    
52     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
53        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
54        order to be able to cut out the UTF-8 tables in the latter when UTF-8
55        support is not required. This saves 1.5-2K of code, which is important in
56        some applications.
57    
58        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
59        so as not to refer to the tables, even though these functions will never be
60        called when UTF-8 support is disabled. Otherwise there are problems with a
61        shared library.
62    
63    10. The emulated memmove() function in pcre_internal.h (provided for those
64        environments that have neither memmove() nor bcopy()) was defining its
65        arguments as char * instead of void *.
66    
67    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
68        and Detrail to create the HTML documentation, the .txt form of the man
69        pages, and it removes trailing spaces from listed files. It also creates
70        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
71        case, it wraps all the #defines with #ifndefs. This script should be run
72        before "make dist".
73    
74    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
75        with Unicode property support.
76    
77        (a) For a maximizing quantifier, if the two different cases of the
78            character were of different lengths in their UTF-8 codings (there are
79            some cases like this - I found 11), and the matching function had to
80            back up over a mixture of the two cases, it incorrectly assumed they
81            were both the same length.
82    
83        (b) When PCRE was configured to use the heap rather than the stack for
84            recursion during matching, it was not correctly preserving the data for
85            the other case of a UTF-8 character when checking ahead for a match
86            while processing a minimizing repeat. If the check also involved
87            matching a wide character, but failed, corruption could cause an
88            erroneous result when trying to check for a repeat of the original
89            character.
90    
91    
92    Version 7.0 19-Dec-06
93    ---------------------
94    
95     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
96        moving to gcc 4.1.1.
97    
98     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
99        sys/time.h, which is documented as needed for this function. It doesn't
100        seem to matter on Linux, but it showed up on some releases of OS X.
101    
102     3. It seems that there are systems where bytes whose values are greater than
103        127 match isprint() in the "C" locale. The "C" locale should be the
104        default when a C program starts up. In most systems, only ASCII printing
105        characters match isprint(). This difference caused the output from pcretest
106        to vary, making some of the tests fail. I have changed pcretest so that:
107    
108        (a) When it is outputting text in the compiled version of a pattern, bytes
109            other than 32-126 are always shown as hex escapes.
110    
111        (b) When it is outputting text that is a matched part of a subject string,
112            it does the same, unless a different locale has been set for the match
113            (using the /L modifier). In this case, it uses isprint() to decide.
114    
115     4. Fixed a major bug that caused incorrect computation of the amount of memory
116        required for a compiled pattern when options that changed within the
117        pattern affected the logic of the preliminary scan that determines the
118        length. The relevant options are -x, and -i in UTF-8 mode. The result was
119        that the computed length was too small. The symptoms of this bug were
120        either the PCRE error "internal error: code overflow" from pcre_compile(),
121        or a glibc crash with a message such as "pcretest: free(): invalid next
122        size (fast)". Examples of patterns that provoked this bug (shown in
123        pcretest format) are:
124    
125          /(?-x: )/x
126          /(?x)(?-x: \s*#\s*)/
127          /((?i)[\x{c0}])/8
128          /(?i:[\x{c0}])/8
129    
130        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
131        is now done differently.
132    
133     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
134        wrapper classes; (b) implement a new function in the C++ scanner that is
135        more efficient than the old way of doing things because it avoids levels of
136        recursion in the regex matching; (c) add a paragraph to the documentation
137        for the FullMatch() function.
138    
139     6. The escape sequence \n was being treated as whatever was defined as
140        "newline". Not only was this contrary to the documentation, which states
141        that \n is character 10 (hex 0A), but it also went horribly wrong when
142        "newline" was defined as CRLF. This has been fixed.
143    
144     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
145        was being set to -1 for the "end of line" case (supposedly a value that no
146        character can have). Though this value is never used (the check for end of
147        line is "zero bytes in current character"), it caused compiler complaints.
148        I've changed it to 0xffffffff.
149    
150     8. In pcre_version.c, the version string was being built by a sequence of
151        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
152        string (as it is for production releases) called a macro with an empty
153        argument. The C standard says the result of this is undefined. The gcc
154        compiler treats it as an empty string (which was what was wanted) but it is
155        reported that Visual C gives an error. The source has been hacked around to
156        avoid this problem.
157    
158     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
159        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
160        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
161        of them did).
162    
163    10. Originally, pcretest opened its input and output without "b"; then I was
164        told that "b" was needed in some environments, so it was added for release
165        5.0 to both the input and output. (It makes no difference on Unix-like
166        systems.) Later I was told that it is wrong for the input on Windows. I've
167        now abstracted the modes into two macros, to make it easier to fiddle with
168        them, and removed "b" from the input mode under Windows.
169    
170    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
171    
172    12. Added -help and --help to pcretest as an official way of being reminded
173        of the options.
174    
175    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
176        and pcrecpp.cc because they annoy compilers at high warning levels.
177    
178    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
179    
180    15. Fixed an occurrence of == in configure.ac that should have been = (shell
181        scripts are not C programs :-) and which was not noticed because it works
182        on Linux.
183    
184    16. pcretest is supposed to handle any length of pattern and data line (as one
185        line or as a continued sequence of lines) by extending its input buffer if
186        necessary. This feature was broken for very long pattern lines, leading to
187        a string of junk being passed to pcre_compile() if the pattern was longer
188        than about 50K.
189    
190    17. I have done a major re-factoring of the way pcre_compile() computes the
191        amount of memory needed for a compiled pattern. Previously, there was code
192        that made a preliminary scan of the pattern in order to do this. That was
193        OK when PCRE was new, but as the facilities have expanded, it has become
194        harder and harder to keep it in step with the real compile phase, and there
195        have been a number of bugs (see for example, 4 above). I have now found a
196        cunning way of running the real compile function in a "fake" mode that
197        enables it to compute how much memory it would need, while actually only
198        ever using a few hundred bytes of working memory and without too many
199        tests of the mode. This should make future maintenance and development
200        easier. A side effect of this work is that the limit of 200 on the nesting
201        depth of parentheses has been removed (though this was never a serious
202        limitation, I suspect). However, there is a downside: pcre_compile() now
203        runs more slowly than before (30% or more, depending on the pattern). I
204        hope this isn't a big issue. There is no effect on runtime performance.
205    
206    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
207        newline (only possible for the last line of a file) and it was a
208        pattern that set a locale (followed by /Lsomething), pcretest crashed.
209    
210    19. Added additional timing features to pcretest. (1) The -tm option now times
211        matching only, not compiling. (2) Both -t and -tm can be followed, as a
212        separate command line item, by a number that specifies the number of
213        repeats to use when timing. The default is 50000; this gives better
214        precision, but takes uncomfortably long for very large patterns.
215    
216    20. Extended pcre_study() to be more clever in cases where a branch of a
217        subpattern has no definite first character. For example, (a*|b*)[cd] would
218        previously give no result from pcre_study(). Now it recognizes that the
219        first character must be a, b, c, or d.
220    
221    21. There was an incorrect error "recursive call could loop indefinitely" if
222        a subpattern (or the entire pattern) that was being tested for matching an
223        empty string contained only one non-empty item after a nested subpattern.
224        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
225        incorrectly, because the \d was being skipped in the check.
226    
227    22. The pcretest program now has a new pattern option /B and a command line
228        option -b, which is equivalent to adding /B to every pattern. This causes
229        it to show the compiled bytecode, without the additional information that
230        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
231        is the same as /B/I).
232    
233    23. A new optimization is now able automatically to treat some sequences such
234        as a*b as a*+b. More specifically, if something simple (such as a character
235        or a simple class like \d) has an unlimited quantifier, and is followed by
236        something that cannot possibly match the quantified thing, the quantifier
237        is automatically "possessified".
238    
239    24. A recursive reference to a subpattern whose number was greater than 39
240        went wrong under certain circumstances in UTF-8 mode. This bug could also
241        have affected the operation of pcre_study().
242    
243    25. Realized that a little bit of performance could be had by replacing
244        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
245    
246    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
247    
248    27. Possessive quantifiers such as a++ were previously implemented by turning
249        them into atomic groups such as ($>a+). Now they have their own opcodes,
250        which improves performance. This includes the automatically created ones
251        from 23 above.
252    
253    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
254        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
255        the first matched character to be a colon. This applied both to named and
256        numbered groups.
257    
258    29. The ucpinternal.h header file was missing its idempotency #ifdef.
259    
260    30. I was sent a "project" file called libpcre.a.dev which I understand makes
261        building PCRE on Windows easier, so I have included it in the distribution.
262    
263    31. There is now a check in pcretest against a ridiculously large number being
264        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
265        loop, the loop is abandoned.
266    
267    32. Forward references to subpatterns in conditions such as (?(2)...) where
268        subpattern 2 is defined later cause pcre_compile() to search forwards in
269        the pattern for the relevant set of parentheses. This search went wrong
270        when there were unescaped parentheses in a character class, parentheses
271        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
272    
273    33. "Subroutine" calls and backreferences were previously restricted to
274        referencing subpatterns earlier in the regex. This restriction has now
275        been removed.
276    
277    34. Added a number of extra features that are going to be in Perl 5.10. On the
278        whole, these are just syntactic alternatives for features that PCRE had
279        previously implemented using the Python syntax or my own invention. The
280        other formats are all retained for compatibility.
281    
282        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
283            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
284            also .NET compatible.
285    
286        (b) A recursion or subroutine call to a named group can now be defined as
287            (?&name) as well as (?P>name).
288    
289        (c) A backreference to a named group can now be defined as \k<name> or
290            \k'name' as well as (?P=name). The new forms, as well as being in Perl
291            5.10, are also .NET compatible.
292    
293        (d) A conditional reference to a named group can now use the syntax
294            (?(<name>) or (?('name') as well as (?(name).
295    
296        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
297            groups (named and numbered) that are never evaluated inline, but can be
298            called as "subroutines" from elsewhere. In effect, the DEFINE condition
299            is always false. There may be only one alternative in such a group.
300    
301        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
302            as the simple (?(R). The condition is true only if the most recent
303            recursion is that of the given number or name. It does not search out
304            through the entire recursion stack.
305    
306        (g) The escape \gN or \g{N} has been added, where N is a positive or
307            negative number, specifying an absolute or relative reference.
308    
309    35. Tidied to get rid of some further signed/unsigned compiler warnings and
310        some "unreachable code" warnings.
311    
312    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
313        things, this adds five new scripts.
314    
315    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
316        There were also incompatibilities regarding the handling of \Q..\E inside
317        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
318        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
319    
320    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
321        matches an empty string, and forcibly breaks the loop. There were bugs in
322        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
323        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
324        separate and independent bugs (that affected different cases) have been
325        fixed.
326    
327    39. Refactored the code to abolish the use of different opcodes for small
328        capturing bracket numbers. This is a tidy that I avoided doing when I
329        removed the limit on the number of capturing brackets for 3.5 back in 2001.
330        The new approach is not only tidier, it makes it possible to reduce the
331        memory needed to fix the previous bug (38).
332    
333    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
334        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
335        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
336        mode.
337    
338    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
339        report.
340    
341    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
342        copy construction and assignment in the C++ wrapper.
343    
344    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
345        couple of bugs that could have given wrong results in the "--newline=crlf"
346        case.
347    
348    44. Added a number of casts and did some reorganization of signed/unsigned int
349        variables following suggestions from Dair Grant. Also renamed the variable
350        "this" as "item" because it is a C++ keyword.
351    
352    45. Arranged for dftables to add
353    
354          #include "pcre_internal.h"
355    
356        to pcre_chartables.c because without it, gcc 4.x may remove the array
357        definition from the final binary if PCRE is built into a static library and
358        dead code stripping is activated.
359    
360    46. For an unanchored pattern, if a match attempt fails at the start of a
361        newline sequence, and the newline setting is CRLF or ANY, and the next two
362        characters are CRLF, advance by two characters instead of one.
363    
364    
365    Version 6.7 04-Jul-06
366    ---------------------
367    
368     1. In order to handle tests when input lines are enormously long, pcretest has
369        been re-factored so that it automatically extends its buffers when
370        necessary. The code is crude, but this _is_ just a test program. The
371        default size has been increased from 32K to 50K.
372    
373     2. The code in pcre_study() was using the value of the re argument before
374        testing it for NULL. (Of course, in any sensible call of the function, it
375        won't be NULL.)
376    
377     3. The memmove() emulation function in pcre_internal.h, which is used on
378        systems that lack both memmove() and bcopy() - that is, hardly ever -
379        was missing a "static" storage class specifier.
380    
381     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
382        containing an extended class (one that cannot be represented by a bitmap
383        because it contains high-valued characters or Unicode property items, e.g.
384        [\pZ]). Almost always one would set UTF-8 mode when processing such a
385        pattern, but PCRE should not loop if you do not (it no longer does).
386        [Detail: two cases were found: (a) a repeated subpattern containing an
387        extended class; (b) a recursive reference to a subpattern that followed a
388        previous extended class. It wasn't skipping over the extended class
389        correctly when UTF-8 mode was not set.]
390    
391     5. A negated single-character class was not being recognized as fixed-length
392        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
393        compile error "lookbehind assertion is not fixed length".
394    
395     6. The RunPerlTest auxiliary script was showing an unexpected difference
396        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
397        write a Perl script that can interpret lines of an input file either as
398        byte characters or as UTF-8, which is what "perltest" was being required to
399        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
400        can't do is switch easily at run time between having the "use utf8;" pragma
401        or not. In the end, I fudged it by using the RunPerlTest script to insert
402        "use utf8;" explicitly for the UTF-8 tests.
403    
404     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
405        the end of the subject string, contrary to the documentation and to what
406        Perl does. This was true of both matching functions. Now it matches only at
407        the start of the subject and immediately after *internal* newlines.
408    
409     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
410        a pointer to an int instead of a pointer to an unsigned long int. This
411        caused problems on 64-bit systems.
412    
413     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
414        instance of the 'standard' template library not being so standard".
415    
416    10. There was no check on the number of named subpatterns nor the maximum
417        length of a subpattern name. The product of these values is used to compute
418        the size of the memory block for a compiled pattern. By supplying a very
419        long subpattern name and a large number of named subpatterns, the size
420        computation could be caused to overflow. This is now prevented by limiting
421        the length of names to 32 characters, and the number of named subpatterns
422        to 10,000.
423    
424    11. Subpatterns that are repeated with specific counts have to be replicated in
425        the compiled pattern. The size of memory for this was computed from the
426        length of the subpattern and the repeat count. The latter is limited to
427        65535, but there was no limit on the former, meaning that integer overflow
428        could in principle occur. The compiled length of a repeated subpattern is
429        now limited to 30,000 bytes in order to prevent this.
430    
431    12. Added the optional facility to have named substrings with the same name.
432    
433    13. Added the ability to use a named substring as a condition, using the
434        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
435        are numbers (not recommended). Forward references are permitted.
436    
437    14. Added forward references in named backreferences (if you see what I mean).
438    
439    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
440        pattern could run off the end of the subject. For example, the pattern
441        "(?s)(.{1,5})"8 did this with the subject "ab".
442    
443    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
444        PCRE_CASELESS was set when matching characters that were quantified with ?
445        or *.
446    
447    17. A character class other than a single negated character that had a minimum
448        but no maximum quantifier - for example [ab]{6,} - was not handled
449        correctly by pce_dfa_exec(). It would match only one character.
450    
451    18. A valid (though odd) pattern that looked like a POSIX character
452        class but used an invalid character after [ (for example [[,abc,]]) caused
453        pcre_compile() to give the error "Failed: internal error: code overflow" or
454        in some cases to crash with a glibc free() error. This could even happen if
455        the pattern terminated after [[ but there just happened to be a sequence of
456        letters, a binary zero, and a closing ] in the memory that followed.
457    
458    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
459        over the years. Originally (before any Unicode support), just the bottom 8
460        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
461        output from "man perlunicode" includes this:
462    
463          The regular expression compiler produces polymorphic opcodes.  That
464          is, the pattern adapts to the data and automatically switches to
465          the Unicode character scheme when presented with Unicode data--or
466          instead uses a traditional byte scheme when presented with byte
467          data.
468    
469        Sadly, a wide octal escape does not cause a switch, and in a string with
470        no other multibyte characters, these octal escapes are treated as before.
471        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
472        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
473        Unicode string.
474    
475        I have not perpetrated such confusion in PCRE. Up till now, it took just
476        the bottom 8 bits, as in old Perl. I have now made octal escapes with
477        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
478        translate to the appropriate multibyte character.
479    
480    29. Applied some refactoring to reduce the number of warnings from Microsoft
481        and Borland compilers. This has included removing the fudge introduced
482        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
483        a warning about an unused variable.
484    
485    21. PCRE has not included VT (character 0x0b) in the set of whitespace
486        characters since release 4.0, because Perl (from release 5.004) does not.
487        [Or at least, is documented not to: some releases seem to be in conflict
488        with the documentation.] However, when a pattern was studied with
489        pcre_study() and all its branches started with \s, PCRE still included VT
490        as a possible starting character. Of course, this did no harm; it just
491        caused an unnecessary match attempt.
492    
493    22. Removed a now-redundant internal flag bit that recorded the fact that case
494        dependency changed within the pattern. This was once needed for "required
495        byte" processing, but is no longer used. This recovers a now-scarce options
496        bit. Also moved the least significant internal flag bit to the most-
497        significant bit of the word, which was not previously used (hangover from
498        the days when it was an int rather than a uint) to free up another bit for
499        the future.
500    
501    23. Added support for CRLF line endings as well as CR and LF. As well as the
502        default being selectable at build time, it can now be changed at runtime
503        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
504        specify that it is scanning data with non-default line endings.
505    
506    24. Changed the definition of CXXLINK to make it agree with the definition of
507        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
508    
509    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
510        recursions. This makes a big different to stack usage for some patterns.
511    
512    26. If a subpattern containing a named recursion or subroutine reference such
513        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
514        the space required for the compiled pattern went wrong and gave too small a
515        value. Depending on the environment, this could lead to "Failed: internal
516        error: code overflow at offset 49" or "glibc detected double free or
517        corruption" errors.
518    
519    27. Applied patches from Google (a) to support the new newline modes and (b) to
520        advance over multibyte UTF-8 characters in GlobalReplace.
521    
522    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
523        difference for some implementation of PCRE in some Windows version.
524    
525    29. Added some extra testing facilities to pcretest:
526    
527        \q<number>   in a data line sets the "match limit" value
528        \Q<number>   in a data line sets the "match recursion limt" value
529        -S <number>  sets the stack size, where <number> is in megabytes
530    
531        The -S option isn't available for Windows.
532    
533    
534    Version 6.6 06-Feb-06
535    ---------------------
536    
537     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
538        in pcreposix.h. I have copied the definition from pcre.h.
539    
540     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
541        because pcre.h is no longer a built file.
542    
543     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
544        not normally included in the compiled code.
545    
546    
547    Version 6.5 01-Feb-06
548    ---------------------
549    
550     1. When using the partial match feature with pcre_dfa_exec(), it was not
551        anchoring the second and subsequent partial matches at the new starting
552        point. This could lead to incorrect results. For example, with the pattern
553        /1234/, partially matching against "123" and then "a4" gave a match.
554    
555     2. Changes to pcregrep:
556    
557        (a) All non-match returns from pcre_exec() were being treated as failures
558            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
559            error message is output. Some extra information is given for the
560            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
561            probably the only errors that are likely to be caused by users (by
562            specifying a regex that has nested indefinite repeats, for instance).
563            If there are more than 20 of these errors, pcregrep is abandoned.
564    
565        (b) A binary zero was treated as data while matching, but terminated the
566            output line if it was written out. This has been fixed: binary zeroes
567            are now no different to any other data bytes.
568    
569        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
570            used to set a locale for matching. The --locale=xxxx long option has
571            been added (no short equivalent) to specify a locale explicitly on the
572            pcregrep command, overriding the environment variables.
573    
574        (d) When -B was used with -n, some line numbers in the output were one less
575            than they should have been.
576    
577        (e) Added the -o (--only-matching) option.
578    
579        (f) If -A or -C was used with -c (count only), some lines of context were
580            accidentally printed for the final match.
581    
582        (g) Added the -H (--with-filename) option.
583    
584        (h) The combination of options -rh failed to suppress file names for files
585            that were found from directory arguments.
586    
587        (i) Added the -D (--devices) and -d (--directories) options.
588    
589        (j) Added the -F (--fixed-strings) option.
590    
591        (k) Allow "-" to be used as a file name for -f as well as for a data file.
592    
593        (l) Added the --colo(u)r option.
594    
595        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
596            is not present by default.
597    
598     3. A nasty bug was discovered in the handling of recursive patterns, that is,
599        items such as (?R) or (?1), when the recursion could match a number of
600        alternatives. If it matched one of the alternatives, but subsequently,
601        outside the recursion, there was a failure, the code tried to back up into
602        the recursion. However, because of the way PCRE is implemented, this is not
603        possible, and the result was an incorrect result from the match.
604    
605        In order to prevent this happening, the specification of recursion has
606        been changed so that all such subpatterns are automatically treated as
607        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
608    
609     4. I had overlooked the fact that, in some locales, there are characters for
610        which isalpha() is true but neither isupper() nor islower() are true. In
611        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
612        and ordfeminine) are like this. This affected the treatment of \w and \W
613        when they appeared in character classes, but not when they appeared outside
614        a character class. The bit map for "word" characters is now created
615        separately from the results of isalnum() instead of just taking it from the
616        upper, lower, and digit maps. (Plus the underscore character, of course.)
617    
618     5. The above bug also affected the handling of POSIX character classes such as
619        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
620        permanent tables. Instead, the bit maps for such a class were previously
621        created as the appropriate unions of the upper, lower, and digit bitmaps.
622        Now they are created by subtraction from the [[:word:]] class, which has
623        its own bitmap.
624    
625     6. The [[:blank:]] character class matches horizontal, but not vertical space.
626        It is created by subtracting the vertical space characters (\x09, \x0a,
627        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
628        subtraction was done in the overall bitmap for a character class, meaning
629        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
630        be recognized. This bug has been fixed.
631    
632     7. Patches from the folks at Google:
633    
634          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
635          real life, but is still worth protecting against".
636    
637          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
638          regular expressions".
639    
640          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
641          have it.
642    
643          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
644          "configure" and the latter not, in order to fix a problem somebody had
645          with compiling the Arg class on HP-UX.
646    
647          (e) Improve the error-handling of the C++ wrapper a little bit.
648    
649          (f) New tests for checking recursion limiting.
650    
651     8. The pcre_memmove() function, which is used only if the environment does not
652        have a standard memmove() function (and is therefore rarely compiled),
653        contained two bugs: (a) use of int instead of size_t, and (b) it was not
654        returning a result (though PCRE never actually uses the result).
655    
656     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
657        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
658        returned instead of calling malloc() with an overflowing number that would
659        most likely cause subsequent chaos.
660    
661    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
662    
663    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
664        with this option is matched, the nmatch and pmatch options of regexec() are
665        ignored.
666    
667    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
668        provided in case anyone wants to the the POSIX interface with UTF-8
669        strings.
670    
671    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
672        C++ linking (needed for some HP-UX environments).
673    
674    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
675        (unused parameter) and in the pcre_printint() function (omitted "default"
676        switch label when the default is to do nothing).
677    
678    15. Added some code to make it possible, when PCRE is compiled as a C++
679        library, to replace subject pointers for pcre_exec() with a smart pointer
680        class, thus making it possible to process discontinuous strings.
681    
682    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
683        much the same function. They were added by different people who were trying
684        to make PCRE easy to compile on non-Unix systems. It has been suggested
685        that PCRE_EXPORT be abolished now that there is more automatic apparatus
686        for compiling on Windows systems. I have therefore replaced it with
687        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
688        defaults to "extern" for C or "extern C" for C++, which works fine on
689        Unix-like systems. It is now possible to override the value of PCRE_DATA_
690        SCOPE with something explicit in config.h. In addition:
691    
692        (a) pcreposix.h still had just "extern" instead of either of these macros;
693            I have replaced it with PCRE_DATA_SCOPE.
694    
695        (b) Functions such as _pcre_xclass(), which are internal to the library,
696            but external in the C sense, all had PCRE_EXPORT in their definitions.
697            This is apparently wrong for the Windows case, so I have removed it.
698            (It makes no difference on Unix-like systems.)
699    
700    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
701        of recursive calls to match(). This is different to MATCH_LIMIT because
702        that limits the total number of calls to match(), not all of which increase
703        the depth of recursion. Limiting the recursion depth limits the amount of
704        stack (or heap if NO_RECURSE is set) that is used. The default can be set
705        when PCRE is compiled, and changed at run time. A patch from Google adds
706        this functionality to the C++ interface.
707    
708    18. Changes to the handling of Unicode character properties:
709    
710        (a) Updated the table to Unicode 4.1.0.
711    
712        (b) Recognize characters that are not in the table as "Cn" (undefined).
713    
714        (c) I revised the way the table is implemented to a much improved format
715            which includes recognition of ranges. It now supports the ranges that
716            are defined in UnicodeData.txt, and it also amalgamates other
717            characters into ranges. This has reduced the number of entries in the
718            table from around 16,000 to around 3,000, thus reducing its size
719            considerably. I realized I did not need to use a tree structure after
720            all - a binary chop search is just as efficient. Having reduced the
721            number of entries, I extended their size from 6 bytes to 8 bytes to
722            allow for more data.
723    
724        (d) Added support for Unicode script names via properties such as \p{Han}.
725    
726    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
727        matching that character.
728    
729    20. When matching a repeated Unicode property with a minimum greater than zero,
730        (for example \pL{2,}), PCRE could look past the end of the subject if it
731        reached it while seeking the minimum number of characters. This could
732        happen only if some of the characters were more than one byte long, because
733        there is a check for at least the minimum number of bytes.
734    
735    21. Refactored the implementation of \p and \P so as to be more general, to
736        allow for more different types of property in future. This has changed the
737        compiled form incompatibly. Anybody with saved compiled patterns that use
738        \p or \P will have to recompile them.
739    
740    22. Added "Any" and "L&" to the supported property types.
741    
742    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
743        but give a compile time error if the value is greater than 0xff.
744    
745    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
746        accidentally not being installed or uninstalled.
747    
748    25. The pcre.h file was built from pcre.h.in, but the only changes that were
749        made were to insert the current release number. This seemed silly, because
750        it made things harder for people building PCRE on systems that don't run
751        "configure". I have turned pcre.h into a distributed file, no longer built
752        by "configure", with the version identification directly included. There is
753        no longer a pcre.h.in file.
754    
755        However, this change necessitated a change to the pcre-config script as
756        well. It is built from pcre-config.in, and one of the substitutions was the
757        release number. I have updated configure.ac so that ./configure now finds
758        the release number by grepping pcre.h.
759    
760    26. Added the ability to run the tests under valgrind.
761    
762    
763    Version 6.4 05-Sep-05
764    ---------------------
765    
766     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
767        "--" to be printed when multiple files were scanned, even when none of the
768        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
769        consider it to be a bug, and have restored the previous behaviour.
770    
771     2. A couple of code tidies to get rid of compiler warnings.
772    
773     3. The pcretest program used to cheat by referring to symbols in the library
774        whose names begin with _pcre_. These are internal symbols that are not
775        really supposed to be visible externally, and in some environments it is
776        possible to suppress them. The cheating is now confined to including
777        certain files from the library's source, which is a bit cleaner.
778    
779     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
780        file's purpose clearer.
781    
782     5. Reorganized pcre_ucp_findchar().
783    
784    
785  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
786  ---------------------  ---------------------
787    

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