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

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