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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.2 01-May-07
5    ---------------------
7     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
8        which is apparently normally available under Windows.
10     2. Re-jig the pcregrep tests with different newline settings in an attempt
11        to make them independent of the local environment's newline setting.
14    Version 7.1 24-Apr-07
15    ---------------------
17     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
18        that is more "standard", making use of automake and other Autotools. There
19        is some re-arrangement of the files and adjustment of comments consequent
20        on this.
22     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
23        for recursive directory scanning broke on some systems because the files
24        are not scanned in any specific order and on different systems the order
25        was different. A call to "sort" has been inserted into RunGrepTest for the
26        approprate test as a short-term fix. In the longer term there may be an
27        alternative.
29     3. I had an email from Eric Raymond about problems translating some of PCRE's
30        man pages to HTML (despite the fact that I distribute HTML pages, some
31        people do their own conversions for various reasons). The problems
32        concerned the use of low-level troff macros .br and .in. I have therefore
33        removed all such uses from the man pages (some were redundant, some could
34        be replaced by .nf/.fi pairs). The 132html script that I use to generate
35        HTML has been updated to handle .nf/.fi and to complain if it encounters
36        .br or .in.
38     4. Updated comments in configure.ac that get placed in config.h.in and also
39        arranged for config.h to be included in the distribution, with the name
40        config.h.generic, for the benefit of those who have to compile without
41        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
43     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
44        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
45        makevp.bat for the current PCRE, using the additional files
46        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
48     6. A Windows user reported a minor discrepancy with test 2, which turned out
49        to be caused by a trailing space on an input line that had got lost in his
50        copy. The trailing space was an accident, so I've just removed it.
52     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
53        that is needed.
55     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
56        as "const" (a) because they are and (b) because it helps the PHP
57        maintainers who have recently made a script to detect big data structures
58        in the php code that should be moved to the .rodata section. I remembered
59        to update Builducptable as well, so it won't revert if ucptable.h is ever
60        re-created.
62     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
63        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
64        order to be able to cut out the UTF-8 tables in the latter when UTF-8
65        support is not required. This saves 1.5-2K of code, which is important in
66        some applications.
68        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
69        so as not to refer to the tables, even though these functions will never be
70        called when UTF-8 support is disabled. Otherwise there are problems with a
71        shared library.
73    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
75        (a) It was defining its arguments as char * instead of void *.
77        (b) It was assuming that all moves were upwards in memory; this was true
78            a long time ago when I wrote it, but is no longer the case.
80        The emulated memove() is provided for those environments that have neither
81        memmove() nor bcopy(). I didn't think anyone used it these days, but that
82        is clearly not the case, as these two bugs were recently reported.
84    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
85        and Detrail to create the HTML documentation, the .txt form of the man
86        pages, and it removes trailing spaces from listed files. It also creates
87        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
88        case, it wraps all the #defines with #ifndefs. This script should be run
89        before "make dist".
91    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
92        with Unicode property support.
94        (a) For a maximizing quantifier, if the two different cases of the
95            character were of different lengths in their UTF-8 codings (there are
96            some cases like this - I found 11), and the matching function had to
97            back up over a mixture of the two cases, it incorrectly assumed they
98            were both the same length.
100        (b) When PCRE was configured to use the heap rather than the stack for
101            recursion during matching, it was not correctly preserving the data for
102            the other case of a UTF-8 character when checking ahead for a match
103            while processing a minimizing repeat. If the check also involved
104            matching a wide character, but failed, corruption could cause an
105            erroneous result when trying to check for a repeat of the original
106            character.
108    13. Some tidying changes to the testing mechanism:
110        (a) The RunTest script now detects the internal link size and whether there
111            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
112            values substituted by "configure". (The RunGrepTest script already did
113            this for UTF-8.) The configure.ac script no longer substitutes the
114            relevant variables.
116        (b) The debugging options /B and /D in pcretest show the compiled bytecode
117            with length and offset values. This means that the output is different
118            for different internal link sizes. Test 2 is skipped for link sizes
119            other than 2 because of this, bypassing the problem. Unfortunately,
120            there was also a test in test 3 (the locale tests) that used /B and
121            failed for link sizes other than 2. Rather than cut the whole test out,
122            I have added a new /Z option to pcretest that replaces the length and
123            offset values with spaces. This is now used to make test 3 independent
124            of link size. (Test 2 will be tidied up later.)
126    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
127        segmentation fault instead of returning the appropriate error message.
129    15. In multiline mode when the newline sequence was set to "any", the pattern
130        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
131        This doesn't seem right; it now treats the CRLF combination as the line
132        ending, and so does not match in that case. It's only a pattern such as ^$
133        that would hit this one: something like ^ABC$ would have failed after \r
134        and then tried again after \r\n.
136    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
137        in an attempt to make files that differ only in their line terminators
138        compare equal. This works on Linux.
140    17. Under certain error circumstances pcregrep might try to free random memory
141        as it exited. This is now fixed, thanks to valgrind.
143    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
144        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
145        was because its rules for how to advance for /g after matching an empty
146        string at the end of a line did not allow for this case. They now check for
147        it specially.
149    20. pcretest is supposed to handle patterns and data of any length, by
150        extending its buffers when necessary. It was getting this wrong when the
151        buffer for a data line had to be extended.
153    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
154        CRLF as a newline sequence.
156    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
157        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
158        I have nevertheless tidied it up.
160    23. Added some casts to kill warnings from HP-UX ia64 compiler.
162    24. Added a man page for pcre-config.
165    Version 7.0 19-Dec-06
166    ---------------------
168     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
169        moving to gcc 4.1.1.
171     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
172        sys/time.h, which is documented as needed for this function. It doesn't
173        seem to matter on Linux, but it showed up on some releases of OS X.
175     3. It seems that there are systems where bytes whose values are greater than
176        127 match isprint() in the "C" locale. The "C" locale should be the
177        default when a C program starts up. In most systems, only ASCII printing
178        characters match isprint(). This difference caused the output from pcretest
179        to vary, making some of the tests fail. I have changed pcretest so that:
181        (a) When it is outputting text in the compiled version of a pattern, bytes
182            other than 32-126 are always shown as hex escapes.
184        (b) When it is outputting text that is a matched part of a subject string,
185            it does the same, unless a different locale has been set for the match
186            (using the /L modifier). In this case, it uses isprint() to decide.
188     4. Fixed a major bug that caused incorrect computation of the amount of memory
189        required for a compiled pattern when options that changed within the
190        pattern affected the logic of the preliminary scan that determines the
191        length. The relevant options are -x, and -i in UTF-8 mode. The result was
192        that the computed length was too small. The symptoms of this bug were
193        either the PCRE error "internal error: code overflow" from pcre_compile(),
194        or a glibc crash with a message such as "pcretest: free(): invalid next
195        size (fast)". Examples of patterns that provoked this bug (shown in
196        pcretest format) are:
198          /(?-x: )/x
199          /(?x)(?-x: \s*#\s*)/
200          /((?i)[\x{c0}])/8
201          /(?i:[\x{c0}])/8
203        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
204        is now done differently.
206     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
207        wrapper classes; (b) implement a new function in the C++ scanner that is
208        more efficient than the old way of doing things because it avoids levels of
209        recursion in the regex matching; (c) add a paragraph to the documentation
210        for the FullMatch() function.
212     6. The escape sequence \n was being treated as whatever was defined as
213        "newline". Not only was this contrary to the documentation, which states
214        that \n is character 10 (hex 0A), but it also went horribly wrong when
215        "newline" was defined as CRLF. This has been fixed.
217     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
218        was being set to -1 for the "end of line" case (supposedly a value that no
219        character can have). Though this value is never used (the check for end of
220        line is "zero bytes in current character"), it caused compiler complaints.
221        I've changed it to 0xffffffff.
223     8. In pcre_version.c, the version string was being built by a sequence of
224        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
225        string (as it is for production releases) called a macro with an empty
226        argument. The C standard says the result of this is undefined. The gcc
227        compiler treats it as an empty string (which was what was wanted) but it is
228        reported that Visual C gives an error. The source has been hacked around to
229        avoid this problem.
231     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
232        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
233        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
234        of them did).
236    10. Originally, pcretest opened its input and output without "b"; then I was
237        told that "b" was needed in some environments, so it was added for release
238        5.0 to both the input and output. (It makes no difference on Unix-like
239        systems.) Later I was told that it is wrong for the input on Windows. I've
240        now abstracted the modes into two macros, to make it easier to fiddle with
241        them, and removed "b" from the input mode under Windows.
243    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
245    12. Added -help and --help to pcretest as an official way of being reminded
246        of the options.
248    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
249        and pcrecpp.cc because they annoy compilers at high warning levels.
251    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
253    15. Fixed an occurrence of == in configure.ac that should have been = (shell
254        scripts are not C programs :-) and which was not noticed because it works
255        on Linux.
257    16. pcretest is supposed to handle any length of pattern and data line (as one
258        line or as a continued sequence of lines) by extending its input buffer if
259        necessary. This feature was broken for very long pattern lines, leading to
260        a string of junk being passed to pcre_compile() if the pattern was longer
261        than about 50K.
263    17. I have done a major re-factoring of the way pcre_compile() computes the
264        amount of memory needed for a compiled pattern. Previously, there was code
265        that made a preliminary scan of the pattern in order to do this. That was
266        OK when PCRE was new, but as the facilities have expanded, it has become
267        harder and harder to keep it in step with the real compile phase, and there
268        have been a number of bugs (see for example, 4 above). I have now found a
269        cunning way of running the real compile function in a "fake" mode that
270        enables it to compute how much memory it would need, while actually only
271        ever using a few hundred bytes of working memory and without too many
272        tests of the mode. This should make future maintenance and development
273        easier. A side effect of this work is that the limit of 200 on the nesting
274        depth of parentheses has been removed (though this was never a serious
275        limitation, I suspect). However, there is a downside: pcre_compile() now
276        runs more slowly than before (30% or more, depending on the pattern). I
277        hope this isn't a big issue. There is no effect on runtime performance.
279    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
280        newline (only possible for the last line of a file) and it was a
281        pattern that set a locale (followed by /Lsomething), pcretest crashed.
283    19. Added additional timing features to pcretest. (1) The -tm option now times
284        matching only, not compiling. (2) Both -t and -tm can be followed, as a
285        separate command line item, by a number that specifies the number of
286        repeats to use when timing. The default is 50000; this gives better
287        precision, but takes uncomfortably long for very large patterns.
289    20. Extended pcre_study() to be more clever in cases where a branch of a
290        subpattern has no definite first character. For example, (a*|b*)[cd] would
291        previously give no result from pcre_study(). Now it recognizes that the
292        first character must be a, b, c, or d.
294    21. There was an incorrect error "recursive call could loop indefinitely" if
295        a subpattern (or the entire pattern) that was being tested for matching an
296        empty string contained only one non-empty item after a nested subpattern.
297        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
298        incorrectly, because the \d was being skipped in the check.
300    22. The pcretest program now has a new pattern option /B and a command line
301        option -b, which is equivalent to adding /B to every pattern. This causes
302        it to show the compiled bytecode, without the additional information that
303        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
304        is the same as /B/I).
306    23. A new optimization is now able automatically to treat some sequences such
307        as a*b as a*+b. More specifically, if something simple (such as a character
308        or a simple class like \d) has an unlimited quantifier, and is followed by
309        something that cannot possibly match the quantified thing, the quantifier
310        is automatically "possessified".
312    24. A recursive reference to a subpattern whose number was greater than 39
313        went wrong under certain circumstances in UTF-8 mode. This bug could also
314        have affected the operation of pcre_study().
316    25. Realized that a little bit of performance could be had by replacing
317        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
319    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
321    27. Possessive quantifiers such as a++ were previously implemented by turning
322        them into atomic groups such as ($>a+). Now they have their own opcodes,
323        which improves performance. This includes the automatically created ones
324        from 23 above.
326    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
327        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
328        the first matched character to be a colon. This applied both to named and
329        numbered groups.
331    29. The ucpinternal.h header file was missing its idempotency #ifdef.
333    30. I was sent a "project" file called libpcre.a.dev which I understand makes
334        building PCRE on Windows easier, so I have included it in the distribution.
336    31. There is now a check in pcretest against a ridiculously large number being
337        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
338        loop, the loop is abandoned.
340    32. Forward references to subpatterns in conditions such as (?(2)...) where
341        subpattern 2 is defined later cause pcre_compile() to search forwards in
342        the pattern for the relevant set of parentheses. This search went wrong
343        when there were unescaped parentheses in a character class, parentheses
344        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
346    33. "Subroutine" calls and backreferences were previously restricted to
347        referencing subpatterns earlier in the regex. This restriction has now
348        been removed.
350    34. Added a number of extra features that are going to be in Perl 5.10. On the
351        whole, these are just syntactic alternatives for features that PCRE had
352        previously implemented using the Python syntax or my own invention. The
353        other formats are all retained for compatibility.
355        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
356            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
357            also .NET compatible.
359        (b) A recursion or subroutine call to a named group can now be defined as
360            (?&name) as well as (?P>name).
362        (c) A backreference to a named group can now be defined as \k<name> or
363            \k'name' as well as (?P=name). The new forms, as well as being in Perl
364            5.10, are also .NET compatible.
366        (d) A conditional reference to a named group can now use the syntax
367            (?(<name>) or (?('name') as well as (?(name).
369        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
370            groups (named and numbered) that are never evaluated inline, but can be
371            called as "subroutines" from elsewhere. In effect, the DEFINE condition
372            is always false. There may be only one alternative in such a group.
374        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
375            as the simple (?(R). The condition is true only if the most recent
376            recursion is that of the given number or name. It does not search out
377            through the entire recursion stack.
379        (g) The escape \gN or \g{N} has been added, where N is a positive or
380            negative number, specifying an absolute or relative reference.
382    35. Tidied to get rid of some further signed/unsigned compiler warnings and
383        some "unreachable code" warnings.
385    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
386        things, this adds five new scripts.
388    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
389        There were also incompatibilities regarding the handling of \Q..\E inside
390        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
391        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
393    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
394        matches an empty string, and forcibly breaks the loop. There were bugs in
395        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
396        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
397        separate and independent bugs (that affected different cases) have been
398        fixed.
400    39. Refactored the code to abolish the use of different opcodes for small
401        capturing bracket numbers. This is a tidy that I avoided doing when I
402        removed the limit on the number of capturing brackets for 3.5 back in 2001.
403        The new approach is not only tidier, it makes it possible to reduce the
404        memory needed to fix the previous bug (38).
406    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
407        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
408        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
409        mode.
411    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
412        report.
414    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
415        copy construction and assignment in the C++ wrapper.
417    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
418        couple of bugs that could have given wrong results in the "--newline=crlf"
419        case.
421    44. Added a number of casts and did some reorganization of signed/unsigned int
422        variables following suggestions from Dair Grant. Also renamed the variable
423        "this" as "item" because it is a C++ keyword.
425    45. Arranged for dftables to add
427          #include "pcre_internal.h"
429        to pcre_chartables.c because without it, gcc 4.x may remove the array
430        definition from the final binary if PCRE is built into a static library and
431        dead code stripping is activated.
433    46. For an unanchored pattern, if a match attempt fails at the start of a
434        newline sequence, and the newline setting is CRLF or ANY, and the next two
435        characters are CRLF, advance by two characters instead of one.
438    Version 6.7 04-Jul-06
439    ---------------------
441     1. In order to handle tests when input lines are enormously long, pcretest has
442        been re-factored so that it automatically extends its buffers when
443        necessary. The code is crude, but this _is_ just a test program. The
444        default size has been increased from 32K to 50K.
446     2. The code in pcre_study() was using the value of the re argument before
447        testing it for NULL. (Of course, in any sensible call of the function, it
448        won't be NULL.)
450     3. The memmove() emulation function in pcre_internal.h, which is used on
451        systems that lack both memmove() and bcopy() - that is, hardly ever -
452        was missing a "static" storage class specifier.
454     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
455        containing an extended class (one that cannot be represented by a bitmap
456        because it contains high-valued characters or Unicode property items, e.g.
457        [\pZ]). Almost always one would set UTF-8 mode when processing such a
458        pattern, but PCRE should not loop if you do not (it no longer does).
459        [Detail: two cases were found: (a) a repeated subpattern containing an
460        extended class; (b) a recursive reference to a subpattern that followed a
461        previous extended class. It wasn't skipping over the extended class
462        correctly when UTF-8 mode was not set.]
464     5. A negated single-character class was not being recognized as fixed-length
465        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
466        compile error "lookbehind assertion is not fixed length".
468     6. The RunPerlTest auxiliary script was showing an unexpected difference
469        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
470        write a Perl script that can interpret lines of an input file either as
471        byte characters or as UTF-8, which is what "perltest" was being required to
472        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
473        can't do is switch easily at run time between having the "use utf8;" pragma
474        or not. In the end, I fudged it by using the RunPerlTest script to insert
475        "use utf8;" explicitly for the UTF-8 tests.
477     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
478        the end of the subject string, contrary to the documentation and to what
479        Perl does. This was true of both matching functions. Now it matches only at
480        the start of the subject and immediately after *internal* newlines.
482     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
483        a pointer to an int instead of a pointer to an unsigned long int. This
484        caused problems on 64-bit systems.
486     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
487        instance of the 'standard' template library not being so standard".
489    10. There was no check on the number of named subpatterns nor the maximum
490        length of a subpattern name. The product of these values is used to compute
491        the size of the memory block for a compiled pattern. By supplying a very
492        long subpattern name and a large number of named subpatterns, the size
493        computation could be caused to overflow. This is now prevented by limiting
494        the length of names to 32 characters, and the number of named subpatterns
495        to 10,000.
497    11. Subpatterns that are repeated with specific counts have to be replicated in
498        the compiled pattern. The size of memory for this was computed from the
499        length of the subpattern and the repeat count. The latter is limited to
500        65535, but there was no limit on the former, meaning that integer overflow
501        could in principle occur. The compiled length of a repeated subpattern is
502        now limited to 30,000 bytes in order to prevent this.
504    12. Added the optional facility to have named substrings with the same name.
506    13. Added the ability to use a named substring as a condition, using the
507        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
508        are numbers (not recommended). Forward references are permitted.
510    14. Added forward references in named backreferences (if you see what I mean).
512    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
513        pattern could run off the end of the subject. For example, the pattern
514        "(?s)(.{1,5})"8 did this with the subject "ab".
516    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
517        PCRE_CASELESS was set when matching characters that were quantified with ?
518        or *.
520    17. A character class other than a single negated character that had a minimum
521        but no maximum quantifier - for example [ab]{6,} - was not handled
522        correctly by pce_dfa_exec(). It would match only one character.
524    18. A valid (though odd) pattern that looked like a POSIX character
525        class but used an invalid character after [ (for example [[,abc,]]) caused
526        pcre_compile() to give the error "Failed: internal error: code overflow" or
527        in some cases to crash with a glibc free() error. This could even happen if
528        the pattern terminated after [[ but there just happened to be a sequence of
529        letters, a binary zero, and a closing ] in the memory that followed.
531    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
532        over the years. Originally (before any Unicode support), just the bottom 8
533        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
534        output from "man perlunicode" includes this:
536          The regular expression compiler produces polymorphic opcodes.  That
537          is, the pattern adapts to the data and automatically switches to
538          the Unicode character scheme when presented with Unicode data--or
539          instead uses a traditional byte scheme when presented with byte
540          data.
542        Sadly, a wide octal escape does not cause a switch, and in a string with
543        no other multibyte characters, these octal escapes are treated as before.
544        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
545        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
546        Unicode string.
548        I have not perpetrated such confusion in PCRE. Up till now, it took just
549        the bottom 8 bits, as in old Perl. I have now made octal escapes with
550        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
551        translate to the appropriate multibyte character.
553    29. Applied some refactoring to reduce the number of warnings from Microsoft
554        and Borland compilers. This has included removing the fudge introduced
555        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
556        a warning about an unused variable.
558    21. PCRE has not included VT (character 0x0b) in the set of whitespace
559        characters since release 4.0, because Perl (from release 5.004) does not.
560        [Or at least, is documented not to: some releases seem to be in conflict
561        with the documentation.] However, when a pattern was studied with
562        pcre_study() and all its branches started with \s, PCRE still included VT
563        as a possible starting character. Of course, this did no harm; it just
564        caused an unnecessary match attempt.
566    22. Removed a now-redundant internal flag bit that recorded the fact that case
567        dependency changed within the pattern. This was once needed for "required
568        byte" processing, but is no longer used. This recovers a now-scarce options
569        bit. Also moved the least significant internal flag bit to the most-
570        significant bit of the word, which was not previously used (hangover from
571        the days when it was an int rather than a uint) to free up another bit for
572        the future.
574    23. Added support for CRLF line endings as well as CR and LF. As well as the
575        default being selectable at build time, it can now be changed at runtime
576        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
577        specify that it is scanning data with non-default line endings.
579    24. Changed the definition of CXXLINK to make it agree with the definition of
580        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
582    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
583        recursions. This makes a big different to stack usage for some patterns.
585    26. If a subpattern containing a named recursion or subroutine reference such
586        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
587        the space required for the compiled pattern went wrong and gave too small a
588        value. Depending on the environment, this could lead to "Failed: internal
589        error: code overflow at offset 49" or "glibc detected double free or
590        corruption" errors.
592    27. Applied patches from Google (a) to support the new newline modes and (b) to
593        advance over multibyte UTF-8 characters in GlobalReplace.
595    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
596        difference for some implementation of PCRE in some Windows version.
598    29. Added some extra testing facilities to pcretest:
600        \q<number>   in a data line sets the "match limit" value
601        \Q<number>   in a data line sets the "match recursion limt" value
602        -S <number>  sets the stack size, where <number> is in megabytes
604        The -S option isn't available for Windows.
607  Version 6.6 06-Feb-06  Version 6.6 06-Feb-06
608  ---------------------  ---------------------

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