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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.2 05-June-07
5    ---------------------
6    
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.
9    
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.
12    
13     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
14    
15     4. Some of the "internals" tests were previously cut out when the link size
16        was not 2, because the output contained actual offsets. The recent new
17        "Z" feature of pcretest means that these can be cut out, making the tests
18        usable with all link sizes.
19    
20     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
21        stack recursion. This gives a massive performance boost under BSD, but just
22        a small improvement under Linux. However, it saves one field in the frame
23        in all cases.
24    
25     6. Added more features from the forthcoming Perl 5.10:
26    
27        (a) (?-n) (where n is a string of digits) is a relative subroutine or
28            recursion call. It refers to the nth most recently opened parentheses.
29    
30        (b) (?+n) is also a relative subroutine call; it refers to the nth next
31            to be opened parentheses.
32    
33        (c) Conditions that refer to capturing parentheses can be specified
34            relatively, for example, (?(-2)... or (?(+3)...
35    
36        (d) \K resets the start of the current match so that everything before
37            is not part of it.
38    
39        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
40    
41        (f) \g{name} is another synonym - part of Perl 5.10's unification of
42            reference syntax.
43    
44        (g) (?| introduces a group in which the numbering of parentheses in each
45            alternative starts with the same number.
46    
47     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
48        PCRE_INFO_JCHANGED.
49    
50     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
51        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
52        for detecting groups that can match an empty string.
53    
54     9. A pattern with a very large number of alternatives (more than several
55        hundred) was running out of internal workspace during the pre-compile
56        phase, where pcre_compile() figures out how much memory will be needed. A
57        bit of new cunning has reduced the workspace needed for groups with
58        alternatives. The 1000-alternative test pattern now uses 12 bytes of
59        workspace instead of running out of the 4096 that are available.
60    
61    
62    Version 7.1 24-Apr-07
63    ---------------------
64    
65     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
66        that is more "standard", making use of automake and other Autotools. There
67        is some re-arrangement of the files and adjustment of comments consequent
68        on this.
69    
70     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
71        for recursive directory scanning broke on some systems because the files
72        are not scanned in any specific order and on different systems the order
73        was different. A call to "sort" has been inserted into RunGrepTest for the
74        approprate test as a short-term fix. In the longer term there may be an
75        alternative.
76    
77     3. I had an email from Eric Raymond about problems translating some of PCRE's
78        man pages to HTML (despite the fact that I distribute HTML pages, some
79        people do their own conversions for various reasons). The problems
80        concerned the use of low-level troff macros .br and .in. I have therefore
81        removed all such uses from the man pages (some were redundant, some could
82        be replaced by .nf/.fi pairs). The 132html script that I use to generate
83        HTML has been updated to handle .nf/.fi and to complain if it encounters
84        .br or .in.
85    
86     4. Updated comments in configure.ac that get placed in config.h.in and also
87        arranged for config.h to be included in the distribution, with the name
88        config.h.generic, for the benefit of those who have to compile without
89        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
90    
91     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
92        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
93        makevp.bat for the current PCRE, using the additional files
94        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
95    
96     6. A Windows user reported a minor discrepancy with test 2, which turned out
97        to be caused by a trailing space on an input line that had got lost in his
98        copy. The trailing space was an accident, so I've just removed it.
99    
100     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
101        that is needed.
102    
103     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
104        as "const" (a) because they are and (b) because it helps the PHP
105        maintainers who have recently made a script to detect big data structures
106        in the php code that should be moved to the .rodata section. I remembered
107        to update Builducptable as well, so it won't revert if ucptable.h is ever
108        re-created.
109    
110     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
111        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
112        order to be able to cut out the UTF-8 tables in the latter when UTF-8
113        support is not required. This saves 1.5-2K of code, which is important in
114        some applications.
115    
116        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
117        so as not to refer to the tables, even though these functions will never be
118        called when UTF-8 support is disabled. Otherwise there are problems with a
119        shared library.
120    
121    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
122    
123        (a) It was defining its arguments as char * instead of void *.
124    
125        (b) It was assuming that all moves were upwards in memory; this was true
126            a long time ago when I wrote it, but is no longer the case.
127    
128        The emulated memove() is provided for those environments that have neither
129        memmove() nor bcopy(). I didn't think anyone used it these days, but that
130        is clearly not the case, as these two bugs were recently reported.
131    
132    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
133        and Detrail to create the HTML documentation, the .txt form of the man
134        pages, and it removes trailing spaces from listed files. It also creates
135        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
136        case, it wraps all the #defines with #ifndefs. This script should be run
137        before "make dist".
138    
139    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
140        with Unicode property support.
141    
142        (a) For a maximizing quantifier, if the two different cases of the
143            character were of different lengths in their UTF-8 codings (there are
144            some cases like this - I found 11), and the matching function had to
145            back up over a mixture of the two cases, it incorrectly assumed they
146            were both the same length.
147    
148        (b) When PCRE was configured to use the heap rather than the stack for
149            recursion during matching, it was not correctly preserving the data for
150            the other case of a UTF-8 character when checking ahead for a match
151            while processing a minimizing repeat. If the check also involved
152            matching a wide character, but failed, corruption could cause an
153            erroneous result when trying to check for a repeat of the original
154            character.
155    
156    13. Some tidying changes to the testing mechanism:
157    
158        (a) The RunTest script now detects the internal link size and whether there
159            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
160            values substituted by "configure". (The RunGrepTest script already did
161            this for UTF-8.) The configure.ac script no longer substitutes the
162            relevant variables.
163    
164        (b) The debugging options /B and /D in pcretest show the compiled bytecode
165            with length and offset values. This means that the output is different
166            for different internal link sizes. Test 2 is skipped for link sizes
167            other than 2 because of this, bypassing the problem. Unfortunately,
168            there was also a test in test 3 (the locale tests) that used /B and
169            failed for link sizes other than 2. Rather than cut the whole test out,
170            I have added a new /Z option to pcretest that replaces the length and
171            offset values with spaces. This is now used to make test 3 independent
172            of link size. (Test 2 will be tidied up later.)
173    
174    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
175        segmentation fault instead of returning the appropriate error message.
176    
177    15. In multiline mode when the newline sequence was set to "any", the pattern
178        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
179        This doesn't seem right; it now treats the CRLF combination as the line
180        ending, and so does not match in that case. It's only a pattern such as ^$
181        that would hit this one: something like ^ABC$ would have failed after \r
182        and then tried again after \r\n.
183    
184    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
185        in an attempt to make files that differ only in their line terminators
186        compare equal. This works on Linux.
187    
188    17. Under certain error circumstances pcregrep might try to free random memory
189        as it exited. This is now fixed, thanks to valgrind.
190    
191    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
192        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
193        was because its rules for how to advance for /g after matching an empty
194        string at the end of a line did not allow for this case. They now check for
195        it specially.
196    
197    20. pcretest is supposed to handle patterns and data of any length, by
198        extending its buffers when necessary. It was getting this wrong when the
199        buffer for a data line had to be extended.
200    
201    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
202        CRLF as a newline sequence.
203    
204    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
205        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
206        I have nevertheless tidied it up.
207    
208    23. Added some casts to kill warnings from HP-UX ia64 compiler.
209    
210    24. Added a man page for pcre-config.
211    
212    
213    Version 7.0 19-Dec-06
214    ---------------------
215    
216     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
217        moving to gcc 4.1.1.
218    
219     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
220        sys/time.h, which is documented as needed for this function. It doesn't
221        seem to matter on Linux, but it showed up on some releases of OS X.
222    
223     3. It seems that there are systems where bytes whose values are greater than
224        127 match isprint() in the "C" locale. The "C" locale should be the
225        default when a C program starts up. In most systems, only ASCII printing
226        characters match isprint(). This difference caused the output from pcretest
227        to vary, making some of the tests fail. I have changed pcretest so that:
228    
229        (a) When it is outputting text in the compiled version of a pattern, bytes
230            other than 32-126 are always shown as hex escapes.
231    
232        (b) When it is outputting text that is a matched part of a subject string,
233            it does the same, unless a different locale has been set for the match
234            (using the /L modifier). In this case, it uses isprint() to decide.
235    
236     4. Fixed a major bug that caused incorrect computation of the amount of memory
237        required for a compiled pattern when options that changed within the
238        pattern affected the logic of the preliminary scan that determines the
239        length. The relevant options are -x, and -i in UTF-8 mode. The result was
240        that the computed length was too small. The symptoms of this bug were
241        either the PCRE error "internal error: code overflow" from pcre_compile(),
242        or a glibc crash with a message such as "pcretest: free(): invalid next
243        size (fast)". Examples of patterns that provoked this bug (shown in
244        pcretest format) are:
245    
246          /(?-x: )/x
247          /(?x)(?-x: \s*#\s*)/
248          /((?i)[\x{c0}])/8
249          /(?i:[\x{c0}])/8
250    
251        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
252        is now done differently.
253    
254     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
255        wrapper classes; (b) implement a new function in the C++ scanner that is
256        more efficient than the old way of doing things because it avoids levels of
257        recursion in the regex matching; (c) add a paragraph to the documentation
258        for the FullMatch() function.
259    
260     6. The escape sequence \n was being treated as whatever was defined as
261        "newline". Not only was this contrary to the documentation, which states
262        that \n is character 10 (hex 0A), but it also went horribly wrong when
263        "newline" was defined as CRLF. This has been fixed.
264    
265     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
266        was being set to -1 for the "end of line" case (supposedly a value that no
267        character can have). Though this value is never used (the check for end of
268        line is "zero bytes in current character"), it caused compiler complaints.
269        I've changed it to 0xffffffff.
270    
271     8. In pcre_version.c, the version string was being built by a sequence of
272        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
273        string (as it is for production releases) called a macro with an empty
274        argument. The C standard says the result of this is undefined. The gcc
275        compiler treats it as an empty string (which was what was wanted) but it is
276        reported that Visual C gives an error. The source has been hacked around to
277        avoid this problem.
278    
279     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
280        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
281        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
282        of them did).
283    
284    10. Originally, pcretest opened its input and output without "b"; then I was
285        told that "b" was needed in some environments, so it was added for release
286        5.0 to both the input and output. (It makes no difference on Unix-like
287        systems.) Later I was told that it is wrong for the input on Windows. I've
288        now abstracted the modes into two macros, to make it easier to fiddle with
289        them, and removed "b" from the input mode under Windows.
290    
291    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
292    
293    12. Added -help and --help to pcretest as an official way of being reminded
294        of the options.
295    
296    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
297        and pcrecpp.cc because they annoy compilers at high warning levels.
298    
299    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
300    
301    15. Fixed an occurrence of == in configure.ac that should have been = (shell
302        scripts are not C programs :-) and which was not noticed because it works
303        on Linux.
304    
305    16. pcretest is supposed to handle any length of pattern and data line (as one
306        line or as a continued sequence of lines) by extending its input buffer if
307        necessary. This feature was broken for very long pattern lines, leading to
308        a string of junk being passed to pcre_compile() if the pattern was longer
309        than about 50K.
310    
311    17. I have done a major re-factoring of the way pcre_compile() computes the
312        amount of memory needed for a compiled pattern. Previously, there was code
313        that made a preliminary scan of the pattern in order to do this. That was
314        OK when PCRE was new, but as the facilities have expanded, it has become
315        harder and harder to keep it in step with the real compile phase, and there
316        have been a number of bugs (see for example, 4 above). I have now found a
317        cunning way of running the real compile function in a "fake" mode that
318        enables it to compute how much memory it would need, while actually only
319        ever using a few hundred bytes of working memory and without too many
320        tests of the mode. This should make future maintenance and development
321        easier. A side effect of this work is that the limit of 200 on the nesting
322        depth of parentheses has been removed (though this was never a serious
323        limitation, I suspect). However, there is a downside: pcre_compile() now
324        runs more slowly than before (30% or more, depending on the pattern). I
325        hope this isn't a big issue. There is no effect on runtime performance.
326    
327    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
328        newline (only possible for the last line of a file) and it was a
329        pattern that set a locale (followed by /Lsomething), pcretest crashed.
330    
331    19. Added additional timing features to pcretest. (1) The -tm option now times
332        matching only, not compiling. (2) Both -t and -tm can be followed, as a
333        separate command line item, by a number that specifies the number of
334        repeats to use when timing. The default is 50000; this gives better
335        precision, but takes uncomfortably long for very large patterns.
336    
337    20. Extended pcre_study() to be more clever in cases where a branch of a
338        subpattern has no definite first character. For example, (a*|b*)[cd] would
339        previously give no result from pcre_study(). Now it recognizes that the
340        first character must be a, b, c, or d.
341    
342    21. There was an incorrect error "recursive call could loop indefinitely" if
343        a subpattern (or the entire pattern) that was being tested for matching an
344        empty string contained only one non-empty item after a nested subpattern.
345        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
346        incorrectly, because the \d was being skipped in the check.
347    
348    22. The pcretest program now has a new pattern option /B and a command line
349        option -b, which is equivalent to adding /B to every pattern. This causes
350        it to show the compiled bytecode, without the additional information that
351        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
352        is the same as /B/I).
353    
354    23. A new optimization is now able automatically to treat some sequences such
355        as a*b as a*+b. More specifically, if something simple (such as a character
356        or a simple class like \d) has an unlimited quantifier, and is followed by
357        something that cannot possibly match the quantified thing, the quantifier
358        is automatically "possessified".
359    
360    24. A recursive reference to a subpattern whose number was greater than 39
361        went wrong under certain circumstances in UTF-8 mode. This bug could also
362        have affected the operation of pcre_study().
363    
364    25. Realized that a little bit of performance could be had by replacing
365        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
366    
367    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
368    
369    27. Possessive quantifiers such as a++ were previously implemented by turning
370        them into atomic groups such as ($>a+). Now they have their own opcodes,
371        which improves performance. This includes the automatically created ones
372        from 23 above.
373    
374    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
375        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
376        the first matched character to be a colon. This applied both to named and
377        numbered groups.
378    
379    29. The ucpinternal.h header file was missing its idempotency #ifdef.
380    
381    30. I was sent a "project" file called libpcre.a.dev which I understand makes
382        building PCRE on Windows easier, so I have included it in the distribution.
383    
384    31. There is now a check in pcretest against a ridiculously large number being
385        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
386        loop, the loop is abandoned.
387    
388    32. Forward references to subpatterns in conditions such as (?(2)...) where
389        subpattern 2 is defined later cause pcre_compile() to search forwards in
390        the pattern for the relevant set of parentheses. This search went wrong
391        when there were unescaped parentheses in a character class, parentheses
392        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
393    
394    33. "Subroutine" calls and backreferences were previously restricted to
395        referencing subpatterns earlier in the regex. This restriction has now
396        been removed.
397    
398    34. Added a number of extra features that are going to be in Perl 5.10. On the
399        whole, these are just syntactic alternatives for features that PCRE had
400        previously implemented using the Python syntax or my own invention. The
401        other formats are all retained for compatibility.
402    
403        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
404            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
405            also .NET compatible.
406    
407        (b) A recursion or subroutine call to a named group can now be defined as
408            (?&name) as well as (?P>name).
409    
410        (c) A backreference to a named group can now be defined as \k<name> or
411            \k'name' as well as (?P=name). The new forms, as well as being in Perl
412            5.10, are also .NET compatible.
413    
414        (d) A conditional reference to a named group can now use the syntax
415            (?(<name>) or (?('name') as well as (?(name).
416    
417        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
418            groups (named and numbered) that are never evaluated inline, but can be
419            called as "subroutines" from elsewhere. In effect, the DEFINE condition
420            is always false. There may be only one alternative in such a group.
421    
422        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
423            as the simple (?(R). The condition is true only if the most recent
424            recursion is that of the given number or name. It does not search out
425            through the entire recursion stack.
426    
427        (g) The escape \gN or \g{N} has been added, where N is a positive or
428            negative number, specifying an absolute or relative reference.
429    
430    35. Tidied to get rid of some further signed/unsigned compiler warnings and
431        some "unreachable code" warnings.
432    
433    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
434        things, this adds five new scripts.
435    
436    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
437        There were also incompatibilities regarding the handling of \Q..\E inside
438        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
439        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
440    
441    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
442        matches an empty string, and forcibly breaks the loop. There were bugs in
443        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
444        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
445        separate and independent bugs (that affected different cases) have been
446        fixed.
447    
448    39. Refactored the code to abolish the use of different opcodes for small
449        capturing bracket numbers. This is a tidy that I avoided doing when I
450        removed the limit on the number of capturing brackets for 3.5 back in 2001.
451        The new approach is not only tidier, it makes it possible to reduce the
452        memory needed to fix the previous bug (38).
453    
454    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
455        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
456        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
457        mode.
458    
459    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
460        report.
461    
462    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
463        copy construction and assignment in the C++ wrapper.
464    
465    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
466        couple of bugs that could have given wrong results in the "--newline=crlf"
467        case.
468    
469    44. Added a number of casts and did some reorganization of signed/unsigned int
470        variables following suggestions from Dair Grant. Also renamed the variable
471        "this" as "item" because it is a C++ keyword.
472    
473    45. Arranged for dftables to add
474    
475          #include "pcre_internal.h"
476    
477        to pcre_chartables.c because without it, gcc 4.x may remove the array
478        definition from the final binary if PCRE is built into a static library and
479        dead code stripping is activated.
480    
481    46. For an unanchored pattern, if a match attempt fails at the start of a
482        newline sequence, and the newline setting is CRLF or ANY, and the next two
483        characters are CRLF, advance by two characters instead of one.
484    
485    
486    Version 6.7 04-Jul-06
487    ---------------------
488    
489     1. In order to handle tests when input lines are enormously long, pcretest has
490        been re-factored so that it automatically extends its buffers when
491        necessary. The code is crude, but this _is_ just a test program. The
492        default size has been increased from 32K to 50K.
493    
494     2. The code in pcre_study() was using the value of the re argument before
495        testing it for NULL. (Of course, in any sensible call of the function, it
496        won't be NULL.)
497    
498     3. The memmove() emulation function in pcre_internal.h, which is used on
499        systems that lack both memmove() and bcopy() - that is, hardly ever -
500        was missing a "static" storage class specifier.
501    
502     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
503        containing an extended class (one that cannot be represented by a bitmap
504        because it contains high-valued characters or Unicode property items, e.g.
505        [\pZ]). Almost always one would set UTF-8 mode when processing such a
506        pattern, but PCRE should not loop if you do not (it no longer does).
507        [Detail: two cases were found: (a) a repeated subpattern containing an
508        extended class; (b) a recursive reference to a subpattern that followed a
509        previous extended class. It wasn't skipping over the extended class
510        correctly when UTF-8 mode was not set.]
511    
512     5. A negated single-character class was not being recognized as fixed-length
513        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
514        compile error "lookbehind assertion is not fixed length".
515    
516     6. The RunPerlTest auxiliary script was showing an unexpected difference
517        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
518        write a Perl script that can interpret lines of an input file either as
519        byte characters or as UTF-8, which is what "perltest" was being required to
520        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
521        can't do is switch easily at run time between having the "use utf8;" pragma
522        or not. In the end, I fudged it by using the RunPerlTest script to insert
523        "use utf8;" explicitly for the UTF-8 tests.
524    
525     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
526        the end of the subject string, contrary to the documentation and to what
527        Perl does. This was true of both matching functions. Now it matches only at
528        the start of the subject and immediately after *internal* newlines.
529    
530     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
531        a pointer to an int instead of a pointer to an unsigned long int. This
532        caused problems on 64-bit systems.
533    
534     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
535        instance of the 'standard' template library not being so standard".
536    
537    10. There was no check on the number of named subpatterns nor the maximum
538        length of a subpattern name. The product of these values is used to compute
539        the size of the memory block for a compiled pattern. By supplying a very
540        long subpattern name and a large number of named subpatterns, the size
541        computation could be caused to overflow. This is now prevented by limiting
542        the length of names to 32 characters, and the number of named subpatterns
543        to 10,000.
544    
545    11. Subpatterns that are repeated with specific counts have to be replicated in
546        the compiled pattern. The size of memory for this was computed from the
547        length of the subpattern and the repeat count. The latter is limited to
548        65535, but there was no limit on the former, meaning that integer overflow
549        could in principle occur. The compiled length of a repeated subpattern is
550        now limited to 30,000 bytes in order to prevent this.
551    
552    12. Added the optional facility to have named substrings with the same name.
553    
554    13. Added the ability to use a named substring as a condition, using the
555        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
556        are numbers (not recommended). Forward references are permitted.
557    
558    14. Added forward references in named backreferences (if you see what I mean).
559    
560    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
561        pattern could run off the end of the subject. For example, the pattern
562        "(?s)(.{1,5})"8 did this with the subject "ab".
563    
564    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
565        PCRE_CASELESS was set when matching characters that were quantified with ?
566        or *.
567    
568    17. A character class other than a single negated character that had a minimum
569        but no maximum quantifier - for example [ab]{6,} - was not handled
570        correctly by pce_dfa_exec(). It would match only one character.
571    
572    18. A valid (though odd) pattern that looked like a POSIX character
573        class but used an invalid character after [ (for example [[,abc,]]) caused
574        pcre_compile() to give the error "Failed: internal error: code overflow" or
575        in some cases to crash with a glibc free() error. This could even happen if
576        the pattern terminated after [[ but there just happened to be a sequence of
577        letters, a binary zero, and a closing ] in the memory that followed.
578    
579    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
580        over the years. Originally (before any Unicode support), just the bottom 8
581        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
582        output from "man perlunicode" includes this:
583    
584          The regular expression compiler produces polymorphic opcodes.  That
585          is, the pattern adapts to the data and automatically switches to
586          the Unicode character scheme when presented with Unicode data--or
587          instead uses a traditional byte scheme when presented with byte
588          data.
589    
590        Sadly, a wide octal escape does not cause a switch, and in a string with
591        no other multibyte characters, these octal escapes are treated as before.
592        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
593        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
594        Unicode string.
595    
596        I have not perpetrated such confusion in PCRE. Up till now, it took just
597        the bottom 8 bits, as in old Perl. I have now made octal escapes with
598        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
599        translate to the appropriate multibyte character.
600    
601    29. Applied some refactoring to reduce the number of warnings from Microsoft
602        and Borland compilers. This has included removing the fudge introduced
603        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
604        a warning about an unused variable.
605    
606    21. PCRE has not included VT (character 0x0b) in the set of whitespace
607        characters since release 4.0, because Perl (from release 5.004) does not.
608        [Or at least, is documented not to: some releases seem to be in conflict
609        with the documentation.] However, when a pattern was studied with
610        pcre_study() and all its branches started with \s, PCRE still included VT
611        as a possible starting character. Of course, this did no harm; it just
612        caused an unnecessary match attempt.
613    
614    22. Removed a now-redundant internal flag bit that recorded the fact that case
615        dependency changed within the pattern. This was once needed for "required
616        byte" processing, but is no longer used. This recovers a now-scarce options
617        bit. Also moved the least significant internal flag bit to the most-
618        significant bit of the word, which was not previously used (hangover from
619        the days when it was an int rather than a uint) to free up another bit for
620        the future.
621    
622    23. Added support for CRLF line endings as well as CR and LF. As well as the
623        default being selectable at build time, it can now be changed at runtime
624        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
625        specify that it is scanning data with non-default line endings.
626    
627    24. Changed the definition of CXXLINK to make it agree with the definition of
628        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
629    
630    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
631        recursions. This makes a big different to stack usage for some patterns.
632    
633    26. If a subpattern containing a named recursion or subroutine reference such
634        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
635        the space required for the compiled pattern went wrong and gave too small a
636        value. Depending on the environment, this could lead to "Failed: internal
637        error: code overflow at offset 49" or "glibc detected double free or
638        corruption" errors.
639    
640    27. Applied patches from Google (a) to support the new newline modes and (b) to
641        advance over multibyte UTF-8 characters in GlobalReplace.
642    
643    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
644        difference for some implementation of PCRE in some Windows version.
645    
646    29. Added some extra testing facilities to pcretest:
647    
648        \q<number>   in a data line sets the "match limit" value
649        \Q<number>   in a data line sets the "match recursion limt" value
650        -S <number>  sets the stack size, where <number> is in megabytes
651    
652        The -S option isn't available for Windows.
653    
654    
655    Version 6.6 06-Feb-06
656    ---------------------
657    
658     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
659        in pcreposix.h. I have copied the definition from pcre.h.
660    
661     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
662        because pcre.h is no longer a built file.
663    
664     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
665        not normally included in the compiled code.
666    
667    
668  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
669  ---------------------  ---------------------
670    

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