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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.3 05-Jul-07
5    ---------------------
6    
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
12    
13          #include "pcre.h"
14    
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
18    
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
26    
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
28    
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
31    
32     5. Arrange to use "%I64d" instead of "%lld" for long printing in the pcrecpp
33        unittest when running under MinGW.
34    
35    
36    
37    Version 7.2 19-Jun-07
38    ---------------------
39    
40     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
41        which is apparently normally available under Windows.
42    
43     2. Re-jig the pcregrep tests with different newline settings in an attempt
44        to make them independent of the local environment's newline setting.
45    
46     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
47    
48     4. Some of the "internals" tests were previously cut out when the link size
49        was not 2, because the output contained actual offsets. The recent new
50        "Z" feature of pcretest means that these can be cut out, making the tests
51        usable with all link sizes.
52    
53     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
54        stack recursion. This gives a massive performance boost under BSD, but just
55        a small improvement under Linux. However, it saves one field in the frame
56        in all cases.
57    
58     6. Added more features from the forthcoming Perl 5.10:
59    
60        (a) (?-n) (where n is a string of digits) is a relative subroutine or
61            recursion call. It refers to the nth most recently opened parentheses.
62    
63        (b) (?+n) is also a relative subroutine call; it refers to the nth next
64            to be opened parentheses.
65    
66        (c) Conditions that refer to capturing parentheses can be specified
67            relatively, for example, (?(-2)... or (?(+3)...
68    
69        (d) \K resets the start of the current match so that everything before
70            is not part of it.
71    
72        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
73    
74        (f) \g{name} is another synonym - part of Perl 5.10's unification of
75            reference syntax.
76    
77        (g) (?| introduces a group in which the numbering of parentheses in each
78            alternative starts with the same number.
79    
80        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
81    
82     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
83        PCRE_INFO_JCHANGED.
84    
85     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
86        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
87        for detecting groups that can match an empty string.
88    
89     9. A pattern with a very large number of alternatives (more than several
90        hundred) was running out of internal workspace during the pre-compile
91        phase, where pcre_compile() figures out how much memory will be needed. A
92        bit of new cunning has reduced the workspace needed for groups with
93        alternatives. The 1000-alternative test pattern now uses 12 bytes of
94        workspace instead of running out of the 4096 that are available.
95    
96    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
97    
98    11. Applied patch from Google to remove an optimization that didn't quite work.
99        The report of the bug said:
100    
101          pcrecpp::RE("a*").FullMatch("aaa") matches, while
102          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
103          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
104    
105    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
106        it matched the wrong number of bytes.
107    
108    
109    Version 7.1 24-Apr-07
110    ---------------------
111    
112     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
113        that is more "standard", making use of automake and other Autotools. There
114        is some re-arrangement of the files and adjustment of comments consequent
115        on this.
116    
117     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
118        for recursive directory scanning broke on some systems because the files
119        are not scanned in any specific order and on different systems the order
120        was different. A call to "sort" has been inserted into RunGrepTest for the
121        approprate test as a short-term fix. In the longer term there may be an
122        alternative.
123    
124     3. I had an email from Eric Raymond about problems translating some of PCRE's
125        man pages to HTML (despite the fact that I distribute HTML pages, some
126        people do their own conversions for various reasons). The problems
127        concerned the use of low-level troff macros .br and .in. I have therefore
128        removed all such uses from the man pages (some were redundant, some could
129        be replaced by .nf/.fi pairs). The 132html script that I use to generate
130        HTML has been updated to handle .nf/.fi and to complain if it encounters
131        .br or .in.
132    
133     4. Updated comments in configure.ac that get placed in config.h.in and also
134        arranged for config.h to be included in the distribution, with the name
135        config.h.generic, for the benefit of those who have to compile without
136        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
137    
138     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
139        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
140        makevp.bat for the current PCRE, using the additional files
141        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
142    
143     6. A Windows user reported a minor discrepancy with test 2, which turned out
144        to be caused by a trailing space on an input line that had got lost in his
145        copy. The trailing space was an accident, so I've just removed it.
146    
147     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
148        that is needed.
149    
150     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
151        as "const" (a) because they are and (b) because it helps the PHP
152        maintainers who have recently made a script to detect big data structures
153        in the php code that should be moved to the .rodata section. I remembered
154        to update Builducptable as well, so it won't revert if ucptable.h is ever
155        re-created.
156    
157     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
158        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
159        order to be able to cut out the UTF-8 tables in the latter when UTF-8
160        support is not required. This saves 1.5-2K of code, which is important in
161        some applications.
162    
163        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
164        so as not to refer to the tables, even though these functions will never be
165        called when UTF-8 support is disabled. Otherwise there are problems with a
166        shared library.
167    
168    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
169    
170        (a) It was defining its arguments as char * instead of void *.
171    
172        (b) It was assuming that all moves were upwards in memory; this was true
173            a long time ago when I wrote it, but is no longer the case.
174    
175        The emulated memove() is provided for those environments that have neither
176        memmove() nor bcopy(). I didn't think anyone used it these days, but that
177        is clearly not the case, as these two bugs were recently reported.
178    
179    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
180        and Detrail to create the HTML documentation, the .txt form of the man
181        pages, and it removes trailing spaces from listed files. It also creates
182        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
183        case, it wraps all the #defines with #ifndefs. This script should be run
184        before "make dist".
185    
186    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
187        with Unicode property support.
188    
189        (a) For a maximizing quantifier, if the two different cases of the
190            character were of different lengths in their UTF-8 codings (there are
191            some cases like this - I found 11), and the matching function had to
192            back up over a mixture of the two cases, it incorrectly assumed they
193            were both the same length.
194    
195        (b) When PCRE was configured to use the heap rather than the stack for
196            recursion during matching, it was not correctly preserving the data for
197            the other case of a UTF-8 character when checking ahead for a match
198            while processing a minimizing repeat. If the check also involved
199            matching a wide character, but failed, corruption could cause an
200            erroneous result when trying to check for a repeat of the original
201            character.
202    
203    13. Some tidying changes to the testing mechanism:
204    
205        (a) The RunTest script now detects the internal link size and whether there
206            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
207            values substituted by "configure". (The RunGrepTest script already did
208            this for UTF-8.) The configure.ac script no longer substitutes the
209            relevant variables.
210    
211        (b) The debugging options /B and /D in pcretest show the compiled bytecode
212            with length and offset values. This means that the output is different
213            for different internal link sizes. Test 2 is skipped for link sizes
214            other than 2 because of this, bypassing the problem. Unfortunately,
215            there was also a test in test 3 (the locale tests) that used /B and
216            failed for link sizes other than 2. Rather than cut the whole test out,
217            I have added a new /Z option to pcretest that replaces the length and
218            offset values with spaces. This is now used to make test 3 independent
219            of link size. (Test 2 will be tidied up later.)
220    
221    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
222        segmentation fault instead of returning the appropriate error message.
223    
224    15. In multiline mode when the newline sequence was set to "any", the pattern
225        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
226        This doesn't seem right; it now treats the CRLF combination as the line
227        ending, and so does not match in that case. It's only a pattern such as ^$
228        that would hit this one: something like ^ABC$ would have failed after \r
229        and then tried again after \r\n.
230    
231    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
232        in an attempt to make files that differ only in their line terminators
233        compare equal. This works on Linux.
234    
235    17. Under certain error circumstances pcregrep might try to free random memory
236        as it exited. This is now fixed, thanks to valgrind.
237    
238    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
239        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
240        was because its rules for how to advance for /g after matching an empty
241        string at the end of a line did not allow for this case. They now check for
242        it specially.
243    
244    20. pcretest is supposed to handle patterns and data of any length, by
245        extending its buffers when necessary. It was getting this wrong when the
246        buffer for a data line had to be extended.
247    
248    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
249        CRLF as a newline sequence.
250    
251    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
252        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
253        I have nevertheless tidied it up.
254    
255    23. Added some casts to kill warnings from HP-UX ia64 compiler.
256    
257    24. Added a man page for pcre-config.
258    
259    
260    Version 7.0 19-Dec-06
261    ---------------------
262    
263     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
264        moving to gcc 4.1.1.
265    
266     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
267        sys/time.h, which is documented as needed for this function. It doesn't
268        seem to matter on Linux, but it showed up on some releases of OS X.
269    
270     3. It seems that there are systems where bytes whose values are greater than
271        127 match isprint() in the "C" locale. The "C" locale should be the
272        default when a C program starts up. In most systems, only ASCII printing
273        characters match isprint(). This difference caused the output from pcretest
274        to vary, making some of the tests fail. I have changed pcretest so that:
275    
276        (a) When it is outputting text in the compiled version of a pattern, bytes
277            other than 32-126 are always shown as hex escapes.
278    
279        (b) When it is outputting text that is a matched part of a subject string,
280            it does the same, unless a different locale has been set for the match
281            (using the /L modifier). In this case, it uses isprint() to decide.
282    
283     4. Fixed a major bug that caused incorrect computation of the amount of memory
284        required for a compiled pattern when options that changed within the
285        pattern affected the logic of the preliminary scan that determines the
286        length. The relevant options are -x, and -i in UTF-8 mode. The result was
287        that the computed length was too small. The symptoms of this bug were
288        either the PCRE error "internal error: code overflow" from pcre_compile(),
289        or a glibc crash with a message such as "pcretest: free(): invalid next
290        size (fast)". Examples of patterns that provoked this bug (shown in
291        pcretest format) are:
292    
293          /(?-x: )/x
294          /(?x)(?-x: \s*#\s*)/
295          /((?i)[\x{c0}])/8
296          /(?i:[\x{c0}])/8
297    
298        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
299        is now done differently.
300    
301     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
302        wrapper classes; (b) implement a new function in the C++ scanner that is
303        more efficient than the old way of doing things because it avoids levels of
304        recursion in the regex matching; (c) add a paragraph to the documentation
305        for the FullMatch() function.
306    
307     6. The escape sequence \n was being treated as whatever was defined as
308        "newline". Not only was this contrary to the documentation, which states
309        that \n is character 10 (hex 0A), but it also went horribly wrong when
310        "newline" was defined as CRLF. This has been fixed.
311    
312     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
313        was being set to -1 for the "end of line" case (supposedly a value that no
314        character can have). Though this value is never used (the check for end of
315        line is "zero bytes in current character"), it caused compiler complaints.
316        I've changed it to 0xffffffff.
317    
318     8. In pcre_version.c, the version string was being built by a sequence of
319        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
320        string (as it is for production releases) called a macro with an empty
321        argument. The C standard says the result of this is undefined. The gcc
322        compiler treats it as an empty string (which was what was wanted) but it is
323        reported that Visual C gives an error. The source has been hacked around to
324        avoid this problem.
325    
326     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
327        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
328        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
329        of them did).
330    
331    10. Originally, pcretest opened its input and output without "b"; then I was
332        told that "b" was needed in some environments, so it was added for release
333        5.0 to both the input and output. (It makes no difference on Unix-like
334        systems.) Later I was told that it is wrong for the input on Windows. I've
335        now abstracted the modes into two macros, to make it easier to fiddle with
336        them, and removed "b" from the input mode under Windows.
337    
338    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
339    
340    12. Added -help and --help to pcretest as an official way of being reminded
341        of the options.
342    
343    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
344        and pcrecpp.cc because they annoy compilers at high warning levels.
345    
346    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
347    
348    15. Fixed an occurrence of == in configure.ac that should have been = (shell
349        scripts are not C programs :-) and which was not noticed because it works
350        on Linux.
351    
352    16. pcretest is supposed to handle any length of pattern and data line (as one
353        line or as a continued sequence of lines) by extending its input buffer if
354        necessary. This feature was broken for very long pattern lines, leading to
355        a string of junk being passed to pcre_compile() if the pattern was longer
356        than about 50K.
357    
358    17. I have done a major re-factoring of the way pcre_compile() computes the
359        amount of memory needed for a compiled pattern. Previously, there was code
360        that made a preliminary scan of the pattern in order to do this. That was
361        OK when PCRE was new, but as the facilities have expanded, it has become
362        harder and harder to keep it in step with the real compile phase, and there
363        have been a number of bugs (see for example, 4 above). I have now found a
364        cunning way of running the real compile function in a "fake" mode that
365        enables it to compute how much memory it would need, while actually only
366        ever using a few hundred bytes of working memory and without too many
367        tests of the mode. This should make future maintenance and development
368        easier. A side effect of this work is that the limit of 200 on the nesting
369        depth of parentheses has been removed (though this was never a serious
370        limitation, I suspect). However, there is a downside: pcre_compile() now
371        runs more slowly than before (30% or more, depending on the pattern). I
372        hope this isn't a big issue. There is no effect on runtime performance.
373    
374    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
375        newline (only possible for the last line of a file) and it was a
376        pattern that set a locale (followed by /Lsomething), pcretest crashed.
377    
378    19. Added additional timing features to pcretest. (1) The -tm option now times
379        matching only, not compiling. (2) Both -t and -tm can be followed, as a
380        separate command line item, by a number that specifies the number of
381        repeats to use when timing. The default is 50000; this gives better
382        precision, but takes uncomfortably long for very large patterns.
383    
384    20. Extended pcre_study() to be more clever in cases where a branch of a
385        subpattern has no definite first character. For example, (a*|b*)[cd] would
386        previously give no result from pcre_study(). Now it recognizes that the
387        first character must be a, b, c, or d.
388    
389    21. There was an incorrect error "recursive call could loop indefinitely" if
390        a subpattern (or the entire pattern) that was being tested for matching an
391        empty string contained only one non-empty item after a nested subpattern.
392        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
393        incorrectly, because the \d was being skipped in the check.
394    
395    22. The pcretest program now has a new pattern option /B and a command line
396        option -b, which is equivalent to adding /B to every pattern. This causes
397        it to show the compiled bytecode, without the additional information that
398        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
399        is the same as /B/I).
400    
401    23. A new optimization is now able automatically to treat some sequences such
402        as a*b as a*+b. More specifically, if something simple (such as a character
403        or a simple class like \d) has an unlimited quantifier, and is followed by
404        something that cannot possibly match the quantified thing, the quantifier
405        is automatically "possessified".
406    
407    24. A recursive reference to a subpattern whose number was greater than 39
408        went wrong under certain circumstances in UTF-8 mode. This bug could also
409        have affected the operation of pcre_study().
410    
411    25. Realized that a little bit of performance could be had by replacing
412        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
413    
414    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
415    
416    27. Possessive quantifiers such as a++ were previously implemented by turning
417        them into atomic groups such as ($>a+). Now they have their own opcodes,
418        which improves performance. This includes the automatically created ones
419        from 23 above.
420    
421    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
422        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
423        the first matched character to be a colon. This applied both to named and
424        numbered groups.
425    
426    29. The ucpinternal.h header file was missing its idempotency #ifdef.
427    
428    30. I was sent a "project" file called libpcre.a.dev which I understand makes
429        building PCRE on Windows easier, so I have included it in the distribution.
430    
431    31. There is now a check in pcretest against a ridiculously large number being
432        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
433        loop, the loop is abandoned.
434    
435    32. Forward references to subpatterns in conditions such as (?(2)...) where
436        subpattern 2 is defined later cause pcre_compile() to search forwards in
437        the pattern for the relevant set of parentheses. This search went wrong
438        when there were unescaped parentheses in a character class, parentheses
439        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
440    
441    33. "Subroutine" calls and backreferences were previously restricted to
442        referencing subpatterns earlier in the regex. This restriction has now
443        been removed.
444    
445    34. Added a number of extra features that are going to be in Perl 5.10. On the
446        whole, these are just syntactic alternatives for features that PCRE had
447        previously implemented using the Python syntax or my own invention. The
448        other formats are all retained for compatibility.
449    
450        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
451            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
452            also .NET compatible.
453    
454        (b) A recursion or subroutine call to a named group can now be defined as
455            (?&name) as well as (?P>name).
456    
457        (c) A backreference to a named group can now be defined as \k<name> or
458            \k'name' as well as (?P=name). The new forms, as well as being in Perl
459            5.10, are also .NET compatible.
460    
461        (d) A conditional reference to a named group can now use the syntax
462            (?(<name>) or (?('name') as well as (?(name).
463    
464        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
465            groups (named and numbered) that are never evaluated inline, but can be
466            called as "subroutines" from elsewhere. In effect, the DEFINE condition
467            is always false. There may be only one alternative in such a group.
468    
469        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
470            as the simple (?(R). The condition is true only if the most recent
471            recursion is that of the given number or name. It does not search out
472            through the entire recursion stack.
473    
474        (g) The escape \gN or \g{N} has been added, where N is a positive or
475            negative number, specifying an absolute or relative reference.
476    
477    35. Tidied to get rid of some further signed/unsigned compiler warnings and
478        some "unreachable code" warnings.
479    
480    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
481        things, this adds five new scripts.
482    
483    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
484        There were also incompatibilities regarding the handling of \Q..\E inside
485        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
486        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
487    
488    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
489        matches an empty string, and forcibly breaks the loop. There were bugs in
490        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
491        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
492        separate and independent bugs (that affected different cases) have been
493        fixed.
494    
495    39. Refactored the code to abolish the use of different opcodes for small
496        capturing bracket numbers. This is a tidy that I avoided doing when I
497        removed the limit on the number of capturing brackets for 3.5 back in 2001.
498        The new approach is not only tidier, it makes it possible to reduce the
499        memory needed to fix the previous bug (38).
500    
501    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
502        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
503        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
504        mode.
505    
506    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
507        report.
508    
509    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
510        copy construction and assignment in the C++ wrapper.
511    
512    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
513        couple of bugs that could have given wrong results in the "--newline=crlf"
514        case.
515    
516    44. Added a number of casts and did some reorganization of signed/unsigned int
517        variables following suggestions from Dair Grant. Also renamed the variable
518        "this" as "item" because it is a C++ keyword.
519    
520    45. Arranged for dftables to add
521    
522          #include "pcre_internal.h"
523    
524        to pcre_chartables.c because without it, gcc 4.x may remove the array
525        definition from the final binary if PCRE is built into a static library and
526        dead code stripping is activated.
527    
528    46. For an unanchored pattern, if a match attempt fails at the start of a
529        newline sequence, and the newline setting is CRLF or ANY, and the next two
530        characters are CRLF, advance by two characters instead of one.
531    
532    
533    Version 6.7 04-Jul-06
534    ---------------------
535    
536     1. In order to handle tests when input lines are enormously long, pcretest has
537        been re-factored so that it automatically extends its buffers when
538        necessary. The code is crude, but this _is_ just a test program. The
539        default size has been increased from 32K to 50K.
540    
541     2. The code in pcre_study() was using the value of the re argument before
542        testing it for NULL. (Of course, in any sensible call of the function, it
543        won't be NULL.)
544    
545     3. The memmove() emulation function in pcre_internal.h, which is used on
546        systems that lack both memmove() and bcopy() - that is, hardly ever -
547        was missing a "static" storage class specifier.
548    
549     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
550        containing an extended class (one that cannot be represented by a bitmap
551        because it contains high-valued characters or Unicode property items, e.g.
552        [\pZ]). Almost always one would set UTF-8 mode when processing such a
553        pattern, but PCRE should not loop if you do not (it no longer does).
554        [Detail: two cases were found: (a) a repeated subpattern containing an
555        extended class; (b) a recursive reference to a subpattern that followed a
556        previous extended class. It wasn't skipping over the extended class
557        correctly when UTF-8 mode was not set.]
558    
559     5. A negated single-character class was not being recognized as fixed-length
560        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
561        compile error "lookbehind assertion is not fixed length".
562    
563     6. The RunPerlTest auxiliary script was showing an unexpected difference
564        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
565        write a Perl script that can interpret lines of an input file either as
566        byte characters or as UTF-8, which is what "perltest" was being required to
567        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
568        can't do is switch easily at run time between having the "use utf8;" pragma
569        or not. In the end, I fudged it by using the RunPerlTest script to insert
570        "use utf8;" explicitly for the UTF-8 tests.
571    
572     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
573        the end of the subject string, contrary to the documentation and to what
574        Perl does. This was true of both matching functions. Now it matches only at
575        the start of the subject and immediately after *internal* newlines.
576    
577     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
578        a pointer to an int instead of a pointer to an unsigned long int. This
579        caused problems on 64-bit systems.
580    
581     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
582        instance of the 'standard' template library not being so standard".
583    
584    10. There was no check on the number of named subpatterns nor the maximum
585        length of a subpattern name. The product of these values is used to compute
586        the size of the memory block for a compiled pattern. By supplying a very
587        long subpattern name and a large number of named subpatterns, the size
588        computation could be caused to overflow. This is now prevented by limiting
589        the length of names to 32 characters, and the number of named subpatterns
590        to 10,000.
591    
592    11. Subpatterns that are repeated with specific counts have to be replicated in
593        the compiled pattern. The size of memory for this was computed from the
594        length of the subpattern and the repeat count. The latter is limited to
595        65535, but there was no limit on the former, meaning that integer overflow
596        could in principle occur. The compiled length of a repeated subpattern is
597        now limited to 30,000 bytes in order to prevent this.
598    
599    12. Added the optional facility to have named substrings with the same name.
600    
601    13. Added the ability to use a named substring as a condition, using the
602        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
603        are numbers (not recommended). Forward references are permitted.
604    
605    14. Added forward references in named backreferences (if you see what I mean).
606    
607    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
608        pattern could run off the end of the subject. For example, the pattern
609        "(?s)(.{1,5})"8 did this with the subject "ab".
610    
611    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
612        PCRE_CASELESS was set when matching characters that were quantified with ?
613        or *.
614    
615    17. A character class other than a single negated character that had a minimum
616        but no maximum quantifier - for example [ab]{6,} - was not handled
617        correctly by pce_dfa_exec(). It would match only one character.
618    
619    18. A valid (though odd) pattern that looked like a POSIX character
620        class but used an invalid character after [ (for example [[,abc,]]) caused
621        pcre_compile() to give the error "Failed: internal error: code overflow" or
622        in some cases to crash with a glibc free() error. This could even happen if
623        the pattern terminated after [[ but there just happened to be a sequence of
624        letters, a binary zero, and a closing ] in the memory that followed.
625    
626    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
627        over the years. Originally (before any Unicode support), just the bottom 8
628        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
629        output from "man perlunicode" includes this:
630    
631          The regular expression compiler produces polymorphic opcodes.  That
632          is, the pattern adapts to the data and automatically switches to
633          the Unicode character scheme when presented with Unicode data--or
634          instead uses a traditional byte scheme when presented with byte
635          data.
636    
637        Sadly, a wide octal escape does not cause a switch, and in a string with
638        no other multibyte characters, these octal escapes are treated as before.
639        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
640        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
641        Unicode string.
642    
643        I have not perpetrated such confusion in PCRE. Up till now, it took just
644        the bottom 8 bits, as in old Perl. I have now made octal escapes with
645        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
646        translate to the appropriate multibyte character.
647    
648    29. Applied some refactoring to reduce the number of warnings from Microsoft
649        and Borland compilers. This has included removing the fudge introduced
650        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
651        a warning about an unused variable.
652    
653    21. PCRE has not included VT (character 0x0b) in the set of whitespace
654        characters since release 4.0, because Perl (from release 5.004) does not.
655        [Or at least, is documented not to: some releases seem to be in conflict
656        with the documentation.] However, when a pattern was studied with
657        pcre_study() and all its branches started with \s, PCRE still included VT
658        as a possible starting character. Of course, this did no harm; it just
659        caused an unnecessary match attempt.
660    
661    22. Removed a now-redundant internal flag bit that recorded the fact that case
662        dependency changed within the pattern. This was once needed for "required
663        byte" processing, but is no longer used. This recovers a now-scarce options
664        bit. Also moved the least significant internal flag bit to the most-
665        significant bit of the word, which was not previously used (hangover from
666        the days when it was an int rather than a uint) to free up another bit for
667        the future.
668    
669    23. Added support for CRLF line endings as well as CR and LF. As well as the
670        default being selectable at build time, it can now be changed at runtime
671        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
672        specify that it is scanning data with non-default line endings.
673    
674    24. Changed the definition of CXXLINK to make it agree with the definition of
675        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
676    
677    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
678        recursions. This makes a big different to stack usage for some patterns.
679    
680    26. If a subpattern containing a named recursion or subroutine reference such
681        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
682        the space required for the compiled pattern went wrong and gave too small a
683        value. Depending on the environment, this could lead to "Failed: internal
684        error: code overflow at offset 49" or "glibc detected double free or
685        corruption" errors.
686    
687    27. Applied patches from Google (a) to support the new newline modes and (b) to
688        advance over multibyte UTF-8 characters in GlobalReplace.
689    
690    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
691        difference for some implementation of PCRE in some Windows version.
692    
693    29. Added some extra testing facilities to pcretest:
694    
695        \q<number>   in a data line sets the "match limit" value
696        \Q<number>   in a data line sets the "match recursion limt" value
697        -S <number>  sets the stack size, where <number> is in megabytes
698    
699        The -S option isn't available for Windows.
700    
701    
702    Version 6.6 06-Feb-06
703    ---------------------
704    
705     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
706        in pcreposix.h. I have copied the definition from pcre.h.
707    
708     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
709        because pcre.h is no longer a built file.
710    
711     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
712        not normally included in the compiled code.
713    
714    
715    Version 6.5 01-Feb-06
716    ---------------------
717    
718     1. When using the partial match feature with pcre_dfa_exec(), it was not
719        anchoring the second and subsequent partial matches at the new starting
720        point. This could lead to incorrect results. For example, with the pattern
721        /1234/, partially matching against "123" and then "a4" gave a match.
722    
723     2. Changes to pcregrep:
724    
725        (a) All non-match returns from pcre_exec() were being treated as failures
726            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
727            error message is output. Some extra information is given for the
728            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
729            probably the only errors that are likely to be caused by users (by
730            specifying a regex that has nested indefinite repeats, for instance).
731            If there are more than 20 of these errors, pcregrep is abandoned.
732    
733        (b) A binary zero was treated as data while matching, but terminated the
734            output line if it was written out. This has been fixed: binary zeroes
735            are now no different to any other data bytes.
736    
737        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
738            used to set a locale for matching. The --locale=xxxx long option has
739            been added (no short equivalent) to specify a locale explicitly on the
740            pcregrep command, overriding the environment variables.
741    
742        (d) When -B was used with -n, some line numbers in the output were one less
743            than they should have been.
744    
745        (e) Added the -o (--only-matching) option.
746    
747        (f) If -A or -C was used with -c (count only), some lines of context were
748            accidentally printed for the final match.
749    
750        (g) Added the -H (--with-filename) option.
751    
752        (h) The combination of options -rh failed to suppress file names for files
753            that were found from directory arguments.
754    
755        (i) Added the -D (--devices) and -d (--directories) options.
756    
757        (j) Added the -F (--fixed-strings) option.
758    
759        (k) Allow "-" to be used as a file name for -f as well as for a data file.
760    
761        (l) Added the --colo(u)r option.
762    
763        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
764            is not present by default.
765    
766     3. A nasty bug was discovered in the handling of recursive patterns, that is,
767        items such as (?R) or (?1), when the recursion could match a number of
768        alternatives. If it matched one of the alternatives, but subsequently,
769        outside the recursion, there was a failure, the code tried to back up into
770        the recursion. However, because of the way PCRE is implemented, this is not
771        possible, and the result was an incorrect result from the match.
772    
773        In order to prevent this happening, the specification of recursion has
774        been changed so that all such subpatterns are automatically treated as
775        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
776    
777     4. I had overlooked the fact that, in some locales, there are characters for
778        which isalpha() is true but neither isupper() nor islower() are true. In
779        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
780        and ordfeminine) are like this. This affected the treatment of \w and \W
781        when they appeared in character classes, but not when they appeared outside
782        a character class. The bit map for "word" characters is now created
783        separately from the results of isalnum() instead of just taking it from the
784        upper, lower, and digit maps. (Plus the underscore character, of course.)
785    
786     5. The above bug also affected the handling of POSIX character classes such as
787        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
788        permanent tables. Instead, the bit maps for such a class were previously
789        created as the appropriate unions of the upper, lower, and digit bitmaps.
790        Now they are created by subtraction from the [[:word:]] class, which has
791        its own bitmap.
792    
793     6. The [[:blank:]] character class matches horizontal, but not vertical space.
794        It is created by subtracting the vertical space characters (\x09, \x0a,
795        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
796        subtraction was done in the overall bitmap for a character class, meaning
797        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
798        be recognized. This bug has been fixed.
799    
800     7. Patches from the folks at Google:
801    
802          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
803          real life, but is still worth protecting against".
804    
805          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
806          regular expressions".
807    
808          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
809          have it.
810    
811          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
812          "configure" and the latter not, in order to fix a problem somebody had
813          with compiling the Arg class on HP-UX.
814    
815          (e) Improve the error-handling of the C++ wrapper a little bit.
816    
817          (f) New tests for checking recursion limiting.
818    
819     8. The pcre_memmove() function, which is used only if the environment does not
820        have a standard memmove() function (and is therefore rarely compiled),
821        contained two bugs: (a) use of int instead of size_t, and (b) it was not
822        returning a result (though PCRE never actually uses the result).
823    
824     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
825        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
826        returned instead of calling malloc() with an overflowing number that would
827        most likely cause subsequent chaos.
828    
829    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
830    
831    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
832        with this option is matched, the nmatch and pmatch options of regexec() are
833        ignored.
834    
835    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
836        provided in case anyone wants to the the POSIX interface with UTF-8
837        strings.
838    
839    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
840        C++ linking (needed for some HP-UX environments).
841    
842    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
843        (unused parameter) and in the pcre_printint() function (omitted "default"
844        switch label when the default is to do nothing).
845    
846    15. Added some code to make it possible, when PCRE is compiled as a C++
847        library, to replace subject pointers for pcre_exec() with a smart pointer
848        class, thus making it possible to process discontinuous strings.
849    
850    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
851        much the same function. They were added by different people who were trying
852        to make PCRE easy to compile on non-Unix systems. It has been suggested
853        that PCRE_EXPORT be abolished now that there is more automatic apparatus
854        for compiling on Windows systems. I have therefore replaced it with
855        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
856        defaults to "extern" for C or "extern C" for C++, which works fine on
857        Unix-like systems. It is now possible to override the value of PCRE_DATA_
858        SCOPE with something explicit in config.h. In addition:
859    
860        (a) pcreposix.h still had just "extern" instead of either of these macros;
861            I have replaced it with PCRE_DATA_SCOPE.
862    
863        (b) Functions such as _pcre_xclass(), which are internal to the library,
864            but external in the C sense, all had PCRE_EXPORT in their definitions.
865            This is apparently wrong for the Windows case, so I have removed it.
866            (It makes no difference on Unix-like systems.)
867    
868    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
869        of recursive calls to match(). This is different to MATCH_LIMIT because
870        that limits the total number of calls to match(), not all of which increase
871        the depth of recursion. Limiting the recursion depth limits the amount of
872        stack (or heap if NO_RECURSE is set) that is used. The default can be set
873        when PCRE is compiled, and changed at run time. A patch from Google adds
874        this functionality to the C++ interface.
875    
876    18. Changes to the handling of Unicode character properties:
877    
878        (a) Updated the table to Unicode 4.1.0.
879    
880        (b) Recognize characters that are not in the table as "Cn" (undefined).
881    
882        (c) I revised the way the table is implemented to a much improved format
883            which includes recognition of ranges. It now supports the ranges that
884            are defined in UnicodeData.txt, and it also amalgamates other
885            characters into ranges. This has reduced the number of entries in the
886            table from around 16,000 to around 3,000, thus reducing its size
887            considerably. I realized I did not need to use a tree structure after
888            all - a binary chop search is just as efficient. Having reduced the
889            number of entries, I extended their size from 6 bytes to 8 bytes to
890            allow for more data.
891    
892        (d) Added support for Unicode script names via properties such as \p{Han}.
893    
894    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
895        matching that character.
896    
897    20. When matching a repeated Unicode property with a minimum greater than zero,
898        (for example \pL{2,}), PCRE could look past the end of the subject if it
899        reached it while seeking the minimum number of characters. This could
900        happen only if some of the characters were more than one byte long, because
901        there is a check for at least the minimum number of bytes.
902    
903    21. Refactored the implementation of \p and \P so as to be more general, to
904        allow for more different types of property in future. This has changed the
905        compiled form incompatibly. Anybody with saved compiled patterns that use
906        \p or \P will have to recompile them.
907    
908    22. Added "Any" and "L&" to the supported property types.
909    
910    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
911        but give a compile time error if the value is greater than 0xff.
912    
913    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
914        accidentally not being installed or uninstalled.
915    
916    25. The pcre.h file was built from pcre.h.in, but the only changes that were
917        made were to insert the current release number. This seemed silly, because
918        it made things harder for people building PCRE on systems that don't run
919        "configure". I have turned pcre.h into a distributed file, no longer built
920        by "configure", with the version identification directly included. There is
921        no longer a pcre.h.in file.
922    
923        However, this change necessitated a change to the pcre-config script as
924        well. It is built from pcre-config.in, and one of the substitutions was the
925        release number. I have updated configure.ac so that ./configure now finds
926        the release number by grepping pcre.h.
927    
928    26. Added the ability to run the tests under valgrind.
929    
930    
931  Version 6.4 05-Sep-05  Version 6.4 05-Sep-05
932  ---------------------  ---------------------
933    

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