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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" and "%I64u" instead of "%llu" for
33        long printing in the pcrecpp unittest when running under MinGW.
34    
35     6. ESC_K was left out of the EBCDIC table.
36    
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
50    
51     8. Applied Daniel's patches to solve problems with the import/export magic
52        syntax that is required for Windows, and which was going wrong for the
53        pcreposix and pcrecpp parts of the library. These were overlooked when this
54        problem was solved for the main library.
55    
56     9. There were some crude static tests to avoid integer overflow when computing
57        the size of patterns that contain repeated groups with explicit upper
58        limits. As the maximum quantifier is 65535, the maximum group length was
59        set at 30,000 so that the product of these two numbers did not overflow a
60        32-bit integer. However, it turns out that people want to use groups that
61        are longer than 30,000 bytes (though not repeat them that many times).
62        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63        made it possible to implement the integer overflow checks in a much more
64        dynamic way, which I have now done. The artificial limitation on group
65        length has been removed - we now have only the limit on the total length of
66        the compiled pattern, which depends on the LINK_SIZE setting.
67    
68    
69    Version 7.2 19-Jun-07
70    ---------------------
71    
72     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
73        which is apparently normally available under Windows.
74    
75     2. Re-jig the pcregrep tests with different newline settings in an attempt
76        to make them independent of the local environment's newline setting.
77    
78     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
79    
80     4. Some of the "internals" tests were previously cut out when the link size
81        was not 2, because the output contained actual offsets. The recent new
82        "Z" feature of pcretest means that these can be cut out, making the tests
83        usable with all link sizes.
84    
85     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
86        stack recursion. This gives a massive performance boost under BSD, but just
87        a small improvement under Linux. However, it saves one field in the frame
88        in all cases.
89    
90     6. Added more features from the forthcoming Perl 5.10:
91    
92        (a) (?-n) (where n is a string of digits) is a relative subroutine or
93            recursion call. It refers to the nth most recently opened parentheses.
94    
95        (b) (?+n) is also a relative subroutine call; it refers to the nth next
96            to be opened parentheses.
97    
98        (c) Conditions that refer to capturing parentheses can be specified
99            relatively, for example, (?(-2)... or (?(+3)...
100    
101        (d) \K resets the start of the current match so that everything before
102            is not part of it.
103    
104        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
105    
106        (f) \g{name} is another synonym - part of Perl 5.10's unification of
107            reference syntax.
108    
109        (g) (?| introduces a group in which the numbering of parentheses in each
110            alternative starts with the same number.
111    
112        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
113    
114     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
115        PCRE_INFO_JCHANGED.
116    
117     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
118        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
119        for detecting groups that can match an empty string.
120    
121     9. A pattern with a very large number of alternatives (more than several
122        hundred) was running out of internal workspace during the pre-compile
123        phase, where pcre_compile() figures out how much memory will be needed. A
124        bit of new cunning has reduced the workspace needed for groups with
125        alternatives. The 1000-alternative test pattern now uses 12 bytes of
126        workspace instead of running out of the 4096 that are available.
127    
128    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
129    
130    11. Applied patch from Google to remove an optimization that didn't quite work.
131        The report of the bug said:
132    
133          pcrecpp::RE("a*").FullMatch("aaa") matches, while
134          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
135          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
136    
137    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
138        it matched the wrong number of bytes.
139    
140    
141    Version 7.1 24-Apr-07
142    ---------------------
143    
144     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
145        that is more "standard", making use of automake and other Autotools. There
146        is some re-arrangement of the files and adjustment of comments consequent
147        on this.
148    
149     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
150        for recursive directory scanning broke on some systems because the files
151        are not scanned in any specific order and on different systems the order
152        was different. A call to "sort" has been inserted into RunGrepTest for the
153        approprate test as a short-term fix. In the longer term there may be an
154        alternative.
155    
156     3. I had an email from Eric Raymond about problems translating some of PCRE's
157        man pages to HTML (despite the fact that I distribute HTML pages, some
158        people do their own conversions for various reasons). The problems
159        concerned the use of low-level troff macros .br and .in. I have therefore
160        removed all such uses from the man pages (some were redundant, some could
161        be replaced by .nf/.fi pairs). The 132html script that I use to generate
162        HTML has been updated to handle .nf/.fi and to complain if it encounters
163        .br or .in.
164    
165     4. Updated comments in configure.ac that get placed in config.h.in and also
166        arranged for config.h to be included in the distribution, with the name
167        config.h.generic, for the benefit of those who have to compile without
168        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
169    
170     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
171        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
172        makevp.bat for the current PCRE, using the additional files
173        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
174    
175     6. A Windows user reported a minor discrepancy with test 2, which turned out
176        to be caused by a trailing space on an input line that had got lost in his
177        copy. The trailing space was an accident, so I've just removed it.
178    
179     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
180        that is needed.
181    
182     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
183        as "const" (a) because they are and (b) because it helps the PHP
184        maintainers who have recently made a script to detect big data structures
185        in the php code that should be moved to the .rodata section. I remembered
186        to update Builducptable as well, so it won't revert if ucptable.h is ever
187        re-created.
188    
189     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
190        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
191        order to be able to cut out the UTF-8 tables in the latter when UTF-8
192        support is not required. This saves 1.5-2K of code, which is important in
193        some applications.
194    
195        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
196        so as not to refer to the tables, even though these functions will never be
197        called when UTF-8 support is disabled. Otherwise there are problems with a
198        shared library.
199    
200    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
201    
202        (a) It was defining its arguments as char * instead of void *.
203    
204        (b) It was assuming that all moves were upwards in memory; this was true
205            a long time ago when I wrote it, but is no longer the case.
206    
207        The emulated memove() is provided for those environments that have neither
208        memmove() nor bcopy(). I didn't think anyone used it these days, but that
209        is clearly not the case, as these two bugs were recently reported.
210    
211    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
212        and Detrail to create the HTML documentation, the .txt form of the man
213        pages, and it removes trailing spaces from listed files. It also creates
214        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
215        case, it wraps all the #defines with #ifndefs. This script should be run
216        before "make dist".
217    
218    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
219        with Unicode property support.
220    
221        (a) For a maximizing quantifier, if the two different cases of the
222            character were of different lengths in their UTF-8 codings (there are
223            some cases like this - I found 11), and the matching function had to
224            back up over a mixture of the two cases, it incorrectly assumed they
225            were both the same length.
226    
227        (b) When PCRE was configured to use the heap rather than the stack for
228            recursion during matching, it was not correctly preserving the data for
229            the other case of a UTF-8 character when checking ahead for a match
230            while processing a minimizing repeat. If the check also involved
231            matching a wide character, but failed, corruption could cause an
232            erroneous result when trying to check for a repeat of the original
233            character.
234    
235    13. Some tidying changes to the testing mechanism:
236    
237        (a) The RunTest script now detects the internal link size and whether there
238            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
239            values substituted by "configure". (The RunGrepTest script already did
240            this for UTF-8.) The configure.ac script no longer substitutes the
241            relevant variables.
242    
243        (b) The debugging options /B and /D in pcretest show the compiled bytecode
244            with length and offset values. This means that the output is different
245            for different internal link sizes. Test 2 is skipped for link sizes
246            other than 2 because of this, bypassing the problem. Unfortunately,
247            there was also a test in test 3 (the locale tests) that used /B and
248            failed for link sizes other than 2. Rather than cut the whole test out,
249            I have added a new /Z option to pcretest that replaces the length and
250            offset values with spaces. This is now used to make test 3 independent
251            of link size. (Test 2 will be tidied up later.)
252    
253    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
254        segmentation fault instead of returning the appropriate error message.
255    
256    15. In multiline mode when the newline sequence was set to "any", the pattern
257        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
258        This doesn't seem right; it now treats the CRLF combination as the line
259        ending, and so does not match in that case. It's only a pattern such as ^$
260        that would hit this one: something like ^ABC$ would have failed after \r
261        and then tried again after \r\n.
262    
263    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
264        in an attempt to make files that differ only in their line terminators
265        compare equal. This works on Linux.
266    
267    17. Under certain error circumstances pcregrep might try to free random memory
268        as it exited. This is now fixed, thanks to valgrind.
269    
270    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
271        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
272        was because its rules for how to advance for /g after matching an empty
273        string at the end of a line did not allow for this case. They now check for
274        it specially.
275    
276    20. pcretest is supposed to handle patterns and data of any length, by
277        extending its buffers when necessary. It was getting this wrong when the
278        buffer for a data line had to be extended.
279    
280    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
281        CRLF as a newline sequence.
282    
283    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
284        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
285        I have nevertheless tidied it up.
286    
287    23. Added some casts to kill warnings from HP-UX ia64 compiler.
288    
289    24. Added a man page for pcre-config.
290    
291    
292    Version 7.0 19-Dec-06
293    ---------------------
294    
295     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
296        moving to gcc 4.1.1.
297    
298     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
299        sys/time.h, which is documented as needed for this function. It doesn't
300        seem to matter on Linux, but it showed up on some releases of OS X.
301    
302     3. It seems that there are systems where bytes whose values are greater than
303        127 match isprint() in the "C" locale. The "C" locale should be the
304        default when a C program starts up. In most systems, only ASCII printing
305        characters match isprint(). This difference caused the output from pcretest
306        to vary, making some of the tests fail. I have changed pcretest so that:
307    
308        (a) When it is outputting text in the compiled version of a pattern, bytes
309            other than 32-126 are always shown as hex escapes.
310    
311        (b) When it is outputting text that is a matched part of a subject string,
312            it does the same, unless a different locale has been set for the match
313            (using the /L modifier). In this case, it uses isprint() to decide.
314    
315     4. Fixed a major bug that caused incorrect computation of the amount of memory
316        required for a compiled pattern when options that changed within the
317        pattern affected the logic of the preliminary scan that determines the
318        length. The relevant options are -x, and -i in UTF-8 mode. The result was
319        that the computed length was too small. The symptoms of this bug were
320        either the PCRE error "internal error: code overflow" from pcre_compile(),
321        or a glibc crash with a message such as "pcretest: free(): invalid next
322        size (fast)". Examples of patterns that provoked this bug (shown in
323        pcretest format) are:
324    
325          /(?-x: )/x
326          /(?x)(?-x: \s*#\s*)/
327          /((?i)[\x{c0}])/8
328          /(?i:[\x{c0}])/8
329    
330        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
331        is now done differently.
332    
333     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
334        wrapper classes; (b) implement a new function in the C++ scanner that is
335        more efficient than the old way of doing things because it avoids levels of
336        recursion in the regex matching; (c) add a paragraph to the documentation
337        for the FullMatch() function.
338    
339     6. The escape sequence \n was being treated as whatever was defined as
340        "newline". Not only was this contrary to the documentation, which states
341        that \n is character 10 (hex 0A), but it also went horribly wrong when
342        "newline" was defined as CRLF. This has been fixed.
343    
344     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
345        was being set to -1 for the "end of line" case (supposedly a value that no
346        character can have). Though this value is never used (the check for end of
347        line is "zero bytes in current character"), it caused compiler complaints.
348        I've changed it to 0xffffffff.
349    
350     8. In pcre_version.c, the version string was being built by a sequence of
351        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
352        string (as it is for production releases) called a macro with an empty
353        argument. The C standard says the result of this is undefined. The gcc
354        compiler treats it as an empty string (which was what was wanted) but it is
355        reported that Visual C gives an error. The source has been hacked around to
356        avoid this problem.
357    
358     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
359        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
360        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
361        of them did).
362    
363    10. Originally, pcretest opened its input and output without "b"; then I was
364        told that "b" was needed in some environments, so it was added for release
365        5.0 to both the input and output. (It makes no difference on Unix-like
366        systems.) Later I was told that it is wrong for the input on Windows. I've
367        now abstracted the modes into two macros, to make it easier to fiddle with
368        them, and removed "b" from the input mode under Windows.
369    
370    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
371    
372    12. Added -help and --help to pcretest as an official way of being reminded
373        of the options.
374    
375    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
376        and pcrecpp.cc because they annoy compilers at high warning levels.
377    
378    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
379    
380    15. Fixed an occurrence of == in configure.ac that should have been = (shell
381        scripts are not C programs :-) and which was not noticed because it works
382        on Linux.
383    
384    16. pcretest is supposed to handle any length of pattern and data line (as one
385        line or as a continued sequence of lines) by extending its input buffer if
386        necessary. This feature was broken for very long pattern lines, leading to
387        a string of junk being passed to pcre_compile() if the pattern was longer
388        than about 50K.
389    
390    17. I have done a major re-factoring of the way pcre_compile() computes the
391        amount of memory needed for a compiled pattern. Previously, there was code
392        that made a preliminary scan of the pattern in order to do this. That was
393        OK when PCRE was new, but as the facilities have expanded, it has become
394        harder and harder to keep it in step with the real compile phase, and there
395        have been a number of bugs (see for example, 4 above). I have now found a
396        cunning way of running the real compile function in a "fake" mode that
397        enables it to compute how much memory it would need, while actually only
398        ever using a few hundred bytes of working memory and without too many
399        tests of the mode. This should make future maintenance and development
400        easier. A side effect of this work is that the limit of 200 on the nesting
401        depth of parentheses has been removed (though this was never a serious
402        limitation, I suspect). However, there is a downside: pcre_compile() now
403        runs more slowly than before (30% or more, depending on the pattern). I
404        hope this isn't a big issue. There is no effect on runtime performance.
405    
406    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
407        newline (only possible for the last line of a file) and it was a
408        pattern that set a locale (followed by /Lsomething), pcretest crashed.
409    
410    19. Added additional timing features to pcretest. (1) The -tm option now times
411        matching only, not compiling. (2) Both -t and -tm can be followed, as a
412        separate command line item, by a number that specifies the number of
413        repeats to use when timing. The default is 50000; this gives better
414        precision, but takes uncomfortably long for very large patterns.
415    
416    20. Extended pcre_study() to be more clever in cases where a branch of a
417        subpattern has no definite first character. For example, (a*|b*)[cd] would
418        previously give no result from pcre_study(). Now it recognizes that the
419        first character must be a, b, c, or d.
420    
421    21. There was an incorrect error "recursive call could loop indefinitely" if
422        a subpattern (or the entire pattern) that was being tested for matching an
423        empty string contained only one non-empty item after a nested subpattern.
424        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
425        incorrectly, because the \d was being skipped in the check.
426    
427    22. The pcretest program now has a new pattern option /B and a command line
428        option -b, which is equivalent to adding /B to every pattern. This causes
429        it to show the compiled bytecode, without the additional information that
430        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
431        is the same as /B/I).
432    
433    23. A new optimization is now able automatically to treat some sequences such
434        as a*b as a*+b. More specifically, if something simple (such as a character
435        or a simple class like \d) has an unlimited quantifier, and is followed by
436        something that cannot possibly match the quantified thing, the quantifier
437        is automatically "possessified".
438    
439    24. A recursive reference to a subpattern whose number was greater than 39
440        went wrong under certain circumstances in UTF-8 mode. This bug could also
441        have affected the operation of pcre_study().
442    
443    25. Realized that a little bit of performance could be had by replacing
444        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
445    
446    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
447    
448    27. Possessive quantifiers such as a++ were previously implemented by turning
449        them into atomic groups such as ($>a+). Now they have their own opcodes,
450        which improves performance. This includes the automatically created ones
451        from 23 above.
452    
453    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
454        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
455        the first matched character to be a colon. This applied both to named and
456        numbered groups.
457    
458    29. The ucpinternal.h header file was missing its idempotency #ifdef.
459    
460    30. I was sent a "project" file called libpcre.a.dev which I understand makes
461        building PCRE on Windows easier, so I have included it in the distribution.
462    
463    31. There is now a check in pcretest against a ridiculously large number being
464        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
465        loop, the loop is abandoned.
466    
467    32. Forward references to subpatterns in conditions such as (?(2)...) where
468        subpattern 2 is defined later cause pcre_compile() to search forwards in
469        the pattern for the relevant set of parentheses. This search went wrong
470        when there were unescaped parentheses in a character class, parentheses
471        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
472    
473    33. "Subroutine" calls and backreferences were previously restricted to
474        referencing subpatterns earlier in the regex. This restriction has now
475        been removed.
476    
477    34. Added a number of extra features that are going to be in Perl 5.10. On the
478        whole, these are just syntactic alternatives for features that PCRE had
479        previously implemented using the Python syntax or my own invention. The
480        other formats are all retained for compatibility.
481    
482        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
483            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
484            also .NET compatible.
485    
486        (b) A recursion or subroutine call to a named group can now be defined as
487            (?&name) as well as (?P>name).
488    
489        (c) A backreference to a named group can now be defined as \k<name> or
490            \k'name' as well as (?P=name). The new forms, as well as being in Perl
491            5.10, are also .NET compatible.
492    
493        (d) A conditional reference to a named group can now use the syntax
494            (?(<name>) or (?('name') as well as (?(name).
495    
496        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
497            groups (named and numbered) that are never evaluated inline, but can be
498            called as "subroutines" from elsewhere. In effect, the DEFINE condition
499            is always false. There may be only one alternative in such a group.
500    
501        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
502            as the simple (?(R). The condition is true only if the most recent
503            recursion is that of the given number or name. It does not search out
504            through the entire recursion stack.
505    
506        (g) The escape \gN or \g{N} has been added, where N is a positive or
507            negative number, specifying an absolute or relative reference.
508    
509    35. Tidied to get rid of some further signed/unsigned compiler warnings and
510        some "unreachable code" warnings.
511    
512    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
513        things, this adds five new scripts.
514    
515    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
516        There were also incompatibilities regarding the handling of \Q..\E inside
517        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
518        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
519    
520    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
521        matches an empty string, and forcibly breaks the loop. There were bugs in
522        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
523        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
524        separate and independent bugs (that affected different cases) have been
525        fixed.
526    
527    39. Refactored the code to abolish the use of different opcodes for small
528        capturing bracket numbers. This is a tidy that I avoided doing when I
529        removed the limit on the number of capturing brackets for 3.5 back in 2001.
530        The new approach is not only tidier, it makes it possible to reduce the
531        memory needed to fix the previous bug (38).
532    
533    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
534        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
535        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
536        mode.
537    
538    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
539        report.
540    
541    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
542        copy construction and assignment in the C++ wrapper.
543    
544    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
545        couple of bugs that could have given wrong results in the "--newline=crlf"
546        case.
547    
548    44. Added a number of casts and did some reorganization of signed/unsigned int
549        variables following suggestions from Dair Grant. Also renamed the variable
550        "this" as "item" because it is a C++ keyword.
551    
552    45. Arranged for dftables to add
553    
554          #include "pcre_internal.h"
555    
556        to pcre_chartables.c because without it, gcc 4.x may remove the array
557        definition from the final binary if PCRE is built into a static library and
558        dead code stripping is activated.
559    
560    46. For an unanchored pattern, if a match attempt fails at the start of a
561        newline sequence, and the newline setting is CRLF or ANY, and the next two
562        characters are CRLF, advance by two characters instead of one.
563    
564    
565    Version 6.7 04-Jul-06
566    ---------------------
567    
568     1. In order to handle tests when input lines are enormously long, pcretest has
569        been re-factored so that it automatically extends its buffers when
570        necessary. The code is crude, but this _is_ just a test program. The
571        default size has been increased from 32K to 50K.
572    
573     2. The code in pcre_study() was using the value of the re argument before
574        testing it for NULL. (Of course, in any sensible call of the function, it
575        won't be NULL.)
576    
577     3. The memmove() emulation function in pcre_internal.h, which is used on
578        systems that lack both memmove() and bcopy() - that is, hardly ever -
579        was missing a "static" storage class specifier.
580    
581     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
582        containing an extended class (one that cannot be represented by a bitmap
583        because it contains high-valued characters or Unicode property items, e.g.
584        [\pZ]). Almost always one would set UTF-8 mode when processing such a
585        pattern, but PCRE should not loop if you do not (it no longer does).
586        [Detail: two cases were found: (a) a repeated subpattern containing an
587        extended class; (b) a recursive reference to a subpattern that followed a
588        previous extended class. It wasn't skipping over the extended class
589        correctly when UTF-8 mode was not set.]
590    
591     5. A negated single-character class was not being recognized as fixed-length
592        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
593        compile error "lookbehind assertion is not fixed length".
594    
595     6. The RunPerlTest auxiliary script was showing an unexpected difference
596        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
597        write a Perl script that can interpret lines of an input file either as
598        byte characters or as UTF-8, which is what "perltest" was being required to
599        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
600        can't do is switch easily at run time between having the "use utf8;" pragma
601        or not. In the end, I fudged it by using the RunPerlTest script to insert
602        "use utf8;" explicitly for the UTF-8 tests.
603    
604     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
605        the end of the subject string, contrary to the documentation and to what
606        Perl does. This was true of both matching functions. Now it matches only at
607        the start of the subject and immediately after *internal* newlines.
608    
609     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
610        a pointer to an int instead of a pointer to an unsigned long int. This
611        caused problems on 64-bit systems.
612    
613     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
614        instance of the 'standard' template library not being so standard".
615    
616    10. There was no check on the number of named subpatterns nor the maximum
617        length of a subpattern name. The product of these values is used to compute
618        the size of the memory block for a compiled pattern. By supplying a very
619        long subpattern name and a large number of named subpatterns, the size
620        computation could be caused to overflow. This is now prevented by limiting
621        the length of names to 32 characters, and the number of named subpatterns
622        to 10,000.
623    
624    11. Subpatterns that are repeated with specific counts have to be replicated in
625        the compiled pattern. The size of memory for this was computed from the
626        length of the subpattern and the repeat count. The latter is limited to
627        65535, but there was no limit on the former, meaning that integer overflow
628        could in principle occur. The compiled length of a repeated subpattern is
629        now limited to 30,000 bytes in order to prevent this.
630    
631    12. Added the optional facility to have named substrings with the same name.
632    
633    13. Added the ability to use a named substring as a condition, using the
634        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
635        are numbers (not recommended). Forward references are permitted.
636    
637    14. Added forward references in named backreferences (if you see what I mean).
638    
639    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
640        pattern could run off the end of the subject. For example, the pattern
641        "(?s)(.{1,5})"8 did this with the subject "ab".
642    
643    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
644        PCRE_CASELESS was set when matching characters that were quantified with ?
645        or *.
646    
647    17. A character class other than a single negated character that had a minimum
648        but no maximum quantifier - for example [ab]{6,} - was not handled
649        correctly by pce_dfa_exec(). It would match only one character.
650    
651    18. A valid (though odd) pattern that looked like a POSIX character
652        class but used an invalid character after [ (for example [[,abc,]]) caused
653        pcre_compile() to give the error "Failed: internal error: code overflow" or
654        in some cases to crash with a glibc free() error. This could even happen if
655        the pattern terminated after [[ but there just happened to be a sequence of
656        letters, a binary zero, and a closing ] in the memory that followed.
657    
658    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
659        over the years. Originally (before any Unicode support), just the bottom 8
660        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
661        output from "man perlunicode" includes this:
662    
663          The regular expression compiler produces polymorphic opcodes.  That
664          is, the pattern adapts to the data and automatically switches to
665          the Unicode character scheme when presented with Unicode data--or
666          instead uses a traditional byte scheme when presented with byte
667          data.
668    
669        Sadly, a wide octal escape does not cause a switch, and in a string with
670        no other multibyte characters, these octal escapes are treated as before.
671        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
672        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
673        Unicode string.
674    
675        I have not perpetrated such confusion in PCRE. Up till now, it took just
676        the bottom 8 bits, as in old Perl. I have now made octal escapes with
677        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
678        translate to the appropriate multibyte character.
679    
680    29. Applied some refactoring to reduce the number of warnings from Microsoft
681        and Borland compilers. This has included removing the fudge introduced
682        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
683        a warning about an unused variable.
684    
685    21. PCRE has not included VT (character 0x0b) in the set of whitespace
686        characters since release 4.0, because Perl (from release 5.004) does not.
687        [Or at least, is documented not to: some releases seem to be in conflict
688        with the documentation.] However, when a pattern was studied with
689        pcre_study() and all its branches started with \s, PCRE still included VT
690        as a possible starting character. Of course, this did no harm; it just
691        caused an unnecessary match attempt.
692    
693    22. Removed a now-redundant internal flag bit that recorded the fact that case
694        dependency changed within the pattern. This was once needed for "required
695        byte" processing, but is no longer used. This recovers a now-scarce options
696        bit. Also moved the least significant internal flag bit to the most-
697        significant bit of the word, which was not previously used (hangover from
698        the days when it was an int rather than a uint) to free up another bit for
699        the future.
700    
701    23. Added support for CRLF line endings as well as CR and LF. As well as the
702        default being selectable at build time, it can now be changed at runtime
703        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
704        specify that it is scanning data with non-default line endings.
705    
706    24. Changed the definition of CXXLINK to make it agree with the definition of
707        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
708    
709    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
710        recursions. This makes a big different to stack usage for some patterns.
711    
712    26. If a subpattern containing a named recursion or subroutine reference such
713        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
714        the space required for the compiled pattern went wrong and gave too small a
715        value. Depending on the environment, this could lead to "Failed: internal
716        error: code overflow at offset 49" or "glibc detected double free or
717        corruption" errors.
718    
719    27. Applied patches from Google (a) to support the new newline modes and (b) to
720        advance over multibyte UTF-8 characters in GlobalReplace.
721    
722    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
723        difference for some implementation of PCRE in some Windows version.
724    
725    29. Added some extra testing facilities to pcretest:
726    
727        \q<number>   in a data line sets the "match limit" value
728        \Q<number>   in a data line sets the "match recursion limt" value
729        -S <number>  sets the stack size, where <number> is in megabytes
730    
731        The -S option isn't available for Windows.
732    
733    
734    Version 6.6 06-Feb-06
735    ---------------------
736    
737     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
738        in pcreposix.h. I have copied the definition from pcre.h.
739    
740     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
741        because pcre.h is no longer a built file.
742    
743     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
744        not normally included in the compiled code.
745    
746    
747    Version 6.5 01-Feb-06
748    ---------------------
749    
750     1. When using the partial match feature with pcre_dfa_exec(), it was not
751        anchoring the second and subsequent partial matches at the new starting
752        point. This could lead to incorrect results. For example, with the pattern
753        /1234/, partially matching against "123" and then "a4" gave a match.
754    
755     2. Changes to pcregrep:
756    
757        (a) All non-match returns from pcre_exec() were being treated as failures
758            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
759            error message is output. Some extra information is given for the
760            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
761            probably the only errors that are likely to be caused by users (by
762            specifying a regex that has nested indefinite repeats, for instance).
763            If there are more than 20 of these errors, pcregrep is abandoned.
764    
765        (b) A binary zero was treated as data while matching, but terminated the
766            output line if it was written out. This has been fixed: binary zeroes
767            are now no different to any other data bytes.
768    
769        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
770            used to set a locale for matching. The --locale=xxxx long option has
771            been added (no short equivalent) to specify a locale explicitly on the
772            pcregrep command, overriding the environment variables.
773    
774        (d) When -B was used with -n, some line numbers in the output were one less
775            than they should have been.
776    
777        (e) Added the -o (--only-matching) option.
778    
779        (f) If -A or -C was used with -c (count only), some lines of context were
780            accidentally printed for the final match.
781    
782        (g) Added the -H (--with-filename) option.
783    
784        (h) The combination of options -rh failed to suppress file names for files
785            that were found from directory arguments.
786    
787        (i) Added the -D (--devices) and -d (--directories) options.
788    
789        (j) Added the -F (--fixed-strings) option.
790    
791        (k) Allow "-" to be used as a file name for -f as well as for a data file.
792    
793        (l) Added the --colo(u)r option.
794    
795        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
796            is not present by default.
797    
798     3. A nasty bug was discovered in the handling of recursive patterns, that is,
799        items such as (?R) or (?1), when the recursion could match a number of
800        alternatives. If it matched one of the alternatives, but subsequently,
801        outside the recursion, there was a failure, the code tried to back up into
802        the recursion. However, because of the way PCRE is implemented, this is not
803        possible, and the result was an incorrect result from the match.
804    
805        In order to prevent this happening, the specification of recursion has
806        been changed so that all such subpatterns are automatically treated as
807        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
808    
809     4. I had overlooked the fact that, in some locales, there are characters for
810        which isalpha() is true but neither isupper() nor islower() are true. In
811        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
812        and ordfeminine) are like this. This affected the treatment of \w and \W
813        when they appeared in character classes, but not when they appeared outside
814        a character class. The bit map for "word" characters is now created
815        separately from the results of isalnum() instead of just taking it from the
816        upper, lower, and digit maps. (Plus the underscore character, of course.)
817    
818     5. The above bug also affected the handling of POSIX character classes such as
819        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
820        permanent tables. Instead, the bit maps for such a class were previously
821        created as the appropriate unions of the upper, lower, and digit bitmaps.
822        Now they are created by subtraction from the [[:word:]] class, which has
823        its own bitmap.
824    
825     6. The [[:blank:]] character class matches horizontal, but not vertical space.
826        It is created by subtracting the vertical space characters (\x09, \x0a,
827        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
828        subtraction was done in the overall bitmap for a character class, meaning
829        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
830        be recognized. This bug has been fixed.
831    
832     7. Patches from the folks at Google:
833    
834          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
835          real life, but is still worth protecting against".
836    
837          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
838          regular expressions".
839    
840          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
841          have it.
842    
843          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
844          "configure" and the latter not, in order to fix a problem somebody had
845          with compiling the Arg class on HP-UX.
846    
847          (e) Improve the error-handling of the C++ wrapper a little bit.
848    
849          (f) New tests for checking recursion limiting.
850    
851     8. The pcre_memmove() function, which is used only if the environment does not
852        have a standard memmove() function (and is therefore rarely compiled),
853        contained two bugs: (a) use of int instead of size_t, and (b) it was not
854        returning a result (though PCRE never actually uses the result).
855    
856     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
857        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
858        returned instead of calling malloc() with an overflowing number that would
859        most likely cause subsequent chaos.
860    
861    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
862    
863    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
864        with this option is matched, the nmatch and pmatch options of regexec() are
865        ignored.
866    
867    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
868        provided in case anyone wants to the the POSIX interface with UTF-8
869        strings.
870    
871    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
872        C++ linking (needed for some HP-UX environments).
873    
874    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
875        (unused parameter) and in the pcre_printint() function (omitted "default"
876        switch label when the default is to do nothing).
877    
878    15. Added some code to make it possible, when PCRE is compiled as a C++
879        library, to replace subject pointers for pcre_exec() with a smart pointer
880        class, thus making it possible to process discontinuous strings.
881    
882    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
883        much the same function. They were added by different people who were trying
884        to make PCRE easy to compile on non-Unix systems. It has been suggested
885        that PCRE_EXPORT be abolished now that there is more automatic apparatus
886        for compiling on Windows systems. I have therefore replaced it with
887        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
888        defaults to "extern" for C or "extern C" for C++, which works fine on
889        Unix-like systems. It is now possible to override the value of PCRE_DATA_
890        SCOPE with something explicit in config.h. In addition:
891    
892        (a) pcreposix.h still had just "extern" instead of either of these macros;
893            I have replaced it with PCRE_DATA_SCOPE.
894    
895        (b) Functions such as _pcre_xclass(), which are internal to the library,
896            but external in the C sense, all had PCRE_EXPORT in their definitions.
897            This is apparently wrong for the Windows case, so I have removed it.
898            (It makes no difference on Unix-like systems.)
899    
900    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
901        of recursive calls to match(). This is different to MATCH_LIMIT because
902        that limits the total number of calls to match(), not all of which increase
903        the depth of recursion. Limiting the recursion depth limits the amount of
904        stack (or heap if NO_RECURSE is set) that is used. The default can be set
905        when PCRE is compiled, and changed at run time. A patch from Google adds
906        this functionality to the C++ interface.
907    
908    18. Changes to the handling of Unicode character properties:
909    
910        (a) Updated the table to Unicode 4.1.0.
911    
912        (b) Recognize characters that are not in the table as "Cn" (undefined).
913    
914        (c) I revised the way the table is implemented to a much improved format
915            which includes recognition of ranges. It now supports the ranges that
916            are defined in UnicodeData.txt, and it also amalgamates other
917            characters into ranges. This has reduced the number of entries in the
918            table from around 16,000 to around 3,000, thus reducing its size
919            considerably. I realized I did not need to use a tree structure after
920            all - a binary chop search is just as efficient. Having reduced the
921            number of entries, I extended their size from 6 bytes to 8 bytes to
922            allow for more data.
923    
924        (d) Added support for Unicode script names via properties such as \p{Han}.
925    
926    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
927        matching that character.
928    
929    20. When matching a repeated Unicode property with a minimum greater than zero,
930        (for example \pL{2,}), PCRE could look past the end of the subject if it
931        reached it while seeking the minimum number of characters. This could
932        happen only if some of the characters were more than one byte long, because
933        there is a check for at least the minimum number of bytes.
934    
935    21. Refactored the implementation of \p and \P so as to be more general, to
936        allow for more different types of property in future. This has changed the
937        compiled form incompatibly. Anybody with saved compiled patterns that use
938        \p or \P will have to recompile them.
939    
940    22. Added "Any" and "L&" to the supported property types.
941    
942    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
943        but give a compile time error if the value is greater than 0xff.
944    
945    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
946        accidentally not being installed or uninstalled.
947    
948    25. The pcre.h file was built from pcre.h.in, but the only changes that were
949        made were to insert the current release number. This seemed silly, because
950        it made things harder for people building PCRE on systems that don't run
951        "configure". I have turned pcre.h into a distributed file, no longer built
952        by "configure", with the version identification directly included. There is
953        no longer a pcre.h.in file.
954    
955        However, this change necessitated a change to the pcre-config script as
956        well. It is built from pcre-config.in, and one of the substitutions was the
957        release number. I have updated configure.ac so that ./configure now finds
958        the release number by grepping pcre.h.
959    
960    26. Added the ability to run the tests under valgrind.
961    
962    
963    Version 6.4 05-Sep-05
964    ---------------------
965    
966     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
967        "--" to be printed when multiple files were scanned, even when none of the
968        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
969        consider it to be a bug, and have restored the previous behaviour.
970    
971     2. A couple of code tidies to get rid of compiler warnings.
972    
973     3. The pcretest program used to cheat by referring to symbols in the library
974        whose names begin with _pcre_. These are internal symbols that are not
975        really supposed to be visible externally, and in some environments it is
976        possible to suppress them. The cheating is now confined to including
977        certain files from the library's source, which is a bit cleaner.
978    
979     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
980        file's purpose clearer.
981    
982     5. Reorganized pcre_ucp_findchar().
983    
984    
985    Version 6.3 15-Aug-05
986    ---------------------
987    
988     1. The file libpcre.pc.in did not have general read permission in the tarball.
989    
990     2. There were some problems when building without C++ support:
991    
992        (a) If C++ support was not built, "make install" and "make test" still
993            tried to test it.
994    
995        (b) There were problems when the value of CXX was explicitly set. Some
996            changes have been made to try to fix these, and ...
997    
998        (c) --disable-cpp can now be used to explicitly disable C++ support.
999    
1000        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1001            backslash in a target when C++ was disabled. This confuses some
1002            versions of "make", apparently. Using an intermediate variable solves
1003            this. (Same for CPP_LOBJ.)
1004    
1005     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1006        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1007        necessary on certain architectures.
1008    
1009     4. Added a setting of -export-symbols-regex to the link command to remove
1010        those symbols that are exported in the C sense, but actually are local
1011        within the library, and not documented. Their names all begin with
1012        "_pcre_". This is not a perfect job, because (a) we have to except some
1013        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1014        available (and never for static libraries). I have made a note to try to
1015        find a way round (a) in the future.
1016    
1017    
1018  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
1019  ---------------------  ---------------------
1020    

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