ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 27 by nigel, Sat Feb 24 21:38:49 2007 UTC revision 217 by ph10, Wed Aug 15 15:21:04 2007 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.3 09-Aug-07
5    ---------------------
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:
13          #include "pcre.h"
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.
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.
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
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.
35     6. ESC_K was left out of the EBCDIC table.
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.
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.
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.
68    10. Fixed a bug in the documentation for get/copy named substring when
69        duplicate names are permitted. If none of the named substrings are set, the
70        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71        empty string.
73    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75        because the ] is interpreted as the first data character and the
76        terminating ] is not found. PCRE has been made compatible with Perl in this
77        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78        cause memory overwriting.
80    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81        string has been matched (to stop an infinite loop). It was not recognizing
82        a conditional subpattern that could match an empty string if that
83        subpattern was within another subpattern. For example, it looped when
84        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
85        condition was not nested. This bug has been fixed.
87    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88        past the start of the subject in the presence of bytes with the top bit
89        set, for example "\x8aBCD".
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
94    14. Optimized (?!) to (*FAIL).
96    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97        This restricts code points to be within the range 0 to 0x10FFFF, excluding
98        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100        does: it's just the validity check that is more restrictive.
102    16. Inserted checks for integer overflows during escape sequence (backslash)
103        processing, and also fixed erroneous offset values for syntax errors during
104        backslash processing.
106    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
112    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113        something other than just ASCII characters) inside a group that had an
114        unlimited repeat caused a loop at compile time (while checking to see
115        whether the group could match an empty string).
117    20. Debugging a pattern containing \p or \P could cause a crash. For example,
118        [\P{Any}] did so. (Error in the code for printing property names.)
121    Version 7.2 19-Jun-07
122    ---------------------
124     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
125        which is apparently normally available under Windows.
127     2. Re-jig the pcregrep tests with different newline settings in an attempt
128        to make them independent of the local environment's newline setting.
130     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
132     4. Some of the "internals" tests were previously cut out when the link size
133        was not 2, because the output contained actual offsets. The recent new
134        "Z" feature of pcretest means that these can be cut out, making the tests
135        usable with all link sizes.
137     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
138        stack recursion. This gives a massive performance boost under BSD, but just
139        a small improvement under Linux. However, it saves one field in the frame
140        in all cases.
142     6. Added more features from the forthcoming Perl 5.10:
144        (a) (?-n) (where n is a string of digits) is a relative subroutine or
145            recursion call. It refers to the nth most recently opened parentheses.
147        (b) (?+n) is also a relative subroutine call; it refers to the nth next
148            to be opened parentheses.
150        (c) Conditions that refer to capturing parentheses can be specified
151            relatively, for example, (?(-2)... or (?(+3)...
153        (d) \K resets the start of the current match so that everything before
154            is not part of it.
156        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
158        (f) \g{name} is another synonym - part of Perl 5.10's unification of
159            reference syntax.
161        (g) (?| introduces a group in which the numbering of parentheses in each
162            alternative starts with the same number.
164        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
166     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
169     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
170        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
171        for detecting groups that can match an empty string.
173     9. A pattern with a very large number of alternatives (more than several
174        hundred) was running out of internal workspace during the pre-compile
175        phase, where pcre_compile() figures out how much memory will be needed. A
176        bit of new cunning has reduced the workspace needed for groups with
177        alternatives. The 1000-alternative test pattern now uses 12 bytes of
178        workspace instead of running out of the 4096 that are available.
180    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
182    11. Applied patch from Google to remove an optimization that didn't quite work.
183        The report of the bug said:
185          pcrecpp::RE("a*").FullMatch("aaa") matches, while
186          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
187          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
189    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
190        it matched the wrong number of bytes.
193    Version 7.1 24-Apr-07
194    ---------------------
196     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
197        that is more "standard", making use of automake and other Autotools. There
198        is some re-arrangement of the files and adjustment of comments consequent
199        on this.
201     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
202        for recursive directory scanning broke on some systems because the files
203        are not scanned in any specific order and on different systems the order
204        was different. A call to "sort" has been inserted into RunGrepTest for the
205        approprate test as a short-term fix. In the longer term there may be an
206        alternative.
208     3. I had an email from Eric Raymond about problems translating some of PCRE's
209        man pages to HTML (despite the fact that I distribute HTML pages, some
210        people do their own conversions for various reasons). The problems
211        concerned the use of low-level troff macros .br and .in. I have therefore
212        removed all such uses from the man pages (some were redundant, some could
213        be replaced by .nf/.fi pairs). The 132html script that I use to generate
214        HTML has been updated to handle .nf/.fi and to complain if it encounters
215        .br or .in.
217     4. Updated comments in configure.ac that get placed in config.h.in and also
218        arranged for config.h to be included in the distribution, with the name
219        config.h.generic, for the benefit of those who have to compile without
220        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
222     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
223        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
224        makevp.bat for the current PCRE, using the additional files
225        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
227     6. A Windows user reported a minor discrepancy with test 2, which turned out
228        to be caused by a trailing space on an input line that had got lost in his
229        copy. The trailing space was an accident, so I've just removed it.
231     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
232        that is needed.
234     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
235        as "const" (a) because they are and (b) because it helps the PHP
236        maintainers who have recently made a script to detect big data structures
237        in the php code that should be moved to the .rodata section. I remembered
238        to update Builducptable as well, so it won't revert if ucptable.h is ever
239        re-created.
241     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
242        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
243        order to be able to cut out the UTF-8 tables in the latter when UTF-8
244        support is not required. This saves 1.5-2K of code, which is important in
245        some applications.
247        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
248        so as not to refer to the tables, even though these functions will never be
249        called when UTF-8 support is disabled. Otherwise there are problems with a
250        shared library.
252    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
254        (a) It was defining its arguments as char * instead of void *.
256        (b) It was assuming that all moves were upwards in memory; this was true
257            a long time ago when I wrote it, but is no longer the case.
259        The emulated memove() is provided for those environments that have neither
260        memmove() nor bcopy(). I didn't think anyone used it these days, but that
261        is clearly not the case, as these two bugs were recently reported.
263    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
264        and Detrail to create the HTML documentation, the .txt form of the man
265        pages, and it removes trailing spaces from listed files. It also creates
266        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
267        case, it wraps all the #defines with #ifndefs. This script should be run
268        before "make dist".
270    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
271        with Unicode property support.
273        (a) For a maximizing quantifier, if the two different cases of the
274            character were of different lengths in their UTF-8 codings (there are
275            some cases like this - I found 11), and the matching function had to
276            back up over a mixture of the two cases, it incorrectly assumed they
277            were both the same length.
279        (b) When PCRE was configured to use the heap rather than the stack for
280            recursion during matching, it was not correctly preserving the data for
281            the other case of a UTF-8 character when checking ahead for a match
282            while processing a minimizing repeat. If the check also involved
283            matching a wide character, but failed, corruption could cause an
284            erroneous result when trying to check for a repeat of the original
285            character.
287    13. Some tidying changes to the testing mechanism:
289        (a) The RunTest script now detects the internal link size and whether there
290            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
291            values substituted by "configure". (The RunGrepTest script already did
292            this for UTF-8.) The configure.ac script no longer substitutes the
293            relevant variables.
295        (b) The debugging options /B and /D in pcretest show the compiled bytecode
296            with length and offset values. This means that the output is different
297            for different internal link sizes. Test 2 is skipped for link sizes
298            other than 2 because of this, bypassing the problem. Unfortunately,
299            there was also a test in test 3 (the locale tests) that used /B and
300            failed for link sizes other than 2. Rather than cut the whole test out,
301            I have added a new /Z option to pcretest that replaces the length and
302            offset values with spaces. This is now used to make test 3 independent
303            of link size. (Test 2 will be tidied up later.)
305    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
306        segmentation fault instead of returning the appropriate error message.
308    15. In multiline mode when the newline sequence was set to "any", the pattern
309        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
310        This doesn't seem right; it now treats the CRLF combination as the line
311        ending, and so does not match in that case. It's only a pattern such as ^$
312        that would hit this one: something like ^ABC$ would have failed after \r
313        and then tried again after \r\n.
315    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
316        in an attempt to make files that differ only in their line terminators
317        compare equal. This works on Linux.
319    17. Under certain error circumstances pcregrep might try to free random memory
320        as it exited. This is now fixed, thanks to valgrind.
322    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
323        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
324        was because its rules for how to advance for /g after matching an empty
325        string at the end of a line did not allow for this case. They now check for
326        it specially.
328    20. pcretest is supposed to handle patterns and data of any length, by
329        extending its buffers when necessary. It was getting this wrong when the
330        buffer for a data line had to be extended.
332    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
333        CRLF as a newline sequence.
335    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
336        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
337        I have nevertheless tidied it up.
339    23. Added some casts to kill warnings from HP-UX ia64 compiler.
341    24. Added a man page for pcre-config.
344    Version 7.0 19-Dec-06
345    ---------------------
347     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
348        moving to gcc 4.1.1.
350     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
351        sys/time.h, which is documented as needed for this function. It doesn't
352        seem to matter on Linux, but it showed up on some releases of OS X.
354     3. It seems that there are systems where bytes whose values are greater than
355        127 match isprint() in the "C" locale. The "C" locale should be the
356        default when a C program starts up. In most systems, only ASCII printing
357        characters match isprint(). This difference caused the output from pcretest
358        to vary, making some of the tests fail. I have changed pcretest so that:
360        (a) When it is outputting text in the compiled version of a pattern, bytes
361            other than 32-126 are always shown as hex escapes.
363        (b) When it is outputting text that is a matched part of a subject string,
364            it does the same, unless a different locale has been set for the match
365            (using the /L modifier). In this case, it uses isprint() to decide.
367     4. Fixed a major bug that caused incorrect computation of the amount of memory
368        required for a compiled pattern when options that changed within the
369        pattern affected the logic of the preliminary scan that determines the
370        length. The relevant options are -x, and -i in UTF-8 mode. The result was
371        that the computed length was too small. The symptoms of this bug were
372        either the PCRE error "internal error: code overflow" from pcre_compile(),
373        or a glibc crash with a message such as "pcretest: free(): invalid next
374        size (fast)". Examples of patterns that provoked this bug (shown in
375        pcretest format) are:
377          /(?-x: )/x
378          /(?x)(?-x: \s*#\s*)/
379          /((?i)[\x{c0}])/8
380          /(?i:[\x{c0}])/8
382        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
383        is now done differently.
385     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
386        wrapper classes; (b) implement a new function in the C++ scanner that is
387        more efficient than the old way of doing things because it avoids levels of
388        recursion in the regex matching; (c) add a paragraph to the documentation
389        for the FullMatch() function.
391     6. The escape sequence \n was being treated as whatever was defined as
392        "newline". Not only was this contrary to the documentation, which states
393        that \n is character 10 (hex 0A), but it also went horribly wrong when
394        "newline" was defined as CRLF. This has been fixed.
396     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
397        was being set to -1 for the "end of line" case (supposedly a value that no
398        character can have). Though this value is never used (the check for end of
399        line is "zero bytes in current character"), it caused compiler complaints.
400        I've changed it to 0xffffffff.
402     8. In pcre_version.c, the version string was being built by a sequence of
403        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
404        string (as it is for production releases) called a macro with an empty
405        argument. The C standard says the result of this is undefined. The gcc
406        compiler treats it as an empty string (which was what was wanted) but it is
407        reported that Visual C gives an error. The source has been hacked around to
408        avoid this problem.
410     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
411        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
412        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
413        of them did).
415    10. Originally, pcretest opened its input and output without "b"; then I was
416        told that "b" was needed in some environments, so it was added for release
417        5.0 to both the input and output. (It makes no difference on Unix-like
418        systems.) Later I was told that it is wrong for the input on Windows. I've
419        now abstracted the modes into two macros, to make it easier to fiddle with
420        them, and removed "b" from the input mode under Windows.
422    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
424    12. Added -help and --help to pcretest as an official way of being reminded
425        of the options.
427    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
428        and pcrecpp.cc because they annoy compilers at high warning levels.
430    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
432    15. Fixed an occurrence of == in configure.ac that should have been = (shell
433        scripts are not C programs :-) and which was not noticed because it works
434        on Linux.
436    16. pcretest is supposed to handle any length of pattern and data line (as one
437        line or as a continued sequence of lines) by extending its input buffer if
438        necessary. This feature was broken for very long pattern lines, leading to
439        a string of junk being passed to pcre_compile() if the pattern was longer
440        than about 50K.
442    17. I have done a major re-factoring of the way pcre_compile() computes the
443        amount of memory needed for a compiled pattern. Previously, there was code
444        that made a preliminary scan of the pattern in order to do this. That was
445        OK when PCRE was new, but as the facilities have expanded, it has become
446        harder and harder to keep it in step with the real compile phase, and there
447        have been a number of bugs (see for example, 4 above). I have now found a
448        cunning way of running the real compile function in a "fake" mode that
449        enables it to compute how much memory it would need, while actually only
450        ever using a few hundred bytes of working memory and without too many
451        tests of the mode. This should make future maintenance and development
452        easier. A side effect of this work is that the limit of 200 on the nesting
453        depth of parentheses has been removed (though this was never a serious
454        limitation, I suspect). However, there is a downside: pcre_compile() now
455        runs more slowly than before (30% or more, depending on the pattern). I
456        hope this isn't a big issue. There is no effect on runtime performance.
458    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
459        newline (only possible for the last line of a file) and it was a
460        pattern that set a locale (followed by /Lsomething), pcretest crashed.
462    19. Added additional timing features to pcretest. (1) The -tm option now times
463        matching only, not compiling. (2) Both -t and -tm can be followed, as a
464        separate command line item, by a number that specifies the number of
465        repeats to use when timing. The default is 50000; this gives better
466        precision, but takes uncomfortably long for very large patterns.
468    20. Extended pcre_study() to be more clever in cases where a branch of a
469        subpattern has no definite first character. For example, (a*|b*)[cd] would
470        previously give no result from pcre_study(). Now it recognizes that the
471        first character must be a, b, c, or d.
473    21. There was an incorrect error "recursive call could loop indefinitely" if
474        a subpattern (or the entire pattern) that was being tested for matching an
475        empty string contained only one non-empty item after a nested subpattern.
476        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
477        incorrectly, because the \d was being skipped in the check.
479    22. The pcretest program now has a new pattern option /B and a command line
480        option -b, which is equivalent to adding /B to every pattern. This causes
481        it to show the compiled bytecode, without the additional information that
482        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
483        is the same as /B/I).
485    23. A new optimization is now able automatically to treat some sequences such
486        as a*b as a*+b. More specifically, if something simple (such as a character
487        or a simple class like \d) has an unlimited quantifier, and is followed by
488        something that cannot possibly match the quantified thing, the quantifier
489        is automatically "possessified".
491    24. A recursive reference to a subpattern whose number was greater than 39
492        went wrong under certain circumstances in UTF-8 mode. This bug could also
493        have affected the operation of pcre_study().
495    25. Realized that a little bit of performance could be had by replacing
496        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
498    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
500    27. Possessive quantifiers such as a++ were previously implemented by turning
501        them into atomic groups such as ($>a+). Now they have their own opcodes,
502        which improves performance. This includes the automatically created ones
503        from 23 above.
505    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
506        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
507        the first matched character to be a colon. This applied both to named and
508        numbered groups.
510    29. The ucpinternal.h header file was missing its idempotency #ifdef.
512    30. I was sent a "project" file called libpcre.a.dev which I understand makes
513        building PCRE on Windows easier, so I have included it in the distribution.
515    31. There is now a check in pcretest against a ridiculously large number being
516        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
517        loop, the loop is abandoned.
519    32. Forward references to subpatterns in conditions such as (?(2)...) where
520        subpattern 2 is defined later cause pcre_compile() to search forwards in
521        the pattern for the relevant set of parentheses. This search went wrong
522        when there were unescaped parentheses in a character class, parentheses
523        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
525    33. "Subroutine" calls and backreferences were previously restricted to
526        referencing subpatterns earlier in the regex. This restriction has now
527        been removed.
529    34. Added a number of extra features that are going to be in Perl 5.10. On the
530        whole, these are just syntactic alternatives for features that PCRE had
531        previously implemented using the Python syntax or my own invention. The
532        other formats are all retained for compatibility.
534        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
535            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
536            also .NET compatible.
538        (b) A recursion or subroutine call to a named group can now be defined as
539            (?&name) as well as (?P>name).
541        (c) A backreference to a named group can now be defined as \k<name> or
542            \k'name' as well as (?P=name). The new forms, as well as being in Perl
543            5.10, are also .NET compatible.
545        (d) A conditional reference to a named group can now use the syntax
546            (?(<name>) or (?('name') as well as (?(name).
548        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
549            groups (named and numbered) that are never evaluated inline, but can be
550            called as "subroutines" from elsewhere. In effect, the DEFINE condition
551            is always false. There may be only one alternative in such a group.
553        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
554            as the simple (?(R). The condition is true only if the most recent
555            recursion is that of the given number or name. It does not search out
556            through the entire recursion stack.
558        (g) The escape \gN or \g{N} has been added, where N is a positive or
559            negative number, specifying an absolute or relative reference.
561    35. Tidied to get rid of some further signed/unsigned compiler warnings and
562        some "unreachable code" warnings.
564    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
565        things, this adds five new scripts.
567    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
568        There were also incompatibilities regarding the handling of \Q..\E inside
569        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
570        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
572    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
573        matches an empty string, and forcibly breaks the loop. There were bugs in
574        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
575        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
576        separate and independent bugs (that affected different cases) have been
577        fixed.
579    39. Refactored the code to abolish the use of different opcodes for small
580        capturing bracket numbers. This is a tidy that I avoided doing when I
581        removed the limit on the number of capturing brackets for 3.5 back in 2001.
582        The new approach is not only tidier, it makes it possible to reduce the
583        memory needed to fix the previous bug (38).
585    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
586        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
587        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
588        mode.
590    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
591        report.
593    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
594        copy construction and assignment in the C++ wrapper.
596    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
597        couple of bugs that could have given wrong results in the "--newline=crlf"
598        case.
600    44. Added a number of casts and did some reorganization of signed/unsigned int
601        variables following suggestions from Dair Grant. Also renamed the variable
602        "this" as "item" because it is a C++ keyword.
604    45. Arranged for dftables to add
606          #include "pcre_internal.h"
608        to pcre_chartables.c because without it, gcc 4.x may remove the array
609        definition from the final binary if PCRE is built into a static library and
610        dead code stripping is activated.
612    46. For an unanchored pattern, if a match attempt fails at the start of a
613        newline sequence, and the newline setting is CRLF or ANY, and the next two
614        characters are CRLF, advance by two characters instead of one.
617    Version 6.7 04-Jul-06
618    ---------------------
620     1. In order to handle tests when input lines are enormously long, pcretest has
621        been re-factored so that it automatically extends its buffers when
622        necessary. The code is crude, but this _is_ just a test program. The
623        default size has been increased from 32K to 50K.
625     2. The code in pcre_study() was using the value of the re argument before
626        testing it for NULL. (Of course, in any sensible call of the function, it
627        won't be NULL.)
629     3. The memmove() emulation function in pcre_internal.h, which is used on
630        systems that lack both memmove() and bcopy() - that is, hardly ever -
631        was missing a "static" storage class specifier.
633     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
634        containing an extended class (one that cannot be represented by a bitmap
635        because it contains high-valued characters or Unicode property items, e.g.
636        [\pZ]). Almost always one would set UTF-8 mode when processing such a
637        pattern, but PCRE should not loop if you do not (it no longer does).
638        [Detail: two cases were found: (a) a repeated subpattern containing an
639        extended class; (b) a recursive reference to a subpattern that followed a
640        previous extended class. It wasn't skipping over the extended class
641        correctly when UTF-8 mode was not set.]
643     5. A negated single-character class was not being recognized as fixed-length
644        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
645        compile error "lookbehind assertion is not fixed length".
647     6. The RunPerlTest auxiliary script was showing an unexpected difference
648        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
649        write a Perl script that can interpret lines of an input file either as
650        byte characters or as UTF-8, which is what "perltest" was being required to
651        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
652        can't do is switch easily at run time between having the "use utf8;" pragma
653        or not. In the end, I fudged it by using the RunPerlTest script to insert
654        "use utf8;" explicitly for the UTF-8 tests.
656     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
657        the end of the subject string, contrary to the documentation and to what
658        Perl does. This was true of both matching functions. Now it matches only at
659        the start of the subject and immediately after *internal* newlines.
661     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
662        a pointer to an int instead of a pointer to an unsigned long int. This
663        caused problems on 64-bit systems.
665     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
666        instance of the 'standard' template library not being so standard".
668    10. There was no check on the number of named subpatterns nor the maximum
669        length of a subpattern name. The product of these values is used to compute
670        the size of the memory block for a compiled pattern. By supplying a very
671        long subpattern name and a large number of named subpatterns, the size
672        computation could be caused to overflow. This is now prevented by limiting
673        the length of names to 32 characters, and the number of named subpatterns
674        to 10,000.
676    11. Subpatterns that are repeated with specific counts have to be replicated in
677        the compiled pattern. The size of memory for this was computed from the
678        length of the subpattern and the repeat count. The latter is limited to
679        65535, but there was no limit on the former, meaning that integer overflow
680        could in principle occur. The compiled length of a repeated subpattern is
681        now limited to 30,000 bytes in order to prevent this.
683    12. Added the optional facility to have named substrings with the same name.
685    13. Added the ability to use a named substring as a condition, using the
686        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
687        are numbers (not recommended). Forward references are permitted.
689    14. Added forward references in named backreferences (if you see what I mean).
691    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
692        pattern could run off the end of the subject. For example, the pattern
693        "(?s)(.{1,5})"8 did this with the subject "ab".
695    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
696        PCRE_CASELESS was set when matching characters that were quantified with ?
697        or *.
699    17. A character class other than a single negated character that had a minimum
700        but no maximum quantifier - for example [ab]{6,} - was not handled
701        correctly by pce_dfa_exec(). It would match only one character.
703    18. A valid (though odd) pattern that looked like a POSIX character
704        class but used an invalid character after [ (for example [[,abc,]]) caused
705        pcre_compile() to give the error "Failed: internal error: code overflow" or
706        in some cases to crash with a glibc free() error. This could even happen if
707        the pattern terminated after [[ but there just happened to be a sequence of
708        letters, a binary zero, and a closing ] in the memory that followed.
710    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
711        over the years. Originally (before any Unicode support), just the bottom 8
712        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
713        output from "man perlunicode" includes this:
715          The regular expression compiler produces polymorphic opcodes.  That
716          is, the pattern adapts to the data and automatically switches to
717          the Unicode character scheme when presented with Unicode data--or
718          instead uses a traditional byte scheme when presented with byte
719          data.
721        Sadly, a wide octal escape does not cause a switch, and in a string with
722        no other multibyte characters, these octal escapes are treated as before.
723        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
724        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
725        Unicode string.
727        I have not perpetrated such confusion in PCRE. Up till now, it took just
728        the bottom 8 bits, as in old Perl. I have now made octal escapes with
729        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
730        translate to the appropriate multibyte character.
732    29. Applied some refactoring to reduce the number of warnings from Microsoft
733        and Borland compilers. This has included removing the fudge introduced
734        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
735        a warning about an unused variable.
737    21. PCRE has not included VT (character 0x0b) in the set of whitespace
738        characters since release 4.0, because Perl (from release 5.004) does not.
739        [Or at least, is documented not to: some releases seem to be in conflict
740        with the documentation.] However, when a pattern was studied with
741        pcre_study() and all its branches started with \s, PCRE still included VT
742        as a possible starting character. Of course, this did no harm; it just
743        caused an unnecessary match attempt.
745    22. Removed a now-redundant internal flag bit that recorded the fact that case
746        dependency changed within the pattern. This was once needed for "required
747        byte" processing, but is no longer used. This recovers a now-scarce options
748        bit. Also moved the least significant internal flag bit to the most-
749        significant bit of the word, which was not previously used (hangover from
750        the days when it was an int rather than a uint) to free up another bit for
751        the future.
753    23. Added support for CRLF line endings as well as CR and LF. As well as the
754        default being selectable at build time, it can now be changed at runtime
755        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
756        specify that it is scanning data with non-default line endings.
758    24. Changed the definition of CXXLINK to make it agree with the definition of
759        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
761    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
762        recursions. This makes a big different to stack usage for some patterns.
764    26. If a subpattern containing a named recursion or subroutine reference such
765        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
766        the space required for the compiled pattern went wrong and gave too small a
767        value. Depending on the environment, this could lead to "Failed: internal
768        error: code overflow at offset 49" or "glibc detected double free or
769        corruption" errors.
771    27. Applied patches from Google (a) to support the new newline modes and (b) to
772        advance over multibyte UTF-8 characters in GlobalReplace.
774    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
775        difference for some implementation of PCRE in some Windows version.
777    29. Added some extra testing facilities to pcretest:
779        \q<number>   in a data line sets the "match limit" value
780        \Q<number>   in a data line sets the "match recursion limt" value
781        -S <number>  sets the stack size, where <number> is in megabytes
783        The -S option isn't available for Windows.
786    Version 6.6 06-Feb-06
787    ---------------------
789     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
790        in pcreposix.h. I have copied the definition from pcre.h.
792     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
793        because pcre.h is no longer a built file.
795     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
796        not normally included in the compiled code.
799    Version 6.5 01-Feb-06
800    ---------------------
802     1. When using the partial match feature with pcre_dfa_exec(), it was not
803        anchoring the second and subsequent partial matches at the new starting
804        point. This could lead to incorrect results. For example, with the pattern
805        /1234/, partially matching against "123" and then "a4" gave a match.
807     2. Changes to pcregrep:
809        (a) All non-match returns from pcre_exec() were being treated as failures
810            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
811            error message is output. Some extra information is given for the
812            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
813            probably the only errors that are likely to be caused by users (by
814            specifying a regex that has nested indefinite repeats, for instance).
815            If there are more than 20 of these errors, pcregrep is abandoned.
817        (b) A binary zero was treated as data while matching, but terminated the
818            output line if it was written out. This has been fixed: binary zeroes
819            are now no different to any other data bytes.
821        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
822            used to set a locale for matching. The --locale=xxxx long option has
823            been added (no short equivalent) to specify a locale explicitly on the
824            pcregrep command, overriding the environment variables.
826        (d) When -B was used with -n, some line numbers in the output were one less
827            than they should have been.
829        (e) Added the -o (--only-matching) option.
831        (f) If -A or -C was used with -c (count only), some lines of context were
832            accidentally printed for the final match.
834        (g) Added the -H (--with-filename) option.
836        (h) The combination of options -rh failed to suppress file names for files
837            that were found from directory arguments.
839        (i) Added the -D (--devices) and -d (--directories) options.
841        (j) Added the -F (--fixed-strings) option.
843        (k) Allow "-" to be used as a file name for -f as well as for a data file.
845        (l) Added the --colo(u)r option.
847        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
848            is not present by default.
850     3. A nasty bug was discovered in the handling of recursive patterns, that is,
851        items such as (?R) or (?1), when the recursion could match a number of
852        alternatives. If it matched one of the alternatives, but subsequently,
853        outside the recursion, there was a failure, the code tried to back up into
854        the recursion. However, because of the way PCRE is implemented, this is not
855        possible, and the result was an incorrect result from the match.
857        In order to prevent this happening, the specification of recursion has
858        been changed so that all such subpatterns are automatically treated as
859        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
861     4. I had overlooked the fact that, in some locales, there are characters for
862        which isalpha() is true but neither isupper() nor islower() are true. In
863        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
864        and ordfeminine) are like this. This affected the treatment of \w and \W
865        when they appeared in character classes, but not when they appeared outside
866        a character class. The bit map for "word" characters is now created
867        separately from the results of isalnum() instead of just taking it from the
868        upper, lower, and digit maps. (Plus the underscore character, of course.)
870     5. The above bug also affected the handling of POSIX character classes such as
871        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
872        permanent tables. Instead, the bit maps for such a class were previously
873        created as the appropriate unions of the upper, lower, and digit bitmaps.
874        Now they are created by subtraction from the [[:word:]] class, which has
875        its own bitmap.
877     6. The [[:blank:]] character class matches horizontal, but not vertical space.
878        It is created by subtracting the vertical space characters (\x09, \x0a,
879        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
880        subtraction was done in the overall bitmap for a character class, meaning
881        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
882        be recognized. This bug has been fixed.
884     7. Patches from the folks at Google:
886          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
887          real life, but is still worth protecting against".
889          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
890          regular expressions".
892          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
893          have it.
895          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
896          "configure" and the latter not, in order to fix a problem somebody had
897          with compiling the Arg class on HP-UX.
899          (e) Improve the error-handling of the C++ wrapper a little bit.
901          (f) New tests for checking recursion limiting.
903     8. The pcre_memmove() function, which is used only if the environment does not
904        have a standard memmove() function (and is therefore rarely compiled),
905        contained two bugs: (a) use of int instead of size_t, and (b) it was not
906        returning a result (though PCRE never actually uses the result).
908     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
909        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
910        returned instead of calling malloc() with an overflowing number that would
911        most likely cause subsequent chaos.
913    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
915    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
916        with this option is matched, the nmatch and pmatch options of regexec() are
917        ignored.
919    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
920        provided in case anyone wants to the the POSIX interface with UTF-8
921        strings.
923    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
924        C++ linking (needed for some HP-UX environments).
926    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
927        (unused parameter) and in the pcre_printint() function (omitted "default"
928        switch label when the default is to do nothing).
930    15. Added some code to make it possible, when PCRE is compiled as a C++
931        library, to replace subject pointers for pcre_exec() with a smart pointer
932        class, thus making it possible to process discontinuous strings.
934    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
935        much the same function. They were added by different people who were trying
936        to make PCRE easy to compile on non-Unix systems. It has been suggested
937        that PCRE_EXPORT be abolished now that there is more automatic apparatus
938        for compiling on Windows systems. I have therefore replaced it with
939        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
940        defaults to "extern" for C or "extern C" for C++, which works fine on
941        Unix-like systems. It is now possible to override the value of PCRE_DATA_
942        SCOPE with something explicit in config.h. In addition:
944        (a) pcreposix.h still had just "extern" instead of either of these macros;
945            I have replaced it with PCRE_DATA_SCOPE.
947        (b) Functions such as _pcre_xclass(), which are internal to the library,
948            but external in the C sense, all had PCRE_EXPORT in their definitions.
949            This is apparently wrong for the Windows case, so I have removed it.
950            (It makes no difference on Unix-like systems.)
952    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
953        of recursive calls to match(). This is different to MATCH_LIMIT because
954        that limits the total number of calls to match(), not all of which increase
955        the depth of recursion. Limiting the recursion depth limits the amount of
956        stack (or heap if NO_RECURSE is set) that is used. The default can be set
957        when PCRE is compiled, and changed at run time. A patch from Google adds
958        this functionality to the C++ interface.
960    18. Changes to the handling of Unicode character properties:
962        (a) Updated the table to Unicode 4.1.0.
964        (b) Recognize characters that are not in the table as "Cn" (undefined).
966        (c) I revised the way the table is implemented to a much improved format
967            which includes recognition of ranges. It now supports the ranges that
968            are defined in UnicodeData.txt, and it also amalgamates other
969            characters into ranges. This has reduced the number of entries in the
970            table from around 16,000 to around 3,000, thus reducing its size
971            considerably. I realized I did not need to use a tree structure after
972            all - a binary chop search is just as efficient. Having reduced the
973            number of entries, I extended their size from 6 bytes to 8 bytes to
974            allow for more data.
976        (d) Added support for Unicode script names via properties such as \p{Han}.
978    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
979        matching that character.
981    20. When matching a repeated Unicode property with a minimum greater than zero,
982        (for example \pL{2,}), PCRE could look past the end of the subject if it
983        reached it while seeking the minimum number of characters. This could
984        happen only if some of the characters were more than one byte long, because
985        there is a check for at least the minimum number of bytes.
987    21. Refactored the implementation of \p and \P so as to be more general, to
988        allow for more different types of property in future. This has changed the
989        compiled form incompatibly. Anybody with saved compiled patterns that use
990        \p or \P will have to recompile them.
992    22. Added "Any" and "L&" to the supported property types.
994    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
995        but give a compile time error if the value is greater than 0xff.
997    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
998        accidentally not being installed or uninstalled.
1000    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1001        made were to insert the current release number. This seemed silly, because
1002        it made things harder for people building PCRE on systems that don't run
1003        "configure". I have turned pcre.h into a distributed file, no longer built
1004        by "configure", with the version identification directly included. There is
1005        no longer a pcre.h.in file.
1007        However, this change necessitated a change to the pcre-config script as
1008        well. It is built from pcre-config.in, and one of the substitutions was the
1009        release number. I have updated configure.ac so that ./configure now finds
1010        the release number by grepping pcre.h.
1012    26. Added the ability to run the tests under valgrind.
1015    Version 6.4 05-Sep-05
1016    ---------------------
1018     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1019        "--" to be printed when multiple files were scanned, even when none of the
1020        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1021        consider it to be a bug, and have restored the previous behaviour.
1023     2. A couple of code tidies to get rid of compiler warnings.
1025     3. The pcretest program used to cheat by referring to symbols in the library
1026        whose names begin with _pcre_. These are internal symbols that are not
1027        really supposed to be visible externally, and in some environments it is
1028        possible to suppress them. The cheating is now confined to including
1029        certain files from the library's source, which is a bit cleaner.
1031     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1032        file's purpose clearer.
1034     5. Reorganized pcre_ucp_findchar().
1037    Version 6.3 15-Aug-05
1038    ---------------------
1040     1. The file libpcre.pc.in did not have general read permission in the tarball.
1042     2. There were some problems when building without C++ support:
1044        (a) If C++ support was not built, "make install" and "make test" still
1045            tried to test it.
1047        (b) There were problems when the value of CXX was explicitly set. Some
1048            changes have been made to try to fix these, and ...
1050        (c) --disable-cpp can now be used to explicitly disable C++ support.
1052        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1053            backslash in a target when C++ was disabled. This confuses some
1054            versions of "make", apparently. Using an intermediate variable solves
1055            this. (Same for CPP_LOBJ.)
1057     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1058        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1059        necessary on certain architectures.
1061     4. Added a setting of -export-symbols-regex to the link command to remove
1062        those symbols that are exported in the C sense, but actually are local
1063        within the library, and not documented. Their names all begin with
1064        "_pcre_". This is not a perfect job, because (a) we have to except some
1065        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1066        available (and never for static libraries). I have made a note to try to
1067        find a way round (a) in the future.
1070    Version 6.2 01-Aug-05
1071    ---------------------
1073     1. There was no test for integer overflow of quantifier values. A construction
1074        such as {1111111111111111} would give undefined results. What is worse, if
1075        a minimum quantifier for a parenthesized subpattern overflowed and became
1076        negative, the calculation of the memory size went wrong. This could have
1077        led to memory overwriting.
1079     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1081     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1082        operating environments where this matters.
1084     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1085        PCRE options from within the C++ wrapper.
1087     5. Named capturing subpatterns were not being correctly counted when a pattern
1088        was compiled. This caused two problems: (a) If there were more than 100
1089        such subpatterns, the calculation of the memory needed for the whole
1090        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1091        back references of the form \12, where the number was greater than 9, were
1092        not recognized as back references, even though there were sufficient
1093        previous subpatterns.
1095     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1096        versions of gcc, e.g. 2.95.4.
1099    Version 6.1 21-Jun-05
1100    ---------------------
1102     1. There was one reference to the variable "posix" in pcretest.c that was not
1103        surrounded by "#if !defined NOPOSIX".
1105     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1106        the cross-check on the old pcre_info() function, for the benefit of the
1107        cut-down version of PCRE that is currently imported into Exim.
1109     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1110        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1111        patterns that start (?i) but I don't think that matters. The use of (?i) is
1112        just an example; this all applies to the other options as well.
1114     4. Since libtool seems to echo the compile commands it is issuing, the output
1115        from "make" can be reduced a bit by putting "@" in front of each libtool
1116        compile command.
1118     5. Patch from the folks at Google for configure.in to be a bit more thorough
1119        in checking for a suitable C++ installation before trying to compile the
1120        C++ stuff. This should fix a reported problem when a compiler was present,
1121        but no suitable headers.
1123     6. The man pages all had just "PCRE" as their title. I have changed them to
1124        be the relevant file name. I have also arranged that these names are
1125        retained in the file doc/pcre.txt, which is a concatenation in text format
1126        of all the man pages except the little individual ones for each function.
1128     7. The NON-UNIX-USE file had not been updated for the different set of source
1129        files that come with release 6. I also added a few comments about the C++
1130        wrapper.
1133    Version 6.0 07-Jun-05
1134    ---------------------
1136     1. Some minor internal re-organization to help with my DFA experiments.
1138     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1139        didn't matter for the library itself when fully configured, but did matter
1140        when compiling without UCP support, or within Exim, where the ucp files are
1141        not imported.
1143     3. Refactoring of the library code to split up the various functions into
1144        different source modules. The addition of the new DFA matching code (see
1145        below) to a single monolithic source would have made it really too
1146        unwieldy, quite apart from causing all the code to be include in a
1147        statically linked application, when only some functions are used. This is
1148        relevant even without the DFA addition now that patterns can be compiled in
1149        one application and matched in another.
1151        The downside of splitting up is that there have to be some external
1152        functions and data tables that are used internally in different modules of
1153        the library but which are not part of the API. These have all had their
1154        names changed to start with "_pcre_" so that they are unlikely to clash
1155        with other external names.
1157     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1158        a different (DFA) algorithm. Although it is slower than the original
1159        function, it does have some advantages for certain types of matching
1160        problem.
1162     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1163        including restarting after a partial match.
1165     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1166        defined when compiling for Windows was sent to me. I have put it into the
1167        code, though I have no means of testing or verifying it.
1169     7. Added the pcre_refcount() auxiliary function.
1171     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1172        match before or at the first newline in the subject string. In pcretest,
1173        the /f option on a pattern can be used to set this.
1175     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1176        would behave wrongly. This has been present in PCRE since release 4.0.
1178    10. A number of changes to the pcregrep command:
1180        (a) Refactored how -x works; insert ^(...)$ instead of setting
1181            PCRE_ANCHORED and checking the length, in preparation for adding
1182            something similar for -w.
1184        (b) Added the -w (match as a word) option.
1186        (c) Refactored the way lines are read and buffered so as to have more
1187            than one at a time available.
1189        (d) Implemented a pcregrep test script.
1191        (e) Added the -M (multiline match) option. This allows patterns to match
1192            over several lines of the subject. The buffering ensures that at least
1193            8K, or the rest of the document (whichever is the shorter) is available
1194            for matching (and similarly the previous 8K for lookbehind assertions).
1196        (f) Changed the --help output so that it now says
1198              -w, --word-regex(p)
1200            instead of two lines, one with "regex" and the other with "regexp"
1201            because that confused at least one person since the short forms are the
1202            same. (This required a bit of code, as the output is generated
1203            automatically from a table. It wasn't just a text change.)
1205        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1206            option but starts with a hyphen. Could be a pattern or a path name
1207            starting with a hyphen, for instance.
1209        (h) "-" can be given as a file name to represent stdin.
1211        (i) When file names are being printed, "(standard input)" is used for
1212            the standard input, for compatibility with GNU grep. Previously
1213            "<stdin>" was used.
1215        (j) The option --label=xxx can be used to supply a name to be used for
1216            stdin when file names are being printed. There is no short form.
1218        (k) Re-factored the options decoding logic because we are going to add
1219            two more options that take data. Such options can now be given in four
1220            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1222        (l) Added the -A, -B, and -C options for requesting that lines of context
1223            around matches be printed.
1225        (m) Added the -L option to print the names of files that do not contain
1226            any matching lines, that is, the complement of -l.
1228        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1229            continue to scan other files.
1231        (o) The -s option was incorrectly implemented. For compatibility with other
1232            greps, it now suppresses the error message for a non-existent or non-
1233            accessible file (but not the return code). There is a new option called
1234            -q that suppresses the output of matching lines, which was what -s was
1235            previously doing.
1237        (p) Added --include and --exclude options to specify files for inclusion
1238            and exclusion when recursing.
1240    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1241        Hopefully, it now does.
1243    12. Missing cast in pcre_study().
1245    13. Added an "uninstall" target to the makefile.
1247    14. Replaced "extern" in the function prototypes in Makefile.in with
1248        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1249        world, but is set differently for Windows.
1251    15. Added a second compiling function called pcre_compile2(). The only
1252        difference is that it has an extra argument, which is a pointer to an
1253        integer error code. When there is a compile-time failure, this is set
1254        non-zero, in addition to the error test pointer being set to point to an
1255        error message. The new argument may be NULL if no error number is required
1256        (but then you may as well call pcre_compile(), which is now just a
1257        wrapper). This facility is provided because some applications need a
1258        numeric error indication, but it has also enabled me to tidy up the way
1259        compile-time errors are handled in the POSIX wrapper.
1261    16. Added VPATH=.libs to the makefile; this should help when building with one
1262        prefix path and installing with another. (Or so I'm told by someone who
1263        knows more about this stuff than I do.)
1265    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1266        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1267        match everything, including newlines. This is not POSIX-compatible, but
1268        somebody wanted the feature. From pcretest it can be activated by using
1269        both the P and the s flags.
1271    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1273    19. libpcre.pc was being incorrectly installed as executable.
1275    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1276        it now also looks for '\r' so that it will work unmodified on Windows.
1278    21. Added Google's contributed C++ wrapper to the distribution.
1280    22. Added some untidy missing memory free() calls in pcretest, to keep
1281        Electric Fence happy when testing.
1285    Version 5.0 13-Sep-04
1286    ---------------------
1288     1. Internal change: literal characters are no longer packed up into items
1289        containing multiple characters in a single byte-string. Each character
1290        is now matched using a separate opcode. However, there may be more than one
1291        byte in the character in UTF-8 mode.
1293     2. The pcre_callout_block structure has two new fields: pattern_position and
1294        next_item_length. These contain the offset in the pattern to the next match
1295        item, and its length, respectively.
1297     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1298        insertion of callouts before each pattern item. Added the /C option to
1299        pcretest to make use of this.
1301     4. On the advice of a Windows user, the lines
1303          #if defined(_WIN32) || defined(WIN32)
1304          _setmode( _fileno( stdout ), 0x8000 );
1305          #endif  /* defined(_WIN32) || defined(WIN32) */
1307        have been added to the source of pcretest. This apparently does useful
1308        magic in relation to line terminators.
1310     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1311        for the benefit of those environments where the "b" makes a difference.
1313     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1314        to know about it. I have put a hack into configure.in that adds in code
1315        to set GCC=yes if CC=icc. This seems to end up at a point in the
1316        generated configure script that is early enough to affect the setting of
1317        compiler options, which is what is needed, but I have no means of testing
1318        whether it really works. (The user who reported this had patched the
1319        generated configure script, which of course I cannot do.)
1321        LATER: After change 22 below (new libtool files), the configure script
1322        seems to know about icc (and also ecc). Therefore, I have commented out
1323        this hack in configure.in.
1325     7. Added support for pkg-config (2 patches were sent in).
1327     8. Negated POSIX character classes that used a combination of internal tables
1328        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1329        [[:^ascii]]. Typically, they would match almost any characters. The other
1330        POSIX classes were not broken in this way.
1332     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1333        to find the match, as PCRE was deluded into thinking that the match had to
1334        start at the start point or following a newline. The same bug applied to
1335        patterns with negative forward assertions or any backward assertions
1336        preceding ".*" at the start, unless the pattern required a fixed first
1337        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1339    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1340        starting at the last subject character, bytes beyond the end of the subject
1341        string were read.
1343    11. Renamed the variable "class" as "classbits" to make life easier for C++
1344        users. (Previously there was a macro definition, but it apparently wasn't
1345        enough.)
1347    12. Added the new field "tables" to the extra data so that tables can be passed
1348        in at exec time, or the internal tables can be re-selected. This allows
1349        a compiled regex to be saved and re-used at a later time by a different
1350        program that might have everything at different addresses.
1352    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1353        -R library as well as a -L library.
1355    14. The debugging options of pcretest (-d on the command line or D on a
1356        pattern) showed incorrect output for anything following an extended class
1357        that contained multibyte characters and which was followed by a quantifier.
1359    15. Added optional support for general category Unicode character properties
1360        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1361        support. It adds about 90K to the size of the library. The meanings of the
1362        inbuilt class escapes such as \d and \s have NOT been changed.
1364    16. Updated pcredemo.c to include calls to free() to release the memory for the
1365        compiled pattern.
1367    17. The generated file chartables.c was being created in the source directory
1368        instead of in the building directory. This caused the build to fail if the
1369        source directory was different from the building directory, and was
1370        read-only.
1372    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1373        file. No doubt somebody will tell me if they don't make sense... Also added
1374        Dan Mooney's comments about building on OpenVMS.
1376    19. Added support for partial matching via the PCRE_PARTIAL option for
1377        pcre_exec() and the \P data escape in pcretest.
1379    20. Extended pcretest with 3 new pattern features:
1381        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1382              write the compiled pattern to the file whose name is "rest-of-line".
1383              This is a straight binary dump of the data, with the saved pointer to
1384              the character tables forced to be NULL. The study data, if any, is
1385              written too. After writing, pcretest reads a new pattern.
1387        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1388              compiled pattern from the given file. There must not be any
1389              occurrences of "<" in the file name (pretty unlikely); if there are,
1390              pcretest will instead treat the initial "<" as a pattern delimiter.
1391              After reading in the pattern, pcretest goes on to read data lines as
1392              usual.
1394        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1395              and 16-bit fields in a compiled pattern, to simulate a pattern that
1396              was compiled on a host of opposite endianness.
1398    21. The pcre-exec() function can now cope with patterns that were compiled on
1399        hosts of opposite endianness, with this restriction:
1401          As for any compiled expression that is saved and used later, the tables
1402          pointer field cannot be preserved; the extra_data field in the arguments
1403          to pcre_exec() should be used to pass in a tables address if a value
1404          other than the default internal tables were used at compile time.
1406    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1407        now diagnosed as an error. Previously, most of the time, a negative number
1408        would have been treated as zero, but if in addition "ovector" was passed as
1409        NULL, a crash could occur.
1411    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1412        new versions from the libtool 1.5 distribution (the last one is a copy of
1413        a file called libtool.m4). This seems to have fixed the need to patch
1414        "configure" to support Darwin 1.3 (which I used to do). However, I still
1415        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1416        workstation).
1418    24. Changed the PCRE licence to be the more standard "BSD" licence.
1421    Version 4.5 01-Dec-03
1422    ---------------------
1424     1. There has been some re-arrangement of the code for the match() function so
1425        that it can be compiled in a version that does not call itself recursively.
1426        Instead, it keeps those local variables that need separate instances for
1427        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1428        needs to "recurse". Keeping track of where control must go is done by means
1429        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1430        hide most of the details from the main code, and operates only if
1431        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1432        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1433        operating.
1435        To make it easier for callers to provide specially tailored get/free
1436        functions for this usage, two new functions, pcre_stack_malloc, and
1437        pcre_stack_free, are used. They are always called in strict stacking order,
1438        and the size of block requested is always the same.
1440        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1441        PCRE has been compiled to use the stack or the heap for recursion. The
1442        -C option of pcretest uses this to show which version is compiled.
1444        A new data escape \S, is added to pcretest; it causes the amounts of store
1445        obtained and freed by both kinds of malloc/free at match time to be added
1446        to the output.
1448     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1449        what's available on my current Linux desktop machine.
1451     3. When matching a UTF-8 string, the test for a valid string at the start has
1452        been extended. If start_offset is not zero, PCRE now checks that it points
1453        to a byte that is the start of a UTF-8 character. If not, it returns
1454        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1455        this is necessary because there may be backward assertions in the pattern.
1456        When matching the same subject several times, it may save resources to use
1457        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1459     4. The code for checking the validity of UTF-8 strings has been tightened so
1460        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1461        containing "overlong sequences".
1463     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1464        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1465        should have been "&", but it just so happened that all the cases this let
1466        through by mistake were picked up later in the function.
1468     6. I had used a variable called "isblank" - this is a C99 function, causing
1469        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1471     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1472        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1473        so the version is shown; (c) stop "make test" echoing "./RunTest".
1475     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1477     9. The prototype for memmove() for systems that don't have it was using
1478        size_t, but the inclusion of the header that defines size_t was later. I've
1479        moved the #includes for the C headers earlier to avoid this.
1481    10. Added some adjustments to the code to make it easier to compiler on certain
1482        special systems:
1484          (a) Some "const" qualifiers were missing.
1485          (b) Added the macro EXPORT before all exported functions; by default this
1486              is defined to be empty.
1487          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1488              that it reads its output file name as an argument instead of writing
1489              to the standard output and assuming this can be redirected.
1491    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1492        class containing characters with values greater than 255, PCRE compilation
1493        went into a loop.
1495    12. A recursive reference to a subpattern that was within another subpattern
1496        that had a minimum quantifier of zero caused PCRE to crash. For example,
1497        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1498        recursion. If the recursively-called subpattern itself had a zero repeat,
1499        that was OK.
1501    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1502        buffer into which it was copied (for escape processing) was still set at
1503        1024, so long lines caused crashes.
1505    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1506        "internal error: code overflow...". This applied to any character class
1507        that was followed by a possessive quantifier.
1509    15. Modified the Makefile to add libpcre.la as a prerequisite for
1510        libpcreposix.la because I was told this is needed for a parallel build to
1511        work.
1513    16. If a pattern that contained .* following optional items at the start was
1514        studied, the wrong optimizing data was generated, leading to matching
1515        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1516        matching string must start with a or b or c. The correct conclusion for
1517        this pattern is that a match can start with any character.
1520    Version 4.4 13-Aug-03
1521    ---------------------
1523     1. In UTF-8 mode, a character class containing characters with values between
1524        127 and 255 was not handled correctly if the compiled pattern was studied.
1525        In fixing this, I have also improved the studying algorithm for such
1526        classes (slightly).
1528     2. Three internal functions had redundant arguments passed to them. Removal
1529        might give a very teeny performance improvement.
1531     3. Documentation bug: the value of the capture_top field in a callout is *one
1532        more than* the number of the hightest numbered captured substring.
1534     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1535        in incorrectly linking with a previously installed version. They now link
1536        explicitly with libpcre.la.
1538     5. configure.in no longer needs to recognize Cygwin specially.
1540     6. A problem in pcre.in for Windows platforms is fixed.
1542     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1543        pcretest, it used to include the size of the study block as part of its
1544        output. Unfortunately, the structure contains a field that has a different
1545        size on different hardware architectures. This meant that the tests that
1546        showed this size failed. As the block is currently always of a fixed size,
1547        this information isn't actually particularly useful in pcretest output, so
1548        I have just removed it.
1550     8. Three pre-processor statements accidentally did not start in column 1.
1551        Sadly, there are *still* compilers around that complain, even though
1552        standard C has not required this for well over a decade. Sigh.
1554     9. In pcretest, the code for checking callouts passed small integers in the
1555        callout_data field, which is a void * field. However, some picky compilers
1556        complained about the casts involved for this on 64-bit systems. Now
1557        pcretest passes the address of the small integer instead, which should get
1558        rid of the warnings.
1560    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1561        both compile and run time, and gives an error if an invalid UTF-8 sequence
1562        is found. There is a option for disabling this check in cases where the
1563        string is known to be correct and/or the maximum performance is wanted.
1565    11. In response to a bug report, I changed one line in Makefile.in from
1567            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1568        to
1569            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1571        to look similar to other lines, but I have no way of telling whether this
1572        is the right thing to do, as I do not use Windows. No doubt I'll get told
1573        if it's wrong...
1576    Version 4.3 21-May-03
1577    ---------------------
1579    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1580       Makefile.
1582    2. Some refactoring to improve the quality of the code:
1584       (i)   The utf8_table... variables are now declared "const".
1586       (ii)  The code for \cx, which used the "case flipping" table to upper case
1587             lower case letters, now just substracts 32. This is ASCII-specific,
1588             but the whole concept of \cx is ASCII-specific, so it seems
1589             reasonable.
1591       (iii) PCRE was using its character types table to recognize decimal and
1592             hexadecimal digits in the pattern. This is silly, because it handles
1593             only 0-9, a-f, and A-F, but the character types table is locale-
1594             specific, which means strange things might happen. A private
1595             table is now used for this - though it costs 256 bytes, a table is
1596             much faster than multiple explicit tests. Of course, the standard
1597             character types table is still used for matching digits in subject
1598             strings against \d.
1600       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1601             ending in _t are). So I've renamed it as ESC_tee.
1603    3. The first argument for regexec() in the POSIX wrapper should have been
1604       defined as "const".
1606    4. Changed pcretest to use malloc() for its buffers so that they can be
1607       Electric Fenced for debugging.
1609    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1610       to read one or more bytes before the start of the subject string. Often this
1611       had no effect on PCRE's behaviour, but in some circumstances it could
1612       provoke a segmentation fault.
1614    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1615       to try to read one or more bytes before the start of the subject string.
1617    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1618       UTF-8 support could misbehave in various ways if the subject string
1619       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1620       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1621       back over UTF-8 characters.)
1624    Version 4.2 14-Apr-03
1625    ---------------------
1627    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1629    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1630         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1631         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1632         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1633         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1634           and BUILD_EXEEXT
1635         Note: automatic setting of the BUILD variables is not yet working
1636         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1637           compile-time but not at link-time
1638         [LINK]: use for linking executables only
1639         make different versions for Windows and non-Windows
1640         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1641           libraries
1642         [LINK_FOR_BUILD]: new variable
1643         [OBJEXT]: use throughout
1644         [EXEEXT]: use throughout
1645         <winshared>: new target
1646         <wininstall>: new target
1647         <dftables.o>: use native compiler
1648         <dftables>: use native linker
1649         <install>: handle Windows platform correctly
1650         <clean>: ditto
1651         <check>: ditto
1652         copy DLL to top builddir before testing
1654       As part of these changes, -no-undefined was removed again. This was reported
1655       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1656       in any case.
1658    3. Some tidies to get rid of compiler warnings:
1660       . In the match_data structure, match_limit was an unsigned long int, whereas
1661         match_call_count was an int. I've made them both unsigned long ints.
1663       . In pcretest the fact that a const uschar * doesn't automatically cast to
1664         a void * provoked a warning.
1666       . Turning on some more compiler warnings threw up some "shadow" variables
1667         and a few more missing casts.
1669    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1670       option, a class that contained a single character with a value between 128
1671       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1673    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1674       option, a class that contained several characters, but with at least one
1675       whose value was between 128 and 255 caused PCRE to crash.
1678    Version 4.1 12-Mar-03
1679    ---------------------
1681    1. Compiling with gcc -pedantic found a couple of places where casts were
1682    needed, and a string in dftables.c that was longer than standard compilers are
1683    required to support.
1685    2. Compiling with Sun's compiler found a few more places where the code could
1686    be tidied up in order to avoid warnings.
1688    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1689    first of these names is deprecated in the latest Autoconf in favour of the name
1690    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1691    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1692    analogy I have changed it to CFLAGS_FOR_BUILD.
1694    4. Added -no-undefined to the linking command in the Makefile, because this is
1695    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1696    linking step for the pcreposix library.
1698    5. PCRE was failing to diagnose the case of two named groups with the same
1699    name.
1701    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1702    literal character that is needed in the subject for a match, and scans along to
1703    ensure that it is present before embarking on the full matching process. This
1704    saves time in cases of nested unlimited repeats that are never going to match.
1705    Problem: the scan can take a lot of time if the subject is very long (e.g.
1706    megabytes), thus penalizing straightforward matches. It is now done only if the
1707    amount of subject to be scanned is less than 1000 bytes.
1709    7. A lesser problem with the same optimization is that it was recording the
1710    first character of an anchored pattern as "needed", thus provoking a search
1711    right along the subject, even when the first match of the pattern was going to
1712    fail. The "needed" character is now not set for anchored patterns, unless it
1713    follows something in the pattern that is of non-fixed length. Thus, it still
1714    fulfils its original purpose of finding quick non-matches in cases of nested
1715    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1718    Version 4.0 17-Feb-03
1719    ---------------------
1721    1. If a comment in an extended regex that started immediately after a meta-item
1722    extended to the end of string, PCRE compiled incorrect data. This could lead to
1723    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1725    2. Moved to autoconf 2.53 and libtool 1.4.2.
1727    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1728    the special perltest8 script is no longer needed - all the tests can be run
1729    from a single perltest script.
1731    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1732    by \s. It has now been removed in PCRE. This means it isn't recognized as
1733    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1734    class [:space:] *does* include VT, thereby creating a mess.
1736    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1737    space and tab.
1739    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1740    its new features into the main test script, reducing the number of scripts.
1742    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1743    were backward compatible, and made the (?i) apply to the whole pattern, as if
1744    /i were given. Now it behaves more logically, and applies the option setting
1745    only to what follows. PCRE has been changed to follow suit. However, if it
1746    finds options settings right at the start of the pattern, it extracts them into
1747    the global options, as before. Thus, they show up in the info data.
1749    8. Added support for the \Q...\E escape sequence. Characters in between are
1750    treated as literals. This is slightly different from Perl in that $ and @ are
1751    also handled as literals inside the quotes. In Perl, they will cause variable
1752    interpolation. Note the following examples:
1754        Pattern            PCRE matches      Perl matches
1756        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1757        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1758        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1760    For compatibility with Perl, \Q...\E sequences are recognized inside character
1761    classes as well as outside them.
1763    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1764    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1765    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1766    signed/unsigned warnings.
1768    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1769    option for pcretest, so I've replaced it by a simple function that does just
1770    that job.
1772    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1773    "pcregrep -".
1775    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1776    Java package. This provides some syntactic sugar for simple cases of what my
1777    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1778    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1779    item, you can use this simplified notation. Note that only makes sense with
1780    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1781    greediness, whatever the setting of the PCRE_UNGREEDY option.
1783    13. A change of greediness default within a pattern was not taking effect at
1784    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1785    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1786    was abstracted outside.
1788    14. PCRE now supports the \G assertion. It is true when the current matching
1789    position is at the start point of the match. This differs from \A when the
1790    starting offset is non-zero. Used with the /g option of pcretest (or similar
1791    code), it works in the same way as it does for Perl's /g option. If all
1792    alternatives of a regex begin with \G, the expression is anchored to the start
1793    match position, and the "anchored" flag is set in the compiled expression.
1795    15. Some bugs concerning the handling of certain option changes within patterns
1796    have been fixed. These applied to options other than (?ims). For example,
1797    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1798    been the other way round. Some of this was related to change 7 above.
1800    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1801    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1802    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1803    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1805    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1806    mode. Unlike ".", it always matches newline, whatever the setting of
1807    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1808    assertions. Perl allows it, but it doesn't (in general) work because it can't
1809    calculate the length of the lookbehind. At least, that's the case for Perl
1810    5.8.0 - I've been told they are going to document that it doesn't work in
1811    future.
1813    18. Added an error diagnosis for escapes that PCRE does not support: these are
1814    \L, \l, \N, \P, \p, \U, \u, and \X.
1816    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1817    reading past the end of the pattern in cases such as /[abcd/.
1819    20. PCRE was getting more memory than necessary for patterns with classes that
1820    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1822    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1823    compiling PCRE for use with Virtual Pascal.
1825    22. Small fix to the Makefile to make it work properly if the build is done
1826    outside the source tree.
1828    23. Added a new extension: a condition to go with recursion. If a conditional
1829    subpattern starts with (?(R) the "true" branch is used if recursion has
1830    happened, whereas the "false" branch is used only at the top level.
1832    24. When there was a very long string of literal characters (over 255 bytes
1833    without UTF support, over 250 bytes with UTF support), the computation of how
1834    much memory was required could be incorrect, leading to segfaults or other
1835    strange effects.
1837    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1838    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1839    there was a subsequent back reference to those brackets. This meant that, for
1840    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1841    possible to check for precisely this case. All we can do is abandon the
1842    optimization if .* occurs inside capturing brackets when there are any back
1843    references whatsoever. (See below for a better fix that came later.)
1845    26. The handling of the optimization for finding the first character of a
1846    non-anchored pattern, and for finding a character that is required later in the
1847    match were failing in some cases. This didn't break the matching; it just
1848    failed to optimize when it could. The way this is done has been re-implemented.
1850    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1852    28. Added a new feature that provides some of the functionality that Perl
1853    provides with (?{...}). The facility is termed a "callout". The way it is done
1854    in PCRE is for the caller to provide an optional function, by setting
1855    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1856    global variable. By default it is unset, which disables all calling out. To get
1857    the function called, the regex must include (?C) at appropriate points. This
1858    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1859    This provides a means of identifying different callout points. When PCRE
1860    reaches such a point in the regex, if pcre_callout has been set, the external
1861    function is called. It is provided with data in a structure called
1862    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1863    matching continues; if it returns a non-zero value, the match at the current
1864    point fails. However, backtracking will occur if possible. [This was changed
1865    later and other features added - see item 49 below.]
1867    29. pcretest is upgraded to test the callout functionality. It provides a
1868    callout function that displays information. By default, it shows the start of
1869    the match and the current position in the text. There are some new data escapes
1870    to vary what happens:
1872        \C+         in addition, show current contents of captured substrings
1873        \C-         do not supply a callout function
1874        \C!n        return 1 when callout number n is reached
1875        \C!n!m      return 1 when callout number n is reached for the mth time
1877    30. If pcregrep was called with the -l option and just a single file name, it
1878    output "<stdin>" if a match was found, instead of the file name.
1880    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1881    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1882    pcre_exec(). This saves a malloc/free per call. The default value of
1883    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1884    when configuring.
1886    32. The default maximum size of a compiled pattern is 64K. There have been a
1887    few cases of people hitting this limit. The code now uses macros to handle the
1888    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1889    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1890    configuring. Tests 2 and 5 work only with 2-byte links because they output
1891    debugging information about compiled patterns.
1893    33. Internal code re-arrangements:
1895    (a) Moved the debugging function for printing out a compiled regex into
1896        its own source file (printint.c) and used #include to pull it into
1897        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1898        separate copies.
1900    (b) Defined the list of op-code names for debugging as a macro in
1901        internal.h so that it is next to the definition of the opcodes.
1903    (c) Defined a table of op-code lengths for simpler skipping along compiled
1904        code. This is again a macro in internal.h so that it is next to the
1905        definition of the opcodes.
1907    34. Added support for recursive calls to individual subpatterns, along the
1908    lines of Robin Houston's patch (but implemented somewhat differently).
1910    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1911    allow it to read and process whole directories in Win32. This code was
1912    contributed by Lionel Fourquaux; it has not been tested by me.
1914    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1915    used to name a group. Names consist of alphanumerics and underscores, and must
1916    be unique. Back references use the syntax (?P=name) and recursive calls use
1917    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1918    numbers. The function pcre_fullinfo() can be used after compilation to extract
1919    a name/number map. There are three relevant calls:
1921      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1922      PCRE_INFO_NAMECOUNT            yields the number of entries
1923      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1925    The map is a vector of fixed-size entries. The size of each entry depends on
1926    the length of the longest name used. The first two bytes of each entry are the
1927    group number, most significant byte first. There follows the corresponding
1928    name, zero terminated. The names are in alphabetical order.
1930    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1931    case instead of 255. Making it the same both with and without UTF-8 support
1932    means that the same test output works with both.
1934    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1935    calling malloc() with a zero argument.
1937    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1938    optimization. I've improved things by keeping a bitmap of backreferences with
1939    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1940    fact referenced, the optimization can be applied. It is unlikely that a
1941    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1942    the match to follow \n) will appear inside brackets with a number greater than
1943    31, but if it does, any back reference > 31 suppresses the optimization.
1945    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1946    of disabling numbered capturing parentheses. Any opening parenthesis that is
1947    not followed by ? behaves as if it were followed by ?: but named parentheses
1948    can still be used for capturing (and they will acquire numbers in the usual
1949    way).
1951    41. Redesigned the return codes from the match() function into yes/no/error so
1952    that errors can be passed back from deep inside the nested calls. A malloc
1953    failure while inside a recursive subpattern call now causes the
1954    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1956    42. It is now possible to set a limit on the number of times the match()
1957    function is called in a call to pcre_exec(). This facility makes it possible to
1958    limit the amount of recursion and backtracking, though not in a directly
1959    obvious way, because the match() function is used in a number of different
1960    circumstances. The count starts from zero for each position in the subject
1961    string (for non-anchored patterns). The default limit is, for compatibility, a
1962    large number, namely 10 000 000. You can change this in two ways:
1964    (a) When configuring PCRE before making, you can use --with-match-limit=n
1965        to set a default value for the compiled library.
1967    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1968        a different value is set. See 45 below.
1970    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1972    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1973    of things that can be changed at compile time. The first argument specifies
1974    what is wanted and the second points to where the information is to be placed.
1975    The current list of available information is:
1977      PCRE_CONFIG_UTF8
1979    The output is an integer that is set to one if UTF-8 support is available;
1980    otherwise it is set to zero.
1984    The output is an integer that it set to the value of the code that is used for
1985    newline. It is either LF (10) or CR (13).
1989    The output is an integer that contains the number of bytes used for internal
1990    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1994    The output is an integer that contains the threshold above which the POSIX
1995    interface uses malloc() for output vectors. See item 31 above.
1999    The output is an unsigned integer that contains the default limit of the number
2000    of match() calls in a pcre_exec() execution. See 42 above.
2002    44. pcretest has been upgraded by the addition of the -C option. This causes it
2003    to extract all the available output from the new pcre_config() function, and to
2004    output it. The program then exits immediately.
2006    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2007    order to support additional features. One way would have been to define
2008    pcre_exec2() (for example) with extra arguments, but this would not have been
2009    extensible, and would also have required all calls to the original function to
2010    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2011    is used for passing in "extra" data from pcre_study().
2013    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2014    contains the following fields:
2016      flags         a bitmap indicating which of the following fields are set
2017      study_data    opaque data from pcre_study()
2018      match_limit   a way of specifying a limit on match() calls for a specific
2019                      call to pcre_exec()
2020      callout_data  data for callouts (see 49 below)
2022    The flag bits are also defined in pcre.h, and are
2028    The pcre_study() function now returns one of these new pcre_extra blocks, with
2029    the actual study data pointed to by the study_data field, and the
2030    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2031    before. That is, this change is entirely upwards-compatible and requires no
2032    change to existing code.
2034    If you want to pass in additional data to pcre_exec(), you can either place it
2035    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2036    block.
2038    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2039    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2040    times with different match limits, until it finds the minimum value needed for
2041    pcre_exec() to complete. The value is then output. This can be instructive; for
2042    most simple matches the number is quite small, but for pathological cases it
2043    gets very large very quickly.
2045    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2046    returns the size of the data block pointed to by the study_data field in a
2047    pcre_extra block, that is, the value that was passed as the argument to
2048    pcre_malloc() when PCRE was getting memory in which to place the information
2049    created by pcre_study(). The fourth argument should point to a size_t variable.
2050    pcretest has been extended so that this information is shown after a successful
2051    pcre_study() call when information about the compiled regex is being displayed.
2053    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2054    because what follows is always an absolute path. (Later: it turns out that this
2055    is more than cosmetic for MinGW, because it doesn't like empty path
2056    components.)
2058    49. Some changes have been made to the callout feature (see 28 above):
2060    (i)  A callout function now has three choices for what it returns:
2062           0  =>  success, carry on matching
2063         > 0  =>  failure at this point, but backtrack if possible
2064         < 0  =>  serious error, return this value from pcre_exec()
2066         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2067         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2068         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2069         use by callout functions. It will never be used by PCRE itself.
2071    (ii) The pcre_extra structure (see 45 above) has a void * field called
2072         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2073         pcre_callout_block structure has a field of the same name. The contents of
2074         the field passed in the pcre_extra structure are passed to the callout
2075         function in the corresponding field in the callout block. This makes it
2076         easier to use the same callout-containing regex from multiple threads. For
2077         testing, the pcretest program has a new data escape
2079           \C*n        pass the number n (may be negative) as callout_data
2081         If the callout function in pcretest receives a non-zero value as
2082         callout_data, it returns that value.
2084    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2085    there were some redundant $(CFLAGS) in commands that are now specified as
2086    $(LINK), which already includes $(CFLAGS).
2088    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2089    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2090    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2091    one-byte characters throughout. Note that case-insensitive matching applies
2092    only to characters whose values are less than 256. PCRE doesn't support the
2093    notion of cases for higher-valued characters.
2095    (i)   A character class whose characters are all within 0-255 is handled as
2096          a bit map, and the map is inverted for negative classes. Previously, a
2097          character > 255 always failed to match such a class; however it should
2098          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2100    (ii)  A negated character class with a single character < 255 is coded as
2101          "not this character" (OP_NOT). This wasn't working properly when the test
2102          character was multibyte, either singly or repeated.
2104    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2105          mode, for example: \x{100}{2,3}.
2107    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2108          singly or repeated) now correctly test multibyte characters. However,
2109          PCRE doesn't recognize any characters with values greater than 255 as
2110          digits, spaces, or word characters. Such characters always match \D, \S,
2111          and \W, and never match \d, \s, or \w.
2113    (v)   Classes may now contain characters and character ranges with values
2114          greater than 255. For example: [ab\x{100}-\x{400}].
2116    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2117          PCRE in UTF-8 mode.
2119    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2120    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2121    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2122    value.)
2124    53. The single man page has become too large. I have therefore split it up into
2125    a number of separate man pages. These also give rise to individual HTML pages;
2126    these are now put in a separate directory, and there is an index.html page that
2127    lists them all. Some hyperlinking between the pages has been installed.
2129    54. Added convenience functions for handling named capturing parentheses.
2131    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2132    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2133    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2134    are faulted.
2136    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2137    calling configure. These values are used when compiling the dftables.c program
2138    which is run to generate the source of the default character tables. They
2139    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2140    you will need to set these values.
2142    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2145    Version 3.9 02-Jan-02
2146    ---------------------
2148    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2150    2. If --disable-static was given, the building process failed when trying to
2151    build pcretest and pcregrep. (For some reason it was using libtool to compile
2152    them, which is not right, as they aren't part of the library.)
2155    Version 3.8 18-Dec-01
2156    ---------------------
2158    1. The experimental UTF-8 code was completely screwed up. It was packing the
2159    bytes in the wrong order. How dumb can you get?
2162    Version 3.7 29-Oct-01
2163    ---------------------
2165    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2166    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2167    this didn't happen under Solaris 8, where I normally test things.
2169    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2170    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2171    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2172    this fix an hour or so after the initial 3.7 release.)
2175    Version 3.6 23-Oct-01
2176    ---------------------
2178    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2179    offsets passed as NULL with zero offset count.
2181    2. The config.guess and config.sub files had not been updated when I moved to
2182    the latest autoconf.
2185    Version 3.5 15-Aug-01
2186    ---------------------
2188    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2189    had been forgotten.
2191    2. By using declared but undefined structures, we can avoid using "void"
2192    definitions in pcre.h while keeping the internal definitions of the structures
2193    private.
2195    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2196    user point of view, this means that both static and shared libraries are built
2197    by default, but this can be individually controlled. More of the work of
2198    handling this static/shared cases is now inside libtool instead of PCRE's make
2199    file.
2201    4. The pcretest utility is now installed along with pcregrep because it is
2202    useful for users (to test regexs) and by doing this, it automatically gets
2203    relinked by libtool. The documentation has been turned into a man page, so
2204    there are now .1, .txt, and .html versions in /doc.
2206    5. Upgrades to pcregrep:
2207       (i)   Added long-form option names like gnu grep.
2208       (ii)  Added --help to list all options with an explanatory phrase.
2209       (iii) Added -r, --recursive to recurse into sub-directories.
2210       (iv)  Added -f, --file to read patterns from a file.
2212    6. pcre_exec() was referring to its "code" argument before testing that
2213    argument for NULL (and giving an error if it was NULL).
2215    7. Upgraded Makefile.in to allow for compiling in a different directory from
2216    the source directory.
2218    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2219    options bits, the pointer it was passed was to an int instead of to an unsigned
2220    long int. This mattered only on 64-bit systems.
2222    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2223    generated) instead of pcre.in, which it its source. Also made the same change
2224    in several of the .c files.
2226    10. A new release of gcc defines printf() as a macro, which broke pcretest
2227    because it had an ifdef in the middle of a string argument for printf(). Fixed
2228    by using separate calls to printf().
2230    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2231    script, to force use of CR or LF instead of \n in the source. On non-Unix
2232    systems, the value can be set in config.h.
2234    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2235    absolute limit. Changed the text of the error message to make this clear, and
2236    likewise updated the man page.
2238    13. The limit of 99 on the number of capturing subpatterns has been removed.
2239    The new limit is 65535, which I hope will not be a "real" limit.
2242    Version 3.4 22-Aug-00
2243    ---------------------
2245    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2247    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2250    Version 3.3 01-Aug-00
2251    ---------------------
2253    1. If an octal character was given, but the value was greater than \377, it
2254    was not getting masked to the least significant bits, as documented. This could
2255    lead to crashes in some systems.
2257    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2258    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2260    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2261    These just pass their arguments on to (pcre_free)(), but they are provided
2262    because some uses of PCRE bind it to non-C systems that can call its functions,
2263    but cannot call free() or pcre_free() directly.
2265    4. Add "make test" as a synonym for "make check". Corrected some comments in
2266    the Makefile.
2268    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2269    Makefile.
2271    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2272    command called pgrep for grepping around the active processes.
2274    7. Added the beginnings of support for UTF-8 character strings.
2276    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2277    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2278    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2279    out for the ar command.)
2282    Version 3.2 12-May-00
2283    ---------------------
2285    This is purely a bug fixing release.
2287    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2288    of ZA. This was just one example of several cases that could provoke this bug,
2289    which was introduced by change 9 of version 2.00. The code for breaking
2290    infinite loops after an iteration that matches an empty string was't working
2291    correctly.
2293    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2294    when matched against abbab (for example). After matching an empty string, it
2295    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2296    caused it to match further down the string than it should.
2298    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2299    was there because it doesn't seem to be needed, and it causes trouble on some
2300    systems, as it is not a Standard C header. It has been removed.
2302    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2303    were reported on the Macintosh. The changes were from
2305      while ((c = *(++ptr)) != 0 && c != '\n');
2306    to
2307      while ((c = *(++ptr)) != 0 && c != '\n') ;
2309    Totally extraordinary, but if that's what it takes...
2311    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2312    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2313    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2314    assumes the way PCRE uses memmove() (always moving upwards).
2316    6. PCRE is being used in one environment where strchr() is not available. There
2317    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2318    faster code anyway.
2321    Version 3.1 09-Feb-00
2322    ---------------------
2324    The only change in this release is the fixing of some bugs in Makefile.in for
2325    the "install" target:
2327    (1) It was failing to install pcreposix.h.
2329    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2332    Version 3.0 01-Feb-00
2333    ---------------------
2335    1. Add support for the /+ modifier to perltest (to output $` like it does in
2336    pcretest).
2338    2. Add support for the /g modifier to perltest.
2340    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2341    matches null strings.
2343    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2344    pattern. Perl treats empty patterns specially - it reuses the most recent
2345    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2346    effect.
2348    5. The POSIX interface was broken in that it was just handing over the POSIX
2349    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2350    required a bigger vector, with some working space on the end. This means that
2351    the POSIX wrapper now has to get and free some memory, and copy the results.
2353    6. Added some simple autoconf support, placing the test data and the
2354    documentation in separate directories, re-organizing some of the
2355    information files, and making it build pcre-config (a GNU standard). Also added
2356    libtool support for building PCRE as a shared library, which is now the
2357    default.
2359    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2360    09 are not valid octal constants. Single digits will be used for minor values
2361    less than 10.
2363    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2364    existing programs that set these in the POSIX interface can use PCRE without
2365    modification.
2367    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2368    return all that pcre_info() returns, plus additional data. The pcre_info()
2369    function is retained for compatibility, but is considered to be obsolete.
2371    10. Added experimental recursion feature (?R) to handle one common case that
2372    Perl 5.6 will be able to do with (?p{...}).
2374    11. Added support for POSIX character classes like [:alpha:], which Perl is
2375    adopting.
2378    Version 2.08 31-Aug-99
2379    ----------------------
2381    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2382    trying to match at the startoffset position, but instead was moving forward to
2383    the next newline as if a previous match had failed.
2385    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2386    and could get into a loop if a null string was matched other than at the start
2387    of the subject.
2389    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2390    be distinguished at compile time, and for completeness also added PCRE_DATE.
2392    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2393    in GnuWin32 environments.
2396    Version 2.07 29-Jul-99
2397    ----------------------
2399    1. The documentation is now supplied in plain text form and HTML as well as in
2400    the form of man page sources.
2402    2. C++ compilers don't like assigning (void *) values to other pointer types.
2403    In particular this affects malloc(). Although there is no problem in Standard
2404    C, I've put in casts to keep C++ compilers happy.
2406    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2407    should be (const char *).
2409    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2410    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2411    However, I haven't made this a standard facility. The documentation doesn't
2412    mention it, and the Makefile doesn't support it.
2414    5. The Makefile now contains an "install" target, with editable destinations at
2415    the top of the file. The pcretest program is not installed.
2417    6. pgrep -V now gives the PCRE version number and date.
2419    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2420    causing the entire string to be ignored, instead of just the last character.
2422    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2423    non-matching string, it can take a very, very long time, even for strings of
2424    quite modest length, because of the nested recursion. PCRE now does better in
2425    some of these cases. It does this by remembering the last required literal
2426    character in the pattern, and pre-searching the subject to ensure it is present
2427    before running the real match. In other words, it applies a heuristic to detect
2428    some types of certain failure quickly, and in the above example, if presented
2429    with a string that has no trailing " it gives "no match" very quickly.
2431    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2432    other alternatives are tried instead.
2435    Version 2.06 09-Jun-99
2436    ----------------------
2438    1. Change pcretest's output for amount of store used to show just the code
2439    space, because the remainder (the data block) varies in size between 32-bit and
2440    64-bit systems.
2442    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2443    start matching at. This allows lookbehinds to work when searching for multiple
2444    occurrences in a string.
2446    3. Added additional options to pcretest for testing multiple occurrences:
2448       /+   outputs the rest of the string that follows a match
2449       /g   loops for multiple occurrences, using the new startoffset argument
2450       /G   loops for multiple occurrences by passing an incremented pointer
2452    4. PCRE wasn't doing the "first character" optimization for patterns starting
2453    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2454    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2455    the letter 'x'. On long subject strings, this gives a significant speed-up.
2458    Version 2.05 21-Apr-99
2459    ----------------------
2461    1. Changed the type of magic_number from int to long int so that it works
2462    properly on 16-bit systems.
2464    2. Fixed a bug which caused patterns starting with .* not to work correctly
2465    when the subject string contained newline characters. PCRE was assuming
2466    anchoring for such patterns in all cases, which is not correct because .* will
2467    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2468    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2469    must be retried after every newline in the subject.
2472    Version 2.04 18-Feb-99
2473    ----------------------
2475    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2476    computation of the store needed to hold the pattern was incorrect (too large).
2477    If such patterns were nested a few deep, this could multiply and become a real
2478    problem.
2480    2. Added /M option to pcretest to show the memory requirement of a specific
2481    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2483    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2484    compiled in such a way that the backtracking after subsequent failure was
2485    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2486    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2489    Version 2.03 02-Feb-99
2490    ----------------------
2492    1. Fixed typo and small mistake in man page.
2494    2. Added 4th condition (GPL supersedes if conflict) and created separate
2495    LICENCE file containing the conditions.
2497    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2498    Perl, that is the internal \ allows the delimiter to be included in the
2499    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2500    the final delimiter, add \ to the end of the pattern (to test the error).
2502    4. Added the convenience functions for extracting substrings after a successful
2503    match. Updated pcretest to make it able to test these functions.
2506  Version 2.02 14-Jan-99  Version 2.02 14-Jan-99
2507  ----------------------  ----------------------

Removed from v.27  
changed lines
  Added in v.217

  ViewVC Help
Powered by ViewVC 1.1.5