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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.3 05-Jul-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.
74    Version 7.2 19-Jun-07
75    ---------------------
77     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
78        which is apparently normally available under Windows.
80     2. Re-jig the pcregrep tests with different newline settings in an attempt
81        to make them independent of the local environment's newline setting.
83     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
85     4. Some of the "internals" tests were previously cut out when the link size
86        was not 2, because the output contained actual offsets. The recent new
87        "Z" feature of pcretest means that these can be cut out, making the tests
88        usable with all link sizes.
90     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
91        stack recursion. This gives a massive performance boost under BSD, but just
92        a small improvement under Linux. However, it saves one field in the frame
93        in all cases.
95     6. Added more features from the forthcoming Perl 5.10:
97        (a) (?-n) (where n is a string of digits) is a relative subroutine or
98            recursion call. It refers to the nth most recently opened parentheses.
100        (b) (?+n) is also a relative subroutine call; it refers to the nth next
101            to be opened parentheses.
103        (c) Conditions that refer to capturing parentheses can be specified
104            relatively, for example, (?(-2)... or (?(+3)...
106        (d) \K resets the start of the current match so that everything before
107            is not part of it.
109        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
111        (f) \g{name} is another synonym - part of Perl 5.10's unification of
112            reference syntax.
114        (g) (?| introduces a group in which the numbering of parentheses in each
115            alternative starts with the same number.
117        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
119     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
122     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
123        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
124        for detecting groups that can match an empty string.
126     9. A pattern with a very large number of alternatives (more than several
127        hundred) was running out of internal workspace during the pre-compile
128        phase, where pcre_compile() figures out how much memory will be needed. A
129        bit of new cunning has reduced the workspace needed for groups with
130        alternatives. The 1000-alternative test pattern now uses 12 bytes of
131        workspace instead of running out of the 4096 that are available.
133    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
135    11. Applied patch from Google to remove an optimization that didn't quite work.
136        The report of the bug said:
138          pcrecpp::RE("a*").FullMatch("aaa") matches, while
139          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
140          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
142    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
143        it matched the wrong number of bytes.
146    Version 7.1 24-Apr-07
147    ---------------------
149     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
150        that is more "standard", making use of automake and other Autotools. There
151        is some re-arrangement of the files and adjustment of comments consequent
152        on this.
154     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
155        for recursive directory scanning broke on some systems because the files
156        are not scanned in any specific order and on different systems the order
157        was different. A call to "sort" has been inserted into RunGrepTest for the
158        approprate test as a short-term fix. In the longer term there may be an
159        alternative.
161     3. I had an email from Eric Raymond about problems translating some of PCRE's
162        man pages to HTML (despite the fact that I distribute HTML pages, some
163        people do their own conversions for various reasons). The problems
164        concerned the use of low-level troff macros .br and .in. I have therefore
165        removed all such uses from the man pages (some were redundant, some could
166        be replaced by .nf/.fi pairs). The 132html script that I use to generate
167        HTML has been updated to handle .nf/.fi and to complain if it encounters
168        .br or .in.
170     4. Updated comments in configure.ac that get placed in config.h.in and also
171        arranged for config.h to be included in the distribution, with the name
172        config.h.generic, for the benefit of those who have to compile without
173        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
175     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
176        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
177        makevp.bat for the current PCRE, using the additional files
178        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
180     6. A Windows user reported a minor discrepancy with test 2, which turned out
181        to be caused by a trailing space on an input line that had got lost in his
182        copy. The trailing space was an accident, so I've just removed it.
184     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
185        that is needed.
187     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
188        as "const" (a) because they are and (b) because it helps the PHP
189        maintainers who have recently made a script to detect big data structures
190        in the php code that should be moved to the .rodata section. I remembered
191        to update Builducptable as well, so it won't revert if ucptable.h is ever
192        re-created.
194     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
195        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
196        order to be able to cut out the UTF-8 tables in the latter when UTF-8
197        support is not required. This saves 1.5-2K of code, which is important in
198        some applications.
200        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
201        so as not to refer to the tables, even though these functions will never be
202        called when UTF-8 support is disabled. Otherwise there are problems with a
203        shared library.
205    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
207        (a) It was defining its arguments as char * instead of void *.
209        (b) It was assuming that all moves were upwards in memory; this was true
210            a long time ago when I wrote it, but is no longer the case.
212        The emulated memove() is provided for those environments that have neither
213        memmove() nor bcopy(). I didn't think anyone used it these days, but that
214        is clearly not the case, as these two bugs were recently reported.
216    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
217        and Detrail to create the HTML documentation, the .txt form of the man
218        pages, and it removes trailing spaces from listed files. It also creates
219        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
220        case, it wraps all the #defines with #ifndefs. This script should be run
221        before "make dist".
223    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
224        with Unicode property support.
226        (a) For a maximizing quantifier, if the two different cases of the
227            character were of different lengths in their UTF-8 codings (there are
228            some cases like this - I found 11), and the matching function had to
229            back up over a mixture of the two cases, it incorrectly assumed they
230            were both the same length.
232        (b) When PCRE was configured to use the heap rather than the stack for
233            recursion during matching, it was not correctly preserving the data for
234            the other case of a UTF-8 character when checking ahead for a match
235            while processing a minimizing repeat. If the check also involved
236            matching a wide character, but failed, corruption could cause an
237            erroneous result when trying to check for a repeat of the original
238            character.
240    13. Some tidying changes to the testing mechanism:
242        (a) The RunTest script now detects the internal link size and whether there
243            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
244            values substituted by "configure". (The RunGrepTest script already did
245            this for UTF-8.) The configure.ac script no longer substitutes the
246            relevant variables.
248        (b) The debugging options /B and /D in pcretest show the compiled bytecode
249            with length and offset values. This means that the output is different
250            for different internal link sizes. Test 2 is skipped for link sizes
251            other than 2 because of this, bypassing the problem. Unfortunately,
252            there was also a test in test 3 (the locale tests) that used /B and
253            failed for link sizes other than 2. Rather than cut the whole test out,
254            I have added a new /Z option to pcretest that replaces the length and
255            offset values with spaces. This is now used to make test 3 independent
256            of link size. (Test 2 will be tidied up later.)
258    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
259        segmentation fault instead of returning the appropriate error message.
261    15. In multiline mode when the newline sequence was set to "any", the pattern
262        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
263        This doesn't seem right; it now treats the CRLF combination as the line
264        ending, and so does not match in that case. It's only a pattern such as ^$
265        that would hit this one: something like ^ABC$ would have failed after \r
266        and then tried again after \r\n.
268    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
269        in an attempt to make files that differ only in their line terminators
270        compare equal. This works on Linux.
272    17. Under certain error circumstances pcregrep might try to free random memory
273        as it exited. This is now fixed, thanks to valgrind.
275    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
276        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
277        was because its rules for how to advance for /g after matching an empty
278        string at the end of a line did not allow for this case. They now check for
279        it specially.
281    20. pcretest is supposed to handle patterns and data of any length, by
282        extending its buffers when necessary. It was getting this wrong when the
283        buffer for a data line had to be extended.
285    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
286        CRLF as a newline sequence.
288    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
289        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
290        I have nevertheless tidied it up.
292    23. Added some casts to kill warnings from HP-UX ia64 compiler.
294    24. Added a man page for pcre-config.
297    Version 7.0 19-Dec-06
298    ---------------------
300     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
301        moving to gcc 4.1.1.
303     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
304        sys/time.h, which is documented as needed for this function. It doesn't
305        seem to matter on Linux, but it showed up on some releases of OS X.
307     3. It seems that there are systems where bytes whose values are greater than
308        127 match isprint() in the "C" locale. The "C" locale should be the
309        default when a C program starts up. In most systems, only ASCII printing
310        characters match isprint(). This difference caused the output from pcretest
311        to vary, making some of the tests fail. I have changed pcretest so that:
313        (a) When it is outputting text in the compiled version of a pattern, bytes
314            other than 32-126 are always shown as hex escapes.
316        (b) When it is outputting text that is a matched part of a subject string,
317            it does the same, unless a different locale has been set for the match
318            (using the /L modifier). In this case, it uses isprint() to decide.
320     4. Fixed a major bug that caused incorrect computation of the amount of memory
321        required for a compiled pattern when options that changed within the
322        pattern affected the logic of the preliminary scan that determines the
323        length. The relevant options are -x, and -i in UTF-8 mode. The result was
324        that the computed length was too small. The symptoms of this bug were
325        either the PCRE error "internal error: code overflow" from pcre_compile(),
326        or a glibc crash with a message such as "pcretest: free(): invalid next
327        size (fast)". Examples of patterns that provoked this bug (shown in
328        pcretest format) are:
330          /(?-x: )/x
331          /(?x)(?-x: \s*#\s*)/
332          /((?i)[\x{c0}])/8
333          /(?i:[\x{c0}])/8
335        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
336        is now done differently.
338     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
339        wrapper classes; (b) implement a new function in the C++ scanner that is
340        more efficient than the old way of doing things because it avoids levels of
341        recursion in the regex matching; (c) add a paragraph to the documentation
342        for the FullMatch() function.
344     6. The escape sequence \n was being treated as whatever was defined as
345        "newline". Not only was this contrary to the documentation, which states
346        that \n is character 10 (hex 0A), but it also went horribly wrong when
347        "newline" was defined as CRLF. This has been fixed.
349     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
350        was being set to -1 for the "end of line" case (supposedly a value that no
351        character can have). Though this value is never used (the check for end of
352        line is "zero bytes in current character"), it caused compiler complaints.
353        I've changed it to 0xffffffff.
355     8. In pcre_version.c, the version string was being built by a sequence of
356        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
357        string (as it is for production releases) called a macro with an empty
358        argument. The C standard says the result of this is undefined. The gcc
359        compiler treats it as an empty string (which was what was wanted) but it is
360        reported that Visual C gives an error. The source has been hacked around to
361        avoid this problem.
363     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
364        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
365        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
366        of them did).
368    10. Originally, pcretest opened its input and output without "b"; then I was
369        told that "b" was needed in some environments, so it was added for release
370        5.0 to both the input and output. (It makes no difference on Unix-like
371        systems.) Later I was told that it is wrong for the input on Windows. I've
372        now abstracted the modes into two macros, to make it easier to fiddle with
373        them, and removed "b" from the input mode under Windows.
375    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
377    12. Added -help and --help to pcretest as an official way of being reminded
378        of the options.
380    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
381        and pcrecpp.cc because they annoy compilers at high warning levels.
383    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
385    15. Fixed an occurrence of == in configure.ac that should have been = (shell
386        scripts are not C programs :-) and which was not noticed because it works
387        on Linux.
389    16. pcretest is supposed to handle any length of pattern and data line (as one
390        line or as a continued sequence of lines) by extending its input buffer if
391        necessary. This feature was broken for very long pattern lines, leading to
392        a string of junk being passed to pcre_compile() if the pattern was longer
393        than about 50K.
395    17. I have done a major re-factoring of the way pcre_compile() computes the
396        amount of memory needed for a compiled pattern. Previously, there was code
397        that made a preliminary scan of the pattern in order to do this. That was
398        OK when PCRE was new, but as the facilities have expanded, it has become
399        harder and harder to keep it in step with the real compile phase, and there
400        have been a number of bugs (see for example, 4 above). I have now found a
401        cunning way of running the real compile function in a "fake" mode that
402        enables it to compute how much memory it would need, while actually only
403        ever using a few hundred bytes of working memory and without too many
404        tests of the mode. This should make future maintenance and development
405        easier. A side effect of this work is that the limit of 200 on the nesting
406        depth of parentheses has been removed (though this was never a serious
407        limitation, I suspect). However, there is a downside: pcre_compile() now
408        runs more slowly than before (30% or more, depending on the pattern). I
409        hope this isn't a big issue. There is no effect on runtime performance.
411    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
412        newline (only possible for the last line of a file) and it was a
413        pattern that set a locale (followed by /Lsomething), pcretest crashed.
415    19. Added additional timing features to pcretest. (1) The -tm option now times
416        matching only, not compiling. (2) Both -t and -tm can be followed, as a
417        separate command line item, by a number that specifies the number of
418        repeats to use when timing. The default is 50000; this gives better
419        precision, but takes uncomfortably long for very large patterns.
421    20. Extended pcre_study() to be more clever in cases where a branch of a
422        subpattern has no definite first character. For example, (a*|b*)[cd] would
423        previously give no result from pcre_study(). Now it recognizes that the
424        first character must be a, b, c, or d.
426    21. There was an incorrect error "recursive call could loop indefinitely" if
427        a subpattern (or the entire pattern) that was being tested for matching an
428        empty string contained only one non-empty item after a nested subpattern.
429        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
430        incorrectly, because the \d was being skipped in the check.
432    22. The pcretest program now has a new pattern option /B and a command line
433        option -b, which is equivalent to adding /B to every pattern. This causes
434        it to show the compiled bytecode, without the additional information that
435        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
436        is the same as /B/I).
438    23. A new optimization is now able automatically to treat some sequences such
439        as a*b as a*+b. More specifically, if something simple (such as a character
440        or a simple class like \d) has an unlimited quantifier, and is followed by
441        something that cannot possibly match the quantified thing, the quantifier
442        is automatically "possessified".
444    24. A recursive reference to a subpattern whose number was greater than 39
445        went wrong under certain circumstances in UTF-8 mode. This bug could also
446        have affected the operation of pcre_study().
448    25. Realized that a little bit of performance could be had by replacing
449        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
451    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
453    27. Possessive quantifiers such as a++ were previously implemented by turning
454        them into atomic groups such as ($>a+). Now they have their own opcodes,
455        which improves performance. This includes the automatically created ones
456        from 23 above.
458    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
459        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
460        the first matched character to be a colon. This applied both to named and
461        numbered groups.
463    29. The ucpinternal.h header file was missing its idempotency #ifdef.
465    30. I was sent a "project" file called libpcre.a.dev which I understand makes
466        building PCRE on Windows easier, so I have included it in the distribution.
468    31. There is now a check in pcretest against a ridiculously large number being
469        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
470        loop, the loop is abandoned.
472    32. Forward references to subpatterns in conditions such as (?(2)...) where
473        subpattern 2 is defined later cause pcre_compile() to search forwards in
474        the pattern for the relevant set of parentheses. This search went wrong
475        when there were unescaped parentheses in a character class, parentheses
476        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
478    33. "Subroutine" calls and backreferences were previously restricted to
479        referencing subpatterns earlier in the regex. This restriction has now
480        been removed.
482    34. Added a number of extra features that are going to be in Perl 5.10. On the
483        whole, these are just syntactic alternatives for features that PCRE had
484        previously implemented using the Python syntax or my own invention. The
485        other formats are all retained for compatibility.
487        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
488            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
489            also .NET compatible.
491        (b) A recursion or subroutine call to a named group can now be defined as
492            (?&name) as well as (?P>name).
494        (c) A backreference to a named group can now be defined as \k<name> or
495            \k'name' as well as (?P=name). The new forms, as well as being in Perl
496            5.10, are also .NET compatible.
498        (d) A conditional reference to a named group can now use the syntax
499            (?(<name>) or (?('name') as well as (?(name).
501        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
502            groups (named and numbered) that are never evaluated inline, but can be
503            called as "subroutines" from elsewhere. In effect, the DEFINE condition
504            is always false. There may be only one alternative in such a group.
506        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
507            as the simple (?(R). The condition is true only if the most recent
508            recursion is that of the given number or name. It does not search out
509            through the entire recursion stack.
511        (g) The escape \gN or \g{N} has been added, where N is a positive or
512            negative number, specifying an absolute or relative reference.
514    35. Tidied to get rid of some further signed/unsigned compiler warnings and
515        some "unreachable code" warnings.
517    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
518        things, this adds five new scripts.
520    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
521        There were also incompatibilities regarding the handling of \Q..\E inside
522        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
523        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
525    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
526        matches an empty string, and forcibly breaks the loop. There were bugs in
527        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
528        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
529        separate and independent bugs (that affected different cases) have been
530        fixed.
532    39. Refactored the code to abolish the use of different opcodes for small
533        capturing bracket numbers. This is a tidy that I avoided doing when I
534        removed the limit on the number of capturing brackets for 3.5 back in 2001.
535        The new approach is not only tidier, it makes it possible to reduce the
536        memory needed to fix the previous bug (38).
538    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
539        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
540        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
541        mode.
543    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
544        report.
546    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
547        copy construction and assignment in the C++ wrapper.
549    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
550        couple of bugs that could have given wrong results in the "--newline=crlf"
551        case.
553    44. Added a number of casts and did some reorganization of signed/unsigned int
554        variables following suggestions from Dair Grant. Also renamed the variable
555        "this" as "item" because it is a C++ keyword.
557    45. Arranged for dftables to add
559          #include "pcre_internal.h"
561        to pcre_chartables.c because without it, gcc 4.x may remove the array
562        definition from the final binary if PCRE is built into a static library and
563        dead code stripping is activated.
565    46. For an unanchored pattern, if a match attempt fails at the start of a
566        newline sequence, and the newline setting is CRLF or ANY, and the next two
567        characters are CRLF, advance by two characters instead of one.
570    Version 6.7 04-Jul-06
571    ---------------------
573     1. In order to handle tests when input lines are enormously long, pcretest has
574        been re-factored so that it automatically extends its buffers when
575        necessary. The code is crude, but this _is_ just a test program. The
576        default size has been increased from 32K to 50K.
578     2. The code in pcre_study() was using the value of the re argument before
579        testing it for NULL. (Of course, in any sensible call of the function, it
580        won't be NULL.)
582     3. The memmove() emulation function in pcre_internal.h, which is used on
583        systems that lack both memmove() and bcopy() - that is, hardly ever -
584        was missing a "static" storage class specifier.
586     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
587        containing an extended class (one that cannot be represented by a bitmap
588        because it contains high-valued characters or Unicode property items, e.g.
589        [\pZ]). Almost always one would set UTF-8 mode when processing such a
590        pattern, but PCRE should not loop if you do not (it no longer does).
591        [Detail: two cases were found: (a) a repeated subpattern containing an
592        extended class; (b) a recursive reference to a subpattern that followed a
593        previous extended class. It wasn't skipping over the extended class
594        correctly when UTF-8 mode was not set.]
596     5. A negated single-character class was not being recognized as fixed-length
597        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
598        compile error "lookbehind assertion is not fixed length".
600     6. The RunPerlTest auxiliary script was showing an unexpected difference
601        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
602        write a Perl script that can interpret lines of an input file either as
603        byte characters or as UTF-8, which is what "perltest" was being required to
604        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
605        can't do is switch easily at run time between having the "use utf8;" pragma
606        or not. In the end, I fudged it by using the RunPerlTest script to insert
607        "use utf8;" explicitly for the UTF-8 tests.
609     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
610        the end of the subject string, contrary to the documentation and to what
611        Perl does. This was true of both matching functions. Now it matches only at
612        the start of the subject and immediately after *internal* newlines.
614     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
615        a pointer to an int instead of a pointer to an unsigned long int. This
616        caused problems on 64-bit systems.
618     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
619        instance of the 'standard' template library not being so standard".
621    10. There was no check on the number of named subpatterns nor the maximum
622        length of a subpattern name. The product of these values is used to compute
623        the size of the memory block for a compiled pattern. By supplying a very
624        long subpattern name and a large number of named subpatterns, the size
625        computation could be caused to overflow. This is now prevented by limiting
626        the length of names to 32 characters, and the number of named subpatterns
627        to 10,000.
629    11. Subpatterns that are repeated with specific counts have to be replicated in
630        the compiled pattern. The size of memory for this was computed from the
631        length of the subpattern and the repeat count. The latter is limited to
632        65535, but there was no limit on the former, meaning that integer overflow
633        could in principle occur. The compiled length of a repeated subpattern is
634        now limited to 30,000 bytes in order to prevent this.
636    12. Added the optional facility to have named substrings with the same name.
638    13. Added the ability to use a named substring as a condition, using the
639        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
640        are numbers (not recommended). Forward references are permitted.
642    14. Added forward references in named backreferences (if you see what I mean).
644    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
645        pattern could run off the end of the subject. For example, the pattern
646        "(?s)(.{1,5})"8 did this with the subject "ab".
648    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
649        PCRE_CASELESS was set when matching characters that were quantified with ?
650        or *.
652    17. A character class other than a single negated character that had a minimum
653        but no maximum quantifier - for example [ab]{6,} - was not handled
654        correctly by pce_dfa_exec(). It would match only one character.
656    18. A valid (though odd) pattern that looked like a POSIX character
657        class but used an invalid character after [ (for example [[,abc,]]) caused
658        pcre_compile() to give the error "Failed: internal error: code overflow" or
659        in some cases to crash with a glibc free() error. This could even happen if
660        the pattern terminated after [[ but there just happened to be a sequence of
661        letters, a binary zero, and a closing ] in the memory that followed.
663    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
664        over the years. Originally (before any Unicode support), just the bottom 8
665        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
666        output from "man perlunicode" includes this:
668          The regular expression compiler produces polymorphic opcodes.  That
669          is, the pattern adapts to the data and automatically switches to
670          the Unicode character scheme when presented with Unicode data--or
671          instead uses a traditional byte scheme when presented with byte
672          data.
674        Sadly, a wide octal escape does not cause a switch, and in a string with
675        no other multibyte characters, these octal escapes are treated as before.
676        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
677        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
678        Unicode string.
680        I have not perpetrated such confusion in PCRE. Up till now, it took just
681        the bottom 8 bits, as in old Perl. I have now made octal escapes with
682        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
683        translate to the appropriate multibyte character.
685    29. Applied some refactoring to reduce the number of warnings from Microsoft
686        and Borland compilers. This has included removing the fudge introduced
687        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
688        a warning about an unused variable.
690    21. PCRE has not included VT (character 0x0b) in the set of whitespace
691        characters since release 4.0, because Perl (from release 5.004) does not.
692        [Or at least, is documented not to: some releases seem to be in conflict
693        with the documentation.] However, when a pattern was studied with
694        pcre_study() and all its branches started with \s, PCRE still included VT
695        as a possible starting character. Of course, this did no harm; it just
696        caused an unnecessary match attempt.
698    22. Removed a now-redundant internal flag bit that recorded the fact that case
699        dependency changed within the pattern. This was once needed for "required
700        byte" processing, but is no longer used. This recovers a now-scarce options
701        bit. Also moved the least significant internal flag bit to the most-
702        significant bit of the word, which was not previously used (hangover from
703        the days when it was an int rather than a uint) to free up another bit for
704        the future.
706    23. Added support for CRLF line endings as well as CR and LF. As well as the
707        default being selectable at build time, it can now be changed at runtime
708        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
709        specify that it is scanning data with non-default line endings.
711    24. Changed the definition of CXXLINK to make it agree with the definition of
712        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
714    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
715        recursions. This makes a big different to stack usage for some patterns.
717    26. If a subpattern containing a named recursion or subroutine reference such
718        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
719        the space required for the compiled pattern went wrong and gave too small a
720        value. Depending on the environment, this could lead to "Failed: internal
721        error: code overflow at offset 49" or "glibc detected double free or
722        corruption" errors.
724    27. Applied patches from Google (a) to support the new newline modes and (b) to
725        advance over multibyte UTF-8 characters in GlobalReplace.
727    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
728        difference for some implementation of PCRE in some Windows version.
730    29. Added some extra testing facilities to pcretest:
732        \q<number>   in a data line sets the "match limit" value
733        \Q<number>   in a data line sets the "match recursion limt" value
734        -S <number>  sets the stack size, where <number> is in megabytes
736        The -S option isn't available for Windows.
739    Version 6.6 06-Feb-06
740    ---------------------
742     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
743        in pcreposix.h. I have copied the definition from pcre.h.
745     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
746        because pcre.h is no longer a built file.
748     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
749        not normally included in the compiled code.
752    Version 6.5 01-Feb-06
753    ---------------------
755     1. When using the partial match feature with pcre_dfa_exec(), it was not
756        anchoring the second and subsequent partial matches at the new starting
757        point. This could lead to incorrect results. For example, with the pattern
758        /1234/, partially matching against "123" and then "a4" gave a match.
760     2. Changes to pcregrep:
762        (a) All non-match returns from pcre_exec() were being treated as failures
763            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
764            error message is output. Some extra information is given for the
765            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
766            probably the only errors that are likely to be caused by users (by
767            specifying a regex that has nested indefinite repeats, for instance).
768            If there are more than 20 of these errors, pcregrep is abandoned.
770        (b) A binary zero was treated as data while matching, but terminated the
771            output line if it was written out. This has been fixed: binary zeroes
772            are now no different to any other data bytes.
774        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
775            used to set a locale for matching. The --locale=xxxx long option has
776            been added (no short equivalent) to specify a locale explicitly on the
777            pcregrep command, overriding the environment variables.
779        (d) When -B was used with -n, some line numbers in the output were one less
780            than they should have been.
782        (e) Added the -o (--only-matching) option.
784        (f) If -A or -C was used with -c (count only), some lines of context were
785            accidentally printed for the final match.
787        (g) Added the -H (--with-filename) option.
789        (h) The combination of options -rh failed to suppress file names for files
790            that were found from directory arguments.
792        (i) Added the -D (--devices) and -d (--directories) options.
794        (j) Added the -F (--fixed-strings) option.
796        (k) Allow "-" to be used as a file name for -f as well as for a data file.
798        (l) Added the --colo(u)r option.
800        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
801            is not present by default.
803     3. A nasty bug was discovered in the handling of recursive patterns, that is,
804        items such as (?R) or (?1), when the recursion could match a number of
805        alternatives. If it matched one of the alternatives, but subsequently,
806        outside the recursion, there was a failure, the code tried to back up into
807        the recursion. However, because of the way PCRE is implemented, this is not
808        possible, and the result was an incorrect result from the match.
810        In order to prevent this happening, the specification of recursion has
811        been changed so that all such subpatterns are automatically treated as
812        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
814     4. I had overlooked the fact that, in some locales, there are characters for
815        which isalpha() is true but neither isupper() nor islower() are true. In
816        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
817        and ordfeminine) are like this. This affected the treatment of \w and \W
818        when they appeared in character classes, but not when they appeared outside
819        a character class. The bit map for "word" characters is now created
820        separately from the results of isalnum() instead of just taking it from the
821        upper, lower, and digit maps. (Plus the underscore character, of course.)
823     5. The above bug also affected the handling of POSIX character classes such as
824        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
825        permanent tables. Instead, the bit maps for such a class were previously
826        created as the appropriate unions of the upper, lower, and digit bitmaps.
827        Now they are created by subtraction from the [[:word:]] class, which has
828        its own bitmap.
830     6. The [[:blank:]] character class matches horizontal, but not vertical space.
831        It is created by subtracting the vertical space characters (\x09, \x0a,
832        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
833        subtraction was done in the overall bitmap for a character class, meaning
834        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
835        be recognized. This bug has been fixed.
837     7. Patches from the folks at Google:
839          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
840          real life, but is still worth protecting against".
842          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
843          regular expressions".
845          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
846          have it.
848          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
849          "configure" and the latter not, in order to fix a problem somebody had
850          with compiling the Arg class on HP-UX.
852          (e) Improve the error-handling of the C++ wrapper a little bit.
854          (f) New tests for checking recursion limiting.
856     8. The pcre_memmove() function, which is used only if the environment does not
857        have a standard memmove() function (and is therefore rarely compiled),
858        contained two bugs: (a) use of int instead of size_t, and (b) it was not
859        returning a result (though PCRE never actually uses the result).
861     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
862        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
863        returned instead of calling malloc() with an overflowing number that would
864        most likely cause subsequent chaos.
866    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
868    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
869        with this option is matched, the nmatch and pmatch options of regexec() are
870        ignored.
872    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
873        provided in case anyone wants to the the POSIX interface with UTF-8
874        strings.
876    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
877        C++ linking (needed for some HP-UX environments).
879    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
880        (unused parameter) and in the pcre_printint() function (omitted "default"
881        switch label when the default is to do nothing).
883    15. Added some code to make it possible, when PCRE is compiled as a C++
884        library, to replace subject pointers for pcre_exec() with a smart pointer
885        class, thus making it possible to process discontinuous strings.
887    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
888        much the same function. They were added by different people who were trying
889        to make PCRE easy to compile on non-Unix systems. It has been suggested
890        that PCRE_EXPORT be abolished now that there is more automatic apparatus
891        for compiling on Windows systems. I have therefore replaced it with
892        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
893        defaults to "extern" for C or "extern C" for C++, which works fine on
894        Unix-like systems. It is now possible to override the value of PCRE_DATA_
895        SCOPE with something explicit in config.h. In addition:
897        (a) pcreposix.h still had just "extern" instead of either of these macros;
898            I have replaced it with PCRE_DATA_SCOPE.
900        (b) Functions such as _pcre_xclass(), which are internal to the library,
901            but external in the C sense, all had PCRE_EXPORT in their definitions.
902            This is apparently wrong for the Windows case, so I have removed it.
903            (It makes no difference on Unix-like systems.)
905    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
906        of recursive calls to match(). This is different to MATCH_LIMIT because
907        that limits the total number of calls to match(), not all of which increase
908        the depth of recursion. Limiting the recursion depth limits the amount of
909        stack (or heap if NO_RECURSE is set) that is used. The default can be set
910        when PCRE is compiled, and changed at run time. A patch from Google adds
911        this functionality to the C++ interface.
913    18. Changes to the handling of Unicode character properties:
915        (a) Updated the table to Unicode 4.1.0.
917        (b) Recognize characters that are not in the table as "Cn" (undefined).
919        (c) I revised the way the table is implemented to a much improved format
920            which includes recognition of ranges. It now supports the ranges that
921            are defined in UnicodeData.txt, and it also amalgamates other
922            characters into ranges. This has reduced the number of entries in the
923            table from around 16,000 to around 3,000, thus reducing its size
924            considerably. I realized I did not need to use a tree structure after
925            all - a binary chop search is just as efficient. Having reduced the
926            number of entries, I extended their size from 6 bytes to 8 bytes to
927            allow for more data.
929        (d) Added support for Unicode script names via properties such as \p{Han}.
931    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
932        matching that character.
934    20. When matching a repeated Unicode property with a minimum greater than zero,
935        (for example \pL{2,}), PCRE could look past the end of the subject if it
936        reached it while seeking the minimum number of characters. This could
937        happen only if some of the characters were more than one byte long, because
938        there is a check for at least the minimum number of bytes.
940    21. Refactored the implementation of \p and \P so as to be more general, to
941        allow for more different types of property in future. This has changed the
942        compiled form incompatibly. Anybody with saved compiled patterns that use
943        \p or \P will have to recompile them.
945    22. Added "Any" and "L&" to the supported property types.
947    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
948        but give a compile time error if the value is greater than 0xff.
950    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
951        accidentally not being installed or uninstalled.
953    25. The pcre.h file was built from pcre.h.in, but the only changes that were
954        made were to insert the current release number. This seemed silly, because
955        it made things harder for people building PCRE on systems that don't run
956        "configure". I have turned pcre.h into a distributed file, no longer built
957        by "configure", with the version identification directly included. There is
958        no longer a pcre.h.in file.
960        However, this change necessitated a change to the pcre-config script as
961        well. It is built from pcre-config.in, and one of the substitutions was the
962        release number. I have updated configure.ac so that ./configure now finds
963        the release number by grepping pcre.h.
965    26. Added the ability to run the tests under valgrind.
968    Version 6.4 05-Sep-05
969    ---------------------
971     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
972        "--" to be printed when multiple files were scanned, even when none of the
973        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
974        consider it to be a bug, and have restored the previous behaviour.
976     2. A couple of code tidies to get rid of compiler warnings.
978     3. The pcretest program used to cheat by referring to symbols in the library
979        whose names begin with _pcre_. These are internal symbols that are not
980        really supposed to be visible externally, and in some environments it is
981        possible to suppress them. The cheating is now confined to including
982        certain files from the library's source, which is a bit cleaner.
984     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
985        file's purpose clearer.
987     5. Reorganized pcre_ucp_findchar().
990    Version 6.3 15-Aug-05
991    ---------------------
993     1. The file libpcre.pc.in did not have general read permission in the tarball.
995     2. There were some problems when building without C++ support:
997        (a) If C++ support was not built, "make install" and "make test" still
998            tried to test it.
1000        (b) There were problems when the value of CXX was explicitly set. Some
1001            changes have been made to try to fix these, and ...
1003        (c) --disable-cpp can now be used to explicitly disable C++ support.
1005        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1006            backslash in a target when C++ was disabled. This confuses some
1007            versions of "make", apparently. Using an intermediate variable solves
1008            this. (Same for CPP_LOBJ.)
1010     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1011        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1012        necessary on certain architectures.
1014     4. Added a setting of -export-symbols-regex to the link command to remove
1015        those symbols that are exported in the C sense, but actually are local
1016        within the library, and not documented. Their names all begin with
1017        "_pcre_". This is not a perfect job, because (a) we have to except some
1018        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1019        available (and never for static libraries). I have made a note to try to
1020        find a way round (a) in the future.
1023    Version 6.2 01-Aug-05
1024    ---------------------
1026     1. There was no test for integer overflow of quantifier values. A construction
1027        such as {1111111111111111} would give undefined results. What is worse, if
1028        a minimum quantifier for a parenthesized subpattern overflowed and became
1029        negative, the calculation of the memory size went wrong. This could have
1030        led to memory overwriting.
1032     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1034     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1035        operating environments where this matters.
1037     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1038        PCRE options from within the C++ wrapper.
1040     5. Named capturing subpatterns were not being correctly counted when a pattern
1041        was compiled. This caused two problems: (a) If there were more than 100
1042        such subpatterns, the calculation of the memory needed for the whole
1043        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1044        back references of the form \12, where the number was greater than 9, were
1045        not recognized as back references, even though there were sufficient
1046        previous subpatterns.
1048     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1049        versions of gcc, e.g. 2.95.4.
1052    Version 6.1 21-Jun-05
1053    ---------------------
1055     1. There was one reference to the variable "posix" in pcretest.c that was not
1056        surrounded by "#if !defined NOPOSIX".
1058     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1059        the cross-check on the old pcre_info() function, for the benefit of the
1060        cut-down version of PCRE that is currently imported into Exim.
1062     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1063        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1064        patterns that start (?i) but I don't think that matters. The use of (?i) is
1065        just an example; this all applies to the other options as well.
1067     4. Since libtool seems to echo the compile commands it is issuing, the output
1068        from "make" can be reduced a bit by putting "@" in front of each libtool
1069        compile command.
1071     5. Patch from the folks at Google for configure.in to be a bit more thorough
1072        in checking for a suitable C++ installation before trying to compile the
1073        C++ stuff. This should fix a reported problem when a compiler was present,
1074        but no suitable headers.
1076     6. The man pages all had just "PCRE" as their title. I have changed them to
1077        be the relevant file name. I have also arranged that these names are
1078        retained in the file doc/pcre.txt, which is a concatenation in text format
1079        of all the man pages except the little individual ones for each function.
1081     7. The NON-UNIX-USE file had not been updated for the different set of source
1082        files that come with release 6. I also added a few comments about the C++
1083        wrapper.
1086    Version 6.0 07-Jun-05
1087    ---------------------
1089     1. Some minor internal re-organization to help with my DFA experiments.
1091     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1092        didn't matter for the library itself when fully configured, but did matter
1093        when compiling without UCP support, or within Exim, where the ucp files are
1094        not imported.
1096     3. Refactoring of the library code to split up the various functions into
1097        different source modules. The addition of the new DFA matching code (see
1098        below) to a single monolithic source would have made it really too
1099        unwieldy, quite apart from causing all the code to be include in a
1100        statically linked application, when only some functions are used. This is
1101        relevant even without the DFA addition now that patterns can be compiled in
1102        one application and matched in another.
1104        The downside of splitting up is that there have to be some external
1105        functions and data tables that are used internally in different modules of
1106        the library but which are not part of the API. These have all had their
1107        names changed to start with "_pcre_" so that they are unlikely to clash
1108        with other external names.
1110     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1111        a different (DFA) algorithm. Although it is slower than the original
1112        function, it does have some advantages for certain types of matching
1113        problem.
1115     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1116        including restarting after a partial match.
1118     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1119        defined when compiling for Windows was sent to me. I have put it into the
1120        code, though I have no means of testing or verifying it.
1122     7. Added the pcre_refcount() auxiliary function.
1124     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1125        match before or at the first newline in the subject string. In pcretest,
1126        the /f option on a pattern can be used to set this.
1128     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1129        would behave wrongly. This has been present in PCRE since release 4.0.
1131    10. A number of changes to the pcregrep command:
1133        (a) Refactored how -x works; insert ^(...)$ instead of setting
1134            PCRE_ANCHORED and checking the length, in preparation for adding
1135            something similar for -w.
1137        (b) Added the -w (match as a word) option.
1139        (c) Refactored the way lines are read and buffered so as to have more
1140            than one at a time available.
1142        (d) Implemented a pcregrep test script.
1144        (e) Added the -M (multiline match) option. This allows patterns to match
1145            over several lines of the subject. The buffering ensures that at least
1146            8K, or the rest of the document (whichever is the shorter) is available
1147            for matching (and similarly the previous 8K for lookbehind assertions).
1149        (f) Changed the --help output so that it now says
1151              -w, --word-regex(p)
1153            instead of two lines, one with "regex" and the other with "regexp"
1154            because that confused at least one person since the short forms are the
1155            same. (This required a bit of code, as the output is generated
1156            automatically from a table. It wasn't just a text change.)
1158        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1159            option but starts with a hyphen. Could be a pattern or a path name
1160            starting with a hyphen, for instance.
1162        (h) "-" can be given as a file name to represent stdin.
1164        (i) When file names are being printed, "(standard input)" is used for
1165            the standard input, for compatibility with GNU grep. Previously
1166            "<stdin>" was used.
1168        (j) The option --label=xxx can be used to supply a name to be used for
1169            stdin when file names are being printed. There is no short form.
1171        (k) Re-factored the options decoding logic because we are going to add
1172            two more options that take data. Such options can now be given in four
1173            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1175        (l) Added the -A, -B, and -C options for requesting that lines of context
1176            around matches be printed.
1178        (m) Added the -L option to print the names of files that do not contain
1179            any matching lines, that is, the complement of -l.
1181        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1182            continue to scan other files.
1184        (o) The -s option was incorrectly implemented. For compatibility with other
1185            greps, it now suppresses the error message for a non-existent or non-
1186            accessible file (but not the return code). There is a new option called
1187            -q that suppresses the output of matching lines, which was what -s was
1188            previously doing.
1190        (p) Added --include and --exclude options to specify files for inclusion
1191            and exclusion when recursing.
1193    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1194        Hopefully, it now does.
1196    12. Missing cast in pcre_study().
1198    13. Added an "uninstall" target to the makefile.
1200    14. Replaced "extern" in the function prototypes in Makefile.in with
1201        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1202        world, but is set differently for Windows.
1204    15. Added a second compiling function called pcre_compile2(). The only
1205        difference is that it has an extra argument, which is a pointer to an
1206        integer error code. When there is a compile-time failure, this is set
1207        non-zero, in addition to the error test pointer being set to point to an
1208        error message. The new argument may be NULL if no error number is required
1209        (but then you may as well call pcre_compile(), which is now just a
1210        wrapper). This facility is provided because some applications need a
1211        numeric error indication, but it has also enabled me to tidy up the way
1212        compile-time errors are handled in the POSIX wrapper.
1214    16. Added VPATH=.libs to the makefile; this should help when building with one
1215        prefix path and installing with another. (Or so I'm told by someone who
1216        knows more about this stuff than I do.)
1218    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1219        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1220        match everything, including newlines. This is not POSIX-compatible, but
1221        somebody wanted the feature. From pcretest it can be activated by using
1222        both the P and the s flags.
1224    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1226    19. libpcre.pc was being incorrectly installed as executable.
1228    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1229        it now also looks for '\r' so that it will work unmodified on Windows.
1231    21. Added Google's contributed C++ wrapper to the distribution.
1233    22. Added some untidy missing memory free() calls in pcretest, to keep
1234        Electric Fence happy when testing.
1238    Version 5.0 13-Sep-04
1239    ---------------------
1241     1. Internal change: literal characters are no longer packed up into items
1242        containing multiple characters in a single byte-string. Each character
1243        is now matched using a separate opcode. However, there may be more than one
1244        byte in the character in UTF-8 mode.
1246     2. The pcre_callout_block structure has two new fields: pattern_position and
1247        next_item_length. These contain the offset in the pattern to the next match
1248        item, and its length, respectively.
1250     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1251        insertion of callouts before each pattern item. Added the /C option to
1252        pcretest to make use of this.
1254     4. On the advice of a Windows user, the lines
1256          #if defined(_WIN32) || defined(WIN32)
1257          _setmode( _fileno( stdout ), 0x8000 );
1258          #endif  /* defined(_WIN32) || defined(WIN32) */
1260        have been added to the source of pcretest. This apparently does useful
1261        magic in relation to line terminators.
1263     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1264        for the benefit of those environments where the "b" makes a difference.
1266     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1267        to know about it. I have put a hack into configure.in that adds in code
1268        to set GCC=yes if CC=icc. This seems to end up at a point in the
1269        generated configure script that is early enough to affect the setting of
1270        compiler options, which is what is needed, but I have no means of testing
1271        whether it really works. (The user who reported this had patched the
1272        generated configure script, which of course I cannot do.)
1274        LATER: After change 22 below (new libtool files), the configure script
1275        seems to know about icc (and also ecc). Therefore, I have commented out
1276        this hack in configure.in.
1278     7. Added support for pkg-config (2 patches were sent in).
1280     8. Negated POSIX character classes that used a combination of internal tables
1281        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1282        [[:^ascii]]. Typically, they would match almost any characters. The other
1283        POSIX classes were not broken in this way.
1285     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1286        to find the match, as PCRE was deluded into thinking that the match had to
1287        start at the start point or following a newline. The same bug applied to
1288        patterns with negative forward assertions or any backward assertions
1289        preceding ".*" at the start, unless the pattern required a fixed first
1290        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1292    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1293        starting at the last subject character, bytes beyond the end of the subject
1294        string were read.
1296    11. Renamed the variable "class" as "classbits" to make life easier for C++
1297        users. (Previously there was a macro definition, but it apparently wasn't
1298        enough.)
1300    12. Added the new field "tables" to the extra data so that tables can be passed
1301        in at exec time, or the internal tables can be re-selected. This allows
1302        a compiled regex to be saved and re-used at a later time by a different
1303        program that might have everything at different addresses.
1305    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1306        -R library as well as a -L library.
1308    14. The debugging options of pcretest (-d on the command line or D on a
1309        pattern) showed incorrect output for anything following an extended class
1310        that contained multibyte characters and which was followed by a quantifier.
1312    15. Added optional support for general category Unicode character properties
1313        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1314        support. It adds about 90K to the size of the library. The meanings of the
1315        inbuilt class escapes such as \d and \s have NOT been changed.
1317    16. Updated pcredemo.c to include calls to free() to release the memory for the
1318        compiled pattern.
1320    17. The generated file chartables.c was being created in the source directory
1321        instead of in the building directory. This caused the build to fail if the
1322        source directory was different from the building directory, and was
1323        read-only.
1325    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1326        file. No doubt somebody will tell me if they don't make sense... Also added
1327        Dan Mooney's comments about building on OpenVMS.
1329    19. Added support for partial matching via the PCRE_PARTIAL option for
1330        pcre_exec() and the \P data escape in pcretest.
1332    20. Extended pcretest with 3 new pattern features:
1334        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1335              write the compiled pattern to the file whose name is "rest-of-line".
1336              This is a straight binary dump of the data, with the saved pointer to
1337              the character tables forced to be NULL. The study data, if any, is
1338              written too. After writing, pcretest reads a new pattern.
1340        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1341              compiled pattern from the given file. There must not be any
1342              occurrences of "<" in the file name (pretty unlikely); if there are,
1343              pcretest will instead treat the initial "<" as a pattern delimiter.
1344              After reading in the pattern, pcretest goes on to read data lines as
1345              usual.
1347        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1348              and 16-bit fields in a compiled pattern, to simulate a pattern that
1349              was compiled on a host of opposite endianness.
1351    21. The pcre-exec() function can now cope with patterns that were compiled on
1352        hosts of opposite endianness, with this restriction:
1354          As for any compiled expression that is saved and used later, the tables
1355          pointer field cannot be preserved; the extra_data field in the arguments
1356          to pcre_exec() should be used to pass in a tables address if a value
1357          other than the default internal tables were used at compile time.
1359    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1360        now diagnosed as an error. Previously, most of the time, a negative number
1361        would have been treated as zero, but if in addition "ovector" was passed as
1362        NULL, a crash could occur.
1364    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1365        new versions from the libtool 1.5 distribution (the last one is a copy of
1366        a file called libtool.m4). This seems to have fixed the need to patch
1367        "configure" to support Darwin 1.3 (which I used to do). However, I still
1368        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1369        workstation).
1371    24. Changed the PCRE licence to be the more standard "BSD" licence.
1374    Version 4.5 01-Dec-03
1375    ---------------------
1377     1. There has been some re-arrangement of the code for the match() function so
1378        that it can be compiled in a version that does not call itself recursively.
1379        Instead, it keeps those local variables that need separate instances for
1380        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1381        needs to "recurse". Keeping track of where control must go is done by means
1382        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1383        hide most of the details from the main code, and operates only if
1384        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1385        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1386        operating.
1388        To make it easier for callers to provide specially tailored get/free
1389        functions for this usage, two new functions, pcre_stack_malloc, and
1390        pcre_stack_free, are used. They are always called in strict stacking order,
1391        and the size of block requested is always the same.
1393        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1394        PCRE has been compiled to use the stack or the heap for recursion. The
1395        -C option of pcretest uses this to show which version is compiled.
1397        A new data escape \S, is added to pcretest; it causes the amounts of store
1398        obtained and freed by both kinds of malloc/free at match time to be added
1399        to the output.
1401     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1402        what's available on my current Linux desktop machine.
1404     3. When matching a UTF-8 string, the test for a valid string at the start has
1405        been extended. If start_offset is not zero, PCRE now checks that it points
1406        to a byte that is the start of a UTF-8 character. If not, it returns
1407        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1408        this is necessary because there may be backward assertions in the pattern.
1409        When matching the same subject several times, it may save resources to use
1410        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1412     4. The code for checking the validity of UTF-8 strings has been tightened so
1413        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1414        containing "overlong sequences".
1416     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1417        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1418        should have been "&", but it just so happened that all the cases this let
1419        through by mistake were picked up later in the function.
1421     6. I had used a variable called "isblank" - this is a C99 function, causing
1422        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1424     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1425        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1426        so the version is shown; (c) stop "make test" echoing "./RunTest".
1428     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1430     9. The prototype for memmove() for systems that don't have it was using
1431        size_t, but the inclusion of the header that defines size_t was later. I've
1432        moved the #includes for the C headers earlier to avoid this.
1434    10. Added some adjustments to the code to make it easier to compiler on certain
1435        special systems:
1437          (a) Some "const" qualifiers were missing.
1438          (b) Added the macro EXPORT before all exported functions; by default this
1439              is defined to be empty.
1440          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1441              that it reads its output file name as an argument instead of writing
1442              to the standard output and assuming this can be redirected.
1444    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1445        class containing characters with values greater than 255, PCRE compilation
1446        went into a loop.
1448    12. A recursive reference to a subpattern that was within another subpattern
1449        that had a minimum quantifier of zero caused PCRE to crash. For example,
1450        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1451        recursion. If the recursively-called subpattern itself had a zero repeat,
1452        that was OK.
1454    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1455        buffer into which it was copied (for escape processing) was still set at
1456        1024, so long lines caused crashes.
1458    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1459        "internal error: code overflow...". This applied to any character class
1460        that was followed by a possessive quantifier.
1462    15. Modified the Makefile to add libpcre.la as a prerequisite for
1463        libpcreposix.la because I was told this is needed for a parallel build to
1464        work.
1466    16. If a pattern that contained .* following optional items at the start was
1467        studied, the wrong optimizing data was generated, leading to matching
1468        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1469        matching string must start with a or b or c. The correct conclusion for
1470        this pattern is that a match can start with any character.
1473    Version 4.4 13-Aug-03
1474    ---------------------
1476     1. In UTF-8 mode, a character class containing characters with values between
1477        127 and 255 was not handled correctly if the compiled pattern was studied.
1478        In fixing this, I have also improved the studying algorithm for such
1479        classes (slightly).
1481     2. Three internal functions had redundant arguments passed to them. Removal
1482        might give a very teeny performance improvement.
1484     3. Documentation bug: the value of the capture_top field in a callout is *one
1485        more than* the number of the hightest numbered captured substring.
1487     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1488        in incorrectly linking with a previously installed version. They now link
1489        explicitly with libpcre.la.
1491     5. configure.in no longer needs to recognize Cygwin specially.
1493     6. A problem in pcre.in for Windows platforms is fixed.
1495     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1496        pcretest, it used to include the size of the study block as part of its
1497        output. Unfortunately, the structure contains a field that has a different
1498        size on different hardware architectures. This meant that the tests that
1499        showed this size failed. As the block is currently always of a fixed size,
1500        this information isn't actually particularly useful in pcretest output, so
1501        I have just removed it.
1503     8. Three pre-processor statements accidentally did not start in column 1.
1504        Sadly, there are *still* compilers around that complain, even though
1505        standard C has not required this for well over a decade. Sigh.
1507     9. In pcretest, the code for checking callouts passed small integers in the
1508        callout_data field, which is a void * field. However, some picky compilers
1509        complained about the casts involved for this on 64-bit systems. Now
1510        pcretest passes the address of the small integer instead, which should get
1511        rid of the warnings.
1513    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1514        both compile and run time, and gives an error if an invalid UTF-8 sequence
1515        is found. There is a option for disabling this check in cases where the
1516        string is known to be correct and/or the maximum performance is wanted.
1518    11. In response to a bug report, I changed one line in Makefile.in from
1520            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1521        to
1522            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1524        to look similar to other lines, but I have no way of telling whether this
1525        is the right thing to do, as I do not use Windows. No doubt I'll get told
1526        if it's wrong...
1529    Version 4.3 21-May-03
1530    ---------------------
1532    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1533       Makefile.
1535    2. Some refactoring to improve the quality of the code:
1537       (i)   The utf8_table... variables are now declared "const".
1539       (ii)  The code for \cx, which used the "case flipping" table to upper case
1540             lower case letters, now just substracts 32. This is ASCII-specific,
1541             but the whole concept of \cx is ASCII-specific, so it seems
1542             reasonable.
1544       (iii) PCRE was using its character types table to recognize decimal and
1545             hexadecimal digits in the pattern. This is silly, because it handles
1546             only 0-9, a-f, and A-F, but the character types table is locale-
1547             specific, which means strange things might happen. A private
1548             table is now used for this - though it costs 256 bytes, a table is
1549             much faster than multiple explicit tests. Of course, the standard
1550             character types table is still used for matching digits in subject
1551             strings against \d.
1553       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1554             ending in _t are). So I've renamed it as ESC_tee.
1556    3. The first argument for regexec() in the POSIX wrapper should have been
1557       defined as "const".
1559    4. Changed pcretest to use malloc() for its buffers so that they can be
1560       Electric Fenced for debugging.
1562    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1563       to read one or more bytes before the start of the subject string. Often this
1564       had no effect on PCRE's behaviour, but in some circumstances it could
1565       provoke a segmentation fault.
1567    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1568       to try to read one or more bytes before the start of the subject string.
1570    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1571       UTF-8 support could misbehave in various ways if the subject string
1572       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1573       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1574       back over UTF-8 characters.)
1577    Version 4.2 14-Apr-03
1578    ---------------------
1580    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1582    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1583         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1584         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1585         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1586         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1587           and BUILD_EXEEXT
1588         Note: automatic setting of the BUILD variables is not yet working
1589         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1590           compile-time but not at link-time
1591         [LINK]: use for linking executables only
1592         make different versions for Windows and non-Windows
1593         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1594           libraries
1595         [LINK_FOR_BUILD]: new variable
1596         [OBJEXT]: use throughout
1597         [EXEEXT]: use throughout
1598         <winshared>: new target
1599         <wininstall>: new target
1600         <dftables.o>: use native compiler
1601         <dftables>: use native linker
1602         <install>: handle Windows platform correctly
1603         <clean>: ditto
1604         <check>: ditto
1605         copy DLL to top builddir before testing
1607       As part of these changes, -no-undefined was removed again. This was reported
1608       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1609       in any case.
1611    3. Some tidies to get rid of compiler warnings:
1613       . In the match_data structure, match_limit was an unsigned long int, whereas
1614         match_call_count was an int. I've made them both unsigned long ints.
1616       . In pcretest the fact that a const uschar * doesn't automatically cast to
1617         a void * provoked a warning.
1619       . Turning on some more compiler warnings threw up some "shadow" variables
1620         and a few more missing casts.
1622    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1623       option, a class that contained a single character with a value between 128
1624       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1626    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1627       option, a class that contained several characters, but with at least one
1628       whose value was between 128 and 255 caused PCRE to crash.
1631    Version 4.1 12-Mar-03
1632    ---------------------
1634    1. Compiling with gcc -pedantic found a couple of places where casts were
1635    needed, and a string in dftables.c that was longer than standard compilers are
1636    required to support.
1638    2. Compiling with Sun's compiler found a few more places where the code could
1639    be tidied up in order to avoid warnings.
1641    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1642    first of these names is deprecated in the latest Autoconf in favour of the name
1643    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1644    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1645    analogy I have changed it to CFLAGS_FOR_BUILD.
1647    4. Added -no-undefined to the linking command in the Makefile, because this is
1648    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1649    linking step for the pcreposix library.
1651    5. PCRE was failing to diagnose the case of two named groups with the same
1652    name.
1654    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1655    literal character that is needed in the subject for a match, and scans along to
1656    ensure that it is present before embarking on the full matching process. This
1657    saves time in cases of nested unlimited repeats that are never going to match.
1658    Problem: the scan can take a lot of time if the subject is very long (e.g.
1659    megabytes), thus penalizing straightforward matches. It is now done only if the
1660    amount of subject to be scanned is less than 1000 bytes.
1662    7. A lesser problem with the same optimization is that it was recording the
1663    first character of an anchored pattern as "needed", thus provoking a search
1664    right along the subject, even when the first match of the pattern was going to
1665    fail. The "needed" character is now not set for anchored patterns, unless it
1666    follows something in the pattern that is of non-fixed length. Thus, it still
1667    fulfils its original purpose of finding quick non-matches in cases of nested
1668    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1671    Version 4.0 17-Feb-03
1672    ---------------------
1674    1. If a comment in an extended regex that started immediately after a meta-item
1675    extended to the end of string, PCRE compiled incorrect data. This could lead to
1676    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1678    2. Moved to autoconf 2.53 and libtool 1.4.2.
1680    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1681    the special perltest8 script is no longer needed - all the tests can be run
1682    from a single perltest script.
1684    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1685    by \s. It has now been removed in PCRE. This means it isn't recognized as
1686    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1687    class [:space:] *does* include VT, thereby creating a mess.
1689    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1690    space and tab.
1692    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1693    its new features into the main test script, reducing the number of scripts.
1695    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1696    were backward compatible, and made the (?i) apply to the whole pattern, as if
1697    /i were given. Now it behaves more logically, and applies the option setting
1698    only to what follows. PCRE has been changed to follow suit. However, if it
1699    finds options settings right at the start of the pattern, it extracts them into
1700    the global options, as before. Thus, they show up in the info data.
1702    8. Added support for the \Q...\E escape sequence. Characters in between are
1703    treated as literals. This is slightly different from Perl in that $ and @ are
1704    also handled as literals inside the quotes. In Perl, they will cause variable
1705    interpolation. Note the following examples:
1707        Pattern            PCRE matches      Perl matches
1709        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1710        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1711        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1713    For compatibility with Perl, \Q...\E sequences are recognized inside character
1714    classes as well as outside them.
1716    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1717    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1718    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1719    signed/unsigned warnings.
1721    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1722    option for pcretest, so I've replaced it by a simple function that does just
1723    that job.
1725    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1726    "pcregrep -".
1728    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1729    Java package. This provides some syntactic sugar for simple cases of what my
1730    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1731    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1732    item, you can use this simplified notation. Note that only makes sense with
1733    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1734    greediness, whatever the setting of the PCRE_UNGREEDY option.
1736    13. A change of greediness default within a pattern was not taking effect at
1737    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1738    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1739    was abstracted outside.
1741    14. PCRE now supports the \G assertion. It is true when the current matching
1742    position is at the start point of the match. This differs from \A when the
1743    starting offset is non-zero. Used with the /g option of pcretest (or similar
1744    code), it works in the same way as it does for Perl's /g option. If all
1745    alternatives of a regex begin with \G, the expression is anchored to the start
1746    match position, and the "anchored" flag is set in the compiled expression.
1748    15. Some bugs concerning the handling of certain option changes within patterns
1749    have been fixed. These applied to options other than (?ims). For example,
1750    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1751    been the other way round. Some of this was related to change 7 above.
1753    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1754    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1755    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1756    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1758    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1759    mode. Unlike ".", it always matches newline, whatever the setting of
1760    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1761    assertions. Perl allows it, but it doesn't (in general) work because it can't
1762    calculate the length of the lookbehind. At least, that's the case for Perl
1763    5.8.0 - I've been told they are going to document that it doesn't work in
1764    future.
1766    18. Added an error diagnosis for escapes that PCRE does not support: these are
1767    \L, \l, \N, \P, \p, \U, \u, and \X.
1769    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1770    reading past the end of the pattern in cases such as /[abcd/.
1772    20. PCRE was getting more memory than necessary for patterns with classes that
1773    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1775    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1776    compiling PCRE for use with Virtual Pascal.
1778    22. Small fix to the Makefile to make it work properly if the build is done
1779    outside the source tree.
1781    23. Added a new extension: a condition to go with recursion. If a conditional
1782    subpattern starts with (?(R) the "true" branch is used if recursion has
1783    happened, whereas the "false" branch is used only at the top level.
1785    24. When there was a very long string of literal characters (over 255 bytes
1786    without UTF support, over 250 bytes with UTF support), the computation of how
1787    much memory was required could be incorrect, leading to segfaults or other
1788    strange effects.
1790    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1791    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1792    there was a subsequent back reference to those brackets. This meant that, for
1793    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1794    possible to check for precisely this case. All we can do is abandon the
1795    optimization if .* occurs inside capturing brackets when there are any back
1796    references whatsoever. (See below for a better fix that came later.)
1798    26. The handling of the optimization for finding the first character of a
1799    non-anchored pattern, and for finding a character that is required later in the
1800    match were failing in some cases. This didn't break the matching; it just
1801    failed to optimize when it could. The way this is done has been re-implemented.
1803    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1805    28. Added a new feature that provides some of the functionality that Perl
1806    provides with (?{...}). The facility is termed a "callout". The way it is done
1807    in PCRE is for the caller to provide an optional function, by setting
1808    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1809    global variable. By default it is unset, which disables all calling out. To get
1810    the function called, the regex must include (?C) at appropriate points. This
1811    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1812    This provides a means of identifying different callout points. When PCRE
1813    reaches such a point in the regex, if pcre_callout has been set, the external
1814    function is called. It is provided with data in a structure called
1815    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1816    matching continues; if it returns a non-zero value, the match at the current
1817    point fails. However, backtracking will occur if possible. [This was changed
1818    later and other features added - see item 49 below.]
1820    29. pcretest is upgraded to test the callout functionality. It provides a
1821    callout function that displays information. By default, it shows the start of
1822    the match and the current position in the text. There are some new data escapes
1823    to vary what happens:
1825        \C+         in addition, show current contents of captured substrings
1826        \C-         do not supply a callout function
1827        \C!n        return 1 when callout number n is reached
1828        \C!n!m      return 1 when callout number n is reached for the mth time
1830    30. If pcregrep was called with the -l option and just a single file name, it
1831    output "<stdin>" if a match was found, instead of the file name.
1833    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1834    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1835    pcre_exec(). This saves a malloc/free per call. The default value of
1836    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1837    when configuring.
1839    32. The default maximum size of a compiled pattern is 64K. There have been a
1840    few cases of people hitting this limit. The code now uses macros to handle the
1841    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1842    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1843    configuring. Tests 2 and 5 work only with 2-byte links because they output
1844    debugging information about compiled patterns.
1846    33. Internal code re-arrangements:
1848    (a) Moved the debugging function for printing out a compiled regex into
1849        its own source file (printint.c) and used #include to pull it into
1850        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1851        separate copies.
1853    (b) Defined the list of op-code names for debugging as a macro in
1854        internal.h so that it is next to the definition of the opcodes.
1856    (c) Defined a table of op-code lengths for simpler skipping along compiled
1857        code. This is again a macro in internal.h so that it is next to the
1858        definition of the opcodes.
1860    34. Added support for recursive calls to individual subpatterns, along the
1861    lines of Robin Houston's patch (but implemented somewhat differently).
1863    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1864    allow it to read and process whole directories in Win32. This code was
1865    contributed by Lionel Fourquaux; it has not been tested by me.
1867    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1868    used to name a group. Names consist of alphanumerics and underscores, and must
1869    be unique. Back references use the syntax (?P=name) and recursive calls use
1870    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1871    numbers. The function pcre_fullinfo() can be used after compilation to extract
1872    a name/number map. There are three relevant calls:
1874      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1875      PCRE_INFO_NAMECOUNT            yields the number of entries
1876      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1878    The map is a vector of fixed-size entries. The size of each entry depends on
1879    the length of the longest name used. The first two bytes of each entry are the
1880    group number, most significant byte first. There follows the corresponding
1881    name, zero terminated. The names are in alphabetical order.
1883    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1884    case instead of 255. Making it the same both with and without UTF-8 support
1885    means that the same test output works with both.
1887    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1888    calling malloc() with a zero argument.
1890    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1891    optimization. I've improved things by keeping a bitmap of backreferences with
1892    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1893    fact referenced, the optimization can be applied. It is unlikely that a
1894    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1895    the match to follow \n) will appear inside brackets with a number greater than
1896    31, but if it does, any back reference > 31 suppresses the optimization.
1898    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1899    of disabling numbered capturing parentheses. Any opening parenthesis that is
1900    not followed by ? behaves as if it were followed by ?: but named parentheses
1901    can still be used for capturing (and they will acquire numbers in the usual
1902    way).
1904    41. Redesigned the return codes from the match() function into yes/no/error so
1905    that errors can be passed back from deep inside the nested calls. A malloc
1906    failure while inside a recursive subpattern call now causes the
1907    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1909    42. It is now possible to set a limit on the number of times the match()
1910    function is called in a call to pcre_exec(). This facility makes it possible to
1911    limit the amount of recursion and backtracking, though not in a directly
1912    obvious way, because the match() function is used in a number of different
1913    circumstances. The count starts from zero for each position in the subject
1914    string (for non-anchored patterns). The default limit is, for compatibility, a
1915    large number, namely 10 000 000. You can change this in two ways:
1917    (a) When configuring PCRE before making, you can use --with-match-limit=n
1918        to set a default value for the compiled library.
1920    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1921        a different value is set. See 45 below.
1923    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1925    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1926    of things that can be changed at compile time. The first argument specifies
1927    what is wanted and the second points to where the information is to be placed.
1928    The current list of available information is:
1930      PCRE_CONFIG_UTF8
1932    The output is an integer that is set to one if UTF-8 support is available;
1933    otherwise it is set to zero.
1937    The output is an integer that it set to the value of the code that is used for
1938    newline. It is either LF (10) or CR (13).
1942    The output is an integer that contains the number of bytes used for internal
1943    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1947    The output is an integer that contains the threshold above which the POSIX
1948    interface uses malloc() for output vectors. See item 31 above.
1952    The output is an unsigned integer that contains the default limit of the number
1953    of match() calls in a pcre_exec() execution. See 42 above.
1955    44. pcretest has been upgraded by the addition of the -C option. This causes it
1956    to extract all the available output from the new pcre_config() function, and to
1957    output it. The program then exits immediately.
1959    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1960    order to support additional features. One way would have been to define
1961    pcre_exec2() (for example) with extra arguments, but this would not have been
1962    extensible, and would also have required all calls to the original function to
1963    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1964    is used for passing in "extra" data from pcre_study().
1966    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1967    contains the following fields:
1969      flags         a bitmap indicating which of the following fields are set
1970      study_data    opaque data from pcre_study()
1971      match_limit   a way of specifying a limit on match() calls for a specific
1972                      call to pcre_exec()
1973      callout_data  data for callouts (see 49 below)
1975    The flag bits are also defined in pcre.h, and are
1981    The pcre_study() function now returns one of these new pcre_extra blocks, with
1982    the actual study data pointed to by the study_data field, and the
1983    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1984    before. That is, this change is entirely upwards-compatible and requires no
1985    change to existing code.
1987    If you want to pass in additional data to pcre_exec(), you can either place it
1988    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1989    block.
1991    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1992    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1993    times with different match limits, until it finds the minimum value needed for
1994    pcre_exec() to complete. The value is then output. This can be instructive; for
1995    most simple matches the number is quite small, but for pathological cases it
1996    gets very large very quickly.
1998    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1999    returns the size of the data block pointed to by the study_data field in a
2000    pcre_extra block, that is, the value that was passed as the argument to
2001    pcre_malloc() when PCRE was getting memory in which to place the information
2002    created by pcre_study(). The fourth argument should point to a size_t variable.
2003    pcretest has been extended so that this information is shown after a successful
2004    pcre_study() call when information about the compiled regex is being displayed.
2006    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2007    because what follows is always an absolute path. (Later: it turns out that this
2008    is more than cosmetic for MinGW, because it doesn't like empty path
2009    components.)
2011    49. Some changes have been made to the callout feature (see 28 above):
2013    (i)  A callout function now has three choices for what it returns:
2015           0  =>  success, carry on matching
2016         > 0  =>  failure at this point, but backtrack if possible
2017         < 0  =>  serious error, return this value from pcre_exec()
2019         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2020         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2021         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2022         use by callout functions. It will never be used by PCRE itself.
2024    (ii) The pcre_extra structure (see 45 above) has a void * field called
2025         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2026         pcre_callout_block structure has a field of the same name. The contents of
2027         the field passed in the pcre_extra structure are passed to the callout
2028         function in the corresponding field in the callout block. This makes it
2029         easier to use the same callout-containing regex from multiple threads. For
2030         testing, the pcretest program has a new data escape
2032           \C*n        pass the number n (may be negative) as callout_data
2034         If the callout function in pcretest receives a non-zero value as
2035         callout_data, it returns that value.
2037    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2038    there were some redundant $(CFLAGS) in commands that are now specified as
2039    $(LINK), which already includes $(CFLAGS).
2041    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2042    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2043    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2044    one-byte characters throughout. Note that case-insensitive matching applies
2045    only to characters whose values are less than 256. PCRE doesn't support the
2046    notion of cases for higher-valued characters.
2048    (i)   A character class whose characters are all within 0-255 is handled as
2049          a bit map, and the map is inverted for negative classes. Previously, a
2050          character > 255 always failed to match such a class; however it should
2051          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2053    (ii)  A negated character class with a single character < 255 is coded as
2054          "not this character" (OP_NOT). This wasn't working properly when the test
2055          character was multibyte, either singly or repeated.
2057    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2058          mode, for example: \x{100}{2,3}.
2060    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2061          singly or repeated) now correctly test multibyte characters. However,
2062          PCRE doesn't recognize any characters with values greater than 255 as
2063          digits, spaces, or word characters. Such characters always match \D, \S,
2064          and \W, and never match \d, \s, or \w.
2066    (v)   Classes may now contain characters and character ranges with values
2067          greater than 255. For example: [ab\x{100}-\x{400}].
2069    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2070          PCRE in UTF-8 mode.
2072    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2073    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2074    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2075    value.)
2077    53. The single man page has become too large. I have therefore split it up into
2078    a number of separate man pages. These also give rise to individual HTML pages;
2079    these are now put in a separate directory, and there is an index.html page that
2080    lists them all. Some hyperlinking between the pages has been installed.
2082    54. Added convenience functions for handling named capturing parentheses.
2084    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2085    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2086    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2087    are faulted.
2089    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2090    calling configure. These values are used when compiling the dftables.c program
2091    which is run to generate the source of the default character tables. They
2092    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2093    you will need to set these values.
2095    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2098    Version 3.9 02-Jan-02
2099    ---------------------
2101    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2103    2. If --disable-static was given, the building process failed when trying to
2104    build pcretest and pcregrep. (For some reason it was using libtool to compile
2105    them, which is not right, as they aren't part of the library.)
2108    Version 3.8 18-Dec-01
2109    ---------------------
2111    1. The experimental UTF-8 code was completely screwed up. It was packing the
2112    bytes in the wrong order. How dumb can you get?
2115    Version 3.7 29-Oct-01
2116    ---------------------
2118    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2119    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2120    this didn't happen under Solaris 8, where I normally test things.
2122    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2123    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2124    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2125    this fix an hour or so after the initial 3.7 release.)
2128    Version 3.6 23-Oct-01
2129    ---------------------
2131    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2132    offsets passed as NULL with zero offset count.
2134    2. The config.guess and config.sub files had not been updated when I moved to
2135    the latest autoconf.
2138    Version 3.5 15-Aug-01
2139    ---------------------
2141    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2142    had been forgotten.
2144    2. By using declared but undefined structures, we can avoid using "void"
2145    definitions in pcre.h while keeping the internal definitions of the structures
2146    private.
2148    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2149    user point of view, this means that both static and shared libraries are built
2150    by default, but this can be individually controlled. More of the work of
2151    handling this static/shared cases is now inside libtool instead of PCRE's make
2152    file.
2154    4. The pcretest utility is now installed along with pcregrep because it is
2155    useful for users (to test regexs) and by doing this, it automatically gets
2156    relinked by libtool. The documentation has been turned into a man page, so
2157    there are now .1, .txt, and .html versions in /doc.
2159    5. Upgrades to pcregrep:
2160       (i)   Added long-form option names like gnu grep.
2161       (ii)  Added --help to list all options with an explanatory phrase.
2162       (iii) Added -r, --recursive to recurse into sub-directories.
2163       (iv)  Added -f, --file to read patterns from a file.
2165    6. pcre_exec() was referring to its "code" argument before testing that
2166    argument for NULL (and giving an error if it was NULL).
2168    7. Upgraded Makefile.in to allow for compiling in a different directory from
2169    the source directory.
2171    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2172    options bits, the pointer it was passed was to an int instead of to an unsigned
2173    long int. This mattered only on 64-bit systems.
2175    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2176    generated) instead of pcre.in, which it its source. Also made the same change
2177    in several of the .c files.
2179    10. A new release of gcc defines printf() as a macro, which broke pcretest
2180    because it had an ifdef in the middle of a string argument for printf(). Fixed
2181    by using separate calls to printf().
2183    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2184    script, to force use of CR or LF instead of \n in the source. On non-Unix
2185    systems, the value can be set in config.h.
2187    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2188    absolute limit. Changed the text of the error message to make this clear, and
2189    likewise updated the man page.
2191    13. The limit of 99 on the number of capturing subpatterns has been removed.
2192    The new limit is 65535, which I hope will not be a "real" limit.
2195    Version 3.4 22-Aug-00
2196    ---------------------
2198    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2200    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2203    Version 3.3 01-Aug-00
2204    ---------------------
2206    1. If an octal character was given, but the value was greater than \377, it
2207    was not getting masked to the least significant bits, as documented. This could
2208    lead to crashes in some systems.
2210    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2211    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2213    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2214    These just pass their arguments on to (pcre_free)(), but they are provided
2215    because some uses of PCRE bind it to non-C systems that can call its functions,
2216    but cannot call free() or pcre_free() directly.
2218    4. Add "make test" as a synonym for "make check". Corrected some comments in
2219    the Makefile.
2221    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2222    Makefile.
2224    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2225    command called pgrep for grepping around the active processes.
2227    7. Added the beginnings of support for UTF-8 character strings.
2229    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2230    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2231    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2232    out for the ar command.)
2235    Version 3.2 12-May-00
2236    ---------------------
2238    This is purely a bug fixing release.
2240    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2241    of ZA. This was just one example of several cases that could provoke this bug,
2242    which was introduced by change 9 of version 2.00. The code for breaking
2243    infinite loops after an iteration that matches an empty string was't working
2244    correctly.
2246    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2247    when matched against abbab (for example). After matching an empty string, it
2248    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2249    caused it to match further down the string than it should.
2251    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2252    was there because it doesn't seem to be needed, and it causes trouble on some
2253    systems, as it is not a Standard C header. It has been removed.
2255    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2256    were reported on the Macintosh. The changes were from
2258      while ((c = *(++ptr)) != 0 && c != '\n');
2259    to
2260      while ((c = *(++ptr)) != 0 && c != '\n') ;
2262    Totally extraordinary, but if that's what it takes...
2264    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2265    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2266    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2267    assumes the way PCRE uses memmove() (always moving upwards).
2269    6. PCRE is being used in one environment where strchr() is not available. There
2270    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2271    faster code anyway.
2274    Version 3.1 09-Feb-00
2275    ---------------------
2277    The only change in this release is the fixing of some bugs in Makefile.in for
2278    the "install" target:
2280    (1) It was failing to install pcreposix.h.
2282    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2285    Version 3.0 01-Feb-00
2286    ---------------------
2288    1. Add support for the /+ modifier to perltest (to output $` like it does in
2289    pcretest).
2291    2. Add support for the /g modifier to perltest.
2293    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2294    matches null strings.
2296    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2297    pattern. Perl treats empty patterns specially - it reuses the most recent
2298    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2299    effect.
2301    5. The POSIX interface was broken in that it was just handing over the POSIX
2302    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2303    required a bigger vector, with some working space on the end. This means that
2304    the POSIX wrapper now has to get and free some memory, and copy the results.
2306    6. Added some simple autoconf support, placing the test data and the
2307    documentation in separate directories, re-organizing some of the
2308    information files, and making it build pcre-config (a GNU standard). Also added
2309    libtool support for building PCRE as a shared library, which is now the
2310    default.
2312    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2313    09 are not valid octal constants. Single digits will be used for minor values
2314    less than 10.
2316    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2317    existing programs that set these in the POSIX interface can use PCRE without
2318    modification.
2320    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2321    return all that pcre_info() returns, plus additional data. The pcre_info()
2322    function is retained for compatibility, but is considered to be obsolete.
2324    10. Added experimental recursion feature (?R) to handle one common case that
2325    Perl 5.6 will be able to do with (?p{...}).
2327    11. Added support for POSIX character classes like [:alpha:], which Perl is
2328    adopting.
2331    Version 2.08 31-Aug-99
2332    ----------------------
2334    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2335    trying to match at the startoffset position, but instead was moving forward to
2336    the next newline as if a previous match had failed.
2338    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2339    and could get into a loop if a null string was matched other than at the start
2340    of the subject.
2342    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2343    be distinguished at compile time, and for completeness also added PCRE_DATE.
2345    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2346    in GnuWin32 environments.
2349    Version 2.07 29-Jul-99
2350    ----------------------
2352    1. The documentation is now supplied in plain text form and HTML as well as in
2353    the form of man page sources.
2355    2. C++ compilers don't like assigning (void *) values to other pointer types.
2356    In particular this affects malloc(). Although there is no problem in Standard
2357    C, I've put in casts to keep C++ compilers happy.
2359    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2360    should be (const char *).
2362    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2363    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2364    However, I haven't made this a standard facility. The documentation doesn't
2365    mention it, and the Makefile doesn't support it.
2367    5. The Makefile now contains an "install" target, with editable destinations at
2368    the top of the file. The pcretest program is not installed.
2370    6. pgrep -V now gives the PCRE version number and date.
2372    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2373    causing the entire string to be ignored, instead of just the last character.
2375    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2376    non-matching string, it can take a very, very long time, even for strings of
2377    quite modest length, because of the nested recursion. PCRE now does better in
2378    some of these cases. It does this by remembering the last required literal
2379    character in the pattern, and pre-searching the subject to ensure it is present
2380    before running the real match. In other words, it applies a heuristic to detect
2381    some types of certain failure quickly, and in the above example, if presented
2382    with a string that has no trailing " it gives "no match" very quickly.
2384    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2385    other alternatives are tried instead.
2388    Version 2.06 09-Jun-99
2389    ----------------------
2391    1. Change pcretest's output for amount of store used to show just the code
2392    space, because the remainder (the data block) varies in size between 32-bit and
2393    64-bit systems.
2395    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2396    start matching at. This allows lookbehinds to work when searching for multiple
2397    occurrences in a string.
2399    3. Added additional options to pcretest for testing multiple occurrences:
2401       /+   outputs the rest of the string that follows a match
2402       /g   loops for multiple occurrences, using the new startoffset argument
2403       /G   loops for multiple occurrences by passing an incremented pointer
2405    4. PCRE wasn't doing the "first character" optimization for patterns starting
2406    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2407    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2408    the letter 'x'. On long subject strings, this gives a significant speed-up.
2411    Version 2.05 21-Apr-99
2412    ----------------------
2414    1. Changed the type of magic_number from int to long int so that it works
2415    properly on 16-bit systems.
2417    2. Fixed a bug which caused patterns starting with .* not to work correctly
2418    when the subject string contained newline characters. PCRE was assuming
2419    anchoring for such patterns in all cases, which is not correct because .* will
2420    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2421    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2422    must be retried after every newline in the subject.
2425    Version 2.04 18-Feb-99
2426    ----------------------
2428    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2429    computation of the store needed to hold the pattern was incorrect (too large).
2430    If such patterns were nested a few deep, this could multiply and become a real
2431    problem.
2433    2. Added /M option to pcretest to show the memory requirement of a specific
2434    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2436    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2437    compiled in such a way that the backtracking after subsequent failure was
2438    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2439    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2442    Version 2.03 02-Feb-99
2443    ----------------------
2445    1. Fixed typo and small mistake in man page.
2447    2. Added 4th condition (GPL supersedes if conflict) and created separate
2448    LICENCE file containing the conditions.
2450    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2451    Perl, that is the internal \ allows the delimiter to be included in the
2452    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2453    the final delimiter, add \ to the end of the pattern (to test the error).
2455    4. Added the convenience functions for extracting substrings after a successful
2456    match. Updated pcretest to make it able to test these functions.
2459    Version 2.02 14-Jan-99
2460    ----------------------
2462    1. Initialized the working variables associated with each extraction so that
2463    their saving and restoring doesn't refer to uninitialized store.
2465    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2466    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2467    fix the problem.
2469    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2470    calls, and wasn't printing the correct value for compiling calls. Increased the
2471    default value of LOOPREPEAT, and the number of significant figures in the
2472    times.
2474    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2476    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2477    a building problem on Windows NT with a FAT file system.
2480    Version 2.01 21-Oct-98
2481    ----------------------
2483    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2484    to character tables built by pcre_maketables() in the current locale. If NULL
2485    is passed, the default tables are used.
2488    Version 2.00 24-Sep-98
2489    ----------------------
2491    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2492    it any more.
2494    2. Allow quantification of (?>) groups, and make it work correctly.
2496    3. The first character computation wasn't working for (?>) groups.
2498    4. Correct the implementation of \Z (it is permitted to match on the \n at the
2499    end of the subject) and add 5.005's \z, which really does match only at the
2500    very end of the subject.
2502    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2504    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2505    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2506    localized options. All options to pcre_study() were also removed.
2508    7. Add other new features from 5.005:
2510       $(?<=           positive lookbehind
2511       $(?<!           negative lookbehind
2512       (?imsx-imsx)    added the unsetting capability
2513                       such a setting is global if at outer level; local otherwise
2514       (?imsx-imsx:)   non-capturing groups with option setting
2515       (?(cond)re|re)  conditional pattern matching
2517       A backreference to itself in a repeated group matches the previous
2518       captured string.
2520    8. General tidying up of studying (both automatic and via "study")
2521    consequential on the addition of new assertions.
2523    9. As in 5.005, unlimited repeated groups that could match an empty substring
2524    are no longer faulted at compile time. Instead, the loop is forcibly broken at
2525    runtime if any iteration does actually match an empty substring.
2527    10. Include the RunTest script in the distribution.
2529    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2530    discrepancies, some of which were old and were also with respect to 5.004. They
2531    have now been fixed.
2534    Version 1.09 28-Apr-98
2535    ----------------------
2537    1. A negated single character class followed by a quantifier with a minimum
2538    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
2539    program crashes, or just wrong answers. This did not apply to negated classes
2540    containing more than one character, or to minima other than one.
2543  Version 1.08 27-Mar-98  Version 1.08 27-Mar-98
2544  ----------------------  ----------------------

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