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revision 33 by nigel, Sat Feb 24 21:39:01 2007 UTC revision 390 by ph10, Tue Mar 17 10:58:16 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.9 xx-xxx-09
5    ---------------------
7    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
8        (pcretest), all targets were linked against these libraries. This included
9        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
10        libraries. This caused unwanted dependencies to be created. This problem
11        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
12        pcretest is linked with readline.
14    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
15        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
16        moved outside it again, because FALSE and TRUE are already defined in AIX,
17        but BOOL is not.
19    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
20        PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.
22    4.  The pcregrep documentation said spaces were inserted as well as colons (or
23        hyphens) following file names and line numbers when outputting matching
24        lines. This is not true; no spaces are inserted. I have also clarified the
25        wording for the --colour (or --color) option.
27    5.  In pcregrep, when --colour was used with -o, the list of matching strings
28        was not coloured; this is different to GNU grep, so I have changed it to be
29        the same.
31    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
32        each matching line was coloured. Now it goes on to look for further matches
33        of any of the test patterns, which is the same behaviour as GNU grep.
35    7.  A pattern that could match an empty string could cause pcregrep to loop; it
36        doesn't make sense to accept an empty string match in pcregrep, so I have
37        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
38        seems to be how GNU grep behaves.
40    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
41        start or after a newline", because the conditional assertion was not being
42        correctly handled. The rule now is that both the assertion and what follows
43        in the first alternative must satisfy the test.
45    9.  If auto-callout was enabled in a pattern with a conditional group, PCRE
46        could crash during matching.
48    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
49        used for matching.
51    11. Unicode property support in character classes was not working for
52        characters (bytes) greater than 127 when not in UTF-8 mode.
54    12. Added the -M command line option to pcretest.
56    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
58    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
60    16. Added comments and documentation about mis-use of no_arg in the C++
61        wrapper.
64    Version 7.8 05-Sep-08
65    ---------------------
67    1.  Replaced UCP searching code with optimized version as implemented for Ad
68        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
69        stage table and inline lookup instead of a function, giving speed ups of 2
70        to 5 times on some simple patterns that I tested. Permission was given to
71        distribute the MultiStage2.py script that generates the tables (it's not in
72        the tarball, but is in the Subversion repository).
74    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
75        scripts.
77    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
78        a group with a zero qualifier. The result of the study could be incorrect,
79        or the function might crash, depending on the pattern.
81    4.  Caseless matching was not working for non-ASCII characters in back
82        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
83        It now works when Unicode Property Support is available.
85    5.  In pcretest, an escape such as \x{de} in the data was always generating
86        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
87        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
88        truncation.
90    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
92    7.  Added two (int) casts to pcregrep when printing the difference of two
93        pointers, in case they are 64-bit values.
95    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
96        test 2 if it fails.
98    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
99        and a #define of that name to empty if it is not externally set. This is to
100        allow users of MSVC to set it if necessary.
102    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
103        the convenience functions in the pcre_get.c source file.
105    11. An option change at the start of a pattern that had top-level alternatives
106        could cause overwriting and/or a crash. This command provoked a crash in
107        some environments:
109          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
111        This potential security problem was recorded as CVE-2008-2371.
113    12. For a pattern where the match had to start at the beginning or immediately
114        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
115        pcre_dfa_exec() could read past the end of the passed subject if there was
116        no match. To help with detecting such bugs (e.g. with valgrind), I modified
117        pcretest so that it places the subject at the end of its malloc-ed buffer.
119    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
120        exec() might read past the end of the data buffer in UTF-8 mode.
122    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
123        the data contained the byte 0x85 as part of a UTF-8 character within its
124        first line. This applied both to normal and DFA matching.
126    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
127        /^[^d]*?$/8 failed to match "abc".
129    16. Added a missing copyright notice to pcrecpp_internal.h.
131    17. Make it more clear in the documentation that values returned from
132        pcre_exec() in ovector are byte offsets, not character counts.
134    18. Tidied a few places to stop certain compilers from issuing warnings.
136    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
137        supplied by Stefan Weber. I made a further small update for 7.8 because
138        there is a change of source arrangements: the pcre_searchfuncs.c module is
139        replaced by pcre_ucd.c.
142    Version 7.7 07-May-08
143    ---------------------
145    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
146        a string to a long long, pretend we don't even have a long long." This is
147        done by checking for the strtoq, strtoll, and _strtoi64 functions.
149    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
150        pre-7.6 versions, which defined a global no_arg variable instead of putting
151        it in the RE class. (See also #8 below.)
153    3.  Remove a line of dead code, identified by coverity and reported by Nuno
154        Lopes.
156    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
158        (1) The include/exclude patterns were being applied to the whole pathnames
159            of files, instead of just to the final components.
161        (2) If there was more than one level of directory, the subdirectories were
162            skipped unless they satisfied the include/exclude conditions. This is
163            inconsistent with GNU grep (and could even be seen as contrary to the
164            pcregrep specification - which I improved to make it absolutely clear).
165            The action now is always to scan all levels of directory, and just
166            apply the include/exclude patterns to regular files.
168    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
169        --exclude_dir in the tests to avoid scanning .svn directories.
171    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
172        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
173        doesn't support NULs in patterns.
175    7.  Added some missing "const"s to declarations of static tables in
176        pcre_compile.c and pcre_dfa_exec.c.
178    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
179        caused by fix #2  above. (Subsequently also a second patch to fix the
180        first patch. And a third patch - this was a messy problem.)
182    9.  Applied Craig's patch to remove the use of push_back().
184    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
185        matching function regexec().
187    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
188        which, however, unlike Perl's \g{...}, are subroutine calls, not back
189        references. PCRE supports relative numbers with this syntax (I don't think
190        Oniguruma does).
192    12. Previously, a group with a zero repeat such as (...){0} was completely
193        omitted from the compiled regex. However, this means that if the group
194        was called as a subroutine from elsewhere in the pattern, things went wrong
195        (an internal error was given). Such groups are now left in the compiled
196        pattern, with a new opcode that causes them to be skipped at execution
197        time.
199    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
200        to the way PCRE behaves:
202        (a) A lone ] character is dis-allowed (Perl treats it as data).
204        (b) A back reference to an unmatched subpattern matches an empty string
205            (Perl fails the current match path).
207        (c) A data ] in a character class must be notated as \] because if the
208            first data character in a class is ], it defines an empty class. (In
209            Perl it is not possible to have an empty class.) The empty class []
210            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
211            The negative empty class [^] matches any one character, independently
212            of the DOTALL setting.
214    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
215        non-existent subpattern following a character class starting with ']' and
216        containing () gave an internal compiling error instead of "reference to
217        non-existent subpattern". Fortunately, when the pattern did exist, the
218        compiled code was correct. (When scanning forwards to check for the
219        existencd of the subpattern, it was treating the data ']' as terminating
220        the class, so got the count wrong. When actually compiling, the reference
221        was subsequently set up correctly.)
223    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
224        it was being rejected as not supported by pcre_dfa_exec(), even though
225        other assertions are supported. I have made pcre_dfa_exec() support
226        (*FAIL).
228    16. The implementation of 13c above involved the invention of a new opcode,
229        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
230        cannot be changed at match time, I realized I could make a small
231        improvement to matching performance by compiling OP_ALLANY instead of
232        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
233        on the OP_ANY path.
235    17. Compiling pcretest on Windows with readline support failed without the
236        following two fixes: (1) Make the unistd.h include conditional on
237        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
239    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
240        ncurses library to be included for pcretest when ReadLine support is
241        requested, but also to allow for it to be overridden. This patch came from
242        Daniel Bergström.
244    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
245        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
246        any errors with the current Unicode tables. Thanks to Peter Kankowski for
247        spotting this.
250    Version 7.6 28-Jan-08
251    ---------------------
253    1.  A character class containing a very large number of characters with
254        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
255        overflow.
257    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
258        HAVE_LONG_LONG is not defined.
260    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
261        bring them up to date and include new features. This patch includes:
263        - Fixed PH's badly added libz and libbz2 support.
264        - Fixed a problem with static linking.
265        - Added pcredemo. [But later removed - see 7 below.]
266        - Fixed dftables problem and added an option.
267        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
268            HAVE_LONG_LONG.
269        - Added readline support for pcretest.
270        - Added an listing of the option settings after cmake has run.
272    4.  A user submitted a patch to Makefile that makes it easy to create
273        "pcre.dll" under mingw when using Configure/Make. I added stuff to
274        Makefile.am that cause it to include this special target, without
275        affecting anything else. Note that the same mingw target plus all
276        the other distribution libraries and programs are now supported
277        when configuring with CMake (see 6 below) instead of with
278        Configure/Make.
280    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
281        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
282        exported in the Windows port". It has not yet been confirmed that the patch
283        solves the problem, but it does no harm.
285    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
286        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
287        with CMake, and also correct the comment about stack recursion.
289    7.  Remove the automatic building of pcredemo from the ./configure system and
290        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
291        of a program that users should build themselves after PCRE is installed, so
292        building it automatically is not really right. What is more, it gave
293        trouble in some build environments.
295    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
298    Version 7.5 10-Jan-08
299    ---------------------
301    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
302        values in parens when parsing an RE using the C++ wrapper."
304    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
305        Characters greater than 255 were excluded from the class instead of being
306        included.
308    3.  The same bug as (2) above applied to negated POSIX classes such as
309        [:^space:].
311    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
312        defined or documented. It seems to have been a typo for PCRE_STATIC, so
313        I have changed it.
315    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
316        first named subpattern) and a construct such as (?&a) would reference the
317        first named subpattern whose name started with "a" (in other words, the
318        length check was missing). Both these problems are fixed. "Subpattern name
319        expected" is now given for (?&) (a zero-length name), and this patch also
320        makes it give the same error for \k'' (previously it complained that that
321        was a reference to a non-existent subpattern).
323    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
324        this is right because (?- can be followed by option settings as well as by
325        digits. I have, however, made the messages clearer.
327    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
328        than the number used in the conditional) now cause a compile-time error.
329        This is actually not compatible with Perl, which accepts such patterns, but
330        treats the conditional as always being FALSE (as PCRE used to), but it
331        seems to me that giving a diagnostic is better.
333    8.  Change "alphameric" to the more common word "alphanumeric" in comments
334        and messages.
336    9.  Fix two occurrences of "backslash" in comments that should have been
337        "backspace".
339    10. Remove two redundant lines of code that can never be obeyed (their function
340        was moved elsewhere).
342    11. The program that makes PCRE's Unicode character property table had a bug
343        which caused it to generate incorrect table entries for sequences of
344        characters that have the same character type, but are in different scripts.
345        It amalgamated them into a single range, with the script of the first of
346        them. In other words, some characters were in the wrong script. There were
347        thirteen such cases, affecting characters in the following ranges:
349          U+002b0 - U+002c1
350          U+0060c - U+0060d
351          U+0061e - U+00612
352          U+0064b - U+0065e
353          U+0074d - U+0076d
354          U+01800 - U+01805
355          U+01d00 - U+01d77
356          U+01d9b - U+01dbf
357          U+0200b - U+0200f
358          U+030fc - U+030fe
359          U+03260 - U+0327f
360          U+0fb46 - U+0fbb1
361          U+10450 - U+1049d
363    12. The -o option (show only the matching part of a line) for pcregrep was not
364        compatible with GNU grep in that, if there was more than one match in a
365        line, it showed only the first of them. It now behaves in the same way as
366        GNU grep.
368    13. If the -o and -v options were combined for pcregrep, it printed a blank
369        line for every non-matching line. GNU grep prints nothing, and pcregrep now
370        does the same. The return code can be used to tell if there were any
371        non-matching lines.
373    14. Added --file-offsets and --line-offsets to pcregrep.
375    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
376        infinitely looping recursion. The bug was that positive lookaheads were not
377        being skipped when checking for a possible empty match (negative lookaheads
378        and both kinds of lookbehind were skipped).
380    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
381        inclusion of <windows.h> to before rather than after the definition of
382        INVALID_FILE_ATTRIBUTES (patch from David Byron).
384    17. Specifying a possessive quantifier with a specific limit for a Unicode
385        character property caused pcre_compile() to compile bad code, which led at
386        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
387        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
388        caused the error; without that there was no problem.
390    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
392    19. Added --enable-pcretest-libreadline.
394    20. In pcrecpp.cc, the variable 'count' was incremented twice in
395        RE::GlobalReplace(). As a result, the number of replacements returned was
396        double what it should be. I removed one of the increments, but Craig sent a
397        later patch that removed the other one (the right fix) and added unit tests
398        that check the return values (which was not done before).
400    21. Several CMake things:
402        (1) Arranged that, when cmake is used on Unix, the libraries end up with
403            the names libpcre and libpcreposix, not just pcre and pcreposix.
405        (2) The above change means that pcretest and pcregrep are now correctly
406            linked with the newly-built libraries, not previously installed ones.
410    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
411        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
412        UTF-8 newline character). The key issue is that the pattern starts .*;
413        this means that the match must be either at the beginning, or after a
414        newline. The bug was in the code for advancing after a failed match and
415        checking that the new position followed a newline. It was not taking
416        account of UTF-8 characters correctly.
418    23. PCRE was behaving differently from Perl in the way it recognized POSIX
419        character classes. PCRE was not treating the sequence [:...:] as a
420        character class unless the ... were all letters. Perl, however, seems to
421        allow any characters between [: and :], though of course it rejects as
422        unknown any "names" that contain non-letters, because all the known class
423        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
424        for example, whereas PCRE did not - it did not recognize a POSIX character
425        class. This seemed a bit dangerous, so the code has been changed to be
426        closer to Perl. The behaviour is not identical to Perl, because PCRE will
427        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
428        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
429        Perl does, and where it didn't before.
431    24. Rewrite so as to remove the single use of %n from pcregrep because in some
432        Windows environments %n is disabled by default.
435    Version 7.4 21-Sep-07
436    ---------------------
438    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
439        means that a class such as [\s] counted as "explicit reference to CR or
440        LF". That isn't really right - the whole point of the change was to try to
441        help when there was an actual mention of one of the two characters. So now
442        the change happens only if \r or \n (or a literal CR or LF) character is
443        encountered.
445    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
446        of both had grown to the point where there were only 3 bits left.
447        Fortunately, there was spare space in the data structure, and so I have
448        moved the internal flags into a new 16-bit field to free up more option
449        bits.
451    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
452        but did not set the internal JCHANGED flag - either of these is enough to
453        control the way the "get" function works - but the PCRE_INFO_JCHANGED
454        facility is supposed to tell if (?J) was ever used, so now (?J) at the
455        start sets both bits.
457    4.  Added options (at build time, compile time, exec time) to change \R from
458        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
460    5.  doc/pcresyntax.html was missing from the distribution.
462    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
463        compatibility, even though it is no longer used.
465    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
466        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
467        windows.h file is present (where different names are used). [This was
468        reversed later after testing - see 16 below.]
470    8.  Changed all #include <config.h> to #include "config.h". There were also
471        some further <pcre.h> cases that I changed to "pcre.h".
473    9.  When pcregrep was used with the --colour option, it missed the line ending
474        sequence off the lines that it output.
476    10. It was pointed out to me that arrays of string pointers cause lots of
477        relocations when a shared library is dynamically loaded. A technique of
478        using a single long string with a table of offsets can drastically reduce
479        these. I have refactored PCRE in four places to do this. The result is
480        dramatic:
482          Originally:                          290
483          After changing UCP table:            187
484          After changing error message table:   43
485          After changing table of "verbs"       36
486          After changing table of Posix names   22
488        Thanks to the folks working on Gregex for glib for this insight.
490    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
491        unicode-properties was also set.
493    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
495    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
496        checked only for CRLF.
498    14. Added casts to pcretest.c to avoid compiler warnings.
500    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
502    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
503        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
504        entirely. This removes changes made in 7 above.
506    17. The CMake files have been updated, and there is now more information about
507        building with CMake in the NON-UNIX-USE document.
510    Version 7.3 28-Aug-07
511    ---------------------
513     1. In the rejigging of the build system that eventually resulted in 7.1, the
514        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
515        brackets there is not right, since it causes compilers to look for an
516        installed pcre.h, not the version that is in the source that is being
517        compiled (which of course may be different). I have changed it back to:
519          #include "pcre.h"
521        I have a vague recollection that the change was concerned with compiling in
522        different directories, but in the new build system, that is taken care of
523        by the VPATH setting the Makefile.
525     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
526        when the subject happened to end in the byte 0x85 (e.g. if the last
527        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
528        characters but of course it shouldn't be taken as a newline when it is part
529        of another character. The bug was that, for an unlimited repeat of . in
530        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
531        characters when looking for a newline.
533     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
535     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
536        in debug output.
538     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
539        long printing in the pcrecpp unittest when running under MinGW.
541     6. ESC_K was left out of the EBCDIC table.
543     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
544        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
545        limit also applies to "virtual nesting" when a pattern is recursive, and in
546        this case 1000 isn't so big. I have been able to remove this limit at the
547        expense of backing off one optimization in certain circumstances. Normally,
548        when pcre_exec() would call its internal match() function recursively and
549        immediately return the result unconditionally, it uses a "tail recursion"
550        feature to save stack. However, when a subpattern that can match an empty
551        string has an unlimited repetition quantifier, it no longer makes this
552        optimization. That gives it a stack frame in which to save the data for
553        checking that an empty string has been matched. Previously this was taken
554        from the 1000-entry workspace that had been reserved. So now there is no
555        explicit limit, but more stack is used.
557     8. Applied Daniel's patches to solve problems with the import/export magic
558        syntax that is required for Windows, and which was going wrong for the
559        pcreposix and pcrecpp parts of the library. These were overlooked when this
560        problem was solved for the main library.
562     9. There were some crude static tests to avoid integer overflow when computing
563        the size of patterns that contain repeated groups with explicit upper
564        limits. As the maximum quantifier is 65535, the maximum group length was
565        set at 30,000 so that the product of these two numbers did not overflow a
566        32-bit integer. However, it turns out that people want to use groups that
567        are longer than 30,000 bytes (though not repeat them that many times).
568        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
569        made it possible to implement the integer overflow checks in a much more
570        dynamic way, which I have now done. The artificial limitation on group
571        length has been removed - we now have only the limit on the total length of
572        the compiled pattern, which depends on the LINK_SIZE setting.
574    10. Fixed a bug in the documentation for get/copy named substring when
575        duplicate names are permitted. If none of the named substrings are set, the
576        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
577        empty string.
579    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
580        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
581        because the ] is interpreted as the first data character and the
582        terminating ] is not found. PCRE has been made compatible with Perl in this
583        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
584        cause memory overwriting.
586    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
587        string has been matched (to stop an infinite loop). It was not recognizing
588        a conditional subpattern that could match an empty string if that
589        subpattern was within another subpattern. For example, it looped when
590        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
591        condition was not nested. This bug has been fixed.
593    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
594        past the start of the subject in the presence of bytes with the top bit
595        set, for example "\x8aBCD".
597    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
598        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
600    14. Optimized (?!) to (*FAIL).
602    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
603        This restricts code points to be within the range 0 to 0x10FFFF, excluding
604        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
605        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
606        does: it's just the validity check that is more restrictive.
608    16. Inserted checks for integer overflows during escape sequence (backslash)
609        processing, and also fixed erroneous offset values for syntax errors during
610        backslash processing.
612    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
613        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
615    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
616        caused an overrun.
618    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
619        something other than just ASCII characters) inside a group that had an
620        unlimited repeat caused a loop at compile time (while checking to see
621        whether the group could match an empty string).
623    20. Debugging a pattern containing \p or \P could cause a crash. For example,
624        [\P{Any}] did so. (Error in the code for printing property names.)
626    21. An orphan \E inside a character class could cause a crash.
628    22. A repeated capturing bracket such as (A)? could cause a wild memory
629        reference during compilation.
631    23. There are several functions in pcre_compile() that scan along a compiled
632        expression for various reasons (e.g. to see if it's fixed length for look
633        behind). There were bugs in these functions when a repeated \p or \P was
634        present in the pattern. These operators have additional parameters compared
635        with \d, etc, and these were not being taken into account when moving along
636        the compiled data. Specifically:
638        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
639            length.
641        (b) An item such as \pL+ within a repeated group could cause crashes or
642            loops.
644        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
645            "reference to non-existent subpattern" error.
647        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
649    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
650        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
652    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
654    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
655        character were causing crashes (broken optimization).
657    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
658        \p or \P) caused a compile-time loop.
660    28. More problems have arisen in unanchored patterns when CRLF is a valid line
661        break. For example, the unstudied pattern [\r\n]A does not match the string
662        "\r\nA" because change 7.0/46 below moves the current point on by two
663        characters after failing to match at the start. However, the pattern \nA
664        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
665        the same is true. There doesn't seem any very clean way out of this, but
666        what I have chosen to do makes the common cases work: PCRE now takes note
667        of whether there can be an explicit match for \r or \n anywhere in the
668        pattern, and if so, 7.0/46 no longer applies. As part of this change,
669        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
670        pattern has explicit CR or LF references.
672    29. Added (*CR) etc for changing newline setting at start of pattern.
675    Version 7.2 19-Jun-07
676    ---------------------
678     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
679        which is apparently normally available under Windows.
681     2. Re-jig the pcregrep tests with different newline settings in an attempt
682        to make them independent of the local environment's newline setting.
684     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
686     4. Some of the "internals" tests were previously cut out when the link size
687        was not 2, because the output contained actual offsets. The recent new
688        "Z" feature of pcretest means that these can be cut out, making the tests
689        usable with all link sizes.
691     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
692        stack recursion. This gives a massive performance boost under BSD, but just
693        a small improvement under Linux. However, it saves one field in the frame
694        in all cases.
696     6. Added more features from the forthcoming Perl 5.10:
698        (a) (?-n) (where n is a string of digits) is a relative subroutine or
699            recursion call. It refers to the nth most recently opened parentheses.
701        (b) (?+n) is also a relative subroutine call; it refers to the nth next
702            to be opened parentheses.
704        (c) Conditions that refer to capturing parentheses can be specified
705            relatively, for example, (?(-2)... or (?(+3)...
707        (d) \K resets the start of the current match so that everything before
708            is not part of it.
710        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
712        (f) \g{name} is another synonym - part of Perl 5.10's unification of
713            reference syntax.
715        (g) (?| introduces a group in which the numbering of parentheses in each
716            alternative starts with the same number.
718        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
720     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
723     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
724        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
725        for detecting groups that can match an empty string.
727     9. A pattern with a very large number of alternatives (more than several
728        hundred) was running out of internal workspace during the pre-compile
729        phase, where pcre_compile() figures out how much memory will be needed. A
730        bit of new cunning has reduced the workspace needed for groups with
731        alternatives. The 1000-alternative test pattern now uses 12 bytes of
732        workspace instead of running out of the 4096 that are available.
734    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
736    11. Applied patch from Google to remove an optimization that didn't quite work.
737        The report of the bug said:
739          pcrecpp::RE("a*").FullMatch("aaa") matches, while
740          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
741          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
743    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
744        it matched the wrong number of bytes.
747    Version 7.1 24-Apr-07
748    ---------------------
750     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
751        that is more "standard", making use of automake and other Autotools. There
752        is some re-arrangement of the files and adjustment of comments consequent
753        on this.
755     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
756        for recursive directory scanning broke on some systems because the files
757        are not scanned in any specific order and on different systems the order
758        was different. A call to "sort" has been inserted into RunGrepTest for the
759        approprate test as a short-term fix. In the longer term there may be an
760        alternative.
762     3. I had an email from Eric Raymond about problems translating some of PCRE's
763        man pages to HTML (despite the fact that I distribute HTML pages, some
764        people do their own conversions for various reasons). The problems
765        concerned the use of low-level troff macros .br and .in. I have therefore
766        removed all such uses from the man pages (some were redundant, some could
767        be replaced by .nf/.fi pairs). The 132html script that I use to generate
768        HTML has been updated to handle .nf/.fi and to complain if it encounters
769        .br or .in.
771     4. Updated comments in configure.ac that get placed in config.h.in and also
772        arranged for config.h to be included in the distribution, with the name
773        config.h.generic, for the benefit of those who have to compile without
774        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
776     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
777        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
778        makevp.bat for the current PCRE, using the additional files
779        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
781     6. A Windows user reported a minor discrepancy with test 2, which turned out
782        to be caused by a trailing space on an input line that had got lost in his
783        copy. The trailing space was an accident, so I've just removed it.
785     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
786        that is needed.
788     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
789        as "const" (a) because they are and (b) because it helps the PHP
790        maintainers who have recently made a script to detect big data structures
791        in the php code that should be moved to the .rodata section. I remembered
792        to update Builducptable as well, so it won't revert if ucptable.h is ever
793        re-created.
795     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
796        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
797        order to be able to cut out the UTF-8 tables in the latter when UTF-8
798        support is not required. This saves 1.5-2K of code, which is important in
799        some applications.
801        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
802        so as not to refer to the tables, even though these functions will never be
803        called when UTF-8 support is disabled. Otherwise there are problems with a
804        shared library.
806    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
808        (a) It was defining its arguments as char * instead of void *.
810        (b) It was assuming that all moves were upwards in memory; this was true
811            a long time ago when I wrote it, but is no longer the case.
813        The emulated memove() is provided for those environments that have neither
814        memmove() nor bcopy(). I didn't think anyone used it these days, but that
815        is clearly not the case, as these two bugs were recently reported.
817    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
818        and Detrail to create the HTML documentation, the .txt form of the man
819        pages, and it removes trailing spaces from listed files. It also creates
820        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
821        case, it wraps all the #defines with #ifndefs. This script should be run
822        before "make dist".
824    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
825        with Unicode property support.
827        (a) For a maximizing quantifier, if the two different cases of the
828            character were of different lengths in their UTF-8 codings (there are
829            some cases like this - I found 11), and the matching function had to
830            back up over a mixture of the two cases, it incorrectly assumed they
831            were both the same length.
833        (b) When PCRE was configured to use the heap rather than the stack for
834            recursion during matching, it was not correctly preserving the data for
835            the other case of a UTF-8 character when checking ahead for a match
836            while processing a minimizing repeat. If the check also involved
837            matching a wide character, but failed, corruption could cause an
838            erroneous result when trying to check for a repeat of the original
839            character.
841    13. Some tidying changes to the testing mechanism:
843        (a) The RunTest script now detects the internal link size and whether there
844            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
845            values substituted by "configure". (The RunGrepTest script already did
846            this for UTF-8.) The configure.ac script no longer substitutes the
847            relevant variables.
849        (b) The debugging options /B and /D in pcretest show the compiled bytecode
850            with length and offset values. This means that the output is different
851            for different internal link sizes. Test 2 is skipped for link sizes
852            other than 2 because of this, bypassing the problem. Unfortunately,
853            there was also a test in test 3 (the locale tests) that used /B and
854            failed for link sizes other than 2. Rather than cut the whole test out,
855            I have added a new /Z option to pcretest that replaces the length and
856            offset values with spaces. This is now used to make test 3 independent
857            of link size. (Test 2 will be tidied up later.)
859    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
860        segmentation fault instead of returning the appropriate error message.
862    15. In multiline mode when the newline sequence was set to "any", the pattern
863        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
864        This doesn't seem right; it now treats the CRLF combination as the line
865        ending, and so does not match in that case. It's only a pattern such as ^$
866        that would hit this one: something like ^ABC$ would have failed after \r
867        and then tried again after \r\n.
869    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
870        in an attempt to make files that differ only in their line terminators
871        compare equal. This works on Linux.
873    17. Under certain error circumstances pcregrep might try to free random memory
874        as it exited. This is now fixed, thanks to valgrind.
876    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
877        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
878        was because its rules for how to advance for /g after matching an empty
879        string at the end of a line did not allow for this case. They now check for
880        it specially.
882    20. pcretest is supposed to handle patterns and data of any length, by
883        extending its buffers when necessary. It was getting this wrong when the
884        buffer for a data line had to be extended.
886    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
887        CRLF as a newline sequence.
889    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
890        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
891        I have nevertheless tidied it up.
893    23. Added some casts to kill warnings from HP-UX ia64 compiler.
895    24. Added a man page for pcre-config.
898    Version 7.0 19-Dec-06
899    ---------------------
901     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
902        moving to gcc 4.1.1.
904     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
905        sys/time.h, which is documented as needed for this function. It doesn't
906        seem to matter on Linux, but it showed up on some releases of OS X.
908     3. It seems that there are systems where bytes whose values are greater than
909        127 match isprint() in the "C" locale. The "C" locale should be the
910        default when a C program starts up. In most systems, only ASCII printing
911        characters match isprint(). This difference caused the output from pcretest
912        to vary, making some of the tests fail. I have changed pcretest so that:
914        (a) When it is outputting text in the compiled version of a pattern, bytes
915            other than 32-126 are always shown as hex escapes.
917        (b) When it is outputting text that is a matched part of a subject string,
918            it does the same, unless a different locale has been set for the match
919            (using the /L modifier). In this case, it uses isprint() to decide.
921     4. Fixed a major bug that caused incorrect computation of the amount of memory
922        required for a compiled pattern when options that changed within the
923        pattern affected the logic of the preliminary scan that determines the
924        length. The relevant options are -x, and -i in UTF-8 mode. The result was
925        that the computed length was too small. The symptoms of this bug were
926        either the PCRE error "internal error: code overflow" from pcre_compile(),
927        or a glibc crash with a message such as "pcretest: free(): invalid next
928        size (fast)". Examples of patterns that provoked this bug (shown in
929        pcretest format) are:
931          /(?-x: )/x
932          /(?x)(?-x: \s*#\s*)/
933          /((?i)[\x{c0}])/8
934          /(?i:[\x{c0}])/8
936        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
937        is now done differently.
939     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
940        wrapper classes; (b) implement a new function in the C++ scanner that is
941        more efficient than the old way of doing things because it avoids levels of
942        recursion in the regex matching; (c) add a paragraph to the documentation
943        for the FullMatch() function.
945     6. The escape sequence \n was being treated as whatever was defined as
946        "newline". Not only was this contrary to the documentation, which states
947        that \n is character 10 (hex 0A), but it also went horribly wrong when
948        "newline" was defined as CRLF. This has been fixed.
950     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
951        was being set to -1 for the "end of line" case (supposedly a value that no
952        character can have). Though this value is never used (the check for end of
953        line is "zero bytes in current character"), it caused compiler complaints.
954        I've changed it to 0xffffffff.
956     8. In pcre_version.c, the version string was being built by a sequence of
957        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
958        string (as it is for production releases) called a macro with an empty
959        argument. The C standard says the result of this is undefined. The gcc
960        compiler treats it as an empty string (which was what was wanted) but it is
961        reported that Visual C gives an error. The source has been hacked around to
962        avoid this problem.
964     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
965        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
966        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
967        of them did).
969    10. Originally, pcretest opened its input and output without "b"; then I was
970        told that "b" was needed in some environments, so it was added for release
971        5.0 to both the input and output. (It makes no difference on Unix-like
972        systems.) Later I was told that it is wrong for the input on Windows. I've
973        now abstracted the modes into two macros, to make it easier to fiddle with
974        them, and removed "b" from the input mode under Windows.
976    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
978    12. Added -help and --help to pcretest as an official way of being reminded
979        of the options.
981    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
982        and pcrecpp.cc because they annoy compilers at high warning levels.
984    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
986    15. Fixed an occurrence of == in configure.ac that should have been = (shell
987        scripts are not C programs :-) and which was not noticed because it works
988        on Linux.
990    16. pcretest is supposed to handle any length of pattern and data line (as one
991        line or as a continued sequence of lines) by extending its input buffer if
992        necessary. This feature was broken for very long pattern lines, leading to
993        a string of junk being passed to pcre_compile() if the pattern was longer
994        than about 50K.
996    17. I have done a major re-factoring of the way pcre_compile() computes the
997        amount of memory needed for a compiled pattern. Previously, there was code
998        that made a preliminary scan of the pattern in order to do this. That was
999        OK when PCRE was new, but as the facilities have expanded, it has become
1000        harder and harder to keep it in step with the real compile phase, and there
1001        have been a number of bugs (see for example, 4 above). I have now found a
1002        cunning way of running the real compile function in a "fake" mode that
1003        enables it to compute how much memory it would need, while actually only
1004        ever using a few hundred bytes of working memory and without too many
1005        tests of the mode. This should make future maintenance and development
1006        easier. A side effect of this work is that the limit of 200 on the nesting
1007        depth of parentheses has been removed (though this was never a serious
1008        limitation, I suspect). However, there is a downside: pcre_compile() now
1009        runs more slowly than before (30% or more, depending on the pattern). I
1010        hope this isn't a big issue. There is no effect on runtime performance.
1012    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1013        newline (only possible for the last line of a file) and it was a
1014        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1016    19. Added additional timing features to pcretest. (1) The -tm option now times
1017        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1018        separate command line item, by a number that specifies the number of
1019        repeats to use when timing. The default is 50000; this gives better
1020        precision, but takes uncomfortably long for very large patterns.
1022    20. Extended pcre_study() to be more clever in cases where a branch of a
1023        subpattern has no definite first character. For example, (a*|b*)[cd] would
1024        previously give no result from pcre_study(). Now it recognizes that the
1025        first character must be a, b, c, or d.
1027    21. There was an incorrect error "recursive call could loop indefinitely" if
1028        a subpattern (or the entire pattern) that was being tested for matching an
1029        empty string contained only one non-empty item after a nested subpattern.
1030        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1031        incorrectly, because the \d was being skipped in the check.
1033    22. The pcretest program now has a new pattern option /B and a command line
1034        option -b, which is equivalent to adding /B to every pattern. This causes
1035        it to show the compiled bytecode, without the additional information that
1036        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1037        is the same as /B/I).
1039    23. A new optimization is now able automatically to treat some sequences such
1040        as a*b as a*+b. More specifically, if something simple (such as a character
1041        or a simple class like \d) has an unlimited quantifier, and is followed by
1042        something that cannot possibly match the quantified thing, the quantifier
1043        is automatically "possessified".
1045    24. A recursive reference to a subpattern whose number was greater than 39
1046        went wrong under certain circumstances in UTF-8 mode. This bug could also
1047        have affected the operation of pcre_study().
1049    25. Realized that a little bit of performance could be had by replacing
1050        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1052    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1054    27. Possessive quantifiers such as a++ were previously implemented by turning
1055        them into atomic groups such as ($>a+). Now they have their own opcodes,
1056        which improves performance. This includes the automatically created ones
1057        from 23 above.
1059    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1060        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1061        the first matched character to be a colon. This applied both to named and
1062        numbered groups.
1064    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1066    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1067        building PCRE on Windows easier, so I have included it in the distribution.
1069    31. There is now a check in pcretest against a ridiculously large number being
1070        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1071        loop, the loop is abandoned.
1073    32. Forward references to subpatterns in conditions such as (?(2)...) where
1074        subpattern 2 is defined later cause pcre_compile() to search forwards in
1075        the pattern for the relevant set of parentheses. This search went wrong
1076        when there were unescaped parentheses in a character class, parentheses
1077        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1079    33. "Subroutine" calls and backreferences were previously restricted to
1080        referencing subpatterns earlier in the regex. This restriction has now
1081        been removed.
1083    34. Added a number of extra features that are going to be in Perl 5.10. On the
1084        whole, these are just syntactic alternatives for features that PCRE had
1085        previously implemented using the Python syntax or my own invention. The
1086        other formats are all retained for compatibility.
1088        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1089            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1090            also .NET compatible.
1092        (b) A recursion or subroutine call to a named group can now be defined as
1093            (?&name) as well as (?P>name).
1095        (c) A backreference to a named group can now be defined as \k<name> or
1096            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1097            5.10, are also .NET compatible.
1099        (d) A conditional reference to a named group can now use the syntax
1100            (?(<name>) or (?('name') as well as (?(name).
1102        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1103            groups (named and numbered) that are never evaluated inline, but can be
1104            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1105            is always false. There may be only one alternative in such a group.
1107        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1108            as the simple (?(R). The condition is true only if the most recent
1109            recursion is that of the given number or name. It does not search out
1110            through the entire recursion stack.
1112        (g) The escape \gN or \g{N} has been added, where N is a positive or
1113            negative number, specifying an absolute or relative reference.
1115    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1116        some "unreachable code" warnings.
1118    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1119        things, this adds five new scripts.
1121    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1122        There were also incompatibilities regarding the handling of \Q..\E inside
1123        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1124        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1126    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1127        matches an empty string, and forcibly breaks the loop. There were bugs in
1128        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1129        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1130        separate and independent bugs (that affected different cases) have been
1131        fixed.
1133    39. Refactored the code to abolish the use of different opcodes for small
1134        capturing bracket numbers. This is a tidy that I avoided doing when I
1135        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1136        The new approach is not only tidier, it makes it possible to reduce the
1137        memory needed to fix the previous bug (38).
1139    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1140        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1141        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1142        mode.
1144    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1145        report.
1147    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1148        copy construction and assignment in the C++ wrapper.
1150    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1151        couple of bugs that could have given wrong results in the "--newline=crlf"
1152        case.
1154    44. Added a number of casts and did some reorganization of signed/unsigned int
1155        variables following suggestions from Dair Grant. Also renamed the variable
1156        "this" as "item" because it is a C++ keyword.
1158    45. Arranged for dftables to add
1160          #include "pcre_internal.h"
1162        to pcre_chartables.c because without it, gcc 4.x may remove the array
1163        definition from the final binary if PCRE is built into a static library and
1164        dead code stripping is activated.
1166    46. For an unanchored pattern, if a match attempt fails at the start of a
1167        newline sequence, and the newline setting is CRLF or ANY, and the next two
1168        characters are CRLF, advance by two characters instead of one.
1171    Version 6.7 04-Jul-06
1172    ---------------------
1174     1. In order to handle tests when input lines are enormously long, pcretest has
1175        been re-factored so that it automatically extends its buffers when
1176        necessary. The code is crude, but this _is_ just a test program. The
1177        default size has been increased from 32K to 50K.
1179     2. The code in pcre_study() was using the value of the re argument before
1180        testing it for NULL. (Of course, in any sensible call of the function, it
1181        won't be NULL.)
1183     3. The memmove() emulation function in pcre_internal.h, which is used on
1184        systems that lack both memmove() and bcopy() - that is, hardly ever -
1185        was missing a "static" storage class specifier.
1187     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1188        containing an extended class (one that cannot be represented by a bitmap
1189        because it contains high-valued characters or Unicode property items, e.g.
1190        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1191        pattern, but PCRE should not loop if you do not (it no longer does).
1192        [Detail: two cases were found: (a) a repeated subpattern containing an
1193        extended class; (b) a recursive reference to a subpattern that followed a
1194        previous extended class. It wasn't skipping over the extended class
1195        correctly when UTF-8 mode was not set.]
1197     5. A negated single-character class was not being recognized as fixed-length
1198        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1199        compile error "lookbehind assertion is not fixed length".
1201     6. The RunPerlTest auxiliary script was showing an unexpected difference
1202        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1203        write a Perl script that can interpret lines of an input file either as
1204        byte characters or as UTF-8, which is what "perltest" was being required to
1205        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1206        can't do is switch easily at run time between having the "use utf8;" pragma
1207        or not. In the end, I fudged it by using the RunPerlTest script to insert
1208        "use utf8;" explicitly for the UTF-8 tests.
1210     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1211        the end of the subject string, contrary to the documentation and to what
1212        Perl does. This was true of both matching functions. Now it matches only at
1213        the start of the subject and immediately after *internal* newlines.
1215     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1216        a pointer to an int instead of a pointer to an unsigned long int. This
1217        caused problems on 64-bit systems.
1219     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1220        instance of the 'standard' template library not being so standard".
1222    10. There was no check on the number of named subpatterns nor the maximum
1223        length of a subpattern name. The product of these values is used to compute
1224        the size of the memory block for a compiled pattern. By supplying a very
1225        long subpattern name and a large number of named subpatterns, the size
1226        computation could be caused to overflow. This is now prevented by limiting
1227        the length of names to 32 characters, and the number of named subpatterns
1228        to 10,000.
1230    11. Subpatterns that are repeated with specific counts have to be replicated in
1231        the compiled pattern. The size of memory for this was computed from the
1232        length of the subpattern and the repeat count. The latter is limited to
1233        65535, but there was no limit on the former, meaning that integer overflow
1234        could in principle occur. The compiled length of a repeated subpattern is
1235        now limited to 30,000 bytes in order to prevent this.
1237    12. Added the optional facility to have named substrings with the same name.
1239    13. Added the ability to use a named substring as a condition, using the
1240        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1241        are numbers (not recommended). Forward references are permitted.
1243    14. Added forward references in named backreferences (if you see what I mean).
1245    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1246        pattern could run off the end of the subject. For example, the pattern
1247        "(?s)(.{1,5})"8 did this with the subject "ab".
1249    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1250        PCRE_CASELESS was set when matching characters that were quantified with ?
1251        or *.
1253    17. A character class other than a single negated character that had a minimum
1254        but no maximum quantifier - for example [ab]{6,} - was not handled
1255        correctly by pce_dfa_exec(). It would match only one character.
1257    18. A valid (though odd) pattern that looked like a POSIX character
1258        class but used an invalid character after [ (for example [[,abc,]]) caused
1259        pcre_compile() to give the error "Failed: internal error: code overflow" or
1260        in some cases to crash with a glibc free() error. This could even happen if
1261        the pattern terminated after [[ but there just happened to be a sequence of
1262        letters, a binary zero, and a closing ] in the memory that followed.
1264    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1265        over the years. Originally (before any Unicode support), just the bottom 8
1266        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1267        output from "man perlunicode" includes this:
1269          The regular expression compiler produces polymorphic opcodes.  That
1270          is, the pattern adapts to the data and automatically switches to
1271          the Unicode character scheme when presented with Unicode data--or
1272          instead uses a traditional byte scheme when presented with byte
1273          data.
1275        Sadly, a wide octal escape does not cause a switch, and in a string with
1276        no other multibyte characters, these octal escapes are treated as before.
1277        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1278        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1279        Unicode string.
1281        I have not perpetrated such confusion in PCRE. Up till now, it took just
1282        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1283        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1284        translate to the appropriate multibyte character.
1286    29. Applied some refactoring to reduce the number of warnings from Microsoft
1287        and Borland compilers. This has included removing the fudge introduced
1288        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1289        a warning about an unused variable.
1291    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1292        characters since release 4.0, because Perl (from release 5.004) does not.
1293        [Or at least, is documented not to: some releases seem to be in conflict
1294        with the documentation.] However, when a pattern was studied with
1295        pcre_study() and all its branches started with \s, PCRE still included VT
1296        as a possible starting character. Of course, this did no harm; it just
1297        caused an unnecessary match attempt.
1299    22. Removed a now-redundant internal flag bit that recorded the fact that case
1300        dependency changed within the pattern. This was once needed for "required
1301        byte" processing, but is no longer used. This recovers a now-scarce options
1302        bit. Also moved the least significant internal flag bit to the most-
1303        significant bit of the word, which was not previously used (hangover from
1304        the days when it was an int rather than a uint) to free up another bit for
1305        the future.
1307    23. Added support for CRLF line endings as well as CR and LF. As well as the
1308        default being selectable at build time, it can now be changed at runtime
1309        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1310        specify that it is scanning data with non-default line endings.
1312    24. Changed the definition of CXXLINK to make it agree with the definition of
1313        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1315    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1316        recursions. This makes a big different to stack usage for some patterns.
1318    26. If a subpattern containing a named recursion or subroutine reference such
1319        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1320        the space required for the compiled pattern went wrong and gave too small a
1321        value. Depending on the environment, this could lead to "Failed: internal
1322        error: code overflow at offset 49" or "glibc detected double free or
1323        corruption" errors.
1325    27. Applied patches from Google (a) to support the new newline modes and (b) to
1326        advance over multibyte UTF-8 characters in GlobalReplace.
1328    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1329        difference for some implementation of PCRE in some Windows version.
1331    29. Added some extra testing facilities to pcretest:
1333        \q<number>   in a data line sets the "match limit" value
1334        \Q<number>   in a data line sets the "match recursion limt" value
1335        -S <number>  sets the stack size, where <number> is in megabytes
1337        The -S option isn't available for Windows.
1340    Version 6.6 06-Feb-06
1341    ---------------------
1343     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1344        in pcreposix.h. I have copied the definition from pcre.h.
1346     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1347        because pcre.h is no longer a built file.
1349     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1350        not normally included in the compiled code.
1353    Version 6.5 01-Feb-06
1354    ---------------------
1356     1. When using the partial match feature with pcre_dfa_exec(), it was not
1357        anchoring the second and subsequent partial matches at the new starting
1358        point. This could lead to incorrect results. For example, with the pattern
1359        /1234/, partially matching against "123" and then "a4" gave a match.
1361     2. Changes to pcregrep:
1363        (a) All non-match returns from pcre_exec() were being treated as failures
1364            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1365            error message is output. Some extra information is given for the
1366            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1367            probably the only errors that are likely to be caused by users (by
1368            specifying a regex that has nested indefinite repeats, for instance).
1369            If there are more than 20 of these errors, pcregrep is abandoned.
1371        (b) A binary zero was treated as data while matching, but terminated the
1372            output line if it was written out. This has been fixed: binary zeroes
1373            are now no different to any other data bytes.
1375        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1376            used to set a locale for matching. The --locale=xxxx long option has
1377            been added (no short equivalent) to specify a locale explicitly on the
1378            pcregrep command, overriding the environment variables.
1380        (d) When -B was used with -n, some line numbers in the output were one less
1381            than they should have been.
1383        (e) Added the -o (--only-matching) option.
1385        (f) If -A or -C was used with -c (count only), some lines of context were
1386            accidentally printed for the final match.
1388        (g) Added the -H (--with-filename) option.
1390        (h) The combination of options -rh failed to suppress file names for files
1391            that were found from directory arguments.
1393        (i) Added the -D (--devices) and -d (--directories) options.
1395        (j) Added the -F (--fixed-strings) option.
1397        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1399        (l) Added the --colo(u)r option.
1401        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1402            is not present by default.
1404     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1405        items such as (?R) or (?1), when the recursion could match a number of
1406        alternatives. If it matched one of the alternatives, but subsequently,
1407        outside the recursion, there was a failure, the code tried to back up into
1408        the recursion. However, because of the way PCRE is implemented, this is not
1409        possible, and the result was an incorrect result from the match.
1411        In order to prevent this happening, the specification of recursion has
1412        been changed so that all such subpatterns are automatically treated as
1413        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1415     4. I had overlooked the fact that, in some locales, there are characters for
1416        which isalpha() is true but neither isupper() nor islower() are true. In
1417        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1418        and ordfeminine) are like this. This affected the treatment of \w and \W
1419        when they appeared in character classes, but not when they appeared outside
1420        a character class. The bit map for "word" characters is now created
1421        separately from the results of isalnum() instead of just taking it from the
1422        upper, lower, and digit maps. (Plus the underscore character, of course.)
1424     5. The above bug also affected the handling of POSIX character classes such as
1425        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1426        permanent tables. Instead, the bit maps for such a class were previously
1427        created as the appropriate unions of the upper, lower, and digit bitmaps.
1428        Now they are created by subtraction from the [[:word:]] class, which has
1429        its own bitmap.
1431     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1432        It is created by subtracting the vertical space characters (\x09, \x0a,
1433        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1434        subtraction was done in the overall bitmap for a character class, meaning
1435        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1436        be recognized. This bug has been fixed.
1438     7. Patches from the folks at Google:
1440          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1441          real life, but is still worth protecting against".
1443          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1444          regular expressions".
1446          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1447          have it.
1449          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1450          "configure" and the latter not, in order to fix a problem somebody had
1451          with compiling the Arg class on HP-UX.
1453          (e) Improve the error-handling of the C++ wrapper a little bit.
1455          (f) New tests for checking recursion limiting.
1457     8. The pcre_memmove() function, which is used only if the environment does not
1458        have a standard memmove() function (and is therefore rarely compiled),
1459        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1460        returning a result (though PCRE never actually uses the result).
1462     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1463        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1464        returned instead of calling malloc() with an overflowing number that would
1465        most likely cause subsequent chaos.
1467    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1469    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1470        with this option is matched, the nmatch and pmatch options of regexec() are
1471        ignored.
1473    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1474        provided in case anyone wants to the the POSIX interface with UTF-8
1475        strings.
1477    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1478        C++ linking (needed for some HP-UX environments).
1480    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1481        (unused parameter) and in the pcre_printint() function (omitted "default"
1482        switch label when the default is to do nothing).
1484    15. Added some code to make it possible, when PCRE is compiled as a C++
1485        library, to replace subject pointers for pcre_exec() with a smart pointer
1486        class, thus making it possible to process discontinuous strings.
1488    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1489        much the same function. They were added by different people who were trying
1490        to make PCRE easy to compile on non-Unix systems. It has been suggested
1491        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1492        for compiling on Windows systems. I have therefore replaced it with
1493        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1494        defaults to "extern" for C or "extern C" for C++, which works fine on
1495        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1496        SCOPE with something explicit in config.h. In addition:
1498        (a) pcreposix.h still had just "extern" instead of either of these macros;
1499            I have replaced it with PCRE_DATA_SCOPE.
1501        (b) Functions such as _pcre_xclass(), which are internal to the library,
1502            but external in the C sense, all had PCRE_EXPORT in their definitions.
1503            This is apparently wrong for the Windows case, so I have removed it.
1504            (It makes no difference on Unix-like systems.)
1506    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1507        of recursive calls to match(). This is different to MATCH_LIMIT because
1508        that limits the total number of calls to match(), not all of which increase
1509        the depth of recursion. Limiting the recursion depth limits the amount of
1510        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1511        when PCRE is compiled, and changed at run time. A patch from Google adds
1512        this functionality to the C++ interface.
1514    18. Changes to the handling of Unicode character properties:
1516        (a) Updated the table to Unicode 4.1.0.
1518        (b) Recognize characters that are not in the table as "Cn" (undefined).
1520        (c) I revised the way the table is implemented to a much improved format
1521            which includes recognition of ranges. It now supports the ranges that
1522            are defined in UnicodeData.txt, and it also amalgamates other
1523            characters into ranges. This has reduced the number of entries in the
1524            table from around 16,000 to around 3,000, thus reducing its size
1525            considerably. I realized I did not need to use a tree structure after
1526            all - a binary chop search is just as efficient. Having reduced the
1527            number of entries, I extended their size from 6 bytes to 8 bytes to
1528            allow for more data.
1530        (d) Added support for Unicode script names via properties such as \p{Han}.
1532    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1533        matching that character.
1535    20. When matching a repeated Unicode property with a minimum greater than zero,
1536        (for example \pL{2,}), PCRE could look past the end of the subject if it
1537        reached it while seeking the minimum number of characters. This could
1538        happen only if some of the characters were more than one byte long, because
1539        there is a check for at least the minimum number of bytes.
1541    21. Refactored the implementation of \p and \P so as to be more general, to
1542        allow for more different types of property in future. This has changed the
1543        compiled form incompatibly. Anybody with saved compiled patterns that use
1544        \p or \P will have to recompile them.
1546    22. Added "Any" and "L&" to the supported property types.
1548    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1549        but give a compile time error if the value is greater than 0xff.
1551    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1552        accidentally not being installed or uninstalled.
1554    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1555        made were to insert the current release number. This seemed silly, because
1556        it made things harder for people building PCRE on systems that don't run
1557        "configure". I have turned pcre.h into a distributed file, no longer built
1558        by "configure", with the version identification directly included. There is
1559        no longer a pcre.h.in file.
1561        However, this change necessitated a change to the pcre-config script as
1562        well. It is built from pcre-config.in, and one of the substitutions was the
1563        release number. I have updated configure.ac so that ./configure now finds
1564        the release number by grepping pcre.h.
1566    26. Added the ability to run the tests under valgrind.
1569    Version 6.4 05-Sep-05
1570    ---------------------
1572     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1573        "--" to be printed when multiple files were scanned, even when none of the
1574        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1575        consider it to be a bug, and have restored the previous behaviour.
1577     2. A couple of code tidies to get rid of compiler warnings.
1579     3. The pcretest program used to cheat by referring to symbols in the library
1580        whose names begin with _pcre_. These are internal symbols that are not
1581        really supposed to be visible externally, and in some environments it is
1582        possible to suppress them. The cheating is now confined to including
1583        certain files from the library's source, which is a bit cleaner.
1585     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1586        file's purpose clearer.
1588     5. Reorganized pcre_ucp_findchar().
1591    Version 6.3 15-Aug-05
1592    ---------------------
1594     1. The file libpcre.pc.in did not have general read permission in the tarball.
1596     2. There were some problems when building without C++ support:
1598        (a) If C++ support was not built, "make install" and "make test" still
1599            tried to test it.
1601        (b) There were problems when the value of CXX was explicitly set. Some
1602            changes have been made to try to fix these, and ...
1604        (c) --disable-cpp can now be used to explicitly disable C++ support.
1606        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1607            backslash in a target when C++ was disabled. This confuses some
1608            versions of "make", apparently. Using an intermediate variable solves
1609            this. (Same for CPP_LOBJ.)
1611     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1612        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1613        necessary on certain architectures.
1615     4. Added a setting of -export-symbols-regex to the link command to remove
1616        those symbols that are exported in the C sense, but actually are local
1617        within the library, and not documented. Their names all begin with
1618        "_pcre_". This is not a perfect job, because (a) we have to except some
1619        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1620        available (and never for static libraries). I have made a note to try to
1621        find a way round (a) in the future.
1624    Version 6.2 01-Aug-05
1625    ---------------------
1627     1. There was no test for integer overflow of quantifier values. A construction
1628        such as {1111111111111111} would give undefined results. What is worse, if
1629        a minimum quantifier for a parenthesized subpattern overflowed and became
1630        negative, the calculation of the memory size went wrong. This could have
1631        led to memory overwriting.
1633     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1635     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1636        operating environments where this matters.
1638     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1639        PCRE options from within the C++ wrapper.
1641     5. Named capturing subpatterns were not being correctly counted when a pattern
1642        was compiled. This caused two problems: (a) If there were more than 100
1643        such subpatterns, the calculation of the memory needed for the whole
1644        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1645        back references of the form \12, where the number was greater than 9, were
1646        not recognized as back references, even though there were sufficient
1647        previous subpatterns.
1649     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1650        versions of gcc, e.g. 2.95.4.
1653    Version 6.1 21-Jun-05
1654    ---------------------
1656     1. There was one reference to the variable "posix" in pcretest.c that was not
1657        surrounded by "#if !defined NOPOSIX".
1659     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1660        the cross-check on the old pcre_info() function, for the benefit of the
1661        cut-down version of PCRE that is currently imported into Exim.
1663     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1664        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1665        patterns that start (?i) but I don't think that matters. The use of (?i) is
1666        just an example; this all applies to the other options as well.
1668     4. Since libtool seems to echo the compile commands it is issuing, the output
1669        from "make" can be reduced a bit by putting "@" in front of each libtool
1670        compile command.
1672     5. Patch from the folks at Google for configure.in to be a bit more thorough
1673        in checking for a suitable C++ installation before trying to compile the
1674        C++ stuff. This should fix a reported problem when a compiler was present,
1675        but no suitable headers.
1677     6. The man pages all had just "PCRE" as their title. I have changed them to
1678        be the relevant file name. I have also arranged that these names are
1679        retained in the file doc/pcre.txt, which is a concatenation in text format
1680        of all the man pages except the little individual ones for each function.
1682     7. The NON-UNIX-USE file had not been updated for the different set of source
1683        files that come with release 6. I also added a few comments about the C++
1684        wrapper.
1687    Version 6.0 07-Jun-05
1688    ---------------------
1690     1. Some minor internal re-organization to help with my DFA experiments.
1692     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1693        didn't matter for the library itself when fully configured, but did matter
1694        when compiling without UCP support, or within Exim, where the ucp files are
1695        not imported.
1697     3. Refactoring of the library code to split up the various functions into
1698        different source modules. The addition of the new DFA matching code (see
1699        below) to a single monolithic source would have made it really too
1700        unwieldy, quite apart from causing all the code to be include in a
1701        statically linked application, when only some functions are used. This is
1702        relevant even without the DFA addition now that patterns can be compiled in
1703        one application and matched in another.
1705        The downside of splitting up is that there have to be some external
1706        functions and data tables that are used internally in different modules of
1707        the library but which are not part of the API. These have all had their
1708        names changed to start with "_pcre_" so that they are unlikely to clash
1709        with other external names.
1711     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1712        a different (DFA) algorithm. Although it is slower than the original
1713        function, it does have some advantages for certain types of matching
1714        problem.
1716     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1717        including restarting after a partial match.
1719     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1720        defined when compiling for Windows was sent to me. I have put it into the
1721        code, though I have no means of testing or verifying it.
1723     7. Added the pcre_refcount() auxiliary function.
1725     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1726        match before or at the first newline in the subject string. In pcretest,
1727        the /f option on a pattern can be used to set this.
1729     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1730        would behave wrongly. This has been present in PCRE since release 4.0.
1732    10. A number of changes to the pcregrep command:
1734        (a) Refactored how -x works; insert ^(...)$ instead of setting
1735            PCRE_ANCHORED and checking the length, in preparation for adding
1736            something similar for -w.
1738        (b) Added the -w (match as a word) option.
1740        (c) Refactored the way lines are read and buffered so as to have more
1741            than one at a time available.
1743        (d) Implemented a pcregrep test script.
1745        (e) Added the -M (multiline match) option. This allows patterns to match
1746            over several lines of the subject. The buffering ensures that at least
1747            8K, or the rest of the document (whichever is the shorter) is available
1748            for matching (and similarly the previous 8K for lookbehind assertions).
1750        (f) Changed the --help output so that it now says
1752              -w, --word-regex(p)
1754            instead of two lines, one with "regex" and the other with "regexp"
1755            because that confused at least one person since the short forms are the
1756            same. (This required a bit of code, as the output is generated
1757            automatically from a table. It wasn't just a text change.)
1759        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1760            option but starts with a hyphen. Could be a pattern or a path name
1761            starting with a hyphen, for instance.
1763        (h) "-" can be given as a file name to represent stdin.
1765        (i) When file names are being printed, "(standard input)" is used for
1766            the standard input, for compatibility with GNU grep. Previously
1767            "<stdin>" was used.
1769        (j) The option --label=xxx can be used to supply a name to be used for
1770            stdin when file names are being printed. There is no short form.
1772        (k) Re-factored the options decoding logic because we are going to add
1773            two more options that take data. Such options can now be given in four
1774            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1776        (l) Added the -A, -B, and -C options for requesting that lines of context
1777            around matches be printed.
1779        (m) Added the -L option to print the names of files that do not contain
1780            any matching lines, that is, the complement of -l.
1782        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1783            continue to scan other files.
1785        (o) The -s option was incorrectly implemented. For compatibility with other
1786            greps, it now suppresses the error message for a non-existent or non-
1787            accessible file (but not the return code). There is a new option called
1788            -q that suppresses the output of matching lines, which was what -s was
1789            previously doing.
1791        (p) Added --include and --exclude options to specify files for inclusion
1792            and exclusion when recursing.
1794    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1795        Hopefully, it now does.
1797    12. Missing cast in pcre_study().
1799    13. Added an "uninstall" target to the makefile.
1801    14. Replaced "extern" in the function prototypes in Makefile.in with
1802        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1803        world, but is set differently for Windows.
1805    15. Added a second compiling function called pcre_compile2(). The only
1806        difference is that it has an extra argument, which is a pointer to an
1807        integer error code. When there is a compile-time failure, this is set
1808        non-zero, in addition to the error test pointer being set to point to an
1809        error message. The new argument may be NULL if no error number is required
1810        (but then you may as well call pcre_compile(), which is now just a
1811        wrapper). This facility is provided because some applications need a
1812        numeric error indication, but it has also enabled me to tidy up the way
1813        compile-time errors are handled in the POSIX wrapper.
1815    16. Added VPATH=.libs to the makefile; this should help when building with one
1816        prefix path and installing with another. (Or so I'm told by someone who
1817        knows more about this stuff than I do.)
1819    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1820        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1821        match everything, including newlines. This is not POSIX-compatible, but
1822        somebody wanted the feature. From pcretest it can be activated by using
1823        both the P and the s flags.
1825    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1827    19. libpcre.pc was being incorrectly installed as executable.
1829    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1830        it now also looks for '\r' so that it will work unmodified on Windows.
1832    21. Added Google's contributed C++ wrapper to the distribution.
1834    22. Added some untidy missing memory free() calls in pcretest, to keep
1835        Electric Fence happy when testing.
1839    Version 5.0 13-Sep-04
1840    ---------------------
1842     1. Internal change: literal characters are no longer packed up into items
1843        containing multiple characters in a single byte-string. Each character
1844        is now matched using a separate opcode. However, there may be more than one
1845        byte in the character in UTF-8 mode.
1847     2. The pcre_callout_block structure has two new fields: pattern_position and
1848        next_item_length. These contain the offset in the pattern to the next match
1849        item, and its length, respectively.
1851     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1852        insertion of callouts before each pattern item. Added the /C option to
1853        pcretest to make use of this.
1855     4. On the advice of a Windows user, the lines
1857          #if defined(_WIN32) || defined(WIN32)
1858          _setmode( _fileno( stdout ), 0x8000 );
1859          #endif  /* defined(_WIN32) || defined(WIN32) */
1861        have been added to the source of pcretest. This apparently does useful
1862        magic in relation to line terminators.
1864     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1865        for the benefit of those environments where the "b" makes a difference.
1867     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1868        to know about it. I have put a hack into configure.in that adds in code
1869        to set GCC=yes if CC=icc. This seems to end up at a point in the
1870        generated configure script that is early enough to affect the setting of
1871        compiler options, which is what is needed, but I have no means of testing
1872        whether it really works. (The user who reported this had patched the
1873        generated configure script, which of course I cannot do.)
1875        LATER: After change 22 below (new libtool files), the configure script
1876        seems to know about icc (and also ecc). Therefore, I have commented out
1877        this hack in configure.in.
1879     7. Added support for pkg-config (2 patches were sent in).
1881     8. Negated POSIX character classes that used a combination of internal tables
1882        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1883        [[:^ascii]]. Typically, they would match almost any characters. The other
1884        POSIX classes were not broken in this way.
1886     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1887        to find the match, as PCRE was deluded into thinking that the match had to
1888        start at the start point or following a newline. The same bug applied to
1889        patterns with negative forward assertions or any backward assertions
1890        preceding ".*" at the start, unless the pattern required a fixed first
1891        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1893    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1894        starting at the last subject character, bytes beyond the end of the subject
1895        string were read.
1897    11. Renamed the variable "class" as "classbits" to make life easier for C++
1898        users. (Previously there was a macro definition, but it apparently wasn't
1899        enough.)
1901    12. Added the new field "tables" to the extra data so that tables can be passed
1902        in at exec time, or the internal tables can be re-selected. This allows
1903        a compiled regex to be saved and re-used at a later time by a different
1904        program that might have everything at different addresses.
1906    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1907        -R library as well as a -L library.
1909    14. The debugging options of pcretest (-d on the command line or D on a
1910        pattern) showed incorrect output for anything following an extended class
1911        that contained multibyte characters and which was followed by a quantifier.
1913    15. Added optional support for general category Unicode character properties
1914        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1915        support. It adds about 90K to the size of the library. The meanings of the
1916        inbuilt class escapes such as \d and \s have NOT been changed.
1918    16. Updated pcredemo.c to include calls to free() to release the memory for the
1919        compiled pattern.
1921    17. The generated file chartables.c was being created in the source directory
1922        instead of in the building directory. This caused the build to fail if the
1923        source directory was different from the building directory, and was
1924        read-only.
1926    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1927        file. No doubt somebody will tell me if they don't make sense... Also added
1928        Dan Mooney's comments about building on OpenVMS.
1930    19. Added support for partial matching via the PCRE_PARTIAL option for
1931        pcre_exec() and the \P data escape in pcretest.
1933    20. Extended pcretest with 3 new pattern features:
1935        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1936              write the compiled pattern to the file whose name is "rest-of-line".
1937              This is a straight binary dump of the data, with the saved pointer to
1938              the character tables forced to be NULL. The study data, if any, is
1939              written too. After writing, pcretest reads a new pattern.
1941        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1942              compiled pattern from the given file. There must not be any
1943              occurrences of "<" in the file name (pretty unlikely); if there are,
1944              pcretest will instead treat the initial "<" as a pattern delimiter.
1945              After reading in the pattern, pcretest goes on to read data lines as
1946              usual.
1948        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1949              and 16-bit fields in a compiled pattern, to simulate a pattern that
1950              was compiled on a host of opposite endianness.
1952    21. The pcre-exec() function can now cope with patterns that were compiled on
1953        hosts of opposite endianness, with this restriction:
1955          As for any compiled expression that is saved and used later, the tables
1956          pointer field cannot be preserved; the extra_data field in the arguments
1957          to pcre_exec() should be used to pass in a tables address if a value
1958          other than the default internal tables were used at compile time.
1960    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1961        now diagnosed as an error. Previously, most of the time, a negative number
1962        would have been treated as zero, but if in addition "ovector" was passed as
1963        NULL, a crash could occur.
1965    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1966        new versions from the libtool 1.5 distribution (the last one is a copy of
1967        a file called libtool.m4). This seems to have fixed the need to patch
1968        "configure" to support Darwin 1.3 (which I used to do). However, I still
1969        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1970        workstation).
1972    24. Changed the PCRE licence to be the more standard "BSD" licence.
1975    Version 4.5 01-Dec-03
1976    ---------------------
1978     1. There has been some re-arrangement of the code for the match() function so
1979        that it can be compiled in a version that does not call itself recursively.
1980        Instead, it keeps those local variables that need separate instances for
1981        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1982        needs to "recurse". Keeping track of where control must go is done by means
1983        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1984        hide most of the details from the main code, and operates only if
1985        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1986        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1987        operating.
1989        To make it easier for callers to provide specially tailored get/free
1990        functions for this usage, two new functions, pcre_stack_malloc, and
1991        pcre_stack_free, are used. They are always called in strict stacking order,
1992        and the size of block requested is always the same.
1994        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1995        PCRE has been compiled to use the stack or the heap for recursion. The
1996        -C option of pcretest uses this to show which version is compiled.
1998        A new data escape \S, is added to pcretest; it causes the amounts of store
1999        obtained and freed by both kinds of malloc/free at match time to be added
2000        to the output.
2002     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2003        what's available on my current Linux desktop machine.
2005     3. When matching a UTF-8 string, the test for a valid string at the start has
2006        been extended. If start_offset is not zero, PCRE now checks that it points
2007        to a byte that is the start of a UTF-8 character. If not, it returns
2008        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2009        this is necessary because there may be backward assertions in the pattern.
2010        When matching the same subject several times, it may save resources to use
2011        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2013     4. The code for checking the validity of UTF-8 strings has been tightened so
2014        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2015        containing "overlong sequences".
2017     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2018        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2019        should have been "&", but it just so happened that all the cases this let
2020        through by mistake were picked up later in the function.
2022     6. I had used a variable called "isblank" - this is a C99 function, causing
2023        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2025     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2026        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2027        so the version is shown; (c) stop "make test" echoing "./RunTest".
2029     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2031     9. The prototype for memmove() for systems that don't have it was using
2032        size_t, but the inclusion of the header that defines size_t was later. I've
2033        moved the #includes for the C headers earlier to avoid this.
2035    10. Added some adjustments to the code to make it easier to compiler on certain
2036        special systems:
2038          (a) Some "const" qualifiers were missing.
2039          (b) Added the macro EXPORT before all exported functions; by default this
2040              is defined to be empty.
2041          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2042              that it reads its output file name as an argument instead of writing
2043              to the standard output and assuming this can be redirected.
2045    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2046        class containing characters with values greater than 255, PCRE compilation
2047        went into a loop.
2049    12. A recursive reference to a subpattern that was within another subpattern
2050        that had a minimum quantifier of zero caused PCRE to crash. For example,
2051        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2052        recursion. If the recursively-called subpattern itself had a zero repeat,
2053        that was OK.
2055    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2056        buffer into which it was copied (for escape processing) was still set at
2057        1024, so long lines caused crashes.
2059    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2060        "internal error: code overflow...". This applied to any character class
2061        that was followed by a possessive quantifier.
2063    15. Modified the Makefile to add libpcre.la as a prerequisite for
2064        libpcreposix.la because I was told this is needed for a parallel build to
2065        work.
2067    16. If a pattern that contained .* following optional items at the start was
2068        studied, the wrong optimizing data was generated, leading to matching
2069        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2070        matching string must start with a or b or c. The correct conclusion for
2071        this pattern is that a match can start with any character.
2074    Version 4.4 13-Aug-03
2075    ---------------------
2077     1. In UTF-8 mode, a character class containing characters with values between
2078        127 and 255 was not handled correctly if the compiled pattern was studied.
2079        In fixing this, I have also improved the studying algorithm for such
2080        classes (slightly).
2082     2. Three internal functions had redundant arguments passed to them. Removal
2083        might give a very teeny performance improvement.
2085     3. Documentation bug: the value of the capture_top field in a callout is *one
2086        more than* the number of the hightest numbered captured substring.
2088     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2089        in incorrectly linking with a previously installed version. They now link
2090        explicitly with libpcre.la.
2092     5. configure.in no longer needs to recognize Cygwin specially.
2094     6. A problem in pcre.in for Windows platforms is fixed.
2096     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2097        pcretest, it used to include the size of the study block as part of its
2098        output. Unfortunately, the structure contains a field that has a different
2099        size on different hardware architectures. This meant that the tests that
2100        showed this size failed. As the block is currently always of a fixed size,
2101        this information isn't actually particularly useful in pcretest output, so
2102        I have just removed it.
2104     8. Three pre-processor statements accidentally did not start in column 1.
2105        Sadly, there are *still* compilers around that complain, even though
2106        standard C has not required this for well over a decade. Sigh.
2108     9. In pcretest, the code for checking callouts passed small integers in the
2109        callout_data field, which is a void * field. However, some picky compilers
2110        complained about the casts involved for this on 64-bit systems. Now
2111        pcretest passes the address of the small integer instead, which should get
2112        rid of the warnings.
2114    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2115        both compile and run time, and gives an error if an invalid UTF-8 sequence
2116        is found. There is a option for disabling this check in cases where the
2117        string is known to be correct and/or the maximum performance is wanted.
2119    11. In response to a bug report, I changed one line in Makefile.in from
2121            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2122        to
2123            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2125        to look similar to other lines, but I have no way of telling whether this
2126        is the right thing to do, as I do not use Windows. No doubt I'll get told
2127        if it's wrong...
2130    Version 4.3 21-May-03
2131    ---------------------
2133    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2134       Makefile.
2136    2. Some refactoring to improve the quality of the code:
2138       (i)   The utf8_table... variables are now declared "const".
2140       (ii)  The code for \cx, which used the "case flipping" table to upper case
2141             lower case letters, now just substracts 32. This is ASCII-specific,
2142             but the whole concept of \cx is ASCII-specific, so it seems
2143             reasonable.
2145       (iii) PCRE was using its character types table to recognize decimal and
2146             hexadecimal digits in the pattern. This is silly, because it handles
2147             only 0-9, a-f, and A-F, but the character types table is locale-
2148             specific, which means strange things might happen. A private
2149             table is now used for this - though it costs 256 bytes, a table is
2150             much faster than multiple explicit tests. Of course, the standard
2151             character types table is still used for matching digits in subject
2152             strings against \d.
2154       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2155             ending in _t are). So I've renamed it as ESC_tee.
2157    3. The first argument for regexec() in the POSIX wrapper should have been
2158       defined as "const".
2160    4. Changed pcretest to use malloc() for its buffers so that they can be
2161       Electric Fenced for debugging.
2163    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2164       to read one or more bytes before the start of the subject string. Often this
2165       had no effect on PCRE's behaviour, but in some circumstances it could
2166       provoke a segmentation fault.
2168    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2169       to try to read one or more bytes before the start of the subject string.
2171    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2172       UTF-8 support could misbehave in various ways if the subject string
2173       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2174       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2175       back over UTF-8 characters.)
2178    Version 4.2 14-Apr-03
2179    ---------------------
2181    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2183    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2184         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2185         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2186         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2187         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2188           and BUILD_EXEEXT
2189         Note: automatic setting of the BUILD variables is not yet working
2190         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2191           compile-time but not at link-time
2192         [LINK]: use for linking executables only
2193         make different versions for Windows and non-Windows
2194         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2195           libraries
2196         [LINK_FOR_BUILD]: new variable
2197         [OBJEXT]: use throughout
2198         [EXEEXT]: use throughout
2199         <winshared>: new target
2200         <wininstall>: new target
2201         <dftables.o>: use native compiler
2202         <dftables>: use native linker
2203         <install>: handle Windows platform correctly
2204         <clean>: ditto
2205         <check>: ditto
2206         copy DLL to top builddir before testing
2208       As part of these changes, -no-undefined was removed again. This was reported
2209       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2210       in any case.
2212    3. Some tidies to get rid of compiler warnings:
2214       . In the match_data structure, match_limit was an unsigned long int, whereas
2215         match_call_count was an int. I've made them both unsigned long ints.
2217       . In pcretest the fact that a const uschar * doesn't automatically cast to
2218         a void * provoked a warning.
2220       . Turning on some more compiler warnings threw up some "shadow" variables
2221         and a few more missing casts.
2223    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2224       option, a class that contained a single character with a value between 128
2225       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2227    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2228       option, a class that contained several characters, but with at least one
2229       whose value was between 128 and 255 caused PCRE to crash.
2232    Version 4.1 12-Mar-03
2233    ---------------------
2235    1. Compiling with gcc -pedantic found a couple of places where casts were
2236    needed, and a string in dftables.c that was longer than standard compilers are
2237    required to support.
2239    2. Compiling with Sun's compiler found a few more places where the code could
2240    be tidied up in order to avoid warnings.
2242    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2243    first of these names is deprecated in the latest Autoconf in favour of the name
2244    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2245    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2246    analogy I have changed it to CFLAGS_FOR_BUILD.
2248    4. Added -no-undefined to the linking command in the Makefile, because this is
2249    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2250    linking step for the pcreposix library.
2252    5. PCRE was failing to diagnose the case of two named groups with the same
2253    name.
2255    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2256    literal character that is needed in the subject for a match, and scans along to
2257    ensure that it is present before embarking on the full matching process. This
2258    saves time in cases of nested unlimited repeats that are never going to match.
2259    Problem: the scan can take a lot of time if the subject is very long (e.g.
2260    megabytes), thus penalizing straightforward matches. It is now done only if the
2261    amount of subject to be scanned is less than 1000 bytes.
2263    7. A lesser problem with the same optimization is that it was recording the
2264    first character of an anchored pattern as "needed", thus provoking a search
2265    right along the subject, even when the first match of the pattern was going to
2266    fail. The "needed" character is now not set for anchored patterns, unless it
2267    follows something in the pattern that is of non-fixed length. Thus, it still
2268    fulfils its original purpose of finding quick non-matches in cases of nested
2269    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2272    Version 4.0 17-Feb-03
2273    ---------------------
2275    1. If a comment in an extended regex that started immediately after a meta-item
2276    extended to the end of string, PCRE compiled incorrect data. This could lead to
2277    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2279    2. Moved to autoconf 2.53 and libtool 1.4.2.
2281    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2282    the special perltest8 script is no longer needed - all the tests can be run
2283    from a single perltest script.
2285    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2286    by \s. It has now been removed in PCRE. This means it isn't recognized as
2287    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2288    class [:space:] *does* include VT, thereby creating a mess.
2290    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2291    space and tab.
2293    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2294    its new features into the main test script, reducing the number of scripts.
2296    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2297    were backward compatible, and made the (?i) apply to the whole pattern, as if
2298    /i were given. Now it behaves more logically, and applies the option setting
2299    only to what follows. PCRE has been changed to follow suit. However, if it
2300    finds options settings right at the start of the pattern, it extracts them into
2301    the global options, as before. Thus, they show up in the info data.
2303    8. Added support for the \Q...\E escape sequence. Characters in between are
2304    treated as literals. This is slightly different from Perl in that $ and @ are
2305    also handled as literals inside the quotes. In Perl, they will cause variable
2306    interpolation. Note the following examples:
2308        Pattern            PCRE matches      Perl matches
2310        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2311        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2312        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2314    For compatibility with Perl, \Q...\E sequences are recognized inside character
2315    classes as well as outside them.
2317    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2318    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2319    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2320    signed/unsigned warnings.
2322    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2323    option for pcretest, so I've replaced it by a simple function that does just
2324    that job.
2326    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2327    "pcregrep -".
2329    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2330    Java package. This provides some syntactic sugar for simple cases of what my
2331    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2332    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2333    item, you can use this simplified notation. Note that only makes sense with
2334    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2335    greediness, whatever the setting of the PCRE_UNGREEDY option.
2337    13. A change of greediness default within a pattern was not taking effect at
2338    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2339    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2340    was abstracted outside.
2342    14. PCRE now supports the \G assertion. It is true when the current matching
2343    position is at the start point of the match. This differs from \A when the
2344    starting offset is non-zero. Used with the /g option of pcretest (or similar
2345    code), it works in the same way as it does for Perl's /g option. If all
2346    alternatives of a regex begin with \G, the expression is anchored to the start
2347    match position, and the "anchored" flag is set in the compiled expression.
2349    15. Some bugs concerning the handling of certain option changes within patterns
2350    have been fixed. These applied to options other than (?ims). For example,
2351    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2352    been the other way round. Some of this was related to change 7 above.
2354    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2355    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2356    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2357    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2359    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2360    mode. Unlike ".", it always matches newline, whatever the setting of
2361    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2362    assertions. Perl allows it, but it doesn't (in general) work because it can't
2363    calculate the length of the lookbehind. At least, that's the case for Perl
2364    5.8.0 - I've been told they are going to document that it doesn't work in
2365    future.
2367    18. Added an error diagnosis for escapes that PCRE does not support: these are
2368    \L, \l, \N, \P, \p, \U, \u, and \X.
2370    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2371    reading past the end of the pattern in cases such as /[abcd/.
2373    20. PCRE was getting more memory than necessary for patterns with classes that
2374    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2376    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2377    compiling PCRE for use with Virtual Pascal.
2379    22. Small fix to the Makefile to make it work properly if the build is done
2380    outside the source tree.
2382    23. Added a new extension: a condition to go with recursion. If a conditional
2383    subpattern starts with (?(R) the "true" branch is used if recursion has
2384    happened, whereas the "false" branch is used only at the top level.
2386    24. When there was a very long string of literal characters (over 255 bytes
2387    without UTF support, over 250 bytes with UTF support), the computation of how
2388    much memory was required could be incorrect, leading to segfaults or other
2389    strange effects.
2391    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2392    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2393    there was a subsequent back reference to those brackets. This meant that, for
2394    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2395    possible to check for precisely this case. All we can do is abandon the
2396    optimization if .* occurs inside capturing brackets when there are any back
2397    references whatsoever. (See below for a better fix that came later.)
2399    26. The handling of the optimization for finding the first character of a
2400    non-anchored pattern, and for finding a character that is required later in the
2401    match were failing in some cases. This didn't break the matching; it just
2402    failed to optimize when it could. The way this is done has been re-implemented.
2404    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2406    28. Added a new feature that provides some of the functionality that Perl
2407    provides with (?{...}). The facility is termed a "callout". The way it is done
2408    in PCRE is for the caller to provide an optional function, by setting
2409    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2410    global variable. By default it is unset, which disables all calling out. To get
2411    the function called, the regex must include (?C) at appropriate points. This
2412    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2413    This provides a means of identifying different callout points. When PCRE
2414    reaches such a point in the regex, if pcre_callout has been set, the external
2415    function is called. It is provided with data in a structure called
2416    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2417    matching continues; if it returns a non-zero value, the match at the current
2418    point fails. However, backtracking will occur if possible. [This was changed
2419    later and other features added - see item 49 below.]
2421    29. pcretest is upgraded to test the callout functionality. It provides a
2422    callout function that displays information. By default, it shows the start of
2423    the match and the current position in the text. There are some new data escapes
2424    to vary what happens:
2426        \C+         in addition, show current contents of captured substrings
2427        \C-         do not supply a callout function
2428        \C!n        return 1 when callout number n is reached
2429        \C!n!m      return 1 when callout number n is reached for the mth time
2431    30. If pcregrep was called with the -l option and just a single file name, it
2432    output "<stdin>" if a match was found, instead of the file name.
2434    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2435    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2436    pcre_exec(). This saves a malloc/free per call. The default value of
2437    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2438    when configuring.
2440    32. The default maximum size of a compiled pattern is 64K. There have been a
2441    few cases of people hitting this limit. The code now uses macros to handle the
2442    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2443    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2444    configuring. Tests 2 and 5 work only with 2-byte links because they output
2445    debugging information about compiled patterns.
2447    33. Internal code re-arrangements:
2449    (a) Moved the debugging function for printing out a compiled regex into
2450        its own source file (printint.c) and used #include to pull it into
2451        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2452        separate copies.
2454    (b) Defined the list of op-code names for debugging as a macro in
2455        internal.h so that it is next to the definition of the opcodes.
2457    (c) Defined a table of op-code lengths for simpler skipping along compiled
2458        code. This is again a macro in internal.h so that it is next to the
2459        definition of the opcodes.
2461    34. Added support for recursive calls to individual subpatterns, along the
2462    lines of Robin Houston's patch (but implemented somewhat differently).
2464    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2465    allow it to read and process whole directories in Win32. This code was
2466    contributed by Lionel Fourquaux; it has not been tested by me.
2468    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2469    used to name a group. Names consist of alphanumerics and underscores, and must
2470    be unique. Back references use the syntax (?P=name) and recursive calls use
2471    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2472    numbers. The function pcre_fullinfo() can be used after compilation to extract
2473    a name/number map. There are three relevant calls:
2475      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2476      PCRE_INFO_NAMECOUNT            yields the number of entries
2477      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2479    The map is a vector of fixed-size entries. The size of each entry depends on
2480    the length of the longest name used. The first two bytes of each entry are the
2481    group number, most significant byte first. There follows the corresponding
2482    name, zero terminated. The names are in alphabetical order.
2484    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2485    case instead of 255. Making it the same both with and without UTF-8 support
2486    means that the same test output works with both.
2488    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2489    calling malloc() with a zero argument.
2491    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2492    optimization. I've improved things by keeping a bitmap of backreferences with
2493    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2494    fact referenced, the optimization can be applied. It is unlikely that a
2495    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2496    the match to follow \n) will appear inside brackets with a number greater than
2497    31, but if it does, any back reference > 31 suppresses the optimization.
2499    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2500    of disabling numbered capturing parentheses. Any opening parenthesis that is
2501    not followed by ? behaves as if it were followed by ?: but named parentheses
2502    can still be used for capturing (and they will acquire numbers in the usual
2503    way).
2505    41. Redesigned the return codes from the match() function into yes/no/error so
2506    that errors can be passed back from deep inside the nested calls. A malloc
2507    failure while inside a recursive subpattern call now causes the
2508    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2510    42. It is now possible to set a limit on the number of times the match()
2511    function is called in a call to pcre_exec(). This facility makes it possible to
2512    limit the amount of recursion and backtracking, though not in a directly
2513    obvious way, because the match() function is used in a number of different
2514    circumstances. The count starts from zero for each position in the subject
2515    string (for non-anchored patterns). The default limit is, for compatibility, a
2516    large number, namely 10 000 000. You can change this in two ways:
2518    (a) When configuring PCRE before making, you can use --with-match-limit=n
2519        to set a default value for the compiled library.
2521    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2522        a different value is set. See 45 below.
2524    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2526    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2527    of things that can be changed at compile time. The first argument specifies
2528    what is wanted and the second points to where the information is to be placed.
2529    The current list of available information is:
2531      PCRE_CONFIG_UTF8
2533    The output is an integer that is set to one if UTF-8 support is available;
2534    otherwise it is set to zero.
2538    The output is an integer that it set to the value of the code that is used for
2539    newline. It is either LF (10) or CR (13).
2543    The output is an integer that contains the number of bytes used for internal
2544    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2548    The output is an integer that contains the threshold above which the POSIX
2549    interface uses malloc() for output vectors. See item 31 above.
2553    The output is an unsigned integer that contains the default limit of the number
2554    of match() calls in a pcre_exec() execution. See 42 above.
2556    44. pcretest has been upgraded by the addition of the -C option. This causes it
2557    to extract all the available output from the new pcre_config() function, and to
2558    output it. The program then exits immediately.
2560    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2561    order to support additional features. One way would have been to define
2562    pcre_exec2() (for example) with extra arguments, but this would not have been
2563    extensible, and would also have required all calls to the original function to
2564    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2565    is used for passing in "extra" data from pcre_study().
2567    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2568    contains the following fields:
2570      flags         a bitmap indicating which of the following fields are set
2571      study_data    opaque data from pcre_study()
2572      match_limit   a way of specifying a limit on match() calls for a specific
2573                      call to pcre_exec()
2574      callout_data  data for callouts (see 49 below)
2576    The flag bits are also defined in pcre.h, and are
2582    The pcre_study() function now returns one of these new pcre_extra blocks, with
2583    the actual study data pointed to by the study_data field, and the
2584    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2585    before. That is, this change is entirely upwards-compatible and requires no
2586    change to existing code.
2588    If you want to pass in additional data to pcre_exec(), you can either place it
2589    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2590    block.
2592    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2593    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2594    times with different match limits, until it finds the minimum value needed for
2595    pcre_exec() to complete. The value is then output. This can be instructive; for
2596    most simple matches the number is quite small, but for pathological cases it
2597    gets very large very quickly.
2599    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2600    returns the size of the data block pointed to by the study_data field in a
2601    pcre_extra block, that is, the value that was passed as the argument to
2602    pcre_malloc() when PCRE was getting memory in which to place the information
2603    created by pcre_study(). The fourth argument should point to a size_t variable.
2604    pcretest has been extended so that this information is shown after a successful
2605    pcre_study() call when information about the compiled regex is being displayed.
2607    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2608    because what follows is always an absolute path. (Later: it turns out that this
2609    is more than cosmetic for MinGW, because it doesn't like empty path
2610    components.)
2612    49. Some changes have been made to the callout feature (see 28 above):
2614    (i)  A callout function now has three choices for what it returns:
2616           0  =>  success, carry on matching
2617         > 0  =>  failure at this point, but backtrack if possible
2618         < 0  =>  serious error, return this value from pcre_exec()
2620         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2621         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2622         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2623         use by callout functions. It will never be used by PCRE itself.
2625    (ii) The pcre_extra structure (see 45 above) has a void * field called
2626         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2627         pcre_callout_block structure has a field of the same name. The contents of
2628         the field passed in the pcre_extra structure are passed to the callout
2629         function in the corresponding field in the callout block. This makes it
2630         easier to use the same callout-containing regex from multiple threads. For
2631         testing, the pcretest program has a new data escape
2633           \C*n        pass the number n (may be negative) as callout_data
2635         If the callout function in pcretest receives a non-zero value as
2636         callout_data, it returns that value.
2638    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2639    there were some redundant $(CFLAGS) in commands that are now specified as
2640    $(LINK), which already includes $(CFLAGS).
2642    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2643    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2644    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2645    one-byte characters throughout. Note that case-insensitive matching applies
2646    only to characters whose values are less than 256. PCRE doesn't support the
2647    notion of cases for higher-valued characters.
2649    (i)   A character class whose characters are all within 0-255 is handled as
2650          a bit map, and the map is inverted for negative classes. Previously, a
2651          character > 255 always failed to match such a class; however it should
2652          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2654    (ii)  A negated character class with a single character < 255 is coded as
2655          "not this character" (OP_NOT). This wasn't working properly when the test
2656          character was multibyte, either singly or repeated.
2658    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2659          mode, for example: \x{100}{2,3}.
2661    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2662          singly or repeated) now correctly test multibyte characters. However,
2663          PCRE doesn't recognize any characters with values greater than 255 as
2664          digits, spaces, or word characters. Such characters always match \D, \S,
2665          and \W, and never match \d, \s, or \w.
2667    (v)   Classes may now contain characters and character ranges with values
2668          greater than 255. For example: [ab\x{100}-\x{400}].
2670    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2671          PCRE in UTF-8 mode.
2673    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2674    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2675    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2676    value.)
2678    53. The single man page has become too large. I have therefore split it up into
2679    a number of separate man pages. These also give rise to individual HTML pages;
2680    these are now put in a separate directory, and there is an index.html page that
2681    lists them all. Some hyperlinking between the pages has been installed.
2683    54. Added convenience functions for handling named capturing parentheses.
2685    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2686    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2687    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2688    are faulted.
2690    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2691    calling configure. These values are used when compiling the dftables.c program
2692    which is run to generate the source of the default character tables. They
2693    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2694    you will need to set these values.
2696    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2699    Version 3.9 02-Jan-02
2700    ---------------------
2702    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2704    2. If --disable-static was given, the building process failed when trying to
2705    build pcretest and pcregrep. (For some reason it was using libtool to compile
2706    them, which is not right, as they aren't part of the library.)
2709    Version 3.8 18-Dec-01
2710    ---------------------
2712    1. The experimental UTF-8 code was completely screwed up. It was packing the
2713    bytes in the wrong order. How dumb can you get?
2716    Version 3.7 29-Oct-01
2717    ---------------------
2719    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2720    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2721    this didn't happen under Solaris 8, where I normally test things.
2723    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2724    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2725    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2726    this fix an hour or so after the initial 3.7 release.)
2729    Version 3.6 23-Oct-01
2730    ---------------------
2732    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2733    offsets passed as NULL with zero offset count.
2735    2. The config.guess and config.sub files had not been updated when I moved to
2736    the latest autoconf.
2739    Version 3.5 15-Aug-01
2740    ---------------------
2742    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2743    had been forgotten.
2745    2. By using declared but undefined structures, we can avoid using "void"
2746    definitions in pcre.h while keeping the internal definitions of the structures
2747    private.
2749    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2750    user point of view, this means that both static and shared libraries are built
2751    by default, but this can be individually controlled. More of the work of
2752    handling this static/shared cases is now inside libtool instead of PCRE's make
2753    file.
2755    4. The pcretest utility is now installed along with pcregrep because it is
2756    useful for users (to test regexs) and by doing this, it automatically gets
2757    relinked by libtool. The documentation has been turned into a man page, so
2758    there are now .1, .txt, and .html versions in /doc.
2760    5. Upgrades to pcregrep:
2761       (i)   Added long-form option names like gnu grep.
2762       (ii)  Added --help to list all options with an explanatory phrase.
2763       (iii) Added -r, --recursive to recurse into sub-directories.
2764       (iv)  Added -f, --file to read patterns from a file.
2766    6. pcre_exec() was referring to its "code" argument before testing that
2767    argument for NULL (and giving an error if it was NULL).
2769    7. Upgraded Makefile.in to allow for compiling in a different directory from
2770    the source directory.
2772    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2773    options bits, the pointer it was passed was to an int instead of to an unsigned
2774    long int. This mattered only on 64-bit systems.
2776    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2777    generated) instead of pcre.in, which it its source. Also made the same change
2778    in several of the .c files.
2780    10. A new release of gcc defines printf() as a macro, which broke pcretest
2781    because it had an ifdef in the middle of a string argument for printf(). Fixed
2782    by using separate calls to printf().
2784    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2785    script, to force use of CR or LF instead of \n in the source. On non-Unix
2786    systems, the value can be set in config.h.
2788    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2789    absolute limit. Changed the text of the error message to make this clear, and
2790    likewise updated the man page.
2792    13. The limit of 99 on the number of capturing subpatterns has been removed.
2793    The new limit is 65535, which I hope will not be a "real" limit.
2796    Version 3.4 22-Aug-00
2797    ---------------------
2799    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2801    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2804    Version 3.3 01-Aug-00
2805    ---------------------
2807    1. If an octal character was given, but the value was greater than \377, it
2808    was not getting masked to the least significant bits, as documented. This could
2809    lead to crashes in some systems.
2811    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2812    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2814    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2815    These just pass their arguments on to (pcre_free)(), but they are provided
2816    because some uses of PCRE bind it to non-C systems that can call its functions,
2817    but cannot call free() or pcre_free() directly.
2819    4. Add "make test" as a synonym for "make check". Corrected some comments in
2820    the Makefile.
2822    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2823    Makefile.
2825    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2826    command called pgrep for grepping around the active processes.
2828    7. Added the beginnings of support for UTF-8 character strings.
2830    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2831    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2832    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2833    out for the ar command.)
2836    Version 3.2 12-May-00
2837    ---------------------
2839    This is purely a bug fixing release.
2841    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2842    of ZA. This was just one example of several cases that could provoke this bug,
2843    which was introduced by change 9 of version 2.00. The code for breaking
2844    infinite loops after an iteration that matches an empty string was't working
2845    correctly.
2847    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2848    when matched against abbab (for example). After matching an empty string, it
2849    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2850    caused it to match further down the string than it should.
2852    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2853    was there because it doesn't seem to be needed, and it causes trouble on some
2854    systems, as it is not a Standard C header. It has been removed.
2856    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2857    were reported on the Macintosh. The changes were from
2859      while ((c = *(++ptr)) != 0 && c != '\n');
2860    to
2861      while ((c = *(++ptr)) != 0 && c != '\n') ;
2863    Totally extraordinary, but if that's what it takes...
2865    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2866    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2867    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2868    assumes the way PCRE uses memmove() (always moving upwards).
2870    6. PCRE is being used in one environment where strchr() is not available. There
2871    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2872    faster code anyway.
2875    Version 3.1 09-Feb-00
2876    ---------------------
2878    The only change in this release is the fixing of some bugs in Makefile.in for
2879    the "install" target:
2881    (1) It was failing to install pcreposix.h.
2883    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2886    Version 3.0 01-Feb-00
2887    ---------------------
2889    1. Add support for the /+ modifier to perltest (to output $` like it does in
2890    pcretest).
2892    2. Add support for the /g modifier to perltest.
2894    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2895    matches null strings.
2897    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2898    pattern. Perl treats empty patterns specially - it reuses the most recent
2899    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2900    effect.
2902    5. The POSIX interface was broken in that it was just handing over the POSIX
2903    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2904    required a bigger vector, with some working space on the end. This means that
2905    the POSIX wrapper now has to get and free some memory, and copy the results.
2907    6. Added some simple autoconf support, placing the test data and the
2908    documentation in separate directories, re-organizing some of the
2909    information files, and making it build pcre-config (a GNU standard). Also added
2910    libtool support for building PCRE as a shared library, which is now the
2911    default.
2913    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2914    09 are not valid octal constants. Single digits will be used for minor values
2915    less than 10.
2917    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2918    existing programs that set these in the POSIX interface can use PCRE without
2919    modification.
2921    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2922    return all that pcre_info() returns, plus additional data. The pcre_info()
2923    function is retained for compatibility, but is considered to be obsolete.
2925    10. Added experimental recursion feature (?R) to handle one common case that
2926    Perl 5.6 will be able to do with (?p{...}).
2928    11. Added support for POSIX character classes like [:alpha:], which Perl is
2929    adopting.
2932    Version 2.08 31-Aug-99
2933    ----------------------
2935    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2936    trying to match at the startoffset position, but instead was moving forward to
2937    the next newline as if a previous match had failed.
2939    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2940    and could get into a loop if a null string was matched other than at the start
2941    of the subject.
2943    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2944    be distinguished at compile time, and for completeness also added PCRE_DATE.
2946    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2947    in GnuWin32 environments.
2950    Version 2.07 29-Jul-99
2951    ----------------------
2953    1. The documentation is now supplied in plain text form and HTML as well as in
2954    the form of man page sources.
2956    2. C++ compilers don't like assigning (void *) values to other pointer types.
2957    In particular this affects malloc(). Although there is no problem in Standard
2958    C, I've put in casts to keep C++ compilers happy.
2960    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2961    should be (const char *).
2963    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2964    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2965    However, I haven't made this a standard facility. The documentation doesn't
2966    mention it, and the Makefile doesn't support it.
2968    5. The Makefile now contains an "install" target, with editable destinations at
2969    the top of the file. The pcretest program is not installed.
2971    6. pgrep -V now gives the PCRE version number and date.
2973    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2974    causing the entire string to be ignored, instead of just the last character.
2976    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2977    non-matching string, it can take a very, very long time, even for strings of
2978    quite modest length, because of the nested recursion. PCRE now does better in
2979    some of these cases. It does this by remembering the last required literal
2980    character in the pattern, and pre-searching the subject to ensure it is present
2981    before running the real match. In other words, it applies a heuristic to detect
2982    some types of certain failure quickly, and in the above example, if presented
2983    with a string that has no trailing " it gives "no match" very quickly.
2985    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2986    other alternatives are tried instead.
2989    Version 2.06 09-Jun-99
2990    ----------------------
2992    1. Change pcretest's output for amount of store used to show just the code
2993    space, because the remainder (the data block) varies in size between 32-bit and
2994    64-bit systems.
2996    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2997    start matching at. This allows lookbehinds to work when searching for multiple
2998    occurrences in a string.
3000    3. Added additional options to pcretest for testing multiple occurrences:
3002       /+   outputs the rest of the string that follows a match
3003       /g   loops for multiple occurrences, using the new startoffset argument
3004       /G   loops for multiple occurrences by passing an incremented pointer
3006    4. PCRE wasn't doing the "first character" optimization for patterns starting
3007    with \b or \B, though it was doing it for other lookbehind assertions. That is,
3008    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3009    the letter 'x'. On long subject strings, this gives a significant speed-up.
3012  Version 2.05 21-Apr-99  Version 2.05 21-Apr-99
3013  ----------------------  ----------------------

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