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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 whose
46        condition was an assertion, PCRE could crash during matching, both with
47        pcre_exec() and pcre_dfa_exec().
49    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
50        used for matching.
52    11. Unicode property support in character classes was not working for
53        characters (bytes) greater than 127 when not in UTF-8 mode.
55    12. Added the -M command line option to pcretest.
57    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
59    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
61    16. Added comments and documentation about mis-use of no_arg in the C++
62        wrapper.
64    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
65        from Martin Jerabek that uses macro names for all relevant character and
66        string constants.
68    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
69        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
70        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
71        these, but not everybody uses configure.
73    19. A conditional group that had only one branch was not being correctly
74        recognized as an item that could match an empty string. This meant that an
75        enclosing group might also not be so recognized, causing infinite looping
76        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
77        with the subject "ab", where knowledge that the repeated group can match
78        nothing is needed in order to break the loop.
80    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
81        exec(), but without supplying a callout function, matching went wrong.
84    Version 7.8 05-Sep-08
85    ---------------------
87    1.  Replaced UCP searching code with optimized version as implemented for Ad
88        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
89        stage table and inline lookup instead of a function, giving speed ups of 2
90        to 5 times on some simple patterns that I tested. Permission was given to
91        distribute the MultiStage2.py script that generates the tables (it's not in
92        the tarball, but is in the Subversion repository).
94    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
95        scripts.
97    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
98        a group with a zero qualifier. The result of the study could be incorrect,
99        or the function might crash, depending on the pattern.
101    4.  Caseless matching was not working for non-ASCII characters in back
102        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
103        It now works when Unicode Property Support is available.
105    5.  In pcretest, an escape such as \x{de} in the data was always generating
106        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
107        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
108        truncation.
110    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
112    7.  Added two (int) casts to pcregrep when printing the difference of two
113        pointers, in case they are 64-bit values.
115    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
116        test 2 if it fails.
118    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
119        and a #define of that name to empty if it is not externally set. This is to
120        allow users of MSVC to set it if necessary.
122    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
123        the convenience functions in the pcre_get.c source file.
125    11. An option change at the start of a pattern that had top-level alternatives
126        could cause overwriting and/or a crash. This command provoked a crash in
127        some environments:
129          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
131        This potential security problem was recorded as CVE-2008-2371.
133    12. For a pattern where the match had to start at the beginning or immediately
134        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
135        pcre_dfa_exec() could read past the end of the passed subject if there was
136        no match. To help with detecting such bugs (e.g. with valgrind), I modified
137        pcretest so that it places the subject at the end of its malloc-ed buffer.
139    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
140        exec() might read past the end of the data buffer in UTF-8 mode.
142    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
143        the data contained the byte 0x85 as part of a UTF-8 character within its
144        first line. This applied both to normal and DFA matching.
146    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
147        /^[^d]*?$/8 failed to match "abc".
149    16. Added a missing copyright notice to pcrecpp_internal.h.
151    17. Make it more clear in the documentation that values returned from
152        pcre_exec() in ovector are byte offsets, not character counts.
154    18. Tidied a few places to stop certain compilers from issuing warnings.
156    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
157        supplied by Stefan Weber. I made a further small update for 7.8 because
158        there is a change of source arrangements: the pcre_searchfuncs.c module is
159        replaced by pcre_ucd.c.
162    Version 7.7 07-May-08
163    ---------------------
165    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
166        a string to a long long, pretend we don't even have a long long." This is
167        done by checking for the strtoq, strtoll, and _strtoi64 functions.
169    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
170        pre-7.6 versions, which defined a global no_arg variable instead of putting
171        it in the RE class. (See also #8 below.)
173    3.  Remove a line of dead code, identified by coverity and reported by Nuno
174        Lopes.
176    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
178        (1) The include/exclude patterns were being applied to the whole pathnames
179            of files, instead of just to the final components.
181        (2) If there was more than one level of directory, the subdirectories were
182            skipped unless they satisfied the include/exclude conditions. This is
183            inconsistent with GNU grep (and could even be seen as contrary to the
184            pcregrep specification - which I improved to make it absolutely clear).
185            The action now is always to scan all levels of directory, and just
186            apply the include/exclude patterns to regular files.
188    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
189        --exclude_dir in the tests to avoid scanning .svn directories.
191    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
192        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
193        doesn't support NULs in patterns.
195    7.  Added some missing "const"s to declarations of static tables in
196        pcre_compile.c and pcre_dfa_exec.c.
198    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
199        caused by fix #2  above. (Subsequently also a second patch to fix the
200        first patch. And a third patch - this was a messy problem.)
202    9.  Applied Craig's patch to remove the use of push_back().
204    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
205        matching function regexec().
207    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
208        which, however, unlike Perl's \g{...}, are subroutine calls, not back
209        references. PCRE supports relative numbers with this syntax (I don't think
210        Oniguruma does).
212    12. Previously, a group with a zero repeat such as (...){0} was completely
213        omitted from the compiled regex. However, this means that if the group
214        was called as a subroutine from elsewhere in the pattern, things went wrong
215        (an internal error was given). Such groups are now left in the compiled
216        pattern, with a new opcode that causes them to be skipped at execution
217        time.
219    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
220        to the way PCRE behaves:
222        (a) A lone ] character is dis-allowed (Perl treats it as data).
224        (b) A back reference to an unmatched subpattern matches an empty string
225            (Perl fails the current match path).
227        (c) A data ] in a character class must be notated as \] because if the
228            first data character in a class is ], it defines an empty class. (In
229            Perl it is not possible to have an empty class.) The empty class []
230            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
231            The negative empty class [^] matches any one character, independently
232            of the DOTALL setting.
234    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
235        non-existent subpattern following a character class starting with ']' and
236        containing () gave an internal compiling error instead of "reference to
237        non-existent subpattern". Fortunately, when the pattern did exist, the
238        compiled code was correct. (When scanning forwards to check for the
239        existencd of the subpattern, it was treating the data ']' as terminating
240        the class, so got the count wrong. When actually compiling, the reference
241        was subsequently set up correctly.)
243    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
244        it was being rejected as not supported by pcre_dfa_exec(), even though
245        other assertions are supported. I have made pcre_dfa_exec() support
246        (*FAIL).
248    16. The implementation of 13c above involved the invention of a new opcode,
249        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
250        cannot be changed at match time, I realized I could make a small
251        improvement to matching performance by compiling OP_ALLANY instead of
252        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
253        on the OP_ANY path.
255    17. Compiling pcretest on Windows with readline support failed without the
256        following two fixes: (1) Make the unistd.h include conditional on
257        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
259    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
260        ncurses library to be included for pcretest when ReadLine support is
261        requested, but also to allow for it to be overridden. This patch came from
262        Daniel Bergström.
264    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
265        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
266        any errors with the current Unicode tables. Thanks to Peter Kankowski for
267        spotting this.
270    Version 7.6 28-Jan-08
271    ---------------------
273    1.  A character class containing a very large number of characters with
274        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
275        overflow.
277    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
278        HAVE_LONG_LONG is not defined.
280    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
281        bring them up to date and include new features. This patch includes:
283        - Fixed PH's badly added libz and libbz2 support.
284        - Fixed a problem with static linking.
285        - Added pcredemo. [But later removed - see 7 below.]
286        - Fixed dftables problem and added an option.
287        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
288            HAVE_LONG_LONG.
289        - Added readline support for pcretest.
290        - Added an listing of the option settings after cmake has run.
292    4.  A user submitted a patch to Makefile that makes it easy to create
293        "pcre.dll" under mingw when using Configure/Make. I added stuff to
294        Makefile.am that cause it to include this special target, without
295        affecting anything else. Note that the same mingw target plus all
296        the other distribution libraries and programs are now supported
297        when configuring with CMake (see 6 below) instead of with
298        Configure/Make.
300    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
301        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
302        exported in the Windows port". It has not yet been confirmed that the patch
303        solves the problem, but it does no harm.
305    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
306        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
307        with CMake, and also correct the comment about stack recursion.
309    7.  Remove the automatic building of pcredemo from the ./configure system and
310        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
311        of a program that users should build themselves after PCRE is installed, so
312        building it automatically is not really right. What is more, it gave
313        trouble in some build environments.
315    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
318    Version 7.5 10-Jan-08
319    ---------------------
321    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
322        values in parens when parsing an RE using the C++ wrapper."
324    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
325        Characters greater than 255 were excluded from the class instead of being
326        included.
328    3.  The same bug as (2) above applied to negated POSIX classes such as
329        [:^space:].
331    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
332        defined or documented. It seems to have been a typo for PCRE_STATIC, so
333        I have changed it.
335    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
336        first named subpattern) and a construct such as (?&a) would reference the
337        first named subpattern whose name started with "a" (in other words, the
338        length check was missing). Both these problems are fixed. "Subpattern name
339        expected" is now given for (?&) (a zero-length name), and this patch also
340        makes it give the same error for \k'' (previously it complained that that
341        was a reference to a non-existent subpattern).
343    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
344        this is right because (?- can be followed by option settings as well as by
345        digits. I have, however, made the messages clearer.
347    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
348        than the number used in the conditional) now cause a compile-time error.
349        This is actually not compatible with Perl, which accepts such patterns, but
350        treats the conditional as always being FALSE (as PCRE used to), but it
351        seems to me that giving a diagnostic is better.
353    8.  Change "alphameric" to the more common word "alphanumeric" in comments
354        and messages.
356    9.  Fix two occurrences of "backslash" in comments that should have been
357        "backspace".
359    10. Remove two redundant lines of code that can never be obeyed (their function
360        was moved elsewhere).
362    11. The program that makes PCRE's Unicode character property table had a bug
363        which caused it to generate incorrect table entries for sequences of
364        characters that have the same character type, but are in different scripts.
365        It amalgamated them into a single range, with the script of the first of
366        them. In other words, some characters were in the wrong script. There were
367        thirteen such cases, affecting characters in the following ranges:
369          U+002b0 - U+002c1
370          U+0060c - U+0060d
371          U+0061e - U+00612
372          U+0064b - U+0065e
373          U+0074d - U+0076d
374          U+01800 - U+01805
375          U+01d00 - U+01d77
376          U+01d9b - U+01dbf
377          U+0200b - U+0200f
378          U+030fc - U+030fe
379          U+03260 - U+0327f
380          U+0fb46 - U+0fbb1
381          U+10450 - U+1049d
383    12. The -o option (show only the matching part of a line) for pcregrep was not
384        compatible with GNU grep in that, if there was more than one match in a
385        line, it showed only the first of them. It now behaves in the same way as
386        GNU grep.
388    13. If the -o and -v options were combined for pcregrep, it printed a blank
389        line for every non-matching line. GNU grep prints nothing, and pcregrep now
390        does the same. The return code can be used to tell if there were any
391        non-matching lines.
393    14. Added --file-offsets and --line-offsets to pcregrep.
395    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
396        infinitely looping recursion. The bug was that positive lookaheads were not
397        being skipped when checking for a possible empty match (negative lookaheads
398        and both kinds of lookbehind were skipped).
400    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
401        inclusion of <windows.h> to before rather than after the definition of
402        INVALID_FILE_ATTRIBUTES (patch from David Byron).
404    17. Specifying a possessive quantifier with a specific limit for a Unicode
405        character property caused pcre_compile() to compile bad code, which led at
406        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
407        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
408        caused the error; without that there was no problem.
410    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
412    19. Added --enable-pcretest-libreadline.
414    20. In pcrecpp.cc, the variable 'count' was incremented twice in
415        RE::GlobalReplace(). As a result, the number of replacements returned was
416        double what it should be. I removed one of the increments, but Craig sent a
417        later patch that removed the other one (the right fix) and added unit tests
418        that check the return values (which was not done before).
420    21. Several CMake things:
422        (1) Arranged that, when cmake is used on Unix, the libraries end up with
423            the names libpcre and libpcreposix, not just pcre and pcreposix.
425        (2) The above change means that pcretest and pcregrep are now correctly
426            linked with the newly-built libraries, not previously installed ones.
430    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
431        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
432        UTF-8 newline character). The key issue is that the pattern starts .*;
433        this means that the match must be either at the beginning, or after a
434        newline. The bug was in the code for advancing after a failed match and
435        checking that the new position followed a newline. It was not taking
436        account of UTF-8 characters correctly.
438    23. PCRE was behaving differently from Perl in the way it recognized POSIX
439        character classes. PCRE was not treating the sequence [:...:] as a
440        character class unless the ... were all letters. Perl, however, seems to
441        allow any characters between [: and :], though of course it rejects as
442        unknown any "names" that contain non-letters, because all the known class
443        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
444        for example, whereas PCRE did not - it did not recognize a POSIX character
445        class. This seemed a bit dangerous, so the code has been changed to be
446        closer to Perl. The behaviour is not identical to Perl, because PCRE will
447        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
448        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
449        Perl does, and where it didn't before.
451    24. Rewrite so as to remove the single use of %n from pcregrep because in some
452        Windows environments %n is disabled by default.
455    Version 7.4 21-Sep-07
456    ---------------------
458    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
459        means that a class such as [\s] counted as "explicit reference to CR or
460        LF". That isn't really right - the whole point of the change was to try to
461        help when there was an actual mention of one of the two characters. So now
462        the change happens only if \r or \n (or a literal CR or LF) character is
463        encountered.
465    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
466        of both had grown to the point where there were only 3 bits left.
467        Fortunately, there was spare space in the data structure, and so I have
468        moved the internal flags into a new 16-bit field to free up more option
469        bits.
471    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
472        but did not set the internal JCHANGED flag - either of these is enough to
473        control the way the "get" function works - but the PCRE_INFO_JCHANGED
474        facility is supposed to tell if (?J) was ever used, so now (?J) at the
475        start sets both bits.
477    4.  Added options (at build time, compile time, exec time) to change \R from
478        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
480    5.  doc/pcresyntax.html was missing from the distribution.
482    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
483        compatibility, even though it is no longer used.
485    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
486        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
487        windows.h file is present (where different names are used). [This was
488        reversed later after testing - see 16 below.]
490    8.  Changed all #include <config.h> to #include "config.h". There were also
491        some further <pcre.h> cases that I changed to "pcre.h".
493    9.  When pcregrep was used with the --colour option, it missed the line ending
494        sequence off the lines that it output.
496    10. It was pointed out to me that arrays of string pointers cause lots of
497        relocations when a shared library is dynamically loaded. A technique of
498        using a single long string with a table of offsets can drastically reduce
499        these. I have refactored PCRE in four places to do this. The result is
500        dramatic:
502          Originally:                          290
503          After changing UCP table:            187
504          After changing error message table:   43
505          After changing table of "verbs"       36
506          After changing table of Posix names   22
508        Thanks to the folks working on Gregex for glib for this insight.
510    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
511        unicode-properties was also set.
513    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
515    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
516        checked only for CRLF.
518    14. Added casts to pcretest.c to avoid compiler warnings.
520    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
522    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
523        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
524        entirely. This removes changes made in 7 above.
526    17. The CMake files have been updated, and there is now more information about
527        building with CMake in the NON-UNIX-USE document.
530    Version 7.3 28-Aug-07
531    ---------------------
533     1. In the rejigging of the build system that eventually resulted in 7.1, the
534        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
535        brackets there is not right, since it causes compilers to look for an
536        installed pcre.h, not the version that is in the source that is being
537        compiled (which of course may be different). I have changed it back to:
539          #include "pcre.h"
541        I have a vague recollection that the change was concerned with compiling in
542        different directories, but in the new build system, that is taken care of
543        by the VPATH setting the Makefile.
545     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
546        when the subject happened to end in the byte 0x85 (e.g. if the last
547        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
548        characters but of course it shouldn't be taken as a newline when it is part
549        of another character. The bug was that, for an unlimited repeat of . in
550        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
551        characters when looking for a newline.
553     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
555     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
556        in debug output.
558     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
559        long printing in the pcrecpp unittest when running under MinGW.
561     6. ESC_K was left out of the EBCDIC table.
563     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
564        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
565        limit also applies to "virtual nesting" when a pattern is recursive, and in
566        this case 1000 isn't so big. I have been able to remove this limit at the
567        expense of backing off one optimization in certain circumstances. Normally,
568        when pcre_exec() would call its internal match() function recursively and
569        immediately return the result unconditionally, it uses a "tail recursion"
570        feature to save stack. However, when a subpattern that can match an empty
571        string has an unlimited repetition quantifier, it no longer makes this
572        optimization. That gives it a stack frame in which to save the data for
573        checking that an empty string has been matched. Previously this was taken
574        from the 1000-entry workspace that had been reserved. So now there is no
575        explicit limit, but more stack is used.
577     8. Applied Daniel's patches to solve problems with the import/export magic
578        syntax that is required for Windows, and which was going wrong for the
579        pcreposix and pcrecpp parts of the library. These were overlooked when this
580        problem was solved for the main library.
582     9. There were some crude static tests to avoid integer overflow when computing
583        the size of patterns that contain repeated groups with explicit upper
584        limits. As the maximum quantifier is 65535, the maximum group length was
585        set at 30,000 so that the product of these two numbers did not overflow a
586        32-bit integer. However, it turns out that people want to use groups that
587        are longer than 30,000 bytes (though not repeat them that many times).
588        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
589        made it possible to implement the integer overflow checks in a much more
590        dynamic way, which I have now done. The artificial limitation on group
591        length has been removed - we now have only the limit on the total length of
592        the compiled pattern, which depends on the LINK_SIZE setting.
594    10. Fixed a bug in the documentation for get/copy named substring when
595        duplicate names are permitted. If none of the named substrings are set, the
596        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
597        empty string.
599    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
600        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
601        because the ] is interpreted as the first data character and the
602        terminating ] is not found. PCRE has been made compatible with Perl in this
603        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
604        cause memory overwriting.
606    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
607        string has been matched (to stop an infinite loop). It was not recognizing
608        a conditional subpattern that could match an empty string if that
609        subpattern was within another subpattern. For example, it looped when
610        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
611        condition was not nested. This bug has been fixed.
613    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
614        past the start of the subject in the presence of bytes with the top bit
615        set, for example "\x8aBCD".
617    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
618        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
620    14. Optimized (?!) to (*FAIL).
622    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
623        This restricts code points to be within the range 0 to 0x10FFFF, excluding
624        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
625        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
626        does: it's just the validity check that is more restrictive.
628    16. Inserted checks for integer overflows during escape sequence (backslash)
629        processing, and also fixed erroneous offset values for syntax errors during
630        backslash processing.
632    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
633        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
635    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
636        caused an overrun.
638    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
639        something other than just ASCII characters) inside a group that had an
640        unlimited repeat caused a loop at compile time (while checking to see
641        whether the group could match an empty string).
643    20. Debugging a pattern containing \p or \P could cause a crash. For example,
644        [\P{Any}] did so. (Error in the code for printing property names.)
646    21. An orphan \E inside a character class could cause a crash.
648    22. A repeated capturing bracket such as (A)? could cause a wild memory
649        reference during compilation.
651    23. There are several functions in pcre_compile() that scan along a compiled
652        expression for various reasons (e.g. to see if it's fixed length for look
653        behind). There were bugs in these functions when a repeated \p or \P was
654        present in the pattern. These operators have additional parameters compared
655        with \d, etc, and these were not being taken into account when moving along
656        the compiled data. Specifically:
658        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
659            length.
661        (b) An item such as \pL+ within a repeated group could cause crashes or
662            loops.
664        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
665            "reference to non-existent subpattern" error.
667        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
669    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
670        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
672    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
674    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
675        character were causing crashes (broken optimization).
677    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
678        \p or \P) caused a compile-time loop.
680    28. More problems have arisen in unanchored patterns when CRLF is a valid line
681        break. For example, the unstudied pattern [\r\n]A does not match the string
682        "\r\nA" because change 7.0/46 below moves the current point on by two
683        characters after failing to match at the start. However, the pattern \nA
684        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
685        the same is true. There doesn't seem any very clean way out of this, but
686        what I have chosen to do makes the common cases work: PCRE now takes note
687        of whether there can be an explicit match for \r or \n anywhere in the
688        pattern, and if so, 7.0/46 no longer applies. As part of this change,
689        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
690        pattern has explicit CR or LF references.
692    29. Added (*CR) etc for changing newline setting at start of pattern.
695    Version 7.2 19-Jun-07
696    ---------------------
698     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
699        which is apparently normally available under Windows.
701     2. Re-jig the pcregrep tests with different newline settings in an attempt
702        to make them independent of the local environment's newline setting.
704     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
706     4. Some of the "internals" tests were previously cut out when the link size
707        was not 2, because the output contained actual offsets. The recent new
708        "Z" feature of pcretest means that these can be cut out, making the tests
709        usable with all link sizes.
711     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
712        stack recursion. This gives a massive performance boost under BSD, but just
713        a small improvement under Linux. However, it saves one field in the frame
714        in all cases.
716     6. Added more features from the forthcoming Perl 5.10:
718        (a) (?-n) (where n is a string of digits) is a relative subroutine or
719            recursion call. It refers to the nth most recently opened parentheses.
721        (b) (?+n) is also a relative subroutine call; it refers to the nth next
722            to be opened parentheses.
724        (c) Conditions that refer to capturing parentheses can be specified
725            relatively, for example, (?(-2)... or (?(+3)...
727        (d) \K resets the start of the current match so that everything before
728            is not part of it.
730        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
732        (f) \g{name} is another synonym - part of Perl 5.10's unification of
733            reference syntax.
735        (g) (?| introduces a group in which the numbering of parentheses in each
736            alternative starts with the same number.
738        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
740     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
743     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
744        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
745        for detecting groups that can match an empty string.
747     9. A pattern with a very large number of alternatives (more than several
748        hundred) was running out of internal workspace during the pre-compile
749        phase, where pcre_compile() figures out how much memory will be needed. A
750        bit of new cunning has reduced the workspace needed for groups with
751        alternatives. The 1000-alternative test pattern now uses 12 bytes of
752        workspace instead of running out of the 4096 that are available.
754    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
756    11. Applied patch from Google to remove an optimization that didn't quite work.
757        The report of the bug said:
759          pcrecpp::RE("a*").FullMatch("aaa") matches, while
760          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
761          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
763    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
764        it matched the wrong number of bytes.
767    Version 7.1 24-Apr-07
768    ---------------------
770     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
771        that is more "standard", making use of automake and other Autotools. There
772        is some re-arrangement of the files and adjustment of comments consequent
773        on this.
775     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
776        for recursive directory scanning broke on some systems because the files
777        are not scanned in any specific order and on different systems the order
778        was different. A call to "sort" has been inserted into RunGrepTest for the
779        approprate test as a short-term fix. In the longer term there may be an
780        alternative.
782     3. I had an email from Eric Raymond about problems translating some of PCRE's
783        man pages to HTML (despite the fact that I distribute HTML pages, some
784        people do their own conversions for various reasons). The problems
785        concerned the use of low-level troff macros .br and .in. I have therefore
786        removed all such uses from the man pages (some were redundant, some could
787        be replaced by .nf/.fi pairs). The 132html script that I use to generate
788        HTML has been updated to handle .nf/.fi and to complain if it encounters
789        .br or .in.
791     4. Updated comments in configure.ac that get placed in config.h.in and also
792        arranged for config.h to be included in the distribution, with the name
793        config.h.generic, for the benefit of those who have to compile without
794        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
796     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
797        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
798        makevp.bat for the current PCRE, using the additional files
799        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
801     6. A Windows user reported a minor discrepancy with test 2, which turned out
802        to be caused by a trailing space on an input line that had got lost in his
803        copy. The trailing space was an accident, so I've just removed it.
805     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
806        that is needed.
808     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
809        as "const" (a) because they are and (b) because it helps the PHP
810        maintainers who have recently made a script to detect big data structures
811        in the php code that should be moved to the .rodata section. I remembered
812        to update Builducptable as well, so it won't revert if ucptable.h is ever
813        re-created.
815     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
816        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
817        order to be able to cut out the UTF-8 tables in the latter when UTF-8
818        support is not required. This saves 1.5-2K of code, which is important in
819        some applications.
821        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
822        so as not to refer to the tables, even though these functions will never be
823        called when UTF-8 support is disabled. Otherwise there are problems with a
824        shared library.
826    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
828        (a) It was defining its arguments as char * instead of void *.
830        (b) It was assuming that all moves were upwards in memory; this was true
831            a long time ago when I wrote it, but is no longer the case.
833        The emulated memove() is provided for those environments that have neither
834        memmove() nor bcopy(). I didn't think anyone used it these days, but that
835        is clearly not the case, as these two bugs were recently reported.
837    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
838        and Detrail to create the HTML documentation, the .txt form of the man
839        pages, and it removes trailing spaces from listed files. It also creates
840        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
841        case, it wraps all the #defines with #ifndefs. This script should be run
842        before "make dist".
844    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
845        with Unicode property support.
847        (a) For a maximizing quantifier, if the two different cases of the
848            character were of different lengths in their UTF-8 codings (there are
849            some cases like this - I found 11), and the matching function had to
850            back up over a mixture of the two cases, it incorrectly assumed they
851            were both the same length.
853        (b) When PCRE was configured to use the heap rather than the stack for
854            recursion during matching, it was not correctly preserving the data for
855            the other case of a UTF-8 character when checking ahead for a match
856            while processing a minimizing repeat. If the check also involved
857            matching a wide character, but failed, corruption could cause an
858            erroneous result when trying to check for a repeat of the original
859            character.
861    13. Some tidying changes to the testing mechanism:
863        (a) The RunTest script now detects the internal link size and whether there
864            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
865            values substituted by "configure". (The RunGrepTest script already did
866            this for UTF-8.) The configure.ac script no longer substitutes the
867            relevant variables.
869        (b) The debugging options /B and /D in pcretest show the compiled bytecode
870            with length and offset values. This means that the output is different
871            for different internal link sizes. Test 2 is skipped for link sizes
872            other than 2 because of this, bypassing the problem. Unfortunately,
873            there was also a test in test 3 (the locale tests) that used /B and
874            failed for link sizes other than 2. Rather than cut the whole test out,
875            I have added a new /Z option to pcretest that replaces the length and
876            offset values with spaces. This is now used to make test 3 independent
877            of link size. (Test 2 will be tidied up later.)
879    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
880        segmentation fault instead of returning the appropriate error message.
882    15. In multiline mode when the newline sequence was set to "any", the pattern
883        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
884        This doesn't seem right; it now treats the CRLF combination as the line
885        ending, and so does not match in that case. It's only a pattern such as ^$
886        that would hit this one: something like ^ABC$ would have failed after \r
887        and then tried again after \r\n.
889    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
890        in an attempt to make files that differ only in their line terminators
891        compare equal. This works on Linux.
893    17. Under certain error circumstances pcregrep might try to free random memory
894        as it exited. This is now fixed, thanks to valgrind.
896    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
897        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
898        was because its rules for how to advance for /g after matching an empty
899        string at the end of a line did not allow for this case. They now check for
900        it specially.
902    20. pcretest is supposed to handle patterns and data of any length, by
903        extending its buffers when necessary. It was getting this wrong when the
904        buffer for a data line had to be extended.
906    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
907        CRLF as a newline sequence.
909    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
910        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
911        I have nevertheless tidied it up.
913    23. Added some casts to kill warnings from HP-UX ia64 compiler.
915    24. Added a man page for pcre-config.
918    Version 7.0 19-Dec-06
919    ---------------------
921     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
922        moving to gcc 4.1.1.
924     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
925        sys/time.h, which is documented as needed for this function. It doesn't
926        seem to matter on Linux, but it showed up on some releases of OS X.
928     3. It seems that there are systems where bytes whose values are greater than
929        127 match isprint() in the "C" locale. The "C" locale should be the
930        default when a C program starts up. In most systems, only ASCII printing
931        characters match isprint(). This difference caused the output from pcretest
932        to vary, making some of the tests fail. I have changed pcretest so that:
934        (a) When it is outputting text in the compiled version of a pattern, bytes
935            other than 32-126 are always shown as hex escapes.
937        (b) When it is outputting text that is a matched part of a subject string,
938            it does the same, unless a different locale has been set for the match
939            (using the /L modifier). In this case, it uses isprint() to decide.
941     4. Fixed a major bug that caused incorrect computation of the amount of memory
942        required for a compiled pattern when options that changed within the
943        pattern affected the logic of the preliminary scan that determines the
944        length. The relevant options are -x, and -i in UTF-8 mode. The result was
945        that the computed length was too small. The symptoms of this bug were
946        either the PCRE error "internal error: code overflow" from pcre_compile(),
947        or a glibc crash with a message such as "pcretest: free(): invalid next
948        size (fast)". Examples of patterns that provoked this bug (shown in
949        pcretest format) are:
951          /(?-x: )/x
952          /(?x)(?-x: \s*#\s*)/
953          /((?i)[\x{c0}])/8
954          /(?i:[\x{c0}])/8
956        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
957        is now done differently.
959     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
960        wrapper classes; (b) implement a new function in the C++ scanner that is
961        more efficient than the old way of doing things because it avoids levels of
962        recursion in the regex matching; (c) add a paragraph to the documentation
963        for the FullMatch() function.
965     6. The escape sequence \n was being treated as whatever was defined as
966        "newline". Not only was this contrary to the documentation, which states
967        that \n is character 10 (hex 0A), but it also went horribly wrong when
968        "newline" was defined as CRLF. This has been fixed.
970     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
971        was being set to -1 for the "end of line" case (supposedly a value that no
972        character can have). Though this value is never used (the check for end of
973        line is "zero bytes in current character"), it caused compiler complaints.
974        I've changed it to 0xffffffff.
976     8. In pcre_version.c, the version string was being built by a sequence of
977        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
978        string (as it is for production releases) called a macro with an empty
979        argument. The C standard says the result of this is undefined. The gcc
980        compiler treats it as an empty string (which was what was wanted) but it is
981        reported that Visual C gives an error. The source has been hacked around to
982        avoid this problem.
984     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
985        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
986        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
987        of them did).
989    10. Originally, pcretest opened its input and output without "b"; then I was
990        told that "b" was needed in some environments, so it was added for release
991        5.0 to both the input and output. (It makes no difference on Unix-like
992        systems.) Later I was told that it is wrong for the input on Windows. I've
993        now abstracted the modes into two macros, to make it easier to fiddle with
994        them, and removed "b" from the input mode under Windows.
996    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
998    12. Added -help and --help to pcretest as an official way of being reminded
999        of the options.
1001    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1002        and pcrecpp.cc because they annoy compilers at high warning levels.
1004    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1006    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1007        scripts are not C programs :-) and which was not noticed because it works
1008        on Linux.
1010    16. pcretest is supposed to handle any length of pattern and data line (as one
1011        line or as a continued sequence of lines) by extending its input buffer if
1012        necessary. This feature was broken for very long pattern lines, leading to
1013        a string of junk being passed to pcre_compile() if the pattern was longer
1014        than about 50K.
1016    17. I have done a major re-factoring of the way pcre_compile() computes the
1017        amount of memory needed for a compiled pattern. Previously, there was code
1018        that made a preliminary scan of the pattern in order to do this. That was
1019        OK when PCRE was new, but as the facilities have expanded, it has become
1020        harder and harder to keep it in step with the real compile phase, and there
1021        have been a number of bugs (see for example, 4 above). I have now found a
1022        cunning way of running the real compile function in a "fake" mode that
1023        enables it to compute how much memory it would need, while actually only
1024        ever using a few hundred bytes of working memory and without too many
1025        tests of the mode. This should make future maintenance and development
1026        easier. A side effect of this work is that the limit of 200 on the nesting
1027        depth of parentheses has been removed (though this was never a serious
1028        limitation, I suspect). However, there is a downside: pcre_compile() now
1029        runs more slowly than before (30% or more, depending on the pattern). I
1030        hope this isn't a big issue. There is no effect on runtime performance.
1032    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1033        newline (only possible for the last line of a file) and it was a
1034        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1036    19. Added additional timing features to pcretest. (1) The -tm option now times
1037        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1038        separate command line item, by a number that specifies the number of
1039        repeats to use when timing. The default is 50000; this gives better
1040        precision, but takes uncomfortably long for very large patterns.
1042    20. Extended pcre_study() to be more clever in cases where a branch of a
1043        subpattern has no definite first character. For example, (a*|b*)[cd] would
1044        previously give no result from pcre_study(). Now it recognizes that the
1045        first character must be a, b, c, or d.
1047    21. There was an incorrect error "recursive call could loop indefinitely" if
1048        a subpattern (or the entire pattern) that was being tested for matching an
1049        empty string contained only one non-empty item after a nested subpattern.
1050        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1051        incorrectly, because the \d was being skipped in the check.
1053    22. The pcretest program now has a new pattern option /B and a command line
1054        option -b, which is equivalent to adding /B to every pattern. This causes
1055        it to show the compiled bytecode, without the additional information that
1056        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1057        is the same as /B/I).
1059    23. A new optimization is now able automatically to treat some sequences such
1060        as a*b as a*+b. More specifically, if something simple (such as a character
1061        or a simple class like \d) has an unlimited quantifier, and is followed by
1062        something that cannot possibly match the quantified thing, the quantifier
1063        is automatically "possessified".
1065    24. A recursive reference to a subpattern whose number was greater than 39
1066        went wrong under certain circumstances in UTF-8 mode. This bug could also
1067        have affected the operation of pcre_study().
1069    25. Realized that a little bit of performance could be had by replacing
1070        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1072    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1074    27. Possessive quantifiers such as a++ were previously implemented by turning
1075        them into atomic groups such as ($>a+). Now they have their own opcodes,
1076        which improves performance. This includes the automatically created ones
1077        from 23 above.
1079    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1080        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1081        the first matched character to be a colon. This applied both to named and
1082        numbered groups.
1084    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1086    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1087        building PCRE on Windows easier, so I have included it in the distribution.
1089    31. There is now a check in pcretest against a ridiculously large number being
1090        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1091        loop, the loop is abandoned.
1093    32. Forward references to subpatterns in conditions such as (?(2)...) where
1094        subpattern 2 is defined later cause pcre_compile() to search forwards in
1095        the pattern for the relevant set of parentheses. This search went wrong
1096        when there were unescaped parentheses in a character class, parentheses
1097        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1099    33. "Subroutine" calls and backreferences were previously restricted to
1100        referencing subpatterns earlier in the regex. This restriction has now
1101        been removed.
1103    34. Added a number of extra features that are going to be in Perl 5.10. On the
1104        whole, these are just syntactic alternatives for features that PCRE had
1105        previously implemented using the Python syntax or my own invention. The
1106        other formats are all retained for compatibility.
1108        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1109            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1110            also .NET compatible.
1112        (b) A recursion or subroutine call to a named group can now be defined as
1113            (?&name) as well as (?P>name).
1115        (c) A backreference to a named group can now be defined as \k<name> or
1116            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1117            5.10, are also .NET compatible.
1119        (d) A conditional reference to a named group can now use the syntax
1120            (?(<name>) or (?('name') as well as (?(name).
1122        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1123            groups (named and numbered) that are never evaluated inline, but can be
1124            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1125            is always false. There may be only one alternative in such a group.
1127        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1128            as the simple (?(R). The condition is true only if the most recent
1129            recursion is that of the given number or name. It does not search out
1130            through the entire recursion stack.
1132        (g) The escape \gN or \g{N} has been added, where N is a positive or
1133            negative number, specifying an absolute or relative reference.
1135    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1136        some "unreachable code" warnings.
1138    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1139        things, this adds five new scripts.
1141    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1142        There were also incompatibilities regarding the handling of \Q..\E inside
1143        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1144        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1146    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1147        matches an empty string, and forcibly breaks the loop. There were bugs in
1148        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1149        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1150        separate and independent bugs (that affected different cases) have been
1151        fixed.
1153    39. Refactored the code to abolish the use of different opcodes for small
1154        capturing bracket numbers. This is a tidy that I avoided doing when I
1155        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1156        The new approach is not only tidier, it makes it possible to reduce the
1157        memory needed to fix the previous bug (38).
1159    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1160        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1161        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1162        mode.
1164    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1165        report.
1167    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1168        copy construction and assignment in the C++ wrapper.
1170    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1171        couple of bugs that could have given wrong results in the "--newline=crlf"
1172        case.
1174    44. Added a number of casts and did some reorganization of signed/unsigned int
1175        variables following suggestions from Dair Grant. Also renamed the variable
1176        "this" as "item" because it is a C++ keyword.
1178    45. Arranged for dftables to add
1180          #include "pcre_internal.h"
1182        to pcre_chartables.c because without it, gcc 4.x may remove the array
1183        definition from the final binary if PCRE is built into a static library and
1184        dead code stripping is activated.
1186    46. For an unanchored pattern, if a match attempt fails at the start of a
1187        newline sequence, and the newline setting is CRLF or ANY, and the next two
1188        characters are CRLF, advance by two characters instead of one.
1191    Version 6.7 04-Jul-06
1192    ---------------------
1194     1. In order to handle tests when input lines are enormously long, pcretest has
1195        been re-factored so that it automatically extends its buffers when
1196        necessary. The code is crude, but this _is_ just a test program. The
1197        default size has been increased from 32K to 50K.
1199     2. The code in pcre_study() was using the value of the re argument before
1200        testing it for NULL. (Of course, in any sensible call of the function, it
1201        won't be NULL.)
1203     3. The memmove() emulation function in pcre_internal.h, which is used on
1204        systems that lack both memmove() and bcopy() - that is, hardly ever -
1205        was missing a "static" storage class specifier.
1207     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1208        containing an extended class (one that cannot be represented by a bitmap
1209        because it contains high-valued characters or Unicode property items, e.g.
1210        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1211        pattern, but PCRE should not loop if you do not (it no longer does).
1212        [Detail: two cases were found: (a) a repeated subpattern containing an
1213        extended class; (b) a recursive reference to a subpattern that followed a
1214        previous extended class. It wasn't skipping over the extended class
1215        correctly when UTF-8 mode was not set.]
1217     5. A negated single-character class was not being recognized as fixed-length
1218        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1219        compile error "lookbehind assertion is not fixed length".
1221     6. The RunPerlTest auxiliary script was showing an unexpected difference
1222        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1223        write a Perl script that can interpret lines of an input file either as
1224        byte characters or as UTF-8, which is what "perltest" was being required to
1225        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1226        can't do is switch easily at run time between having the "use utf8;" pragma
1227        or not. In the end, I fudged it by using the RunPerlTest script to insert
1228        "use utf8;" explicitly for the UTF-8 tests.
1230     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1231        the end of the subject string, contrary to the documentation and to what
1232        Perl does. This was true of both matching functions. Now it matches only at
1233        the start of the subject and immediately after *internal* newlines.
1235     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1236        a pointer to an int instead of a pointer to an unsigned long int. This
1237        caused problems on 64-bit systems.
1239     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1240        instance of the 'standard' template library not being so standard".
1242    10. There was no check on the number of named subpatterns nor the maximum
1243        length of a subpattern name. The product of these values is used to compute
1244        the size of the memory block for a compiled pattern. By supplying a very
1245        long subpattern name and a large number of named subpatterns, the size
1246        computation could be caused to overflow. This is now prevented by limiting
1247        the length of names to 32 characters, and the number of named subpatterns
1248        to 10,000.
1250    11. Subpatterns that are repeated with specific counts have to be replicated in
1251        the compiled pattern. The size of memory for this was computed from the
1252        length of the subpattern and the repeat count. The latter is limited to
1253        65535, but there was no limit on the former, meaning that integer overflow
1254        could in principle occur. The compiled length of a repeated subpattern is
1255        now limited to 30,000 bytes in order to prevent this.
1257    12. Added the optional facility to have named substrings with the same name.
1259    13. Added the ability to use a named substring as a condition, using the
1260        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1261        are numbers (not recommended). Forward references are permitted.
1263    14. Added forward references in named backreferences (if you see what I mean).
1265    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1266        pattern could run off the end of the subject. For example, the pattern
1267        "(?s)(.{1,5})"8 did this with the subject "ab".
1269    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1270        PCRE_CASELESS was set when matching characters that were quantified with ?
1271        or *.
1273    17. A character class other than a single negated character that had a minimum
1274        but no maximum quantifier - for example [ab]{6,} - was not handled
1275        correctly by pce_dfa_exec(). It would match only one character.
1277    18. A valid (though odd) pattern that looked like a POSIX character
1278        class but used an invalid character after [ (for example [[,abc,]]) caused
1279        pcre_compile() to give the error "Failed: internal error: code overflow" or
1280        in some cases to crash with a glibc free() error. This could even happen if
1281        the pattern terminated after [[ but there just happened to be a sequence of
1282        letters, a binary zero, and a closing ] in the memory that followed.
1284    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1285        over the years. Originally (before any Unicode support), just the bottom 8
1286        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1287        output from "man perlunicode" includes this:
1289          The regular expression compiler produces polymorphic opcodes.  That
1290          is, the pattern adapts to the data and automatically switches to
1291          the Unicode character scheme when presented with Unicode data--or
1292          instead uses a traditional byte scheme when presented with byte
1293          data.
1295        Sadly, a wide octal escape does not cause a switch, and in a string with
1296        no other multibyte characters, these octal escapes are treated as before.
1297        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1298        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1299        Unicode string.
1301        I have not perpetrated such confusion in PCRE. Up till now, it took just
1302        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1303        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1304        translate to the appropriate multibyte character.
1306    29. Applied some refactoring to reduce the number of warnings from Microsoft
1307        and Borland compilers. This has included removing the fudge introduced
1308        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1309        a warning about an unused variable.
1311    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1312        characters since release 4.0, because Perl (from release 5.004) does not.
1313        [Or at least, is documented not to: some releases seem to be in conflict
1314        with the documentation.] However, when a pattern was studied with
1315        pcre_study() and all its branches started with \s, PCRE still included VT
1316        as a possible starting character. Of course, this did no harm; it just
1317        caused an unnecessary match attempt.
1319    22. Removed a now-redundant internal flag bit that recorded the fact that case
1320        dependency changed within the pattern. This was once needed for "required
1321        byte" processing, but is no longer used. This recovers a now-scarce options
1322        bit. Also moved the least significant internal flag bit to the most-
1323        significant bit of the word, which was not previously used (hangover from
1324        the days when it was an int rather than a uint) to free up another bit for
1325        the future.
1327    23. Added support for CRLF line endings as well as CR and LF. As well as the
1328        default being selectable at build time, it can now be changed at runtime
1329        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1330        specify that it is scanning data with non-default line endings.
1332    24. Changed the definition of CXXLINK to make it agree with the definition of
1333        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1335    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1336        recursions. This makes a big different to stack usage for some patterns.
1338    26. If a subpattern containing a named recursion or subroutine reference such
1339        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1340        the space required for the compiled pattern went wrong and gave too small a
1341        value. Depending on the environment, this could lead to "Failed: internal
1342        error: code overflow at offset 49" or "glibc detected double free or
1343        corruption" errors.
1345    27. Applied patches from Google (a) to support the new newline modes and (b) to
1346        advance over multibyte UTF-8 characters in GlobalReplace.
1348    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1349        difference for some implementation of PCRE in some Windows version.
1351    29. Added some extra testing facilities to pcretest:
1353        \q<number>   in a data line sets the "match limit" value
1354        \Q<number>   in a data line sets the "match recursion limt" value
1355        -S <number>  sets the stack size, where <number> is in megabytes
1357        The -S option isn't available for Windows.
1360    Version 6.6 06-Feb-06
1361    ---------------------
1363     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1364        in pcreposix.h. I have copied the definition from pcre.h.
1366     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1367        because pcre.h is no longer a built file.
1369     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1370        not normally included in the compiled code.
1373    Version 6.5 01-Feb-06
1374    ---------------------
1376     1. When using the partial match feature with pcre_dfa_exec(), it was not
1377        anchoring the second and subsequent partial matches at the new starting
1378        point. This could lead to incorrect results. For example, with the pattern
1379        /1234/, partially matching against "123" and then "a4" gave a match.
1381     2. Changes to pcregrep:
1383        (a) All non-match returns from pcre_exec() were being treated as failures
1384            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1385            error message is output. Some extra information is given for the
1386            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1387            probably the only errors that are likely to be caused by users (by
1388            specifying a regex that has nested indefinite repeats, for instance).
1389            If there are more than 20 of these errors, pcregrep is abandoned.
1391        (b) A binary zero was treated as data while matching, but terminated the
1392            output line if it was written out. This has been fixed: binary zeroes
1393            are now no different to any other data bytes.
1395        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1396            used to set a locale for matching. The --locale=xxxx long option has
1397            been added (no short equivalent) to specify a locale explicitly on the
1398            pcregrep command, overriding the environment variables.
1400        (d) When -B was used with -n, some line numbers in the output were one less
1401            than they should have been.
1403        (e) Added the -o (--only-matching) option.
1405        (f) If -A or -C was used with -c (count only), some lines of context were
1406            accidentally printed for the final match.
1408        (g) Added the -H (--with-filename) option.
1410        (h) The combination of options -rh failed to suppress file names for files
1411            that were found from directory arguments.
1413        (i) Added the -D (--devices) and -d (--directories) options.
1415        (j) Added the -F (--fixed-strings) option.
1417        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1419        (l) Added the --colo(u)r option.
1421        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1422            is not present by default.
1424     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1425        items such as (?R) or (?1), when the recursion could match a number of
1426        alternatives. If it matched one of the alternatives, but subsequently,
1427        outside the recursion, there was a failure, the code tried to back up into
1428        the recursion. However, because of the way PCRE is implemented, this is not
1429        possible, and the result was an incorrect result from the match.
1431        In order to prevent this happening, the specification of recursion has
1432        been changed so that all such subpatterns are automatically treated as
1433        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1435     4. I had overlooked the fact that, in some locales, there are characters for
1436        which isalpha() is true but neither isupper() nor islower() are true. In
1437        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1438        and ordfeminine) are like this. This affected the treatment of \w and \W
1439        when they appeared in character classes, but not when they appeared outside
1440        a character class. The bit map for "word" characters is now created
1441        separately from the results of isalnum() instead of just taking it from the
1442        upper, lower, and digit maps. (Plus the underscore character, of course.)
1444     5. The above bug also affected the handling of POSIX character classes such as
1445        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1446        permanent tables. Instead, the bit maps for such a class were previously
1447        created as the appropriate unions of the upper, lower, and digit bitmaps.
1448        Now they are created by subtraction from the [[:word:]] class, which has
1449        its own bitmap.
1451     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1452        It is created by subtracting the vertical space characters (\x09, \x0a,
1453        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1454        subtraction was done in the overall bitmap for a character class, meaning
1455        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1456        be recognized. This bug has been fixed.
1458     7. Patches from the folks at Google:
1460          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1461          real life, but is still worth protecting against".
1463          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1464          regular expressions".
1466          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1467          have it.
1469          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1470          "configure" and the latter not, in order to fix a problem somebody had
1471          with compiling the Arg class on HP-UX.
1473          (e) Improve the error-handling of the C++ wrapper a little bit.
1475          (f) New tests for checking recursion limiting.
1477     8. The pcre_memmove() function, which is used only if the environment does not
1478        have a standard memmove() function (and is therefore rarely compiled),
1479        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1480        returning a result (though PCRE never actually uses the result).
1482     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1483        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1484        returned instead of calling malloc() with an overflowing number that would
1485        most likely cause subsequent chaos.
1487    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1489    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1490        with this option is matched, the nmatch and pmatch options of regexec() are
1491        ignored.
1493    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1494        provided in case anyone wants to the the POSIX interface with UTF-8
1495        strings.
1497    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1498        C++ linking (needed for some HP-UX environments).
1500    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1501        (unused parameter) and in the pcre_printint() function (omitted "default"
1502        switch label when the default is to do nothing).
1504    15. Added some code to make it possible, when PCRE is compiled as a C++
1505        library, to replace subject pointers for pcre_exec() with a smart pointer
1506        class, thus making it possible to process discontinuous strings.
1508    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1509        much the same function. They were added by different people who were trying
1510        to make PCRE easy to compile on non-Unix systems. It has been suggested
1511        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1512        for compiling on Windows systems. I have therefore replaced it with
1513        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1514        defaults to "extern" for C or "extern C" for C++, which works fine on
1515        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1516        SCOPE with something explicit in config.h. In addition:
1518        (a) pcreposix.h still had just "extern" instead of either of these macros;
1519            I have replaced it with PCRE_DATA_SCOPE.
1521        (b) Functions such as _pcre_xclass(), which are internal to the library,
1522            but external in the C sense, all had PCRE_EXPORT in their definitions.
1523            This is apparently wrong for the Windows case, so I have removed it.
1524            (It makes no difference on Unix-like systems.)
1526    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1527        of recursive calls to match(). This is different to MATCH_LIMIT because
1528        that limits the total number of calls to match(), not all of which increase
1529        the depth of recursion. Limiting the recursion depth limits the amount of
1530        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1531        when PCRE is compiled, and changed at run time. A patch from Google adds
1532        this functionality to the C++ interface.
1534    18. Changes to the handling of Unicode character properties:
1536        (a) Updated the table to Unicode 4.1.0.
1538        (b) Recognize characters that are not in the table as "Cn" (undefined).
1540        (c) I revised the way the table is implemented to a much improved format
1541            which includes recognition of ranges. It now supports the ranges that
1542            are defined in UnicodeData.txt, and it also amalgamates other
1543            characters into ranges. This has reduced the number of entries in the
1544            table from around 16,000 to around 3,000, thus reducing its size
1545            considerably. I realized I did not need to use a tree structure after
1546            all - a binary chop search is just as efficient. Having reduced the
1547            number of entries, I extended their size from 6 bytes to 8 bytes to
1548            allow for more data.
1550        (d) Added support for Unicode script names via properties such as \p{Han}.
1552    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1553        matching that character.
1555    20. When matching a repeated Unicode property with a minimum greater than zero,
1556        (for example \pL{2,}), PCRE could look past the end of the subject if it
1557        reached it while seeking the minimum number of characters. This could
1558        happen only if some of the characters were more than one byte long, because
1559        there is a check for at least the minimum number of bytes.
1561    21. Refactored the implementation of \p and \P so as to be more general, to
1562        allow for more different types of property in future. This has changed the
1563        compiled form incompatibly. Anybody with saved compiled patterns that use
1564        \p or \P will have to recompile them.
1566    22. Added "Any" and "L&" to the supported property types.
1568    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1569        but give a compile time error if the value is greater than 0xff.
1571    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1572        accidentally not being installed or uninstalled.
1574    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1575        made were to insert the current release number. This seemed silly, because
1576        it made things harder for people building PCRE on systems that don't run
1577        "configure". I have turned pcre.h into a distributed file, no longer built
1578        by "configure", with the version identification directly included. There is
1579        no longer a pcre.h.in file.
1581        However, this change necessitated a change to the pcre-config script as
1582        well. It is built from pcre-config.in, and one of the substitutions was the
1583        release number. I have updated configure.ac so that ./configure now finds
1584        the release number by grepping pcre.h.
1586    26. Added the ability to run the tests under valgrind.
1589    Version 6.4 05-Sep-05
1590    ---------------------
1592     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1593        "--" to be printed when multiple files were scanned, even when none of the
1594        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1595        consider it to be a bug, and have restored the previous behaviour.
1597     2. A couple of code tidies to get rid of compiler warnings.
1599     3. The pcretest program used to cheat by referring to symbols in the library
1600        whose names begin with _pcre_. These are internal symbols that are not
1601        really supposed to be visible externally, and in some environments it is
1602        possible to suppress them. The cheating is now confined to including
1603        certain files from the library's source, which is a bit cleaner.
1605     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1606        file's purpose clearer.
1608     5. Reorganized pcre_ucp_findchar().
1611    Version 6.3 15-Aug-05
1612    ---------------------
1614     1. The file libpcre.pc.in did not have general read permission in the tarball.
1616     2. There were some problems when building without C++ support:
1618        (a) If C++ support was not built, "make install" and "make test" still
1619            tried to test it.
1621        (b) There were problems when the value of CXX was explicitly set. Some
1622            changes have been made to try to fix these, and ...
1624        (c) --disable-cpp can now be used to explicitly disable C++ support.
1626        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1627            backslash in a target when C++ was disabled. This confuses some
1628            versions of "make", apparently. Using an intermediate variable solves
1629            this. (Same for CPP_LOBJ.)
1631     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1632        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1633        necessary on certain architectures.
1635     4. Added a setting of -export-symbols-regex to the link command to remove
1636        those symbols that are exported in the C sense, but actually are local
1637        within the library, and not documented. Their names all begin with
1638        "_pcre_". This is not a perfect job, because (a) we have to except some
1639        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1640        available (and never for static libraries). I have made a note to try to
1641        find a way round (a) in the future.
1644    Version 6.2 01-Aug-05
1645    ---------------------
1647     1. There was no test for integer overflow of quantifier values. A construction
1648        such as {1111111111111111} would give undefined results. What is worse, if
1649        a minimum quantifier for a parenthesized subpattern overflowed and became
1650        negative, the calculation of the memory size went wrong. This could have
1651        led to memory overwriting.
1653     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1655     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1656        operating environments where this matters.
1658     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1659        PCRE options from within the C++ wrapper.
1661     5. Named capturing subpatterns were not being correctly counted when a pattern
1662        was compiled. This caused two problems: (a) If there were more than 100
1663        such subpatterns, the calculation of the memory needed for the whole
1664        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1665        back references of the form \12, where the number was greater than 9, were
1666        not recognized as back references, even though there were sufficient
1667        previous subpatterns.
1669     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1670        versions of gcc, e.g. 2.95.4.
1673    Version 6.1 21-Jun-05
1674    ---------------------
1676     1. There was one reference to the variable "posix" in pcretest.c that was not
1677        surrounded by "#if !defined NOPOSIX".
1679     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1680        the cross-check on the old pcre_info() function, for the benefit of the
1681        cut-down version of PCRE that is currently imported into Exim.
1683     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1684        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1685        patterns that start (?i) but I don't think that matters. The use of (?i) is
1686        just an example; this all applies to the other options as well.
1688     4. Since libtool seems to echo the compile commands it is issuing, the output
1689        from "make" can be reduced a bit by putting "@" in front of each libtool
1690        compile command.
1692     5. Patch from the folks at Google for configure.in to be a bit more thorough
1693        in checking for a suitable C++ installation before trying to compile the
1694        C++ stuff. This should fix a reported problem when a compiler was present,
1695        but no suitable headers.
1697     6. The man pages all had just "PCRE" as their title. I have changed them to
1698        be the relevant file name. I have also arranged that these names are
1699        retained in the file doc/pcre.txt, which is a concatenation in text format
1700        of all the man pages except the little individual ones for each function.
1702     7. The NON-UNIX-USE file had not been updated for the different set of source
1703        files that come with release 6. I also added a few comments about the C++
1704        wrapper.
1707    Version 6.0 07-Jun-05
1708    ---------------------
1710     1. Some minor internal re-organization to help with my DFA experiments.
1712     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1713        didn't matter for the library itself when fully configured, but did matter
1714        when compiling without UCP support, or within Exim, where the ucp files are
1715        not imported.
1717     3. Refactoring of the library code to split up the various functions into
1718        different source modules. The addition of the new DFA matching code (see
1719        below) to a single monolithic source would have made it really too
1720        unwieldy, quite apart from causing all the code to be include in a
1721        statically linked application, when only some functions are used. This is
1722        relevant even without the DFA addition now that patterns can be compiled in
1723        one application and matched in another.
1725        The downside of splitting up is that there have to be some external
1726        functions and data tables that are used internally in different modules of
1727        the library but which are not part of the API. These have all had their
1728        names changed to start with "_pcre_" so that they are unlikely to clash
1729        with other external names.
1731     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1732        a different (DFA) algorithm. Although it is slower than the original
1733        function, it does have some advantages for certain types of matching
1734        problem.
1736     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1737        including restarting after a partial match.
1739     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1740        defined when compiling for Windows was sent to me. I have put it into the
1741        code, though I have no means of testing or verifying it.
1743     7. Added the pcre_refcount() auxiliary function.
1745     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1746        match before or at the first newline in the subject string. In pcretest,
1747        the /f option on a pattern can be used to set this.
1749     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1750        would behave wrongly. This has been present in PCRE since release 4.0.
1752    10. A number of changes to the pcregrep command:
1754        (a) Refactored how -x works; insert ^(...)$ instead of setting
1755            PCRE_ANCHORED and checking the length, in preparation for adding
1756            something similar for -w.
1758        (b) Added the -w (match as a word) option.
1760        (c) Refactored the way lines are read and buffered so as to have more
1761            than one at a time available.
1763        (d) Implemented a pcregrep test script.
1765        (e) Added the -M (multiline match) option. This allows patterns to match
1766            over several lines of the subject. The buffering ensures that at least
1767            8K, or the rest of the document (whichever is the shorter) is available
1768            for matching (and similarly the previous 8K for lookbehind assertions).
1770        (f) Changed the --help output so that it now says
1772              -w, --word-regex(p)
1774            instead of two lines, one with "regex" and the other with "regexp"
1775            because that confused at least one person since the short forms are the
1776            same. (This required a bit of code, as the output is generated
1777            automatically from a table. It wasn't just a text change.)
1779        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1780            option but starts with a hyphen. Could be a pattern or a path name
1781            starting with a hyphen, for instance.
1783        (h) "-" can be given as a file name to represent stdin.
1785        (i) When file names are being printed, "(standard input)" is used for
1786            the standard input, for compatibility with GNU grep. Previously
1787            "<stdin>" was used.
1789        (j) The option --label=xxx can be used to supply a name to be used for
1790            stdin when file names are being printed. There is no short form.
1792        (k) Re-factored the options decoding logic because we are going to add
1793            two more options that take data. Such options can now be given in four
1794            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1796        (l) Added the -A, -B, and -C options for requesting that lines of context
1797            around matches be printed.
1799        (m) Added the -L option to print the names of files that do not contain
1800            any matching lines, that is, the complement of -l.
1802        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1803            continue to scan other files.
1805        (o) The -s option was incorrectly implemented. For compatibility with other
1806            greps, it now suppresses the error message for a non-existent or non-
1807            accessible file (but not the return code). There is a new option called
1808            -q that suppresses the output of matching lines, which was what -s was
1809            previously doing.
1811        (p) Added --include and --exclude options to specify files for inclusion
1812            and exclusion when recursing.
1814    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1815        Hopefully, it now does.
1817    12. Missing cast in pcre_study().
1819    13. Added an "uninstall" target to the makefile.
1821    14. Replaced "extern" in the function prototypes in Makefile.in with
1822        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1823        world, but is set differently for Windows.
1825    15. Added a second compiling function called pcre_compile2(). The only
1826        difference is that it has an extra argument, which is a pointer to an
1827        integer error code. When there is a compile-time failure, this is set
1828        non-zero, in addition to the error test pointer being set to point to an
1829        error message. The new argument may be NULL if no error number is required
1830        (but then you may as well call pcre_compile(), which is now just a
1831        wrapper). This facility is provided because some applications need a
1832        numeric error indication, but it has also enabled me to tidy up the way
1833        compile-time errors are handled in the POSIX wrapper.
1835    16. Added VPATH=.libs to the makefile; this should help when building with one
1836        prefix path and installing with another. (Or so I'm told by someone who
1837        knows more about this stuff than I do.)
1839    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1840        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1841        match everything, including newlines. This is not POSIX-compatible, but
1842        somebody wanted the feature. From pcretest it can be activated by using
1843        both the P and the s flags.
1845    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1847    19. libpcre.pc was being incorrectly installed as executable.
1849    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1850        it now also looks for '\r' so that it will work unmodified on Windows.
1852    21. Added Google's contributed C++ wrapper to the distribution.
1854    22. Added some untidy missing memory free() calls in pcretest, to keep
1855        Electric Fence happy when testing.
1859    Version 5.0 13-Sep-04
1860    ---------------------
1862     1. Internal change: literal characters are no longer packed up into items
1863        containing multiple characters in a single byte-string. Each character
1864        is now matched using a separate opcode. However, there may be more than one
1865        byte in the character in UTF-8 mode.
1867     2. The pcre_callout_block structure has two new fields: pattern_position and
1868        next_item_length. These contain the offset in the pattern to the next match
1869        item, and its length, respectively.
1871     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1872        insertion of callouts before each pattern item. Added the /C option to
1873        pcretest to make use of this.
1875     4. On the advice of a Windows user, the lines
1877          #if defined(_WIN32) || defined(WIN32)
1878          _setmode( _fileno( stdout ), 0x8000 );
1879          #endif  /* defined(_WIN32) || defined(WIN32) */
1881        have been added to the source of pcretest. This apparently does useful
1882        magic in relation to line terminators.
1884     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1885        for the benefit of those environments where the "b" makes a difference.
1887     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1888        to know about it. I have put a hack into configure.in that adds in code
1889        to set GCC=yes if CC=icc. This seems to end up at a point in the
1890        generated configure script that is early enough to affect the setting of
1891        compiler options, which is what is needed, but I have no means of testing
1892        whether it really works. (The user who reported this had patched the
1893        generated configure script, which of course I cannot do.)
1895        LATER: After change 22 below (new libtool files), the configure script
1896        seems to know about icc (and also ecc). Therefore, I have commented out
1897        this hack in configure.in.
1899     7. Added support for pkg-config (2 patches were sent in).
1901     8. Negated POSIX character classes that used a combination of internal tables
1902        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1903        [[:^ascii]]. Typically, they would match almost any characters. The other
1904        POSIX classes were not broken in this way.
1906     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1907        to find the match, as PCRE was deluded into thinking that the match had to
1908        start at the start point or following a newline. The same bug applied to
1909        patterns with negative forward assertions or any backward assertions
1910        preceding ".*" at the start, unless the pattern required a fixed first
1911        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1913    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1914        starting at the last subject character, bytes beyond the end of the subject
1915        string were read.
1917    11. Renamed the variable "class" as "classbits" to make life easier for C++
1918        users. (Previously there was a macro definition, but it apparently wasn't
1919        enough.)
1921    12. Added the new field "tables" to the extra data so that tables can be passed
1922        in at exec time, or the internal tables can be re-selected. This allows
1923        a compiled regex to be saved and re-used at a later time by a different
1924        program that might have everything at different addresses.
1926    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1927        -R library as well as a -L library.
1929    14. The debugging options of pcretest (-d on the command line or D on a
1930        pattern) showed incorrect output for anything following an extended class
1931        that contained multibyte characters and which was followed by a quantifier.
1933    15. Added optional support for general category Unicode character properties
1934        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1935        support. It adds about 90K to the size of the library. The meanings of the
1936        inbuilt class escapes such as \d and \s have NOT been changed.
1938    16. Updated pcredemo.c to include calls to free() to release the memory for the
1939        compiled pattern.
1941    17. The generated file chartables.c was being created in the source directory
1942        instead of in the building directory. This caused the build to fail if the
1943        source directory was different from the building directory, and was
1944        read-only.
1946    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1947        file. No doubt somebody will tell me if they don't make sense... Also added
1948        Dan Mooney's comments about building on OpenVMS.
1950    19. Added support for partial matching via the PCRE_PARTIAL option for
1951        pcre_exec() and the \P data escape in pcretest.
1953    20. Extended pcretest with 3 new pattern features:
1955        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1956              write the compiled pattern to the file whose name is "rest-of-line".
1957              This is a straight binary dump of the data, with the saved pointer to
1958              the character tables forced to be NULL. The study data, if any, is
1959              written too. After writing, pcretest reads a new pattern.
1961        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1962              compiled pattern from the given file. There must not be any
1963              occurrences of "<" in the file name (pretty unlikely); if there are,
1964              pcretest will instead treat the initial "<" as a pattern delimiter.
1965              After reading in the pattern, pcretest goes on to read data lines as
1966              usual.
1968        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1969              and 16-bit fields in a compiled pattern, to simulate a pattern that
1970              was compiled on a host of opposite endianness.
1972    21. The pcre-exec() function can now cope with patterns that were compiled on
1973        hosts of opposite endianness, with this restriction:
1975          As for any compiled expression that is saved and used later, the tables
1976          pointer field cannot be preserved; the extra_data field in the arguments
1977          to pcre_exec() should be used to pass in a tables address if a value
1978          other than the default internal tables were used at compile time.
1980    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1981        now diagnosed as an error. Previously, most of the time, a negative number
1982        would have been treated as zero, but if in addition "ovector" was passed as
1983        NULL, a crash could occur.
1985    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1986        new versions from the libtool 1.5 distribution (the last one is a copy of
1987        a file called libtool.m4). This seems to have fixed the need to patch
1988        "configure" to support Darwin 1.3 (which I used to do). However, I still
1989        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1990        workstation).
1992    24. Changed the PCRE licence to be the more standard "BSD" licence.
1995    Version 4.5 01-Dec-03
1996    ---------------------
1998     1. There has been some re-arrangement of the code for the match() function so
1999        that it can be compiled in a version that does not call itself recursively.
2000        Instead, it keeps those local variables that need separate instances for
2001        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2002        needs to "recurse". Keeping track of where control must go is done by means
2003        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2004        hide most of the details from the main code, and operates only if
2005        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2006        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2007        operating.
2009        To make it easier for callers to provide specially tailored get/free
2010        functions for this usage, two new functions, pcre_stack_malloc, and
2011        pcre_stack_free, are used. They are always called in strict stacking order,
2012        and the size of block requested is always the same.
2014        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2015        PCRE has been compiled to use the stack or the heap for recursion. The
2016        -C option of pcretest uses this to show which version is compiled.
2018        A new data escape \S, is added to pcretest; it causes the amounts of store
2019        obtained and freed by both kinds of malloc/free at match time to be added
2020        to the output.
2022     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2023        what's available on my current Linux desktop machine.
2025     3. When matching a UTF-8 string, the test for a valid string at the start has
2026        been extended. If start_offset is not zero, PCRE now checks that it points
2027        to a byte that is the start of a UTF-8 character. If not, it returns
2028        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2029        this is necessary because there may be backward assertions in the pattern.
2030        When matching the same subject several times, it may save resources to use
2031        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2033     4. The code for checking the validity of UTF-8 strings has been tightened so
2034        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2035        containing "overlong sequences".
2037     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2038        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2039        should have been "&", but it just so happened that all the cases this let
2040        through by mistake were picked up later in the function.
2042     6. I had used a variable called "isblank" - this is a C99 function, causing
2043        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2045     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2046        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2047        so the version is shown; (c) stop "make test" echoing "./RunTest".
2049     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2051     9. The prototype for memmove() for systems that don't have it was using
2052        size_t, but the inclusion of the header that defines size_t was later. I've
2053        moved the #includes for the C headers earlier to avoid this.
2055    10. Added some adjustments to the code to make it easier to compiler on certain
2056        special systems:
2058          (a) Some "const" qualifiers were missing.
2059          (b) Added the macro EXPORT before all exported functions; by default this
2060              is defined to be empty.
2061          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2062              that it reads its output file name as an argument instead of writing
2063              to the standard output and assuming this can be redirected.
2065    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2066        class containing characters with values greater than 255, PCRE compilation
2067        went into a loop.
2069    12. A recursive reference to a subpattern that was within another subpattern
2070        that had a minimum quantifier of zero caused PCRE to crash. For example,
2071        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2072        recursion. If the recursively-called subpattern itself had a zero repeat,
2073        that was OK.
2075    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2076        buffer into which it was copied (for escape processing) was still set at
2077        1024, so long lines caused crashes.
2079    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2080        "internal error: code overflow...". This applied to any character class
2081        that was followed by a possessive quantifier.
2083    15. Modified the Makefile to add libpcre.la as a prerequisite for
2084        libpcreposix.la because I was told this is needed for a parallel build to
2085        work.
2087    16. If a pattern that contained .* following optional items at the start was
2088        studied, the wrong optimizing data was generated, leading to matching
2089        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2090        matching string must start with a or b or c. The correct conclusion for
2091        this pattern is that a match can start with any character.
2094    Version 4.4 13-Aug-03
2095    ---------------------
2097     1. In UTF-8 mode, a character class containing characters with values between
2098        127 and 255 was not handled correctly if the compiled pattern was studied.
2099        In fixing this, I have also improved the studying algorithm for such
2100        classes (slightly).
2102     2. Three internal functions had redundant arguments passed to them. Removal
2103        might give a very teeny performance improvement.
2105     3. Documentation bug: the value of the capture_top field in a callout is *one
2106        more than* the number of the hightest numbered captured substring.
2108     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2109        in incorrectly linking with a previously installed version. They now link
2110        explicitly with libpcre.la.
2112     5. configure.in no longer needs to recognize Cygwin specially.
2114     6. A problem in pcre.in for Windows platforms is fixed.
2116     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2117        pcretest, it used to include the size of the study block as part of its
2118        output. Unfortunately, the structure contains a field that has a different
2119        size on different hardware architectures. This meant that the tests that
2120        showed this size failed. As the block is currently always of a fixed size,
2121        this information isn't actually particularly useful in pcretest output, so
2122        I have just removed it.
2124     8. Three pre-processor statements accidentally did not start in column 1.
2125        Sadly, there are *still* compilers around that complain, even though
2126        standard C has not required this for well over a decade. Sigh.
2128     9. In pcretest, the code for checking callouts passed small integers in the
2129        callout_data field, which is a void * field. However, some picky compilers
2130        complained about the casts involved for this on 64-bit systems. Now
2131        pcretest passes the address of the small integer instead, which should get
2132        rid of the warnings.
2134    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2135        both compile and run time, and gives an error if an invalid UTF-8 sequence
2136        is found. There is a option for disabling this check in cases where the
2137        string is known to be correct and/or the maximum performance is wanted.
2139    11. In response to a bug report, I changed one line in Makefile.in from
2141            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2142        to
2143            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2145        to look similar to other lines, but I have no way of telling whether this
2146        is the right thing to do, as I do not use Windows. No doubt I'll get told
2147        if it's wrong...
2150    Version 4.3 21-May-03
2151    ---------------------
2153    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2154       Makefile.
2156    2. Some refactoring to improve the quality of the code:
2158       (i)   The utf8_table... variables are now declared "const".
2160       (ii)  The code for \cx, which used the "case flipping" table to upper case
2161             lower case letters, now just substracts 32. This is ASCII-specific,
2162             but the whole concept of \cx is ASCII-specific, so it seems
2163             reasonable.
2165       (iii) PCRE was using its character types table to recognize decimal and
2166             hexadecimal digits in the pattern. This is silly, because it handles
2167             only 0-9, a-f, and A-F, but the character types table is locale-
2168             specific, which means strange things might happen. A private
2169             table is now used for this - though it costs 256 bytes, a table is
2170             much faster than multiple explicit tests. Of course, the standard
2171             character types table is still used for matching digits in subject
2172             strings against \d.
2174       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2175             ending in _t are). So I've renamed it as ESC_tee.
2177    3. The first argument for regexec() in the POSIX wrapper should have been
2178       defined as "const".
2180    4. Changed pcretest to use malloc() for its buffers so that they can be
2181       Electric Fenced for debugging.
2183    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2184       to read one or more bytes before the start of the subject string. Often this
2185       had no effect on PCRE's behaviour, but in some circumstances it could
2186       provoke a segmentation fault.
2188    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2189       to try to read one or more bytes before the start of the subject string.
2191    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2192       UTF-8 support could misbehave in various ways if the subject string
2193       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2194       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2195       back over UTF-8 characters.)
2198    Version 4.2 14-Apr-03
2199    ---------------------
2201    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2203    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2204         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2205         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2206         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2207         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2208           and BUILD_EXEEXT
2209         Note: automatic setting of the BUILD variables is not yet working
2210         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2211           compile-time but not at link-time
2212         [LINK]: use for linking executables only
2213         make different versions for Windows and non-Windows
2214         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2215           libraries
2216         [LINK_FOR_BUILD]: new variable
2217         [OBJEXT]: use throughout
2218         [EXEEXT]: use throughout
2219         <winshared>: new target
2220         <wininstall>: new target
2221         <dftables.o>: use native compiler
2222         <dftables>: use native linker
2223         <install>: handle Windows platform correctly
2224         <clean>: ditto
2225         <check>: ditto
2226         copy DLL to top builddir before testing
2228       As part of these changes, -no-undefined was removed again. This was reported
2229       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2230       in any case.
2232    3. Some tidies to get rid of compiler warnings:
2234       . In the match_data structure, match_limit was an unsigned long int, whereas
2235         match_call_count was an int. I've made them both unsigned long ints.
2237       . In pcretest the fact that a const uschar * doesn't automatically cast to
2238         a void * provoked a warning.
2240       . Turning on some more compiler warnings threw up some "shadow" variables
2241         and a few more missing casts.
2243    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2244       option, a class that contained a single character with a value between 128
2245       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2247    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2248       option, a class that contained several characters, but with at least one
2249       whose value was between 128 and 255 caused PCRE to crash.
2252    Version 4.1 12-Mar-03
2253    ---------------------
2255    1. Compiling with gcc -pedantic found a couple of places where casts were
2256    needed, and a string in dftables.c that was longer than standard compilers are
2257    required to support.
2259    2. Compiling with Sun's compiler found a few more places where the code could
2260    be tidied up in order to avoid warnings.
2262    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2263    first of these names is deprecated in the latest Autoconf in favour of the name
2264    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2265    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2266    analogy I have changed it to CFLAGS_FOR_BUILD.
2268    4. Added -no-undefined to the linking command in the Makefile, because this is
2269    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2270    linking step for the pcreposix library.
2272    5. PCRE was failing to diagnose the case of two named groups with the same
2273    name.
2275    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2276    literal character that is needed in the subject for a match, and scans along to
2277    ensure that it is present before embarking on the full matching process. This
2278    saves time in cases of nested unlimited repeats that are never going to match.
2279    Problem: the scan can take a lot of time if the subject is very long (e.g.
2280    megabytes), thus penalizing straightforward matches. It is now done only if the
2281    amount of subject to be scanned is less than 1000 bytes.
2283    7. A lesser problem with the same optimization is that it was recording the
2284    first character of an anchored pattern as "needed", thus provoking a search
2285    right along the subject, even when the first match of the pattern was going to
2286    fail. The "needed" character is now not set for anchored patterns, unless it
2287    follows something in the pattern that is of non-fixed length. Thus, it still
2288    fulfils its original purpose of finding quick non-matches in cases of nested
2289    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2292    Version 4.0 17-Feb-03
2293    ---------------------
2295    1. If a comment in an extended regex that started immediately after a meta-item
2296    extended to the end of string, PCRE compiled incorrect data. This could lead to
2297    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2299    2. Moved to autoconf 2.53 and libtool 1.4.2.
2301    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2302    the special perltest8 script is no longer needed - all the tests can be run
2303    from a single perltest script.
2305    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2306    by \s. It has now been removed in PCRE. This means it isn't recognized as
2307    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2308    class [:space:] *does* include VT, thereby creating a mess.
2310    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2311    space and tab.
2313    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2314    its new features into the main test script, reducing the number of scripts.
2316    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2317    were backward compatible, and made the (?i) apply to the whole pattern, as if
2318    /i were given. Now it behaves more logically, and applies the option setting
2319    only to what follows. PCRE has been changed to follow suit. However, if it
2320    finds options settings right at the start of the pattern, it extracts them into
2321    the global options, as before. Thus, they show up in the info data.
2323    8. Added support for the \Q...\E escape sequence. Characters in between are
2324    treated as literals. This is slightly different from Perl in that $ and @ are
2325    also handled as literals inside the quotes. In Perl, they will cause variable
2326    interpolation. Note the following examples:
2328        Pattern            PCRE matches      Perl matches
2330        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2331        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2332        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2334    For compatibility with Perl, \Q...\E sequences are recognized inside character
2335    classes as well as outside them.
2337    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2338    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2339    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2340    signed/unsigned warnings.
2342    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2343    option for pcretest, so I've replaced it by a simple function that does just
2344    that job.
2346    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2347    "pcregrep -".
2349    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2350    Java package. This provides some syntactic sugar for simple cases of what my
2351    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2352    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2353    item, you can use this simplified notation. Note that only makes sense with
2354    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2355    greediness, whatever the setting of the PCRE_UNGREEDY option.
2357    13. A change of greediness default within a pattern was not taking effect at
2358    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2359    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2360    was abstracted outside.
2362    14. PCRE now supports the \G assertion. It is true when the current matching
2363    position is at the start point of the match. This differs from \A when the
2364    starting offset is non-zero. Used with the /g option of pcretest (or similar
2365    code), it works in the same way as it does for Perl's /g option. If all
2366    alternatives of a regex begin with \G, the expression is anchored to the start
2367    match position, and the "anchored" flag is set in the compiled expression.
2369    15. Some bugs concerning the handling of certain option changes within patterns
2370    have been fixed. These applied to options other than (?ims). For example,
2371    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2372    been the other way round. Some of this was related to change 7 above.
2374    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2375    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2376    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2377    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2379    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2380    mode. Unlike ".", it always matches newline, whatever the setting of
2381    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2382    assertions. Perl allows it, but it doesn't (in general) work because it can't
2383    calculate the length of the lookbehind. At least, that's the case for Perl
2384    5.8.0 - I've been told they are going to document that it doesn't work in
2385    future.
2387    18. Added an error diagnosis for escapes that PCRE does not support: these are
2388    \L, \l, \N, \P, \p, \U, \u, and \X.
2390    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2391    reading past the end of the pattern in cases such as /[abcd/.
2393    20. PCRE was getting more memory than necessary for patterns with classes that
2394    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2396    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2397    compiling PCRE for use with Virtual Pascal.
2399    22. Small fix to the Makefile to make it work properly if the build is done
2400    outside the source tree.
2402    23. Added a new extension: a condition to go with recursion. If a conditional
2403    subpattern starts with (?(R) the "true" branch is used if recursion has
2404    happened, whereas the "false" branch is used only at the top level.
2406    24. When there was a very long string of literal characters (over 255 bytes
2407    without UTF support, over 250 bytes with UTF support), the computation of how
2408    much memory was required could be incorrect, leading to segfaults or other
2409    strange effects.
2411    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2412    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2413    there was a subsequent back reference to those brackets. This meant that, for
2414    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2415    possible to check for precisely this case. All we can do is abandon the
2416    optimization if .* occurs inside capturing brackets when there are any back
2417    references whatsoever. (See below for a better fix that came later.)
2419    26. The handling of the optimization for finding the first character of a
2420    non-anchored pattern, and for finding a character that is required later in the
2421    match were failing in some cases. This didn't break the matching; it just
2422    failed to optimize when it could. The way this is done has been re-implemented.
2424    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2426    28. Added a new feature that provides some of the functionality that Perl
2427    provides with (?{...}). The facility is termed a "callout". The way it is done
2428    in PCRE is for the caller to provide an optional function, by setting
2429    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2430    global variable. By default it is unset, which disables all calling out. To get
2431    the function called, the regex must include (?C) at appropriate points. This
2432    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2433    This provides a means of identifying different callout points. When PCRE
2434    reaches such a point in the regex, if pcre_callout has been set, the external
2435    function is called. It is provided with data in a structure called
2436    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2437    matching continues; if it returns a non-zero value, the match at the current
2438    point fails. However, backtracking will occur if possible. [This was changed
2439    later and other features added - see item 49 below.]
2441    29. pcretest is upgraded to test the callout functionality. It provides a
2442    callout function that displays information. By default, it shows the start of
2443    the match and the current position in the text. There are some new data escapes
2444    to vary what happens:
2446        \C+         in addition, show current contents of captured substrings
2447        \C-         do not supply a callout function
2448        \C!n        return 1 when callout number n is reached
2449        \C!n!m      return 1 when callout number n is reached for the mth time
2451    30. If pcregrep was called with the -l option and just a single file name, it
2452    output "<stdin>" if a match was found, instead of the file name.
2454    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2455    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2456    pcre_exec(). This saves a malloc/free per call. The default value of
2457    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2458    when configuring.
2460    32. The default maximum size of a compiled pattern is 64K. There have been a
2461    few cases of people hitting this limit. The code now uses macros to handle the
2462    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2463    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2464    configuring. Tests 2 and 5 work only with 2-byte links because they output
2465    debugging information about compiled patterns.
2467    33. Internal code re-arrangements:
2469    (a) Moved the debugging function for printing out a compiled regex into
2470        its own source file (printint.c) and used #include to pull it into
2471        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2472        separate copies.
2474    (b) Defined the list of op-code names for debugging as a macro in
2475        internal.h so that it is next to the definition of the opcodes.
2477    (c) Defined a table of op-code lengths for simpler skipping along compiled
2478        code. This is again a macro in internal.h so that it is next to the
2479        definition of the opcodes.
2481    34. Added support for recursive calls to individual subpatterns, along the
2482    lines of Robin Houston's patch (but implemented somewhat differently).
2484    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2485    allow it to read and process whole directories in Win32. This code was
2486    contributed by Lionel Fourquaux; it has not been tested by me.
2488    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2489    used to name a group. Names consist of alphanumerics and underscores, and must
2490    be unique. Back references use the syntax (?P=name) and recursive calls use
2491    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2492    numbers. The function pcre_fullinfo() can be used after compilation to extract
2493    a name/number map. There are three relevant calls:
2495      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2496      PCRE_INFO_NAMECOUNT            yields the number of entries
2497      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2499    The map is a vector of fixed-size entries. The size of each entry depends on
2500    the length of the longest name used. The first two bytes of each entry are the
2501    group number, most significant byte first. There follows the corresponding
2502    name, zero terminated. The names are in alphabetical order.
2504    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2505    case instead of 255. Making it the same both with and without UTF-8 support
2506    means that the same test output works with both.
2508    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2509    calling malloc() with a zero argument.
2511    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2512    optimization. I've improved things by keeping a bitmap of backreferences with
2513    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2514    fact referenced, the optimization can be applied. It is unlikely that a
2515    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2516    the match to follow \n) will appear inside brackets with a number greater than
2517    31, but if it does, any back reference > 31 suppresses the optimization.
2519    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2520    of disabling numbered capturing parentheses. Any opening parenthesis that is
2521    not followed by ? behaves as if it were followed by ?: but named parentheses
2522    can still be used for capturing (and they will acquire numbers in the usual
2523    way).
2525    41. Redesigned the return codes from the match() function into yes/no/error so
2526    that errors can be passed back from deep inside the nested calls. A malloc
2527    failure while inside a recursive subpattern call now causes the
2528    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2530    42. It is now possible to set a limit on the number of times the match()
2531    function is called in a call to pcre_exec(). This facility makes it possible to
2532    limit the amount of recursion and backtracking, though not in a directly
2533    obvious way, because the match() function is used in a number of different
2534    circumstances. The count starts from zero for each position in the subject
2535    string (for non-anchored patterns). The default limit is, for compatibility, a
2536    large number, namely 10 000 000. You can change this in two ways:
2538    (a) When configuring PCRE before making, you can use --with-match-limit=n
2539        to set a default value for the compiled library.
2541    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2542        a different value is set. See 45 below.
2544    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2546    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2547    of things that can be changed at compile time. The first argument specifies
2548    what is wanted and the second points to where the information is to be placed.
2549    The current list of available information is:
2551      PCRE_CONFIG_UTF8
2553    The output is an integer that is set to one if UTF-8 support is available;
2554    otherwise it is set to zero.
2558    The output is an integer that it set to the value of the code that is used for
2559    newline. It is either LF (10) or CR (13).
2563    The output is an integer that contains the number of bytes used for internal
2564    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2568    The output is an integer that contains the threshold above which the POSIX
2569    interface uses malloc() for output vectors. See item 31 above.
2573    The output is an unsigned integer that contains the default limit of the number
2574    of match() calls in a pcre_exec() execution. See 42 above.
2576    44. pcretest has been upgraded by the addition of the -C option. This causes it
2577    to extract all the available output from the new pcre_config() function, and to
2578    output it. The program then exits immediately.
2580    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2581    order to support additional features. One way would have been to define
2582    pcre_exec2() (for example) with extra arguments, but this would not have been
2583    extensible, and would also have required all calls to the original function to
2584    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2585    is used for passing in "extra" data from pcre_study().
2587    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2588    contains the following fields:
2590      flags         a bitmap indicating which of the following fields are set
2591      study_data    opaque data from pcre_study()
2592      match_limit   a way of specifying a limit on match() calls for a specific
2593                      call to pcre_exec()
2594      callout_data  data for callouts (see 49 below)
2596    The flag bits are also defined in pcre.h, and are
2602    The pcre_study() function now returns one of these new pcre_extra blocks, with
2603    the actual study data pointed to by the study_data field, and the
2604    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2605    before. That is, this change is entirely upwards-compatible and requires no
2606    change to existing code.
2608    If you want to pass in additional data to pcre_exec(), you can either place it
2609    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2610    block.
2612    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2613    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2614    times with different match limits, until it finds the minimum value needed for
2615    pcre_exec() to complete. The value is then output. This can be instructive; for
2616    most simple matches the number is quite small, but for pathological cases it
2617    gets very large very quickly.
2619    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2620    returns the size of the data block pointed to by the study_data field in a
2621    pcre_extra block, that is, the value that was passed as the argument to
2622    pcre_malloc() when PCRE was getting memory in which to place the information
2623    created by pcre_study(). The fourth argument should point to a size_t variable.
2624    pcretest has been extended so that this information is shown after a successful
2625    pcre_study() call when information about the compiled regex is being displayed.
2627    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2628    because what follows is always an absolute path. (Later: it turns out that this
2629    is more than cosmetic for MinGW, because it doesn't like empty path
2630    components.)
2632    49. Some changes have been made to the callout feature (see 28 above):
2634    (i)  A callout function now has three choices for what it returns:
2636           0  =>  success, carry on matching
2637         > 0  =>  failure at this point, but backtrack if possible
2638         < 0  =>  serious error, return this value from pcre_exec()
2640         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2641         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2642         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2643         use by callout functions. It will never be used by PCRE itself.
2645    (ii) The pcre_extra structure (see 45 above) has a void * field called
2646         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2647         pcre_callout_block structure has a field of the same name. The contents of
2648         the field passed in the pcre_extra structure are passed to the callout
2649         function in the corresponding field in the callout block. This makes it
2650         easier to use the same callout-containing regex from multiple threads. For
2651         testing, the pcretest program has a new data escape
2653           \C*n        pass the number n (may be negative) as callout_data
2655         If the callout function in pcretest receives a non-zero value as
2656         callout_data, it returns that value.
2658    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2659    there were some redundant $(CFLAGS) in commands that are now specified as
2660    $(LINK), which already includes $(CFLAGS).
2662    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2663    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2664    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2665    one-byte characters throughout. Note that case-insensitive matching applies
2666    only to characters whose values are less than 256. PCRE doesn't support the
2667    notion of cases for higher-valued characters.
2669    (i)   A character class whose characters are all within 0-255 is handled as
2670          a bit map, and the map is inverted for negative classes. Previously, a
2671          character > 255 always failed to match such a class; however it should
2672          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2674    (ii)  A negated character class with a single character < 255 is coded as
2675          "not this character" (OP_NOT). This wasn't working properly when the test
2676          character was multibyte, either singly or repeated.
2678    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2679          mode, for example: \x{100}{2,3}.
2681    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2682          singly or repeated) now correctly test multibyte characters. However,
2683          PCRE doesn't recognize any characters with values greater than 255 as
2684          digits, spaces, or word characters. Such characters always match \D, \S,
2685          and \W, and never match \d, \s, or \w.
2687    (v)   Classes may now contain characters and character ranges with values
2688          greater than 255. For example: [ab\x{100}-\x{400}].
2690    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2691          PCRE in UTF-8 mode.
2693    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2694    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2695    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2696    value.)
2698    53. The single man page has become too large. I have therefore split it up into
2699    a number of separate man pages. These also give rise to individual HTML pages;
2700    these are now put in a separate directory, and there is an index.html page that
2701    lists them all. Some hyperlinking between the pages has been installed.
2703    54. Added convenience functions for handling named capturing parentheses.
2705    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2706    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2707    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2708    are faulted.
2710    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2711    calling configure. These values are used when compiling the dftables.c program
2712    which is run to generate the source of the default character tables. They
2713    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2714    you will need to set these values.
2716    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2719    Version 3.9 02-Jan-02
2720    ---------------------
2722    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2724    2. If --disable-static was given, the building process failed when trying to
2725    build pcretest and pcregrep. (For some reason it was using libtool to compile
2726    them, which is not right, as they aren't part of the library.)
2729    Version 3.8 18-Dec-01
2730    ---------------------
2732    1. The experimental UTF-8 code was completely screwed up. It was packing the
2733    bytes in the wrong order. How dumb can you get?
2736    Version 3.7 29-Oct-01
2737    ---------------------
2739    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2740    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2741    this didn't happen under Solaris 8, where I normally test things.
2743    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2744    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2745    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2746    this fix an hour or so after the initial 3.7 release.)
2749    Version 3.6 23-Oct-01
2750    ---------------------
2752    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2753    offsets passed as NULL with zero offset count.
2755    2. The config.guess and config.sub files had not been updated when I moved to
2756    the latest autoconf.
2759    Version 3.5 15-Aug-01
2760    ---------------------
2762    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2763    had been forgotten.
2765    2. By using declared but undefined structures, we can avoid using "void"
2766    definitions in pcre.h while keeping the internal definitions of the structures
2767    private.
2769    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2770    user point of view, this means that both static and shared libraries are built
2771    by default, but this can be individually controlled. More of the work of
2772    handling this static/shared cases is now inside libtool instead of PCRE's make
2773    file.
2775    4. The pcretest utility is now installed along with pcregrep because it is
2776    useful for users (to test regexs) and by doing this, it automatically gets
2777    relinked by libtool. The documentation has been turned into a man page, so
2778    there are now .1, .txt, and .html versions in /doc.
2780    5. Upgrades to pcregrep:
2781       (i)   Added long-form option names like gnu grep.
2782       (ii)  Added --help to list all options with an explanatory phrase.
2783       (iii) Added -r, --recursive to recurse into sub-directories.
2784       (iv)  Added -f, --file to read patterns from a file.
2786    6. pcre_exec() was referring to its "code" argument before testing that
2787    argument for NULL (and giving an error if it was NULL).
2789    7. Upgraded Makefile.in to allow for compiling in a different directory from
2790    the source directory.
2792    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2793    options bits, the pointer it was passed was to an int instead of to an unsigned
2794    long int. This mattered only on 64-bit systems.
2796    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2797    generated) instead of pcre.in, which it its source. Also made the same change
2798    in several of the .c files.
2800    10. A new release of gcc defines printf() as a macro, which broke pcretest
2801    because it had an ifdef in the middle of a string argument for printf(). Fixed
2802    by using separate calls to printf().
2804    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2805    script, to force use of CR or LF instead of \n in the source. On non-Unix
2806    systems, the value can be set in config.h.
2808    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2809    absolute limit. Changed the text of the error message to make this clear, and
2810    likewise updated the man page.
2812    13. The limit of 99 on the number of capturing subpatterns has been removed.
2813    The new limit is 65535, which I hope will not be a "real" limit.
2816    Version 3.4 22-Aug-00
2817    ---------------------
2819    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2821    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2824    Version 3.3 01-Aug-00
2825    ---------------------
2827    1. If an octal character was given, but the value was greater than \377, it
2828    was not getting masked to the least significant bits, as documented. This could
2829    lead to crashes in some systems.
2831    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2832    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2834    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2835    These just pass their arguments on to (pcre_free)(), but they are provided
2836    because some uses of PCRE bind it to non-C systems that can call its functions,
2837    but cannot call free() or pcre_free() directly.
2839    4. Add "make test" as a synonym for "make check". Corrected some comments in
2840    the Makefile.
2842    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2843    Makefile.
2845    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2846    command called pgrep for grepping around the active processes.
2848    7. Added the beginnings of support for UTF-8 character strings.
2850    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2851    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2852    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2853    out for the ar command.)
2856    Version 3.2 12-May-00
2857    ---------------------
2859    This is purely a bug fixing release.
2861    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2862    of ZA. This was just one example of several cases that could provoke this bug,
2863    which was introduced by change 9 of version 2.00. The code for breaking
2864    infinite loops after an iteration that matches an empty string was't working
2865    correctly.
2867    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2868    when matched against abbab (for example). After matching an empty string, it
2869    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2870    caused it to match further down the string than it should.
2872    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2873    was there because it doesn't seem to be needed, and it causes trouble on some
2874    systems, as it is not a Standard C header. It has been removed.
2876    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2877    were reported on the Macintosh. The changes were from
2879      while ((c = *(++ptr)) != 0 && c != '\n');
2880    to
2881      while ((c = *(++ptr)) != 0 && c != '\n') ;
2883    Totally extraordinary, but if that's what it takes...
2885    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2886    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2887    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2888    assumes the way PCRE uses memmove() (always moving upwards).
2890    6. PCRE is being used in one environment where strchr() is not available. There
2891    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2892    faster code anyway.
2895    Version 3.1 09-Feb-00
2896    ---------------------
2898    The only change in this release is the fixing of some bugs in Makefile.in for
2899    the "install" target:
2901    (1) It was failing to install pcreposix.h.
2903    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2906    Version 3.0 01-Feb-00
2907    ---------------------
2909    1. Add support for the /+ modifier to perltest (to output $` like it does in
2910    pcretest).
2912    2. Add support for the /g modifier to perltest.
2914    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2915    matches null strings.
2917    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2918    pattern. Perl treats empty patterns specially - it reuses the most recent
2919    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2920    effect.
2922    5. The POSIX interface was broken in that it was just handing over the POSIX
2923    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2924    required a bigger vector, with some working space on the end. This means that
2925    the POSIX wrapper now has to get and free some memory, and copy the results.
2927    6. Added some simple autoconf support, placing the test data and the
2928    documentation in separate directories, re-organizing some of the
2929    information files, and making it build pcre-config (a GNU standard). Also added
2930    libtool support for building PCRE as a shared library, which is now the
2931    default.
2933    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2934    09 are not valid octal constants. Single digits will be used for minor values
2935    less than 10.
2937    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2938    existing programs that set these in the POSIX interface can use PCRE without
2939    modification.
2941    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2942    return all that pcre_info() returns, plus additional data. The pcre_info()
2943    function is retained for compatibility, but is considered to be obsolete.
2945    10. Added experimental recursion feature (?R) to handle one common case that
2946    Perl 5.6 will be able to do with (?p{...}).
2948    11. Added support for POSIX character classes like [:alpha:], which Perl is
2949    adopting.
2952    Version 2.08 31-Aug-99
2953    ----------------------
2955    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2956    trying to match at the startoffset position, but instead was moving forward to
2957    the next newline as if a previous match had failed.
2959    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2960    and could get into a loop if a null string was matched other than at the start
2961    of the subject.
2963    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2964    be distinguished at compile time, and for completeness also added PCRE_DATE.
2966    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2967    in GnuWin32 environments.
2970    Version 2.07 29-Jul-99
2971    ----------------------
2973    1. The documentation is now supplied in plain text form and HTML as well as in
2974    the form of man page sources.
2976    2. C++ compilers don't like assigning (void *) values to other pointer types.
2977    In particular this affects malloc(). Although there is no problem in Standard
2978    C, I've put in casts to keep C++ compilers happy.
2980    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2981    should be (const char *).
2983    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2984    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2985    However, I haven't made this a standard facility. The documentation doesn't
2986    mention it, and the Makefile doesn't support it.
2988    5. The Makefile now contains an "install" target, with editable destinations at
2989    the top of the file. The pcretest program is not installed.
2991    6. pgrep -V now gives the PCRE version number and date.
2993    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2994    causing the entire string to be ignored, instead of just the last character.
2996    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2997    non-matching string, it can take a very, very long time, even for strings of
2998    quite modest length, because of the nested recursion. PCRE now does better in
2999    some of these cases. It does this by remembering the last required literal
3000    character in the pattern, and pre-searching the subject to ensure it is present
3001    before running the real match. In other words, it applies a heuristic to detect
3002    some types of certain failure quickly, and in the above example, if presented
3003    with a string that has no trailing " it gives "no match" very quickly.
3005    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3006    other alternatives are tried instead.
3009    Version 2.06 09-Jun-99
3010    ----------------------
3012    1. Change pcretest's output for amount of store used to show just the code
3013    space, because the remainder (the data block) varies in size between 32-bit and
3014    64-bit systems.
3016    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3017    start matching at. This allows lookbehinds to work when searching for multiple
3018    occurrences in a string.
3020    3. Added additional options to pcretest for testing multiple occurrences:
3022       /+   outputs the rest of the string that follows a match
3023       /g   loops for multiple occurrences, using the new startoffset argument
3024       /G   loops for multiple occurrences by passing an incremented pointer
3026    4. PCRE wasn't doing the "first character" optimization for patterns starting
3027    with \b or \B, though it was doing it for other lookbehind assertions. That is,
3028    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3029    the letter 'x'. On long subject strings, this gives a significant speed-up.
3032    Version 2.05 21-Apr-99
3033    ----------------------
3035    1. Changed the type of magic_number from int to long int so that it works
3036    properly on 16-bit systems.
3038    2. Fixed a bug which caused patterns starting with .* not to work correctly
3039    when the subject string contained newline characters. PCRE was assuming
3040    anchoring for such patterns in all cases, which is not correct because .* will
3041    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3042    DOTALL is set at top level; otherwise it knows that patterns starting with .*
3043    must be retried after every newline in the subject.
3046    Version 2.04 18-Feb-99
3047    ----------------------
3049    1. For parenthesized subpatterns with repeats whose minimum was zero, the
3050    computation of the store needed to hold the pattern was incorrect (too large).
3051    If such patterns were nested a few deep, this could multiply and become a real
3052    problem.
3054    2. Added /M option to pcretest to show the memory requirement of a specific
3055    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3057    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3058    compiled in such a way that the backtracking after subsequent failure was
3059    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3060    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3063    Version 2.03 02-Feb-99
3064    ----------------------
3066    1. Fixed typo and small mistake in man page.
3068    2. Added 4th condition (GPL supersedes if conflict) and created separate
3069    LICENCE file containing the conditions.
3071    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3072    Perl, that is the internal \ allows the delimiter to be included in the
3073    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3074    the final delimiter, add \ to the end of the pattern (to test the error).
3076    4. Added the convenience functions for extracting substrings after a successful
3077    match. Updated pcretest to make it able to test these functions.
3080    Version 2.02 14-Jan-99
3081    ----------------------
3083    1. Initialized the working variables associated with each extraction so that
3084    their saving and restoring doesn't refer to uninitialized store.
3086    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3087    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3088    fix the problem.
3090    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3091    calls, and wasn't printing the correct value for compiling calls. Increased the
3092    default value of LOOPREPEAT, and the number of significant figures in the
3093    times.
3095    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3097    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3098    a building problem on Windows NT with a FAT file system.
3101    Version 2.01 21-Oct-98
3102    ----------------------
3104    1. Changed the API for pcre_compile() to allow for the provision of a pointer
3105    to character tables built by pcre_maketables() in the current locale. If NULL
3106    is passed, the default tables are used.
3109    Version 2.00 24-Sep-98
3110    ----------------------
3112    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3113    it any more.
3115    2. Allow quantification of (?>) groups, and make it work correctly.
3117    3. The first character computation wasn't working for (?>) groups.
3119    4. Correct the implementation of \Z (it is permitted to match on the \n at the
3120    end of the subject) and add 5.005's \z, which really does match only at the
3121    very end of the subject.
3123    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3125    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3126    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3127    localized options. All options to pcre_study() were also removed.
3129    7. Add other new features from 5.005:
3131       $(?<=           positive lookbehind
3132       $(?<!           negative lookbehind
3133       (?imsx-imsx)    added the unsetting capability
3134                       such a setting is global if at outer level; local otherwise
3135       (?imsx-imsx:)   non-capturing groups with option setting
3136       (?(cond)re|re)  conditional pattern matching
3138       A backreference to itself in a repeated group matches the previous
3139       captured string.
3141    8. General tidying up of studying (both automatic and via "study")
3142    consequential on the addition of new assertions.
3144    9. As in 5.005, unlimited repeated groups that could match an empty substring
3145    are no longer faulted at compile time. Instead, the loop is forcibly broken at
3146    runtime if any iteration does actually match an empty substring.
3148    10. Include the RunTest script in the distribution.
3150    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3151    discrepancies, some of which were old and were also with respect to 5.004. They
3152    have now been fixed.
3155    Version 1.09 28-Apr-98
3156    ----------------------
3158    1. A negated single character class followed by a quantifier with a minimum
3159    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
3160    program crashes, or just wrong answers. This did not apply to negated classes
3161    containing more than one character, or to minima other than one.
3164    Version 1.08 27-Mar-98
3165    ----------------------
3167    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3169    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3170    latter must appear before anything that relies on it in the pattern.
3173    Version 1.07 16-Feb-98
3174    ----------------------
3176    1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3177    repeat of a potentially empty string).
3180    Version 1.06 23-Jan-98
3181    ----------------------
3183    1. Added Markus Oberhumer's little patches for C++.
3185    2. Literal strings longer than 255 characters were broken.
3188    Version 1.05 23-Dec-97
3189    ----------------------
3191    1. Negated character classes containing more than one character were failing if
3192    PCRE_CASELESS was set at run time.
3195    Version 1.04 19-Dec-97
3196    ----------------------
3198    1. Corrected the man page, where some "const" qualifiers had been omitted.
3200    2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3201    input syntax.
3203    3. Fixed memory leak which occurred when a regex with back references was
3204    matched with an offsets vector that wasn't big enough. The temporary memory
3205    that is used in this case wasn't being freed if the match failed.
3207    4. Tidied pcretest to ensure it frees memory that it gets.
3209    5. Temporary memory was being obtained in the case where the passed offsets
3210    vector was exactly big enough.
3212    6. Corrected definition of offsetof() from change 5 below.
3214    7. I had screwed up change 6 below and broken the rules for the use of
3215    setjmp(). Now fixed.
3218  Version 1.03 18-Dec-97  Version 1.03 18-Dec-97
3219  ----------------------  ----------------------
# Line 39  optimized code for single-character nega Line 3252  optimized code for single-character nega
3252  from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.  from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3254  7. Constructs such as \d{8,} were compiling into the equivalent of  7. Constructs such as \d{8,} were compiling into the equivalent of
3255  \d{8}\d{65527} instead of \d{8}\d* which didn't make much difference to the  \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3256  outcome, but in this particular case used more store than had been allocated,  outcome, but in this particular case used more store than had been allocated,
3257  which caused the bug to be discovered because it threw up an internal error.  which caused the bug to be discovered because it threw up an internal error.

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