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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 419 by ph10, Wed Aug 12 10:45:33 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.00 ??-???-??
5    ----------------------
7    1.  The table for translating pcre_compile() error codes into POSIX error codes
8        was out-of-date, and there was no check on the pcre_compile() error code
9        being within the table. This could lead to an OK return being given in
10        error.
12    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
13        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
14        in a Windows environment.
17    Version 7.9 11-Apr-09
18    ---------------------
20    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
21        (pcretest), all targets were linked against these libraries. This included
22        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
23        libraries. This caused unwanted dependencies to be created. This problem
24        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
25        pcretest is linked with readline.
27    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
28        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
29        moved outside it again, because FALSE and TRUE are already defined in AIX,
30        but BOOL is not.
32    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
33        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
35    4.  The pcregrep documentation said spaces were inserted as well as colons (or
36        hyphens) following file names and line numbers when outputting matching
37        lines. This is not true; no spaces are inserted. I have also clarified the
38        wording for the --colour (or --color) option.
40    5.  In pcregrep, when --colour was used with -o, the list of matching strings
41        was not coloured; this is different to GNU grep, so I have changed it to be
42        the same.
44    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
45        each matching line was coloured. Now it goes on to look for further matches
46        of any of the test patterns, which is the same behaviour as GNU grep.
48    7.  A pattern that could match an empty string could cause pcregrep to loop; it
49        doesn't make sense to accept an empty string match in pcregrep, so I have
50        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
51        seems to be how GNU grep behaves.
53    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
54        start or after a newline", because the conditional assertion was not being
55        correctly handled. The rule now is that both the assertion and what follows
56        in the first alternative must satisfy the test.
58    9.  If auto-callout was enabled in a pattern with a conditional group whose
59        condition was an assertion, PCRE could crash during matching, both with
60        pcre_exec() and pcre_dfa_exec().
62    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
63        used for matching.
65    11. Unicode property support in character classes was not working for
66        characters (bytes) greater than 127 when not in UTF-8 mode.
68    12. Added the -M command line option to pcretest.
70    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
72    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
74    16. Added comments and documentation about mis-use of no_arg in the C++
75        wrapper.
77    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
78        from Martin Jerabek that uses macro names for all relevant character and
79        string constants.
81    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
82        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
83        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
84        these, but not everybody uses configure.
86    19. A conditional group that had only one branch was not being correctly
87        recognized as an item that could match an empty string. This meant that an
88        enclosing group might also not be so recognized, causing infinite looping
89        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
90        with the subject "ab", where knowledge that the repeated group can match
91        nothing is needed in order to break the loop.
93    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
94        exec(), but without supplying a callout function, matching went wrong.
96    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
97        leak if the size of the offset vector was greater than 30. When the vector
98        is smaller, the saved offsets during recursion go onto a local stack
99        vector, but for larger vectors malloc() is used. It was failing to free
100        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
101        error, in fact).
103    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
104        heapframe that is used only when UTF-8 support is enabled. This caused no
105        problem, but was untidy.
107    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
108        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
109        included within another project.
111    24. Steven Van Ingelgem's patches to add more options to the CMake support,
112        slightly modified by me:
114          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
115              not building pcregrep.
117          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
118              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
120    25. Forward references, both numeric and by name, in patterns that made use of
121        duplicate group numbers, could behave incorrectly or give incorrect errors,
122        because when scanning forward to find the reference group, PCRE was not
123        taking into account the duplicate group numbers. A pattern such as
124        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
126    26. Changed a few more instances of "const unsigned char *" to USPTR, making
127        the feature of a custom pointer more persuasive (as requested by a user).
129    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
130        pcretest.c, inside #ifndefs, because it seems they are sometimes already
131        pre-defined.
133    28. Added support for (*UTF8) at the start of a pattern.
135    29. Arrange for flags added by the "release type" setting in CMake to be shown
136        in the configuration summary.
139    Version 7.8 05-Sep-08
140    ---------------------
142    1.  Replaced UCP searching code with optimized version as implemented for Ad
143        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
144        stage table and inline lookup instead of a function, giving speed ups of 2
145        to 5 times on some simple patterns that I tested. Permission was given to
146        distribute the MultiStage2.py script that generates the tables (it's not in
147        the tarball, but is in the Subversion repository).
149    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
150        scripts.
152    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
153        a group with a zero qualifier. The result of the study could be incorrect,
154        or the function might crash, depending on the pattern.
156    4.  Caseless matching was not working for non-ASCII characters in back
157        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
158        It now works when Unicode Property Support is available.
160    5.  In pcretest, an escape such as \x{de} in the data was always generating
161        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
162        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
163        truncation.
165    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
167    7.  Added two (int) casts to pcregrep when printing the difference of two
168        pointers, in case they are 64-bit values.
170    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
171        test 2 if it fails.
173    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
174        and a #define of that name to empty if it is not externally set. This is to
175        allow users of MSVC to set it if necessary.
177    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
178        the convenience functions in the pcre_get.c source file.
180    11. An option change at the start of a pattern that had top-level alternatives
181        could cause overwriting and/or a crash. This command provoked a crash in
182        some environments:
184          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
186        This potential security problem was recorded as CVE-2008-2371.
188    12. For a pattern where the match had to start at the beginning or immediately
189        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
190        pcre_dfa_exec() could read past the end of the passed subject if there was
191        no match. To help with detecting such bugs (e.g. with valgrind), I modified
192        pcretest so that it places the subject at the end of its malloc-ed buffer.
194    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
195        exec() might read past the end of the data buffer in UTF-8 mode.
197    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
198        the data contained the byte 0x85 as part of a UTF-8 character within its
199        first line. This applied both to normal and DFA matching.
201    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
202        /^[^d]*?$/8 failed to match "abc".
204    16. Added a missing copyright notice to pcrecpp_internal.h.
206    17. Make it more clear in the documentation that values returned from
207        pcre_exec() in ovector are byte offsets, not character counts.
209    18. Tidied a few places to stop certain compilers from issuing warnings.
211    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
212        supplied by Stefan Weber. I made a further small update for 7.8 because
213        there is a change of source arrangements: the pcre_searchfuncs.c module is
214        replaced by pcre_ucd.c.
217    Version 7.7 07-May-08
218    ---------------------
220    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
221        a string to a long long, pretend we don't even have a long long." This is
222        done by checking for the strtoq, strtoll, and _strtoi64 functions.
224    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
225        pre-7.6 versions, which defined a global no_arg variable instead of putting
226        it in the RE class. (See also #8 below.)
228    3.  Remove a line of dead code, identified by coverity and reported by Nuno
229        Lopes.
231    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
233        (1) The include/exclude patterns were being applied to the whole pathnames
234            of files, instead of just to the final components.
236        (2) If there was more than one level of directory, the subdirectories were
237            skipped unless they satisfied the include/exclude conditions. This is
238            inconsistent with GNU grep (and could even be seen as contrary to the
239            pcregrep specification - which I improved to make it absolutely clear).
240            The action now is always to scan all levels of directory, and just
241            apply the include/exclude patterns to regular files.
243    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
244        --exclude_dir in the tests to avoid scanning .svn directories.
246    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
247        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
248        doesn't support NULs in patterns.
250    7.  Added some missing "const"s to declarations of static tables in
251        pcre_compile.c and pcre_dfa_exec.c.
253    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
254        caused by fix #2  above. (Subsequently also a second patch to fix the
255        first patch. And a third patch - this was a messy problem.)
257    9.  Applied Craig's patch to remove the use of push_back().
259    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
260        matching function regexec().
262    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
263        which, however, unlike Perl's \g{...}, are subroutine calls, not back
264        references. PCRE supports relative numbers with this syntax (I don't think
265        Oniguruma does).
267    12. Previously, a group with a zero repeat such as (...){0} was completely
268        omitted from the compiled regex. However, this means that if the group
269        was called as a subroutine from elsewhere in the pattern, things went wrong
270        (an internal error was given). Such groups are now left in the compiled
271        pattern, with a new opcode that causes them to be skipped at execution
272        time.
274    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
275        to the way PCRE behaves:
277        (a) A lone ] character is dis-allowed (Perl treats it as data).
279        (b) A back reference to an unmatched subpattern matches an empty string
280            (Perl fails the current match path).
282        (c) A data ] in a character class must be notated as \] because if the
283            first data character in a class is ], it defines an empty class. (In
284            Perl it is not possible to have an empty class.) The empty class []
285            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
286            The negative empty class [^] matches any one character, independently
287            of the DOTALL setting.
289    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
290        non-existent subpattern following a character class starting with ']' and
291        containing () gave an internal compiling error instead of "reference to
292        non-existent subpattern". Fortunately, when the pattern did exist, the
293        compiled code was correct. (When scanning forwards to check for the
294        existencd of the subpattern, it was treating the data ']' as terminating
295        the class, so got the count wrong. When actually compiling, the reference
296        was subsequently set up correctly.)
298    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
299        it was being rejected as not supported by pcre_dfa_exec(), even though
300        other assertions are supported. I have made pcre_dfa_exec() support
301        (*FAIL).
303    16. The implementation of 13c above involved the invention of a new opcode,
304        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
305        cannot be changed at match time, I realized I could make a small
306        improvement to matching performance by compiling OP_ALLANY instead of
307        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
308        on the OP_ANY path.
310    17. Compiling pcretest on Windows with readline support failed without the
311        following two fixes: (1) Make the unistd.h include conditional on
312        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
314    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
315        ncurses library to be included for pcretest when ReadLine support is
316        requested, but also to allow for it to be overridden. This patch came from
317        Daniel Bergström.
319    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
320        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
321        any errors with the current Unicode tables. Thanks to Peter Kankowski for
322        spotting this.
325    Version 7.6 28-Jan-08
326    ---------------------
328    1.  A character class containing a very large number of characters with
329        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
330        overflow.
332    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
333        HAVE_LONG_LONG is not defined.
335    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
336        bring them up to date and include new features. This patch includes:
338        - Fixed PH's badly added libz and libbz2 support.
339        - Fixed a problem with static linking.
340        - Added pcredemo. [But later removed - see 7 below.]
341        - Fixed dftables problem and added an option.
342        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
343            HAVE_LONG_LONG.
344        - Added readline support for pcretest.
345        - Added an listing of the option settings after cmake has run.
347    4.  A user submitted a patch to Makefile that makes it easy to create
348        "pcre.dll" under mingw when using Configure/Make. I added stuff to
349        Makefile.am that cause it to include this special target, without
350        affecting anything else. Note that the same mingw target plus all
351        the other distribution libraries and programs are now supported
352        when configuring with CMake (see 6 below) instead of with
353        Configure/Make.
355    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
356        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
357        exported in the Windows port". It has not yet been confirmed that the patch
358        solves the problem, but it does no harm.
360    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
361        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
362        with CMake, and also correct the comment about stack recursion.
364    7.  Remove the automatic building of pcredemo from the ./configure system and
365        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
366        of a program that users should build themselves after PCRE is installed, so
367        building it automatically is not really right. What is more, it gave
368        trouble in some build environments.
370    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
373    Version 7.5 10-Jan-08
374    ---------------------
376    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
377        values in parens when parsing an RE using the C++ wrapper."
379    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
380        Characters greater than 255 were excluded from the class instead of being
381        included.
383    3.  The same bug as (2) above applied to negated POSIX classes such as
384        [:^space:].
386    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
387        defined or documented. It seems to have been a typo for PCRE_STATIC, so
388        I have changed it.
390    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
391        first named subpattern) and a construct such as (?&a) would reference the
392        first named subpattern whose name started with "a" (in other words, the
393        length check was missing). Both these problems are fixed. "Subpattern name
394        expected" is now given for (?&) (a zero-length name), and this patch also
395        makes it give the same error for \k'' (previously it complained that that
396        was a reference to a non-existent subpattern).
398    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
399        this is right because (?- can be followed by option settings as well as by
400        digits. I have, however, made the messages clearer.
402    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
403        than the number used in the conditional) now cause a compile-time error.
404        This is actually not compatible with Perl, which accepts such patterns, but
405        treats the conditional as always being FALSE (as PCRE used to), but it
406        seems to me that giving a diagnostic is better.
408    8.  Change "alphameric" to the more common word "alphanumeric" in comments
409        and messages.
411    9.  Fix two occurrences of "backslash" in comments that should have been
412        "backspace".
414    10. Remove two redundant lines of code that can never be obeyed (their function
415        was moved elsewhere).
417    11. The program that makes PCRE's Unicode character property table had a bug
418        which caused it to generate incorrect table entries for sequences of
419        characters that have the same character type, but are in different scripts.
420        It amalgamated them into a single range, with the script of the first of
421        them. In other words, some characters were in the wrong script. There were
422        thirteen such cases, affecting characters in the following ranges:
424          U+002b0 - U+002c1
425          U+0060c - U+0060d
426          U+0061e - U+00612
427          U+0064b - U+0065e
428          U+0074d - U+0076d
429          U+01800 - U+01805
430          U+01d00 - U+01d77
431          U+01d9b - U+01dbf
432          U+0200b - U+0200f
433          U+030fc - U+030fe
434          U+03260 - U+0327f
435          U+0fb46 - U+0fbb1
436          U+10450 - U+1049d
438    12. The -o option (show only the matching part of a line) for pcregrep was not
439        compatible with GNU grep in that, if there was more than one match in a
440        line, it showed only the first of them. It now behaves in the same way as
441        GNU grep.
443    13. If the -o and -v options were combined for pcregrep, it printed a blank
444        line for every non-matching line. GNU grep prints nothing, and pcregrep now
445        does the same. The return code can be used to tell if there were any
446        non-matching lines.
448    14. Added --file-offsets and --line-offsets to pcregrep.
450    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
451        infinitely looping recursion. The bug was that positive lookaheads were not
452        being skipped when checking for a possible empty match (negative lookaheads
453        and both kinds of lookbehind were skipped).
455    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
456        inclusion of <windows.h> to before rather than after the definition of
457        INVALID_FILE_ATTRIBUTES (patch from David Byron).
459    17. Specifying a possessive quantifier with a specific limit for a Unicode
460        character property caused pcre_compile() to compile bad code, which led at
461        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
462        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
463        caused the error; without that there was no problem.
465    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
467    19. Added --enable-pcretest-libreadline.
469    20. In pcrecpp.cc, the variable 'count' was incremented twice in
470        RE::GlobalReplace(). As a result, the number of replacements returned was
471        double what it should be. I removed one of the increments, but Craig sent a
472        later patch that removed the other one (the right fix) and added unit tests
473        that check the return values (which was not done before).
475    21. Several CMake things:
477        (1) Arranged that, when cmake is used on Unix, the libraries end up with
478            the names libpcre and libpcreposix, not just pcre and pcreposix.
480        (2) The above change means that pcretest and pcregrep are now correctly
481            linked with the newly-built libraries, not previously installed ones.
485    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
486        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
487        UTF-8 newline character). The key issue is that the pattern starts .*;
488        this means that the match must be either at the beginning, or after a
489        newline. The bug was in the code for advancing after a failed match and
490        checking that the new position followed a newline. It was not taking
491        account of UTF-8 characters correctly.
493    23. PCRE was behaving differently from Perl in the way it recognized POSIX
494        character classes. PCRE was not treating the sequence [:...:] as a
495        character class unless the ... were all letters. Perl, however, seems to
496        allow any characters between [: and :], though of course it rejects as
497        unknown any "names" that contain non-letters, because all the known class
498        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
499        for example, whereas PCRE did not - it did not recognize a POSIX character
500        class. This seemed a bit dangerous, so the code has been changed to be
501        closer to Perl. The behaviour is not identical to Perl, because PCRE will
502        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
503        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
504        Perl does, and where it didn't before.
506    24. Rewrite so as to remove the single use of %n from pcregrep because in some
507        Windows environments %n is disabled by default.
510    Version 7.4 21-Sep-07
511    ---------------------
513    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
514        means that a class such as [\s] counted as "explicit reference to CR or
515        LF". That isn't really right - the whole point of the change was to try to
516        help when there was an actual mention of one of the two characters. So now
517        the change happens only if \r or \n (or a literal CR or LF) character is
518        encountered.
520    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
521        of both had grown to the point where there were only 3 bits left.
522        Fortunately, there was spare space in the data structure, and so I have
523        moved the internal flags into a new 16-bit field to free up more option
524        bits.
526    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
527        but did not set the internal JCHANGED flag - either of these is enough to
528        control the way the "get" function works - but the PCRE_INFO_JCHANGED
529        facility is supposed to tell if (?J) was ever used, so now (?J) at the
530        start sets both bits.
532    4.  Added options (at build time, compile time, exec time) to change \R from
533        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
535    5.  doc/pcresyntax.html was missing from the distribution.
537    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
538        compatibility, even though it is no longer used.
540    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
541        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
542        windows.h file is present (where different names are used). [This was
543        reversed later after testing - see 16 below.]
545    8.  Changed all #include <config.h> to #include "config.h". There were also
546        some further <pcre.h> cases that I changed to "pcre.h".
548    9.  When pcregrep was used with the --colour option, it missed the line ending
549        sequence off the lines that it output.
551    10. It was pointed out to me that arrays of string pointers cause lots of
552        relocations when a shared library is dynamically loaded. A technique of
553        using a single long string with a table of offsets can drastically reduce
554        these. I have refactored PCRE in four places to do this. The result is
555        dramatic:
557          Originally:                          290
558          After changing UCP table:            187
559          After changing error message table:   43
560          After changing table of "verbs"       36
561          After changing table of Posix names   22
563        Thanks to the folks working on Gregex for glib for this insight.
565    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
566        unicode-properties was also set.
568    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
570    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
571        checked only for CRLF.
573    14. Added casts to pcretest.c to avoid compiler warnings.
575    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
577    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
578        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
579        entirely. This removes changes made in 7 above.
581    17. The CMake files have been updated, and there is now more information about
582        building with CMake in the NON-UNIX-USE document.
585    Version 7.3 28-Aug-07
586    ---------------------
588     1. In the rejigging of the build system that eventually resulted in 7.1, the
589        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
590        brackets there is not right, since it causes compilers to look for an
591        installed pcre.h, not the version that is in the source that is being
592        compiled (which of course may be different). I have changed it back to:
594          #include "pcre.h"
596        I have a vague recollection that the change was concerned with compiling in
597        different directories, but in the new build system, that is taken care of
598        by the VPATH setting the Makefile.
600     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
601        when the subject happened to end in the byte 0x85 (e.g. if the last
602        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
603        characters but of course it shouldn't be taken as a newline when it is part
604        of another character. The bug was that, for an unlimited repeat of . in
605        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
606        characters when looking for a newline.
608     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
610     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
611        in debug output.
613     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
614        long printing in the pcrecpp unittest when running under MinGW.
616     6. ESC_K was left out of the EBCDIC table.
618     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
619        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
620        limit also applies to "virtual nesting" when a pattern is recursive, and in
621        this case 1000 isn't so big. I have been able to remove this limit at the
622        expense of backing off one optimization in certain circumstances. Normally,
623        when pcre_exec() would call its internal match() function recursively and
624        immediately return the result unconditionally, it uses a "tail recursion"
625        feature to save stack. However, when a subpattern that can match an empty
626        string has an unlimited repetition quantifier, it no longer makes this
627        optimization. That gives it a stack frame in which to save the data for
628        checking that an empty string has been matched. Previously this was taken
629        from the 1000-entry workspace that had been reserved. So now there is no
630        explicit limit, but more stack is used.
632     8. Applied Daniel's patches to solve problems with the import/export magic
633        syntax that is required for Windows, and which was going wrong for the
634        pcreposix and pcrecpp parts of the library. These were overlooked when this
635        problem was solved for the main library.
637     9. There were some crude static tests to avoid integer overflow when computing
638        the size of patterns that contain repeated groups with explicit upper
639        limits. As the maximum quantifier is 65535, the maximum group length was
640        set at 30,000 so that the product of these two numbers did not overflow a
641        32-bit integer. However, it turns out that people want to use groups that
642        are longer than 30,000 bytes (though not repeat them that many times).
643        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
644        made it possible to implement the integer overflow checks in a much more
645        dynamic way, which I have now done. The artificial limitation on group
646        length has been removed - we now have only the limit on the total length of
647        the compiled pattern, which depends on the LINK_SIZE setting.
649    10. Fixed a bug in the documentation for get/copy named substring when
650        duplicate names are permitted. If none of the named substrings are set, the
651        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
652        empty string.
654    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
655        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
656        because the ] is interpreted as the first data character and the
657        terminating ] is not found. PCRE has been made compatible with Perl in this
658        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
659        cause memory overwriting.
661    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
662        string has been matched (to stop an infinite loop). It was not recognizing
663        a conditional subpattern that could match an empty string if that
664        subpattern was within another subpattern. For example, it looped when
665        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
666        condition was not nested. This bug has been fixed.
668    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
669        past the start of the subject in the presence of bytes with the top bit
670        set, for example "\x8aBCD".
672    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
673        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
675    14. Optimized (?!) to (*FAIL).
677    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
678        This restricts code points to be within the range 0 to 0x10FFFF, excluding
679        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
680        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
681        does: it's just the validity check that is more restrictive.
683    16. Inserted checks for integer overflows during escape sequence (backslash)
684        processing, and also fixed erroneous offset values for syntax errors during
685        backslash processing.
687    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
688        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
690    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
691        caused an overrun.
693    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
694        something other than just ASCII characters) inside a group that had an
695        unlimited repeat caused a loop at compile time (while checking to see
696        whether the group could match an empty string).
698    20. Debugging a pattern containing \p or \P could cause a crash. For example,
699        [\P{Any}] did so. (Error in the code for printing property names.)
701    21. An orphan \E inside a character class could cause a crash.
703    22. A repeated capturing bracket such as (A)? could cause a wild memory
704        reference during compilation.
706    23. There are several functions in pcre_compile() that scan along a compiled
707        expression for various reasons (e.g. to see if it's fixed length for look
708        behind). There were bugs in these functions when a repeated \p or \P was
709        present in the pattern. These operators have additional parameters compared
710        with \d, etc, and these were not being taken into account when moving along
711        the compiled data. Specifically:
713        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
714            length.
716        (b) An item such as \pL+ within a repeated group could cause crashes or
717            loops.
719        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
720            "reference to non-existent subpattern" error.
722        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
724    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
725        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
727    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
729    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
730        character were causing crashes (broken optimization).
732    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
733        \p or \P) caused a compile-time loop.
735    28. More problems have arisen in unanchored patterns when CRLF is a valid line
736        break. For example, the unstudied pattern [\r\n]A does not match the string
737        "\r\nA" because change 7.0/46 below moves the current point on by two
738        characters after failing to match at the start. However, the pattern \nA
739        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
740        the same is true. There doesn't seem any very clean way out of this, but
741        what I have chosen to do makes the common cases work: PCRE now takes note
742        of whether there can be an explicit match for \r or \n anywhere in the
743        pattern, and if so, 7.0/46 no longer applies. As part of this change,
744        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
745        pattern has explicit CR or LF references.
747    29. Added (*CR) etc for changing newline setting at start of pattern.
750    Version 7.2 19-Jun-07
751    ---------------------
753     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
754        which is apparently normally available under Windows.
756     2. Re-jig the pcregrep tests with different newline settings in an attempt
757        to make them independent of the local environment's newline setting.
759     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
761     4. Some of the "internals" tests were previously cut out when the link size
762        was not 2, because the output contained actual offsets. The recent new
763        "Z" feature of pcretest means that these can be cut out, making the tests
764        usable with all link sizes.
766     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
767        stack recursion. This gives a massive performance boost under BSD, but just
768        a small improvement under Linux. However, it saves one field in the frame
769        in all cases.
771     6. Added more features from the forthcoming Perl 5.10:
773        (a) (?-n) (where n is a string of digits) is a relative subroutine or
774            recursion call. It refers to the nth most recently opened parentheses.
776        (b) (?+n) is also a relative subroutine call; it refers to the nth next
777            to be opened parentheses.
779        (c) Conditions that refer to capturing parentheses can be specified
780            relatively, for example, (?(-2)... or (?(+3)...
782        (d) \K resets the start of the current match so that everything before
783            is not part of it.
785        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
787        (f) \g{name} is another synonym - part of Perl 5.10's unification of
788            reference syntax.
790        (g) (?| introduces a group in which the numbering of parentheses in each
791            alternative starts with the same number.
793        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
795     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
798     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
799        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
800        for detecting groups that can match an empty string.
802     9. A pattern with a very large number of alternatives (more than several
803        hundred) was running out of internal workspace during the pre-compile
804        phase, where pcre_compile() figures out how much memory will be needed. A
805        bit of new cunning has reduced the workspace needed for groups with
806        alternatives. The 1000-alternative test pattern now uses 12 bytes of
807        workspace instead of running out of the 4096 that are available.
809    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
811    11. Applied patch from Google to remove an optimization that didn't quite work.
812        The report of the bug said:
814          pcrecpp::RE("a*").FullMatch("aaa") matches, while
815          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
816          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
818    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
819        it matched the wrong number of bytes.
822    Version 7.1 24-Apr-07
823    ---------------------
825     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
826        that is more "standard", making use of automake and other Autotools. There
827        is some re-arrangement of the files and adjustment of comments consequent
828        on this.
830     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
831        for recursive directory scanning broke on some systems because the files
832        are not scanned in any specific order and on different systems the order
833        was different. A call to "sort" has been inserted into RunGrepTest for the
834        approprate test as a short-term fix. In the longer term there may be an
835        alternative.
837     3. I had an email from Eric Raymond about problems translating some of PCRE's
838        man pages to HTML (despite the fact that I distribute HTML pages, some
839        people do their own conversions for various reasons). The problems
840        concerned the use of low-level troff macros .br and .in. I have therefore
841        removed all such uses from the man pages (some were redundant, some could
842        be replaced by .nf/.fi pairs). The 132html script that I use to generate
843        HTML has been updated to handle .nf/.fi and to complain if it encounters
844        .br or .in.
846     4. Updated comments in configure.ac that get placed in config.h.in and also
847        arranged for config.h to be included in the distribution, with the name
848        config.h.generic, for the benefit of those who have to compile without
849        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
851     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
852        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
853        makevp.bat for the current PCRE, using the additional files
854        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
856     6. A Windows user reported a minor discrepancy with test 2, which turned out
857        to be caused by a trailing space on an input line that had got lost in his
858        copy. The trailing space was an accident, so I've just removed it.
860     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
861        that is needed.
863     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
864        as "const" (a) because they are and (b) because it helps the PHP
865        maintainers who have recently made a script to detect big data structures
866        in the php code that should be moved to the .rodata section. I remembered
867        to update Builducptable as well, so it won't revert if ucptable.h is ever
868        re-created.
870     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
871        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
872        order to be able to cut out the UTF-8 tables in the latter when UTF-8
873        support is not required. This saves 1.5-2K of code, which is important in
874        some applications.
876        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
877        so as not to refer to the tables, even though these functions will never be
878        called when UTF-8 support is disabled. Otherwise there are problems with a
879        shared library.
881    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
883        (a) It was defining its arguments as char * instead of void *.
885        (b) It was assuming that all moves were upwards in memory; this was true
886            a long time ago when I wrote it, but is no longer the case.
888        The emulated memove() is provided for those environments that have neither
889        memmove() nor bcopy(). I didn't think anyone used it these days, but that
890        is clearly not the case, as these two bugs were recently reported.
892    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
893        and Detrail to create the HTML documentation, the .txt form of the man
894        pages, and it removes trailing spaces from listed files. It also creates
895        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
896        case, it wraps all the #defines with #ifndefs. This script should be run
897        before "make dist".
899    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
900        with Unicode property support.
902        (a) For a maximizing quantifier, if the two different cases of the
903            character were of different lengths in their UTF-8 codings (there are
904            some cases like this - I found 11), and the matching function had to
905            back up over a mixture of the two cases, it incorrectly assumed they
906            were both the same length.
908        (b) When PCRE was configured to use the heap rather than the stack for
909            recursion during matching, it was not correctly preserving the data for
910            the other case of a UTF-8 character when checking ahead for a match
911            while processing a minimizing repeat. If the check also involved
912            matching a wide character, but failed, corruption could cause an
913            erroneous result when trying to check for a repeat of the original
914            character.
916    13. Some tidying changes to the testing mechanism:
918        (a) The RunTest script now detects the internal link size and whether there
919            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
920            values substituted by "configure". (The RunGrepTest script already did
921            this for UTF-8.) The configure.ac script no longer substitutes the
922            relevant variables.
924        (b) The debugging options /B and /D in pcretest show the compiled bytecode
925            with length and offset values. This means that the output is different
926            for different internal link sizes. Test 2 is skipped for link sizes
927            other than 2 because of this, bypassing the problem. Unfortunately,
928            there was also a test in test 3 (the locale tests) that used /B and
929            failed for link sizes other than 2. Rather than cut the whole test out,
930            I have added a new /Z option to pcretest that replaces the length and
931            offset values with spaces. This is now used to make test 3 independent
932            of link size. (Test 2 will be tidied up later.)
934    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
935        segmentation fault instead of returning the appropriate error message.
937    15. In multiline mode when the newline sequence was set to "any", the pattern
938        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
939        This doesn't seem right; it now treats the CRLF combination as the line
940        ending, and so does not match in that case. It's only a pattern such as ^$
941        that would hit this one: something like ^ABC$ would have failed after \r
942        and then tried again after \r\n.
944    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
945        in an attempt to make files that differ only in their line terminators
946        compare equal. This works on Linux.
948    17. Under certain error circumstances pcregrep might try to free random memory
949        as it exited. This is now fixed, thanks to valgrind.
951    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
952        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
953        was because its rules for how to advance for /g after matching an empty
954        string at the end of a line did not allow for this case. They now check for
955        it specially.
957    20. pcretest is supposed to handle patterns and data of any length, by
958        extending its buffers when necessary. It was getting this wrong when the
959        buffer for a data line had to be extended.
961    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
962        CRLF as a newline sequence.
964    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
965        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
966        I have nevertheless tidied it up.
968    23. Added some casts to kill warnings from HP-UX ia64 compiler.
970    24. Added a man page for pcre-config.
973    Version 7.0 19-Dec-06
974    ---------------------
976     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
977        moving to gcc 4.1.1.
979     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
980        sys/time.h, which is documented as needed for this function. It doesn't
981        seem to matter on Linux, but it showed up on some releases of OS X.
983     3. It seems that there are systems where bytes whose values are greater than
984        127 match isprint() in the "C" locale. The "C" locale should be the
985        default when a C program starts up. In most systems, only ASCII printing
986        characters match isprint(). This difference caused the output from pcretest
987        to vary, making some of the tests fail. I have changed pcretest so that:
989        (a) When it is outputting text in the compiled version of a pattern, bytes
990            other than 32-126 are always shown as hex escapes.
992        (b) When it is outputting text that is a matched part of a subject string,
993            it does the same, unless a different locale has been set for the match
994            (using the /L modifier). In this case, it uses isprint() to decide.
996     4. Fixed a major bug that caused incorrect computation of the amount of memory
997        required for a compiled pattern when options that changed within the
998        pattern affected the logic of the preliminary scan that determines the
999        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1000        that the computed length was too small. The symptoms of this bug were
1001        either the PCRE error "internal error: code overflow" from pcre_compile(),
1002        or a glibc crash with a message such as "pcretest: free(): invalid next
1003        size (fast)". Examples of patterns that provoked this bug (shown in
1004        pcretest format) are:
1006          /(?-x: )/x
1007          /(?x)(?-x: \s*#\s*)/
1008          /((?i)[\x{c0}])/8
1009          /(?i:[\x{c0}])/8
1011        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1012        is now done differently.
1014     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1015        wrapper classes; (b) implement a new function in the C++ scanner that is
1016        more efficient than the old way of doing things because it avoids levels of
1017        recursion in the regex matching; (c) add a paragraph to the documentation
1018        for the FullMatch() function.
1020     6. The escape sequence \n was being treated as whatever was defined as
1021        "newline". Not only was this contrary to the documentation, which states
1022        that \n is character 10 (hex 0A), but it also went horribly wrong when
1023        "newline" was defined as CRLF. This has been fixed.
1025     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1026        was being set to -1 for the "end of line" case (supposedly a value that no
1027        character can have). Though this value is never used (the check for end of
1028        line is "zero bytes in current character"), it caused compiler complaints.
1029        I've changed it to 0xffffffff.
1031     8. In pcre_version.c, the version string was being built by a sequence of
1032        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1033        string (as it is for production releases) called a macro with an empty
1034        argument. The C standard says the result of this is undefined. The gcc
1035        compiler treats it as an empty string (which was what was wanted) but it is
1036        reported that Visual C gives an error. The source has been hacked around to
1037        avoid this problem.
1039     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1040        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1041        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1042        of them did).
1044    10. Originally, pcretest opened its input and output without "b"; then I was
1045        told that "b" was needed in some environments, so it was added for release
1046        5.0 to both the input and output. (It makes no difference on Unix-like
1047        systems.) Later I was told that it is wrong for the input on Windows. I've
1048        now abstracted the modes into two macros, to make it easier to fiddle with
1049        them, and removed "b" from the input mode under Windows.
1051    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1053    12. Added -help and --help to pcretest as an official way of being reminded
1054        of the options.
1056    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1057        and pcrecpp.cc because they annoy compilers at high warning levels.
1059    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1061    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1062        scripts are not C programs :-) and which was not noticed because it works
1063        on Linux.
1065    16. pcretest is supposed to handle any length of pattern and data line (as one
1066        line or as a continued sequence of lines) by extending its input buffer if
1067        necessary. This feature was broken for very long pattern lines, leading to
1068        a string of junk being passed to pcre_compile() if the pattern was longer
1069        than about 50K.
1071    17. I have done a major re-factoring of the way pcre_compile() computes the
1072        amount of memory needed for a compiled pattern. Previously, there was code
1073        that made a preliminary scan of the pattern in order to do this. That was
1074        OK when PCRE was new, but as the facilities have expanded, it has become
1075        harder and harder to keep it in step with the real compile phase, and there
1076        have been a number of bugs (see for example, 4 above). I have now found a
1077        cunning way of running the real compile function in a "fake" mode that
1078        enables it to compute how much memory it would need, while actually only
1079        ever using a few hundred bytes of working memory and without too many
1080        tests of the mode. This should make future maintenance and development
1081        easier. A side effect of this work is that the limit of 200 on the nesting
1082        depth of parentheses has been removed (though this was never a serious
1083        limitation, I suspect). However, there is a downside: pcre_compile() now
1084        runs more slowly than before (30% or more, depending on the pattern). I
1085        hope this isn't a big issue. There is no effect on runtime performance.
1087    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1088        newline (only possible for the last line of a file) and it was a
1089        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1091    19. Added additional timing features to pcretest. (1) The -tm option now times
1092        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1093        separate command line item, by a number that specifies the number of
1094        repeats to use when timing. The default is 50000; this gives better
1095        precision, but takes uncomfortably long for very large patterns.
1097    20. Extended pcre_study() to be more clever in cases where a branch of a
1098        subpattern has no definite first character. For example, (a*|b*)[cd] would
1099        previously give no result from pcre_study(). Now it recognizes that the
1100        first character must be a, b, c, or d.
1102    21. There was an incorrect error "recursive call could loop indefinitely" if
1103        a subpattern (or the entire pattern) that was being tested for matching an
1104        empty string contained only one non-empty item after a nested subpattern.
1105        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1106        incorrectly, because the \d was being skipped in the check.
1108    22. The pcretest program now has a new pattern option /B and a command line
1109        option -b, which is equivalent to adding /B to every pattern. This causes
1110        it to show the compiled bytecode, without the additional information that
1111        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1112        is the same as /B/I).
1114    23. A new optimization is now able automatically to treat some sequences such
1115        as a*b as a*+b. More specifically, if something simple (such as a character
1116        or a simple class like \d) has an unlimited quantifier, and is followed by
1117        something that cannot possibly match the quantified thing, the quantifier
1118        is automatically "possessified".
1120    24. A recursive reference to a subpattern whose number was greater than 39
1121        went wrong under certain circumstances in UTF-8 mode. This bug could also
1122        have affected the operation of pcre_study().
1124    25. Realized that a little bit of performance could be had by replacing
1125        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1127    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1129    27. Possessive quantifiers such as a++ were previously implemented by turning
1130        them into atomic groups such as ($>a+). Now they have their own opcodes,
1131        which improves performance. This includes the automatically created ones
1132        from 23 above.
1134    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1135        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1136        the first matched character to be a colon. This applied both to named and
1137        numbered groups.
1139    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1141    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1142        building PCRE on Windows easier, so I have included it in the distribution.
1144    31. There is now a check in pcretest against a ridiculously large number being
1145        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1146        loop, the loop is abandoned.
1148    32. Forward references to subpatterns in conditions such as (?(2)...) where
1149        subpattern 2 is defined later cause pcre_compile() to search forwards in
1150        the pattern for the relevant set of parentheses. This search went wrong
1151        when there were unescaped parentheses in a character class, parentheses
1152        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1154    33. "Subroutine" calls and backreferences were previously restricted to
1155        referencing subpatterns earlier in the regex. This restriction has now
1156        been removed.
1158    34. Added a number of extra features that are going to be in Perl 5.10. On the
1159        whole, these are just syntactic alternatives for features that PCRE had
1160        previously implemented using the Python syntax or my own invention. The
1161        other formats are all retained for compatibility.
1163        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1164            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1165            also .NET compatible.
1167        (b) A recursion or subroutine call to a named group can now be defined as
1168            (?&name) as well as (?P>name).
1170        (c) A backreference to a named group can now be defined as \k<name> or
1171            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1172            5.10, are also .NET compatible.
1174        (d) A conditional reference to a named group can now use the syntax
1175            (?(<name>) or (?('name') as well as (?(name).
1177        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1178            groups (named and numbered) that are never evaluated inline, but can be
1179            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1180            is always false. There may be only one alternative in such a group.
1182        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1183            as the simple (?(R). The condition is true only if the most recent
1184            recursion is that of the given number or name. It does not search out
1185            through the entire recursion stack.
1187        (g) The escape \gN or \g{N} has been added, where N is a positive or
1188            negative number, specifying an absolute or relative reference.
1190    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1191        some "unreachable code" warnings.
1193    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1194        things, this adds five new scripts.
1196    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1197        There were also incompatibilities regarding the handling of \Q..\E inside
1198        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1199        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1201    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1202        matches an empty string, and forcibly breaks the loop. There were bugs in
1203        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1204        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1205        separate and independent bugs (that affected different cases) have been
1206        fixed.
1208    39. Refactored the code to abolish the use of different opcodes for small
1209        capturing bracket numbers. This is a tidy that I avoided doing when I
1210        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1211        The new approach is not only tidier, it makes it possible to reduce the
1212        memory needed to fix the previous bug (38).
1214    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1215        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1216        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1217        mode.
1219    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1220        report.
1222    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1223        copy construction and assignment in the C++ wrapper.
1225    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1226        couple of bugs that could have given wrong results in the "--newline=crlf"
1227        case.
1229    44. Added a number of casts and did some reorganization of signed/unsigned int
1230        variables following suggestions from Dair Grant. Also renamed the variable
1231        "this" as "item" because it is a C++ keyword.
1233    45. Arranged for dftables to add
1235          #include "pcre_internal.h"
1237        to pcre_chartables.c because without it, gcc 4.x may remove the array
1238        definition from the final binary if PCRE is built into a static library and
1239        dead code stripping is activated.
1241    46. For an unanchored pattern, if a match attempt fails at the start of a
1242        newline sequence, and the newline setting is CRLF or ANY, and the next two
1243        characters are CRLF, advance by two characters instead of one.
1246    Version 6.7 04-Jul-06
1247    ---------------------
1249     1. In order to handle tests when input lines are enormously long, pcretest has
1250        been re-factored so that it automatically extends its buffers when
1251        necessary. The code is crude, but this _is_ just a test program. The
1252        default size has been increased from 32K to 50K.
1254     2. The code in pcre_study() was using the value of the re argument before
1255        testing it for NULL. (Of course, in any sensible call of the function, it
1256        won't be NULL.)
1258     3. The memmove() emulation function in pcre_internal.h, which is used on
1259        systems that lack both memmove() and bcopy() - that is, hardly ever -
1260        was missing a "static" storage class specifier.
1262     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1263        containing an extended class (one that cannot be represented by a bitmap
1264        because it contains high-valued characters or Unicode property items, e.g.
1265        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1266        pattern, but PCRE should not loop if you do not (it no longer does).
1267        [Detail: two cases were found: (a) a repeated subpattern containing an
1268        extended class; (b) a recursive reference to a subpattern that followed a
1269        previous extended class. It wasn't skipping over the extended class
1270        correctly when UTF-8 mode was not set.]
1272     5. A negated single-character class was not being recognized as fixed-length
1273        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1274        compile error "lookbehind assertion is not fixed length".
1276     6. The RunPerlTest auxiliary script was showing an unexpected difference
1277        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1278        write a Perl script that can interpret lines of an input file either as
1279        byte characters or as UTF-8, which is what "perltest" was being required to
1280        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1281        can't do is switch easily at run time between having the "use utf8;" pragma
1282        or not. In the end, I fudged it by using the RunPerlTest script to insert
1283        "use utf8;" explicitly for the UTF-8 tests.
1285     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1286        the end of the subject string, contrary to the documentation and to what
1287        Perl does. This was true of both matching functions. Now it matches only at
1288        the start of the subject and immediately after *internal* newlines.
1290     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1291        a pointer to an int instead of a pointer to an unsigned long int. This
1292        caused problems on 64-bit systems.
1294     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1295        instance of the 'standard' template library not being so standard".
1297    10. There was no check on the number of named subpatterns nor the maximum
1298        length of a subpattern name. The product of these values is used to compute
1299        the size of the memory block for a compiled pattern. By supplying a very
1300        long subpattern name and a large number of named subpatterns, the size
1301        computation could be caused to overflow. This is now prevented by limiting
1302        the length of names to 32 characters, and the number of named subpatterns
1303        to 10,000.
1305    11. Subpatterns that are repeated with specific counts have to be replicated in
1306        the compiled pattern. The size of memory for this was computed from the
1307        length of the subpattern and the repeat count. The latter is limited to
1308        65535, but there was no limit on the former, meaning that integer overflow
1309        could in principle occur. The compiled length of a repeated subpattern is
1310        now limited to 30,000 bytes in order to prevent this.
1312    12. Added the optional facility to have named substrings with the same name.
1314    13. Added the ability to use a named substring as a condition, using the
1315        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1316        are numbers (not recommended). Forward references are permitted.
1318    14. Added forward references in named backreferences (if you see what I mean).
1320    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1321        pattern could run off the end of the subject. For example, the pattern
1322        "(?s)(.{1,5})"8 did this with the subject "ab".
1324    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1325        PCRE_CASELESS was set when matching characters that were quantified with ?
1326        or *.
1328    17. A character class other than a single negated character that had a minimum
1329        but no maximum quantifier - for example [ab]{6,} - was not handled
1330        correctly by pce_dfa_exec(). It would match only one character.
1332    18. A valid (though odd) pattern that looked like a POSIX character
1333        class but used an invalid character after [ (for example [[,abc,]]) caused
1334        pcre_compile() to give the error "Failed: internal error: code overflow" or
1335        in some cases to crash with a glibc free() error. This could even happen if
1336        the pattern terminated after [[ but there just happened to be a sequence of
1337        letters, a binary zero, and a closing ] in the memory that followed.
1339    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1340        over the years. Originally (before any Unicode support), just the bottom 8
1341        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1342        output from "man perlunicode" includes this:
1344          The regular expression compiler produces polymorphic opcodes.  That
1345          is, the pattern adapts to the data and automatically switches to
1346          the Unicode character scheme when presented with Unicode data--or
1347          instead uses a traditional byte scheme when presented with byte
1348          data.
1350        Sadly, a wide octal escape does not cause a switch, and in a string with
1351        no other multibyte characters, these octal escapes are treated as before.
1352        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1353        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1354        Unicode string.
1356        I have not perpetrated such confusion in PCRE. Up till now, it took just
1357        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1358        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1359        translate to the appropriate multibyte character.
1361    29. Applied some refactoring to reduce the number of warnings from Microsoft
1362        and Borland compilers. This has included removing the fudge introduced
1363        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1364        a warning about an unused variable.
1366    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1367        characters since release 4.0, because Perl (from release 5.004) does not.
1368        [Or at least, is documented not to: some releases seem to be in conflict
1369        with the documentation.] However, when a pattern was studied with
1370        pcre_study() and all its branches started with \s, PCRE still included VT
1371        as a possible starting character. Of course, this did no harm; it just
1372        caused an unnecessary match attempt.
1374    22. Removed a now-redundant internal flag bit that recorded the fact that case
1375        dependency changed within the pattern. This was once needed for "required
1376        byte" processing, but is no longer used. This recovers a now-scarce options
1377        bit. Also moved the least significant internal flag bit to the most-
1378        significant bit of the word, which was not previously used (hangover from
1379        the days when it was an int rather than a uint) to free up another bit for
1380        the future.
1382    23. Added support for CRLF line endings as well as CR and LF. As well as the
1383        default being selectable at build time, it can now be changed at runtime
1384        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1385        specify that it is scanning data with non-default line endings.
1387    24. Changed the definition of CXXLINK to make it agree with the definition of
1388        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1390    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1391        recursions. This makes a big different to stack usage for some patterns.
1393    26. If a subpattern containing a named recursion or subroutine reference such
1394        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1395        the space required for the compiled pattern went wrong and gave too small a
1396        value. Depending on the environment, this could lead to "Failed: internal
1397        error: code overflow at offset 49" or "glibc detected double free or
1398        corruption" errors.
1400    27. Applied patches from Google (a) to support the new newline modes and (b) to
1401        advance over multibyte UTF-8 characters in GlobalReplace.
1403    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1404        difference for some implementation of PCRE in some Windows version.
1406    29. Added some extra testing facilities to pcretest:
1408        \q<number>   in a data line sets the "match limit" value
1409        \Q<number>   in a data line sets the "match recursion limt" value
1410        -S <number>  sets the stack size, where <number> is in megabytes
1412        The -S option isn't available for Windows.
1415    Version 6.6 06-Feb-06
1416    ---------------------
1418     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1419        in pcreposix.h. I have copied the definition from pcre.h.
1421     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1422        because pcre.h is no longer a built file.
1424     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1425        not normally included in the compiled code.
1428  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
1429  ---------------------  ---------------------

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