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revision 85 by nigel, Sat Feb 24 21:41:13 2007 UTC revision 383 by ph10, Sun Mar 8 15:26:59 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.9 xx-xxx-09
5    ---------------------
7    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
8        (pcretest), all targets were linked against these libraries. This included
9        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
10        libraries. This caused unwanted dependencies to be created. This problem
11        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
12        pcretest is linked with readline.
14    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
15        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
16        moved outside it again, because FALSE and TRUE are already defined in AIX,
17        but BOOL is not.
19    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
20        PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.
22    4.  The pcregrep documentation said spaces were inserted as well as colons (or
23        hyphens) following file names and line numbers when outputting matching
24        lines. This is not true; no spaces are inserted. I have also clarified the
25        wording for the --colour (or --color) option.
27    5.  In pcregrep, when --colour was used with -o, the list of matching strings
28        was not coloured; this is different to GNU grep, so I have changed it to be
29        the same.
31    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
32        each matching line was coloured. Now it goes on to look for further matches
33        of any of the test patterns, which is the same behaviour as GNU grep.
35    7.  A pattern that could match an empty string could cause pcregrep to loop; it
36        doesn't make sense to accept an empty string match in pcregrep, so I have
37        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
38        seems to be how GNU grep behaves.
40    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
41        start or after a newline", because the conditional assertion was not being
42        correctly handled. The rule now is that both the assertion and what follows
43        in the first alternative must satisfy the test.
45    9.  If auto-callout was enabled in a pattern with a conditional group, PCRE
46        could crash during matching.
48    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
49        used for matching.
52    Version 7.8 05-Sep-08
53    ---------------------
55    1.  Replaced UCP searching code with optimized version as implemented for Ad
56        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
57        stage table and inline lookup instead of a function, giving speed ups of 2
58        to 5 times on some simple patterns that I tested. Permission was given to
59        distribute the MultiStage2.py script that generates the tables (it's not in
60        the tarball, but is in the Subversion repository).
62    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
63        scripts.
65    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
66        a group with a zero qualifier. The result of the study could be incorrect,
67        or the function might crash, depending on the pattern.
69    4.  Caseless matching was not working for non-ASCII characters in back
70        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
71        It now works when Unicode Property Support is available.
73    5.  In pcretest, an escape such as \x{de} in the data was always generating
74        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
75        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
76        truncation.
78    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
80    7.  Added two (int) casts to pcregrep when printing the difference of two
81        pointers, in case they are 64-bit values.
83    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
84        test 2 if it fails.
86    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
87        and a #define of that name to empty if it is not externally set. This is to
88        allow users of MSVC to set it if necessary.
90    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
91        the convenience functions in the pcre_get.c source file.
93    11. An option change at the start of a pattern that had top-level alternatives
94        could cause overwriting and/or a crash. This command provoked a crash in
95        some environments:
97          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
99        This potential security problem was recorded as CVE-2008-2371.
101    12. For a pattern where the match had to start at the beginning or immediately
102        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
103        pcre_dfa_exec() could read past the end of the passed subject if there was
104        no match. To help with detecting such bugs (e.g. with valgrind), I modified
105        pcretest so that it places the subject at the end of its malloc-ed buffer.
107    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
108        exec() might read past the end of the data buffer in UTF-8 mode.
110    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
111        the data contained the byte 0x85 as part of a UTF-8 character within its
112        first line. This applied both to normal and DFA matching.
114    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
115        /^[^d]*?$/8 failed to match "abc".
117    16. Added a missing copyright notice to pcrecpp_internal.h.
119    17. Make it more clear in the documentation that values returned from
120        pcre_exec() in ovector are byte offsets, not character counts.
122    18. Tidied a few places to stop certain compilers from issuing warnings.
124    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
125        supplied by Stefan Weber. I made a further small update for 7.8 because
126        there is a change of source arrangements: the pcre_searchfuncs.c module is
127        replaced by pcre_ucd.c.
130    Version 7.7 07-May-08
131    ---------------------
133    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
134        a string to a long long, pretend we don't even have a long long." This is
135        done by checking for the strtoq, strtoll, and _strtoi64 functions.
137    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
138        pre-7.6 versions, which defined a global no_arg variable instead of putting
139        it in the RE class. (See also #8 below.)
141    3.  Remove a line of dead code, identified by coverity and reported by Nuno
142        Lopes.
144    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
146        (1) The include/exclude patterns were being applied to the whole pathnames
147            of files, instead of just to the final components.
149        (2) If there was more than one level of directory, the subdirectories were
150            skipped unless they satisfied the include/exclude conditions. This is
151            inconsistent with GNU grep (and could even be seen as contrary to the
152            pcregrep specification - which I improved to make it absolutely clear).
153            The action now is always to scan all levels of directory, and just
154            apply the include/exclude patterns to regular files.
156    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
157        --exclude_dir in the tests to avoid scanning .svn directories.
159    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
160        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
161        doesn't support NULs in patterns.
163    7.  Added some missing "const"s to declarations of static tables in
164        pcre_compile.c and pcre_dfa_exec.c.
166    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
167        caused by fix #2  above. (Subsequently also a second patch to fix the
168        first patch. And a third patch - this was a messy problem.)
170    9.  Applied Craig's patch to remove the use of push_back().
172    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
173        matching function regexec().
175    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
176        which, however, unlike Perl's \g{...}, are subroutine calls, not back
177        references. PCRE supports relative numbers with this syntax (I don't think
178        Oniguruma does).
180    12. Previously, a group with a zero repeat such as (...){0} was completely
181        omitted from the compiled regex. However, this means that if the group
182        was called as a subroutine from elsewhere in the pattern, things went wrong
183        (an internal error was given). Such groups are now left in the compiled
184        pattern, with a new opcode that causes them to be skipped at execution
185        time.
187    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
188        to the way PCRE behaves:
190        (a) A lone ] character is dis-allowed (Perl treats it as data).
192        (b) A back reference to an unmatched subpattern matches an empty string
193            (Perl fails the current match path).
195        (c) A data ] in a character class must be notated as \] because if the
196            first data character in a class is ], it defines an empty class. (In
197            Perl it is not possible to have an empty class.) The empty class []
198            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
199            The negative empty class [^] matches any one character, independently
200            of the DOTALL setting.
202    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
203        non-existent subpattern following a character class starting with ']' and
204        containing () gave an internal compiling error instead of "reference to
205        non-existent subpattern". Fortunately, when the pattern did exist, the
206        compiled code was correct. (When scanning forwards to check for the
207        existencd of the subpattern, it was treating the data ']' as terminating
208        the class, so got the count wrong. When actually compiling, the reference
209        was subsequently set up correctly.)
211    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
212        it was being rejected as not supported by pcre_dfa_exec(), even though
213        other assertions are supported. I have made pcre_dfa_exec() support
214        (*FAIL).
216    16. The implementation of 13c above involved the invention of a new opcode,
217        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
218        cannot be changed at match time, I realized I could make a small
219        improvement to matching performance by compiling OP_ALLANY instead of
220        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
221        on the OP_ANY path.
223    17. Compiling pcretest on Windows with readline support failed without the
224        following two fixes: (1) Make the unistd.h include conditional on
225        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
227    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
228        ncurses library to be included for pcretest when ReadLine support is
229        requested, but also to allow for it to be overridden. This patch came from
230        Daniel Bergström.
232    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
233        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
234        any errors with the current Unicode tables. Thanks to Peter Kankowski for
235        spotting this.
238    Version 7.6 28-Jan-08
239    ---------------------
241    1.  A character class containing a very large number of characters with
242        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
243        overflow.
245    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
246        HAVE_LONG_LONG is not defined.
248    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
249        bring them up to date and include new features. This patch includes:
251        - Fixed PH's badly added libz and libbz2 support.
252        - Fixed a problem with static linking.
253        - Added pcredemo. [But later removed - see 7 below.]
254        - Fixed dftables problem and added an option.
255        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
256            HAVE_LONG_LONG.
257        - Added readline support for pcretest.
258        - Added an listing of the option settings after cmake has run.
260    4.  A user submitted a patch to Makefile that makes it easy to create
261        "pcre.dll" under mingw when using Configure/Make. I added stuff to
262        Makefile.am that cause it to include this special target, without
263        affecting anything else. Note that the same mingw target plus all
264        the other distribution libraries and programs are now supported
265        when configuring with CMake (see 6 below) instead of with
266        Configure/Make.
268    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
269        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
270        exported in the Windows port". It has not yet been confirmed that the patch
271        solves the problem, but it does no harm.
273    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
274        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
275        with CMake, and also correct the comment about stack recursion.
277    7.  Remove the automatic building of pcredemo from the ./configure system and
278        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
279        of a program that users should build themselves after PCRE is installed, so
280        building it automatically is not really right. What is more, it gave
281        trouble in some build environments.
283    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
286    Version 7.5 10-Jan-08
287    ---------------------
289    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
290        values in parens when parsing an RE using the C++ wrapper."
292    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
293        Characters greater than 255 were excluded from the class instead of being
294        included.
296    3.  The same bug as (2) above applied to negated POSIX classes such as
297        [:^space:].
299    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
300        defined or documented. It seems to have been a typo for PCRE_STATIC, so
301        I have changed it.
303    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
304        first named subpattern) and a construct such as (?&a) would reference the
305        first named subpattern whose name started with "a" (in other words, the
306        length check was missing). Both these problems are fixed. "Subpattern name
307        expected" is now given for (?&) (a zero-length name), and this patch also
308        makes it give the same error for \k'' (previously it complained that that
309        was a reference to a non-existent subpattern).
311    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
312        this is right because (?- can be followed by option settings as well as by
313        digits. I have, however, made the messages clearer.
315    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
316        than the number used in the conditional) now cause a compile-time error.
317        This is actually not compatible with Perl, which accepts such patterns, but
318        treats the conditional as always being FALSE (as PCRE used to), but it
319        seems to me that giving a diagnostic is better.
321    8.  Change "alphameric" to the more common word "alphanumeric" in comments
322        and messages.
324    9.  Fix two occurrences of "backslash" in comments that should have been
325        "backspace".
327    10. Remove two redundant lines of code that can never be obeyed (their function
328        was moved elsewhere).
330    11. The program that makes PCRE's Unicode character property table had a bug
331        which caused it to generate incorrect table entries for sequences of
332        characters that have the same character type, but are in different scripts.
333        It amalgamated them into a single range, with the script of the first of
334        them. In other words, some characters were in the wrong script. There were
335        thirteen such cases, affecting characters in the following ranges:
337          U+002b0 - U+002c1
338          U+0060c - U+0060d
339          U+0061e - U+00612
340          U+0064b - U+0065e
341          U+0074d - U+0076d
342          U+01800 - U+01805
343          U+01d00 - U+01d77
344          U+01d9b - U+01dbf
345          U+0200b - U+0200f
346          U+030fc - U+030fe
347          U+03260 - U+0327f
348          U+0fb46 - U+0fbb1
349          U+10450 - U+1049d
351    12. The -o option (show only the matching part of a line) for pcregrep was not
352        compatible with GNU grep in that, if there was more than one match in a
353        line, it showed only the first of them. It now behaves in the same way as
354        GNU grep.
356    13. If the -o and -v options were combined for pcregrep, it printed a blank
357        line for every non-matching line. GNU grep prints nothing, and pcregrep now
358        does the same. The return code can be used to tell if there were any
359        non-matching lines.
361    14. Added --file-offsets and --line-offsets to pcregrep.
363    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
364        infinitely looping recursion. The bug was that positive lookaheads were not
365        being skipped when checking for a possible empty match (negative lookaheads
366        and both kinds of lookbehind were skipped).
368    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
369        inclusion of <windows.h> to before rather than after the definition of
370        INVALID_FILE_ATTRIBUTES (patch from David Byron).
372    17. Specifying a possessive quantifier with a specific limit for a Unicode
373        character property caused pcre_compile() to compile bad code, which led at
374        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
375        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
376        caused the error; without that there was no problem.
378    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
380    19. Added --enable-pcretest-libreadline.
382    20. In pcrecpp.cc, the variable 'count' was incremented twice in
383        RE::GlobalReplace(). As a result, the number of replacements returned was
384        double what it should be. I removed one of the increments, but Craig sent a
385        later patch that removed the other one (the right fix) and added unit tests
386        that check the return values (which was not done before).
388    21. Several CMake things:
390        (1) Arranged that, when cmake is used on Unix, the libraries end up with
391            the names libpcre and libpcreposix, not just pcre and pcreposix.
393        (2) The above change means that pcretest and pcregrep are now correctly
394            linked with the newly-built libraries, not previously installed ones.
398    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
399        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
400        UTF-8 newline character). The key issue is that the pattern starts .*;
401        this means that the match must be either at the beginning, or after a
402        newline. The bug was in the code for advancing after a failed match and
403        checking that the new position followed a newline. It was not taking
404        account of UTF-8 characters correctly.
406    23. PCRE was behaving differently from Perl in the way it recognized POSIX
407        character classes. PCRE was not treating the sequence [:...:] as a
408        character class unless the ... were all letters. Perl, however, seems to
409        allow any characters between [: and :], though of course it rejects as
410        unknown any "names" that contain non-letters, because all the known class
411        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
412        for example, whereas PCRE did not - it did not recognize a POSIX character
413        class. This seemed a bit dangerous, so the code has been changed to be
414        closer to Perl. The behaviour is not identical to Perl, because PCRE will
415        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
416        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
417        Perl does, and where it didn't before.
419    24. Rewrite so as to remove the single use of %n from pcregrep because in some
420        Windows environments %n is disabled by default.
423    Version 7.4 21-Sep-07
424    ---------------------
426    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
427        means that a class such as [\s] counted as "explicit reference to CR or
428        LF". That isn't really right - the whole point of the change was to try to
429        help when there was an actual mention of one of the two characters. So now
430        the change happens only if \r or \n (or a literal CR or LF) character is
431        encountered.
433    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
434        of both had grown to the point where there were only 3 bits left.
435        Fortunately, there was spare space in the data structure, and so I have
436        moved the internal flags into a new 16-bit field to free up more option
437        bits.
439    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
440        but did not set the internal JCHANGED flag - either of these is enough to
441        control the way the "get" function works - but the PCRE_INFO_JCHANGED
442        facility is supposed to tell if (?J) was ever used, so now (?J) at the
443        start sets both bits.
445    4.  Added options (at build time, compile time, exec time) to change \R from
446        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
448    5.  doc/pcresyntax.html was missing from the distribution.
450    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
451        compatibility, even though it is no longer used.
453    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
454        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
455        windows.h file is present (where different names are used). [This was
456        reversed later after testing - see 16 below.]
458    8.  Changed all #include <config.h> to #include "config.h". There were also
459        some further <pcre.h> cases that I changed to "pcre.h".
461    9.  When pcregrep was used with the --colour option, it missed the line ending
462        sequence off the lines that it output.
464    10. It was pointed out to me that arrays of string pointers cause lots of
465        relocations when a shared library is dynamically loaded. A technique of
466        using a single long string with a table of offsets can drastically reduce
467        these. I have refactored PCRE in four places to do this. The result is
468        dramatic:
470          Originally:                          290
471          After changing UCP table:            187
472          After changing error message table:   43
473          After changing table of "verbs"       36
474          After changing table of Posix names   22
476        Thanks to the folks working on Gregex for glib for this insight.
478    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
479        unicode-properties was also set.
481    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
483    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
484        checked only for CRLF.
486    14. Added casts to pcretest.c to avoid compiler warnings.
488    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
490    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
491        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
492        entirely. This removes changes made in 7 above.
494    17. The CMake files have been updated, and there is now more information about
495        building with CMake in the NON-UNIX-USE document.
498    Version 7.3 28-Aug-07
499    ---------------------
501     1. In the rejigging of the build system that eventually resulted in 7.1, the
502        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
503        brackets there is not right, since it causes compilers to look for an
504        installed pcre.h, not the version that is in the source that is being
505        compiled (which of course may be different). I have changed it back to:
507          #include "pcre.h"
509        I have a vague recollection that the change was concerned with compiling in
510        different directories, but in the new build system, that is taken care of
511        by the VPATH setting the Makefile.
513     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
514        when the subject happened to end in the byte 0x85 (e.g. if the last
515        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
516        characters but of course it shouldn't be taken as a newline when it is part
517        of another character. The bug was that, for an unlimited repeat of . in
518        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
519        characters when looking for a newline.
521     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
523     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
524        in debug output.
526     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
527        long printing in the pcrecpp unittest when running under MinGW.
529     6. ESC_K was left out of the EBCDIC table.
531     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
532        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
533        limit also applies to "virtual nesting" when a pattern is recursive, and in
534        this case 1000 isn't so big. I have been able to remove this limit at the
535        expense of backing off one optimization in certain circumstances. Normally,
536        when pcre_exec() would call its internal match() function recursively and
537        immediately return the result unconditionally, it uses a "tail recursion"
538        feature to save stack. However, when a subpattern that can match an empty
539        string has an unlimited repetition quantifier, it no longer makes this
540        optimization. That gives it a stack frame in which to save the data for
541        checking that an empty string has been matched. Previously this was taken
542        from the 1000-entry workspace that had been reserved. So now there is no
543        explicit limit, but more stack is used.
545     8. Applied Daniel's patches to solve problems with the import/export magic
546        syntax that is required for Windows, and which was going wrong for the
547        pcreposix and pcrecpp parts of the library. These were overlooked when this
548        problem was solved for the main library.
550     9. There were some crude static tests to avoid integer overflow when computing
551        the size of patterns that contain repeated groups with explicit upper
552        limits. As the maximum quantifier is 65535, the maximum group length was
553        set at 30,000 so that the product of these two numbers did not overflow a
554        32-bit integer. However, it turns out that people want to use groups that
555        are longer than 30,000 bytes (though not repeat them that many times).
556        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
557        made it possible to implement the integer overflow checks in a much more
558        dynamic way, which I have now done. The artificial limitation on group
559        length has been removed - we now have only the limit on the total length of
560        the compiled pattern, which depends on the LINK_SIZE setting.
562    10. Fixed a bug in the documentation for get/copy named substring when
563        duplicate names are permitted. If none of the named substrings are set, the
564        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
565        empty string.
567    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
568        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
569        because the ] is interpreted as the first data character and the
570        terminating ] is not found. PCRE has been made compatible with Perl in this
571        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
572        cause memory overwriting.
574    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
575        string has been matched (to stop an infinite loop). It was not recognizing
576        a conditional subpattern that could match an empty string if that
577        subpattern was within another subpattern. For example, it looped when
578        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
579        condition was not nested. This bug has been fixed.
581    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
582        past the start of the subject in the presence of bytes with the top bit
583        set, for example "\x8aBCD".
585    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
586        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
588    14. Optimized (?!) to (*FAIL).
590    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
591        This restricts code points to be within the range 0 to 0x10FFFF, excluding
592        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
593        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
594        does: it's just the validity check that is more restrictive.
596    16. Inserted checks for integer overflows during escape sequence (backslash)
597        processing, and also fixed erroneous offset values for syntax errors during
598        backslash processing.
600    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
601        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
603    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
604        caused an overrun.
606    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
607        something other than just ASCII characters) inside a group that had an
608        unlimited repeat caused a loop at compile time (while checking to see
609        whether the group could match an empty string).
611    20. Debugging a pattern containing \p or \P could cause a crash. For example,
612        [\P{Any}] did so. (Error in the code for printing property names.)
614    21. An orphan \E inside a character class could cause a crash.
616    22. A repeated capturing bracket such as (A)? could cause a wild memory
617        reference during compilation.
619    23. There are several functions in pcre_compile() that scan along a compiled
620        expression for various reasons (e.g. to see if it's fixed length for look
621        behind). There were bugs in these functions when a repeated \p or \P was
622        present in the pattern. These operators have additional parameters compared
623        with \d, etc, and these were not being taken into account when moving along
624        the compiled data. Specifically:
626        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
627            length.
629        (b) An item such as \pL+ within a repeated group could cause crashes or
630            loops.
632        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
633            "reference to non-existent subpattern" error.
635        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
637    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
638        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
640    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
642    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
643        character were causing crashes (broken optimization).
645    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
646        \p or \P) caused a compile-time loop.
648    28. More problems have arisen in unanchored patterns when CRLF is a valid line
649        break. For example, the unstudied pattern [\r\n]A does not match the string
650        "\r\nA" because change 7.0/46 below moves the current point on by two
651        characters after failing to match at the start. However, the pattern \nA
652        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
653        the same is true. There doesn't seem any very clean way out of this, but
654        what I have chosen to do makes the common cases work: PCRE now takes note
655        of whether there can be an explicit match for \r or \n anywhere in the
656        pattern, and if so, 7.0/46 no longer applies. As part of this change,
657        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
658        pattern has explicit CR or LF references.
660    29. Added (*CR) etc for changing newline setting at start of pattern.
663    Version 7.2 19-Jun-07
664    ---------------------
666     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
667        which is apparently normally available under Windows.
669     2. Re-jig the pcregrep tests with different newline settings in an attempt
670        to make them independent of the local environment's newline setting.
672     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
674     4. Some of the "internals" tests were previously cut out when the link size
675        was not 2, because the output contained actual offsets. The recent new
676        "Z" feature of pcretest means that these can be cut out, making the tests
677        usable with all link sizes.
679     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
680        stack recursion. This gives a massive performance boost under BSD, but just
681        a small improvement under Linux. However, it saves one field in the frame
682        in all cases.
684     6. Added more features from the forthcoming Perl 5.10:
686        (a) (?-n) (where n is a string of digits) is a relative subroutine or
687            recursion call. It refers to the nth most recently opened parentheses.
689        (b) (?+n) is also a relative subroutine call; it refers to the nth next
690            to be opened parentheses.
692        (c) Conditions that refer to capturing parentheses can be specified
693            relatively, for example, (?(-2)... or (?(+3)...
695        (d) \K resets the start of the current match so that everything before
696            is not part of it.
698        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
700        (f) \g{name} is another synonym - part of Perl 5.10's unification of
701            reference syntax.
703        (g) (?| introduces a group in which the numbering of parentheses in each
704            alternative starts with the same number.
706        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
708     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
711     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
712        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
713        for detecting groups that can match an empty string.
715     9. A pattern with a very large number of alternatives (more than several
716        hundred) was running out of internal workspace during the pre-compile
717        phase, where pcre_compile() figures out how much memory will be needed. A
718        bit of new cunning has reduced the workspace needed for groups with
719        alternatives. The 1000-alternative test pattern now uses 12 bytes of
720        workspace instead of running out of the 4096 that are available.
722    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
724    11. Applied patch from Google to remove an optimization that didn't quite work.
725        The report of the bug said:
727          pcrecpp::RE("a*").FullMatch("aaa") matches, while
728          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
729          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
731    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
732        it matched the wrong number of bytes.
735    Version 7.1 24-Apr-07
736    ---------------------
738     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
739        that is more "standard", making use of automake and other Autotools. There
740        is some re-arrangement of the files and adjustment of comments consequent
741        on this.
743     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
744        for recursive directory scanning broke on some systems because the files
745        are not scanned in any specific order and on different systems the order
746        was different. A call to "sort" has been inserted into RunGrepTest for the
747        approprate test as a short-term fix. In the longer term there may be an
748        alternative.
750     3. I had an email from Eric Raymond about problems translating some of PCRE's
751        man pages to HTML (despite the fact that I distribute HTML pages, some
752        people do their own conversions for various reasons). The problems
753        concerned the use of low-level troff macros .br and .in. I have therefore
754        removed all such uses from the man pages (some were redundant, some could
755        be replaced by .nf/.fi pairs). The 132html script that I use to generate
756        HTML has been updated to handle .nf/.fi and to complain if it encounters
757        .br or .in.
759     4. Updated comments in configure.ac that get placed in config.h.in and also
760        arranged for config.h to be included in the distribution, with the name
761        config.h.generic, for the benefit of those who have to compile without
762        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
764     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
765        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
766        makevp.bat for the current PCRE, using the additional files
767        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
769     6. A Windows user reported a minor discrepancy with test 2, which turned out
770        to be caused by a trailing space on an input line that had got lost in his
771        copy. The trailing space was an accident, so I've just removed it.
773     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
774        that is needed.
776     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
777        as "const" (a) because they are and (b) because it helps the PHP
778        maintainers who have recently made a script to detect big data structures
779        in the php code that should be moved to the .rodata section. I remembered
780        to update Builducptable as well, so it won't revert if ucptable.h is ever
781        re-created.
783     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
784        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
785        order to be able to cut out the UTF-8 tables in the latter when UTF-8
786        support is not required. This saves 1.5-2K of code, which is important in
787        some applications.
789        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
790        so as not to refer to the tables, even though these functions will never be
791        called when UTF-8 support is disabled. Otherwise there are problems with a
792        shared library.
794    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
796        (a) It was defining its arguments as char * instead of void *.
798        (b) It was assuming that all moves were upwards in memory; this was true
799            a long time ago when I wrote it, but is no longer the case.
801        The emulated memove() is provided for those environments that have neither
802        memmove() nor bcopy(). I didn't think anyone used it these days, but that
803        is clearly not the case, as these two bugs were recently reported.
805    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
806        and Detrail to create the HTML documentation, the .txt form of the man
807        pages, and it removes trailing spaces from listed files. It also creates
808        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
809        case, it wraps all the #defines with #ifndefs. This script should be run
810        before "make dist".
812    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
813        with Unicode property support.
815        (a) For a maximizing quantifier, if the two different cases of the
816            character were of different lengths in their UTF-8 codings (there are
817            some cases like this - I found 11), and the matching function had to
818            back up over a mixture of the two cases, it incorrectly assumed they
819            were both the same length.
821        (b) When PCRE was configured to use the heap rather than the stack for
822            recursion during matching, it was not correctly preserving the data for
823            the other case of a UTF-8 character when checking ahead for a match
824            while processing a minimizing repeat. If the check also involved
825            matching a wide character, but failed, corruption could cause an
826            erroneous result when trying to check for a repeat of the original
827            character.
829    13. Some tidying changes to the testing mechanism:
831        (a) The RunTest script now detects the internal link size and whether there
832            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
833            values substituted by "configure". (The RunGrepTest script already did
834            this for UTF-8.) The configure.ac script no longer substitutes the
835            relevant variables.
837        (b) The debugging options /B and /D in pcretest show the compiled bytecode
838            with length and offset values. This means that the output is different
839            for different internal link sizes. Test 2 is skipped for link sizes
840            other than 2 because of this, bypassing the problem. Unfortunately,
841            there was also a test in test 3 (the locale tests) that used /B and
842            failed for link sizes other than 2. Rather than cut the whole test out,
843            I have added a new /Z option to pcretest that replaces the length and
844            offset values with spaces. This is now used to make test 3 independent
845            of link size. (Test 2 will be tidied up later.)
847    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
848        segmentation fault instead of returning the appropriate error message.
850    15. In multiline mode when the newline sequence was set to "any", the pattern
851        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
852        This doesn't seem right; it now treats the CRLF combination as the line
853        ending, and so does not match in that case. It's only a pattern such as ^$
854        that would hit this one: something like ^ABC$ would have failed after \r
855        and then tried again after \r\n.
857    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
858        in an attempt to make files that differ only in their line terminators
859        compare equal. This works on Linux.
861    17. Under certain error circumstances pcregrep might try to free random memory
862        as it exited. This is now fixed, thanks to valgrind.
864    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
865        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
866        was because its rules for how to advance for /g after matching an empty
867        string at the end of a line did not allow for this case. They now check for
868        it specially.
870    20. pcretest is supposed to handle patterns and data of any length, by
871        extending its buffers when necessary. It was getting this wrong when the
872        buffer for a data line had to be extended.
874    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
875        CRLF as a newline sequence.
877    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
878        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
879        I have nevertheless tidied it up.
881    23. Added some casts to kill warnings from HP-UX ia64 compiler.
883    24. Added a man page for pcre-config.
886    Version 7.0 19-Dec-06
887    ---------------------
889     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
890        moving to gcc 4.1.1.
892     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
893        sys/time.h, which is documented as needed for this function. It doesn't
894        seem to matter on Linux, but it showed up on some releases of OS X.
896     3. It seems that there are systems where bytes whose values are greater than
897        127 match isprint() in the "C" locale. The "C" locale should be the
898        default when a C program starts up. In most systems, only ASCII printing
899        characters match isprint(). This difference caused the output from pcretest
900        to vary, making some of the tests fail. I have changed pcretest so that:
902        (a) When it is outputting text in the compiled version of a pattern, bytes
903            other than 32-126 are always shown as hex escapes.
905        (b) When it is outputting text that is a matched part of a subject string,
906            it does the same, unless a different locale has been set for the match
907            (using the /L modifier). In this case, it uses isprint() to decide.
909     4. Fixed a major bug that caused incorrect computation of the amount of memory
910        required for a compiled pattern when options that changed within the
911        pattern affected the logic of the preliminary scan that determines the
912        length. The relevant options are -x, and -i in UTF-8 mode. The result was
913        that the computed length was too small. The symptoms of this bug were
914        either the PCRE error "internal error: code overflow" from pcre_compile(),
915        or a glibc crash with a message such as "pcretest: free(): invalid next
916        size (fast)". Examples of patterns that provoked this bug (shown in
917        pcretest format) are:
919          /(?-x: )/x
920          /(?x)(?-x: \s*#\s*)/
921          /((?i)[\x{c0}])/8
922          /(?i:[\x{c0}])/8
924        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
925        is now done differently.
927     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
928        wrapper classes; (b) implement a new function in the C++ scanner that is
929        more efficient than the old way of doing things because it avoids levels of
930        recursion in the regex matching; (c) add a paragraph to the documentation
931        for the FullMatch() function.
933     6. The escape sequence \n was being treated as whatever was defined as
934        "newline". Not only was this contrary to the documentation, which states
935        that \n is character 10 (hex 0A), but it also went horribly wrong when
936        "newline" was defined as CRLF. This has been fixed.
938     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
939        was being set to -1 for the "end of line" case (supposedly a value that no
940        character can have). Though this value is never used (the check for end of
941        line is "zero bytes in current character"), it caused compiler complaints.
942        I've changed it to 0xffffffff.
944     8. In pcre_version.c, the version string was being built by a sequence of
945        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
946        string (as it is for production releases) called a macro with an empty
947        argument. The C standard says the result of this is undefined. The gcc
948        compiler treats it as an empty string (which was what was wanted) but it is
949        reported that Visual C gives an error. The source has been hacked around to
950        avoid this problem.
952     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
953        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
954        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
955        of them did).
957    10. Originally, pcretest opened its input and output without "b"; then I was
958        told that "b" was needed in some environments, so it was added for release
959        5.0 to both the input and output. (It makes no difference on Unix-like
960        systems.) Later I was told that it is wrong for the input on Windows. I've
961        now abstracted the modes into two macros, to make it easier to fiddle with
962        them, and removed "b" from the input mode under Windows.
964    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
966    12. Added -help and --help to pcretest as an official way of being reminded
967        of the options.
969    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
970        and pcrecpp.cc because they annoy compilers at high warning levels.
972    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
974    15. Fixed an occurrence of == in configure.ac that should have been = (shell
975        scripts are not C programs :-) and which was not noticed because it works
976        on Linux.
978    16. pcretest is supposed to handle any length of pattern and data line (as one
979        line or as a continued sequence of lines) by extending its input buffer if
980        necessary. This feature was broken for very long pattern lines, leading to
981        a string of junk being passed to pcre_compile() if the pattern was longer
982        than about 50K.
984    17. I have done a major re-factoring of the way pcre_compile() computes the
985        amount of memory needed for a compiled pattern. Previously, there was code
986        that made a preliminary scan of the pattern in order to do this. That was
987        OK when PCRE was new, but as the facilities have expanded, it has become
988        harder and harder to keep it in step with the real compile phase, and there
989        have been a number of bugs (see for example, 4 above). I have now found a
990        cunning way of running the real compile function in a "fake" mode that
991        enables it to compute how much memory it would need, while actually only
992        ever using a few hundred bytes of working memory and without too many
993        tests of the mode. This should make future maintenance and development
994        easier. A side effect of this work is that the limit of 200 on the nesting
995        depth of parentheses has been removed (though this was never a serious
996        limitation, I suspect). However, there is a downside: pcre_compile() now
997        runs more slowly than before (30% or more, depending on the pattern). I
998        hope this isn't a big issue. There is no effect on runtime performance.
1000    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1001        newline (only possible for the last line of a file) and it was a
1002        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1004    19. Added additional timing features to pcretest. (1) The -tm option now times
1005        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1006        separate command line item, by a number that specifies the number of
1007        repeats to use when timing. The default is 50000; this gives better
1008        precision, but takes uncomfortably long for very large patterns.
1010    20. Extended pcre_study() to be more clever in cases where a branch of a
1011        subpattern has no definite first character. For example, (a*|b*)[cd] would
1012        previously give no result from pcre_study(). Now it recognizes that the
1013        first character must be a, b, c, or d.
1015    21. There was an incorrect error "recursive call could loop indefinitely" if
1016        a subpattern (or the entire pattern) that was being tested for matching an
1017        empty string contained only one non-empty item after a nested subpattern.
1018        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1019        incorrectly, because the \d was being skipped in the check.
1021    22. The pcretest program now has a new pattern option /B and a command line
1022        option -b, which is equivalent to adding /B to every pattern. This causes
1023        it to show the compiled bytecode, without the additional information that
1024        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1025        is the same as /B/I).
1027    23. A new optimization is now able automatically to treat some sequences such
1028        as a*b as a*+b. More specifically, if something simple (such as a character
1029        or a simple class like \d) has an unlimited quantifier, and is followed by
1030        something that cannot possibly match the quantified thing, the quantifier
1031        is automatically "possessified".
1033    24. A recursive reference to a subpattern whose number was greater than 39
1034        went wrong under certain circumstances in UTF-8 mode. This bug could also
1035        have affected the operation of pcre_study().
1037    25. Realized that a little bit of performance could be had by replacing
1038        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1040    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1042    27. Possessive quantifiers such as a++ were previously implemented by turning
1043        them into atomic groups such as ($>a+). Now they have their own opcodes,
1044        which improves performance. This includes the automatically created ones
1045        from 23 above.
1047    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1048        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1049        the first matched character to be a colon. This applied both to named and
1050        numbered groups.
1052    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1054    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1055        building PCRE on Windows easier, so I have included it in the distribution.
1057    31. There is now a check in pcretest against a ridiculously large number being
1058        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1059        loop, the loop is abandoned.
1061    32. Forward references to subpatterns in conditions such as (?(2)...) where
1062        subpattern 2 is defined later cause pcre_compile() to search forwards in
1063        the pattern for the relevant set of parentheses. This search went wrong
1064        when there were unescaped parentheses in a character class, parentheses
1065        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1067    33. "Subroutine" calls and backreferences were previously restricted to
1068        referencing subpatterns earlier in the regex. This restriction has now
1069        been removed.
1071    34. Added a number of extra features that are going to be in Perl 5.10. On the
1072        whole, these are just syntactic alternatives for features that PCRE had
1073        previously implemented using the Python syntax or my own invention. The
1074        other formats are all retained for compatibility.
1076        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1077            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1078            also .NET compatible.
1080        (b) A recursion or subroutine call to a named group can now be defined as
1081            (?&name) as well as (?P>name).
1083        (c) A backreference to a named group can now be defined as \k<name> or
1084            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1085            5.10, are also .NET compatible.
1087        (d) A conditional reference to a named group can now use the syntax
1088            (?(<name>) or (?('name') as well as (?(name).
1090        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1091            groups (named and numbered) that are never evaluated inline, but can be
1092            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1093            is always false. There may be only one alternative in such a group.
1095        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1096            as the simple (?(R). The condition is true only if the most recent
1097            recursion is that of the given number or name. It does not search out
1098            through the entire recursion stack.
1100        (g) The escape \gN or \g{N} has been added, where N is a positive or
1101            negative number, specifying an absolute or relative reference.
1103    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1104        some "unreachable code" warnings.
1106    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1107        things, this adds five new scripts.
1109    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1110        There were also incompatibilities regarding the handling of \Q..\E inside
1111        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1112        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1114    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1115        matches an empty string, and forcibly breaks the loop. There were bugs in
1116        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1117        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1118        separate and independent bugs (that affected different cases) have been
1119        fixed.
1121    39. Refactored the code to abolish the use of different opcodes for small
1122        capturing bracket numbers. This is a tidy that I avoided doing when I
1123        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1124        The new approach is not only tidier, it makes it possible to reduce the
1125        memory needed to fix the previous bug (38).
1127    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1128        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1129        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1130        mode.
1132    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1133        report.
1135    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1136        copy construction and assignment in the C++ wrapper.
1138    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1139        couple of bugs that could have given wrong results in the "--newline=crlf"
1140        case.
1142    44. Added a number of casts and did some reorganization of signed/unsigned int
1143        variables following suggestions from Dair Grant. Also renamed the variable
1144        "this" as "item" because it is a C++ keyword.
1146    45. Arranged for dftables to add
1148          #include "pcre_internal.h"
1150        to pcre_chartables.c because without it, gcc 4.x may remove the array
1151        definition from the final binary if PCRE is built into a static library and
1152        dead code stripping is activated.
1154    46. For an unanchored pattern, if a match attempt fails at the start of a
1155        newline sequence, and the newline setting is CRLF or ANY, and the next two
1156        characters are CRLF, advance by two characters instead of one.
1159    Version 6.7 04-Jul-06
1160    ---------------------
1162     1. In order to handle tests when input lines are enormously long, pcretest has
1163        been re-factored so that it automatically extends its buffers when
1164        necessary. The code is crude, but this _is_ just a test program. The
1165        default size has been increased from 32K to 50K.
1167     2. The code in pcre_study() was using the value of the re argument before
1168        testing it for NULL. (Of course, in any sensible call of the function, it
1169        won't be NULL.)
1171     3. The memmove() emulation function in pcre_internal.h, which is used on
1172        systems that lack both memmove() and bcopy() - that is, hardly ever -
1173        was missing a "static" storage class specifier.
1175     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1176        containing an extended class (one that cannot be represented by a bitmap
1177        because it contains high-valued characters or Unicode property items, e.g.
1178        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1179        pattern, but PCRE should not loop if you do not (it no longer does).
1180        [Detail: two cases were found: (a) a repeated subpattern containing an
1181        extended class; (b) a recursive reference to a subpattern that followed a
1182        previous extended class. It wasn't skipping over the extended class
1183        correctly when UTF-8 mode was not set.]
1185     5. A negated single-character class was not being recognized as fixed-length
1186        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1187        compile error "lookbehind assertion is not fixed length".
1189     6. The RunPerlTest auxiliary script was showing an unexpected difference
1190        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1191        write a Perl script that can interpret lines of an input file either as
1192        byte characters or as UTF-8, which is what "perltest" was being required to
1193        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1194        can't do is switch easily at run time between having the "use utf8;" pragma
1195        or not. In the end, I fudged it by using the RunPerlTest script to insert
1196        "use utf8;" explicitly for the UTF-8 tests.
1198     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1199        the end of the subject string, contrary to the documentation and to what
1200        Perl does. This was true of both matching functions. Now it matches only at
1201        the start of the subject and immediately after *internal* newlines.
1203     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1204        a pointer to an int instead of a pointer to an unsigned long int. This
1205        caused problems on 64-bit systems.
1207     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1208        instance of the 'standard' template library not being so standard".
1210    10. There was no check on the number of named subpatterns nor the maximum
1211        length of a subpattern name. The product of these values is used to compute
1212        the size of the memory block for a compiled pattern. By supplying a very
1213        long subpattern name and a large number of named subpatterns, the size
1214        computation could be caused to overflow. This is now prevented by limiting
1215        the length of names to 32 characters, and the number of named subpatterns
1216        to 10,000.
1218    11. Subpatterns that are repeated with specific counts have to be replicated in
1219        the compiled pattern. The size of memory for this was computed from the
1220        length of the subpattern and the repeat count. The latter is limited to
1221        65535, but there was no limit on the former, meaning that integer overflow
1222        could in principle occur. The compiled length of a repeated subpattern is
1223        now limited to 30,000 bytes in order to prevent this.
1225    12. Added the optional facility to have named substrings with the same name.
1227    13. Added the ability to use a named substring as a condition, using the
1228        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1229        are numbers (not recommended). Forward references are permitted.
1231    14. Added forward references in named backreferences (if you see what I mean).
1233    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1234        pattern could run off the end of the subject. For example, the pattern
1235        "(?s)(.{1,5})"8 did this with the subject "ab".
1237    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1238        PCRE_CASELESS was set when matching characters that were quantified with ?
1239        or *.
1241    17. A character class other than a single negated character that had a minimum
1242        but no maximum quantifier - for example [ab]{6,} - was not handled
1243        correctly by pce_dfa_exec(). It would match only one character.
1245    18. A valid (though odd) pattern that looked like a POSIX character
1246        class but used an invalid character after [ (for example [[,abc,]]) caused
1247        pcre_compile() to give the error "Failed: internal error: code overflow" or
1248        in some cases to crash with a glibc free() error. This could even happen if
1249        the pattern terminated after [[ but there just happened to be a sequence of
1250        letters, a binary zero, and a closing ] in the memory that followed.
1252    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1253        over the years. Originally (before any Unicode support), just the bottom 8
1254        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1255        output from "man perlunicode" includes this:
1257          The regular expression compiler produces polymorphic opcodes.  That
1258          is, the pattern adapts to the data and automatically switches to
1259          the Unicode character scheme when presented with Unicode data--or
1260          instead uses a traditional byte scheme when presented with byte
1261          data.
1263        Sadly, a wide octal escape does not cause a switch, and in a string with
1264        no other multibyte characters, these octal escapes are treated as before.
1265        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1266        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1267        Unicode string.
1269        I have not perpetrated such confusion in PCRE. Up till now, it took just
1270        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1271        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1272        translate to the appropriate multibyte character.
1274    29. Applied some refactoring to reduce the number of warnings from Microsoft
1275        and Borland compilers. This has included removing the fudge introduced
1276        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1277        a warning about an unused variable.
1279    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1280        characters since release 4.0, because Perl (from release 5.004) does not.
1281        [Or at least, is documented not to: some releases seem to be in conflict
1282        with the documentation.] However, when a pattern was studied with
1283        pcre_study() and all its branches started with \s, PCRE still included VT
1284        as a possible starting character. Of course, this did no harm; it just
1285        caused an unnecessary match attempt.
1287    22. Removed a now-redundant internal flag bit that recorded the fact that case
1288        dependency changed within the pattern. This was once needed for "required
1289        byte" processing, but is no longer used. This recovers a now-scarce options
1290        bit. Also moved the least significant internal flag bit to the most-
1291        significant bit of the word, which was not previously used (hangover from
1292        the days when it was an int rather than a uint) to free up another bit for
1293        the future.
1295    23. Added support for CRLF line endings as well as CR and LF. As well as the
1296        default being selectable at build time, it can now be changed at runtime
1297        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1298        specify that it is scanning data with non-default line endings.
1300    24. Changed the definition of CXXLINK to make it agree with the definition of
1301        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1303    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1304        recursions. This makes a big different to stack usage for some patterns.
1306    26. If a subpattern containing a named recursion or subroutine reference such
1307        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1308        the space required for the compiled pattern went wrong and gave too small a
1309        value. Depending on the environment, this could lead to "Failed: internal
1310        error: code overflow at offset 49" or "glibc detected double free or
1311        corruption" errors.
1313    27. Applied patches from Google (a) to support the new newline modes and (b) to
1314        advance over multibyte UTF-8 characters in GlobalReplace.
1316    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1317        difference for some implementation of PCRE in some Windows version.
1319    29. Added some extra testing facilities to pcretest:
1321        \q<number>   in a data line sets the "match limit" value
1322        \Q<number>   in a data line sets the "match recursion limt" value
1323        -S <number>  sets the stack size, where <number> is in megabytes
1325        The -S option isn't available for Windows.
1328    Version 6.6 06-Feb-06
1329    ---------------------
1331     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1332        in pcreposix.h. I have copied the definition from pcre.h.
1334     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1335        because pcre.h is no longer a built file.
1337     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1338        not normally included in the compiled code.
1341    Version 6.5 01-Feb-06
1342    ---------------------
1344     1. When using the partial match feature with pcre_dfa_exec(), it was not
1345        anchoring the second and subsequent partial matches at the new starting
1346        point. This could lead to incorrect results. For example, with the pattern
1347        /1234/, partially matching against "123" and then "a4" gave a match.
1349     2. Changes to pcregrep:
1351        (a) All non-match returns from pcre_exec() were being treated as failures
1352            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1353            error message is output. Some extra information is given for the
1354            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1355            probably the only errors that are likely to be caused by users (by
1356            specifying a regex that has nested indefinite repeats, for instance).
1357            If there are more than 20 of these errors, pcregrep is abandoned.
1359        (b) A binary zero was treated as data while matching, but terminated the
1360            output line if it was written out. This has been fixed: binary zeroes
1361            are now no different to any other data bytes.
1363        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1364            used to set a locale for matching. The --locale=xxxx long option has
1365            been added (no short equivalent) to specify a locale explicitly on the
1366            pcregrep command, overriding the environment variables.
1368        (d) When -B was used with -n, some line numbers in the output were one less
1369            than they should have been.
1371        (e) Added the -o (--only-matching) option.
1373        (f) If -A or -C was used with -c (count only), some lines of context were
1374            accidentally printed for the final match.
1376        (g) Added the -H (--with-filename) option.
1378        (h) The combination of options -rh failed to suppress file names for files
1379            that were found from directory arguments.
1381        (i) Added the -D (--devices) and -d (--directories) options.
1383        (j) Added the -F (--fixed-strings) option.
1385        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1387        (l) Added the --colo(u)r option.
1389        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1390            is not present by default.
1392     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1393        items such as (?R) or (?1), when the recursion could match a number of
1394        alternatives. If it matched one of the alternatives, but subsequently,
1395        outside the recursion, there was a failure, the code tried to back up into
1396        the recursion. However, because of the way PCRE is implemented, this is not
1397        possible, and the result was an incorrect result from the match.
1399        In order to prevent this happening, the specification of recursion has
1400        been changed so that all such subpatterns are automatically treated as
1401        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1403     4. I had overlooked the fact that, in some locales, there are characters for
1404        which isalpha() is true but neither isupper() nor islower() are true. In
1405        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1406        and ordfeminine) are like this. This affected the treatment of \w and \W
1407        when they appeared in character classes, but not when they appeared outside
1408        a character class. The bit map for "word" characters is now created
1409        separately from the results of isalnum() instead of just taking it from the
1410        upper, lower, and digit maps. (Plus the underscore character, of course.)
1412     5. The above bug also affected the handling of POSIX character classes such as
1413        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1414        permanent tables. Instead, the bit maps for such a class were previously
1415        created as the appropriate unions of the upper, lower, and digit bitmaps.
1416        Now they are created by subtraction from the [[:word:]] class, which has
1417        its own bitmap.
1419     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1420        It is created by subtracting the vertical space characters (\x09, \x0a,
1421        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1422        subtraction was done in the overall bitmap for a character class, meaning
1423        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1424        be recognized. This bug has been fixed.
1426     7. Patches from the folks at Google:
1428          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1429          real life, but is still worth protecting against".
1431          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1432          regular expressions".
1434          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1435          have it.
1437          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1438          "configure" and the latter not, in order to fix a problem somebody had
1439          with compiling the Arg class on HP-UX.
1441          (e) Improve the error-handling of the C++ wrapper a little bit.
1443          (f) New tests for checking recursion limiting.
1445     8. The pcre_memmove() function, which is used only if the environment does not
1446        have a standard memmove() function (and is therefore rarely compiled),
1447        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1448        returning a result (though PCRE never actually uses the result).
1450     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1451        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1452        returned instead of calling malloc() with an overflowing number that would
1453        most likely cause subsequent chaos.
1455    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1457    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1458        with this option is matched, the nmatch and pmatch options of regexec() are
1459        ignored.
1461    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1462        provided in case anyone wants to the the POSIX interface with UTF-8
1463        strings.
1465    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1466        C++ linking (needed for some HP-UX environments).
1468    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1469        (unused parameter) and in the pcre_printint() function (omitted "default"
1470        switch label when the default is to do nothing).
1472    15. Added some code to make it possible, when PCRE is compiled as a C++
1473        library, to replace subject pointers for pcre_exec() with a smart pointer
1474        class, thus making it possible to process discontinuous strings.
1476    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1477        much the same function. They were added by different people who were trying
1478        to make PCRE easy to compile on non-Unix systems. It has been suggested
1479        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1480        for compiling on Windows systems. I have therefore replaced it with
1481        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1482        defaults to "extern" for C or "extern C" for C++, which works fine on
1483        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1484        SCOPE with something explicit in config.h. In addition:
1486        (a) pcreposix.h still had just "extern" instead of either of these macros;
1487            I have replaced it with PCRE_DATA_SCOPE.
1489        (b) Functions such as _pcre_xclass(), which are internal to the library,
1490            but external in the C sense, all had PCRE_EXPORT in their definitions.
1491            This is apparently wrong for the Windows case, so I have removed it.
1492            (It makes no difference on Unix-like systems.)
1494    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1495        of recursive calls to match(). This is different to MATCH_LIMIT because
1496        that limits the total number of calls to match(), not all of which increase
1497        the depth of recursion. Limiting the recursion depth limits the amount of
1498        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1499        when PCRE is compiled, and changed at run time. A patch from Google adds
1500        this functionality to the C++ interface.
1502    18. Changes to the handling of Unicode character properties:
1504        (a) Updated the table to Unicode 4.1.0.
1506        (b) Recognize characters that are not in the table as "Cn" (undefined).
1508        (c) I revised the way the table is implemented to a much improved format
1509            which includes recognition of ranges. It now supports the ranges that
1510            are defined in UnicodeData.txt, and it also amalgamates other
1511            characters into ranges. This has reduced the number of entries in the
1512            table from around 16,000 to around 3,000, thus reducing its size
1513            considerably. I realized I did not need to use a tree structure after
1514            all - a binary chop search is just as efficient. Having reduced the
1515            number of entries, I extended their size from 6 bytes to 8 bytes to
1516            allow for more data.
1518        (d) Added support for Unicode script names via properties such as \p{Han}.
1520    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1521        matching that character.
1523    20. When matching a repeated Unicode property with a minimum greater than zero,
1524        (for example \pL{2,}), PCRE could look past the end of the subject if it
1525        reached it while seeking the minimum number of characters. This could
1526        happen only if some of the characters were more than one byte long, because
1527        there is a check for at least the minimum number of bytes.
1529    21. Refactored the implementation of \p and \P so as to be more general, to
1530        allow for more different types of property in future. This has changed the
1531        compiled form incompatibly. Anybody with saved compiled patterns that use
1532        \p or \P will have to recompile them.
1534    22. Added "Any" and "L&" to the supported property types.
1536    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1537        but give a compile time error if the value is greater than 0xff.
1539    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1540        accidentally not being installed or uninstalled.
1542    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1543        made were to insert the current release number. This seemed silly, because
1544        it made things harder for people building PCRE on systems that don't run
1545        "configure". I have turned pcre.h into a distributed file, no longer built
1546        by "configure", with the version identification directly included. There is
1547        no longer a pcre.h.in file.
1549        However, this change necessitated a change to the pcre-config script as
1550        well. It is built from pcre-config.in, and one of the substitutions was the
1551        release number. I have updated configure.ac so that ./configure now finds
1552        the release number by grepping pcre.h.
1554    26. Added the ability to run the tests under valgrind.
1557  Version 6.4 05-Sep-05  Version 6.4 05-Sep-05
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