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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 393 by ph10, Tue Mar 17 21:47:54 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.9 xx-xxx-09
5    ---------------------
7    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
8        (pcretest), all targets were linked against these libraries. This included
9        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
10        libraries. This caused unwanted dependencies to be created. This problem
11        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
12        pcretest is linked with readline.
14    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
15        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
16        moved outside it again, because FALSE and TRUE are already defined in AIX,
17        but BOOL is not.
19    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
20        PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.
22    4.  The pcregrep documentation said spaces were inserted as well as colons (or
23        hyphens) following file names and line numbers when outputting matching
24        lines. This is not true; no spaces are inserted. I have also clarified the
25        wording for the --colour (or --color) option.
27    5.  In pcregrep, when --colour was used with -o, the list of matching strings
28        was not coloured; this is different to GNU grep, so I have changed it to be
29        the same.
31    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
32        each matching line was coloured. Now it goes on to look for further matches
33        of any of the test patterns, which is the same behaviour as GNU grep.
35    7.  A pattern that could match an empty string could cause pcregrep to loop; it
36        doesn't make sense to accept an empty string match in pcregrep, so I have
37        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
38        seems to be how GNU grep behaves.
40    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
41        start or after a newline", because the conditional assertion was not being
42        correctly handled. The rule now is that both the assertion and what follows
43        in the first alternative must satisfy the test.
45    9.  If auto-callout was enabled in a pattern with a conditional group, PCRE
46        could crash during matching.
48    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
49        used for matching.
51    11. Unicode property support in character classes was not working for
52        characters (bytes) greater than 127 when not in UTF-8 mode.
54    12. Added the -M command line option to pcretest.
56    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
58    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
60    16. Added comments and documentation about mis-use of no_arg in the C++
61        wrapper.
63    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
64        from Martin Jerabek that uses macro names for all relevant character and
65        string constants.
67    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
68        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
69        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
70        these, but not everybody uses configure.
73    Version 7.8 05-Sep-08
74    ---------------------
76    1.  Replaced UCP searching code with optimized version as implemented for Ad
77        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
78        stage table and inline lookup instead of a function, giving speed ups of 2
79        to 5 times on some simple patterns that I tested. Permission was given to
80        distribute the MultiStage2.py script that generates the tables (it's not in
81        the tarball, but is in the Subversion repository).
83    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
84        scripts.
86    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
87        a group with a zero qualifier. The result of the study could be incorrect,
88        or the function might crash, depending on the pattern.
90    4.  Caseless matching was not working for non-ASCII characters in back
91        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
92        It now works when Unicode Property Support is available.
94    5.  In pcretest, an escape such as \x{de} in the data was always generating
95        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
96        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
97        truncation.
99    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
101    7.  Added two (int) casts to pcregrep when printing the difference of two
102        pointers, in case they are 64-bit values.
104    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
105        test 2 if it fails.
107    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
108        and a #define of that name to empty if it is not externally set. This is to
109        allow users of MSVC to set it if necessary.
111    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
112        the convenience functions in the pcre_get.c source file.
114    11. An option change at the start of a pattern that had top-level alternatives
115        could cause overwriting and/or a crash. This command provoked a crash in
116        some environments:
118          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
120        This potential security problem was recorded as CVE-2008-2371.
122    12. For a pattern where the match had to start at the beginning or immediately
123        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
124        pcre_dfa_exec() could read past the end of the passed subject if there was
125        no match. To help with detecting such bugs (e.g. with valgrind), I modified
126        pcretest so that it places the subject at the end of its malloc-ed buffer.
128    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
129        exec() might read past the end of the data buffer in UTF-8 mode.
131    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
132        the data contained the byte 0x85 as part of a UTF-8 character within its
133        first line. This applied both to normal and DFA matching.
135    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
136        /^[^d]*?$/8 failed to match "abc".
138    16. Added a missing copyright notice to pcrecpp_internal.h.
140    17. Make it more clear in the documentation that values returned from
141        pcre_exec() in ovector are byte offsets, not character counts.
143    18. Tidied a few places to stop certain compilers from issuing warnings.
145    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
146        supplied by Stefan Weber. I made a further small update for 7.8 because
147        there is a change of source arrangements: the pcre_searchfuncs.c module is
148        replaced by pcre_ucd.c.
151    Version 7.7 07-May-08
152    ---------------------
154    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
155        a string to a long long, pretend we don't even have a long long." This is
156        done by checking for the strtoq, strtoll, and _strtoi64 functions.
158    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
159        pre-7.6 versions, which defined a global no_arg variable instead of putting
160        it in the RE class. (See also #8 below.)
162    3.  Remove a line of dead code, identified by coverity and reported by Nuno
163        Lopes.
165    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
167        (1) The include/exclude patterns were being applied to the whole pathnames
168            of files, instead of just to the final components.
170        (2) If there was more than one level of directory, the subdirectories were
171            skipped unless they satisfied the include/exclude conditions. This is
172            inconsistent with GNU grep (and could even be seen as contrary to the
173            pcregrep specification - which I improved to make it absolutely clear).
174            The action now is always to scan all levels of directory, and just
175            apply the include/exclude patterns to regular files.
177    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
178        --exclude_dir in the tests to avoid scanning .svn directories.
180    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
181        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
182        doesn't support NULs in patterns.
184    7.  Added some missing "const"s to declarations of static tables in
185        pcre_compile.c and pcre_dfa_exec.c.
187    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
188        caused by fix #2  above. (Subsequently also a second patch to fix the
189        first patch. And a third patch - this was a messy problem.)
191    9.  Applied Craig's patch to remove the use of push_back().
193    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
194        matching function regexec().
196    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
197        which, however, unlike Perl's \g{...}, are subroutine calls, not back
198        references. PCRE supports relative numbers with this syntax (I don't think
199        Oniguruma does).
201    12. Previously, a group with a zero repeat such as (...){0} was completely
202        omitted from the compiled regex. However, this means that if the group
203        was called as a subroutine from elsewhere in the pattern, things went wrong
204        (an internal error was given). Such groups are now left in the compiled
205        pattern, with a new opcode that causes them to be skipped at execution
206        time.
208    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
209        to the way PCRE behaves:
211        (a) A lone ] character is dis-allowed (Perl treats it as data).
213        (b) A back reference to an unmatched subpattern matches an empty string
214            (Perl fails the current match path).
216        (c) A data ] in a character class must be notated as \] because if the
217            first data character in a class is ], it defines an empty class. (In
218            Perl it is not possible to have an empty class.) The empty class []
219            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
220            The negative empty class [^] matches any one character, independently
221            of the DOTALL setting.
223    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
224        non-existent subpattern following a character class starting with ']' and
225        containing () gave an internal compiling error instead of "reference to
226        non-existent subpattern". Fortunately, when the pattern did exist, the
227        compiled code was correct. (When scanning forwards to check for the
228        existencd of the subpattern, it was treating the data ']' as terminating
229        the class, so got the count wrong. When actually compiling, the reference
230        was subsequently set up correctly.)
232    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
233        it was being rejected as not supported by pcre_dfa_exec(), even though
234        other assertions are supported. I have made pcre_dfa_exec() support
235        (*FAIL).
237    16. The implementation of 13c above involved the invention of a new opcode,
238        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
239        cannot be changed at match time, I realized I could make a small
240        improvement to matching performance by compiling OP_ALLANY instead of
241        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
242        on the OP_ANY path.
244    17. Compiling pcretest on Windows with readline support failed without the
245        following two fixes: (1) Make the unistd.h include conditional on
246        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
248    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
249        ncurses library to be included for pcretest when ReadLine support is
250        requested, but also to allow for it to be overridden. This patch came from
251        Daniel Bergström.
253    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
254        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
255        any errors with the current Unicode tables. Thanks to Peter Kankowski for
256        spotting this.
259    Version 7.6 28-Jan-08
260    ---------------------
262    1.  A character class containing a very large number of characters with
263        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
264        overflow.
266    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
267        HAVE_LONG_LONG is not defined.
269    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
270        bring them up to date and include new features. This patch includes:
272        - Fixed PH's badly added libz and libbz2 support.
273        - Fixed a problem with static linking.
274        - Added pcredemo. [But later removed - see 7 below.]
275        - Fixed dftables problem and added an option.
276        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
277            HAVE_LONG_LONG.
278        - Added readline support for pcretest.
279        - Added an listing of the option settings after cmake has run.
281    4.  A user submitted a patch to Makefile that makes it easy to create
282        "pcre.dll" under mingw when using Configure/Make. I added stuff to
283        Makefile.am that cause it to include this special target, without
284        affecting anything else. Note that the same mingw target plus all
285        the other distribution libraries and programs are now supported
286        when configuring with CMake (see 6 below) instead of with
287        Configure/Make.
289    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
290        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
291        exported in the Windows port". It has not yet been confirmed that the patch
292        solves the problem, but it does no harm.
294    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
295        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
296        with CMake, and also correct the comment about stack recursion.
298    7.  Remove the automatic building of pcredemo from the ./configure system and
299        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
300        of a program that users should build themselves after PCRE is installed, so
301        building it automatically is not really right. What is more, it gave
302        trouble in some build environments.
304    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
307    Version 7.5 10-Jan-08
308    ---------------------
310    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
311        values in parens when parsing an RE using the C++ wrapper."
313    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
314        Characters greater than 255 were excluded from the class instead of being
315        included.
317    3.  The same bug as (2) above applied to negated POSIX classes such as
318        [:^space:].
320    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
321        defined or documented. It seems to have been a typo for PCRE_STATIC, so
322        I have changed it.
324    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
325        first named subpattern) and a construct such as (?&a) would reference the
326        first named subpattern whose name started with "a" (in other words, the
327        length check was missing). Both these problems are fixed. "Subpattern name
328        expected" is now given for (?&) (a zero-length name), and this patch also
329        makes it give the same error for \k'' (previously it complained that that
330        was a reference to a non-existent subpattern).
332    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
333        this is right because (?- can be followed by option settings as well as by
334        digits. I have, however, made the messages clearer.
336    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
337        than the number used in the conditional) now cause a compile-time error.
338        This is actually not compatible with Perl, which accepts such patterns, but
339        treats the conditional as always being FALSE (as PCRE used to), but it
340        seems to me that giving a diagnostic is better.
342    8.  Change "alphameric" to the more common word "alphanumeric" in comments
343        and messages.
345    9.  Fix two occurrences of "backslash" in comments that should have been
346        "backspace".
348    10. Remove two redundant lines of code that can never be obeyed (their function
349        was moved elsewhere).
351    11. The program that makes PCRE's Unicode character property table had a bug
352        which caused it to generate incorrect table entries for sequences of
353        characters that have the same character type, but are in different scripts.
354        It amalgamated them into a single range, with the script of the first of
355        them. In other words, some characters were in the wrong script. There were
356        thirteen such cases, affecting characters in the following ranges:
358          U+002b0 - U+002c1
359          U+0060c - U+0060d
360          U+0061e - U+00612
361          U+0064b - U+0065e
362          U+0074d - U+0076d
363          U+01800 - U+01805
364          U+01d00 - U+01d77
365          U+01d9b - U+01dbf
366          U+0200b - U+0200f
367          U+030fc - U+030fe
368          U+03260 - U+0327f
369          U+0fb46 - U+0fbb1
370          U+10450 - U+1049d
372    12. The -o option (show only the matching part of a line) for pcregrep was not
373        compatible with GNU grep in that, if there was more than one match in a
374        line, it showed only the first of them. It now behaves in the same way as
375        GNU grep.
377    13. If the -o and -v options were combined for pcregrep, it printed a blank
378        line for every non-matching line. GNU grep prints nothing, and pcregrep now
379        does the same. The return code can be used to tell if there were any
380        non-matching lines.
382    14. Added --file-offsets and --line-offsets to pcregrep.
384    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
385        infinitely looping recursion. The bug was that positive lookaheads were not
386        being skipped when checking for a possible empty match (negative lookaheads
387        and both kinds of lookbehind were skipped).
389    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
390        inclusion of <windows.h> to before rather than after the definition of
391        INVALID_FILE_ATTRIBUTES (patch from David Byron).
393    17. Specifying a possessive quantifier with a specific limit for a Unicode
394        character property caused pcre_compile() to compile bad code, which led at
395        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
396        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
397        caused the error; without that there was no problem.
399    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
401    19. Added --enable-pcretest-libreadline.
403    20. In pcrecpp.cc, the variable 'count' was incremented twice in
404        RE::GlobalReplace(). As a result, the number of replacements returned was
405        double what it should be. I removed one of the increments, but Craig sent a
406        later patch that removed the other one (the right fix) and added unit tests
407        that check the return values (which was not done before).
409    21. Several CMake things:
411        (1) Arranged that, when cmake is used on Unix, the libraries end up with
412            the names libpcre and libpcreposix, not just pcre and pcreposix.
414        (2) The above change means that pcretest and pcregrep are now correctly
415            linked with the newly-built libraries, not previously installed ones.
419    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
420        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
421        UTF-8 newline character). The key issue is that the pattern starts .*;
422        this means that the match must be either at the beginning, or after a
423        newline. The bug was in the code for advancing after a failed match and
424        checking that the new position followed a newline. It was not taking
425        account of UTF-8 characters correctly.
427    23. PCRE was behaving differently from Perl in the way it recognized POSIX
428        character classes. PCRE was not treating the sequence [:...:] as a
429        character class unless the ... were all letters. Perl, however, seems to
430        allow any characters between [: and :], though of course it rejects as
431        unknown any "names" that contain non-letters, because all the known class
432        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
433        for example, whereas PCRE did not - it did not recognize a POSIX character
434        class. This seemed a bit dangerous, so the code has been changed to be
435        closer to Perl. The behaviour is not identical to Perl, because PCRE will
436        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
437        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
438        Perl does, and where it didn't before.
440    24. Rewrite so as to remove the single use of %n from pcregrep because in some
441        Windows environments %n is disabled by default.
444    Version 7.4 21-Sep-07
445    ---------------------
447    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
448        means that a class such as [\s] counted as "explicit reference to CR or
449        LF". That isn't really right - the whole point of the change was to try to
450        help when there was an actual mention of one of the two characters. So now
451        the change happens only if \r or \n (or a literal CR or LF) character is
452        encountered.
454    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
455        of both had grown to the point where there were only 3 bits left.
456        Fortunately, there was spare space in the data structure, and so I have
457        moved the internal flags into a new 16-bit field to free up more option
458        bits.
460    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
461        but did not set the internal JCHANGED flag - either of these is enough to
462        control the way the "get" function works - but the PCRE_INFO_JCHANGED
463        facility is supposed to tell if (?J) was ever used, so now (?J) at the
464        start sets both bits.
466    4.  Added options (at build time, compile time, exec time) to change \R from
467        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
469    5.  doc/pcresyntax.html was missing from the distribution.
471    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
472        compatibility, even though it is no longer used.
474    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
475        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
476        windows.h file is present (where different names are used). [This was
477        reversed later after testing - see 16 below.]
479    8.  Changed all #include <config.h> to #include "config.h". There were also
480        some further <pcre.h> cases that I changed to "pcre.h".
482    9.  When pcregrep was used with the --colour option, it missed the line ending
483        sequence off the lines that it output.
485    10. It was pointed out to me that arrays of string pointers cause lots of
486        relocations when a shared library is dynamically loaded. A technique of
487        using a single long string with a table of offsets can drastically reduce
488        these. I have refactored PCRE in four places to do this. The result is
489        dramatic:
491          Originally:                          290
492          After changing UCP table:            187
493          After changing error message table:   43
494          After changing table of "verbs"       36
495          After changing table of Posix names   22
497        Thanks to the folks working on Gregex for glib for this insight.
499    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
500        unicode-properties was also set.
502    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
504    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
505        checked only for CRLF.
507    14. Added casts to pcretest.c to avoid compiler warnings.
509    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
511    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
512        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
513        entirely. This removes changes made in 7 above.
515    17. The CMake files have been updated, and there is now more information about
516        building with CMake in the NON-UNIX-USE document.
519    Version 7.3 28-Aug-07
520    ---------------------
522     1. In the rejigging of the build system that eventually resulted in 7.1, the
523        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
524        brackets there is not right, since it causes compilers to look for an
525        installed pcre.h, not the version that is in the source that is being
526        compiled (which of course may be different). I have changed it back to:
528          #include "pcre.h"
530        I have a vague recollection that the change was concerned with compiling in
531        different directories, but in the new build system, that is taken care of
532        by the VPATH setting the Makefile.
534     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
535        when the subject happened to end in the byte 0x85 (e.g. if the last
536        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
537        characters but of course it shouldn't be taken as a newline when it is part
538        of another character. The bug was that, for an unlimited repeat of . in
539        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
540        characters when looking for a newline.
542     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
544     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
545        in debug output.
547     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
548        long printing in the pcrecpp unittest when running under MinGW.
550     6. ESC_K was left out of the EBCDIC table.
552     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
553        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
554        limit also applies to "virtual nesting" when a pattern is recursive, and in
555        this case 1000 isn't so big. I have been able to remove this limit at the
556        expense of backing off one optimization in certain circumstances. Normally,
557        when pcre_exec() would call its internal match() function recursively and
558        immediately return the result unconditionally, it uses a "tail recursion"
559        feature to save stack. However, when a subpattern that can match an empty
560        string has an unlimited repetition quantifier, it no longer makes this
561        optimization. That gives it a stack frame in which to save the data for
562        checking that an empty string has been matched. Previously this was taken
563        from the 1000-entry workspace that had been reserved. So now there is no
564        explicit limit, but more stack is used.
566     8. Applied Daniel's patches to solve problems with the import/export magic
567        syntax that is required for Windows, and which was going wrong for the
568        pcreposix and pcrecpp parts of the library. These were overlooked when this
569        problem was solved for the main library.
571     9. There were some crude static tests to avoid integer overflow when computing
572        the size of patterns that contain repeated groups with explicit upper
573        limits. As the maximum quantifier is 65535, the maximum group length was
574        set at 30,000 so that the product of these two numbers did not overflow a
575        32-bit integer. However, it turns out that people want to use groups that
576        are longer than 30,000 bytes (though not repeat them that many times).
577        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
578        made it possible to implement the integer overflow checks in a much more
579        dynamic way, which I have now done. The artificial limitation on group
580        length has been removed - we now have only the limit on the total length of
581        the compiled pattern, which depends on the LINK_SIZE setting.
583    10. Fixed a bug in the documentation for get/copy named substring when
584        duplicate names are permitted. If none of the named substrings are set, the
585        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
586        empty string.
588    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
589        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
590        because the ] is interpreted as the first data character and the
591        terminating ] is not found. PCRE has been made compatible with Perl in this
592        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
593        cause memory overwriting.
595    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
596        string has been matched (to stop an infinite loop). It was not recognizing
597        a conditional subpattern that could match an empty string if that
598        subpattern was within another subpattern. For example, it looped when
599        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
600        condition was not nested. This bug has been fixed.
602    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
603        past the start of the subject in the presence of bytes with the top bit
604        set, for example "\x8aBCD".
606    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
607        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
609    14. Optimized (?!) to (*FAIL).
611    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
612        This restricts code points to be within the range 0 to 0x10FFFF, excluding
613        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
614        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
615        does: it's just the validity check that is more restrictive.
617    16. Inserted checks for integer overflows during escape sequence (backslash)
618        processing, and also fixed erroneous offset values for syntax errors during
619        backslash processing.
621    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
622        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
624    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
625        caused an overrun.
627    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
628        something other than just ASCII characters) inside a group that had an
629        unlimited repeat caused a loop at compile time (while checking to see
630        whether the group could match an empty string).
632    20. Debugging a pattern containing \p or \P could cause a crash. For example,
633        [\P{Any}] did so. (Error in the code for printing property names.)
635    21. An orphan \E inside a character class could cause a crash.
637    22. A repeated capturing bracket such as (A)? could cause a wild memory
638        reference during compilation.
640    23. There are several functions in pcre_compile() that scan along a compiled
641        expression for various reasons (e.g. to see if it's fixed length for look
642        behind). There were bugs in these functions when a repeated \p or \P was
643        present in the pattern. These operators have additional parameters compared
644        with \d, etc, and these were not being taken into account when moving along
645        the compiled data. Specifically:
647        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
648            length.
650        (b) An item such as \pL+ within a repeated group could cause crashes or
651            loops.
653        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
654            "reference to non-existent subpattern" error.
656        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
658    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
659        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
661    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
663    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
664        character were causing crashes (broken optimization).
666    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
667        \p or \P) caused a compile-time loop.
669    28. More problems have arisen in unanchored patterns when CRLF is a valid line
670        break. For example, the unstudied pattern [\r\n]A does not match the string
671        "\r\nA" because change 7.0/46 below moves the current point on by two
672        characters after failing to match at the start. However, the pattern \nA
673        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
674        the same is true. There doesn't seem any very clean way out of this, but
675        what I have chosen to do makes the common cases work: PCRE now takes note
676        of whether there can be an explicit match for \r or \n anywhere in the
677        pattern, and if so, 7.0/46 no longer applies. As part of this change,
678        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
679        pattern has explicit CR or LF references.
681    29. Added (*CR) etc for changing newline setting at start of pattern.
684    Version 7.2 19-Jun-07
685    ---------------------
687     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
688        which is apparently normally available under Windows.
690     2. Re-jig the pcregrep tests with different newline settings in an attempt
691        to make them independent of the local environment's newline setting.
693     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
695     4. Some of the "internals" tests were previously cut out when the link size
696        was not 2, because the output contained actual offsets. The recent new
697        "Z" feature of pcretest means that these can be cut out, making the tests
698        usable with all link sizes.
700     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
701        stack recursion. This gives a massive performance boost under BSD, but just
702        a small improvement under Linux. However, it saves one field in the frame
703        in all cases.
705     6. Added more features from the forthcoming Perl 5.10:
707        (a) (?-n) (where n is a string of digits) is a relative subroutine or
708            recursion call. It refers to the nth most recently opened parentheses.
710        (b) (?+n) is also a relative subroutine call; it refers to the nth next
711            to be opened parentheses.
713        (c) Conditions that refer to capturing parentheses can be specified
714            relatively, for example, (?(-2)... or (?(+3)...
716        (d) \K resets the start of the current match so that everything before
717            is not part of it.
719        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
721        (f) \g{name} is another synonym - part of Perl 5.10's unification of
722            reference syntax.
724        (g) (?| introduces a group in which the numbering of parentheses in each
725            alternative starts with the same number.
727        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
729     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
732     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
733        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
734        for detecting groups that can match an empty string.
736     9. A pattern with a very large number of alternatives (more than several
737        hundred) was running out of internal workspace during the pre-compile
738        phase, where pcre_compile() figures out how much memory will be needed. A
739        bit of new cunning has reduced the workspace needed for groups with
740        alternatives. The 1000-alternative test pattern now uses 12 bytes of
741        workspace instead of running out of the 4096 that are available.
743    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
745    11. Applied patch from Google to remove an optimization that didn't quite work.
746        The report of the bug said:
748          pcrecpp::RE("a*").FullMatch("aaa") matches, while
749          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
750          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
752    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
753        it matched the wrong number of bytes.
756    Version 7.1 24-Apr-07
757    ---------------------
759     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
760        that is more "standard", making use of automake and other Autotools. There
761        is some re-arrangement of the files and adjustment of comments consequent
762        on this.
764     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
765        for recursive directory scanning broke on some systems because the files
766        are not scanned in any specific order and on different systems the order
767        was different. A call to "sort" has been inserted into RunGrepTest for the
768        approprate test as a short-term fix. In the longer term there may be an
769        alternative.
771     3. I had an email from Eric Raymond about problems translating some of PCRE's
772        man pages to HTML (despite the fact that I distribute HTML pages, some
773        people do their own conversions for various reasons). The problems
774        concerned the use of low-level troff macros .br and .in. I have therefore
775        removed all such uses from the man pages (some were redundant, some could
776        be replaced by .nf/.fi pairs). The 132html script that I use to generate
777        HTML has been updated to handle .nf/.fi and to complain if it encounters
778        .br or .in.
780     4. Updated comments in configure.ac that get placed in config.h.in and also
781        arranged for config.h to be included in the distribution, with the name
782        config.h.generic, for the benefit of those who have to compile without
783        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
785     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
786        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
787        makevp.bat for the current PCRE, using the additional files
788        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
790     6. A Windows user reported a minor discrepancy with test 2, which turned out
791        to be caused by a trailing space on an input line that had got lost in his
792        copy. The trailing space was an accident, so I've just removed it.
794     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
795        that is needed.
797     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
798        as "const" (a) because they are and (b) because it helps the PHP
799        maintainers who have recently made a script to detect big data structures
800        in the php code that should be moved to the .rodata section. I remembered
801        to update Builducptable as well, so it won't revert if ucptable.h is ever
802        re-created.
804     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
805        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
806        order to be able to cut out the UTF-8 tables in the latter when UTF-8
807        support is not required. This saves 1.5-2K of code, which is important in
808        some applications.
810        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
811        so as not to refer to the tables, even though these functions will never be
812        called when UTF-8 support is disabled. Otherwise there are problems with a
813        shared library.
815    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
817        (a) It was defining its arguments as char * instead of void *.
819        (b) It was assuming that all moves were upwards in memory; this was true
820            a long time ago when I wrote it, but is no longer the case.
822        The emulated memove() is provided for those environments that have neither
823        memmove() nor bcopy(). I didn't think anyone used it these days, but that
824        is clearly not the case, as these two bugs were recently reported.
826    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
827        and Detrail to create the HTML documentation, the .txt form of the man
828        pages, and it removes trailing spaces from listed files. It also creates
829        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
830        case, it wraps all the #defines with #ifndefs. This script should be run
831        before "make dist".
833    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
834        with Unicode property support.
836        (a) For a maximizing quantifier, if the two different cases of the
837            character were of different lengths in their UTF-8 codings (there are
838            some cases like this - I found 11), and the matching function had to
839            back up over a mixture of the two cases, it incorrectly assumed they
840            were both the same length.
842        (b) When PCRE was configured to use the heap rather than the stack for
843            recursion during matching, it was not correctly preserving the data for
844            the other case of a UTF-8 character when checking ahead for a match
845            while processing a minimizing repeat. If the check also involved
846            matching a wide character, but failed, corruption could cause an
847            erroneous result when trying to check for a repeat of the original
848            character.
850    13. Some tidying changes to the testing mechanism:
852        (a) The RunTest script now detects the internal link size and whether there
853            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
854            values substituted by "configure". (The RunGrepTest script already did
855            this for UTF-8.) The configure.ac script no longer substitutes the
856            relevant variables.
858        (b) The debugging options /B and /D in pcretest show the compiled bytecode
859            with length and offset values. This means that the output is different
860            for different internal link sizes. Test 2 is skipped for link sizes
861            other than 2 because of this, bypassing the problem. Unfortunately,
862            there was also a test in test 3 (the locale tests) that used /B and
863            failed for link sizes other than 2. Rather than cut the whole test out,
864            I have added a new /Z option to pcretest that replaces the length and
865            offset values with spaces. This is now used to make test 3 independent
866            of link size. (Test 2 will be tidied up later.)
868    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
869        segmentation fault instead of returning the appropriate error message.
871    15. In multiline mode when the newline sequence was set to "any", the pattern
872        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
873        This doesn't seem right; it now treats the CRLF combination as the line
874        ending, and so does not match in that case. It's only a pattern such as ^$
875        that would hit this one: something like ^ABC$ would have failed after \r
876        and then tried again after \r\n.
878    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
879        in an attempt to make files that differ only in their line terminators
880        compare equal. This works on Linux.
882    17. Under certain error circumstances pcregrep might try to free random memory
883        as it exited. This is now fixed, thanks to valgrind.
885    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
886        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
887        was because its rules for how to advance for /g after matching an empty
888        string at the end of a line did not allow for this case. They now check for
889        it specially.
891    20. pcretest is supposed to handle patterns and data of any length, by
892        extending its buffers when necessary. It was getting this wrong when the
893        buffer for a data line had to be extended.
895    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
896        CRLF as a newline sequence.
898    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
899        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
900        I have nevertheless tidied it up.
902    23. Added some casts to kill warnings from HP-UX ia64 compiler.
904    24. Added a man page for pcre-config.
907    Version 7.0 19-Dec-06
908    ---------------------
910     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
911        moving to gcc 4.1.1.
913     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
914        sys/time.h, which is documented as needed for this function. It doesn't
915        seem to matter on Linux, but it showed up on some releases of OS X.
917     3. It seems that there are systems where bytes whose values are greater than
918        127 match isprint() in the "C" locale. The "C" locale should be the
919        default when a C program starts up. In most systems, only ASCII printing
920        characters match isprint(). This difference caused the output from pcretest
921        to vary, making some of the tests fail. I have changed pcretest so that:
923        (a) When it is outputting text in the compiled version of a pattern, bytes
924            other than 32-126 are always shown as hex escapes.
926        (b) When it is outputting text that is a matched part of a subject string,
927            it does the same, unless a different locale has been set for the match
928            (using the /L modifier). In this case, it uses isprint() to decide.
930     4. Fixed a major bug that caused incorrect computation of the amount of memory
931        required for a compiled pattern when options that changed within the
932        pattern affected the logic of the preliminary scan that determines the
933        length. The relevant options are -x, and -i in UTF-8 mode. The result was
934        that the computed length was too small. The symptoms of this bug were
935        either the PCRE error "internal error: code overflow" from pcre_compile(),
936        or a glibc crash with a message such as "pcretest: free(): invalid next
937        size (fast)". Examples of patterns that provoked this bug (shown in
938        pcretest format) are:
940          /(?-x: )/x
941          /(?x)(?-x: \s*#\s*)/
942          /((?i)[\x{c0}])/8
943          /(?i:[\x{c0}])/8
945        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
946        is now done differently.
948     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
949        wrapper classes; (b) implement a new function in the C++ scanner that is
950        more efficient than the old way of doing things because it avoids levels of
951        recursion in the regex matching; (c) add a paragraph to the documentation
952        for the FullMatch() function.
954     6. The escape sequence \n was being treated as whatever was defined as
955        "newline". Not only was this contrary to the documentation, which states
956        that \n is character 10 (hex 0A), but it also went horribly wrong when
957        "newline" was defined as CRLF. This has been fixed.
959     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
960        was being set to -1 for the "end of line" case (supposedly a value that no
961        character can have). Though this value is never used (the check for end of
962        line is "zero bytes in current character"), it caused compiler complaints.
963        I've changed it to 0xffffffff.
965     8. In pcre_version.c, the version string was being built by a sequence of
966        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
967        string (as it is for production releases) called a macro with an empty
968        argument. The C standard says the result of this is undefined. The gcc
969        compiler treats it as an empty string (which was what was wanted) but it is
970        reported that Visual C gives an error. The source has been hacked around to
971        avoid this problem.
973     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
974        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
975        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
976        of them did).
978    10. Originally, pcretest opened its input and output without "b"; then I was
979        told that "b" was needed in some environments, so it was added for release
980        5.0 to both the input and output. (It makes no difference on Unix-like
981        systems.) Later I was told that it is wrong for the input on Windows. I've
982        now abstracted the modes into two macros, to make it easier to fiddle with
983        them, and removed "b" from the input mode under Windows.
985    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
987    12. Added -help and --help to pcretest as an official way of being reminded
988        of the options.
990    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
991        and pcrecpp.cc because they annoy compilers at high warning levels.
993    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
995    15. Fixed an occurrence of == in configure.ac that should have been = (shell
996        scripts are not C programs :-) and which was not noticed because it works
997        on Linux.
999    16. pcretest is supposed to handle any length of pattern and data line (as one
1000        line or as a continued sequence of lines) by extending its input buffer if
1001        necessary. This feature was broken for very long pattern lines, leading to
1002        a string of junk being passed to pcre_compile() if the pattern was longer
1003        than about 50K.
1005    17. I have done a major re-factoring of the way pcre_compile() computes the
1006        amount of memory needed for a compiled pattern. Previously, there was code
1007        that made a preliminary scan of the pattern in order to do this. That was
1008        OK when PCRE was new, but as the facilities have expanded, it has become
1009        harder and harder to keep it in step with the real compile phase, and there
1010        have been a number of bugs (see for example, 4 above). I have now found a
1011        cunning way of running the real compile function in a "fake" mode that
1012        enables it to compute how much memory it would need, while actually only
1013        ever using a few hundred bytes of working memory and without too many
1014        tests of the mode. This should make future maintenance and development
1015        easier. A side effect of this work is that the limit of 200 on the nesting
1016        depth of parentheses has been removed (though this was never a serious
1017        limitation, I suspect). However, there is a downside: pcre_compile() now
1018        runs more slowly than before (30% or more, depending on the pattern). I
1019        hope this isn't a big issue. There is no effect on runtime performance.
1021    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1022        newline (only possible for the last line of a file) and it was a
1023        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1025    19. Added additional timing features to pcretest. (1) The -tm option now times
1026        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1027        separate command line item, by a number that specifies the number of
1028        repeats to use when timing. The default is 50000; this gives better
1029        precision, but takes uncomfortably long for very large patterns.
1031    20. Extended pcre_study() to be more clever in cases where a branch of a
1032        subpattern has no definite first character. For example, (a*|b*)[cd] would
1033        previously give no result from pcre_study(). Now it recognizes that the
1034        first character must be a, b, c, or d.
1036    21. There was an incorrect error "recursive call could loop indefinitely" if
1037        a subpattern (or the entire pattern) that was being tested for matching an
1038        empty string contained only one non-empty item after a nested subpattern.
1039        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1040        incorrectly, because the \d was being skipped in the check.
1042    22. The pcretest program now has a new pattern option /B and a command line
1043        option -b, which is equivalent to adding /B to every pattern. This causes
1044        it to show the compiled bytecode, without the additional information that
1045        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1046        is the same as /B/I).
1048    23. A new optimization is now able automatically to treat some sequences such
1049        as a*b as a*+b. More specifically, if something simple (such as a character
1050        or a simple class like \d) has an unlimited quantifier, and is followed by
1051        something that cannot possibly match the quantified thing, the quantifier
1052        is automatically "possessified".
1054    24. A recursive reference to a subpattern whose number was greater than 39
1055        went wrong under certain circumstances in UTF-8 mode. This bug could also
1056        have affected the operation of pcre_study().
1058    25. Realized that a little bit of performance could be had by replacing
1059        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1061    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1063    27. Possessive quantifiers such as a++ were previously implemented by turning
1064        them into atomic groups such as ($>a+). Now they have their own opcodes,
1065        which improves performance. This includes the automatically created ones
1066        from 23 above.
1068    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1069        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1070        the first matched character to be a colon. This applied both to named and
1071        numbered groups.
1073    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1075    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1076        building PCRE on Windows easier, so I have included it in the distribution.
1078    31. There is now a check in pcretest against a ridiculously large number being
1079        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1080        loop, the loop is abandoned.
1082    32. Forward references to subpatterns in conditions such as (?(2)...) where
1083        subpattern 2 is defined later cause pcre_compile() to search forwards in
1084        the pattern for the relevant set of parentheses. This search went wrong
1085        when there were unescaped parentheses in a character class, parentheses
1086        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1088    33. "Subroutine" calls and backreferences were previously restricted to
1089        referencing subpatterns earlier in the regex. This restriction has now
1090        been removed.
1092    34. Added a number of extra features that are going to be in Perl 5.10. On the
1093        whole, these are just syntactic alternatives for features that PCRE had
1094        previously implemented using the Python syntax or my own invention. The
1095        other formats are all retained for compatibility.
1097        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1098            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1099            also .NET compatible.
1101        (b) A recursion or subroutine call to a named group can now be defined as
1102            (?&name) as well as (?P>name).
1104        (c) A backreference to a named group can now be defined as \k<name> or
1105            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1106            5.10, are also .NET compatible.
1108        (d) A conditional reference to a named group can now use the syntax
1109            (?(<name>) or (?('name') as well as (?(name).
1111        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1112            groups (named and numbered) that are never evaluated inline, but can be
1113            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1114            is always false. There may be only one alternative in such a group.
1116        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1117            as the simple (?(R). The condition is true only if the most recent
1118            recursion is that of the given number or name. It does not search out
1119            through the entire recursion stack.
1121        (g) The escape \gN or \g{N} has been added, where N is a positive or
1122            negative number, specifying an absolute or relative reference.
1124    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1125        some "unreachable code" warnings.
1127    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1128        things, this adds five new scripts.
1130    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1131        There were also incompatibilities regarding the handling of \Q..\E inside
1132        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1133        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1135    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1136        matches an empty string, and forcibly breaks the loop. There were bugs in
1137        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1138        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1139        separate and independent bugs (that affected different cases) have been
1140        fixed.
1142    39. Refactored the code to abolish the use of different opcodes for small
1143        capturing bracket numbers. This is a tidy that I avoided doing when I
1144        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1145        The new approach is not only tidier, it makes it possible to reduce the
1146        memory needed to fix the previous bug (38).
1148    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1149        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1150        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1151        mode.
1153    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1154        report.
1156    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1157        copy construction and assignment in the C++ wrapper.
1159    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1160        couple of bugs that could have given wrong results in the "--newline=crlf"
1161        case.
1163    44. Added a number of casts and did some reorganization of signed/unsigned int
1164        variables following suggestions from Dair Grant. Also renamed the variable
1165        "this" as "item" because it is a C++ keyword.
1167    45. Arranged for dftables to add
1169          #include "pcre_internal.h"
1171        to pcre_chartables.c because without it, gcc 4.x may remove the array
1172        definition from the final binary if PCRE is built into a static library and
1173        dead code stripping is activated.
1175    46. For an unanchored pattern, if a match attempt fails at the start of a
1176        newline sequence, and the newline setting is CRLF or ANY, and the next two
1177        characters are CRLF, advance by two characters instead of one.
1180    Version 6.7 04-Jul-06
1181    ---------------------
1183     1. In order to handle tests when input lines are enormously long, pcretest has
1184        been re-factored so that it automatically extends its buffers when
1185        necessary. The code is crude, but this _is_ just a test program. The
1186        default size has been increased from 32K to 50K.
1188     2. The code in pcre_study() was using the value of the re argument before
1189        testing it for NULL. (Of course, in any sensible call of the function, it
1190        won't be NULL.)
1192     3. The memmove() emulation function in pcre_internal.h, which is used on
1193        systems that lack both memmove() and bcopy() - that is, hardly ever -
1194        was missing a "static" storage class specifier.
1196     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1197        containing an extended class (one that cannot be represented by a bitmap
1198        because it contains high-valued characters or Unicode property items, e.g.
1199        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1200        pattern, but PCRE should not loop if you do not (it no longer does).
1201        [Detail: two cases were found: (a) a repeated subpattern containing an
1202        extended class; (b) a recursive reference to a subpattern that followed a
1203        previous extended class. It wasn't skipping over the extended class
1204        correctly when UTF-8 mode was not set.]
1206     5. A negated single-character class was not being recognized as fixed-length
1207        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1208        compile error "lookbehind assertion is not fixed length".
1210     6. The RunPerlTest auxiliary script was showing an unexpected difference
1211        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1212        write a Perl script that can interpret lines of an input file either as
1213        byte characters or as UTF-8, which is what "perltest" was being required to
1214        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1215        can't do is switch easily at run time between having the "use utf8;" pragma
1216        or not. In the end, I fudged it by using the RunPerlTest script to insert
1217        "use utf8;" explicitly for the UTF-8 tests.
1219     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1220        the end of the subject string, contrary to the documentation and to what
1221        Perl does. This was true of both matching functions. Now it matches only at
1222        the start of the subject and immediately after *internal* newlines.
1224     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1225        a pointer to an int instead of a pointer to an unsigned long int. This
1226        caused problems on 64-bit systems.
1228     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1229        instance of the 'standard' template library not being so standard".
1231    10. There was no check on the number of named subpatterns nor the maximum
1232        length of a subpattern name. The product of these values is used to compute
1233        the size of the memory block for a compiled pattern. By supplying a very
1234        long subpattern name and a large number of named subpatterns, the size
1235        computation could be caused to overflow. This is now prevented by limiting
1236        the length of names to 32 characters, and the number of named subpatterns
1237        to 10,000.
1239    11. Subpatterns that are repeated with specific counts have to be replicated in
1240        the compiled pattern. The size of memory for this was computed from the
1241        length of the subpattern and the repeat count. The latter is limited to
1242        65535, but there was no limit on the former, meaning that integer overflow
1243        could in principle occur. The compiled length of a repeated subpattern is
1244        now limited to 30,000 bytes in order to prevent this.
1246    12. Added the optional facility to have named substrings with the same name.
1248    13. Added the ability to use a named substring as a condition, using the
1249        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1250        are numbers (not recommended). Forward references are permitted.
1252    14. Added forward references in named backreferences (if you see what I mean).
1254    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1255        pattern could run off the end of the subject. For example, the pattern
1256        "(?s)(.{1,5})"8 did this with the subject "ab".
1258    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1259        PCRE_CASELESS was set when matching characters that were quantified with ?
1260        or *.
1262    17. A character class other than a single negated character that had a minimum
1263        but no maximum quantifier - for example [ab]{6,} - was not handled
1264        correctly by pce_dfa_exec(). It would match only one character.
1266    18. A valid (though odd) pattern that looked like a POSIX character
1267        class but used an invalid character after [ (for example [[,abc,]]) caused
1268        pcre_compile() to give the error "Failed: internal error: code overflow" or
1269        in some cases to crash with a glibc free() error. This could even happen if
1270        the pattern terminated after [[ but there just happened to be a sequence of
1271        letters, a binary zero, and a closing ] in the memory that followed.
1273    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1274        over the years. Originally (before any Unicode support), just the bottom 8
1275        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1276        output from "man perlunicode" includes this:
1278          The regular expression compiler produces polymorphic opcodes.  That
1279          is, the pattern adapts to the data and automatically switches to
1280          the Unicode character scheme when presented with Unicode data--or
1281          instead uses a traditional byte scheme when presented with byte
1282          data.
1284        Sadly, a wide octal escape does not cause a switch, and in a string with
1285        no other multibyte characters, these octal escapes are treated as before.
1286        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1287        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1288        Unicode string.
1290        I have not perpetrated such confusion in PCRE. Up till now, it took just
1291        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1292        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1293        translate to the appropriate multibyte character.
1295    29. Applied some refactoring to reduce the number of warnings from Microsoft
1296        and Borland compilers. This has included removing the fudge introduced
1297        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1298        a warning about an unused variable.
1300    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1301        characters since release 4.0, because Perl (from release 5.004) does not.
1302        [Or at least, is documented not to: some releases seem to be in conflict
1303        with the documentation.] However, when a pattern was studied with
1304        pcre_study() and all its branches started with \s, PCRE still included VT
1305        as a possible starting character. Of course, this did no harm; it just
1306        caused an unnecessary match attempt.
1308    22. Removed a now-redundant internal flag bit that recorded the fact that case
1309        dependency changed within the pattern. This was once needed for "required
1310        byte" processing, but is no longer used. This recovers a now-scarce options
1311        bit. Also moved the least significant internal flag bit to the most-
1312        significant bit of the word, which was not previously used (hangover from
1313        the days when it was an int rather than a uint) to free up another bit for
1314        the future.
1316    23. Added support for CRLF line endings as well as CR and LF. As well as the
1317        default being selectable at build time, it can now be changed at runtime
1318        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1319        specify that it is scanning data with non-default line endings.
1321    24. Changed the definition of CXXLINK to make it agree with the definition of
1322        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1324    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1325        recursions. This makes a big different to stack usage for some patterns.
1327    26. If a subpattern containing a named recursion or subroutine reference such
1328        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1329        the space required for the compiled pattern went wrong and gave too small a
1330        value. Depending on the environment, this could lead to "Failed: internal
1331        error: code overflow at offset 49" or "glibc detected double free or
1332        corruption" errors.
1334    27. Applied patches from Google (a) to support the new newline modes and (b) to
1335        advance over multibyte UTF-8 characters in GlobalReplace.
1337    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1338        difference for some implementation of PCRE in some Windows version.
1340    29. Added some extra testing facilities to pcretest:
1342        \q<number>   in a data line sets the "match limit" value
1343        \Q<number>   in a data line sets the "match recursion limt" value
1344        -S <number>  sets the stack size, where <number> is in megabytes
1346        The -S option isn't available for Windows.
1349    Version 6.6 06-Feb-06
1350    ---------------------
1352     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1353        in pcreposix.h. I have copied the definition from pcre.h.
1355     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1356        because pcre.h is no longer a built file.
1358     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1359        not normally included in the compiled code.
1362    Version 6.5 01-Feb-06
1363    ---------------------
1365     1. When using the partial match feature with pcre_dfa_exec(), it was not
1366        anchoring the second and subsequent partial matches at the new starting
1367        point. This could lead to incorrect results. For example, with the pattern
1368        /1234/, partially matching against "123" and then "a4" gave a match.
1370     2. Changes to pcregrep:
1372        (a) All non-match returns from pcre_exec() were being treated as failures
1373            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1374            error message is output. Some extra information is given for the
1375            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1376            probably the only errors that are likely to be caused by users (by
1377            specifying a regex that has nested indefinite repeats, for instance).
1378            If there are more than 20 of these errors, pcregrep is abandoned.
1380        (b) A binary zero was treated as data while matching, but terminated the
1381            output line if it was written out. This has been fixed: binary zeroes
1382            are now no different to any other data bytes.
1384        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1385            used to set a locale for matching. The --locale=xxxx long option has
1386            been added (no short equivalent) to specify a locale explicitly on the
1387            pcregrep command, overriding the environment variables.
1389        (d) When -B was used with -n, some line numbers in the output were one less
1390            than they should have been.
1392        (e) Added the -o (--only-matching) option.
1394        (f) If -A or -C was used with -c (count only), some lines of context were
1395            accidentally printed for the final match.
1397        (g) Added the -H (--with-filename) option.
1399        (h) The combination of options -rh failed to suppress file names for files
1400            that were found from directory arguments.
1402        (i) Added the -D (--devices) and -d (--directories) options.
1404        (j) Added the -F (--fixed-strings) option.
1406        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1408        (l) Added the --colo(u)r option.
1410        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1411            is not present by default.
1413     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1414        items such as (?R) or (?1), when the recursion could match a number of
1415        alternatives. If it matched one of the alternatives, but subsequently,
1416        outside the recursion, there was a failure, the code tried to back up into
1417        the recursion. However, because of the way PCRE is implemented, this is not
1418        possible, and the result was an incorrect result from the match.
1420        In order to prevent this happening, the specification of recursion has
1421        been changed so that all such subpatterns are automatically treated as
1422        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1424     4. I had overlooked the fact that, in some locales, there are characters for
1425        which isalpha() is true but neither isupper() nor islower() are true. In
1426        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1427        and ordfeminine) are like this. This affected the treatment of \w and \W
1428        when they appeared in character classes, but not when they appeared outside
1429        a character class. The bit map for "word" characters is now created
1430        separately from the results of isalnum() instead of just taking it from the
1431        upper, lower, and digit maps. (Plus the underscore character, of course.)
1433     5. The above bug also affected the handling of POSIX character classes such as
1434        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1435        permanent tables. Instead, the bit maps for such a class were previously
1436        created as the appropriate unions of the upper, lower, and digit bitmaps.
1437        Now they are created by subtraction from the [[:word:]] class, which has
1438        its own bitmap.
1440     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1441        It is created by subtracting the vertical space characters (\x09, \x0a,
1442        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1443        subtraction was done in the overall bitmap for a character class, meaning
1444        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1445        be recognized. This bug has been fixed.
1447     7. Patches from the folks at Google:
1449          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1450          real life, but is still worth protecting against".
1452          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1453          regular expressions".
1455          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1456          have it.
1458          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1459          "configure" and the latter not, in order to fix a problem somebody had
1460          with compiling the Arg class on HP-UX.
1462          (e) Improve the error-handling of the C++ wrapper a little bit.
1464          (f) New tests for checking recursion limiting.
1466     8. The pcre_memmove() function, which is used only if the environment does not
1467        have a standard memmove() function (and is therefore rarely compiled),
1468        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1469        returning a result (though PCRE never actually uses the result).
1471     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1472        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1473        returned instead of calling malloc() with an overflowing number that would
1474        most likely cause subsequent chaos.
1476    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1478    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1479        with this option is matched, the nmatch and pmatch options of regexec() are
1480        ignored.
1482    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1483        provided in case anyone wants to the the POSIX interface with UTF-8
1484        strings.
1486    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1487        C++ linking (needed for some HP-UX environments).
1489    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1490        (unused parameter) and in the pcre_printint() function (omitted "default"
1491        switch label when the default is to do nothing).
1493    15. Added some code to make it possible, when PCRE is compiled as a C++
1494        library, to replace subject pointers for pcre_exec() with a smart pointer
1495        class, thus making it possible to process discontinuous strings.
1497    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1498        much the same function. They were added by different people who were trying
1499        to make PCRE easy to compile on non-Unix systems. It has been suggested
1500        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1501        for compiling on Windows systems. I have therefore replaced it with
1502        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1503        defaults to "extern" for C or "extern C" for C++, which works fine on
1504        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1505        SCOPE with something explicit in config.h. In addition:
1507        (a) pcreposix.h still had just "extern" instead of either of these macros;
1508            I have replaced it with PCRE_DATA_SCOPE.
1510        (b) Functions such as _pcre_xclass(), which are internal to the library,
1511            but external in the C sense, all had PCRE_EXPORT in their definitions.
1512            This is apparently wrong for the Windows case, so I have removed it.
1513            (It makes no difference on Unix-like systems.)
1515    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1516        of recursive calls to match(). This is different to MATCH_LIMIT because
1517        that limits the total number of calls to match(), not all of which increase
1518        the depth of recursion. Limiting the recursion depth limits the amount of
1519        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1520        when PCRE is compiled, and changed at run time. A patch from Google adds
1521        this functionality to the C++ interface.
1523    18. Changes to the handling of Unicode character properties:
1525        (a) Updated the table to Unicode 4.1.0.
1527        (b) Recognize characters that are not in the table as "Cn" (undefined).
1529        (c) I revised the way the table is implemented to a much improved format
1530            which includes recognition of ranges. It now supports the ranges that
1531            are defined in UnicodeData.txt, and it also amalgamates other
1532            characters into ranges. This has reduced the number of entries in the
1533            table from around 16,000 to around 3,000, thus reducing its size
1534            considerably. I realized I did not need to use a tree structure after
1535            all - a binary chop search is just as efficient. Having reduced the
1536            number of entries, I extended their size from 6 bytes to 8 bytes to
1537            allow for more data.
1539        (d) Added support for Unicode script names via properties such as \p{Han}.
1541    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1542        matching that character.
1544    20. When matching a repeated Unicode property with a minimum greater than zero,
1545        (for example \pL{2,}), PCRE could look past the end of the subject if it
1546        reached it while seeking the minimum number of characters. This could
1547        happen only if some of the characters were more than one byte long, because
1548        there is a check for at least the minimum number of bytes.
1550    21. Refactored the implementation of \p and \P so as to be more general, to
1551        allow for more different types of property in future. This has changed the
1552        compiled form incompatibly. Anybody with saved compiled patterns that use
1553        \p or \P will have to recompile them.
1555    22. Added "Any" and "L&" to the supported property types.
1557    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1558        but give a compile time error if the value is greater than 0xff.
1560    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1561        accidentally not being installed or uninstalled.
1563    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1564        made were to insert the current release number. This seemed silly, because
1565        it made things harder for people building PCRE on systems that don't run
1566        "configure". I have turned pcre.h into a distributed file, no longer built
1567        by "configure", with the version identification directly included. There is
1568        no longer a pcre.h.in file.
1570        However, this change necessitated a change to the pcre-config script as
1571        well. It is built from pcre-config.in, and one of the substitutions was the
1572        release number. I have updated configure.ac so that ./configure now finds
1573        the release number by grepping pcre.h.
1575    26. Added the ability to run the tests under valgrind.
1578    Version 6.4 05-Sep-05
1579    ---------------------
1581     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1582        "--" to be printed when multiple files were scanned, even when none of the
1583        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1584        consider it to be a bug, and have restored the previous behaviour.
1586     2. A couple of code tidies to get rid of compiler warnings.
1588     3. The pcretest program used to cheat by referring to symbols in the library
1589        whose names begin with _pcre_. These are internal symbols that are not
1590        really supposed to be visible externally, and in some environments it is
1591        possible to suppress them. The cheating is now confined to including
1592        certain files from the library's source, which is a bit cleaner.
1594     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1595        file's purpose clearer.
1597     5. Reorganized pcre_ucp_findchar().
1600    Version 6.3 15-Aug-05
1601    ---------------------
1603     1. The file libpcre.pc.in did not have general read permission in the tarball.
1605     2. There were some problems when building without C++ support:
1607        (a) If C++ support was not built, "make install" and "make test" still
1608            tried to test it.
1610        (b) There were problems when the value of CXX was explicitly set. Some
1611            changes have been made to try to fix these, and ...
1613        (c) --disable-cpp can now be used to explicitly disable C++ support.
1615        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1616            backslash in a target when C++ was disabled. This confuses some
1617            versions of "make", apparently. Using an intermediate variable solves
1618            this. (Same for CPP_LOBJ.)
1620     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1621        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1622        necessary on certain architectures.
1624     4. Added a setting of -export-symbols-regex to the link command to remove
1625        those symbols that are exported in the C sense, but actually are local
1626        within the library, and not documented. Their names all begin with
1627        "_pcre_". This is not a perfect job, because (a) we have to except some
1628        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1629        available (and never for static libraries). I have made a note to try to
1630        find a way round (a) in the future.
1633    Version 6.2 01-Aug-05
1634    ---------------------
1636     1. There was no test for integer overflow of quantifier values. A construction
1637        such as {1111111111111111} would give undefined results. What is worse, if
1638        a minimum quantifier for a parenthesized subpattern overflowed and became
1639        negative, the calculation of the memory size went wrong. This could have
1640        led to memory overwriting.
1642     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1644     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1645        operating environments where this matters.
1647     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1648        PCRE options from within the C++ wrapper.
1650     5. Named capturing subpatterns were not being correctly counted when a pattern
1651        was compiled. This caused two problems: (a) If there were more than 100
1652        such subpatterns, the calculation of the memory needed for the whole
1653        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1654        back references of the form \12, where the number was greater than 9, were
1655        not recognized as back references, even though there were sufficient
1656        previous subpatterns.
1658     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1659        versions of gcc, e.g. 2.95.4.
1662    Version 6.1 21-Jun-05
1663    ---------------------
1665     1. There was one reference to the variable "posix" in pcretest.c that was not
1666        surrounded by "#if !defined NOPOSIX".
1668     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1669        the cross-check on the old pcre_info() function, for the benefit of the
1670        cut-down version of PCRE that is currently imported into Exim.
1672     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1673        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1674        patterns that start (?i) but I don't think that matters. The use of (?i) is
1675        just an example; this all applies to the other options as well.
1677     4. Since libtool seems to echo the compile commands it is issuing, the output
1678        from "make" can be reduced a bit by putting "@" in front of each libtool
1679        compile command.
1681     5. Patch from the folks at Google for configure.in to be a bit more thorough
1682        in checking for a suitable C++ installation before trying to compile the
1683        C++ stuff. This should fix a reported problem when a compiler was present,
1684        but no suitable headers.
1686     6. The man pages all had just "PCRE" as their title. I have changed them to
1687        be the relevant file name. I have also arranged that these names are
1688        retained in the file doc/pcre.txt, which is a concatenation in text format
1689        of all the man pages except the little individual ones for each function.
1691     7. The NON-UNIX-USE file had not been updated for the different set of source
1692        files that come with release 6. I also added a few comments about the C++
1693        wrapper.
1696  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
1697  ---------------------  ---------------------

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