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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 343 by ph10, Mon Apr 21 16:30:37 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.7 05-Mar-08
5    ---------------------
7    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
8        a string to a long long, pretend we don't even have a long long." This is
9        done by checking for the strtoq, strtoll, and _strtoi64 functions.
11    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
12        pre-7.6 versions, which defined a global no_arg variable instead of putting
13        it in the RE class. (See also #8 below.)
15    3.  Remove a line of dead code, identified by coverity and reported by Nuno
16        Lopes.
18    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
20        (1) The include/exclude patterns were being applied to the whole pathnames
21            of files, instead of just to the final components.
23        (2) If there was more than one level of directory, the subdirectories were
24            skipped unless they satisfied the include/exclude conditions. This is
25            inconsistent with GNU grep (and could even be seen as contrary to the
26            pcregrep specification - which I improved to make it absolutely clear).
27            The action now is always to scan all levels of directory, and just
28            apply the include/exclude patterns to regular files.
30    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
31        --exclude_dir in the tests to avoid scanning .svn directories.
33    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
34        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
35        doesn't support NULs in patterns.
37    7.  Added some missing "const"s to declarations of static tables in
38        pcre_compile.c and pcre_dfa_exec.c.
40    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
41        caused by fix #2  above. (Subsequently also a second patch to fix the
42        first patch. And a third patch - this was a messy problem.)
44    9.  Applied Craig's patch to remove the use of push_back().
46    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
47        matching function regexec().
49    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
50        which, however, unlike Perl's \g{...}, are subroutine calls, not back
51        references. PCRE supports relative numbers with this syntax (I don't think
52        Oniguruma does).
54    12. Previously, a group with a zero repeat such as (...){0} was completely
55        omitted from the compiled regex. However, this means that if the group
56        was called as a subroutine from elsewhere in the pattern, things went wrong
57        (an internal error was given). Such groups are now left in the compiled
58        pattern, with a new opcode that causes them to be skipped at execution
59        time.
61    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
62        to the way PCRE behaves:
64        (a) A lone ] character is dis-allowed (Perl treats it as data).
66        (b) A back reference to an unmatched subpattern matches an empty string
67            (Perl fails the current match path).
69        (c) A data ] in a character class must be notated as \] because if the
70            first data character in a class is ], it defines an empty class. (In
71            Perl it is not possible to have an empty class.) The empty class []
72            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
73            The negative empty class [^] matches any one character, independently
74            of the DOTALL setting.
76    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
77        non-existent subpattern following a character class starting with ']' and
78        containing () gave an internal compiling error instead of "reference to
79        non-existent subpattern". Fortunately, when the pattern did exist, the
80        compiled code was correct. (When scanning forwards to check for the
81        existencd of the subpattern, it was treating the data ']' as terminating
82        the class, so got the count wrong. When actually compiling, the reference
83        was subsequently set up correctly.)
85    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
86        it was being rejected as not supported by pcre_dfa_exec(), even though
87        other assertions are supported. I have made pcre_dfa_exec() support
88        (*FAIL).
90    16. The implementation of 13c above involved the invention of a new opcode,
91        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
92        cannot be changed at match time, I realized I could make a small
93        improvement to matching performance by compiling OP_ALLANY instead of
94        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
95        on the OP_ANY path.
97    17. Compiling pcretest on Windows with readline support failed without the
98        following two fixes: (1) Make the unistd.h include conditional on
99        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
102    Version 7.6 28-Jan-08
103    ---------------------
105    1.  A character class containing a very large number of characters with
106        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
107        overflow.
109    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
110        HAVE_LONG_LONG is not defined.
112    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
113        bring them up to date and include new features. This patch includes:
115        - Fixed PH's badly added libz and libbz2 support.
116        - Fixed a problem with static linking.
117        - Added pcredemo. [But later removed - see 7 below.]
118        - Fixed dftables problem and added an option.
119        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
120            HAVE_LONG_LONG.
121        - Added readline support for pcretest.
122        - Added an listing of the option settings after cmake has run.
124    4.  A user submitted a patch to Makefile that makes it easy to create
125        "pcre.dll" under mingw when using Configure/Make. I added stuff to
126        Makefile.am that cause it to include this special target, without
127        affecting anything else. Note that the same mingw target plus all
128        the other distribution libraries and programs are now supported
129        when configuring with CMake (see 6 below) instead of with
130        Configure/Make.
132    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
133        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
134        exported in the Windows port". It has not yet been confirmed that the patch
135        solves the problem, but it does no harm.
137    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
138        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
139        with CMake, and also correct the comment about stack recursion.
141    7.  Remove the automatic building of pcredemo from the ./configure system and
142        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
143        of a program that users should build themselves after PCRE is installed, so
144        building it automatically is not really right. What is more, it gave
145        trouble in some build environments.
147    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
150    Version 7.5 10-Jan-08
151    ---------------------
153    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
154        values in parens when parsing an RE using the C++ wrapper."
156    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
157        Characters greater than 255 were excluded from the class instead of being
158        included.
160    3.  The same bug as (2) above applied to negated POSIX classes such as
161        [:^space:].
163    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
164        defined or documented. It seems to have been a typo for PCRE_STATIC, so
165        I have changed it.
167    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
168        first named subpattern) and a construct such as (?&a) would reference the
169        first named subpattern whose name started with "a" (in other words, the
170        length check was missing). Both these problems are fixed. "Subpattern name
171        expected" is now given for (?&) (a zero-length name), and this patch also
172        makes it give the same error for \k'' (previously it complained that that
173        was a reference to a non-existent subpattern).
175    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
176        this is right because (?- can be followed by option settings as well as by
177        digits. I have, however, made the messages clearer.
179    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
180        than the number used in the conditional) now cause a compile-time error.
181        This is actually not compatible with Perl, which accepts such patterns, but
182        treats the conditional as always being FALSE (as PCRE used to), but it
183        seems to me that giving a diagnostic is better.
185    8.  Change "alphameric" to the more common word "alphanumeric" in comments
186        and messages.
188    9.  Fix two occurrences of "backslash" in comments that should have been
189        "backspace".
191    10. Remove two redundant lines of code that can never be obeyed (their function
192        was moved elsewhere).
194    11. The program that makes PCRE's Unicode character property table had a bug
195        which caused it to generate incorrect table entries for sequences of
196        characters that have the same character type, but are in different scripts.
197        It amalgamated them into a single range, with the script of the first of
198        them. In other words, some characters were in the wrong script. There were
199        thirteen such cases, affecting characters in the following ranges:
201          U+002b0 - U+002c1
202          U+0060c - U+0060d
203          U+0061e - U+00612
204          U+0064b - U+0065e
205          U+0074d - U+0076d
206          U+01800 - U+01805
207          U+01d00 - U+01d77
208          U+01d9b - U+01dbf
209          U+0200b - U+0200f
210          U+030fc - U+030fe
211          U+03260 - U+0327f
212          U+0fb46 - U+0fbb1
213          U+10450 - U+1049d
215    12. The -o option (show only the matching part of a line) for pcregrep was not
216        compatible with GNU grep in that, if there was more than one match in a
217        line, it showed only the first of them. It now behaves in the same way as
218        GNU grep.
220    13. If the -o and -v options were combined for pcregrep, it printed a blank
221        line for every non-matching line. GNU grep prints nothing, and pcregrep now
222        does the same. The return code can be used to tell if there were any
223        non-matching lines.
225    14. Added --file-offsets and --line-offsets to pcregrep.
227    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
228        infinitely looping recursion. The bug was that positive lookaheads were not
229        being skipped when checking for a possible empty match (negative lookaheads
230        and both kinds of lookbehind were skipped).
232    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
233        inclusion of <windows.h> to before rather than after the definition of
234        INVALID_FILE_ATTRIBUTES (patch from David Byron).
236    17. Specifying a possessive quantifier with a specific limit for a Unicode
237        character property caused pcre_compile() to compile bad code, which led at
238        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
239        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
240        caused the error; without that there was no problem.
242    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
244    19. Added --enable-pcretest-libreadline.
246    20. In pcrecpp.cc, the variable 'count' was incremented twice in
247        RE::GlobalReplace(). As a result, the number of replacements returned was
248        double what it should be. I removed one of the increments, but Craig sent a
249        later patch that removed the other one (the right fix) and added unit tests
250        that check the return values (which was not done before).
252    21. Several CMake things:
254        (1) Arranged that, when cmake is used on Unix, the libraries end up with
255            the names libpcre and libpcreposix, not just pcre and pcreposix.
257        (2) The above change means that pcretest and pcregrep are now correctly
258            linked with the newly-built libraries, not previously installed ones.
262    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
263        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
264        UTF-8 newline character). The key issue is that the pattern starts .*;
265        this means that the match must be either at the beginning, or after a
266        newline. The bug was in the code for advancing after a failed match and
267        checking that the new position followed a newline. It was not taking
268        account of UTF-8 characters correctly.
270    23. PCRE was behaving differently from Perl in the way it recognized POSIX
271        character classes. PCRE was not treating the sequence [:...:] as a
272        character class unless the ... were all letters. Perl, however, seems to
273        allow any characters between [: and :], though of course it rejects as
274        unknown any "names" that contain non-letters, because all the known class
275        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
276        for example, whereas PCRE did not - it did not recognize a POSIX character
277        class. This seemed a bit dangerous, so the code has been changed to be
278        closer to Perl. The behaviour is not identical to Perl, because PCRE will
279        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
280        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
281        Perl does, and where it didn't before.
283    24. Rewrite so as to remove the single use of %n from pcregrep because in some
284        Windows environments %n is disabled by default.
287    Version 7.4 21-Sep-07
288    ---------------------
290    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
291        means that a class such as [\s] counted as "explicit reference to CR or
292        LF". That isn't really right - the whole point of the change was to try to
293        help when there was an actual mention of one of the two characters. So now
294        the change happens only if \r or \n (or a literal CR or LF) character is
295        encountered.
297    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
298        of both had grown to the point where there were only 3 bits left.
299        Fortunately, there was spare space in the data structure, and so I have
300        moved the internal flags into a new 16-bit field to free up more option
301        bits.
303    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
304        but did not set the internal JCHANGED flag - either of these is enough to
305        control the way the "get" function works - but the PCRE_INFO_JCHANGED
306        facility is supposed to tell if (?J) was ever used, so now (?J) at the
307        start sets both bits.
309    4.  Added options (at build time, compile time, exec time) to change \R from
310        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
312    5.  doc/pcresyntax.html was missing from the distribution.
314    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
315        compatibility, even though it is no longer used.
317    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
318        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
319        windows.h file is present (where different names are used). [This was
320        reversed later after testing - see 16 below.]
322    8.  Changed all #include <config.h> to #include "config.h". There were also
323        some further <pcre.h> cases that I changed to "pcre.h".
325    9.  When pcregrep was used with the --colour option, it missed the line ending
326        sequence off the lines that it output.
328    10. It was pointed out to me that arrays of string pointers cause lots of
329        relocations when a shared library is dynamically loaded. A technique of
330        using a single long string with a table of offsets can drastically reduce
331        these. I have refactored PCRE in four places to do this. The result is
332        dramatic:
334          Originally:                          290
335          After changing UCP table:            187
336          After changing error message table:   43
337          After changing table of "verbs"       36
338          After changing table of Posix names   22
340        Thanks to the folks working on Gregex for glib for this insight.
342    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
343        unicode-properties was also set.
345    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
347    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
348        checked only for CRLF.
350    14. Added casts to pcretest.c to avoid compiler warnings.
352    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
354    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
355        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
356        entirely. This removes changes made in 7 above.
358    17. The CMake files have been updated, and there is now more information about
359        building with CMake in the NON-UNIX-USE document.
362    Version 7.3 28-Aug-07
363    ---------------------
365     1. In the rejigging of the build system that eventually resulted in 7.1, the
366        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
367        brackets there is not right, since it causes compilers to look for an
368        installed pcre.h, not the version that is in the source that is being
369        compiled (which of course may be different). I have changed it back to:
371          #include "pcre.h"
373        I have a vague recollection that the change was concerned with compiling in
374        different directories, but in the new build system, that is taken care of
375        by the VPATH setting the Makefile.
377     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
378        when the subject happened to end in the byte 0x85 (e.g. if the last
379        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
380        characters but of course it shouldn't be taken as a newline when it is part
381        of another character. The bug was that, for an unlimited repeat of . in
382        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
383        characters when looking for a newline.
385     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
387     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
388        in debug output.
390     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
391        long printing in the pcrecpp unittest when running under MinGW.
393     6. ESC_K was left out of the EBCDIC table.
395     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
396        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
397        limit also applies to "virtual nesting" when a pattern is recursive, and in
398        this case 1000 isn't so big. I have been able to remove this limit at the
399        expense of backing off one optimization in certain circumstances. Normally,
400        when pcre_exec() would call its internal match() function recursively and
401        immediately return the result unconditionally, it uses a "tail recursion"
402        feature to save stack. However, when a subpattern that can match an empty
403        string has an unlimited repetition quantifier, it no longer makes this
404        optimization. That gives it a stack frame in which to save the data for
405        checking that an empty string has been matched. Previously this was taken
406        from the 1000-entry workspace that had been reserved. So now there is no
407        explicit limit, but more stack is used.
409     8. Applied Daniel's patches to solve problems with the import/export magic
410        syntax that is required for Windows, and which was going wrong for the
411        pcreposix and pcrecpp parts of the library. These were overlooked when this
412        problem was solved for the main library.
414     9. There were some crude static tests to avoid integer overflow when computing
415        the size of patterns that contain repeated groups with explicit upper
416        limits. As the maximum quantifier is 65535, the maximum group length was
417        set at 30,000 so that the product of these two numbers did not overflow a
418        32-bit integer. However, it turns out that people want to use groups that
419        are longer than 30,000 bytes (though not repeat them that many times).
420        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
421        made it possible to implement the integer overflow checks in a much more
422        dynamic way, which I have now done. The artificial limitation on group
423        length has been removed - we now have only the limit on the total length of
424        the compiled pattern, which depends on the LINK_SIZE setting.
426    10. Fixed a bug in the documentation for get/copy named substring when
427        duplicate names are permitted. If none of the named substrings are set, the
428        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
429        empty string.
431    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
432        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
433        because the ] is interpreted as the first data character and the
434        terminating ] is not found. PCRE has been made compatible with Perl in this
435        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
436        cause memory overwriting.
438    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
439        string has been matched (to stop an infinite loop). It was not recognizing
440        a conditional subpattern that could match an empty string if that
441        subpattern was within another subpattern. For example, it looped when
442        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
443        condition was not nested. This bug has been fixed.
445    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
446        past the start of the subject in the presence of bytes with the top bit
447        set, for example "\x8aBCD".
449    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
450        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
452    14. Optimized (?!) to (*FAIL).
454    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
455        This restricts code points to be within the range 0 to 0x10FFFF, excluding
456        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
457        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
458        does: it's just the validity check that is more restrictive.
460    16. Inserted checks for integer overflows during escape sequence (backslash)
461        processing, and also fixed erroneous offset values for syntax errors during
462        backslash processing.
464    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
465        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
467    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
468        caused an overrun.
470    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
471        something other than just ASCII characters) inside a group that had an
472        unlimited repeat caused a loop at compile time (while checking to see
473        whether the group could match an empty string).
475    20. Debugging a pattern containing \p or \P could cause a crash. For example,
476        [\P{Any}] did so. (Error in the code for printing property names.)
478    21. An orphan \E inside a character class could cause a crash.
480    22. A repeated capturing bracket such as (A)? could cause a wild memory
481        reference during compilation.
483    23. There are several functions in pcre_compile() that scan along a compiled
484        expression for various reasons (e.g. to see if it's fixed length for look
485        behind). There were bugs in these functions when a repeated \p or \P was
486        present in the pattern. These operators have additional parameters compared
487        with \d, etc, and these were not being taken into account when moving along
488        the compiled data. Specifically:
490        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
491            length.
493        (b) An item such as \pL+ within a repeated group could cause crashes or
494            loops.
496        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
497            "reference to non-existent subpattern" error.
499        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
501    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
502        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
504    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
506    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
507        character were causing crashes (broken optimization).
509    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
510        \p or \P) caused a compile-time loop.
512    28. More problems have arisen in unanchored patterns when CRLF is a valid line
513        break. For example, the unstudied pattern [\r\n]A does not match the string
514        "\r\nA" because change 7.0/46 below moves the current point on by two
515        characters after failing to match at the start. However, the pattern \nA
516        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
517        the same is true. There doesn't seem any very clean way out of this, but
518        what I have chosen to do makes the common cases work: PCRE now takes note
519        of whether there can be an explicit match for \r or \n anywhere in the
520        pattern, and if so, 7.0/46 no longer applies. As part of this change,
521        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
522        pattern has explicit CR or LF references.
524    29. Added (*CR) etc for changing newline setting at start of pattern.
527    Version 7.2 19-Jun-07
528    ---------------------
530     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
531        which is apparently normally available under Windows.
533     2. Re-jig the pcregrep tests with different newline settings in an attempt
534        to make them independent of the local environment's newline setting.
536     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
538     4. Some of the "internals" tests were previously cut out when the link size
539        was not 2, because the output contained actual offsets. The recent new
540        "Z" feature of pcretest means that these can be cut out, making the tests
541        usable with all link sizes.
543     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
544        stack recursion. This gives a massive performance boost under BSD, but just
545        a small improvement under Linux. However, it saves one field in the frame
546        in all cases.
548     6. Added more features from the forthcoming Perl 5.10:
550        (a) (?-n) (where n is a string of digits) is a relative subroutine or
551            recursion call. It refers to the nth most recently opened parentheses.
553        (b) (?+n) is also a relative subroutine call; it refers to the nth next
554            to be opened parentheses.
556        (c) Conditions that refer to capturing parentheses can be specified
557            relatively, for example, (?(-2)... or (?(+3)...
559        (d) \K resets the start of the current match so that everything before
560            is not part of it.
562        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
564        (f) \g{name} is another synonym - part of Perl 5.10's unification of
565            reference syntax.
567        (g) (?| introduces a group in which the numbering of parentheses in each
568            alternative starts with the same number.
570        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
572     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
575     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
576        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
577        for detecting groups that can match an empty string.
579     9. A pattern with a very large number of alternatives (more than several
580        hundred) was running out of internal workspace during the pre-compile
581        phase, where pcre_compile() figures out how much memory will be needed. A
582        bit of new cunning has reduced the workspace needed for groups with
583        alternatives. The 1000-alternative test pattern now uses 12 bytes of
584        workspace instead of running out of the 4096 that are available.
586    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
588    11. Applied patch from Google to remove an optimization that didn't quite work.
589        The report of the bug said:
591          pcrecpp::RE("a*").FullMatch("aaa") matches, while
592          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
593          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
595    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
596        it matched the wrong number of bytes.
599    Version 7.1 24-Apr-07
600    ---------------------
602     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
603        that is more "standard", making use of automake and other Autotools. There
604        is some re-arrangement of the files and adjustment of comments consequent
605        on this.
607     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
608        for recursive directory scanning broke on some systems because the files
609        are not scanned in any specific order and on different systems the order
610        was different. A call to "sort" has been inserted into RunGrepTest for the
611        approprate test as a short-term fix. In the longer term there may be an
612        alternative.
614     3. I had an email from Eric Raymond about problems translating some of PCRE's
615        man pages to HTML (despite the fact that I distribute HTML pages, some
616        people do their own conversions for various reasons). The problems
617        concerned the use of low-level troff macros .br and .in. I have therefore
618        removed all such uses from the man pages (some were redundant, some could
619        be replaced by .nf/.fi pairs). The 132html script that I use to generate
620        HTML has been updated to handle .nf/.fi and to complain if it encounters
621        .br or .in.
623     4. Updated comments in configure.ac that get placed in config.h.in and also
624        arranged for config.h to be included in the distribution, with the name
625        config.h.generic, for the benefit of those who have to compile without
626        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
628     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
629        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
630        makevp.bat for the current PCRE, using the additional files
631        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
633     6. A Windows user reported a minor discrepancy with test 2, which turned out
634        to be caused by a trailing space on an input line that had got lost in his
635        copy. The trailing space was an accident, so I've just removed it.
637     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
638        that is needed.
640     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
641        as "const" (a) because they are and (b) because it helps the PHP
642        maintainers who have recently made a script to detect big data structures
643        in the php code that should be moved to the .rodata section. I remembered
644        to update Builducptable as well, so it won't revert if ucptable.h is ever
645        re-created.
647     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
648        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
649        order to be able to cut out the UTF-8 tables in the latter when UTF-8
650        support is not required. This saves 1.5-2K of code, which is important in
651        some applications.
653        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
654        so as not to refer to the tables, even though these functions will never be
655        called when UTF-8 support is disabled. Otherwise there are problems with a
656        shared library.
658    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
660        (a) It was defining its arguments as char * instead of void *.
662        (b) It was assuming that all moves were upwards in memory; this was true
663            a long time ago when I wrote it, but is no longer the case.
665        The emulated memove() is provided for those environments that have neither
666        memmove() nor bcopy(). I didn't think anyone used it these days, but that
667        is clearly not the case, as these two bugs were recently reported.
669    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
670        and Detrail to create the HTML documentation, the .txt form of the man
671        pages, and it removes trailing spaces from listed files. It also creates
672        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
673        case, it wraps all the #defines with #ifndefs. This script should be run
674        before "make dist".
676    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
677        with Unicode property support.
679        (a) For a maximizing quantifier, if the two different cases of the
680            character were of different lengths in their UTF-8 codings (there are
681            some cases like this - I found 11), and the matching function had to
682            back up over a mixture of the two cases, it incorrectly assumed they
683            were both the same length.
685        (b) When PCRE was configured to use the heap rather than the stack for
686            recursion during matching, it was not correctly preserving the data for
687            the other case of a UTF-8 character when checking ahead for a match
688            while processing a minimizing repeat. If the check also involved
689            matching a wide character, but failed, corruption could cause an
690            erroneous result when trying to check for a repeat of the original
691            character.
693    13. Some tidying changes to the testing mechanism:
695        (a) The RunTest script now detects the internal link size and whether there
696            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
697            values substituted by "configure". (The RunGrepTest script already did
698            this for UTF-8.) The configure.ac script no longer substitutes the
699            relevant variables.
701        (b) The debugging options /B and /D in pcretest show the compiled bytecode
702            with length and offset values. This means that the output is different
703            for different internal link sizes. Test 2 is skipped for link sizes
704            other than 2 because of this, bypassing the problem. Unfortunately,
705            there was also a test in test 3 (the locale tests) that used /B and
706            failed for link sizes other than 2. Rather than cut the whole test out,
707            I have added a new /Z option to pcretest that replaces the length and
708            offset values with spaces. This is now used to make test 3 independent
709            of link size. (Test 2 will be tidied up later.)
711    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
712        segmentation fault instead of returning the appropriate error message.
714    15. In multiline mode when the newline sequence was set to "any", the pattern
715        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
716        This doesn't seem right; it now treats the CRLF combination as the line
717        ending, and so does not match in that case. It's only a pattern such as ^$
718        that would hit this one: something like ^ABC$ would have failed after \r
719        and then tried again after \r\n.
721    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
722        in an attempt to make files that differ only in their line terminators
723        compare equal. This works on Linux.
725    17. Under certain error circumstances pcregrep might try to free random memory
726        as it exited. This is now fixed, thanks to valgrind.
728    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
729        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
730        was because its rules for how to advance for /g after matching an empty
731        string at the end of a line did not allow for this case. They now check for
732        it specially.
734    20. pcretest is supposed to handle patterns and data of any length, by
735        extending its buffers when necessary. It was getting this wrong when the
736        buffer for a data line had to be extended.
738    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
739        CRLF as a newline sequence.
741    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
742        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
743        I have nevertheless tidied it up.
745    23. Added some casts to kill warnings from HP-UX ia64 compiler.
747    24. Added a man page for pcre-config.
750    Version 7.0 19-Dec-06
751    ---------------------
753     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
754        moving to gcc 4.1.1.
756     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
757        sys/time.h, which is documented as needed for this function. It doesn't
758        seem to matter on Linux, but it showed up on some releases of OS X.
760     3. It seems that there are systems where bytes whose values are greater than
761        127 match isprint() in the "C" locale. The "C" locale should be the
762        default when a C program starts up. In most systems, only ASCII printing
763        characters match isprint(). This difference caused the output from pcretest
764        to vary, making some of the tests fail. I have changed pcretest so that:
766        (a) When it is outputting text in the compiled version of a pattern, bytes
767            other than 32-126 are always shown as hex escapes.
769        (b) When it is outputting text that is a matched part of a subject string,
770            it does the same, unless a different locale has been set for the match
771            (using the /L modifier). In this case, it uses isprint() to decide.
773     4. Fixed a major bug that caused incorrect computation of the amount of memory
774        required for a compiled pattern when options that changed within the
775        pattern affected the logic of the preliminary scan that determines the
776        length. The relevant options are -x, and -i in UTF-8 mode. The result was
777        that the computed length was too small. The symptoms of this bug were
778        either the PCRE error "internal error: code overflow" from pcre_compile(),
779        or a glibc crash with a message such as "pcretest: free(): invalid next
780        size (fast)". Examples of patterns that provoked this bug (shown in
781        pcretest format) are:
783          /(?-x: )/x
784          /(?x)(?-x: \s*#\s*)/
785          /((?i)[\x{c0}])/8
786          /(?i:[\x{c0}])/8
788        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
789        is now done differently.
791     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
792        wrapper classes; (b) implement a new function in the C++ scanner that is
793        more efficient than the old way of doing things because it avoids levels of
794        recursion in the regex matching; (c) add a paragraph to the documentation
795        for the FullMatch() function.
797     6. The escape sequence \n was being treated as whatever was defined as
798        "newline". Not only was this contrary to the documentation, which states
799        that \n is character 10 (hex 0A), but it also went horribly wrong when
800        "newline" was defined as CRLF. This has been fixed.
802     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
803        was being set to -1 for the "end of line" case (supposedly a value that no
804        character can have). Though this value is never used (the check for end of
805        line is "zero bytes in current character"), it caused compiler complaints.
806        I've changed it to 0xffffffff.
808     8. In pcre_version.c, the version string was being built by a sequence of
809        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
810        string (as it is for production releases) called a macro with an empty
811        argument. The C standard says the result of this is undefined. The gcc
812        compiler treats it as an empty string (which was what was wanted) but it is
813        reported that Visual C gives an error. The source has been hacked around to
814        avoid this problem.
816     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
817        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
818        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
819        of them did).
821    10. Originally, pcretest opened its input and output without "b"; then I was
822        told that "b" was needed in some environments, so it was added for release
823        5.0 to both the input and output. (It makes no difference on Unix-like
824        systems.) Later I was told that it is wrong for the input on Windows. I've
825        now abstracted the modes into two macros, to make it easier to fiddle with
826        them, and removed "b" from the input mode under Windows.
828    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
830    12. Added -help and --help to pcretest as an official way of being reminded
831        of the options.
833    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
834        and pcrecpp.cc because they annoy compilers at high warning levels.
836    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
838    15. Fixed an occurrence of == in configure.ac that should have been = (shell
839        scripts are not C programs :-) and which was not noticed because it works
840        on Linux.
842    16. pcretest is supposed to handle any length of pattern and data line (as one
843        line or as a continued sequence of lines) by extending its input buffer if
844        necessary. This feature was broken for very long pattern lines, leading to
845        a string of junk being passed to pcre_compile() if the pattern was longer
846        than about 50K.
848    17. I have done a major re-factoring of the way pcre_compile() computes the
849        amount of memory needed for a compiled pattern. Previously, there was code
850        that made a preliminary scan of the pattern in order to do this. That was
851        OK when PCRE was new, but as the facilities have expanded, it has become
852        harder and harder to keep it in step with the real compile phase, and there
853        have been a number of bugs (see for example, 4 above). I have now found a
854        cunning way of running the real compile function in a "fake" mode that
855        enables it to compute how much memory it would need, while actually only
856        ever using a few hundred bytes of working memory and without too many
857        tests of the mode. This should make future maintenance and development
858        easier. A side effect of this work is that the limit of 200 on the nesting
859        depth of parentheses has been removed (though this was never a serious
860        limitation, I suspect). However, there is a downside: pcre_compile() now
861        runs more slowly than before (30% or more, depending on the pattern). I
862        hope this isn't a big issue. There is no effect on runtime performance.
864    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
865        newline (only possible for the last line of a file) and it was a
866        pattern that set a locale (followed by /Lsomething), pcretest crashed.
868    19. Added additional timing features to pcretest. (1) The -tm option now times
869        matching only, not compiling. (2) Both -t and -tm can be followed, as a
870        separate command line item, by a number that specifies the number of
871        repeats to use when timing. The default is 50000; this gives better
872        precision, but takes uncomfortably long for very large patterns.
874    20. Extended pcre_study() to be more clever in cases where a branch of a
875        subpattern has no definite first character. For example, (a*|b*)[cd] would
876        previously give no result from pcre_study(). Now it recognizes that the
877        first character must be a, b, c, or d.
879    21. There was an incorrect error "recursive call could loop indefinitely" if
880        a subpattern (or the entire pattern) that was being tested for matching an
881        empty string contained only one non-empty item after a nested subpattern.
882        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
883        incorrectly, because the \d was being skipped in the check.
885    22. The pcretest program now has a new pattern option /B and a command line
886        option -b, which is equivalent to adding /B to every pattern. This causes
887        it to show the compiled bytecode, without the additional information that
888        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
889        is the same as /B/I).
891    23. A new optimization is now able automatically to treat some sequences such
892        as a*b as a*+b. More specifically, if something simple (such as a character
893        or a simple class like \d) has an unlimited quantifier, and is followed by
894        something that cannot possibly match the quantified thing, the quantifier
895        is automatically "possessified".
897    24. A recursive reference to a subpattern whose number was greater than 39
898        went wrong under certain circumstances in UTF-8 mode. This bug could also
899        have affected the operation of pcre_study().
901    25. Realized that a little bit of performance could be had by replacing
902        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
904    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
906    27. Possessive quantifiers such as a++ were previously implemented by turning
907        them into atomic groups such as ($>a+). Now they have their own opcodes,
908        which improves performance. This includes the automatically created ones
909        from 23 above.
911    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
912        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
913        the first matched character to be a colon. This applied both to named and
914        numbered groups.
916    29. The ucpinternal.h header file was missing its idempotency #ifdef.
918    30. I was sent a "project" file called libpcre.a.dev which I understand makes
919        building PCRE on Windows easier, so I have included it in the distribution.
921    31. There is now a check in pcretest against a ridiculously large number being
922        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
923        loop, the loop is abandoned.
925    32. Forward references to subpatterns in conditions such as (?(2)...) where
926        subpattern 2 is defined later cause pcre_compile() to search forwards in
927        the pattern for the relevant set of parentheses. This search went wrong
928        when there were unescaped parentheses in a character class, parentheses
929        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
931    33. "Subroutine" calls and backreferences were previously restricted to
932        referencing subpatterns earlier in the regex. This restriction has now
933        been removed.
935    34. Added a number of extra features that are going to be in Perl 5.10. On the
936        whole, these are just syntactic alternatives for features that PCRE had
937        previously implemented using the Python syntax or my own invention. The
938        other formats are all retained for compatibility.
940        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
941            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
942            also .NET compatible.
944        (b) A recursion or subroutine call to a named group can now be defined as
945            (?&name) as well as (?P>name).
947        (c) A backreference to a named group can now be defined as \k<name> or
948            \k'name' as well as (?P=name). The new forms, as well as being in Perl
949            5.10, are also .NET compatible.
951        (d) A conditional reference to a named group can now use the syntax
952            (?(<name>) or (?('name') as well as (?(name).
954        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
955            groups (named and numbered) that are never evaluated inline, but can be
956            called as "subroutines" from elsewhere. In effect, the DEFINE condition
957            is always false. There may be only one alternative in such a group.
959        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
960            as the simple (?(R). The condition is true only if the most recent
961            recursion is that of the given number or name. It does not search out
962            through the entire recursion stack.
964        (g) The escape \gN or \g{N} has been added, where N is a positive or
965            negative number, specifying an absolute or relative reference.
967    35. Tidied to get rid of some further signed/unsigned compiler warnings and
968        some "unreachable code" warnings.
970    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
971        things, this adds five new scripts.
973    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
974        There were also incompatibilities regarding the handling of \Q..\E inside
975        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
976        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
978    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
979        matches an empty string, and forcibly breaks the loop. There were bugs in
980        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
981        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
982        separate and independent bugs (that affected different cases) have been
983        fixed.
985    39. Refactored the code to abolish the use of different opcodes for small
986        capturing bracket numbers. This is a tidy that I avoided doing when I
987        removed the limit on the number of capturing brackets for 3.5 back in 2001.
988        The new approach is not only tidier, it makes it possible to reduce the
989        memory needed to fix the previous bug (38).
991    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
992        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
993        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
994        mode.
996    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
997        report.
999    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1000        copy construction and assignment in the C++ wrapper.
1002    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1003        couple of bugs that could have given wrong results in the "--newline=crlf"
1004        case.
1006    44. Added a number of casts and did some reorganization of signed/unsigned int
1007        variables following suggestions from Dair Grant. Also renamed the variable
1008        "this" as "item" because it is a C++ keyword.
1010    45. Arranged for dftables to add
1012          #include "pcre_internal.h"
1014        to pcre_chartables.c because without it, gcc 4.x may remove the array
1015        definition from the final binary if PCRE is built into a static library and
1016        dead code stripping is activated.
1018    46. For an unanchored pattern, if a match attempt fails at the start of a
1019        newline sequence, and the newline setting is CRLF or ANY, and the next two
1020        characters are CRLF, advance by two characters instead of one.
1023    Version 6.7 04-Jul-06
1024    ---------------------
1026     1. In order to handle tests when input lines are enormously long, pcretest has
1027        been re-factored so that it automatically extends its buffers when
1028        necessary. The code is crude, but this _is_ just a test program. The
1029        default size has been increased from 32K to 50K.
1031     2. The code in pcre_study() was using the value of the re argument before
1032        testing it for NULL. (Of course, in any sensible call of the function, it
1033        won't be NULL.)
1035     3. The memmove() emulation function in pcre_internal.h, which is used on
1036        systems that lack both memmove() and bcopy() - that is, hardly ever -
1037        was missing a "static" storage class specifier.
1039     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1040        containing an extended class (one that cannot be represented by a bitmap
1041        because it contains high-valued characters or Unicode property items, e.g.
1042        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1043        pattern, but PCRE should not loop if you do not (it no longer does).
1044        [Detail: two cases were found: (a) a repeated subpattern containing an
1045        extended class; (b) a recursive reference to a subpattern that followed a
1046        previous extended class. It wasn't skipping over the extended class
1047        correctly when UTF-8 mode was not set.]
1049     5. A negated single-character class was not being recognized as fixed-length
1050        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1051        compile error "lookbehind assertion is not fixed length".
1053     6. The RunPerlTest auxiliary script was showing an unexpected difference
1054        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1055        write a Perl script that can interpret lines of an input file either as
1056        byte characters or as UTF-8, which is what "perltest" was being required to
1057        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1058        can't do is switch easily at run time between having the "use utf8;" pragma
1059        or not. In the end, I fudged it by using the RunPerlTest script to insert
1060        "use utf8;" explicitly for the UTF-8 tests.
1062     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1063        the end of the subject string, contrary to the documentation and to what
1064        Perl does. This was true of both matching functions. Now it matches only at
1065        the start of the subject and immediately after *internal* newlines.
1067     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1068        a pointer to an int instead of a pointer to an unsigned long int. This
1069        caused problems on 64-bit systems.
1071     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1072        instance of the 'standard' template library not being so standard".
1074    10. There was no check on the number of named subpatterns nor the maximum
1075        length of a subpattern name. The product of these values is used to compute
1076        the size of the memory block for a compiled pattern. By supplying a very
1077        long subpattern name and a large number of named subpatterns, the size
1078        computation could be caused to overflow. This is now prevented by limiting
1079        the length of names to 32 characters, and the number of named subpatterns
1080        to 10,000.
1082    11. Subpatterns that are repeated with specific counts have to be replicated in
1083        the compiled pattern. The size of memory for this was computed from the
1084        length of the subpattern and the repeat count. The latter is limited to
1085        65535, but there was no limit on the former, meaning that integer overflow
1086        could in principle occur. The compiled length of a repeated subpattern is
1087        now limited to 30,000 bytes in order to prevent this.
1089    12. Added the optional facility to have named substrings with the same name.
1091    13. Added the ability to use a named substring as a condition, using the
1092        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1093        are numbers (not recommended). Forward references are permitted.
1095    14. Added forward references in named backreferences (if you see what I mean).
1097    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1098        pattern could run off the end of the subject. For example, the pattern
1099        "(?s)(.{1,5})"8 did this with the subject "ab".
1101    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1102        PCRE_CASELESS was set when matching characters that were quantified with ?
1103        or *.
1105    17. A character class other than a single negated character that had a minimum
1106        but no maximum quantifier - for example [ab]{6,} - was not handled
1107        correctly by pce_dfa_exec(). It would match only one character.
1109    18. A valid (though odd) pattern that looked like a POSIX character
1110        class but used an invalid character after [ (for example [[,abc,]]) caused
1111        pcre_compile() to give the error "Failed: internal error: code overflow" or
1112        in some cases to crash with a glibc free() error. This could even happen if
1113        the pattern terminated after [[ but there just happened to be a sequence of
1114        letters, a binary zero, and a closing ] in the memory that followed.
1116    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1117        over the years. Originally (before any Unicode support), just the bottom 8
1118        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1119        output from "man perlunicode" includes this:
1121          The regular expression compiler produces polymorphic opcodes.  That
1122          is, the pattern adapts to the data and automatically switches to
1123          the Unicode character scheme when presented with Unicode data--or
1124          instead uses a traditional byte scheme when presented with byte
1125          data.
1127        Sadly, a wide octal escape does not cause a switch, and in a string with
1128        no other multibyte characters, these octal escapes are treated as before.
1129        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1130        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1131        Unicode string.
1133        I have not perpetrated such confusion in PCRE. Up till now, it took just
1134        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1135        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1136        translate to the appropriate multibyte character.
1138    29. Applied some refactoring to reduce the number of warnings from Microsoft
1139        and Borland compilers. This has included removing the fudge introduced
1140        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1141        a warning about an unused variable.
1143    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1144        characters since release 4.0, because Perl (from release 5.004) does not.
1145        [Or at least, is documented not to: some releases seem to be in conflict
1146        with the documentation.] However, when a pattern was studied with
1147        pcre_study() and all its branches started with \s, PCRE still included VT
1148        as a possible starting character. Of course, this did no harm; it just
1149        caused an unnecessary match attempt.
1151    22. Removed a now-redundant internal flag bit that recorded the fact that case
1152        dependency changed within the pattern. This was once needed for "required
1153        byte" processing, but is no longer used. This recovers a now-scarce options
1154        bit. Also moved the least significant internal flag bit to the most-
1155        significant bit of the word, which was not previously used (hangover from
1156        the days when it was an int rather than a uint) to free up another bit for
1157        the future.
1159    23. Added support for CRLF line endings as well as CR and LF. As well as the
1160        default being selectable at build time, it can now be changed at runtime
1161        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1162        specify that it is scanning data with non-default line endings.
1164    24. Changed the definition of CXXLINK to make it agree with the definition of
1165        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1167    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1168        recursions. This makes a big different to stack usage for some patterns.
1170    26. If a subpattern containing a named recursion or subroutine reference such
1171        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1172        the space required for the compiled pattern went wrong and gave too small a
1173        value. Depending on the environment, this could lead to "Failed: internal
1174        error: code overflow at offset 49" or "glibc detected double free or
1175        corruption" errors.
1177    27. Applied patches from Google (a) to support the new newline modes and (b) to
1178        advance over multibyte UTF-8 characters in GlobalReplace.
1180    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1181        difference for some implementation of PCRE in some Windows version.
1183    29. Added some extra testing facilities to pcretest:
1185        \q<number>   in a data line sets the "match limit" value
1186        \Q<number>   in a data line sets the "match recursion limt" value
1187        -S <number>  sets the stack size, where <number> is in megabytes
1189        The -S option isn't available for Windows.
1192    Version 6.6 06-Feb-06
1193    ---------------------
1195     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1196        in pcreposix.h. I have copied the definition from pcre.h.
1198     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1199        because pcre.h is no longer a built file.
1201     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1202        not normally included in the compiled code.
1205  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
1206  ---------------------  ---------------------

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