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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.0 02 Jul-08
5    ---------------------
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
17    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18        a group with a zero qualifier. The result of the study could be incorrect,
19        or the function might crash, depending on the pattern.
21    4.  Caseless matching was not working for non-ASCII characters in back
22        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23        It now works when Unicode Property Support is available.
25    5.  In pcretest, an escape such as \x{de} in the data was always generating
26        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
27        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
28        truncation.
30    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
32    7.  Added two (int) casts to pcregrep when printing the difference of two
33        pointers, in case they are 64-bit values.
35    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
36        test 2 if it fails.
38    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
39        and a #define of that name to empty if it is not externally set. This is to
40        allow users of MSVC to set it if necessary.
42    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
43        the convenience functions in the pcre_get.c source file.
46    Version 7.7 07-May-08
47    ---------------------
49    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
50        a string to a long long, pretend we don't even have a long long." This is
51        done by checking for the strtoq, strtoll, and _strtoi64 functions.
53    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
54        pre-7.6 versions, which defined a global no_arg variable instead of putting
55        it in the RE class. (See also #8 below.)
57    3.  Remove a line of dead code, identified by coverity and reported by Nuno
58        Lopes.
60    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
62        (1) The include/exclude patterns were being applied to the whole pathnames
63            of files, instead of just to the final components.
65        (2) If there was more than one level of directory, the subdirectories were
66            skipped unless they satisfied the include/exclude conditions. This is
67            inconsistent with GNU grep (and could even be seen as contrary to the
68            pcregrep specification - which I improved to make it absolutely clear).
69            The action now is always to scan all levels of directory, and just
70            apply the include/exclude patterns to regular files.
72    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
73        --exclude_dir in the tests to avoid scanning .svn directories.
75    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
76        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
77        doesn't support NULs in patterns.
79    7.  Added some missing "const"s to declarations of static tables in
80        pcre_compile.c and pcre_dfa_exec.c.
82    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
83        caused by fix #2  above. (Subsequently also a second patch to fix the
84        first patch. And a third patch - this was a messy problem.)
86    9.  Applied Craig's patch to remove the use of push_back().
88    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
89        matching function regexec().
91    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
92        which, however, unlike Perl's \g{...}, are subroutine calls, not back
93        references. PCRE supports relative numbers with this syntax (I don't think
94        Oniguruma does).
96    12. Previously, a group with a zero repeat such as (...){0} was completely
97        omitted from the compiled regex. However, this means that if the group
98        was called as a subroutine from elsewhere in the pattern, things went wrong
99        (an internal error was given). Such groups are now left in the compiled
100        pattern, with a new opcode that causes them to be skipped at execution
101        time.
103    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
104        to the way PCRE behaves:
106        (a) A lone ] character is dis-allowed (Perl treats it as data).
108        (b) A back reference to an unmatched subpattern matches an empty string
109            (Perl fails the current match path).
111        (c) A data ] in a character class must be notated as \] because if the
112            first data character in a class is ], it defines an empty class. (In
113            Perl it is not possible to have an empty class.) The empty class []
114            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
115            The negative empty class [^] matches any one character, independently
116            of the DOTALL setting.
118    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
119        non-existent subpattern following a character class starting with ']' and
120        containing () gave an internal compiling error instead of "reference to
121        non-existent subpattern". Fortunately, when the pattern did exist, the
122        compiled code was correct. (When scanning forwards to check for the
123        existencd of the subpattern, it was treating the data ']' as terminating
124        the class, so got the count wrong. When actually compiling, the reference
125        was subsequently set up correctly.)
127    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
128        it was being rejected as not supported by pcre_dfa_exec(), even though
129        other assertions are supported. I have made pcre_dfa_exec() support
130        (*FAIL).
132    16. The implementation of 13c above involved the invention of a new opcode,
133        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
134        cannot be changed at match time, I realized I could make a small
135        improvement to matching performance by compiling OP_ALLANY instead of
136        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
137        on the OP_ANY path.
139    17. Compiling pcretest on Windows with readline support failed without the
140        following two fixes: (1) Make the unistd.h include conditional on
141        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
143    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
144        ncurses library to be included for pcretest when ReadLine support is
145        requested, but also to allow for it to be overridden. This patch came from
146        Daniel Bergström.
148    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
149        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
150        any errors with the current Unicode tables. Thanks to Peter Kankowski for
151        spotting this.
154    Version 7.6 28-Jan-08
155    ---------------------
157    1.  A character class containing a very large number of characters with
158        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
159        overflow.
161    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
162        HAVE_LONG_LONG is not defined.
164    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
165        bring them up to date and include new features. This patch includes:
167        - Fixed PH's badly added libz and libbz2 support.
168        - Fixed a problem with static linking.
169        - Added pcredemo. [But later removed - see 7 below.]
170        - Fixed dftables problem and added an option.
171        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
172            HAVE_LONG_LONG.
173        - Added readline support for pcretest.
174        - Added an listing of the option settings after cmake has run.
176    4.  A user submitted a patch to Makefile that makes it easy to create
177        "pcre.dll" under mingw when using Configure/Make. I added stuff to
178        Makefile.am that cause it to include this special target, without
179        affecting anything else. Note that the same mingw target plus all
180        the other distribution libraries and programs are now supported
181        when configuring with CMake (see 6 below) instead of with
182        Configure/Make.
184    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
185        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
186        exported in the Windows port". It has not yet been confirmed that the patch
187        solves the problem, but it does no harm.
189    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
190        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
191        with CMake, and also correct the comment about stack recursion.
193    7.  Remove the automatic building of pcredemo from the ./configure system and
194        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
195        of a program that users should build themselves after PCRE is installed, so
196        building it automatically is not really right. What is more, it gave
197        trouble in some build environments.
199    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
202    Version 7.5 10-Jan-08
203    ---------------------
205    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
206        values in parens when parsing an RE using the C++ wrapper."
208    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
209        Characters greater than 255 were excluded from the class instead of being
210        included.
212    3.  The same bug as (2) above applied to negated POSIX classes such as
213        [:^space:].
215    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
216        defined or documented. It seems to have been a typo for PCRE_STATIC, so
217        I have changed it.
219    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
220        first named subpattern) and a construct such as (?&a) would reference the
221        first named subpattern whose name started with "a" (in other words, the
222        length check was missing). Both these problems are fixed. "Subpattern name
223        expected" is now given for (?&) (a zero-length name), and this patch also
224        makes it give the same error for \k'' (previously it complained that that
225        was a reference to a non-existent subpattern).
227    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
228        this is right because (?- can be followed by option settings as well as by
229        digits. I have, however, made the messages clearer.
231    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
232        than the number used in the conditional) now cause a compile-time error.
233        This is actually not compatible with Perl, which accepts such patterns, but
234        treats the conditional as always being FALSE (as PCRE used to), but it
235        seems to me that giving a diagnostic is better.
237    8.  Change "alphameric" to the more common word "alphanumeric" in comments
238        and messages.
240    9.  Fix two occurrences of "backslash" in comments that should have been
241        "backspace".
243    10. Remove two redundant lines of code that can never be obeyed (their function
244        was moved elsewhere).
246    11. The program that makes PCRE's Unicode character property table had a bug
247        which caused it to generate incorrect table entries for sequences of
248        characters that have the same character type, but are in different scripts.
249        It amalgamated them into a single range, with the script of the first of
250        them. In other words, some characters were in the wrong script. There were
251        thirteen such cases, affecting characters in the following ranges:
253          U+002b0 - U+002c1
254          U+0060c - U+0060d
255          U+0061e - U+00612
256          U+0064b - U+0065e
257          U+0074d - U+0076d
258          U+01800 - U+01805
259          U+01d00 - U+01d77
260          U+01d9b - U+01dbf
261          U+0200b - U+0200f
262          U+030fc - U+030fe
263          U+03260 - U+0327f
264          U+0fb46 - U+0fbb1
265          U+10450 - U+1049d
267    12. The -o option (show only the matching part of a line) for pcregrep was not
268        compatible with GNU grep in that, if there was more than one match in a
269        line, it showed only the first of them. It now behaves in the same way as
270        GNU grep.
272    13. If the -o and -v options were combined for pcregrep, it printed a blank
273        line for every non-matching line. GNU grep prints nothing, and pcregrep now
274        does the same. The return code can be used to tell if there were any
275        non-matching lines.
277    14. Added --file-offsets and --line-offsets to pcregrep.
279    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
280        infinitely looping recursion. The bug was that positive lookaheads were not
281        being skipped when checking for a possible empty match (negative lookaheads
282        and both kinds of lookbehind were skipped).
284    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
285        inclusion of <windows.h> to before rather than after the definition of
286        INVALID_FILE_ATTRIBUTES (patch from David Byron).
288    17. Specifying a possessive quantifier with a specific limit for a Unicode
289        character property caused pcre_compile() to compile bad code, which led at
290        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
291        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
292        caused the error; without that there was no problem.
294    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
296    19. Added --enable-pcretest-libreadline.
298    20. In pcrecpp.cc, the variable 'count' was incremented twice in
299        RE::GlobalReplace(). As a result, the number of replacements returned was
300        double what it should be. I removed one of the increments, but Craig sent a
301        later patch that removed the other one (the right fix) and added unit tests
302        that check the return values (which was not done before).
304    21. Several CMake things:
306        (1) Arranged that, when cmake is used on Unix, the libraries end up with
307            the names libpcre and libpcreposix, not just pcre and pcreposix.
309        (2) The above change means that pcretest and pcregrep are now correctly
310            linked with the newly-built libraries, not previously installed ones.
314    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
315        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
316        UTF-8 newline character). The key issue is that the pattern starts .*;
317        this means that the match must be either at the beginning, or after a
318        newline. The bug was in the code for advancing after a failed match and
319        checking that the new position followed a newline. It was not taking
320        account of UTF-8 characters correctly.
322    23. PCRE was behaving differently from Perl in the way it recognized POSIX
323        character classes. PCRE was not treating the sequence [:...:] as a
324        character class unless the ... were all letters. Perl, however, seems to
325        allow any characters between [: and :], though of course it rejects as
326        unknown any "names" that contain non-letters, because all the known class
327        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
328        for example, whereas PCRE did not - it did not recognize a POSIX character
329        class. This seemed a bit dangerous, so the code has been changed to be
330        closer to Perl. The behaviour is not identical to Perl, because PCRE will
331        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
332        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
333        Perl does, and where it didn't before.
335    24. Rewrite so as to remove the single use of %n from pcregrep because in some
336        Windows environments %n is disabled by default.
339    Version 7.4 21-Sep-07
340    ---------------------
342    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
343        means that a class such as [\s] counted as "explicit reference to CR or
344        LF". That isn't really right - the whole point of the change was to try to
345        help when there was an actual mention of one of the two characters. So now
346        the change happens only if \r or \n (or a literal CR or LF) character is
347        encountered.
349    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
350        of both had grown to the point where there were only 3 bits left.
351        Fortunately, there was spare space in the data structure, and so I have
352        moved the internal flags into a new 16-bit field to free up more option
353        bits.
355    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
356        but did not set the internal JCHANGED flag - either of these is enough to
357        control the way the "get" function works - but the PCRE_INFO_JCHANGED
358        facility is supposed to tell if (?J) was ever used, so now (?J) at the
359        start sets both bits.
361    4.  Added options (at build time, compile time, exec time) to change \R from
362        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
364    5.  doc/pcresyntax.html was missing from the distribution.
366    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
367        compatibility, even though it is no longer used.
369    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
370        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
371        windows.h file is present (where different names are used). [This was
372        reversed later after testing - see 16 below.]
374    8.  Changed all #include <config.h> to #include "config.h". There were also
375        some further <pcre.h> cases that I changed to "pcre.h".
377    9.  When pcregrep was used with the --colour option, it missed the line ending
378        sequence off the lines that it output.
380    10. It was pointed out to me that arrays of string pointers cause lots of
381        relocations when a shared library is dynamically loaded. A technique of
382        using a single long string with a table of offsets can drastically reduce
383        these. I have refactored PCRE in four places to do this. The result is
384        dramatic:
386          Originally:                          290
387          After changing UCP table:            187
388          After changing error message table:   43
389          After changing table of "verbs"       36
390          After changing table of Posix names   22
392        Thanks to the folks working on Gregex for glib for this insight.
394    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
395        unicode-properties was also set.
397    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
399    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
400        checked only for CRLF.
402    14. Added casts to pcretest.c to avoid compiler warnings.
404    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
406    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
407        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
408        entirely. This removes changes made in 7 above.
410    17. The CMake files have been updated, and there is now more information about
411        building with CMake in the NON-UNIX-USE document.
414    Version 7.3 28-Aug-07
415    ---------------------
417     1. In the rejigging of the build system that eventually resulted in 7.1, the
418        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
419        brackets there is not right, since it causes compilers to look for an
420        installed pcre.h, not the version that is in the source that is being
421        compiled (which of course may be different). I have changed it back to:
423          #include "pcre.h"
425        I have a vague recollection that the change was concerned with compiling in
426        different directories, but in the new build system, that is taken care of
427        by the VPATH setting the Makefile.
429     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
430        when the subject happened to end in the byte 0x85 (e.g. if the last
431        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
432        characters but of course it shouldn't be taken as a newline when it is part
433        of another character. The bug was that, for an unlimited repeat of . in
434        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
435        characters when looking for a newline.
437     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
439     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
440        in debug output.
442     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
443        long printing in the pcrecpp unittest when running under MinGW.
445     6. ESC_K was left out of the EBCDIC table.
447     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
448        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
449        limit also applies to "virtual nesting" when a pattern is recursive, and in
450        this case 1000 isn't so big. I have been able to remove this limit at the
451        expense of backing off one optimization in certain circumstances. Normally,
452        when pcre_exec() would call its internal match() function recursively and
453        immediately return the result unconditionally, it uses a "tail recursion"
454        feature to save stack. However, when a subpattern that can match an empty
455        string has an unlimited repetition quantifier, it no longer makes this
456        optimization. That gives it a stack frame in which to save the data for
457        checking that an empty string has been matched. Previously this was taken
458        from the 1000-entry workspace that had been reserved. So now there is no
459        explicit limit, but more stack is used.
461     8. Applied Daniel's patches to solve problems with the import/export magic
462        syntax that is required for Windows, and which was going wrong for the
463        pcreposix and pcrecpp parts of the library. These were overlooked when this
464        problem was solved for the main library.
466     9. There were some crude static tests to avoid integer overflow when computing
467        the size of patterns that contain repeated groups with explicit upper
468        limits. As the maximum quantifier is 65535, the maximum group length was
469        set at 30,000 so that the product of these two numbers did not overflow a
470        32-bit integer. However, it turns out that people want to use groups that
471        are longer than 30,000 bytes (though not repeat them that many times).
472        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
473        made it possible to implement the integer overflow checks in a much more
474        dynamic way, which I have now done. The artificial limitation on group
475        length has been removed - we now have only the limit on the total length of
476        the compiled pattern, which depends on the LINK_SIZE setting.
478    10. Fixed a bug in the documentation for get/copy named substring when
479        duplicate names are permitted. If none of the named substrings are set, the
480        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
481        empty string.
483    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
484        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
485        because the ] is interpreted as the first data character and the
486        terminating ] is not found. PCRE has been made compatible with Perl in this
487        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
488        cause memory overwriting.
490    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
491        string has been matched (to stop an infinite loop). It was not recognizing
492        a conditional subpattern that could match an empty string if that
493        subpattern was within another subpattern. For example, it looped when
494        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
495        condition was not nested. This bug has been fixed.
497    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
498        past the start of the subject in the presence of bytes with the top bit
499        set, for example "\x8aBCD".
501    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
502        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
504    14. Optimized (?!) to (*FAIL).
506    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
507        This restricts code points to be within the range 0 to 0x10FFFF, excluding
508        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
509        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
510        does: it's just the validity check that is more restrictive.
512    16. Inserted checks for integer overflows during escape sequence (backslash)
513        processing, and also fixed erroneous offset values for syntax errors during
514        backslash processing.
516    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
517        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
519    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
520        caused an overrun.
522    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
523        something other than just ASCII characters) inside a group that had an
524        unlimited repeat caused a loop at compile time (while checking to see
525        whether the group could match an empty string).
527    20. Debugging a pattern containing \p or \P could cause a crash. For example,
528        [\P{Any}] did so. (Error in the code for printing property names.)
530    21. An orphan \E inside a character class could cause a crash.
532    22. A repeated capturing bracket such as (A)? could cause a wild memory
533        reference during compilation.
535    23. There are several functions in pcre_compile() that scan along a compiled
536        expression for various reasons (e.g. to see if it's fixed length for look
537        behind). There were bugs in these functions when a repeated \p or \P was
538        present in the pattern. These operators have additional parameters compared
539        with \d, etc, and these were not being taken into account when moving along
540        the compiled data. Specifically:
542        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
543            length.
545        (b) An item such as \pL+ within a repeated group could cause crashes or
546            loops.
548        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
549            "reference to non-existent subpattern" error.
551        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
553    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
554        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
556    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
558    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
559        character were causing crashes (broken optimization).
561    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
562        \p or \P) caused a compile-time loop.
564    28. More problems have arisen in unanchored patterns when CRLF is a valid line
565        break. For example, the unstudied pattern [\r\n]A does not match the string
566        "\r\nA" because change 7.0/46 below moves the current point on by two
567        characters after failing to match at the start. However, the pattern \nA
568        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
569        the same is true. There doesn't seem any very clean way out of this, but
570        what I have chosen to do makes the common cases work: PCRE now takes note
571        of whether there can be an explicit match for \r or \n anywhere in the
572        pattern, and if so, 7.0/46 no longer applies. As part of this change,
573        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
574        pattern has explicit CR or LF references.
576    29. Added (*CR) etc for changing newline setting at start of pattern.
579    Version 7.2 19-Jun-07
580    ---------------------
582     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
583        which is apparently normally available under Windows.
585     2. Re-jig the pcregrep tests with different newline settings in an attempt
586        to make them independent of the local environment's newline setting.
588     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
590     4. Some of the "internals" tests were previously cut out when the link size
591        was not 2, because the output contained actual offsets. The recent new
592        "Z" feature of pcretest means that these can be cut out, making the tests
593        usable with all link sizes.
595     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
596        stack recursion. This gives a massive performance boost under BSD, but just
597        a small improvement under Linux. However, it saves one field in the frame
598        in all cases.
600     6. Added more features from the forthcoming Perl 5.10:
602        (a) (?-n) (where n is a string of digits) is a relative subroutine or
603            recursion call. It refers to the nth most recently opened parentheses.
605        (b) (?+n) is also a relative subroutine call; it refers to the nth next
606            to be opened parentheses.
608        (c) Conditions that refer to capturing parentheses can be specified
609            relatively, for example, (?(-2)... or (?(+3)...
611        (d) \K resets the start of the current match so that everything before
612            is not part of it.
614        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
616        (f) \g{name} is another synonym - part of Perl 5.10's unification of
617            reference syntax.
619        (g) (?| introduces a group in which the numbering of parentheses in each
620            alternative starts with the same number.
622        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
624     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
627     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
628        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
629        for detecting groups that can match an empty string.
631     9. A pattern with a very large number of alternatives (more than several
632        hundred) was running out of internal workspace during the pre-compile
633        phase, where pcre_compile() figures out how much memory will be needed. A
634        bit of new cunning has reduced the workspace needed for groups with
635        alternatives. The 1000-alternative test pattern now uses 12 bytes of
636        workspace instead of running out of the 4096 that are available.
638    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
640    11. Applied patch from Google to remove an optimization that didn't quite work.
641        The report of the bug said:
643          pcrecpp::RE("a*").FullMatch("aaa") matches, while
644          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
645          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
647    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
648        it matched the wrong number of bytes.
651    Version 7.1 24-Apr-07
652    ---------------------
654     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
655        that is more "standard", making use of automake and other Autotools. There
656        is some re-arrangement of the files and adjustment of comments consequent
657        on this.
659     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
660        for recursive directory scanning broke on some systems because the files
661        are not scanned in any specific order and on different systems the order
662        was different. A call to "sort" has been inserted into RunGrepTest for the
663        approprate test as a short-term fix. In the longer term there may be an
664        alternative.
666     3. I had an email from Eric Raymond about problems translating some of PCRE's
667        man pages to HTML (despite the fact that I distribute HTML pages, some
668        people do their own conversions for various reasons). The problems
669        concerned the use of low-level troff macros .br and .in. I have therefore
670        removed all such uses from the man pages (some were redundant, some could
671        be replaced by .nf/.fi pairs). The 132html script that I use to generate
672        HTML has been updated to handle .nf/.fi and to complain if it encounters
673        .br or .in.
675     4. Updated comments in configure.ac that get placed in config.h.in and also
676        arranged for config.h to be included in the distribution, with the name
677        config.h.generic, for the benefit of those who have to compile without
678        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
680     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
681        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
682        makevp.bat for the current PCRE, using the additional files
683        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
685     6. A Windows user reported a minor discrepancy with test 2, which turned out
686        to be caused by a trailing space on an input line that had got lost in his
687        copy. The trailing space was an accident, so I've just removed it.
689     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
690        that is needed.
692     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
693        as "const" (a) because they are and (b) because it helps the PHP
694        maintainers who have recently made a script to detect big data structures
695        in the php code that should be moved to the .rodata section. I remembered
696        to update Builducptable as well, so it won't revert if ucptable.h is ever
697        re-created.
699     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
700        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
701        order to be able to cut out the UTF-8 tables in the latter when UTF-8
702        support is not required. This saves 1.5-2K of code, which is important in
703        some applications.
705        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
706        so as not to refer to the tables, even though these functions will never be
707        called when UTF-8 support is disabled. Otherwise there are problems with a
708        shared library.
710    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
712        (a) It was defining its arguments as char * instead of void *.
714        (b) It was assuming that all moves were upwards in memory; this was true
715            a long time ago when I wrote it, but is no longer the case.
717        The emulated memove() is provided for those environments that have neither
718        memmove() nor bcopy(). I didn't think anyone used it these days, but that
719        is clearly not the case, as these two bugs were recently reported.
721    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
722        and Detrail to create the HTML documentation, the .txt form of the man
723        pages, and it removes trailing spaces from listed files. It also creates
724        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
725        case, it wraps all the #defines with #ifndefs. This script should be run
726        before "make dist".
728    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
729        with Unicode property support.
731        (a) For a maximizing quantifier, if the two different cases of the
732            character were of different lengths in their UTF-8 codings (there are
733            some cases like this - I found 11), and the matching function had to
734            back up over a mixture of the two cases, it incorrectly assumed they
735            were both the same length.
737        (b) When PCRE was configured to use the heap rather than the stack for
738            recursion during matching, it was not correctly preserving the data for
739            the other case of a UTF-8 character when checking ahead for a match
740            while processing a minimizing repeat. If the check also involved
741            matching a wide character, but failed, corruption could cause an
742            erroneous result when trying to check for a repeat of the original
743            character.
745    13. Some tidying changes to the testing mechanism:
747        (a) The RunTest script now detects the internal link size and whether there
748            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
749            values substituted by "configure". (The RunGrepTest script already did
750            this for UTF-8.) The configure.ac script no longer substitutes the
751            relevant variables.
753        (b) The debugging options /B and /D in pcretest show the compiled bytecode
754            with length and offset values. This means that the output is different
755            for different internal link sizes. Test 2 is skipped for link sizes
756            other than 2 because of this, bypassing the problem. Unfortunately,
757            there was also a test in test 3 (the locale tests) that used /B and
758            failed for link sizes other than 2. Rather than cut the whole test out,
759            I have added a new /Z option to pcretest that replaces the length and
760            offset values with spaces. This is now used to make test 3 independent
761            of link size. (Test 2 will be tidied up later.)
763    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
764        segmentation fault instead of returning the appropriate error message.
766    15. In multiline mode when the newline sequence was set to "any", the pattern
767        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
768        This doesn't seem right; it now treats the CRLF combination as the line
769        ending, and so does not match in that case. It's only a pattern such as ^$
770        that would hit this one: something like ^ABC$ would have failed after \r
771        and then tried again after \r\n.
773    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
774        in an attempt to make files that differ only in their line terminators
775        compare equal. This works on Linux.
777    17. Under certain error circumstances pcregrep might try to free random memory
778        as it exited. This is now fixed, thanks to valgrind.
780    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
781        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
782        was because its rules for how to advance for /g after matching an empty
783        string at the end of a line did not allow for this case. They now check for
784        it specially.
786    20. pcretest is supposed to handle patterns and data of any length, by
787        extending its buffers when necessary. It was getting this wrong when the
788        buffer for a data line had to be extended.
790    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
791        CRLF as a newline sequence.
793    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
794        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
795        I have nevertheless tidied it up.
797    23. Added some casts to kill warnings from HP-UX ia64 compiler.
799    24. Added a man page for pcre-config.
802    Version 7.0 19-Dec-06
803    ---------------------
805     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
806        moving to gcc 4.1.1.
808     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
809        sys/time.h, which is documented as needed for this function. It doesn't
810        seem to matter on Linux, but it showed up on some releases of OS X.
812     3. It seems that there are systems where bytes whose values are greater than
813        127 match isprint() in the "C" locale. The "C" locale should be the
814        default when a C program starts up. In most systems, only ASCII printing
815        characters match isprint(). This difference caused the output from pcretest
816        to vary, making some of the tests fail. I have changed pcretest so that:
818        (a) When it is outputting text in the compiled version of a pattern, bytes
819            other than 32-126 are always shown as hex escapes.
821        (b) When it is outputting text that is a matched part of a subject string,
822            it does the same, unless a different locale has been set for the match
823            (using the /L modifier). In this case, it uses isprint() to decide.
825     4. Fixed a major bug that caused incorrect computation of the amount of memory
826        required for a compiled pattern when options that changed within the
827        pattern affected the logic of the preliminary scan that determines the
828        length. The relevant options are -x, and -i in UTF-8 mode. The result was
829        that the computed length was too small. The symptoms of this bug were
830        either the PCRE error "internal error: code overflow" from pcre_compile(),
831        or a glibc crash with a message such as "pcretest: free(): invalid next
832        size (fast)". Examples of patterns that provoked this bug (shown in
833        pcretest format) are:
835          /(?-x: )/x
836          /(?x)(?-x: \s*#\s*)/
837          /((?i)[\x{c0}])/8
838          /(?i:[\x{c0}])/8
840        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
841        is now done differently.
843     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
844        wrapper classes; (b) implement a new function in the C++ scanner that is
845        more efficient than the old way of doing things because it avoids levels of
846        recursion in the regex matching; (c) add a paragraph to the documentation
847        for the FullMatch() function.
849     6. The escape sequence \n was being treated as whatever was defined as
850        "newline". Not only was this contrary to the documentation, which states
851        that \n is character 10 (hex 0A), but it also went horribly wrong when
852        "newline" was defined as CRLF. This has been fixed.
854     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
855        was being set to -1 for the "end of line" case (supposedly a value that no
856        character can have). Though this value is never used (the check for end of
857        line is "zero bytes in current character"), it caused compiler complaints.
858        I've changed it to 0xffffffff.
860     8. In pcre_version.c, the version string was being built by a sequence of
861        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
862        string (as it is for production releases) called a macro with an empty
863        argument. The C standard says the result of this is undefined. The gcc
864        compiler treats it as an empty string (which was what was wanted) but it is
865        reported that Visual C gives an error. The source has been hacked around to
866        avoid this problem.
868     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
869        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
870        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
871        of them did).
873    10. Originally, pcretest opened its input and output without "b"; then I was
874        told that "b" was needed in some environments, so it was added for release
875        5.0 to both the input and output. (It makes no difference on Unix-like
876        systems.) Later I was told that it is wrong for the input on Windows. I've
877        now abstracted the modes into two macros, to make it easier to fiddle with
878        them, and removed "b" from the input mode under Windows.
880    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
882    12. Added -help and --help to pcretest as an official way of being reminded
883        of the options.
885    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
886        and pcrecpp.cc because they annoy compilers at high warning levels.
888    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
890    15. Fixed an occurrence of == in configure.ac that should have been = (shell
891        scripts are not C programs :-) and which was not noticed because it works
892        on Linux.
894    16. pcretest is supposed to handle any length of pattern and data line (as one
895        line or as a continued sequence of lines) by extending its input buffer if
896        necessary. This feature was broken for very long pattern lines, leading to
897        a string of junk being passed to pcre_compile() if the pattern was longer
898        than about 50K.
900    17. I have done a major re-factoring of the way pcre_compile() computes the
901        amount of memory needed for a compiled pattern. Previously, there was code
902        that made a preliminary scan of the pattern in order to do this. That was
903        OK when PCRE was new, but as the facilities have expanded, it has become
904        harder and harder to keep it in step with the real compile phase, and there
905        have been a number of bugs (see for example, 4 above). I have now found a
906        cunning way of running the real compile function in a "fake" mode that
907        enables it to compute how much memory it would need, while actually only
908        ever using a few hundred bytes of working memory and without too many
909        tests of the mode. This should make future maintenance and development
910        easier. A side effect of this work is that the limit of 200 on the nesting
911        depth of parentheses has been removed (though this was never a serious
912        limitation, I suspect). However, there is a downside: pcre_compile() now
913        runs more slowly than before (30% or more, depending on the pattern). I
914        hope this isn't a big issue. There is no effect on runtime performance.
916    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
917        newline (only possible for the last line of a file) and it was a
918        pattern that set a locale (followed by /Lsomething), pcretest crashed.
920    19. Added additional timing features to pcretest. (1) The -tm option now times
921        matching only, not compiling. (2) Both -t and -tm can be followed, as a
922        separate command line item, by a number that specifies the number of
923        repeats to use when timing. The default is 50000; this gives better
924        precision, but takes uncomfortably long for very large patterns.
926    20. Extended pcre_study() to be more clever in cases where a branch of a
927        subpattern has no definite first character. For example, (a*|b*)[cd] would
928        previously give no result from pcre_study(). Now it recognizes that the
929        first character must be a, b, c, or d.
931    21. There was an incorrect error "recursive call could loop indefinitely" if
932        a subpattern (or the entire pattern) that was being tested for matching an
933        empty string contained only one non-empty item after a nested subpattern.
934        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
935        incorrectly, because the \d was being skipped in the check.
937    22. The pcretest program now has a new pattern option /B and a command line
938        option -b, which is equivalent to adding /B to every pattern. This causes
939        it to show the compiled bytecode, without the additional information that
940        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
941        is the same as /B/I).
943    23. A new optimization is now able automatically to treat some sequences such
944        as a*b as a*+b. More specifically, if something simple (such as a character
945        or a simple class like \d) has an unlimited quantifier, and is followed by
946        something that cannot possibly match the quantified thing, the quantifier
947        is automatically "possessified".
949    24. A recursive reference to a subpattern whose number was greater than 39
950        went wrong under certain circumstances in UTF-8 mode. This bug could also
951        have affected the operation of pcre_study().
953    25. Realized that a little bit of performance could be had by replacing
954        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
956    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
958    27. Possessive quantifiers such as a++ were previously implemented by turning
959        them into atomic groups such as ($>a+). Now they have their own opcodes,
960        which improves performance. This includes the automatically created ones
961        from 23 above.
963    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
964        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
965        the first matched character to be a colon. This applied both to named and
966        numbered groups.
968    29. The ucpinternal.h header file was missing its idempotency #ifdef.
970    30. I was sent a "project" file called libpcre.a.dev which I understand makes
971        building PCRE on Windows easier, so I have included it in the distribution.
973    31. There is now a check in pcretest against a ridiculously large number being
974        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
975        loop, the loop is abandoned.
977    32. Forward references to subpatterns in conditions such as (?(2)...) where
978        subpattern 2 is defined later cause pcre_compile() to search forwards in
979        the pattern for the relevant set of parentheses. This search went wrong
980        when there were unescaped parentheses in a character class, parentheses
981        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
983    33. "Subroutine" calls and backreferences were previously restricted to
984        referencing subpatterns earlier in the regex. This restriction has now
985        been removed.
987    34. Added a number of extra features that are going to be in Perl 5.10. On the
988        whole, these are just syntactic alternatives for features that PCRE had
989        previously implemented using the Python syntax or my own invention. The
990        other formats are all retained for compatibility.
992        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
993            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
994            also .NET compatible.
996        (b) A recursion or subroutine call to a named group can now be defined as
997            (?&name) as well as (?P>name).
999        (c) A backreference to a named group can now be defined as \k<name> or
1000            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1001            5.10, are also .NET compatible.
1003        (d) A conditional reference to a named group can now use the syntax
1004            (?(<name>) or (?('name') as well as (?(name).
1006        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1007            groups (named and numbered) that are never evaluated inline, but can be
1008            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1009            is always false. There may be only one alternative in such a group.
1011        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1012            as the simple (?(R). The condition is true only if the most recent
1013            recursion is that of the given number or name. It does not search out
1014            through the entire recursion stack.
1016        (g) The escape \gN or \g{N} has been added, where N is a positive or
1017            negative number, specifying an absolute or relative reference.
1019    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1020        some "unreachable code" warnings.
1022    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1023        things, this adds five new scripts.
1025    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1026        There were also incompatibilities regarding the handling of \Q..\E inside
1027        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1028        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1030    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1031        matches an empty string, and forcibly breaks the loop. There were bugs in
1032        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1033        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1034        separate and independent bugs (that affected different cases) have been
1035        fixed.
1037    39. Refactored the code to abolish the use of different opcodes for small
1038        capturing bracket numbers. This is a tidy that I avoided doing when I
1039        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1040        The new approach is not only tidier, it makes it possible to reduce the
1041        memory needed to fix the previous bug (38).
1043    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1044        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1045        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1046        mode.
1048    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1049        report.
1051    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1052        copy construction and assignment in the C++ wrapper.
1054    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1055        couple of bugs that could have given wrong results in the "--newline=crlf"
1056        case.
1058    44. Added a number of casts and did some reorganization of signed/unsigned int
1059        variables following suggestions from Dair Grant. Also renamed the variable
1060        "this" as "item" because it is a C++ keyword.
1062    45. Arranged for dftables to add
1064          #include "pcre_internal.h"
1066        to pcre_chartables.c because without it, gcc 4.x may remove the array
1067        definition from the final binary if PCRE is built into a static library and
1068        dead code stripping is activated.
1070    46. For an unanchored pattern, if a match attempt fails at the start of a
1071        newline sequence, and the newline setting is CRLF or ANY, and the next two
1072        characters are CRLF, advance by two characters instead of one.
1075    Version 6.7 04-Jul-06
1076    ---------------------
1078     1. In order to handle tests when input lines are enormously long, pcretest has
1079        been re-factored so that it automatically extends its buffers when
1080        necessary. The code is crude, but this _is_ just a test program. The
1081        default size has been increased from 32K to 50K.
1083     2. The code in pcre_study() was using the value of the re argument before
1084        testing it for NULL. (Of course, in any sensible call of the function, it
1085        won't be NULL.)
1087     3. The memmove() emulation function in pcre_internal.h, which is used on
1088        systems that lack both memmove() and bcopy() - that is, hardly ever -
1089        was missing a "static" storage class specifier.
1091     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1092        containing an extended class (one that cannot be represented by a bitmap
1093        because it contains high-valued characters or Unicode property items, e.g.
1094        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1095        pattern, but PCRE should not loop if you do not (it no longer does).
1096        [Detail: two cases were found: (a) a repeated subpattern containing an
1097        extended class; (b) a recursive reference to a subpattern that followed a
1098        previous extended class. It wasn't skipping over the extended class
1099        correctly when UTF-8 mode was not set.]
1101     5. A negated single-character class was not being recognized as fixed-length
1102        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1103        compile error "lookbehind assertion is not fixed length".
1105     6. The RunPerlTest auxiliary script was showing an unexpected difference
1106        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1107        write a Perl script that can interpret lines of an input file either as
1108        byte characters or as UTF-8, which is what "perltest" was being required to
1109        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1110        can't do is switch easily at run time between having the "use utf8;" pragma
1111        or not. In the end, I fudged it by using the RunPerlTest script to insert
1112        "use utf8;" explicitly for the UTF-8 tests.
1114     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1115        the end of the subject string, contrary to the documentation and to what
1116        Perl does. This was true of both matching functions. Now it matches only at
1117        the start of the subject and immediately after *internal* newlines.
1119     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1120        a pointer to an int instead of a pointer to an unsigned long int. This
1121        caused problems on 64-bit systems.
1123     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1124        instance of the 'standard' template library not being so standard".
1126    10. There was no check on the number of named subpatterns nor the maximum
1127        length of a subpattern name. The product of these values is used to compute
1128        the size of the memory block for a compiled pattern. By supplying a very
1129        long subpattern name and a large number of named subpatterns, the size
1130        computation could be caused to overflow. This is now prevented by limiting
1131        the length of names to 32 characters, and the number of named subpatterns
1132        to 10,000.
1134    11. Subpatterns that are repeated with specific counts have to be replicated in
1135        the compiled pattern. The size of memory for this was computed from the
1136        length of the subpattern and the repeat count. The latter is limited to
1137        65535, but there was no limit on the former, meaning that integer overflow
1138        could in principle occur. The compiled length of a repeated subpattern is
1139        now limited to 30,000 bytes in order to prevent this.
1141    12. Added the optional facility to have named substrings with the same name.
1143    13. Added the ability to use a named substring as a condition, using the
1144        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1145        are numbers (not recommended). Forward references are permitted.
1147    14. Added forward references in named backreferences (if you see what I mean).
1149    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1150        pattern could run off the end of the subject. For example, the pattern
1151        "(?s)(.{1,5})"8 did this with the subject "ab".
1153    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1154        PCRE_CASELESS was set when matching characters that were quantified with ?
1155        or *.
1157    17. A character class other than a single negated character that had a minimum
1158        but no maximum quantifier - for example [ab]{6,} - was not handled
1159        correctly by pce_dfa_exec(). It would match only one character.
1161    18. A valid (though odd) pattern that looked like a POSIX character
1162        class but used an invalid character after [ (for example [[,abc,]]) caused
1163        pcre_compile() to give the error "Failed: internal error: code overflow" or
1164        in some cases to crash with a glibc free() error. This could even happen if
1165        the pattern terminated after [[ but there just happened to be a sequence of
1166        letters, a binary zero, and a closing ] in the memory that followed.
1168    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1169        over the years. Originally (before any Unicode support), just the bottom 8
1170        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1171        output from "man perlunicode" includes this:
1173          The regular expression compiler produces polymorphic opcodes.  That
1174          is, the pattern adapts to the data and automatically switches to
1175          the Unicode character scheme when presented with Unicode data--or
1176          instead uses a traditional byte scheme when presented with byte
1177          data.
1179        Sadly, a wide octal escape does not cause a switch, and in a string with
1180        no other multibyte characters, these octal escapes are treated as before.
1181        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1182        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1183        Unicode string.
1185        I have not perpetrated such confusion in PCRE. Up till now, it took just
1186        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1187        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1188        translate to the appropriate multibyte character.
1190    29. Applied some refactoring to reduce the number of warnings from Microsoft
1191        and Borland compilers. This has included removing the fudge introduced
1192        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1193        a warning about an unused variable.
1195    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1196        characters since release 4.0, because Perl (from release 5.004) does not.
1197        [Or at least, is documented not to: some releases seem to be in conflict
1198        with the documentation.] However, when a pattern was studied with
1199        pcre_study() and all its branches started with \s, PCRE still included VT
1200        as a possible starting character. Of course, this did no harm; it just
1201        caused an unnecessary match attempt.
1203    22. Removed a now-redundant internal flag bit that recorded the fact that case
1204        dependency changed within the pattern. This was once needed for "required
1205        byte" processing, but is no longer used. This recovers a now-scarce options
1206        bit. Also moved the least significant internal flag bit to the most-
1207        significant bit of the word, which was not previously used (hangover from
1208        the days when it was an int rather than a uint) to free up another bit for
1209        the future.
1211    23. Added support for CRLF line endings as well as CR and LF. As well as the
1212        default being selectable at build time, it can now be changed at runtime
1213        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1214        specify that it is scanning data with non-default line endings.
1216    24. Changed the definition of CXXLINK to make it agree with the definition of
1217        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1219    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1220        recursions. This makes a big different to stack usage for some patterns.
1222    26. If a subpattern containing a named recursion or subroutine reference such
1223        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1224        the space required for the compiled pattern went wrong and gave too small a
1225        value. Depending on the environment, this could lead to "Failed: internal
1226        error: code overflow at offset 49" or "glibc detected double free or
1227        corruption" errors.
1229    27. Applied patches from Google (a) to support the new newline modes and (b) to
1230        advance over multibyte UTF-8 characters in GlobalReplace.
1232    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1233        difference for some implementation of PCRE in some Windows version.
1235    29. Added some extra testing facilities to pcretest:
1237        \q<number>   in a data line sets the "match limit" value
1238        \Q<number>   in a data line sets the "match recursion limt" value
1239        -S <number>  sets the stack size, where <number> is in megabytes
1241        The -S option isn't available for Windows.
1244    Version 6.6 06-Feb-06
1245    ---------------------
1247     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1248        in pcreposix.h. I have copied the definition from pcre.h.
1250     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1251        because pcre.h is no longer a built file.
1253     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1254        not normally included in the compiled code.
1257    Version 6.5 01-Feb-06
1258    ---------------------
1260     1. When using the partial match feature with pcre_dfa_exec(), it was not
1261        anchoring the second and subsequent partial matches at the new starting
1262        point. This could lead to incorrect results. For example, with the pattern
1263        /1234/, partially matching against "123" and then "a4" gave a match.
1265     2. Changes to pcregrep:
1267        (a) All non-match returns from pcre_exec() were being treated as failures
1268            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1269            error message is output. Some extra information is given for the
1270            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1271            probably the only errors that are likely to be caused by users (by
1272            specifying a regex that has nested indefinite repeats, for instance).
1273            If there are more than 20 of these errors, pcregrep is abandoned.
1275        (b) A binary zero was treated as data while matching, but terminated the
1276            output line if it was written out. This has been fixed: binary zeroes
1277            are now no different to any other data bytes.
1279        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1280            used to set a locale for matching. The --locale=xxxx long option has
1281            been added (no short equivalent) to specify a locale explicitly on the
1282            pcregrep command, overriding the environment variables.
1284        (d) When -B was used with -n, some line numbers in the output were one less
1285            than they should have been.
1287        (e) Added the -o (--only-matching) option.
1289        (f) If -A or -C was used with -c (count only), some lines of context were
1290            accidentally printed for the final match.
1292        (g) Added the -H (--with-filename) option.
1294        (h) The combination of options -rh failed to suppress file names for files
1295            that were found from directory arguments.
1297        (i) Added the -D (--devices) and -d (--directories) options.
1299        (j) Added the -F (--fixed-strings) option.
1301        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1303        (l) Added the --colo(u)r option.
1305        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1306            is not present by default.
1308     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1309        items such as (?R) or (?1), when the recursion could match a number of
1310        alternatives. If it matched one of the alternatives, but subsequently,
1311        outside the recursion, there was a failure, the code tried to back up into
1312        the recursion. However, because of the way PCRE is implemented, this is not
1313        possible, and the result was an incorrect result from the match.
1315        In order to prevent this happening, the specification of recursion has
1316        been changed so that all such subpatterns are automatically treated as
1317        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1319     4. I had overlooked the fact that, in some locales, there are characters for
1320        which isalpha() is true but neither isupper() nor islower() are true. In
1321        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1322        and ordfeminine) are like this. This affected the treatment of \w and \W
1323        when they appeared in character classes, but not when they appeared outside
1324        a character class. The bit map for "word" characters is now created
1325        separately from the results of isalnum() instead of just taking it from the
1326        upper, lower, and digit maps. (Plus the underscore character, of course.)
1328     5. The above bug also affected the handling of POSIX character classes such as
1329        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1330        permanent tables. Instead, the bit maps for such a class were previously
1331        created as the appropriate unions of the upper, lower, and digit bitmaps.
1332        Now they are created by subtraction from the [[:word:]] class, which has
1333        its own bitmap.
1335     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1336        It is created by subtracting the vertical space characters (\x09, \x0a,
1337        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1338        subtraction was done in the overall bitmap for a character class, meaning
1339        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1340        be recognized. This bug has been fixed.
1342     7. Patches from the folks at Google:
1344          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1345          real life, but is still worth protecting against".
1347          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1348          regular expressions".
1350          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1351          have it.
1353          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1354          "configure" and the latter not, in order to fix a problem somebody had
1355          with compiling the Arg class on HP-UX.
1357          (e) Improve the error-handling of the C++ wrapper a little bit.
1359          (f) New tests for checking recursion limiting.
1361     8. The pcre_memmove() function, which is used only if the environment does not
1362        have a standard memmove() function (and is therefore rarely compiled),
1363        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1364        returning a result (though PCRE never actually uses the result).
1366     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1367        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1368        returned instead of calling malloc() with an overflowing number that would
1369        most likely cause subsequent chaos.
1371    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1373    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1374        with this option is matched, the nmatch and pmatch options of regexec() are
1375        ignored.
1377    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1378        provided in case anyone wants to the the POSIX interface with UTF-8
1379        strings.
1381    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1382        C++ linking (needed for some HP-UX environments).
1384    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1385        (unused parameter) and in the pcre_printint() function (omitted "default"
1386        switch label when the default is to do nothing).
1388    15. Added some code to make it possible, when PCRE is compiled as a C++
1389        library, to replace subject pointers for pcre_exec() with a smart pointer
1390        class, thus making it possible to process discontinuous strings.
1392    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1393        much the same function. They were added by different people who were trying
1394        to make PCRE easy to compile on non-Unix systems. It has been suggested
1395        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1396        for compiling on Windows systems. I have therefore replaced it with
1397        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1398        defaults to "extern" for C or "extern C" for C++, which works fine on
1399        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1400        SCOPE with something explicit in config.h. In addition:
1402        (a) pcreposix.h still had just "extern" instead of either of these macros;
1403            I have replaced it with PCRE_DATA_SCOPE.
1405        (b) Functions such as _pcre_xclass(), which are internal to the library,
1406            but external in the C sense, all had PCRE_EXPORT in their definitions.
1407            This is apparently wrong for the Windows case, so I have removed it.
1408            (It makes no difference on Unix-like systems.)
1410    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1411        of recursive calls to match(). This is different to MATCH_LIMIT because
1412        that limits the total number of calls to match(), not all of which increase
1413        the depth of recursion. Limiting the recursion depth limits the amount of
1414        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1415        when PCRE is compiled, and changed at run time. A patch from Google adds
1416        this functionality to the C++ interface.
1418    18. Changes to the handling of Unicode character properties:
1420        (a) Updated the table to Unicode 4.1.0.
1422        (b) Recognize characters that are not in the table as "Cn" (undefined).
1424        (c) I revised the way the table is implemented to a much improved format
1425            which includes recognition of ranges. It now supports the ranges that
1426            are defined in UnicodeData.txt, and it also amalgamates other
1427            characters into ranges. This has reduced the number of entries in the
1428            table from around 16,000 to around 3,000, thus reducing its size
1429            considerably. I realized I did not need to use a tree structure after
1430            all - a binary chop search is just as efficient. Having reduced the
1431            number of entries, I extended their size from 6 bytes to 8 bytes to
1432            allow for more data.
1434        (d) Added support for Unicode script names via properties such as \p{Han}.
1436    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1437        matching that character.
1439    20. When matching a repeated Unicode property with a minimum greater than zero,
1440        (for example \pL{2,}), PCRE could look past the end of the subject if it
1441        reached it while seeking the minimum number of characters. This could
1442        happen only if some of the characters were more than one byte long, because
1443        there is a check for at least the minimum number of bytes.
1445    21. Refactored the implementation of \p and \P so as to be more general, to
1446        allow for more different types of property in future. This has changed the
1447        compiled form incompatibly. Anybody with saved compiled patterns that use
1448        \p or \P will have to recompile them.
1450    22. Added "Any" and "L&" to the supported property types.
1452    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1453        but give a compile time error if the value is greater than 0xff.
1455    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1456        accidentally not being installed or uninstalled.
1458    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1459        made were to insert the current release number. This seemed silly, because
1460        it made things harder for people building PCRE on systems that don't run
1461        "configure". I have turned pcre.h into a distributed file, no longer built
1462        by "configure", with the version identification directly included. There is
1463        no longer a pcre.h.in file.
1465        However, this change necessitated a change to the pcre-config script as
1466        well. It is built from pcre-config.in, and one of the substitutions was the
1467        release number. I have updated configure.ac so that ./configure now finds
1468        the release number by grepping pcre.h.
1470    26. Added the ability to run the tests under valgrind.
1473    Version 6.4 05-Sep-05
1474    ---------------------
1476     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1477        "--" to be printed when multiple files were scanned, even when none of the
1478        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1479        consider it to be a bug, and have restored the previous behaviour.
1481     2. A couple of code tidies to get rid of compiler warnings.
1483     3. The pcretest program used to cheat by referring to symbols in the library
1484        whose names begin with _pcre_. These are internal symbols that are not
1485        really supposed to be visible externally, and in some environments it is
1486        possible to suppress them. The cheating is now confined to including
1487        certain files from the library's source, which is a bit cleaner.
1489     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1490        file's purpose clearer.
1492     5. Reorganized pcre_ucp_findchar().
1495    Version 6.3 15-Aug-05
1496    ---------------------
1498     1. The file libpcre.pc.in did not have general read permission in the tarball.
1500     2. There were some problems when building without C++ support:
1502        (a) If C++ support was not built, "make install" and "make test" still
1503            tried to test it.
1505        (b) There were problems when the value of CXX was explicitly set. Some
1506            changes have been made to try to fix these, and ...
1508        (c) --disable-cpp can now be used to explicitly disable C++ support.
1510        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1511            backslash in a target when C++ was disabled. This confuses some
1512            versions of "make", apparently. Using an intermediate variable solves
1513            this. (Same for CPP_LOBJ.)
1515     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1516        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1517        necessary on certain architectures.
1519     4. Added a setting of -export-symbols-regex to the link command to remove
1520        those symbols that are exported in the C sense, but actually are local
1521        within the library, and not documented. Their names all begin with
1522        "_pcre_". This is not a perfect job, because (a) we have to except some
1523        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1524        available (and never for static libraries). I have made a note to try to
1525        find a way round (a) in the future.
1528    Version 6.2 01-Aug-05
1529    ---------------------
1531     1. There was no test for integer overflow of quantifier values. A construction
1532        such as {1111111111111111} would give undefined results. What is worse, if
1533        a minimum quantifier for a parenthesized subpattern overflowed and became
1534        negative, the calculation of the memory size went wrong. This could have
1535        led to memory overwriting.
1537     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1539     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1540        operating environments where this matters.
1542     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1543        PCRE options from within the C++ wrapper.
1545     5. Named capturing subpatterns were not being correctly counted when a pattern
1546        was compiled. This caused two problems: (a) If there were more than 100
1547        such subpatterns, the calculation of the memory needed for the whole
1548        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1549        back references of the form \12, where the number was greater than 9, were
1550        not recognized as back references, even though there were sufficient
1551        previous subpatterns.
1553     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1554        versions of gcc, e.g. 2.95.4.
1557    Version 6.1 21-Jun-05
1558    ---------------------
1560     1. There was one reference to the variable "posix" in pcretest.c that was not
1561        surrounded by "#if !defined NOPOSIX".
1563     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1564        the cross-check on the old pcre_info() function, for the benefit of the
1565        cut-down version of PCRE that is currently imported into Exim.
1567     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1568        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1569        patterns that start (?i) but I don't think that matters. The use of (?i) is
1570        just an example; this all applies to the other options as well.
1572     4. Since libtool seems to echo the compile commands it is issuing, the output
1573        from "make" can be reduced a bit by putting "@" in front of each libtool
1574        compile command.
1576     5. Patch from the folks at Google for configure.in to be a bit more thorough
1577        in checking for a suitable C++ installation before trying to compile the
1578        C++ stuff. This should fix a reported problem when a compiler was present,
1579        but no suitable headers.
1581     6. The man pages all had just "PCRE" as their title. I have changed them to
1582        be the relevant file name. I have also arranged that these names are
1583        retained in the file doc/pcre.txt, which is a concatenation in text format
1584        of all the man pages except the little individual ones for each function.
1586     7. The NON-UNIX-USE file had not been updated for the different set of source
1587        files that come with release 6. I also added a few comments about the C++
1588        wrapper.
1591    Version 6.0 07-Jun-05
1592    ---------------------
1594     1. Some minor internal re-organization to help with my DFA experiments.
1596     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1597        didn't matter for the library itself when fully configured, but did matter
1598        when compiling without UCP support, or within Exim, where the ucp files are
1599        not imported.
1601     3. Refactoring of the library code to split up the various functions into
1602        different source modules. The addition of the new DFA matching code (see
1603        below) to a single monolithic source would have made it really too
1604        unwieldy, quite apart from causing all the code to be include in a
1605        statically linked application, when only some functions are used. This is
1606        relevant even without the DFA addition now that patterns can be compiled in
1607        one application and matched in another.
1609        The downside of splitting up is that there have to be some external
1610        functions and data tables that are used internally in different modules of
1611        the library but which are not part of the API. These have all had their
1612        names changed to start with "_pcre_" so that they are unlikely to clash
1613        with other external names.
1615     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1616        a different (DFA) algorithm. Although it is slower than the original
1617        function, it does have some advantages for certain types of matching
1618        problem.
1620     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1621        including restarting after a partial match.
1623     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1624        defined when compiling for Windows was sent to me. I have put it into the
1625        code, though I have no means of testing or verifying it.
1627     7. Added the pcre_refcount() auxiliary function.
1629     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1630        match before or at the first newline in the subject string. In pcretest,
1631        the /f option on a pattern can be used to set this.
1633     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1634        would behave wrongly. This has been present in PCRE since release 4.0.
1636    10. A number of changes to the pcregrep command:
1638        (a) Refactored how -x works; insert ^(...)$ instead of setting
1639            PCRE_ANCHORED and checking the length, in preparation for adding
1640            something similar for -w.
1642        (b) Added the -w (match as a word) option.
1644        (c) Refactored the way lines are read and buffered so as to have more
1645            than one at a time available.
1647        (d) Implemented a pcregrep test script.
1649        (e) Added the -M (multiline match) option. This allows patterns to match
1650            over several lines of the subject. The buffering ensures that at least
1651            8K, or the rest of the document (whichever is the shorter) is available
1652            for matching (and similarly the previous 8K for lookbehind assertions).
1654        (f) Changed the --help output so that it now says
1656              -w, --word-regex(p)
1658            instead of two lines, one with "regex" and the other with "regexp"
1659            because that confused at least one person since the short forms are the
1660            same. (This required a bit of code, as the output is generated
1661            automatically from a table. It wasn't just a text change.)
1663        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1664            option but starts with a hyphen. Could be a pattern or a path name
1665            starting with a hyphen, for instance.
1667        (h) "-" can be given as a file name to represent stdin.
1669        (i) When file names are being printed, "(standard input)" is used for
1670            the standard input, for compatibility with GNU grep. Previously
1671            "<stdin>" was used.
1673        (j) The option --label=xxx can be used to supply a name to be used for
1674            stdin when file names are being printed. There is no short form.
1676        (k) Re-factored the options decoding logic because we are going to add
1677            two more options that take data. Such options can now be given in four
1678            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1680        (l) Added the -A, -B, and -C options for requesting that lines of context
1681            around matches be printed.
1683        (m) Added the -L option to print the names of files that do not contain
1684            any matching lines, that is, the complement of -l.
1686        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1687            continue to scan other files.
1689        (o) The -s option was incorrectly implemented. For compatibility with other
1690            greps, it now suppresses the error message for a non-existent or non-
1691            accessible file (but not the return code). There is a new option called
1692            -q that suppresses the output of matching lines, which was what -s was
1693            previously doing.
1695        (p) Added --include and --exclude options to specify files for inclusion
1696            and exclusion when recursing.
1698    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1699        Hopefully, it now does.
1701    12. Missing cast in pcre_study().
1703    13. Added an "uninstall" target to the makefile.
1705    14. Replaced "extern" in the function prototypes in Makefile.in with
1706        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1707        world, but is set differently for Windows.
1709    15. Added a second compiling function called pcre_compile2(). The only
1710        difference is that it has an extra argument, which is a pointer to an
1711        integer error code. When there is a compile-time failure, this is set
1712        non-zero, in addition to the error test pointer being set to point to an
1713        error message. The new argument may be NULL if no error number is required
1714        (but then you may as well call pcre_compile(), which is now just a
1715        wrapper). This facility is provided because some applications need a
1716        numeric error indication, but it has also enabled me to tidy up the way
1717        compile-time errors are handled in the POSIX wrapper.
1719    16. Added VPATH=.libs to the makefile; this should help when building with one
1720        prefix path and installing with another. (Or so I'm told by someone who
1721        knows more about this stuff than I do.)
1723    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1724        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1725        match everything, including newlines. This is not POSIX-compatible, but
1726        somebody wanted the feature. From pcretest it can be activated by using
1727        both the P and the s flags.
1729    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1731    19. libpcre.pc was being incorrectly installed as executable.
1733    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1734        it now also looks for '\r' so that it will work unmodified on Windows.
1736    21. Added Google's contributed C++ wrapper to the distribution.
1738    22. Added some untidy missing memory free() calls in pcretest, to keep
1739        Electric Fence happy when testing.
1743    Version 5.0 13-Sep-04
1744    ---------------------
1746     1. Internal change: literal characters are no longer packed up into items
1747        containing multiple characters in a single byte-string. Each character
1748        is now matched using a separate opcode. However, there may be more than one
1749        byte in the character in UTF-8 mode.
1751     2. The pcre_callout_block structure has two new fields: pattern_position and
1752        next_item_length. These contain the offset in the pattern to the next match
1753        item, and its length, respectively.
1755     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1756        insertion of callouts before each pattern item. Added the /C option to
1757        pcretest to make use of this.
1759     4. On the advice of a Windows user, the lines
1761          #if defined(_WIN32) || defined(WIN32)
1762          _setmode( _fileno( stdout ), 0x8000 );
1763          #endif  /* defined(_WIN32) || defined(WIN32) */
1765        have been added to the source of pcretest. This apparently does useful
1766        magic in relation to line terminators.
1768     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1769        for the benefit of those environments where the "b" makes a difference.
1771     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1772        to know about it. I have put a hack into configure.in that adds in code
1773        to set GCC=yes if CC=icc. This seems to end up at a point in the
1774        generated configure script that is early enough to affect the setting of
1775        compiler options, which is what is needed, but I have no means of testing
1776        whether it really works. (The user who reported this had patched the
1777        generated configure script, which of course I cannot do.)
1779        LATER: After change 22 below (new libtool files), the configure script
1780        seems to know about icc (and also ecc). Therefore, I have commented out
1781        this hack in configure.in.
1783     7. Added support for pkg-config (2 patches were sent in).
1785     8. Negated POSIX character classes that used a combination of internal tables
1786        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1787        [[:^ascii]]. Typically, they would match almost any characters. The other
1788        POSIX classes were not broken in this way.
1790     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1791        to find the match, as PCRE was deluded into thinking that the match had to
1792        start at the start point or following a newline. The same bug applied to
1793        patterns with negative forward assertions or any backward assertions
1794        preceding ".*" at the start, unless the pattern required a fixed first
1795        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1797    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1798        starting at the last subject character, bytes beyond the end of the subject
1799        string were read.
1801    11. Renamed the variable "class" as "classbits" to make life easier for C++
1802        users. (Previously there was a macro definition, but it apparently wasn't
1803        enough.)
1805    12. Added the new field "tables" to the extra data so that tables can be passed
1806        in at exec time, or the internal tables can be re-selected. This allows
1807        a compiled regex to be saved and re-used at a later time by a different
1808        program that might have everything at different addresses.
1810    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1811        -R library as well as a -L library.
1813    14. The debugging options of pcretest (-d on the command line or D on a
1814        pattern) showed incorrect output for anything following an extended class
1815        that contained multibyte characters and which was followed by a quantifier.
1817    15. Added optional support for general category Unicode character properties
1818        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1819        support. It adds about 90K to the size of the library. The meanings of the
1820        inbuilt class escapes such as \d and \s have NOT been changed.
1822    16. Updated pcredemo.c to include calls to free() to release the memory for the
1823        compiled pattern.
1825    17. The generated file chartables.c was being created in the source directory
1826        instead of in the building directory. This caused the build to fail if the
1827        source directory was different from the building directory, and was
1828        read-only.
1830    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1831        file. No doubt somebody will tell me if they don't make sense... Also added
1832        Dan Mooney's comments about building on OpenVMS.
1834    19. Added support for partial matching via the PCRE_PARTIAL option for
1835        pcre_exec() and the \P data escape in pcretest.
1837    20. Extended pcretest with 3 new pattern features:
1839        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1840              write the compiled pattern to the file whose name is "rest-of-line".
1841              This is a straight binary dump of the data, with the saved pointer to
1842              the character tables forced to be NULL. The study data, if any, is
1843              written too. After writing, pcretest reads a new pattern.
1845        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1846              compiled pattern from the given file. There must not be any
1847              occurrences of "<" in the file name (pretty unlikely); if there are,
1848              pcretest will instead treat the initial "<" as a pattern delimiter.
1849              After reading in the pattern, pcretest goes on to read data lines as
1850              usual.
1852        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1853              and 16-bit fields in a compiled pattern, to simulate a pattern that
1854              was compiled on a host of opposite endianness.
1856    21. The pcre-exec() function can now cope with patterns that were compiled on
1857        hosts of opposite endianness, with this restriction:
1859          As for any compiled expression that is saved and used later, the tables
1860          pointer field cannot be preserved; the extra_data field in the arguments
1861          to pcre_exec() should be used to pass in a tables address if a value
1862          other than the default internal tables were used at compile time.
1864    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1865        now diagnosed as an error. Previously, most of the time, a negative number
1866        would have been treated as zero, but if in addition "ovector" was passed as
1867        NULL, a crash could occur.
1869    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1870        new versions from the libtool 1.5 distribution (the last one is a copy of
1871        a file called libtool.m4). This seems to have fixed the need to patch
1872        "configure" to support Darwin 1.3 (which I used to do). However, I still
1873        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1874        workstation).
1876    24. Changed the PCRE licence to be the more standard "BSD" licence.
1879    Version 4.5 01-Dec-03
1880    ---------------------
1882     1. There has been some re-arrangement of the code for the match() function so
1883        that it can be compiled in a version that does not call itself recursively.
1884        Instead, it keeps those local variables that need separate instances for
1885        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1886        needs to "recurse". Keeping track of where control must go is done by means
1887        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1888        hide most of the details from the main code, and operates only if
1889        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1890        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1891        operating.
1893        To make it easier for callers to provide specially tailored get/free
1894        functions for this usage, two new functions, pcre_stack_malloc, and
1895        pcre_stack_free, are used. They are always called in strict stacking order,
1896        and the size of block requested is always the same.
1898        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1899        PCRE has been compiled to use the stack or the heap for recursion. The
1900        -C option of pcretest uses this to show which version is compiled.
1902        A new data escape \S, is added to pcretest; it causes the amounts of store
1903        obtained and freed by both kinds of malloc/free at match time to be added
1904        to the output.
1906     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1907        what's available on my current Linux desktop machine.
1909     3. When matching a UTF-8 string, the test for a valid string at the start has
1910        been extended. If start_offset is not zero, PCRE now checks that it points
1911        to a byte that is the start of a UTF-8 character. If not, it returns
1912        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1913        this is necessary because there may be backward assertions in the pattern.
1914        When matching the same subject several times, it may save resources to use
1915        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1917     4. The code for checking the validity of UTF-8 strings has been tightened so
1918        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1919        containing "overlong sequences".
1921     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1922        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1923        should have been "&", but it just so happened that all the cases this let
1924        through by mistake were picked up later in the function.
1926     6. I had used a variable called "isblank" - this is a C99 function, causing
1927        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1929     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1930        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1931        so the version is shown; (c) stop "make test" echoing "./RunTest".
1933     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1935     9. The prototype for memmove() for systems that don't have it was using
1936        size_t, but the inclusion of the header that defines size_t was later. I've
1937        moved the #includes for the C headers earlier to avoid this.
1939    10. Added some adjustments to the code to make it easier to compiler on certain
1940        special systems:
1942          (a) Some "const" qualifiers were missing.
1943          (b) Added the macro EXPORT before all exported functions; by default this
1944              is defined to be empty.
1945          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1946              that it reads its output file name as an argument instead of writing
1947              to the standard output and assuming this can be redirected.
1949    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1950        class containing characters with values greater than 255, PCRE compilation
1951        went into a loop.
1953    12. A recursive reference to a subpattern that was within another subpattern
1954        that had a minimum quantifier of zero caused PCRE to crash. For example,
1955        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1956        recursion. If the recursively-called subpattern itself had a zero repeat,
1957        that was OK.
1959    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1960        buffer into which it was copied (for escape processing) was still set at
1961        1024, so long lines caused crashes.
1963    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1964        "internal error: code overflow...". This applied to any character class
1965        that was followed by a possessive quantifier.
1967    15. Modified the Makefile to add libpcre.la as a prerequisite for
1968        libpcreposix.la because I was told this is needed for a parallel build to
1969        work.
1971    16. If a pattern that contained .* following optional items at the start was
1972        studied, the wrong optimizing data was generated, leading to matching
1973        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1974        matching string must start with a or b or c. The correct conclusion for
1975        this pattern is that a match can start with any character.
1978    Version 4.4 13-Aug-03
1979    ---------------------
1981     1. In UTF-8 mode, a character class containing characters with values between
1982        127 and 255 was not handled correctly if the compiled pattern was studied.
1983        In fixing this, I have also improved the studying algorithm for such
1984        classes (slightly).
1986     2. Three internal functions had redundant arguments passed to them. Removal
1987        might give a very teeny performance improvement.
1989     3. Documentation bug: the value of the capture_top field in a callout is *one
1990        more than* the number of the hightest numbered captured substring.
1992     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1993        in incorrectly linking with a previously installed version. They now link
1994        explicitly with libpcre.la.
1996     5. configure.in no longer needs to recognize Cygwin specially.
1998     6. A problem in pcre.in for Windows platforms is fixed.
2000     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2001        pcretest, it used to include the size of the study block as part of its
2002        output. Unfortunately, the structure contains a field that has a different
2003        size on different hardware architectures. This meant that the tests that
2004        showed this size failed. As the block is currently always of a fixed size,
2005        this information isn't actually particularly useful in pcretest output, so
2006        I have just removed it.
2008     8. Three pre-processor statements accidentally did not start in column 1.
2009        Sadly, there are *still* compilers around that complain, even though
2010        standard C has not required this for well over a decade. Sigh.
2012     9. In pcretest, the code for checking callouts passed small integers in the
2013        callout_data field, which is a void * field. However, some picky compilers
2014        complained about the casts involved for this on 64-bit systems. Now
2015        pcretest passes the address of the small integer instead, which should get
2016        rid of the warnings.
2018    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2019        both compile and run time, and gives an error if an invalid UTF-8 sequence
2020        is found. There is a option for disabling this check in cases where the
2021        string is known to be correct and/or the maximum performance is wanted.
2023    11. In response to a bug report, I changed one line in Makefile.in from
2025            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2026        to
2027            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2029        to look similar to other lines, but I have no way of telling whether this
2030        is the right thing to do, as I do not use Windows. No doubt I'll get told
2031        if it's wrong...
2034    Version 4.3 21-May-03
2035    ---------------------
2037    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2038       Makefile.
2040    2. Some refactoring to improve the quality of the code:
2042       (i)   The utf8_table... variables are now declared "const".
2044       (ii)  The code for \cx, which used the "case flipping" table to upper case
2045             lower case letters, now just substracts 32. This is ASCII-specific,
2046             but the whole concept of \cx is ASCII-specific, so it seems
2047             reasonable.
2049       (iii) PCRE was using its character types table to recognize decimal and
2050             hexadecimal digits in the pattern. This is silly, because it handles
2051             only 0-9, a-f, and A-F, but the character types table is locale-
2052             specific, which means strange things might happen. A private
2053             table is now used for this - though it costs 256 bytes, a table is
2054             much faster than multiple explicit tests. Of course, the standard
2055             character types table is still used for matching digits in subject
2056             strings against \d.
2058       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2059             ending in _t are). So I've renamed it as ESC_tee.
2061    3. The first argument for regexec() in the POSIX wrapper should have been
2062       defined as "const".
2064    4. Changed pcretest to use malloc() for its buffers so that they can be
2065       Electric Fenced for debugging.
2067    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2068       to read one or more bytes before the start of the subject string. Often this
2069       had no effect on PCRE's behaviour, but in some circumstances it could
2070       provoke a segmentation fault.
2072    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2073       to try to read one or more bytes before the start of the subject string.
2075    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2076       UTF-8 support could misbehave in various ways if the subject string
2077       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2078       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2079       back over UTF-8 characters.)
2082    Version 4.2 14-Apr-03
2083    ---------------------
2085    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2087    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2088         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2089         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2090         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2091         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2092           and BUILD_EXEEXT
2093         Note: automatic setting of the BUILD variables is not yet working
2094         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2095           compile-time but not at link-time
2096         [LINK]: use for linking executables only
2097         make different versions for Windows and non-Windows
2098         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2099           libraries
2100         [LINK_FOR_BUILD]: new variable
2101         [OBJEXT]: use throughout
2102         [EXEEXT]: use throughout
2103         <winshared>: new target
2104         <wininstall>: new target
2105         <dftables.o>: use native compiler
2106         <dftables>: use native linker
2107         <install>: handle Windows platform correctly
2108         <clean>: ditto
2109         <check>: ditto
2110         copy DLL to top builddir before testing
2112       As part of these changes, -no-undefined was removed again. This was reported
2113       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2114       in any case.
2116    3. Some tidies to get rid of compiler warnings:
2118       . In the match_data structure, match_limit was an unsigned long int, whereas
2119         match_call_count was an int. I've made them both unsigned long ints.
2121       . In pcretest the fact that a const uschar * doesn't automatically cast to
2122         a void * provoked a warning.
2124       . Turning on some more compiler warnings threw up some "shadow" variables
2125         and a few more missing casts.
2127    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2128       option, a class that contained a single character with a value between 128
2129       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2131    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2132       option, a class that contained several characters, but with at least one
2133       whose value was between 128 and 255 caused PCRE to crash.
2136    Version 4.1 12-Mar-03
2137    ---------------------
2139    1. Compiling with gcc -pedantic found a couple of places where casts were
2140    needed, and a string in dftables.c that was longer than standard compilers are
2141    required to support.
2143    2. Compiling with Sun's compiler found a few more places where the code could
2144    be tidied up in order to avoid warnings.
2146    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2147    first of these names is deprecated in the latest Autoconf in favour of the name
2148    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2149    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2150    analogy I have changed it to CFLAGS_FOR_BUILD.
2152    4. Added -no-undefined to the linking command in the Makefile, because this is
2153    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2154    linking step for the pcreposix library.
2156    5. PCRE was failing to diagnose the case of two named groups with the same
2157    name.
2159    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2160    literal character that is needed in the subject for a match, and scans along to
2161    ensure that it is present before embarking on the full matching process. This
2162    saves time in cases of nested unlimited repeats that are never going to match.
2163    Problem: the scan can take a lot of time if the subject is very long (e.g.
2164    megabytes), thus penalizing straightforward matches. It is now done only if the
2165    amount of subject to be scanned is less than 1000 bytes.
2167    7. A lesser problem with the same optimization is that it was recording the
2168    first character of an anchored pattern as "needed", thus provoking a search
2169    right along the subject, even when the first match of the pattern was going to
2170    fail. The "needed" character is now not set for anchored patterns, unless it
2171    follows something in the pattern that is of non-fixed length. Thus, it still
2172    fulfils its original purpose of finding quick non-matches in cases of nested
2173    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2176    Version 4.0 17-Feb-03
2177    ---------------------
2179    1. If a comment in an extended regex that started immediately after a meta-item
2180    extended to the end of string, PCRE compiled incorrect data. This could lead to
2181    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2183    2. Moved to autoconf 2.53 and libtool 1.4.2.
2185    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2186    the special perltest8 script is no longer needed - all the tests can be run
2187    from a single perltest script.
2189    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2190    by \s. It has now been removed in PCRE. This means it isn't recognized as
2191    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2192    class [:space:] *does* include VT, thereby creating a mess.
2194    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2195    space and tab.
2197    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2198    its new features into the main test script, reducing the number of scripts.
2200    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2201    were backward compatible, and made the (?i) apply to the whole pattern, as if
2202    /i were given. Now it behaves more logically, and applies the option setting
2203    only to what follows. PCRE has been changed to follow suit. However, if it
2204    finds options settings right at the start of the pattern, it extracts them into
2205    the global options, as before. Thus, they show up in the info data.
2207    8. Added support for the \Q...\E escape sequence. Characters in between are
2208    treated as literals. This is slightly different from Perl in that $ and @ are
2209    also handled as literals inside the quotes. In Perl, they will cause variable
2210    interpolation. Note the following examples:
2212        Pattern            PCRE matches      Perl matches
2214        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2215        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2216        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2218    For compatibility with Perl, \Q...\E sequences are recognized inside character
2219    classes as well as outside them.
2221    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2222    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2223    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2224    signed/unsigned warnings.
2226    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2227    option for pcretest, so I've replaced it by a simple function that does just
2228    that job.
2230    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2231    "pcregrep -".
2233    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2234    Java package. This provides some syntactic sugar for simple cases of what my
2235    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2236    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2237    item, you can use this simplified notation. Note that only makes sense with
2238    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2239    greediness, whatever the setting of the PCRE_UNGREEDY option.
2241    13. A change of greediness default within a pattern was not taking effect at
2242    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2243    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2244    was abstracted outside.
2246    14. PCRE now supports the \G assertion. It is true when the current matching
2247    position is at the start point of the match. This differs from \A when the
2248    starting offset is non-zero. Used with the /g option of pcretest (or similar
2249    code), it works in the same way as it does for Perl's /g option. If all
2250    alternatives of a regex begin with \G, the expression is anchored to the start
2251    match position, and the "anchored" flag is set in the compiled expression.
2253    15. Some bugs concerning the handling of certain option changes within patterns
2254    have been fixed. These applied to options other than (?ims). For example,
2255    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2256    been the other way round. Some of this was related to change 7 above.
2258    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2259    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2260    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2261    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2263    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2264    mode. Unlike ".", it always matches newline, whatever the setting of
2265    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2266    assertions. Perl allows it, but it doesn't (in general) work because it can't
2267    calculate the length of the lookbehind. At least, that's the case for Perl
2268    5.8.0 - I've been told they are going to document that it doesn't work in
2269    future.
2271    18. Added an error diagnosis for escapes that PCRE does not support: these are
2272    \L, \l, \N, \P, \p, \U, \u, and \X.
2274    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2275    reading past the end of the pattern in cases such as /[abcd/.
2277    20. PCRE was getting more memory than necessary for patterns with classes that
2278    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2280    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2281    compiling PCRE for use with Virtual Pascal.
2283    22. Small fix to the Makefile to make it work properly if the build is done
2284    outside the source tree.
2286    23. Added a new extension: a condition to go with recursion. If a conditional
2287    subpattern starts with (?(R) the "true" branch is used if recursion has
2288    happened, whereas the "false" branch is used only at the top level.
2290    24. When there was a very long string of literal characters (over 255 bytes
2291    without UTF support, over 250 bytes with UTF support), the computation of how
2292    much memory was required could be incorrect, leading to segfaults or other
2293    strange effects.
2295    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2296    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2297    there was a subsequent back reference to those brackets. This meant that, for
2298    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2299    possible to check for precisely this case. All we can do is abandon the
2300    optimization if .* occurs inside capturing brackets when there are any back
2301    references whatsoever. (See below for a better fix that came later.)
2303    26. The handling of the optimization for finding the first character of a
2304    non-anchored pattern, and for finding a character that is required later in the
2305    match were failing in some cases. This didn't break the matching; it just
2306    failed to optimize when it could. The way this is done has been re-implemented.
2308    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2310    28. Added a new feature that provides some of the functionality that Perl
2311    provides with (?{...}). The facility is termed a "callout". The way it is done
2312    in PCRE is for the caller to provide an optional function, by setting
2313    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2314    global variable. By default it is unset, which disables all calling out. To get
2315    the function called, the regex must include (?C) at appropriate points. This
2316    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2317    This provides a means of identifying different callout points. When PCRE
2318    reaches such a point in the regex, if pcre_callout has been set, the external
2319    function is called. It is provided with data in a structure called
2320    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2321    matching continues; if it returns a non-zero value, the match at the current
2322    point fails. However, backtracking will occur if possible. [This was changed
2323    later and other features added - see item 49 below.]
2325    29. pcretest is upgraded to test the callout functionality. It provides a
2326    callout function that displays information. By default, it shows the start of
2327    the match and the current position in the text. There are some new data escapes
2328    to vary what happens:
2330        \C+         in addition, show current contents of captured substrings
2331        \C-         do not supply a callout function
2332        \C!n        return 1 when callout number n is reached
2333        \C!n!m      return 1 when callout number n is reached for the mth time
2335    30. If pcregrep was called with the -l option and just a single file name, it
2336    output "<stdin>" if a match was found, instead of the file name.
2338    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2339    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2340    pcre_exec(). This saves a malloc/free per call. The default value of
2341    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2342    when configuring.
2344    32. The default maximum size of a compiled pattern is 64K. There have been a
2345    few cases of people hitting this limit. The code now uses macros to handle the
2346    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2347    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2348    configuring. Tests 2 and 5 work only with 2-byte links because they output
2349    debugging information about compiled patterns.
2351    33. Internal code re-arrangements:
2353    (a) Moved the debugging function for printing out a compiled regex into
2354        its own source file (printint.c) and used #include to pull it into
2355        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2356        separate copies.
2358    (b) Defined the list of op-code names for debugging as a macro in
2359        internal.h so that it is next to the definition of the opcodes.
2361    (c) Defined a table of op-code lengths for simpler skipping along compiled
2362        code. This is again a macro in internal.h so that it is next to the
2363        definition of the opcodes.
2365    34. Added support for recursive calls to individual subpatterns, along the
2366    lines of Robin Houston's patch (but implemented somewhat differently).
2368    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2369    allow it to read and process whole directories in Win32. This code was
2370    contributed by Lionel Fourquaux; it has not been tested by me.
2372    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2373    used to name a group. Names consist of alphanumerics and underscores, and must
2374    be unique. Back references use the syntax (?P=name) and recursive calls use
2375    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2376    numbers. The function pcre_fullinfo() can be used after compilation to extract
2377    a name/number map. There are three relevant calls:
2379      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2380      PCRE_INFO_NAMECOUNT            yields the number of entries
2381      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2383    The map is a vector of fixed-size entries. The size of each entry depends on
2384    the length of the longest name used. The first two bytes of each entry are the
2385    group number, most significant byte first. There follows the corresponding
2386    name, zero terminated. The names are in alphabetical order.
2388    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2389    case instead of 255. Making it the same both with and without UTF-8 support
2390    means that the same test output works with both.
2392    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2393    calling malloc() with a zero argument.
2395    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2396    optimization. I've improved things by keeping a bitmap of backreferences with
2397    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2398    fact referenced, the optimization can be applied. It is unlikely that a
2399    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2400    the match to follow \n) will appear inside brackets with a number greater than
2401    31, but if it does, any back reference > 31 suppresses the optimization.
2403    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2404    of disabling numbered capturing parentheses. Any opening parenthesis that is
2405    not followed by ? behaves as if it were followed by ?: but named parentheses
2406    can still be used for capturing (and they will acquire numbers in the usual
2407    way).
2409    41. Redesigned the return codes from the match() function into yes/no/error so
2410    that errors can be passed back from deep inside the nested calls. A malloc
2411    failure while inside a recursive subpattern call now causes the
2412    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2414    42. It is now possible to set a limit on the number of times the match()
2415    function is called in a call to pcre_exec(). This facility makes it possible to
2416    limit the amount of recursion and backtracking, though not in a directly
2417    obvious way, because the match() function is used in a number of different
2418    circumstances. The count starts from zero for each position in the subject
2419    string (for non-anchored patterns). The default limit is, for compatibility, a
2420    large number, namely 10 000 000. You can change this in two ways:
2422    (a) When configuring PCRE before making, you can use --with-match-limit=n
2423        to set a default value for the compiled library.
2425    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2426        a different value is set. See 45 below.
2428    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2430    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2431    of things that can be changed at compile time. The first argument specifies
2432    what is wanted and the second points to where the information is to be placed.
2433    The current list of available information is:
2435      PCRE_CONFIG_UTF8
2437    The output is an integer that is set to one if UTF-8 support is available;
2438    otherwise it is set to zero.
2442    The output is an integer that it set to the value of the code that is used for
2443    newline. It is either LF (10) or CR (13).
2447    The output is an integer that contains the number of bytes used for internal
2448    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2452    The output is an integer that contains the threshold above which the POSIX
2453    interface uses malloc() for output vectors. See item 31 above.
2457    The output is an unsigned integer that contains the default limit of the number
2458    of match() calls in a pcre_exec() execution. See 42 above.
2460    44. pcretest has been upgraded by the addition of the -C option. This causes it
2461    to extract all the available output from the new pcre_config() function, and to
2462    output it. The program then exits immediately.
2464    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2465    order to support additional features. One way would have been to define
2466    pcre_exec2() (for example) with extra arguments, but this would not have been
2467    extensible, and would also have required all calls to the original function to
2468    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2469    is used for passing in "extra" data from pcre_study().
2471    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2472    contains the following fields:
2474      flags         a bitmap indicating which of the following fields are set
2475      study_data    opaque data from pcre_study()
2476      match_limit   a way of specifying a limit on match() calls for a specific
2477                      call to pcre_exec()
2478      callout_data  data for callouts (see 49 below)
2480    The flag bits are also defined in pcre.h, and are
2486    The pcre_study() function now returns one of these new pcre_extra blocks, with
2487    the actual study data pointed to by the study_data field, and the
2488    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2489    before. That is, this change is entirely upwards-compatible and requires no
2490    change to existing code.
2492    If you want to pass in additional data to pcre_exec(), you can either place it
2493    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2494    block.
2496    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2497    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2498    times with different match limits, until it finds the minimum value needed for
2499    pcre_exec() to complete. The value is then output. This can be instructive; for
2500    most simple matches the number is quite small, but for pathological cases it
2501    gets very large very quickly.
2503    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2504    returns the size of the data block pointed to by the study_data field in a
2505    pcre_extra block, that is, the value that was passed as the argument to
2506    pcre_malloc() when PCRE was getting memory in which to place the information
2507    created by pcre_study(). The fourth argument should point to a size_t variable.
2508    pcretest has been extended so that this information is shown after a successful
2509    pcre_study() call when information about the compiled regex is being displayed.
2511    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2512    because what follows is always an absolute path. (Later: it turns out that this
2513    is more than cosmetic for MinGW, because it doesn't like empty path
2514    components.)
2516    49. Some changes have been made to the callout feature (see 28 above):
2518    (i)  A callout function now has three choices for what it returns:
2520           0  =>  success, carry on matching
2521         > 0  =>  failure at this point, but backtrack if possible
2522         < 0  =>  serious error, return this value from pcre_exec()
2524         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2525         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2526         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2527         use by callout functions. It will never be used by PCRE itself.
2529    (ii) The pcre_extra structure (see 45 above) has a void * field called
2530         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2531         pcre_callout_block structure has a field of the same name. The contents of
2532         the field passed in the pcre_extra structure are passed to the callout
2533         function in the corresponding field in the callout block. This makes it
2534         easier to use the same callout-containing regex from multiple threads. For
2535         testing, the pcretest program has a new data escape
2537           \C*n        pass the number n (may be negative) as callout_data
2539         If the callout function in pcretest receives a non-zero value as
2540         callout_data, it returns that value.
2542    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2543    there were some redundant $(CFLAGS) in commands that are now specified as
2544    $(LINK), which already includes $(CFLAGS).
2546    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2547    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2548    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2549    one-byte characters throughout. Note that case-insensitive matching applies
2550    only to characters whose values are less than 256. PCRE doesn't support the
2551    notion of cases for higher-valued characters.
2553    (i)   A character class whose characters are all within 0-255 is handled as
2554          a bit map, and the map is inverted for negative classes. Previously, a
2555          character > 255 always failed to match such a class; however it should
2556          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2558    (ii)  A negated character class with a single character < 255 is coded as
2559          "not this character" (OP_NOT). This wasn't working properly when the test
2560          character was multibyte, either singly or repeated.
2562    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2563          mode, for example: \x{100}{2,3}.
2565    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2566          singly or repeated) now correctly test multibyte characters. However,
2567          PCRE doesn't recognize any characters with values greater than 255 as
2568          digits, spaces, or word characters. Such characters always match \D, \S,
2569          and \W, and never match \d, \s, or \w.
2571    (v)   Classes may now contain characters and character ranges with values
2572          greater than 255. For example: [ab\x{100}-\x{400}].
2574    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2575          PCRE in UTF-8 mode.
2577    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2578    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2579    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2580    value.)
2582    53. The single man page has become too large. I have therefore split it up into
2583    a number of separate man pages. These also give rise to individual HTML pages;
2584    these are now put in a separate directory, and there is an index.html page that
2585    lists them all. Some hyperlinking between the pages has been installed.
2587    54. Added convenience functions for handling named capturing parentheses.
2589    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2590    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2591    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2592    are faulted.
2594    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2595    calling configure. These values are used when compiling the dftables.c program
2596    which is run to generate the source of the default character tables. They
2597    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2598    you will need to set these values.
2600    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2603    Version 3.9 02-Jan-02
2604    ---------------------
2606    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2608    2. If --disable-static was given, the building process failed when trying to
2609    build pcretest and pcregrep. (For some reason it was using libtool to compile
2610    them, which is not right, as they aren't part of the library.)
2613    Version 3.8 18-Dec-01
2614    ---------------------
2616    1. The experimental UTF-8 code was completely screwed up. It was packing the
2617    bytes in the wrong order. How dumb can you get?
2620    Version 3.7 29-Oct-01
2621    ---------------------
2623    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2624    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2625    this didn't happen under Solaris 8, where I normally test things.
2627    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2628    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2629    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2630    this fix an hour or so after the initial 3.7 release.)
2633    Version 3.6 23-Oct-01
2634    ---------------------
2636    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2637    offsets passed as NULL with zero offset count.
2639    2. The config.guess and config.sub files had not been updated when I moved to
2640    the latest autoconf.
2643    Version 3.5 15-Aug-01
2644    ---------------------
2646    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2647    had been forgotten.
2649    2. By using declared but undefined structures, we can avoid using "void"
2650    definitions in pcre.h while keeping the internal definitions of the structures
2651    private.
2653    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2654    user point of view, this means that both static and shared libraries are built
2655    by default, but this can be individually controlled. More of the work of
2656    handling this static/shared cases is now inside libtool instead of PCRE's make
2657    file.
2659    4. The pcretest utility is now installed along with pcregrep because it is
2660    useful for users (to test regexs) and by doing this, it automatically gets
2661    relinked by libtool. The documentation has been turned into a man page, so
2662    there are now .1, .txt, and .html versions in /doc.
2664    5. Upgrades to pcregrep:
2665       (i)   Added long-form option names like gnu grep.
2666       (ii)  Added --help to list all options with an explanatory phrase.
2667       (iii) Added -r, --recursive to recurse into sub-directories.
2668       (iv)  Added -f, --file to read patterns from a file.
2670    6. pcre_exec() was referring to its "code" argument before testing that
2671    argument for NULL (and giving an error if it was NULL).
2673    7. Upgraded Makefile.in to allow for compiling in a different directory from
2674    the source directory.
2676    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2677    options bits, the pointer it was passed was to an int instead of to an unsigned
2678    long int. This mattered only on 64-bit systems.
2680    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2681    generated) instead of pcre.in, which it its source. Also made the same change
2682    in several of the .c files.
2684    10. A new release of gcc defines printf() as a macro, which broke pcretest
2685    because it had an ifdef in the middle of a string argument for printf(). Fixed
2686    by using separate calls to printf().
2688    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2689    script, to force use of CR or LF instead of \n in the source. On non-Unix
2690    systems, the value can be set in config.h.
2692    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2693    absolute limit. Changed the text of the error message to make this clear, and
2694    likewise updated the man page.
2696    13. The limit of 99 on the number of capturing subpatterns has been removed.
2697    The new limit is 65535, which I hope will not be a "real" limit.
2700    Version 3.4 22-Aug-00
2701    ---------------------
2703    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2705    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2708    Version 3.3 01-Aug-00
2709    ---------------------
2711    1. If an octal character was given, but the value was greater than \377, it
2712    was not getting masked to the least significant bits, as documented. This could
2713    lead to crashes in some systems.
2715    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2716    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2718    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2719    These just pass their arguments on to (pcre_free)(), but they are provided
2720    because some uses of PCRE bind it to non-C systems that can call its functions,
2721    but cannot call free() or pcre_free() directly.
2723    4. Add "make test" as a synonym for "make check". Corrected some comments in
2724    the Makefile.
2726    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2727    Makefile.
2729    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2730    command called pgrep for grepping around the active processes.
2732    7. Added the beginnings of support for UTF-8 character strings.
2734    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2735    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2736    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2737    out for the ar command.)
2740    Version 3.2 12-May-00
2741    ---------------------
2743    This is purely a bug fixing release.
2745    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2746    of ZA. This was just one example of several cases that could provoke this bug,
2747    which was introduced by change 9 of version 2.00. The code for breaking
2748    infinite loops after an iteration that matches an empty string was't working
2749    correctly.
2751    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2752    when matched against abbab (for example). After matching an empty string, it
2753    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2754    caused it to match further down the string than it should.
2756    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2757    was there because it doesn't seem to be needed, and it causes trouble on some
2758    systems, as it is not a Standard C header. It has been removed.
2760    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2761    were reported on the Macintosh. The changes were from
2763      while ((c = *(++ptr)) != 0 && c != '\n');
2764    to
2765      while ((c = *(++ptr)) != 0 && c != '\n') ;
2767    Totally extraordinary, but if that's what it takes...
2769    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2770    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2771    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2772    assumes the way PCRE uses memmove() (always moving upwards).
2774    6. PCRE is being used in one environment where strchr() is not available. There
2775    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2776    faster code anyway.
2779    Version 3.1 09-Feb-00
2780    ---------------------
2782    The only change in this release is the fixing of some bugs in Makefile.in for
2783    the "install" target:
2785    (1) It was failing to install pcreposix.h.
2787    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2790    Version 3.0 01-Feb-00
2791    ---------------------
2793    1. Add support for the /+ modifier to perltest (to output $` like it does in
2794    pcretest).
2796    2. Add support for the /g modifier to perltest.
2798    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2799    matches null strings.
2801    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2802    pattern. Perl treats empty patterns specially - it reuses the most recent
2803    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2804    effect.
2806    5. The POSIX interface was broken in that it was just handing over the POSIX
2807    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2808    required a bigger vector, with some working space on the end. This means that
2809    the POSIX wrapper now has to get and free some memory, and copy the results.
2811    6. Added some simple autoconf support, placing the test data and the
2812    documentation in separate directories, re-organizing some of the
2813    information files, and making it build pcre-config (a GNU standard). Also added
2814    libtool support for building PCRE as a shared library, which is now the
2815    default.
2817    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2818    09 are not valid octal constants. Single digits will be used for minor values
2819    less than 10.
2821    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2822    existing programs that set these in the POSIX interface can use PCRE without
2823    modification.
2825    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2826    return all that pcre_info() returns, plus additional data. The pcre_info()
2827    function is retained for compatibility, but is considered to be obsolete.
2829    10. Added experimental recursion feature (?R) to handle one common case that
2830    Perl 5.6 will be able to do with (?p{...}).
2832    11. Added support for POSIX character classes like [:alpha:], which Perl is
2833    adopting.
2836    Version 2.08 31-Aug-99
2837    ----------------------
2839    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2840    trying to match at the startoffset position, but instead was moving forward to
2841    the next newline as if a previous match had failed.
2843    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2844    and could get into a loop if a null string was matched other than at the start
2845    of the subject.
2847    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2848    be distinguished at compile time, and for completeness also added PCRE_DATE.
2850    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2851    in GnuWin32 environments.
2854    Version 2.07 29-Jul-99
2855    ----------------------
2857    1. The documentation is now supplied in plain text form and HTML as well as in
2858    the form of man page sources.
2860    2. C++ compilers don't like assigning (void *) values to other pointer types.
2861    In particular this affects malloc(). Although there is no problem in Standard
2862    C, I've put in casts to keep C++ compilers happy.
2864    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2865    should be (const char *).
2867    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2868    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2869    However, I haven't made this a standard facility. The documentation doesn't
2870    mention it, and the Makefile doesn't support it.
2872    5. The Makefile now contains an "install" target, with editable destinations at
2873    the top of the file. The pcretest program is not installed.
2875    6. pgrep -V now gives the PCRE version number and date.
2877    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2878    causing the entire string to be ignored, instead of just the last character.
2880    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2881    non-matching string, it can take a very, very long time, even for strings of
2882    quite modest length, because of the nested recursion. PCRE now does better in
2883    some of these cases. It does this by remembering the last required literal
2884    character in the pattern, and pre-searching the subject to ensure it is present
2885    before running the real match. In other words, it applies a heuristic to detect
2886    some types of certain failure quickly, and in the above example, if presented
2887    with a string that has no trailing " it gives "no match" very quickly.
2889    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2890    other alternatives are tried instead.
2893    Version 2.06 09-Jun-99
2894    ----------------------
2896    1. Change pcretest's output for amount of store used to show just the code
2897    space, because the remainder (the data block) varies in size between 32-bit and
2898    64-bit systems.
2900    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2901    start matching at. This allows lookbehinds to work when searching for multiple
2902    occurrences in a string.
2904    3. Added additional options to pcretest for testing multiple occurrences:
2906       /+   outputs the rest of the string that follows a match
2907       /g   loops for multiple occurrences, using the new startoffset argument
2908       /G   loops for multiple occurrences by passing an incremented pointer
2910    4. PCRE wasn't doing the "first character" optimization for patterns starting
2911    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2912    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2913    the letter 'x'. On long subject strings, this gives a significant speed-up.
2916    Version 2.05 21-Apr-99
2917    ----------------------
2919    1. Changed the type of magic_number from int to long int so that it works
2920    properly on 16-bit systems.
2922    2. Fixed a bug which caused patterns starting with .* not to work correctly
2923    when the subject string contained newline characters. PCRE was assuming
2924    anchoring for such patterns in all cases, which is not correct because .* will
2925    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2926    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2927    must be retried after every newline in the subject.
2930    Version 2.04 18-Feb-99
2931    ----------------------
2933    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2934    computation of the store needed to hold the pattern was incorrect (too large).
2935    If such patterns were nested a few deep, this could multiply and become a real
2936    problem.
2938    2. Added /M option to pcretest to show the memory requirement of a specific
2939    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2941    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2942    compiled in such a way that the backtracking after subsequent failure was
2943    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2944    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2947    Version 2.03 02-Feb-99
2948    ----------------------
2950    1. Fixed typo and small mistake in man page.
2952    2. Added 4th condition (GPL supersedes if conflict) and created separate
2953    LICENCE file containing the conditions.
2955    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2956    Perl, that is the internal \ allows the delimiter to be included in the
2957    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2958    the final delimiter, add \ to the end of the pattern (to test the error).
2960    4. Added the convenience functions for extracting substrings after a successful
2961    match. Updated pcretest to make it able to test these functions.
2964  Version 2.02 14-Jan-99  Version 2.02 14-Jan-99
2965  ----------------------  ----------------------

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