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revision 53 by nigel, Sat Feb 24 21:39:42 2007 UTC revision 342 by ph10, Sun Apr 20 17:10:13 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.7 05-Mar-08
5    ---------------------
7    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
8        a string to a long long, pretend we don't even have a long long." This is
9        done by checking for the strtoq, strtoll, and _strtoi64 functions.
11    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
12        pre-7.6 versions, which defined a global no_arg variable instead of putting
13        it in the RE class. (See also #8 below.)
15    3.  Remove a line of dead code, identified by coverity and reported by Nuno
16        Lopes.
18    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
20        (1) The include/exclude patterns were being applied to the whole pathnames
21            of files, instead of just to the final components.
23        (2) If there was more than one level of directory, the subdirectories were
24            skipped unless they satisfied the include/exclude conditions. This is
25            inconsistent with GNU grep (and could even be seen as contrary to the
26            pcregrep specification - which I improved to make it absolutely clear).
27            The action now is always to scan all levels of directory, and just
28            apply the include/exclude patterns to regular files.
30    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
31        --exclude_dir in the tests to avoid scanning .svn directories.
33    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
34        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
35        doesn't support NULs in patterns.
37    7.  Added some missing "const"s to declarations of static tables in
38        pcre_compile.c and pcre_dfa_exec.c.
40    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
41        caused by fix #2  above. (Subsequently also a second patch to fix the
42        first patch. And a third patch - this was a messy problem.)
44    9.  Applied Craig's patch to remove the use of push_back().
46    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
47        matching function regexec().
49    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
50        which, however, unlike Perl's \g{...}, are subroutine calls, not back
51        references. PCRE supports relative numbers with this syntax (I don't think
52        Oniguruma does).
54    12. Previously, a group with a zero repeat such as (...){0} was completely
55        omitted from the compiled regex. However, this means that if the group
56        was called as a subroutine from elsewhere in the pattern, things went wrong
57        (an internal error was given). Such groups are now left in the compiled
58        pattern, with a new opcode that causes them to be skipped at execution
59        time.
61    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
62        to the way PCRE behaves:
64        (a) A lone ] character is dis-allowed (Perl treats it as data).
66        (b) A back reference to an unmatched subpattern matches an empty string
67            (Perl fails the current match path).
69        (c) A data ] in a character class must be notated as \] because if the
70            first data character in a class is ], it defines an empty class. (In
71            Perl it is not possible to have an empty class.) The empty class []
72            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
73            The negative empty class [^] matches any one character, independently
74            of the DOTALL setting.
76    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
77        non-existent subpattern following a character class starting with ']' and
78        containing () gave an internal compiling error instead of "reference to
79        non-existent subpattern". Fortunately, when the pattern did exist, the
80        compiled code was correct. (When scanning forwards to check for the
81        existencd of the subpattern, it was treating the data ']' as terminating
82        the class, so got the count wrong. When actually compiling, the reference
83        was subsequently set up correctly.)
85    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
86        it was being rejected as not supported by pcre_dfa_exec(), even though
87        other assertions are supported. I have made pcre_dfa_exec() support
88        (*FAIL).
90    16. The implementation of 13c above involved the invention of a new opcode,
91        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
92        cannot be changed at match time, I realized I could make a small
93        improvement to matching performance by compiling OP_ALLANY instead of
94        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
95        on the OP_ANY path.
98    Version 7.6 28-Jan-08
99    ---------------------
101    1.  A character class containing a very large number of characters with
102        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
103        overflow.
105    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
106        HAVE_LONG_LONG is not defined.
108    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
109        bring them up to date and include new features. This patch includes:
111        - Fixed PH's badly added libz and libbz2 support.
112        - Fixed a problem with static linking.
113        - Added pcredemo. [But later removed - see 7 below.]
114        - Fixed dftables problem and added an option.
115        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
116            HAVE_LONG_LONG.
117        - Added readline support for pcretest.
118        - Added an listing of the option settings after cmake has run.
120    4.  A user submitted a patch to Makefile that makes it easy to create
121        "pcre.dll" under mingw when using Configure/Make. I added stuff to
122        Makefile.am that cause it to include this special target, without
123        affecting anything else. Note that the same mingw target plus all
124        the other distribution libraries and programs are now supported
125        when configuring with CMake (see 6 below) instead of with
126        Configure/Make.
128    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
129        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
130        exported in the Windows port". It has not yet been confirmed that the patch
131        solves the problem, but it does no harm.
133    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
134        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
135        with CMake, and also correct the comment about stack recursion.
137    7.  Remove the automatic building of pcredemo from the ./configure system and
138        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
139        of a program that users should build themselves after PCRE is installed, so
140        building it automatically is not really right. What is more, it gave
141        trouble in some build environments.
143    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
146    Version 7.5 10-Jan-08
147    ---------------------
149    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
150        values in parens when parsing an RE using the C++ wrapper."
152    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
153        Characters greater than 255 were excluded from the class instead of being
154        included.
156    3.  The same bug as (2) above applied to negated POSIX classes such as
157        [:^space:].
159    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
160        defined or documented. It seems to have been a typo for PCRE_STATIC, so
161        I have changed it.
163    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
164        first named subpattern) and a construct such as (?&a) would reference the
165        first named subpattern whose name started with "a" (in other words, the
166        length check was missing). Both these problems are fixed. "Subpattern name
167        expected" is now given for (?&) (a zero-length name), and this patch also
168        makes it give the same error for \k'' (previously it complained that that
169        was a reference to a non-existent subpattern).
171    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
172        this is right because (?- can be followed by option settings as well as by
173        digits. I have, however, made the messages clearer.
175    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
176        than the number used in the conditional) now cause a compile-time error.
177        This is actually not compatible with Perl, which accepts such patterns, but
178        treats the conditional as always being FALSE (as PCRE used to), but it
179        seems to me that giving a diagnostic is better.
181    8.  Change "alphameric" to the more common word "alphanumeric" in comments
182        and messages.
184    9.  Fix two occurrences of "backslash" in comments that should have been
185        "backspace".
187    10. Remove two redundant lines of code that can never be obeyed (their function
188        was moved elsewhere).
190    11. The program that makes PCRE's Unicode character property table had a bug
191        which caused it to generate incorrect table entries for sequences of
192        characters that have the same character type, but are in different scripts.
193        It amalgamated them into a single range, with the script of the first of
194        them. In other words, some characters were in the wrong script. There were
195        thirteen such cases, affecting characters in the following ranges:
197          U+002b0 - U+002c1
198          U+0060c - U+0060d
199          U+0061e - U+00612
200          U+0064b - U+0065e
201          U+0074d - U+0076d
202          U+01800 - U+01805
203          U+01d00 - U+01d77
204          U+01d9b - U+01dbf
205          U+0200b - U+0200f
206          U+030fc - U+030fe
207          U+03260 - U+0327f
208          U+0fb46 - U+0fbb1
209          U+10450 - U+1049d
211    12. The -o option (show only the matching part of a line) for pcregrep was not
212        compatible with GNU grep in that, if there was more than one match in a
213        line, it showed only the first of them. It now behaves in the same way as
214        GNU grep.
216    13. If the -o and -v options were combined for pcregrep, it printed a blank
217        line for every non-matching line. GNU grep prints nothing, and pcregrep now
218        does the same. The return code can be used to tell if there were any
219        non-matching lines.
221    14. Added --file-offsets and --line-offsets to pcregrep.
223    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
224        infinitely looping recursion. The bug was that positive lookaheads were not
225        being skipped when checking for a possible empty match (negative lookaheads
226        and both kinds of lookbehind were skipped).
228    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
229        inclusion of <windows.h> to before rather than after the definition of
230        INVALID_FILE_ATTRIBUTES (patch from David Byron).
232    17. Specifying a possessive quantifier with a specific limit for a Unicode
233        character property caused pcre_compile() to compile bad code, which led at
234        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
235        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
236        caused the error; without that there was no problem.
238    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
240    19. Added --enable-pcretest-libreadline.
242    20. In pcrecpp.cc, the variable 'count' was incremented twice in
243        RE::GlobalReplace(). As a result, the number of replacements returned was
244        double what it should be. I removed one of the increments, but Craig sent a
245        later patch that removed the other one (the right fix) and added unit tests
246        that check the return values (which was not done before).
248    21. Several CMake things:
250        (1) Arranged that, when cmake is used on Unix, the libraries end up with
251            the names libpcre and libpcreposix, not just pcre and pcreposix.
253        (2) The above change means that pcretest and pcregrep are now correctly
254            linked with the newly-built libraries, not previously installed ones.
258    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
259        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
260        UTF-8 newline character). The key issue is that the pattern starts .*;
261        this means that the match must be either at the beginning, or after a
262        newline. The bug was in the code for advancing after a failed match and
263        checking that the new position followed a newline. It was not taking
264        account of UTF-8 characters correctly.
266    23. PCRE was behaving differently from Perl in the way it recognized POSIX
267        character classes. PCRE was not treating the sequence [:...:] as a
268        character class unless the ... were all letters. Perl, however, seems to
269        allow any characters between [: and :], though of course it rejects as
270        unknown any "names" that contain non-letters, because all the known class
271        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
272        for example, whereas PCRE did not - it did not recognize a POSIX character
273        class. This seemed a bit dangerous, so the code has been changed to be
274        closer to Perl. The behaviour is not identical to Perl, because PCRE will
275        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
276        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
277        Perl does, and where it didn't before.
279    24. Rewrite so as to remove the single use of %n from pcregrep because in some
280        Windows environments %n is disabled by default.
283    Version 7.4 21-Sep-07
284    ---------------------
286    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
287        means that a class such as [\s] counted as "explicit reference to CR or
288        LF". That isn't really right - the whole point of the change was to try to
289        help when there was an actual mention of one of the two characters. So now
290        the change happens only if \r or \n (or a literal CR or LF) character is
291        encountered.
293    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
294        of both had grown to the point where there were only 3 bits left.
295        Fortunately, there was spare space in the data structure, and so I have
296        moved the internal flags into a new 16-bit field to free up more option
297        bits.
299    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
300        but did not set the internal JCHANGED flag - either of these is enough to
301        control the way the "get" function works - but the PCRE_INFO_JCHANGED
302        facility is supposed to tell if (?J) was ever used, so now (?J) at the
303        start sets both bits.
305    4.  Added options (at build time, compile time, exec time) to change \R from
306        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
308    5.  doc/pcresyntax.html was missing from the distribution.
310    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
311        compatibility, even though it is no longer used.
313    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
314        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
315        windows.h file is present (where different names are used). [This was
316        reversed later after testing - see 16 below.]
318    8.  Changed all #include <config.h> to #include "config.h". There were also
319        some further <pcre.h> cases that I changed to "pcre.h".
321    9.  When pcregrep was used with the --colour option, it missed the line ending
322        sequence off the lines that it output.
324    10. It was pointed out to me that arrays of string pointers cause lots of
325        relocations when a shared library is dynamically loaded. A technique of
326        using a single long string with a table of offsets can drastically reduce
327        these. I have refactored PCRE in four places to do this. The result is
328        dramatic:
330          Originally:                          290
331          After changing UCP table:            187
332          After changing error message table:   43
333          After changing table of "verbs"       36
334          After changing table of Posix names   22
336        Thanks to the folks working on Gregex for glib for this insight.
338    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
339        unicode-properties was also set.
341    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
343    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
344        checked only for CRLF.
346    14. Added casts to pcretest.c to avoid compiler warnings.
348    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
350    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
351        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
352        entirely. This removes changes made in 7 above.
354    17. The CMake files have been updated, and there is now more information about
355        building with CMake in the NON-UNIX-USE document.
358    Version 7.3 28-Aug-07
359    ---------------------
361     1. In the rejigging of the build system that eventually resulted in 7.1, the
362        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
363        brackets there is not right, since it causes compilers to look for an
364        installed pcre.h, not the version that is in the source that is being
365        compiled (which of course may be different). I have changed it back to:
367          #include "pcre.h"
369        I have a vague recollection that the change was concerned with compiling in
370        different directories, but in the new build system, that is taken care of
371        by the VPATH setting the Makefile.
373     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
374        when the subject happened to end in the byte 0x85 (e.g. if the last
375        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
376        characters but of course it shouldn't be taken as a newline when it is part
377        of another character. The bug was that, for an unlimited repeat of . in
378        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
379        characters when looking for a newline.
381     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
383     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
384        in debug output.
386     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
387        long printing in the pcrecpp unittest when running under MinGW.
389     6. ESC_K was left out of the EBCDIC table.
391     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
392        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
393        limit also applies to "virtual nesting" when a pattern is recursive, and in
394        this case 1000 isn't so big. I have been able to remove this limit at the
395        expense of backing off one optimization in certain circumstances. Normally,
396        when pcre_exec() would call its internal match() function recursively and
397        immediately return the result unconditionally, it uses a "tail recursion"
398        feature to save stack. However, when a subpattern that can match an empty
399        string has an unlimited repetition quantifier, it no longer makes this
400        optimization. That gives it a stack frame in which to save the data for
401        checking that an empty string has been matched. Previously this was taken
402        from the 1000-entry workspace that had been reserved. So now there is no
403        explicit limit, but more stack is used.
405     8. Applied Daniel's patches to solve problems with the import/export magic
406        syntax that is required for Windows, and which was going wrong for the
407        pcreposix and pcrecpp parts of the library. These were overlooked when this
408        problem was solved for the main library.
410     9. There were some crude static tests to avoid integer overflow when computing
411        the size of patterns that contain repeated groups with explicit upper
412        limits. As the maximum quantifier is 65535, the maximum group length was
413        set at 30,000 so that the product of these two numbers did not overflow a
414        32-bit integer. However, it turns out that people want to use groups that
415        are longer than 30,000 bytes (though not repeat them that many times).
416        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
417        made it possible to implement the integer overflow checks in a much more
418        dynamic way, which I have now done. The artificial limitation on group
419        length has been removed - we now have only the limit on the total length of
420        the compiled pattern, which depends on the LINK_SIZE setting.
422    10. Fixed a bug in the documentation for get/copy named substring when
423        duplicate names are permitted. If none of the named substrings are set, the
424        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
425        empty string.
427    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
428        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
429        because the ] is interpreted as the first data character and the
430        terminating ] is not found. PCRE has been made compatible with Perl in this
431        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
432        cause memory overwriting.
434    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
435        string has been matched (to stop an infinite loop). It was not recognizing
436        a conditional subpattern that could match an empty string if that
437        subpattern was within another subpattern. For example, it looped when
438        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
439        condition was not nested. This bug has been fixed.
441    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
442        past the start of the subject in the presence of bytes with the top bit
443        set, for example "\x8aBCD".
445    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
446        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
448    14. Optimized (?!) to (*FAIL).
450    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
451        This restricts code points to be within the range 0 to 0x10FFFF, excluding
452        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
453        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
454        does: it's just the validity check that is more restrictive.
456    16. Inserted checks for integer overflows during escape sequence (backslash)
457        processing, and also fixed erroneous offset values for syntax errors during
458        backslash processing.
460    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
461        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
463    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
464        caused an overrun.
466    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
467        something other than just ASCII characters) inside a group that had an
468        unlimited repeat caused a loop at compile time (while checking to see
469        whether the group could match an empty string).
471    20. Debugging a pattern containing \p or \P could cause a crash. For example,
472        [\P{Any}] did so. (Error in the code for printing property names.)
474    21. An orphan \E inside a character class could cause a crash.
476    22. A repeated capturing bracket such as (A)? could cause a wild memory
477        reference during compilation.
479    23. There are several functions in pcre_compile() that scan along a compiled
480        expression for various reasons (e.g. to see if it's fixed length for look
481        behind). There were bugs in these functions when a repeated \p or \P was
482        present in the pattern. These operators have additional parameters compared
483        with \d, etc, and these were not being taken into account when moving along
484        the compiled data. Specifically:
486        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
487            length.
489        (b) An item such as \pL+ within a repeated group could cause crashes or
490            loops.
492        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
493            "reference to non-existent subpattern" error.
495        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
497    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
498        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
500    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
502    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
503        character were causing crashes (broken optimization).
505    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
506        \p or \P) caused a compile-time loop.
508    28. More problems have arisen in unanchored patterns when CRLF is a valid line
509        break. For example, the unstudied pattern [\r\n]A does not match the string
510        "\r\nA" because change 7.0/46 below moves the current point on by two
511        characters after failing to match at the start. However, the pattern \nA
512        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
513        the same is true. There doesn't seem any very clean way out of this, but
514        what I have chosen to do makes the common cases work: PCRE now takes note
515        of whether there can be an explicit match for \r or \n anywhere in the
516        pattern, and if so, 7.0/46 no longer applies. As part of this change,
517        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
518        pattern has explicit CR or LF references.
520    29. Added (*CR) etc for changing newline setting at start of pattern.
523    Version 7.2 19-Jun-07
524    ---------------------
526     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
527        which is apparently normally available under Windows.
529     2. Re-jig the pcregrep tests with different newline settings in an attempt
530        to make them independent of the local environment's newline setting.
532     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
534     4. Some of the "internals" tests were previously cut out when the link size
535        was not 2, because the output contained actual offsets. The recent new
536        "Z" feature of pcretest means that these can be cut out, making the tests
537        usable with all link sizes.
539     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
540        stack recursion. This gives a massive performance boost under BSD, but just
541        a small improvement under Linux. However, it saves one field in the frame
542        in all cases.
544     6. Added more features from the forthcoming Perl 5.10:
546        (a) (?-n) (where n is a string of digits) is a relative subroutine or
547            recursion call. It refers to the nth most recently opened parentheses.
549        (b) (?+n) is also a relative subroutine call; it refers to the nth next
550            to be opened parentheses.
552        (c) Conditions that refer to capturing parentheses can be specified
553            relatively, for example, (?(-2)... or (?(+3)...
555        (d) \K resets the start of the current match so that everything before
556            is not part of it.
558        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
560        (f) \g{name} is another synonym - part of Perl 5.10's unification of
561            reference syntax.
563        (g) (?| introduces a group in which the numbering of parentheses in each
564            alternative starts with the same number.
566        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
568     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
571     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
572        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
573        for detecting groups that can match an empty string.
575     9. A pattern with a very large number of alternatives (more than several
576        hundred) was running out of internal workspace during the pre-compile
577        phase, where pcre_compile() figures out how much memory will be needed. A
578        bit of new cunning has reduced the workspace needed for groups with
579        alternatives. The 1000-alternative test pattern now uses 12 bytes of
580        workspace instead of running out of the 4096 that are available.
582    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
584    11. Applied patch from Google to remove an optimization that didn't quite work.
585        The report of the bug said:
587          pcrecpp::RE("a*").FullMatch("aaa") matches, while
588          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
589          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
591    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
592        it matched the wrong number of bytes.
595    Version 7.1 24-Apr-07
596    ---------------------
598     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
599        that is more "standard", making use of automake and other Autotools. There
600        is some re-arrangement of the files and adjustment of comments consequent
601        on this.
603     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
604        for recursive directory scanning broke on some systems because the files
605        are not scanned in any specific order and on different systems the order
606        was different. A call to "sort" has been inserted into RunGrepTest for the
607        approprate test as a short-term fix. In the longer term there may be an
608        alternative.
610     3. I had an email from Eric Raymond about problems translating some of PCRE's
611        man pages to HTML (despite the fact that I distribute HTML pages, some
612        people do their own conversions for various reasons). The problems
613        concerned the use of low-level troff macros .br and .in. I have therefore
614        removed all such uses from the man pages (some were redundant, some could
615        be replaced by .nf/.fi pairs). The 132html script that I use to generate
616        HTML has been updated to handle .nf/.fi and to complain if it encounters
617        .br or .in.
619     4. Updated comments in configure.ac that get placed in config.h.in and also
620        arranged for config.h to be included in the distribution, with the name
621        config.h.generic, for the benefit of those who have to compile without
622        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
624     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
625        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
626        makevp.bat for the current PCRE, using the additional files
627        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
629     6. A Windows user reported a minor discrepancy with test 2, which turned out
630        to be caused by a trailing space on an input line that had got lost in his
631        copy. The trailing space was an accident, so I've just removed it.
633     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
634        that is needed.
636     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
637        as "const" (a) because they are and (b) because it helps the PHP
638        maintainers who have recently made a script to detect big data structures
639        in the php code that should be moved to the .rodata section. I remembered
640        to update Builducptable as well, so it won't revert if ucptable.h is ever
641        re-created.
643     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
644        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
645        order to be able to cut out the UTF-8 tables in the latter when UTF-8
646        support is not required. This saves 1.5-2K of code, which is important in
647        some applications.
649        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
650        so as not to refer to the tables, even though these functions will never be
651        called when UTF-8 support is disabled. Otherwise there are problems with a
652        shared library.
654    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
656        (a) It was defining its arguments as char * instead of void *.
658        (b) It was assuming that all moves were upwards in memory; this was true
659            a long time ago when I wrote it, but is no longer the case.
661        The emulated memove() is provided for those environments that have neither
662        memmove() nor bcopy(). I didn't think anyone used it these days, but that
663        is clearly not the case, as these two bugs were recently reported.
665    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
666        and Detrail to create the HTML documentation, the .txt form of the man
667        pages, and it removes trailing spaces from listed files. It also creates
668        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
669        case, it wraps all the #defines with #ifndefs. This script should be run
670        before "make dist".
672    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
673        with Unicode property support.
675        (a) For a maximizing quantifier, if the two different cases of the
676            character were of different lengths in their UTF-8 codings (there are
677            some cases like this - I found 11), and the matching function had to
678            back up over a mixture of the two cases, it incorrectly assumed they
679            were both the same length.
681        (b) When PCRE was configured to use the heap rather than the stack for
682            recursion during matching, it was not correctly preserving the data for
683            the other case of a UTF-8 character when checking ahead for a match
684            while processing a minimizing repeat. If the check also involved
685            matching a wide character, but failed, corruption could cause an
686            erroneous result when trying to check for a repeat of the original
687            character.
689    13. Some tidying changes to the testing mechanism:
691        (a) The RunTest script now detects the internal link size and whether there
692            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
693            values substituted by "configure". (The RunGrepTest script already did
694            this for UTF-8.) The configure.ac script no longer substitutes the
695            relevant variables.
697        (b) The debugging options /B and /D in pcretest show the compiled bytecode
698            with length and offset values. This means that the output is different
699            for different internal link sizes. Test 2 is skipped for link sizes
700            other than 2 because of this, bypassing the problem. Unfortunately,
701            there was also a test in test 3 (the locale tests) that used /B and
702            failed for link sizes other than 2. Rather than cut the whole test out,
703            I have added a new /Z option to pcretest that replaces the length and
704            offset values with spaces. This is now used to make test 3 independent
705            of link size. (Test 2 will be tidied up later.)
707    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
708        segmentation fault instead of returning the appropriate error message.
710    15. In multiline mode when the newline sequence was set to "any", the pattern
711        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
712        This doesn't seem right; it now treats the CRLF combination as the line
713        ending, and so does not match in that case. It's only a pattern such as ^$
714        that would hit this one: something like ^ABC$ would have failed after \r
715        and then tried again after \r\n.
717    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
718        in an attempt to make files that differ only in their line terminators
719        compare equal. This works on Linux.
721    17. Under certain error circumstances pcregrep might try to free random memory
722        as it exited. This is now fixed, thanks to valgrind.
724    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
725        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
726        was because its rules for how to advance for /g after matching an empty
727        string at the end of a line did not allow for this case. They now check for
728        it specially.
730    20. pcretest is supposed to handle patterns and data of any length, by
731        extending its buffers when necessary. It was getting this wrong when the
732        buffer for a data line had to be extended.
734    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
735        CRLF as a newline sequence.
737    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
738        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
739        I have nevertheless tidied it up.
741    23. Added some casts to kill warnings from HP-UX ia64 compiler.
743    24. Added a man page for pcre-config.
746    Version 7.0 19-Dec-06
747    ---------------------
749     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
750        moving to gcc 4.1.1.
752     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
753        sys/time.h, which is documented as needed for this function. It doesn't
754        seem to matter on Linux, but it showed up on some releases of OS X.
756     3. It seems that there are systems where bytes whose values are greater than
757        127 match isprint() in the "C" locale. The "C" locale should be the
758        default when a C program starts up. In most systems, only ASCII printing
759        characters match isprint(). This difference caused the output from pcretest
760        to vary, making some of the tests fail. I have changed pcretest so that:
762        (a) When it is outputting text in the compiled version of a pattern, bytes
763            other than 32-126 are always shown as hex escapes.
765        (b) When it is outputting text that is a matched part of a subject string,
766            it does the same, unless a different locale has been set for the match
767            (using the /L modifier). In this case, it uses isprint() to decide.
769     4. Fixed a major bug that caused incorrect computation of the amount of memory
770        required for a compiled pattern when options that changed within the
771        pattern affected the logic of the preliminary scan that determines the
772        length. The relevant options are -x, and -i in UTF-8 mode. The result was
773        that the computed length was too small. The symptoms of this bug were
774        either the PCRE error "internal error: code overflow" from pcre_compile(),
775        or a glibc crash with a message such as "pcretest: free(): invalid next
776        size (fast)". Examples of patterns that provoked this bug (shown in
777        pcretest format) are:
779          /(?-x: )/x
780          /(?x)(?-x: \s*#\s*)/
781          /((?i)[\x{c0}])/8
782          /(?i:[\x{c0}])/8
784        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
785        is now done differently.
787     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
788        wrapper classes; (b) implement a new function in the C++ scanner that is
789        more efficient than the old way of doing things because it avoids levels of
790        recursion in the regex matching; (c) add a paragraph to the documentation
791        for the FullMatch() function.
793     6. The escape sequence \n was being treated as whatever was defined as
794        "newline". Not only was this contrary to the documentation, which states
795        that \n is character 10 (hex 0A), but it also went horribly wrong when
796        "newline" was defined as CRLF. This has been fixed.
798     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
799        was being set to -1 for the "end of line" case (supposedly a value that no
800        character can have). Though this value is never used (the check for end of
801        line is "zero bytes in current character"), it caused compiler complaints.
802        I've changed it to 0xffffffff.
804     8. In pcre_version.c, the version string was being built by a sequence of
805        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
806        string (as it is for production releases) called a macro with an empty
807        argument. The C standard says the result of this is undefined. The gcc
808        compiler treats it as an empty string (which was what was wanted) but it is
809        reported that Visual C gives an error. The source has been hacked around to
810        avoid this problem.
812     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
813        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
814        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
815        of them did).
817    10. Originally, pcretest opened its input and output without "b"; then I was
818        told that "b" was needed in some environments, so it was added for release
819        5.0 to both the input and output. (It makes no difference on Unix-like
820        systems.) Later I was told that it is wrong for the input on Windows. I've
821        now abstracted the modes into two macros, to make it easier to fiddle with
822        them, and removed "b" from the input mode under Windows.
824    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
826    12. Added -help and --help to pcretest as an official way of being reminded
827        of the options.
829    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
830        and pcrecpp.cc because they annoy compilers at high warning levels.
832    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
834    15. Fixed an occurrence of == in configure.ac that should have been = (shell
835        scripts are not C programs :-) and which was not noticed because it works
836        on Linux.
838    16. pcretest is supposed to handle any length of pattern and data line (as one
839        line or as a continued sequence of lines) by extending its input buffer if
840        necessary. This feature was broken for very long pattern lines, leading to
841        a string of junk being passed to pcre_compile() if the pattern was longer
842        than about 50K.
844    17. I have done a major re-factoring of the way pcre_compile() computes the
845        amount of memory needed for a compiled pattern. Previously, there was code
846        that made a preliminary scan of the pattern in order to do this. That was
847        OK when PCRE was new, but as the facilities have expanded, it has become
848        harder and harder to keep it in step with the real compile phase, and there
849        have been a number of bugs (see for example, 4 above). I have now found a
850        cunning way of running the real compile function in a "fake" mode that
851        enables it to compute how much memory it would need, while actually only
852        ever using a few hundred bytes of working memory and without too many
853        tests of the mode. This should make future maintenance and development
854        easier. A side effect of this work is that the limit of 200 on the nesting
855        depth of parentheses has been removed (though this was never a serious
856        limitation, I suspect). However, there is a downside: pcre_compile() now
857        runs more slowly than before (30% or more, depending on the pattern). I
858        hope this isn't a big issue. There is no effect on runtime performance.
860    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
861        newline (only possible for the last line of a file) and it was a
862        pattern that set a locale (followed by /Lsomething), pcretest crashed.
864    19. Added additional timing features to pcretest. (1) The -tm option now times
865        matching only, not compiling. (2) Both -t and -tm can be followed, as a
866        separate command line item, by a number that specifies the number of
867        repeats to use when timing. The default is 50000; this gives better
868        precision, but takes uncomfortably long for very large patterns.
870    20. Extended pcre_study() to be more clever in cases where a branch of a
871        subpattern has no definite first character. For example, (a*|b*)[cd] would
872        previously give no result from pcre_study(). Now it recognizes that the
873        first character must be a, b, c, or d.
875    21. There was an incorrect error "recursive call could loop indefinitely" if
876        a subpattern (or the entire pattern) that was being tested for matching an
877        empty string contained only one non-empty item after a nested subpattern.
878        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
879        incorrectly, because the \d was being skipped in the check.
881    22. The pcretest program now has a new pattern option /B and a command line
882        option -b, which is equivalent to adding /B to every pattern. This causes
883        it to show the compiled bytecode, without the additional information that
884        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
885        is the same as /B/I).
887    23. A new optimization is now able automatically to treat some sequences such
888        as a*b as a*+b. More specifically, if something simple (such as a character
889        or a simple class like \d) has an unlimited quantifier, and is followed by
890        something that cannot possibly match the quantified thing, the quantifier
891        is automatically "possessified".
893    24. A recursive reference to a subpattern whose number was greater than 39
894        went wrong under certain circumstances in UTF-8 mode. This bug could also
895        have affected the operation of pcre_study().
897    25. Realized that a little bit of performance could be had by replacing
898        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
900    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
902    27. Possessive quantifiers such as a++ were previously implemented by turning
903        them into atomic groups such as ($>a+). Now they have their own opcodes,
904        which improves performance. This includes the automatically created ones
905        from 23 above.
907    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
908        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
909        the first matched character to be a colon. This applied both to named and
910        numbered groups.
912    29. The ucpinternal.h header file was missing its idempotency #ifdef.
914    30. I was sent a "project" file called libpcre.a.dev which I understand makes
915        building PCRE on Windows easier, so I have included it in the distribution.
917    31. There is now a check in pcretest against a ridiculously large number being
918        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
919        loop, the loop is abandoned.
921    32. Forward references to subpatterns in conditions such as (?(2)...) where
922        subpattern 2 is defined later cause pcre_compile() to search forwards in
923        the pattern for the relevant set of parentheses. This search went wrong
924        when there were unescaped parentheses in a character class, parentheses
925        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
927    33. "Subroutine" calls and backreferences were previously restricted to
928        referencing subpatterns earlier in the regex. This restriction has now
929        been removed.
931    34. Added a number of extra features that are going to be in Perl 5.10. On the
932        whole, these are just syntactic alternatives for features that PCRE had
933        previously implemented using the Python syntax or my own invention. The
934        other formats are all retained for compatibility.
936        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
937            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
938            also .NET compatible.
940        (b) A recursion or subroutine call to a named group can now be defined as
941            (?&name) as well as (?P>name).
943        (c) A backreference to a named group can now be defined as \k<name> or
944            \k'name' as well as (?P=name). The new forms, as well as being in Perl
945            5.10, are also .NET compatible.
947        (d) A conditional reference to a named group can now use the syntax
948            (?(<name>) or (?('name') as well as (?(name).
950        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
951            groups (named and numbered) that are never evaluated inline, but can be
952            called as "subroutines" from elsewhere. In effect, the DEFINE condition
953            is always false. There may be only one alternative in such a group.
955        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
956            as the simple (?(R). The condition is true only if the most recent
957            recursion is that of the given number or name. It does not search out
958            through the entire recursion stack.
960        (g) The escape \gN or \g{N} has been added, where N is a positive or
961            negative number, specifying an absolute or relative reference.
963    35. Tidied to get rid of some further signed/unsigned compiler warnings and
964        some "unreachable code" warnings.
966    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
967        things, this adds five new scripts.
969    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
970        There were also incompatibilities regarding the handling of \Q..\E inside
971        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
972        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
974    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
975        matches an empty string, and forcibly breaks the loop. There were bugs in
976        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
977        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
978        separate and independent bugs (that affected different cases) have been
979        fixed.
981    39. Refactored the code to abolish the use of different opcodes for small
982        capturing bracket numbers. This is a tidy that I avoided doing when I
983        removed the limit on the number of capturing brackets for 3.5 back in 2001.
984        The new approach is not only tidier, it makes it possible to reduce the
985        memory needed to fix the previous bug (38).
987    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
988        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
989        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
990        mode.
992    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
993        report.
995    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
996        copy construction and assignment in the C++ wrapper.
998    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
999        couple of bugs that could have given wrong results in the "--newline=crlf"
1000        case.
1002    44. Added a number of casts and did some reorganization of signed/unsigned int
1003        variables following suggestions from Dair Grant. Also renamed the variable
1004        "this" as "item" because it is a C++ keyword.
1006    45. Arranged for dftables to add
1008          #include "pcre_internal.h"
1010        to pcre_chartables.c because without it, gcc 4.x may remove the array
1011        definition from the final binary if PCRE is built into a static library and
1012        dead code stripping is activated.
1014    46. For an unanchored pattern, if a match attempt fails at the start of a
1015        newline sequence, and the newline setting is CRLF or ANY, and the next two
1016        characters are CRLF, advance by two characters instead of one.
1019    Version 6.7 04-Jul-06
1020    ---------------------
1022     1. In order to handle tests when input lines are enormously long, pcretest has
1023        been re-factored so that it automatically extends its buffers when
1024        necessary. The code is crude, but this _is_ just a test program. The
1025        default size has been increased from 32K to 50K.
1027     2. The code in pcre_study() was using the value of the re argument before
1028        testing it for NULL. (Of course, in any sensible call of the function, it
1029        won't be NULL.)
1031     3. The memmove() emulation function in pcre_internal.h, which is used on
1032        systems that lack both memmove() and bcopy() - that is, hardly ever -
1033        was missing a "static" storage class specifier.
1035     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1036        containing an extended class (one that cannot be represented by a bitmap
1037        because it contains high-valued characters or Unicode property items, e.g.
1038        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1039        pattern, but PCRE should not loop if you do not (it no longer does).
1040        [Detail: two cases were found: (a) a repeated subpattern containing an
1041        extended class; (b) a recursive reference to a subpattern that followed a
1042        previous extended class. It wasn't skipping over the extended class
1043        correctly when UTF-8 mode was not set.]
1045     5. A negated single-character class was not being recognized as fixed-length
1046        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1047        compile error "lookbehind assertion is not fixed length".
1049     6. The RunPerlTest auxiliary script was showing an unexpected difference
1050        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1051        write a Perl script that can interpret lines of an input file either as
1052        byte characters or as UTF-8, which is what "perltest" was being required to
1053        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1054        can't do is switch easily at run time between having the "use utf8;" pragma
1055        or not. In the end, I fudged it by using the RunPerlTest script to insert
1056        "use utf8;" explicitly for the UTF-8 tests.
1058     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1059        the end of the subject string, contrary to the documentation and to what
1060        Perl does. This was true of both matching functions. Now it matches only at
1061        the start of the subject and immediately after *internal* newlines.
1063     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1064        a pointer to an int instead of a pointer to an unsigned long int. This
1065        caused problems on 64-bit systems.
1067     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1068        instance of the 'standard' template library not being so standard".
1070    10. There was no check on the number of named subpatterns nor the maximum
1071        length of a subpattern name. The product of these values is used to compute
1072        the size of the memory block for a compiled pattern. By supplying a very
1073        long subpattern name and a large number of named subpatterns, the size
1074        computation could be caused to overflow. This is now prevented by limiting
1075        the length of names to 32 characters, and the number of named subpatterns
1076        to 10,000.
1078    11. Subpatterns that are repeated with specific counts have to be replicated in
1079        the compiled pattern. The size of memory for this was computed from the
1080        length of the subpattern and the repeat count. The latter is limited to
1081        65535, but there was no limit on the former, meaning that integer overflow
1082        could in principle occur. The compiled length of a repeated subpattern is
1083        now limited to 30,000 bytes in order to prevent this.
1085    12. Added the optional facility to have named substrings with the same name.
1087    13. Added the ability to use a named substring as a condition, using the
1088        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1089        are numbers (not recommended). Forward references are permitted.
1091    14. Added forward references in named backreferences (if you see what I mean).
1093    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1094        pattern could run off the end of the subject. For example, the pattern
1095        "(?s)(.{1,5})"8 did this with the subject "ab".
1097    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1098        PCRE_CASELESS was set when matching characters that were quantified with ?
1099        or *.
1101    17. A character class other than a single negated character that had a minimum
1102        but no maximum quantifier - for example [ab]{6,} - was not handled
1103        correctly by pce_dfa_exec(). It would match only one character.
1105    18. A valid (though odd) pattern that looked like a POSIX character
1106        class but used an invalid character after [ (for example [[,abc,]]) caused
1107        pcre_compile() to give the error "Failed: internal error: code overflow" or
1108        in some cases to crash with a glibc free() error. This could even happen if
1109        the pattern terminated after [[ but there just happened to be a sequence of
1110        letters, a binary zero, and a closing ] in the memory that followed.
1112    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1113        over the years. Originally (before any Unicode support), just the bottom 8
1114        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1115        output from "man perlunicode" includes this:
1117          The regular expression compiler produces polymorphic opcodes.  That
1118          is, the pattern adapts to the data and automatically switches to
1119          the Unicode character scheme when presented with Unicode data--or
1120          instead uses a traditional byte scheme when presented with byte
1121          data.
1123        Sadly, a wide octal escape does not cause a switch, and in a string with
1124        no other multibyte characters, these octal escapes are treated as before.
1125        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1126        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1127        Unicode string.
1129        I have not perpetrated such confusion in PCRE. Up till now, it took just
1130        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1131        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1132        translate to the appropriate multibyte character.
1134    29. Applied some refactoring to reduce the number of warnings from Microsoft
1135        and Borland compilers. This has included removing the fudge introduced
1136        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1137        a warning about an unused variable.
1139    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1140        characters since release 4.0, because Perl (from release 5.004) does not.
1141        [Or at least, is documented not to: some releases seem to be in conflict
1142        with the documentation.] However, when a pattern was studied with
1143        pcre_study() and all its branches started with \s, PCRE still included VT
1144        as a possible starting character. Of course, this did no harm; it just
1145        caused an unnecessary match attempt.
1147    22. Removed a now-redundant internal flag bit that recorded the fact that case
1148        dependency changed within the pattern. This was once needed for "required
1149        byte" processing, but is no longer used. This recovers a now-scarce options
1150        bit. Also moved the least significant internal flag bit to the most-
1151        significant bit of the word, which was not previously used (hangover from
1152        the days when it was an int rather than a uint) to free up another bit for
1153        the future.
1155    23. Added support for CRLF line endings as well as CR and LF. As well as the
1156        default being selectable at build time, it can now be changed at runtime
1157        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1158        specify that it is scanning data with non-default line endings.
1160    24. Changed the definition of CXXLINK to make it agree with the definition of
1161        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1163    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1164        recursions. This makes a big different to stack usage for some patterns.
1166    26. If a subpattern containing a named recursion or subroutine reference such
1167        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1168        the space required for the compiled pattern went wrong and gave too small a
1169        value. Depending on the environment, this could lead to "Failed: internal
1170        error: code overflow at offset 49" or "glibc detected double free or
1171        corruption" errors.
1173    27. Applied patches from Google (a) to support the new newline modes and (b) to
1174        advance over multibyte UTF-8 characters in GlobalReplace.
1176    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1177        difference for some implementation of PCRE in some Windows version.
1179    29. Added some extra testing facilities to pcretest:
1181        \q<number>   in a data line sets the "match limit" value
1182        \Q<number>   in a data line sets the "match recursion limt" value
1183        -S <number>  sets the stack size, where <number> is in megabytes
1185        The -S option isn't available for Windows.
1188    Version 6.6 06-Feb-06
1189    ---------------------
1191     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1192        in pcreposix.h. I have copied the definition from pcre.h.
1194     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1195        because pcre.h is no longer a built file.
1197     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1198        not normally included in the compiled code.
1201    Version 6.5 01-Feb-06
1202    ---------------------
1204     1. When using the partial match feature with pcre_dfa_exec(), it was not
1205        anchoring the second and subsequent partial matches at the new starting
1206        point. This could lead to incorrect results. For example, with the pattern
1207        /1234/, partially matching against "123" and then "a4" gave a match.
1209     2. Changes to pcregrep:
1211        (a) All non-match returns from pcre_exec() were being treated as failures
1212            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1213            error message is output. Some extra information is given for the
1214            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1215            probably the only errors that are likely to be caused by users (by
1216            specifying a regex that has nested indefinite repeats, for instance).
1217            If there are more than 20 of these errors, pcregrep is abandoned.
1219        (b) A binary zero was treated as data while matching, but terminated the
1220            output line if it was written out. This has been fixed: binary zeroes
1221            are now no different to any other data bytes.
1223        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1224            used to set a locale for matching. The --locale=xxxx long option has
1225            been added (no short equivalent) to specify a locale explicitly on the
1226            pcregrep command, overriding the environment variables.
1228        (d) When -B was used with -n, some line numbers in the output were one less
1229            than they should have been.
1231        (e) Added the -o (--only-matching) option.
1233        (f) If -A or -C was used with -c (count only), some lines of context were
1234            accidentally printed for the final match.
1236        (g) Added the -H (--with-filename) option.
1238        (h) The combination of options -rh failed to suppress file names for files
1239            that were found from directory arguments.
1241        (i) Added the -D (--devices) and -d (--directories) options.
1243        (j) Added the -F (--fixed-strings) option.
1245        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1247        (l) Added the --colo(u)r option.
1249        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1250            is not present by default.
1252     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1253        items such as (?R) or (?1), when the recursion could match a number of
1254        alternatives. If it matched one of the alternatives, but subsequently,
1255        outside the recursion, there was a failure, the code tried to back up into
1256        the recursion. However, because of the way PCRE is implemented, this is not
1257        possible, and the result was an incorrect result from the match.
1259        In order to prevent this happening, the specification of recursion has
1260        been changed so that all such subpatterns are automatically treated as
1261        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1263     4. I had overlooked the fact that, in some locales, there are characters for
1264        which isalpha() is true but neither isupper() nor islower() are true. In
1265        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1266        and ordfeminine) are like this. This affected the treatment of \w and \W
1267        when they appeared in character classes, but not when they appeared outside
1268        a character class. The bit map for "word" characters is now created
1269        separately from the results of isalnum() instead of just taking it from the
1270        upper, lower, and digit maps. (Plus the underscore character, of course.)
1272     5. The above bug also affected the handling of POSIX character classes such as
1273        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1274        permanent tables. Instead, the bit maps for such a class were previously
1275        created as the appropriate unions of the upper, lower, and digit bitmaps.
1276        Now they are created by subtraction from the [[:word:]] class, which has
1277        its own bitmap.
1279     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1280        It is created by subtracting the vertical space characters (\x09, \x0a,
1281        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1282        subtraction was done in the overall bitmap for a character class, meaning
1283        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1284        be recognized. This bug has been fixed.
1286     7. Patches from the folks at Google:
1288          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1289          real life, but is still worth protecting against".
1291          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1292          regular expressions".
1294          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1295          have it.
1297          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1298          "configure" and the latter not, in order to fix a problem somebody had
1299          with compiling the Arg class on HP-UX.
1301          (e) Improve the error-handling of the C++ wrapper a little bit.
1303          (f) New tests for checking recursion limiting.
1305     8. The pcre_memmove() function, which is used only if the environment does not
1306        have a standard memmove() function (and is therefore rarely compiled),
1307        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1308        returning a result (though PCRE never actually uses the result).
1310     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1311        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1312        returned instead of calling malloc() with an overflowing number that would
1313        most likely cause subsequent chaos.
1315    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1317    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1318        with this option is matched, the nmatch and pmatch options of regexec() are
1319        ignored.
1321    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1322        provided in case anyone wants to the the POSIX interface with UTF-8
1323        strings.
1325    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1326        C++ linking (needed for some HP-UX environments).
1328    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1329        (unused parameter) and in the pcre_printint() function (omitted "default"
1330        switch label when the default is to do nothing).
1332    15. Added some code to make it possible, when PCRE is compiled as a C++
1333        library, to replace subject pointers for pcre_exec() with a smart pointer
1334        class, thus making it possible to process discontinuous strings.
1336    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1337        much the same function. They were added by different people who were trying
1338        to make PCRE easy to compile on non-Unix systems. It has been suggested
1339        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1340        for compiling on Windows systems. I have therefore replaced it with
1341        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1342        defaults to "extern" for C or "extern C" for C++, which works fine on
1343        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1344        SCOPE with something explicit in config.h. In addition:
1346        (a) pcreposix.h still had just "extern" instead of either of these macros;
1347            I have replaced it with PCRE_DATA_SCOPE.
1349        (b) Functions such as _pcre_xclass(), which are internal to the library,
1350            but external in the C sense, all had PCRE_EXPORT in their definitions.
1351            This is apparently wrong for the Windows case, so I have removed it.
1352            (It makes no difference on Unix-like systems.)
1354    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1355        of recursive calls to match(). This is different to MATCH_LIMIT because
1356        that limits the total number of calls to match(), not all of which increase
1357        the depth of recursion. Limiting the recursion depth limits the amount of
1358        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1359        when PCRE is compiled, and changed at run time. A patch from Google adds
1360        this functionality to the C++ interface.
1362    18. Changes to the handling of Unicode character properties:
1364        (a) Updated the table to Unicode 4.1.0.
1366        (b) Recognize characters that are not in the table as "Cn" (undefined).
1368        (c) I revised the way the table is implemented to a much improved format
1369            which includes recognition of ranges. It now supports the ranges that
1370            are defined in UnicodeData.txt, and it also amalgamates other
1371            characters into ranges. This has reduced the number of entries in the
1372            table from around 16,000 to around 3,000, thus reducing its size
1373            considerably. I realized I did not need to use a tree structure after
1374            all - a binary chop search is just as efficient. Having reduced the
1375            number of entries, I extended their size from 6 bytes to 8 bytes to
1376            allow for more data.
1378        (d) Added support for Unicode script names via properties such as \p{Han}.
1380    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1381        matching that character.
1383    20. When matching a repeated Unicode property with a minimum greater than zero,
1384        (for example \pL{2,}), PCRE could look past the end of the subject if it
1385        reached it while seeking the minimum number of characters. This could
1386        happen only if some of the characters were more than one byte long, because
1387        there is a check for at least the minimum number of bytes.
1389    21. Refactored the implementation of \p and \P so as to be more general, to
1390        allow for more different types of property in future. This has changed the
1391        compiled form incompatibly. Anybody with saved compiled patterns that use
1392        \p or \P will have to recompile them.
1394    22. Added "Any" and "L&" to the supported property types.
1396    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1397        but give a compile time error if the value is greater than 0xff.
1399    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1400        accidentally not being installed or uninstalled.
1402    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1403        made were to insert the current release number. This seemed silly, because
1404        it made things harder for people building PCRE on systems that don't run
1405        "configure". I have turned pcre.h into a distributed file, no longer built
1406        by "configure", with the version identification directly included. There is
1407        no longer a pcre.h.in file.
1409        However, this change necessitated a change to the pcre-config script as
1410        well. It is built from pcre-config.in, and one of the substitutions was the
1411        release number. I have updated configure.ac so that ./configure now finds
1412        the release number by grepping pcre.h.
1414    26. Added the ability to run the tests under valgrind.
1417    Version 6.4 05-Sep-05
1418    ---------------------
1420     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1421        "--" to be printed when multiple files were scanned, even when none of the
1422        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1423        consider it to be a bug, and have restored the previous behaviour.
1425     2. A couple of code tidies to get rid of compiler warnings.
1427     3. The pcretest program used to cheat by referring to symbols in the library
1428        whose names begin with _pcre_. These are internal symbols that are not
1429        really supposed to be visible externally, and in some environments it is
1430        possible to suppress them. The cheating is now confined to including
1431        certain files from the library's source, which is a bit cleaner.
1433     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1434        file's purpose clearer.
1436     5. Reorganized pcre_ucp_findchar().
1439    Version 6.3 15-Aug-05
1440    ---------------------
1442     1. The file libpcre.pc.in did not have general read permission in the tarball.
1444     2. There were some problems when building without C++ support:
1446        (a) If C++ support was not built, "make install" and "make test" still
1447            tried to test it.
1449        (b) There were problems when the value of CXX was explicitly set. Some
1450            changes have been made to try to fix these, and ...
1452        (c) --disable-cpp can now be used to explicitly disable C++ support.
1454        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1455            backslash in a target when C++ was disabled. This confuses some
1456            versions of "make", apparently. Using an intermediate variable solves
1457            this. (Same for CPP_LOBJ.)
1459     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1460        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1461        necessary on certain architectures.
1463     4. Added a setting of -export-symbols-regex to the link command to remove
1464        those symbols that are exported in the C sense, but actually are local
1465        within the library, and not documented. Their names all begin with
1466        "_pcre_". This is not a perfect job, because (a) we have to except some
1467        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1468        available (and never for static libraries). I have made a note to try to
1469        find a way round (a) in the future.
1472    Version 6.2 01-Aug-05
1473    ---------------------
1475     1. There was no test for integer overflow of quantifier values. A construction
1476        such as {1111111111111111} would give undefined results. What is worse, if
1477        a minimum quantifier for a parenthesized subpattern overflowed and became
1478        negative, the calculation of the memory size went wrong. This could have
1479        led to memory overwriting.
1481     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1483     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1484        operating environments where this matters.
1486     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1487        PCRE options from within the C++ wrapper.
1489     5. Named capturing subpatterns were not being correctly counted when a pattern
1490        was compiled. This caused two problems: (a) If there were more than 100
1491        such subpatterns, the calculation of the memory needed for the whole
1492        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1493        back references of the form \12, where the number was greater than 9, were
1494        not recognized as back references, even though there were sufficient
1495        previous subpatterns.
1497     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1498        versions of gcc, e.g. 2.95.4.
1501    Version 6.1 21-Jun-05
1502    ---------------------
1504     1. There was one reference to the variable "posix" in pcretest.c that was not
1505        surrounded by "#if !defined NOPOSIX".
1507     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1508        the cross-check on the old pcre_info() function, for the benefit of the
1509        cut-down version of PCRE that is currently imported into Exim.
1511     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1512        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1513        patterns that start (?i) but I don't think that matters. The use of (?i) is
1514        just an example; this all applies to the other options as well.
1516     4. Since libtool seems to echo the compile commands it is issuing, the output
1517        from "make" can be reduced a bit by putting "@" in front of each libtool
1518        compile command.
1520     5. Patch from the folks at Google for configure.in to be a bit more thorough
1521        in checking for a suitable C++ installation before trying to compile the
1522        C++ stuff. This should fix a reported problem when a compiler was present,
1523        but no suitable headers.
1525     6. The man pages all had just "PCRE" as their title. I have changed them to
1526        be the relevant file name. I have also arranged that these names are
1527        retained in the file doc/pcre.txt, which is a concatenation in text format
1528        of all the man pages except the little individual ones for each function.
1530     7. The NON-UNIX-USE file had not been updated for the different set of source
1531        files that come with release 6. I also added a few comments about the C++
1532        wrapper.
1535    Version 6.0 07-Jun-05
1536    ---------------------
1538     1. Some minor internal re-organization to help with my DFA experiments.
1540     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1541        didn't matter for the library itself when fully configured, but did matter
1542        when compiling without UCP support, or within Exim, where the ucp files are
1543        not imported.
1545     3. Refactoring of the library code to split up the various functions into
1546        different source modules. The addition of the new DFA matching code (see
1547        below) to a single monolithic source would have made it really too
1548        unwieldy, quite apart from causing all the code to be include in a
1549        statically linked application, when only some functions are used. This is
1550        relevant even without the DFA addition now that patterns can be compiled in
1551        one application and matched in another.
1553        The downside of splitting up is that there have to be some external
1554        functions and data tables that are used internally in different modules of
1555        the library but which are not part of the API. These have all had their
1556        names changed to start with "_pcre_" so that they are unlikely to clash
1557        with other external names.
1559     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1560        a different (DFA) algorithm. Although it is slower than the original
1561        function, it does have some advantages for certain types of matching
1562        problem.
1564     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1565        including restarting after a partial match.
1567     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1568        defined when compiling for Windows was sent to me. I have put it into the
1569        code, though I have no means of testing or verifying it.
1571     7. Added the pcre_refcount() auxiliary function.
1573     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1574        match before or at the first newline in the subject string. In pcretest,
1575        the /f option on a pattern can be used to set this.
1577     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1578        would behave wrongly. This has been present in PCRE since release 4.0.
1580    10. A number of changes to the pcregrep command:
1582        (a) Refactored how -x works; insert ^(...)$ instead of setting
1583            PCRE_ANCHORED and checking the length, in preparation for adding
1584            something similar for -w.
1586        (b) Added the -w (match as a word) option.
1588        (c) Refactored the way lines are read and buffered so as to have more
1589            than one at a time available.
1591        (d) Implemented a pcregrep test script.
1593        (e) Added the -M (multiline match) option. This allows patterns to match
1594            over several lines of the subject. The buffering ensures that at least
1595            8K, or the rest of the document (whichever is the shorter) is available
1596            for matching (and similarly the previous 8K for lookbehind assertions).
1598        (f) Changed the --help output so that it now says
1600              -w, --word-regex(p)
1602            instead of two lines, one with "regex" and the other with "regexp"
1603            because that confused at least one person since the short forms are the
1604            same. (This required a bit of code, as the output is generated
1605            automatically from a table. It wasn't just a text change.)
1607        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1608            option but starts with a hyphen. Could be a pattern or a path name
1609            starting with a hyphen, for instance.
1611        (h) "-" can be given as a file name to represent stdin.
1613        (i) When file names are being printed, "(standard input)" is used for
1614            the standard input, for compatibility with GNU grep. Previously
1615            "<stdin>" was used.
1617        (j) The option --label=xxx can be used to supply a name to be used for
1618            stdin when file names are being printed. There is no short form.
1620        (k) Re-factored the options decoding logic because we are going to add
1621            two more options that take data. Such options can now be given in four
1622            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1624        (l) Added the -A, -B, and -C options for requesting that lines of context
1625            around matches be printed.
1627        (m) Added the -L option to print the names of files that do not contain
1628            any matching lines, that is, the complement of -l.
1630        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1631            continue to scan other files.
1633        (o) The -s option was incorrectly implemented. For compatibility with other
1634            greps, it now suppresses the error message for a non-existent or non-
1635            accessible file (but not the return code). There is a new option called
1636            -q that suppresses the output of matching lines, which was what -s was
1637            previously doing.
1639        (p) Added --include and --exclude options to specify files for inclusion
1640            and exclusion when recursing.
1642    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1643        Hopefully, it now does.
1645    12. Missing cast in pcre_study().
1647    13. Added an "uninstall" target to the makefile.
1649    14. Replaced "extern" in the function prototypes in Makefile.in with
1650        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1651        world, but is set differently for Windows.
1653    15. Added a second compiling function called pcre_compile2(). The only
1654        difference is that it has an extra argument, which is a pointer to an
1655        integer error code. When there is a compile-time failure, this is set
1656        non-zero, in addition to the error test pointer being set to point to an
1657        error message. The new argument may be NULL if no error number is required
1658        (but then you may as well call pcre_compile(), which is now just a
1659        wrapper). This facility is provided because some applications need a
1660        numeric error indication, but it has also enabled me to tidy up the way
1661        compile-time errors are handled in the POSIX wrapper.
1663    16. Added VPATH=.libs to the makefile; this should help when building with one
1664        prefix path and installing with another. (Or so I'm told by someone who
1665        knows more about this stuff than I do.)
1667    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1668        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1669        match everything, including newlines. This is not POSIX-compatible, but
1670        somebody wanted the feature. From pcretest it can be activated by using
1671        both the P and the s flags.
1673    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1675    19. libpcre.pc was being incorrectly installed as executable.
1677    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1678        it now also looks for '\r' so that it will work unmodified on Windows.
1680    21. Added Google's contributed C++ wrapper to the distribution.
1682    22. Added some untidy missing memory free() calls in pcretest, to keep
1683        Electric Fence happy when testing.
1687    Version 5.0 13-Sep-04
1688    ---------------------
1690     1. Internal change: literal characters are no longer packed up into items
1691        containing multiple characters in a single byte-string. Each character
1692        is now matched using a separate opcode. However, there may be more than one
1693        byte in the character in UTF-8 mode.
1695     2. The pcre_callout_block structure has two new fields: pattern_position and
1696        next_item_length. These contain the offset in the pattern to the next match
1697        item, and its length, respectively.
1699     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1700        insertion of callouts before each pattern item. Added the /C option to
1701        pcretest to make use of this.
1703     4. On the advice of a Windows user, the lines
1705          #if defined(_WIN32) || defined(WIN32)
1706          _setmode( _fileno( stdout ), 0x8000 );
1707          #endif  /* defined(_WIN32) || defined(WIN32) */
1709        have been added to the source of pcretest. This apparently does useful
1710        magic in relation to line terminators.
1712     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1713        for the benefit of those environments where the "b" makes a difference.
1715     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1716        to know about it. I have put a hack into configure.in that adds in code
1717        to set GCC=yes if CC=icc. This seems to end up at a point in the
1718        generated configure script that is early enough to affect the setting of
1719        compiler options, which is what is needed, but I have no means of testing
1720        whether it really works. (The user who reported this had patched the
1721        generated configure script, which of course I cannot do.)
1723        LATER: After change 22 below (new libtool files), the configure script
1724        seems to know about icc (and also ecc). Therefore, I have commented out
1725        this hack in configure.in.
1727     7. Added support for pkg-config (2 patches were sent in).
1729     8. Negated POSIX character classes that used a combination of internal tables
1730        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1731        [[:^ascii]]. Typically, they would match almost any characters. The other
1732        POSIX classes were not broken in this way.
1734     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1735        to find the match, as PCRE was deluded into thinking that the match had to
1736        start at the start point or following a newline. The same bug applied to
1737        patterns with negative forward assertions or any backward assertions
1738        preceding ".*" at the start, unless the pattern required a fixed first
1739        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1741    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1742        starting at the last subject character, bytes beyond the end of the subject
1743        string were read.
1745    11. Renamed the variable "class" as "classbits" to make life easier for C++
1746        users. (Previously there was a macro definition, but it apparently wasn't
1747        enough.)
1749    12. Added the new field "tables" to the extra data so that tables can be passed
1750        in at exec time, or the internal tables can be re-selected. This allows
1751        a compiled regex to be saved and re-used at a later time by a different
1752        program that might have everything at different addresses.
1754    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1755        -R library as well as a -L library.
1757    14. The debugging options of pcretest (-d on the command line or D on a
1758        pattern) showed incorrect output for anything following an extended class
1759        that contained multibyte characters and which was followed by a quantifier.
1761    15. Added optional support for general category Unicode character properties
1762        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1763        support. It adds about 90K to the size of the library. The meanings of the
1764        inbuilt class escapes such as \d and \s have NOT been changed.
1766    16. Updated pcredemo.c to include calls to free() to release the memory for the
1767        compiled pattern.
1769    17. The generated file chartables.c was being created in the source directory
1770        instead of in the building directory. This caused the build to fail if the
1771        source directory was different from the building directory, and was
1772        read-only.
1774    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1775        file. No doubt somebody will tell me if they don't make sense... Also added
1776        Dan Mooney's comments about building on OpenVMS.
1778    19. Added support for partial matching via the PCRE_PARTIAL option for
1779        pcre_exec() and the \P data escape in pcretest.
1781    20. Extended pcretest with 3 new pattern features:
1783        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1784              write the compiled pattern to the file whose name is "rest-of-line".
1785              This is a straight binary dump of the data, with the saved pointer to
1786              the character tables forced to be NULL. The study data, if any, is
1787              written too. After writing, pcretest reads a new pattern.
1789        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1790              compiled pattern from the given file. There must not be any
1791              occurrences of "<" in the file name (pretty unlikely); if there are,
1792              pcretest will instead treat the initial "<" as a pattern delimiter.
1793              After reading in the pattern, pcretest goes on to read data lines as
1794              usual.
1796        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1797              and 16-bit fields in a compiled pattern, to simulate a pattern that
1798              was compiled on a host of opposite endianness.
1800    21. The pcre-exec() function can now cope with patterns that were compiled on
1801        hosts of opposite endianness, with this restriction:
1803          As for any compiled expression that is saved and used later, the tables
1804          pointer field cannot be preserved; the extra_data field in the arguments
1805          to pcre_exec() should be used to pass in a tables address if a value
1806          other than the default internal tables were used at compile time.
1808    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1809        now diagnosed as an error. Previously, most of the time, a negative number
1810        would have been treated as zero, but if in addition "ovector" was passed as
1811        NULL, a crash could occur.
1813    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1814        new versions from the libtool 1.5 distribution (the last one is a copy of
1815        a file called libtool.m4). This seems to have fixed the need to patch
1816        "configure" to support Darwin 1.3 (which I used to do). However, I still
1817        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1818        workstation).
1820    24. Changed the PCRE licence to be the more standard "BSD" licence.
1823    Version 4.5 01-Dec-03
1824    ---------------------
1826     1. There has been some re-arrangement of the code for the match() function so
1827        that it can be compiled in a version that does not call itself recursively.
1828        Instead, it keeps those local variables that need separate instances for
1829        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1830        needs to "recurse". Keeping track of where control must go is done by means
1831        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1832        hide most of the details from the main code, and operates only if
1833        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1834        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1835        operating.
1837        To make it easier for callers to provide specially tailored get/free
1838        functions for this usage, two new functions, pcre_stack_malloc, and
1839        pcre_stack_free, are used. They are always called in strict stacking order,
1840        and the size of block requested is always the same.
1842        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1843        PCRE has been compiled to use the stack or the heap for recursion. The
1844        -C option of pcretest uses this to show which version is compiled.
1846        A new data escape \S, is added to pcretest; it causes the amounts of store
1847        obtained and freed by both kinds of malloc/free at match time to be added
1848        to the output.
1850     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1851        what's available on my current Linux desktop machine.
1853     3. When matching a UTF-8 string, the test for a valid string at the start has
1854        been extended. If start_offset is not zero, PCRE now checks that it points
1855        to a byte that is the start of a UTF-8 character. If not, it returns
1856        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1857        this is necessary because there may be backward assertions in the pattern.
1858        When matching the same subject several times, it may save resources to use
1859        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1861     4. The code for checking the validity of UTF-8 strings has been tightened so
1862        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1863        containing "overlong sequences".
1865     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1866        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1867        should have been "&", but it just so happened that all the cases this let
1868        through by mistake were picked up later in the function.
1870     6. I had used a variable called "isblank" - this is a C99 function, causing
1871        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1873     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1874        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1875        so the version is shown; (c) stop "make test" echoing "./RunTest".
1877     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1879     9. The prototype for memmove() for systems that don't have it was using
1880        size_t, but the inclusion of the header that defines size_t was later. I've
1881        moved the #includes for the C headers earlier to avoid this.
1883    10. Added some adjustments to the code to make it easier to compiler on certain
1884        special systems:
1886          (a) Some "const" qualifiers were missing.
1887          (b) Added the macro EXPORT before all exported functions; by default this
1888              is defined to be empty.
1889          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1890              that it reads its output file name as an argument instead of writing
1891              to the standard output and assuming this can be redirected.
1893    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1894        class containing characters with values greater than 255, PCRE compilation
1895        went into a loop.
1897    12. A recursive reference to a subpattern that was within another subpattern
1898        that had a minimum quantifier of zero caused PCRE to crash. For example,
1899        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1900        recursion. If the recursively-called subpattern itself had a zero repeat,
1901        that was OK.
1903    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1904        buffer into which it was copied (for escape processing) was still set at
1905        1024, so long lines caused crashes.
1907    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1908        "internal error: code overflow...". This applied to any character class
1909        that was followed by a possessive quantifier.
1911    15. Modified the Makefile to add libpcre.la as a prerequisite for
1912        libpcreposix.la because I was told this is needed for a parallel build to
1913        work.
1915    16. If a pattern that contained .* following optional items at the start was
1916        studied, the wrong optimizing data was generated, leading to matching
1917        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1918        matching string must start with a or b or c. The correct conclusion for
1919        this pattern is that a match can start with any character.
1922    Version 4.4 13-Aug-03
1923    ---------------------
1925     1. In UTF-8 mode, a character class containing characters with values between
1926        127 and 255 was not handled correctly if the compiled pattern was studied.
1927        In fixing this, I have also improved the studying algorithm for such
1928        classes (slightly).
1930     2. Three internal functions had redundant arguments passed to them. Removal
1931        might give a very teeny performance improvement.
1933     3. Documentation bug: the value of the capture_top field in a callout is *one
1934        more than* the number of the hightest numbered captured substring.
1936     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1937        in incorrectly linking with a previously installed version. They now link
1938        explicitly with libpcre.la.
1940     5. configure.in no longer needs to recognize Cygwin specially.
1942     6. A problem in pcre.in for Windows platforms is fixed.
1944     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1945        pcretest, it used to include the size of the study block as part of its
1946        output. Unfortunately, the structure contains a field that has a different
1947        size on different hardware architectures. This meant that the tests that
1948        showed this size failed. As the block is currently always of a fixed size,
1949        this information isn't actually particularly useful in pcretest output, so
1950        I have just removed it.
1952     8. Three pre-processor statements accidentally did not start in column 1.
1953        Sadly, there are *still* compilers around that complain, even though
1954        standard C has not required this for well over a decade. Sigh.
1956     9. In pcretest, the code for checking callouts passed small integers in the
1957        callout_data field, which is a void * field. However, some picky compilers
1958        complained about the casts involved for this on 64-bit systems. Now
1959        pcretest passes the address of the small integer instead, which should get
1960        rid of the warnings.
1962    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1963        both compile and run time, and gives an error if an invalid UTF-8 sequence
1964        is found. There is a option for disabling this check in cases where the
1965        string is known to be correct and/or the maximum performance is wanted.
1967    11. In response to a bug report, I changed one line in Makefile.in from
1969            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1970        to
1971            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1973        to look similar to other lines, but I have no way of telling whether this
1974        is the right thing to do, as I do not use Windows. No doubt I'll get told
1975        if it's wrong...
1978    Version 4.3 21-May-03
1979    ---------------------
1981    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1982       Makefile.
1984    2. Some refactoring to improve the quality of the code:
1986       (i)   The utf8_table... variables are now declared "const".
1988       (ii)  The code for \cx, which used the "case flipping" table to upper case
1989             lower case letters, now just substracts 32. This is ASCII-specific,
1990             but the whole concept of \cx is ASCII-specific, so it seems
1991             reasonable.
1993       (iii) PCRE was using its character types table to recognize decimal and
1994             hexadecimal digits in the pattern. This is silly, because it handles
1995             only 0-9, a-f, and A-F, but the character types table is locale-
1996             specific, which means strange things might happen. A private
1997             table is now used for this - though it costs 256 bytes, a table is
1998             much faster than multiple explicit tests. Of course, the standard
1999             character types table is still used for matching digits in subject
2000             strings against \d.
2002       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2003             ending in _t are). So I've renamed it as ESC_tee.
2005    3. The first argument for regexec() in the POSIX wrapper should have been
2006       defined as "const".
2008    4. Changed pcretest to use malloc() for its buffers so that they can be
2009       Electric Fenced for debugging.
2011    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2012       to read one or more bytes before the start of the subject string. Often this
2013       had no effect on PCRE's behaviour, but in some circumstances it could
2014       provoke a segmentation fault.
2016    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2017       to try to read one or more bytes before the start of the subject string.
2019    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2020       UTF-8 support could misbehave in various ways if the subject string
2021       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2022       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2023       back over UTF-8 characters.)
2026    Version 4.2 14-Apr-03
2027    ---------------------
2029    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2031    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2032         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2033         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2034         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2035         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2036           and BUILD_EXEEXT
2037         Note: automatic setting of the BUILD variables is not yet working
2038         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2039           compile-time but not at link-time
2040         [LINK]: use for linking executables only
2041         make different versions for Windows and non-Windows
2042         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2043           libraries
2044         [LINK_FOR_BUILD]: new variable
2045         [OBJEXT]: use throughout
2046         [EXEEXT]: use throughout
2047         <winshared>: new target
2048         <wininstall>: new target
2049         <dftables.o>: use native compiler
2050         <dftables>: use native linker
2051         <install>: handle Windows platform correctly
2052         <clean>: ditto
2053         <check>: ditto
2054         copy DLL to top builddir before testing
2056       As part of these changes, -no-undefined was removed again. This was reported
2057       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2058       in any case.
2060    3. Some tidies to get rid of compiler warnings:
2062       . In the match_data structure, match_limit was an unsigned long int, whereas
2063         match_call_count was an int. I've made them both unsigned long ints.
2065       . In pcretest the fact that a const uschar * doesn't automatically cast to
2066         a void * provoked a warning.
2068       . Turning on some more compiler warnings threw up some "shadow" variables
2069         and a few more missing casts.
2071    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2072       option, a class that contained a single character with a value between 128
2073       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2075    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2076       option, a class that contained several characters, but with at least one
2077       whose value was between 128 and 255 caused PCRE to crash.
2080    Version 4.1 12-Mar-03
2081    ---------------------
2083    1. Compiling with gcc -pedantic found a couple of places where casts were
2084    needed, and a string in dftables.c that was longer than standard compilers are
2085    required to support.
2087    2. Compiling with Sun's compiler found a few more places where the code could
2088    be tidied up in order to avoid warnings.
2090    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2091    first of these names is deprecated in the latest Autoconf in favour of the name
2092    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2093    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2094    analogy I have changed it to CFLAGS_FOR_BUILD.
2096    4. Added -no-undefined to the linking command in the Makefile, because this is
2097    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2098    linking step for the pcreposix library.
2100    5. PCRE was failing to diagnose the case of two named groups with the same
2101    name.
2103    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2104    literal character that is needed in the subject for a match, and scans along to
2105    ensure that it is present before embarking on the full matching process. This
2106    saves time in cases of nested unlimited repeats that are never going to match.
2107    Problem: the scan can take a lot of time if the subject is very long (e.g.
2108    megabytes), thus penalizing straightforward matches. It is now done only if the
2109    amount of subject to be scanned is less than 1000 bytes.
2111    7. A lesser problem with the same optimization is that it was recording the
2112    first character of an anchored pattern as "needed", thus provoking a search
2113    right along the subject, even when the first match of the pattern was going to
2114    fail. The "needed" character is now not set for anchored patterns, unless it
2115    follows something in the pattern that is of non-fixed length. Thus, it still
2116    fulfils its original purpose of finding quick non-matches in cases of nested
2117    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2120    Version 4.0 17-Feb-03
2121    ---------------------
2123    1. If a comment in an extended regex that started immediately after a meta-item
2124    extended to the end of string, PCRE compiled incorrect data. This could lead to
2125    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2127    2. Moved to autoconf 2.53 and libtool 1.4.2.
2129    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2130    the special perltest8 script is no longer needed - all the tests can be run
2131    from a single perltest script.
2133    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2134    by \s. It has now been removed in PCRE. This means it isn't recognized as
2135    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2136    class [:space:] *does* include VT, thereby creating a mess.
2138    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2139    space and tab.
2141    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2142    its new features into the main test script, reducing the number of scripts.
2144    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2145    were backward compatible, and made the (?i) apply to the whole pattern, as if
2146    /i were given. Now it behaves more logically, and applies the option setting
2147    only to what follows. PCRE has been changed to follow suit. However, if it
2148    finds options settings right at the start of the pattern, it extracts them into
2149    the global options, as before. Thus, they show up in the info data.
2151    8. Added support for the \Q...\E escape sequence. Characters in between are
2152    treated as literals. This is slightly different from Perl in that $ and @ are
2153    also handled as literals inside the quotes. In Perl, they will cause variable
2154    interpolation. Note the following examples:
2156        Pattern            PCRE matches      Perl matches
2158        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2159        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2160        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2162    For compatibility with Perl, \Q...\E sequences are recognized inside character
2163    classes as well as outside them.
2165    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2166    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2167    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2168    signed/unsigned warnings.
2170    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2171    option for pcretest, so I've replaced it by a simple function that does just
2172    that job.
2174    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2175    "pcregrep -".
2177    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2178    Java package. This provides some syntactic sugar for simple cases of what my
2179    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2180    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2181    item, you can use this simplified notation. Note that only makes sense with
2182    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2183    greediness, whatever the setting of the PCRE_UNGREEDY option.
2185    13. A change of greediness default within a pattern was not taking effect at
2186    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2187    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2188    was abstracted outside.
2190    14. PCRE now supports the \G assertion. It is true when the current matching
2191    position is at the start point of the match. This differs from \A when the
2192    starting offset is non-zero. Used with the /g option of pcretest (or similar
2193    code), it works in the same way as it does for Perl's /g option. If all
2194    alternatives of a regex begin with \G, the expression is anchored to the start
2195    match position, and the "anchored" flag is set in the compiled expression.
2197    15. Some bugs concerning the handling of certain option changes within patterns
2198    have been fixed. These applied to options other than (?ims). For example,
2199    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2200    been the other way round. Some of this was related to change 7 above.
2202    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2203    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2204    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2205    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2207    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2208    mode. Unlike ".", it always matches newline, whatever the setting of
2209    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2210    assertions. Perl allows it, but it doesn't (in general) work because it can't
2211    calculate the length of the lookbehind. At least, that's the case for Perl
2212    5.8.0 - I've been told they are going to document that it doesn't work in
2213    future.
2215    18. Added an error diagnosis for escapes that PCRE does not support: these are
2216    \L, \l, \N, \P, \p, \U, \u, and \X.
2218    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2219    reading past the end of the pattern in cases such as /[abcd/.
2221    20. PCRE was getting more memory than necessary for patterns with classes that
2222    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2224    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2225    compiling PCRE for use with Virtual Pascal.
2227    22. Small fix to the Makefile to make it work properly if the build is done
2228    outside the source tree.
2230    23. Added a new extension: a condition to go with recursion. If a conditional
2231    subpattern starts with (?(R) the "true" branch is used if recursion has
2232    happened, whereas the "false" branch is used only at the top level.
2234    24. When there was a very long string of literal characters (over 255 bytes
2235    without UTF support, over 250 bytes with UTF support), the computation of how
2236    much memory was required could be incorrect, leading to segfaults or other
2237    strange effects.
2239    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2240    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2241    there was a subsequent back reference to those brackets. This meant that, for
2242    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2243    possible to check for precisely this case. All we can do is abandon the
2244    optimization if .* occurs inside capturing brackets when there are any back
2245    references whatsoever. (See below for a better fix that came later.)
2247    26. The handling of the optimization for finding the first character of a
2248    non-anchored pattern, and for finding a character that is required later in the
2249    match were failing in some cases. This didn't break the matching; it just
2250    failed to optimize when it could. The way this is done has been re-implemented.
2252    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2254    28. Added a new feature that provides some of the functionality that Perl
2255    provides with (?{...}). The facility is termed a "callout". The way it is done
2256    in PCRE is for the caller to provide an optional function, by setting
2257    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2258    global variable. By default it is unset, which disables all calling out. To get
2259    the function called, the regex must include (?C) at appropriate points. This
2260    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2261    This provides a means of identifying different callout points. When PCRE
2262    reaches such a point in the regex, if pcre_callout has been set, the external
2263    function is called. It is provided with data in a structure called
2264    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2265    matching continues; if it returns a non-zero value, the match at the current
2266    point fails. However, backtracking will occur if possible. [This was changed
2267    later and other features added - see item 49 below.]
2269    29. pcretest is upgraded to test the callout functionality. It provides a
2270    callout function that displays information. By default, it shows the start of
2271    the match and the current position in the text. There are some new data escapes
2272    to vary what happens:
2274        \C+         in addition, show current contents of captured substrings
2275        \C-         do not supply a callout function
2276        \C!n        return 1 when callout number n is reached
2277        \C!n!m      return 1 when callout number n is reached for the mth time
2279    30. If pcregrep was called with the -l option and just a single file name, it
2280    output "<stdin>" if a match was found, instead of the file name.
2282    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2283    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2284    pcre_exec(). This saves a malloc/free per call. The default value of
2285    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2286    when configuring.
2288    32. The default maximum size of a compiled pattern is 64K. There have been a
2289    few cases of people hitting this limit. The code now uses macros to handle the
2290    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2291    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2292    configuring. Tests 2 and 5 work only with 2-byte links because they output
2293    debugging information about compiled patterns.
2295    33. Internal code re-arrangements:
2297    (a) Moved the debugging function for printing out a compiled regex into
2298        its own source file (printint.c) and used #include to pull it into
2299        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2300        separate copies.
2302    (b) Defined the list of op-code names for debugging as a macro in
2303        internal.h so that it is next to the definition of the opcodes.
2305    (c) Defined a table of op-code lengths for simpler skipping along compiled
2306        code. This is again a macro in internal.h so that it is next to the
2307        definition of the opcodes.
2309    34. Added support for recursive calls to individual subpatterns, along the
2310    lines of Robin Houston's patch (but implemented somewhat differently).
2312    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2313    allow it to read and process whole directories in Win32. This code was
2314    contributed by Lionel Fourquaux; it has not been tested by me.
2316    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2317    used to name a group. Names consist of alphanumerics and underscores, and must
2318    be unique. Back references use the syntax (?P=name) and recursive calls use
2319    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2320    numbers. The function pcre_fullinfo() can be used after compilation to extract
2321    a name/number map. There are three relevant calls:
2323      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2324      PCRE_INFO_NAMECOUNT            yields the number of entries
2325      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2327    The map is a vector of fixed-size entries. The size of each entry depends on
2328    the length of the longest name used. The first two bytes of each entry are the
2329    group number, most significant byte first. There follows the corresponding
2330    name, zero terminated. The names are in alphabetical order.
2332    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2333    case instead of 255. Making it the same both with and without UTF-8 support
2334    means that the same test output works with both.
2336    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2337    calling malloc() with a zero argument.
2339    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2340    optimization. I've improved things by keeping a bitmap of backreferences with
2341    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2342    fact referenced, the optimization can be applied. It is unlikely that a
2343    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2344    the match to follow \n) will appear inside brackets with a number greater than
2345    31, but if it does, any back reference > 31 suppresses the optimization.
2347    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2348    of disabling numbered capturing parentheses. Any opening parenthesis that is
2349    not followed by ? behaves as if it were followed by ?: but named parentheses
2350    can still be used for capturing (and they will acquire numbers in the usual
2351    way).
2353    41. Redesigned the return codes from the match() function into yes/no/error so
2354    that errors can be passed back from deep inside the nested calls. A malloc
2355    failure while inside a recursive subpattern call now causes the
2356    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2358    42. It is now possible to set a limit on the number of times the match()
2359    function is called in a call to pcre_exec(). This facility makes it possible to
2360    limit the amount of recursion and backtracking, though not in a directly
2361    obvious way, because the match() function is used in a number of different
2362    circumstances. The count starts from zero for each position in the subject
2363    string (for non-anchored patterns). The default limit is, for compatibility, a
2364    large number, namely 10 000 000. You can change this in two ways:
2366    (a) When configuring PCRE before making, you can use --with-match-limit=n
2367        to set a default value for the compiled library.
2369    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2370        a different value is set. See 45 below.
2372    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2374    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2375    of things that can be changed at compile time. The first argument specifies
2376    what is wanted and the second points to where the information is to be placed.
2377    The current list of available information is:
2379      PCRE_CONFIG_UTF8
2381    The output is an integer that is set to one if UTF-8 support is available;
2382    otherwise it is set to zero.
2386    The output is an integer that it set to the value of the code that is used for
2387    newline. It is either LF (10) or CR (13).
2391    The output is an integer that contains the number of bytes used for internal
2392    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2396    The output is an integer that contains the threshold above which the POSIX
2397    interface uses malloc() for output vectors. See item 31 above.
2401    The output is an unsigned integer that contains the default limit of the number
2402    of match() calls in a pcre_exec() execution. See 42 above.
2404    44. pcretest has been upgraded by the addition of the -C option. This causes it
2405    to extract all the available output from the new pcre_config() function, and to
2406    output it. The program then exits immediately.
2408    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2409    order to support additional features. One way would have been to define
2410    pcre_exec2() (for example) with extra arguments, but this would not have been
2411    extensible, and would also have required all calls to the original function to
2412    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2413    is used for passing in "extra" data from pcre_study().
2415    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2416    contains the following fields:
2418      flags         a bitmap indicating which of the following fields are set
2419      study_data    opaque data from pcre_study()
2420      match_limit   a way of specifying a limit on match() calls for a specific
2421                      call to pcre_exec()
2422      callout_data  data for callouts (see 49 below)
2424    The flag bits are also defined in pcre.h, and are
2430    The pcre_study() function now returns one of these new pcre_extra blocks, with
2431    the actual study data pointed to by the study_data field, and the
2432    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2433    before. That is, this change is entirely upwards-compatible and requires no
2434    change to existing code.
2436    If you want to pass in additional data to pcre_exec(), you can either place it
2437    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2438    block.
2440    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2441    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2442    times with different match limits, until it finds the minimum value needed for
2443    pcre_exec() to complete. The value is then output. This can be instructive; for
2444    most simple matches the number is quite small, but for pathological cases it
2445    gets very large very quickly.
2447    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2448    returns the size of the data block pointed to by the study_data field in a
2449    pcre_extra block, that is, the value that was passed as the argument to
2450    pcre_malloc() when PCRE was getting memory in which to place the information
2451    created by pcre_study(). The fourth argument should point to a size_t variable.
2452    pcretest has been extended so that this information is shown after a successful
2453    pcre_study() call when information about the compiled regex is being displayed.
2455    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2456    because what follows is always an absolute path. (Later: it turns out that this
2457    is more than cosmetic for MinGW, because it doesn't like empty path
2458    components.)
2460    49. Some changes have been made to the callout feature (see 28 above):
2462    (i)  A callout function now has three choices for what it returns:
2464           0  =>  success, carry on matching
2465         > 0  =>  failure at this point, but backtrack if possible
2466         < 0  =>  serious error, return this value from pcre_exec()
2468         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2469         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2470         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2471         use by callout functions. It will never be used by PCRE itself.
2473    (ii) The pcre_extra structure (see 45 above) has a void * field called
2474         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2475         pcre_callout_block structure has a field of the same name. The contents of
2476         the field passed in the pcre_extra structure are passed to the callout
2477         function in the corresponding field in the callout block. This makes it
2478         easier to use the same callout-containing regex from multiple threads. For
2479         testing, the pcretest program has a new data escape
2481           \C*n        pass the number n (may be negative) as callout_data
2483         If the callout function in pcretest receives a non-zero value as
2484         callout_data, it returns that value.
2486    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2487    there were some redundant $(CFLAGS) in commands that are now specified as
2488    $(LINK), which already includes $(CFLAGS).
2490    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2491    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2492    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2493    one-byte characters throughout. Note that case-insensitive matching applies
2494    only to characters whose values are less than 256. PCRE doesn't support the
2495    notion of cases for higher-valued characters.
2497    (i)   A character class whose characters are all within 0-255 is handled as
2498          a bit map, and the map is inverted for negative classes. Previously, a
2499          character > 255 always failed to match such a class; however it should
2500          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2502    (ii)  A negated character class with a single character < 255 is coded as
2503          "not this character" (OP_NOT). This wasn't working properly when the test
2504          character was multibyte, either singly or repeated.
2506    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2507          mode, for example: \x{100}{2,3}.
2509    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2510          singly or repeated) now correctly test multibyte characters. However,
2511          PCRE doesn't recognize any characters with values greater than 255 as
2512          digits, spaces, or word characters. Such characters always match \D, \S,
2513          and \W, and never match \d, \s, or \w.
2515    (v)   Classes may now contain characters and character ranges with values
2516          greater than 255. For example: [ab\x{100}-\x{400}].
2518    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2519          PCRE in UTF-8 mode.
2521    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2522    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2523    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2524    value.)
2526    53. The single man page has become too large. I have therefore split it up into
2527    a number of separate man pages. These also give rise to individual HTML pages;
2528    these are now put in a separate directory, and there is an index.html page that
2529    lists them all. Some hyperlinking between the pages has been installed.
2531    54. Added convenience functions for handling named capturing parentheses.
2533    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2534    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2535    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2536    are faulted.
2538    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2539    calling configure. These values are used when compiling the dftables.c program
2540    which is run to generate the source of the default character tables. They
2541    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2542    you will need to set these values.
2544    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2547    Version 3.9 02-Jan-02
2548    ---------------------
2550    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2552    2. If --disable-static was given, the building process failed when trying to
2553    build pcretest and pcregrep. (For some reason it was using libtool to compile
2554    them, which is not right, as they aren't part of the library.)
2557    Version 3.8 18-Dec-01
2558    ---------------------
2560    1. The experimental UTF-8 code was completely screwed up. It was packing the
2561    bytes in the wrong order. How dumb can you get?
2564    Version 3.7 29-Oct-01
2565    ---------------------
2567    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2568    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2569    this didn't happen under Solaris 8, where I normally test things.
2571    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2572    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2573    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2574    this fix an hour or so after the initial 3.7 release.)
2577    Version 3.6 23-Oct-01
2578    ---------------------
2580    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2581    offsets passed as NULL with zero offset count.
2583    2. The config.guess and config.sub files had not been updated when I moved to
2584    the latest autoconf.
2587  Version 3.5 15-Aug-01  Version 3.5 15-Aug-01
2588  ---------------------  ---------------------

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