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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.0 02 Jul-08
5    ---------------------
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
17    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18        a group with a zero qualifier. The result of the study could be incorrect,
19        or the function might crash, depending on the pattern.
21    4.  Caseless matching was not working for non-ASCII characters in back
22        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23        It now works when Unicode Property Support is available.
25    5.  In pcretest, an escape such as \x{de} in the data was always generating
26        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
27        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
28        truncation.
30    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
32    7.  Added two (int) casts to pcregrep when printing the difference of two
33        pointers, in case they are 64-bit values.
35    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
36        test 2 if it fails.
39    Version 7.7 07-May-08
40    ---------------------
42    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
43        a string to a long long, pretend we don't even have a long long." This is
44        done by checking for the strtoq, strtoll, and _strtoi64 functions.
46    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
47        pre-7.6 versions, which defined a global no_arg variable instead of putting
48        it in the RE class. (See also #8 below.)
50    3.  Remove a line of dead code, identified by coverity and reported by Nuno
51        Lopes.
53    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
55        (1) The include/exclude patterns were being applied to the whole pathnames
56            of files, instead of just to the final components.
58        (2) If there was more than one level of directory, the subdirectories were
59            skipped unless they satisfied the include/exclude conditions. This is
60            inconsistent with GNU grep (and could even be seen as contrary to the
61            pcregrep specification - which I improved to make it absolutely clear).
62            The action now is always to scan all levels of directory, and just
63            apply the include/exclude patterns to regular files.
65    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
66        --exclude_dir in the tests to avoid scanning .svn directories.
68    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
69        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
70        doesn't support NULs in patterns.
72    7.  Added some missing "const"s to declarations of static tables in
73        pcre_compile.c and pcre_dfa_exec.c.
75    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
76        caused by fix #2  above. (Subsequently also a second patch to fix the
77        first patch. And a third patch - this was a messy problem.)
79    9.  Applied Craig's patch to remove the use of push_back().
81    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
82        matching function regexec().
84    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
85        which, however, unlike Perl's \g{...}, are subroutine calls, not back
86        references. PCRE supports relative numbers with this syntax (I don't think
87        Oniguruma does).
89    12. Previously, a group with a zero repeat such as (...){0} was completely
90        omitted from the compiled regex. However, this means that if the group
91        was called as a subroutine from elsewhere in the pattern, things went wrong
92        (an internal error was given). Such groups are now left in the compiled
93        pattern, with a new opcode that causes them to be skipped at execution
94        time.
96    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
97        to the way PCRE behaves:
99        (a) A lone ] character is dis-allowed (Perl treats it as data).
101        (b) A back reference to an unmatched subpattern matches an empty string
102            (Perl fails the current match path).
104        (c) A data ] in a character class must be notated as \] because if the
105            first data character in a class is ], it defines an empty class. (In
106            Perl it is not possible to have an empty class.) The empty class []
107            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
108            The negative empty class [^] matches any one character, independently
109            of the DOTALL setting.
111    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
112        non-existent subpattern following a character class starting with ']' and
113        containing () gave an internal compiling error instead of "reference to
114        non-existent subpattern". Fortunately, when the pattern did exist, the
115        compiled code was correct. (When scanning forwards to check for the
116        existencd of the subpattern, it was treating the data ']' as terminating
117        the class, so got the count wrong. When actually compiling, the reference
118        was subsequently set up correctly.)
120    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
121        it was being rejected as not supported by pcre_dfa_exec(), even though
122        other assertions are supported. I have made pcre_dfa_exec() support
123        (*FAIL).
125    16. The implementation of 13c above involved the invention of a new opcode,
126        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
127        cannot be changed at match time, I realized I could make a small
128        improvement to matching performance by compiling OP_ALLANY instead of
129        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
130        on the OP_ANY path.
132    17. Compiling pcretest on Windows with readline support failed without the
133        following two fixes: (1) Make the unistd.h include conditional on
134        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
136    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
137        ncurses library to be included for pcretest when ReadLine support is
138        requested, but also to allow for it to be overridden. This patch came from
139        Daniel Bergström.
141    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
142        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
143        any errors with the current Unicode tables. Thanks to Peter Kankowski for
144        spotting this.
147    Version 7.6 28-Jan-08
148    ---------------------
150    1.  A character class containing a very large number of characters with
151        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
152        overflow.
154    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
155        HAVE_LONG_LONG is not defined.
157    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
158        bring them up to date and include new features. This patch includes:
160        - Fixed PH's badly added libz and libbz2 support.
161        - Fixed a problem with static linking.
162        - Added pcredemo. [But later removed - see 7 below.]
163        - Fixed dftables problem and added an option.
164        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
165            HAVE_LONG_LONG.
166        - Added readline support for pcretest.
167        - Added an listing of the option settings after cmake has run.
169    4.  A user submitted a patch to Makefile that makes it easy to create
170        "pcre.dll" under mingw when using Configure/Make. I added stuff to
171        Makefile.am that cause it to include this special target, without
172        affecting anything else. Note that the same mingw target plus all
173        the other distribution libraries and programs are now supported
174        when configuring with CMake (see 6 below) instead of with
175        Configure/Make.
177    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
178        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
179        exported in the Windows port". It has not yet been confirmed that the patch
180        solves the problem, but it does no harm.
182    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
183        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
184        with CMake, and also correct the comment about stack recursion.
186    7.  Remove the automatic building of pcredemo from the ./configure system and
187        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
188        of a program that users should build themselves after PCRE is installed, so
189        building it automatically is not really right. What is more, it gave
190        trouble in some build environments.
192    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
195    Version 7.5 10-Jan-08
196    ---------------------
198    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
199        values in parens when parsing an RE using the C++ wrapper."
201    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
202        Characters greater than 255 were excluded from the class instead of being
203        included.
205    3.  The same bug as (2) above applied to negated POSIX classes such as
206        [:^space:].
208    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
209        defined or documented. It seems to have been a typo for PCRE_STATIC, so
210        I have changed it.
212    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
213        first named subpattern) and a construct such as (?&a) would reference the
214        first named subpattern whose name started with "a" (in other words, the
215        length check was missing). Both these problems are fixed. "Subpattern name
216        expected" is now given for (?&) (a zero-length name), and this patch also
217        makes it give the same error for \k'' (previously it complained that that
218        was a reference to a non-existent subpattern).
220    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
221        this is right because (?- can be followed by option settings as well as by
222        digits. I have, however, made the messages clearer.
224    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
225        than the number used in the conditional) now cause a compile-time error.
226        This is actually not compatible with Perl, which accepts such patterns, but
227        treats the conditional as always being FALSE (as PCRE used to), but it
228        seems to me that giving a diagnostic is better.
230    8.  Change "alphameric" to the more common word "alphanumeric" in comments
231        and messages.
233    9.  Fix two occurrences of "backslash" in comments that should have been
234        "backspace".
236    10. Remove two redundant lines of code that can never be obeyed (their function
237        was moved elsewhere).
239    11. The program that makes PCRE's Unicode character property table had a bug
240        which caused it to generate incorrect table entries for sequences of
241        characters that have the same character type, but are in different scripts.
242        It amalgamated them into a single range, with the script of the first of
243        them. In other words, some characters were in the wrong script. There were
244        thirteen such cases, affecting characters in the following ranges:
246          U+002b0 - U+002c1
247          U+0060c - U+0060d
248          U+0061e - U+00612
249          U+0064b - U+0065e
250          U+0074d - U+0076d
251          U+01800 - U+01805
252          U+01d00 - U+01d77
253          U+01d9b - U+01dbf
254          U+0200b - U+0200f
255          U+030fc - U+030fe
256          U+03260 - U+0327f
257          U+0fb46 - U+0fbb1
258          U+10450 - U+1049d
260    12. The -o option (show only the matching part of a line) for pcregrep was not
261        compatible with GNU grep in that, if there was more than one match in a
262        line, it showed only the first of them. It now behaves in the same way as
263        GNU grep.
265    13. If the -o and -v options were combined for pcregrep, it printed a blank
266        line for every non-matching line. GNU grep prints nothing, and pcregrep now
267        does the same. The return code can be used to tell if there were any
268        non-matching lines.
270    14. Added --file-offsets and --line-offsets to pcregrep.
272    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
273        infinitely looping recursion. The bug was that positive lookaheads were not
274        being skipped when checking for a possible empty match (negative lookaheads
275        and both kinds of lookbehind were skipped).
277    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
278        inclusion of <windows.h> to before rather than after the definition of
279        INVALID_FILE_ATTRIBUTES (patch from David Byron).
281    17. Specifying a possessive quantifier with a specific limit for a Unicode
282        character property caused pcre_compile() to compile bad code, which led at
283        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
284        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
285        caused the error; without that there was no problem.
287    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
289    19. Added --enable-pcretest-libreadline.
291    20. In pcrecpp.cc, the variable 'count' was incremented twice in
292        RE::GlobalReplace(). As a result, the number of replacements returned was
293        double what it should be. I removed one of the increments, but Craig sent a
294        later patch that removed the other one (the right fix) and added unit tests
295        that check the return values (which was not done before).
297    21. Several CMake things:
299        (1) Arranged that, when cmake is used on Unix, the libraries end up with
300            the names libpcre and libpcreposix, not just pcre and pcreposix.
302        (2) The above change means that pcretest and pcregrep are now correctly
303            linked with the newly-built libraries, not previously installed ones.
307    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
308        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
309        UTF-8 newline character). The key issue is that the pattern starts .*;
310        this means that the match must be either at the beginning, or after a
311        newline. The bug was in the code for advancing after a failed match and
312        checking that the new position followed a newline. It was not taking
313        account of UTF-8 characters correctly.
315    23. PCRE was behaving differently from Perl in the way it recognized POSIX
316        character classes. PCRE was not treating the sequence [:...:] as a
317        character class unless the ... were all letters. Perl, however, seems to
318        allow any characters between [: and :], though of course it rejects as
319        unknown any "names" that contain non-letters, because all the known class
320        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
321        for example, whereas PCRE did not - it did not recognize a POSIX character
322        class. This seemed a bit dangerous, so the code has been changed to be
323        closer to Perl. The behaviour is not identical to Perl, because PCRE will
324        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
325        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
326        Perl does, and where it didn't before.
328    24. Rewrite so as to remove the single use of %n from pcregrep because in some
329        Windows environments %n is disabled by default.
332    Version 7.4 21-Sep-07
333    ---------------------
335    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
336        means that a class such as [\s] counted as "explicit reference to CR or
337        LF". That isn't really right - the whole point of the change was to try to
338        help when there was an actual mention of one of the two characters. So now
339        the change happens only if \r or \n (or a literal CR or LF) character is
340        encountered.
342    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
343        of both had grown to the point where there were only 3 bits left.
344        Fortunately, there was spare space in the data structure, and so I have
345        moved the internal flags into a new 16-bit field to free up more option
346        bits.
348    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
349        but did not set the internal JCHANGED flag - either of these is enough to
350        control the way the "get" function works - but the PCRE_INFO_JCHANGED
351        facility is supposed to tell if (?J) was ever used, so now (?J) at the
352        start sets both bits.
354    4.  Added options (at build time, compile time, exec time) to change \R from
355        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
357    5.  doc/pcresyntax.html was missing from the distribution.
359    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
360        compatibility, even though it is no longer used.
362    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
363        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
364        windows.h file is present (where different names are used). [This was
365        reversed later after testing - see 16 below.]
367    8.  Changed all #include <config.h> to #include "config.h". There were also
368        some further <pcre.h> cases that I changed to "pcre.h".
370    9.  When pcregrep was used with the --colour option, it missed the line ending
371        sequence off the lines that it output.
373    10. It was pointed out to me that arrays of string pointers cause lots of
374        relocations when a shared library is dynamically loaded. A technique of
375        using a single long string with a table of offsets can drastically reduce
376        these. I have refactored PCRE in four places to do this. The result is
377        dramatic:
379          Originally:                          290
380          After changing UCP table:            187
381          After changing error message table:   43
382          After changing table of "verbs"       36
383          After changing table of Posix names   22
385        Thanks to the folks working on Gregex for glib for this insight.
387    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
388        unicode-properties was also set.
390    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
392    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
393        checked only for CRLF.
395    14. Added casts to pcretest.c to avoid compiler warnings.
397    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
399    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
400        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
401        entirely. This removes changes made in 7 above.
403    17. The CMake files have been updated, and there is now more information about
404        building with CMake in the NON-UNIX-USE document.
407    Version 7.3 28-Aug-07
408    ---------------------
410     1. In the rejigging of the build system that eventually resulted in 7.1, the
411        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
412        brackets there is not right, since it causes compilers to look for an
413        installed pcre.h, not the version that is in the source that is being
414        compiled (which of course may be different). I have changed it back to:
416          #include "pcre.h"
418        I have a vague recollection that the change was concerned with compiling in
419        different directories, but in the new build system, that is taken care of
420        by the VPATH setting the Makefile.
422     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
423        when the subject happened to end in the byte 0x85 (e.g. if the last
424        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
425        characters but of course it shouldn't be taken as a newline when it is part
426        of another character. The bug was that, for an unlimited repeat of . in
427        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
428        characters when looking for a newline.
430     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
432     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
433        in debug output.
435     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
436        long printing in the pcrecpp unittest when running under MinGW.
438     6. ESC_K was left out of the EBCDIC table.
440     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
441        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
442        limit also applies to "virtual nesting" when a pattern is recursive, and in
443        this case 1000 isn't so big. I have been able to remove this limit at the
444        expense of backing off one optimization in certain circumstances. Normally,
445        when pcre_exec() would call its internal match() function recursively and
446        immediately return the result unconditionally, it uses a "tail recursion"
447        feature to save stack. However, when a subpattern that can match an empty
448        string has an unlimited repetition quantifier, it no longer makes this
449        optimization. That gives it a stack frame in which to save the data for
450        checking that an empty string has been matched. Previously this was taken
451        from the 1000-entry workspace that had been reserved. So now there is no
452        explicit limit, but more stack is used.
454     8. Applied Daniel's patches to solve problems with the import/export magic
455        syntax that is required for Windows, and which was going wrong for the
456        pcreposix and pcrecpp parts of the library. These were overlooked when this
457        problem was solved for the main library.
459     9. There were some crude static tests to avoid integer overflow when computing
460        the size of patterns that contain repeated groups with explicit upper
461        limits. As the maximum quantifier is 65535, the maximum group length was
462        set at 30,000 so that the product of these two numbers did not overflow a
463        32-bit integer. However, it turns out that people want to use groups that
464        are longer than 30,000 bytes (though not repeat them that many times).
465        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
466        made it possible to implement the integer overflow checks in a much more
467        dynamic way, which I have now done. The artificial limitation on group
468        length has been removed - we now have only the limit on the total length of
469        the compiled pattern, which depends on the LINK_SIZE setting.
471    10. Fixed a bug in the documentation for get/copy named substring when
472        duplicate names are permitted. If none of the named substrings are set, the
473        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
474        empty string.
476    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
477        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
478        because the ] is interpreted as the first data character and the
479        terminating ] is not found. PCRE has been made compatible with Perl in this
480        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
481        cause memory overwriting.
483    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
484        string has been matched (to stop an infinite loop). It was not recognizing
485        a conditional subpattern that could match an empty string if that
486        subpattern was within another subpattern. For example, it looped when
487        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
488        condition was not nested. This bug has been fixed.
490    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
491        past the start of the subject in the presence of bytes with the top bit
492        set, for example "\x8aBCD".
494    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
495        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
497    14. Optimized (?!) to (*FAIL).
499    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
500        This restricts code points to be within the range 0 to 0x10FFFF, excluding
501        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
502        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
503        does: it's just the validity check that is more restrictive.
505    16. Inserted checks for integer overflows during escape sequence (backslash)
506        processing, and also fixed erroneous offset values for syntax errors during
507        backslash processing.
509    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
510        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
512    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
513        caused an overrun.
515    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
516        something other than just ASCII characters) inside a group that had an
517        unlimited repeat caused a loop at compile time (while checking to see
518        whether the group could match an empty string).
520    20. Debugging a pattern containing \p or \P could cause a crash. For example,
521        [\P{Any}] did so. (Error in the code for printing property names.)
523    21. An orphan \E inside a character class could cause a crash.
525    22. A repeated capturing bracket such as (A)? could cause a wild memory
526        reference during compilation.
528    23. There are several functions in pcre_compile() that scan along a compiled
529        expression for various reasons (e.g. to see if it's fixed length for look
530        behind). There were bugs in these functions when a repeated \p or \P was
531        present in the pattern. These operators have additional parameters compared
532        with \d, etc, and these were not being taken into account when moving along
533        the compiled data. Specifically:
535        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
536            length.
538        (b) An item such as \pL+ within a repeated group could cause crashes or
539            loops.
541        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
542            "reference to non-existent subpattern" error.
544        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
546    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
547        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
549    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
551    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
552        character were causing crashes (broken optimization).
554    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
555        \p or \P) caused a compile-time loop.
557    28. More problems have arisen in unanchored patterns when CRLF is a valid line
558        break. For example, the unstudied pattern [\r\n]A does not match the string
559        "\r\nA" because change 7.0/46 below moves the current point on by two
560        characters after failing to match at the start. However, the pattern \nA
561        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
562        the same is true. There doesn't seem any very clean way out of this, but
563        what I have chosen to do makes the common cases work: PCRE now takes note
564        of whether there can be an explicit match for \r or \n anywhere in the
565        pattern, and if so, 7.0/46 no longer applies. As part of this change,
566        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
567        pattern has explicit CR or LF references.
569    29. Added (*CR) etc for changing newline setting at start of pattern.
572    Version 7.2 19-Jun-07
573    ---------------------
575     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
576        which is apparently normally available under Windows.
578     2. Re-jig the pcregrep tests with different newline settings in an attempt
579        to make them independent of the local environment's newline setting.
581     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
583     4. Some of the "internals" tests were previously cut out when the link size
584        was not 2, because the output contained actual offsets. The recent new
585        "Z" feature of pcretest means that these can be cut out, making the tests
586        usable with all link sizes.
588     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
589        stack recursion. This gives a massive performance boost under BSD, but just
590        a small improvement under Linux. However, it saves one field in the frame
591        in all cases.
593     6. Added more features from the forthcoming Perl 5.10:
595        (a) (?-n) (where n is a string of digits) is a relative subroutine or
596            recursion call. It refers to the nth most recently opened parentheses.
598        (b) (?+n) is also a relative subroutine call; it refers to the nth next
599            to be opened parentheses.
601        (c) Conditions that refer to capturing parentheses can be specified
602            relatively, for example, (?(-2)... or (?(+3)...
604        (d) \K resets the start of the current match so that everything before
605            is not part of it.
607        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
609        (f) \g{name} is another synonym - part of Perl 5.10's unification of
610            reference syntax.
612        (g) (?| introduces a group in which the numbering of parentheses in each
613            alternative starts with the same number.
615        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
617     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
620     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
621        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
622        for detecting groups that can match an empty string.
624     9. A pattern with a very large number of alternatives (more than several
625        hundred) was running out of internal workspace during the pre-compile
626        phase, where pcre_compile() figures out how much memory will be needed. A
627        bit of new cunning has reduced the workspace needed for groups with
628        alternatives. The 1000-alternative test pattern now uses 12 bytes of
629        workspace instead of running out of the 4096 that are available.
631    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
633    11. Applied patch from Google to remove an optimization that didn't quite work.
634        The report of the bug said:
636          pcrecpp::RE("a*").FullMatch("aaa") matches, while
637          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
638          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
640    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
641        it matched the wrong number of bytes.
644    Version 7.1 24-Apr-07
645    ---------------------
647     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
648        that is more "standard", making use of automake and other Autotools. There
649        is some re-arrangement of the files and adjustment of comments consequent
650        on this.
652     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
653        for recursive directory scanning broke on some systems because the files
654        are not scanned in any specific order and on different systems the order
655        was different. A call to "sort" has been inserted into RunGrepTest for the
656        approprate test as a short-term fix. In the longer term there may be an
657        alternative.
659     3. I had an email from Eric Raymond about problems translating some of PCRE's
660        man pages to HTML (despite the fact that I distribute HTML pages, some
661        people do their own conversions for various reasons). The problems
662        concerned the use of low-level troff macros .br and .in. I have therefore
663        removed all such uses from the man pages (some were redundant, some could
664        be replaced by .nf/.fi pairs). The 132html script that I use to generate
665        HTML has been updated to handle .nf/.fi and to complain if it encounters
666        .br or .in.
668     4. Updated comments in configure.ac that get placed in config.h.in and also
669        arranged for config.h to be included in the distribution, with the name
670        config.h.generic, for the benefit of those who have to compile without
671        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
673     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
674        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
675        makevp.bat for the current PCRE, using the additional files
676        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
678     6. A Windows user reported a minor discrepancy with test 2, which turned out
679        to be caused by a trailing space on an input line that had got lost in his
680        copy. The trailing space was an accident, so I've just removed it.
682     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
683        that is needed.
685     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
686        as "const" (a) because they are and (b) because it helps the PHP
687        maintainers who have recently made a script to detect big data structures
688        in the php code that should be moved to the .rodata section. I remembered
689        to update Builducptable as well, so it won't revert if ucptable.h is ever
690        re-created.
692     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
693        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
694        order to be able to cut out the UTF-8 tables in the latter when UTF-8
695        support is not required. This saves 1.5-2K of code, which is important in
696        some applications.
698        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
699        so as not to refer to the tables, even though these functions will never be
700        called when UTF-8 support is disabled. Otherwise there are problems with a
701        shared library.
703    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
705        (a) It was defining its arguments as char * instead of void *.
707        (b) It was assuming that all moves were upwards in memory; this was true
708            a long time ago when I wrote it, but is no longer the case.
710        The emulated memove() is provided for those environments that have neither
711        memmove() nor bcopy(). I didn't think anyone used it these days, but that
712        is clearly not the case, as these two bugs were recently reported.
714    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
715        and Detrail to create the HTML documentation, the .txt form of the man
716        pages, and it removes trailing spaces from listed files. It also creates
717        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
718        case, it wraps all the #defines with #ifndefs. This script should be run
719        before "make dist".
721    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
722        with Unicode property support.
724        (a) For a maximizing quantifier, if the two different cases of the
725            character were of different lengths in their UTF-8 codings (there are
726            some cases like this - I found 11), and the matching function had to
727            back up over a mixture of the two cases, it incorrectly assumed they
728            were both the same length.
730        (b) When PCRE was configured to use the heap rather than the stack for
731            recursion during matching, it was not correctly preserving the data for
732            the other case of a UTF-8 character when checking ahead for a match
733            while processing a minimizing repeat. If the check also involved
734            matching a wide character, but failed, corruption could cause an
735            erroneous result when trying to check for a repeat of the original
736            character.
738    13. Some tidying changes to the testing mechanism:
740        (a) The RunTest script now detects the internal link size and whether there
741            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
742            values substituted by "configure". (The RunGrepTest script already did
743            this for UTF-8.) The configure.ac script no longer substitutes the
744            relevant variables.
746        (b) The debugging options /B and /D in pcretest show the compiled bytecode
747            with length and offset values. This means that the output is different
748            for different internal link sizes. Test 2 is skipped for link sizes
749            other than 2 because of this, bypassing the problem. Unfortunately,
750            there was also a test in test 3 (the locale tests) that used /B and
751            failed for link sizes other than 2. Rather than cut the whole test out,
752            I have added a new /Z option to pcretest that replaces the length and
753            offset values with spaces. This is now used to make test 3 independent
754            of link size. (Test 2 will be tidied up later.)
756    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
757        segmentation fault instead of returning the appropriate error message.
759    15. In multiline mode when the newline sequence was set to "any", the pattern
760        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
761        This doesn't seem right; it now treats the CRLF combination as the line
762        ending, and so does not match in that case. It's only a pattern such as ^$
763        that would hit this one: something like ^ABC$ would have failed after \r
764        and then tried again after \r\n.
766    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
767        in an attempt to make files that differ only in their line terminators
768        compare equal. This works on Linux.
770    17. Under certain error circumstances pcregrep might try to free random memory
771        as it exited. This is now fixed, thanks to valgrind.
773    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
774        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
775        was because its rules for how to advance for /g after matching an empty
776        string at the end of a line did not allow for this case. They now check for
777        it specially.
779    20. pcretest is supposed to handle patterns and data of any length, by
780        extending its buffers when necessary. It was getting this wrong when the
781        buffer for a data line had to be extended.
783    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
784        CRLF as a newline sequence.
786    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
787        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
788        I have nevertheless tidied it up.
790    23. Added some casts to kill warnings from HP-UX ia64 compiler.
792    24. Added a man page for pcre-config.
795    Version 7.0 19-Dec-06
796    ---------------------
798     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
799        moving to gcc 4.1.1.
801     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
802        sys/time.h, which is documented as needed for this function. It doesn't
803        seem to matter on Linux, but it showed up on some releases of OS X.
805     3. It seems that there are systems where bytes whose values are greater than
806        127 match isprint() in the "C" locale. The "C" locale should be the
807        default when a C program starts up. In most systems, only ASCII printing
808        characters match isprint(). This difference caused the output from pcretest
809        to vary, making some of the tests fail. I have changed pcretest so that:
811        (a) When it is outputting text in the compiled version of a pattern, bytes
812            other than 32-126 are always shown as hex escapes.
814        (b) When it is outputting text that is a matched part of a subject string,
815            it does the same, unless a different locale has been set for the match
816            (using the /L modifier). In this case, it uses isprint() to decide.
818     4. Fixed a major bug that caused incorrect computation of the amount of memory
819        required for a compiled pattern when options that changed within the
820        pattern affected the logic of the preliminary scan that determines the
821        length. The relevant options are -x, and -i in UTF-8 mode. The result was
822        that the computed length was too small. The symptoms of this bug were
823        either the PCRE error "internal error: code overflow" from pcre_compile(),
824        or a glibc crash with a message such as "pcretest: free(): invalid next
825        size (fast)". Examples of patterns that provoked this bug (shown in
826        pcretest format) are:
828          /(?-x: )/x
829          /(?x)(?-x: \s*#\s*)/
830          /((?i)[\x{c0}])/8
831          /(?i:[\x{c0}])/8
833        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
834        is now done differently.
836     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
837        wrapper classes; (b) implement a new function in the C++ scanner that is
838        more efficient than the old way of doing things because it avoids levels of
839        recursion in the regex matching; (c) add a paragraph to the documentation
840        for the FullMatch() function.
842     6. The escape sequence \n was being treated as whatever was defined as
843        "newline". Not only was this contrary to the documentation, which states
844        that \n is character 10 (hex 0A), but it also went horribly wrong when
845        "newline" was defined as CRLF. This has been fixed.
847     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
848        was being set to -1 for the "end of line" case (supposedly a value that no
849        character can have). Though this value is never used (the check for end of
850        line is "zero bytes in current character"), it caused compiler complaints.
851        I've changed it to 0xffffffff.
853     8. In pcre_version.c, the version string was being built by a sequence of
854        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
855        string (as it is for production releases) called a macro with an empty
856        argument. The C standard says the result of this is undefined. The gcc
857        compiler treats it as an empty string (which was what was wanted) but it is
858        reported that Visual C gives an error. The source has been hacked around to
859        avoid this problem.
861     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
862        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
863        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
864        of them did).
866    10. Originally, pcretest opened its input and output without "b"; then I was
867        told that "b" was needed in some environments, so it was added for release
868        5.0 to both the input and output. (It makes no difference on Unix-like
869        systems.) Later I was told that it is wrong for the input on Windows. I've
870        now abstracted the modes into two macros, to make it easier to fiddle with
871        them, and removed "b" from the input mode under Windows.
873    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
875    12. Added -help and --help to pcretest as an official way of being reminded
876        of the options.
878    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
879        and pcrecpp.cc because they annoy compilers at high warning levels.
881    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
883    15. Fixed an occurrence of == in configure.ac that should have been = (shell
884        scripts are not C programs :-) and which was not noticed because it works
885        on Linux.
887    16. pcretest is supposed to handle any length of pattern and data line (as one
888        line or as a continued sequence of lines) by extending its input buffer if
889        necessary. This feature was broken for very long pattern lines, leading to
890        a string of junk being passed to pcre_compile() if the pattern was longer
891        than about 50K.
893    17. I have done a major re-factoring of the way pcre_compile() computes the
894        amount of memory needed for a compiled pattern. Previously, there was code
895        that made a preliminary scan of the pattern in order to do this. That was
896        OK when PCRE was new, but as the facilities have expanded, it has become
897        harder and harder to keep it in step with the real compile phase, and there
898        have been a number of bugs (see for example, 4 above). I have now found a
899        cunning way of running the real compile function in a "fake" mode that
900        enables it to compute how much memory it would need, while actually only
901        ever using a few hundred bytes of working memory and without too many
902        tests of the mode. This should make future maintenance and development
903        easier. A side effect of this work is that the limit of 200 on the nesting
904        depth of parentheses has been removed (though this was never a serious
905        limitation, I suspect). However, there is a downside: pcre_compile() now
906        runs more slowly than before (30% or more, depending on the pattern). I
907        hope this isn't a big issue. There is no effect on runtime performance.
909    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
910        newline (only possible for the last line of a file) and it was a
911        pattern that set a locale (followed by /Lsomething), pcretest crashed.
913    19. Added additional timing features to pcretest. (1) The -tm option now times
914        matching only, not compiling. (2) Both -t and -tm can be followed, as a
915        separate command line item, by a number that specifies the number of
916        repeats to use when timing. The default is 50000; this gives better
917        precision, but takes uncomfortably long for very large patterns.
919    20. Extended pcre_study() to be more clever in cases where a branch of a
920        subpattern has no definite first character. For example, (a*|b*)[cd] would
921        previously give no result from pcre_study(). Now it recognizes that the
922        first character must be a, b, c, or d.
924    21. There was an incorrect error "recursive call could loop indefinitely" if
925        a subpattern (or the entire pattern) that was being tested for matching an
926        empty string contained only one non-empty item after a nested subpattern.
927        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
928        incorrectly, because the \d was being skipped in the check.
930    22. The pcretest program now has a new pattern option /B and a command line
931        option -b, which is equivalent to adding /B to every pattern. This causes
932        it to show the compiled bytecode, without the additional information that
933        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
934        is the same as /B/I).
936    23. A new optimization is now able automatically to treat some sequences such
937        as a*b as a*+b. More specifically, if something simple (such as a character
938        or a simple class like \d) has an unlimited quantifier, and is followed by
939        something that cannot possibly match the quantified thing, the quantifier
940        is automatically "possessified".
942    24. A recursive reference to a subpattern whose number was greater than 39
943        went wrong under certain circumstances in UTF-8 mode. This bug could also
944        have affected the operation of pcre_study().
946    25. Realized that a little bit of performance could be had by replacing
947        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
949    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
951    27. Possessive quantifiers such as a++ were previously implemented by turning
952        them into atomic groups such as ($>a+). Now they have their own opcodes,
953        which improves performance. This includes the automatically created ones
954        from 23 above.
956    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
957        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
958        the first matched character to be a colon. This applied both to named and
959        numbered groups.
961    29. The ucpinternal.h header file was missing its idempotency #ifdef.
963    30. I was sent a "project" file called libpcre.a.dev which I understand makes
964        building PCRE on Windows easier, so I have included it in the distribution.
966    31. There is now a check in pcretest against a ridiculously large number being
967        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
968        loop, the loop is abandoned.
970    32. Forward references to subpatterns in conditions such as (?(2)...) where
971        subpattern 2 is defined later cause pcre_compile() to search forwards in
972        the pattern for the relevant set of parentheses. This search went wrong
973        when there were unescaped parentheses in a character class, parentheses
974        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
976    33. "Subroutine" calls and backreferences were previously restricted to
977        referencing subpatterns earlier in the regex. This restriction has now
978        been removed.
980    34. Added a number of extra features that are going to be in Perl 5.10. On the
981        whole, these are just syntactic alternatives for features that PCRE had
982        previously implemented using the Python syntax or my own invention. The
983        other formats are all retained for compatibility.
985        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
986            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
987            also .NET compatible.
989        (b) A recursion or subroutine call to a named group can now be defined as
990            (?&name) as well as (?P>name).
992        (c) A backreference to a named group can now be defined as \k<name> or
993            \k'name' as well as (?P=name). The new forms, as well as being in Perl
994            5.10, are also .NET compatible.
996        (d) A conditional reference to a named group can now use the syntax
997            (?(<name>) or (?('name') as well as (?(name).
999        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1000            groups (named and numbered) that are never evaluated inline, but can be
1001            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1002            is always false. There may be only one alternative in such a group.
1004        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1005            as the simple (?(R). The condition is true only if the most recent
1006            recursion is that of the given number or name. It does not search out
1007            through the entire recursion stack.
1009        (g) The escape \gN or \g{N} has been added, where N is a positive or
1010            negative number, specifying an absolute or relative reference.
1012    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1013        some "unreachable code" warnings.
1015    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1016        things, this adds five new scripts.
1018    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1019        There were also incompatibilities regarding the handling of \Q..\E inside
1020        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1021        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1023    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1024        matches an empty string, and forcibly breaks the loop. There were bugs in
1025        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1026        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1027        separate and independent bugs (that affected different cases) have been
1028        fixed.
1030    39. Refactored the code to abolish the use of different opcodes for small
1031        capturing bracket numbers. This is a tidy that I avoided doing when I
1032        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1033        The new approach is not only tidier, it makes it possible to reduce the
1034        memory needed to fix the previous bug (38).
1036    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1037        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1038        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1039        mode.
1041    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1042        report.
1044    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1045        copy construction and assignment in the C++ wrapper.
1047    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1048        couple of bugs that could have given wrong results in the "--newline=crlf"
1049        case.
1051    44. Added a number of casts and did some reorganization of signed/unsigned int
1052        variables following suggestions from Dair Grant. Also renamed the variable
1053        "this" as "item" because it is a C++ keyword.
1055    45. Arranged for dftables to add
1057          #include "pcre_internal.h"
1059        to pcre_chartables.c because without it, gcc 4.x may remove the array
1060        definition from the final binary if PCRE is built into a static library and
1061        dead code stripping is activated.
1063    46. For an unanchored pattern, if a match attempt fails at the start of a
1064        newline sequence, and the newline setting is CRLF or ANY, and the next two
1065        characters are CRLF, advance by two characters instead of one.
1068    Version 6.7 04-Jul-06
1069    ---------------------
1071     1. In order to handle tests when input lines are enormously long, pcretest has
1072        been re-factored so that it automatically extends its buffers when
1073        necessary. The code is crude, but this _is_ just a test program. The
1074        default size has been increased from 32K to 50K.
1076     2. The code in pcre_study() was using the value of the re argument before
1077        testing it for NULL. (Of course, in any sensible call of the function, it
1078        won't be NULL.)
1080     3. The memmove() emulation function in pcre_internal.h, which is used on
1081        systems that lack both memmove() and bcopy() - that is, hardly ever -
1082        was missing a "static" storage class specifier.
1084     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1085        containing an extended class (one that cannot be represented by a bitmap
1086        because it contains high-valued characters or Unicode property items, e.g.
1087        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1088        pattern, but PCRE should not loop if you do not (it no longer does).
1089        [Detail: two cases were found: (a) a repeated subpattern containing an
1090        extended class; (b) a recursive reference to a subpattern that followed a
1091        previous extended class. It wasn't skipping over the extended class
1092        correctly when UTF-8 mode was not set.]
1094     5. A negated single-character class was not being recognized as fixed-length
1095        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1096        compile error "lookbehind assertion is not fixed length".
1098     6. The RunPerlTest auxiliary script was showing an unexpected difference
1099        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1100        write a Perl script that can interpret lines of an input file either as
1101        byte characters or as UTF-8, which is what "perltest" was being required to
1102        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1103        can't do is switch easily at run time between having the "use utf8;" pragma
1104        or not. In the end, I fudged it by using the RunPerlTest script to insert
1105        "use utf8;" explicitly for the UTF-8 tests.
1107     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1108        the end of the subject string, contrary to the documentation and to what
1109        Perl does. This was true of both matching functions. Now it matches only at
1110        the start of the subject and immediately after *internal* newlines.
1112     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1113        a pointer to an int instead of a pointer to an unsigned long int. This
1114        caused problems on 64-bit systems.
1116     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1117        instance of the 'standard' template library not being so standard".
1119    10. There was no check on the number of named subpatterns nor the maximum
1120        length of a subpattern name. The product of these values is used to compute
1121        the size of the memory block for a compiled pattern. By supplying a very
1122        long subpattern name and a large number of named subpatterns, the size
1123        computation could be caused to overflow. This is now prevented by limiting
1124        the length of names to 32 characters, and the number of named subpatterns
1125        to 10,000.
1127    11. Subpatterns that are repeated with specific counts have to be replicated in
1128        the compiled pattern. The size of memory for this was computed from the
1129        length of the subpattern and the repeat count. The latter is limited to
1130        65535, but there was no limit on the former, meaning that integer overflow
1131        could in principle occur. The compiled length of a repeated subpattern is
1132        now limited to 30,000 bytes in order to prevent this.
1134    12. Added the optional facility to have named substrings with the same name.
1136    13. Added the ability to use a named substring as a condition, using the
1137        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1138        are numbers (not recommended). Forward references are permitted.
1140    14. Added forward references in named backreferences (if you see what I mean).
1142    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1143        pattern could run off the end of the subject. For example, the pattern
1144        "(?s)(.{1,5})"8 did this with the subject "ab".
1146    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1147        PCRE_CASELESS was set when matching characters that were quantified with ?
1148        or *.
1150    17. A character class other than a single negated character that had a minimum
1151        but no maximum quantifier - for example [ab]{6,} - was not handled
1152        correctly by pce_dfa_exec(). It would match only one character.
1154    18. A valid (though odd) pattern that looked like a POSIX character
1155        class but used an invalid character after [ (for example [[,abc,]]) caused
1156        pcre_compile() to give the error "Failed: internal error: code overflow" or
1157        in some cases to crash with a glibc free() error. This could even happen if
1158        the pattern terminated after [[ but there just happened to be a sequence of
1159        letters, a binary zero, and a closing ] in the memory that followed.
1161    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1162        over the years. Originally (before any Unicode support), just the bottom 8
1163        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1164        output from "man perlunicode" includes this:
1166          The regular expression compiler produces polymorphic opcodes.  That
1167          is, the pattern adapts to the data and automatically switches to
1168          the Unicode character scheme when presented with Unicode data--or
1169          instead uses a traditional byte scheme when presented with byte
1170          data.
1172        Sadly, a wide octal escape does not cause a switch, and in a string with
1173        no other multibyte characters, these octal escapes are treated as before.
1174        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1175        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1176        Unicode string.
1178        I have not perpetrated such confusion in PCRE. Up till now, it took just
1179        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1180        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1181        translate to the appropriate multibyte character.
1183    29. Applied some refactoring to reduce the number of warnings from Microsoft
1184        and Borland compilers. This has included removing the fudge introduced
1185        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1186        a warning about an unused variable.
1188    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1189        characters since release 4.0, because Perl (from release 5.004) does not.
1190        [Or at least, is documented not to: some releases seem to be in conflict
1191        with the documentation.] However, when a pattern was studied with
1192        pcre_study() and all its branches started with \s, PCRE still included VT
1193        as a possible starting character. Of course, this did no harm; it just
1194        caused an unnecessary match attempt.
1196    22. Removed a now-redundant internal flag bit that recorded the fact that case
1197        dependency changed within the pattern. This was once needed for "required
1198        byte" processing, but is no longer used. This recovers a now-scarce options
1199        bit. Also moved the least significant internal flag bit to the most-
1200        significant bit of the word, which was not previously used (hangover from
1201        the days when it was an int rather than a uint) to free up another bit for
1202        the future.
1204    23. Added support for CRLF line endings as well as CR and LF. As well as the
1205        default being selectable at build time, it can now be changed at runtime
1206        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1207        specify that it is scanning data with non-default line endings.
1209    24. Changed the definition of CXXLINK to make it agree with the definition of
1210        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1212    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1213        recursions. This makes a big different to stack usage for some patterns.
1215    26. If a subpattern containing a named recursion or subroutine reference such
1216        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1217        the space required for the compiled pattern went wrong and gave too small a
1218        value. Depending on the environment, this could lead to "Failed: internal
1219        error: code overflow at offset 49" or "glibc detected double free or
1220        corruption" errors.
1222    27. Applied patches from Google (a) to support the new newline modes and (b) to
1223        advance over multibyte UTF-8 characters in GlobalReplace.
1225    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1226        difference for some implementation of PCRE in some Windows version.
1228    29. Added some extra testing facilities to pcretest:
1230        \q<number>   in a data line sets the "match limit" value
1231        \Q<number>   in a data line sets the "match recursion limt" value
1232        -S <number>  sets the stack size, where <number> is in megabytes
1234        The -S option isn't available for Windows.
1237    Version 6.6 06-Feb-06
1238    ---------------------
1240     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1241        in pcreposix.h. I have copied the definition from pcre.h.
1243     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1244        because pcre.h is no longer a built file.
1246     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1247        not normally included in the compiled code.
1250    Version 6.5 01-Feb-06
1251    ---------------------
1253     1. When using the partial match feature with pcre_dfa_exec(), it was not
1254        anchoring the second and subsequent partial matches at the new starting
1255        point. This could lead to incorrect results. For example, with the pattern
1256        /1234/, partially matching against "123" and then "a4" gave a match.
1258     2. Changes to pcregrep:
1260        (a) All non-match returns from pcre_exec() were being treated as failures
1261            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1262            error message is output. Some extra information is given for the
1263            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1264            probably the only errors that are likely to be caused by users (by
1265            specifying a regex that has nested indefinite repeats, for instance).
1266            If there are more than 20 of these errors, pcregrep is abandoned.
1268        (b) A binary zero was treated as data while matching, but terminated the
1269            output line if it was written out. This has been fixed: binary zeroes
1270            are now no different to any other data bytes.
1272        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1273            used to set a locale for matching. The --locale=xxxx long option has
1274            been added (no short equivalent) to specify a locale explicitly on the
1275            pcregrep command, overriding the environment variables.
1277        (d) When -B was used with -n, some line numbers in the output were one less
1278            than they should have been.
1280        (e) Added the -o (--only-matching) option.
1282        (f) If -A or -C was used with -c (count only), some lines of context were
1283            accidentally printed for the final match.
1285        (g) Added the -H (--with-filename) option.
1287        (h) The combination of options -rh failed to suppress file names for files
1288            that were found from directory arguments.
1290        (i) Added the -D (--devices) and -d (--directories) options.
1292        (j) Added the -F (--fixed-strings) option.
1294        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1296        (l) Added the --colo(u)r option.
1298        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1299            is not present by default.
1301     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1302        items such as (?R) or (?1), when the recursion could match a number of
1303        alternatives. If it matched one of the alternatives, but subsequently,
1304        outside the recursion, there was a failure, the code tried to back up into
1305        the recursion. However, because of the way PCRE is implemented, this is not
1306        possible, and the result was an incorrect result from the match.
1308        In order to prevent this happening, the specification of recursion has
1309        been changed so that all such subpatterns are automatically treated as
1310        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1312     4. I had overlooked the fact that, in some locales, there are characters for
1313        which isalpha() is true but neither isupper() nor islower() are true. In
1314        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1315        and ordfeminine) are like this. This affected the treatment of \w and \W
1316        when they appeared in character classes, but not when they appeared outside
1317        a character class. The bit map for "word" characters is now created
1318        separately from the results of isalnum() instead of just taking it from the
1319        upper, lower, and digit maps. (Plus the underscore character, of course.)
1321     5. The above bug also affected the handling of POSIX character classes such as
1322        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1323        permanent tables. Instead, the bit maps for such a class were previously
1324        created as the appropriate unions of the upper, lower, and digit bitmaps.
1325        Now they are created by subtraction from the [[:word:]] class, which has
1326        its own bitmap.
1328     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1329        It is created by subtracting the vertical space characters (\x09, \x0a,
1330        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1331        subtraction was done in the overall bitmap for a character class, meaning
1332        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1333        be recognized. This bug has been fixed.
1335     7. Patches from the folks at Google:
1337          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1338          real life, but is still worth protecting against".
1340          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1341          regular expressions".
1343          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1344          have it.
1346          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1347          "configure" and the latter not, in order to fix a problem somebody had
1348          with compiling the Arg class on HP-UX.
1350          (e) Improve the error-handling of the C++ wrapper a little bit.
1352          (f) New tests for checking recursion limiting.
1354     8. The pcre_memmove() function, which is used only if the environment does not
1355        have a standard memmove() function (and is therefore rarely compiled),
1356        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1357        returning a result (though PCRE never actually uses the result).
1359     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1360        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1361        returned instead of calling malloc() with an overflowing number that would
1362        most likely cause subsequent chaos.
1364    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1366    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1367        with this option is matched, the nmatch and pmatch options of regexec() are
1368        ignored.
1370    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1371        provided in case anyone wants to the the POSIX interface with UTF-8
1372        strings.
1374    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1375        C++ linking (needed for some HP-UX environments).
1377    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1378        (unused parameter) and in the pcre_printint() function (omitted "default"
1379        switch label when the default is to do nothing).
1381    15. Added some code to make it possible, when PCRE is compiled as a C++
1382        library, to replace subject pointers for pcre_exec() with a smart pointer
1383        class, thus making it possible to process discontinuous strings.
1385    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1386        much the same function. They were added by different people who were trying
1387        to make PCRE easy to compile on non-Unix systems. It has been suggested
1388        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1389        for compiling on Windows systems. I have therefore replaced it with
1390        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1391        defaults to "extern" for C or "extern C" for C++, which works fine on
1392        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1393        SCOPE with something explicit in config.h. In addition:
1395        (a) pcreposix.h still had just "extern" instead of either of these macros;
1396            I have replaced it with PCRE_DATA_SCOPE.
1398        (b) Functions such as _pcre_xclass(), which are internal to the library,
1399            but external in the C sense, all had PCRE_EXPORT in their definitions.
1400            This is apparently wrong for the Windows case, so I have removed it.
1401            (It makes no difference on Unix-like systems.)
1403    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1404        of recursive calls to match(). This is different to MATCH_LIMIT because
1405        that limits the total number of calls to match(), not all of which increase
1406        the depth of recursion. Limiting the recursion depth limits the amount of
1407        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1408        when PCRE is compiled, and changed at run time. A patch from Google adds
1409        this functionality to the C++ interface.
1411    18. Changes to the handling of Unicode character properties:
1413        (a) Updated the table to Unicode 4.1.0.
1415        (b) Recognize characters that are not in the table as "Cn" (undefined).
1417        (c) I revised the way the table is implemented to a much improved format
1418            which includes recognition of ranges. It now supports the ranges that
1419            are defined in UnicodeData.txt, and it also amalgamates other
1420            characters into ranges. This has reduced the number of entries in the
1421            table from around 16,000 to around 3,000, thus reducing its size
1422            considerably. I realized I did not need to use a tree structure after
1423            all - a binary chop search is just as efficient. Having reduced the
1424            number of entries, I extended their size from 6 bytes to 8 bytes to
1425            allow for more data.
1427        (d) Added support for Unicode script names via properties such as \p{Han}.
1429    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1430        matching that character.
1432    20. When matching a repeated Unicode property with a minimum greater than zero,
1433        (for example \pL{2,}), PCRE could look past the end of the subject if it
1434        reached it while seeking the minimum number of characters. This could
1435        happen only if some of the characters were more than one byte long, because
1436        there is a check for at least the minimum number of bytes.
1438    21. Refactored the implementation of \p and \P so as to be more general, to
1439        allow for more different types of property in future. This has changed the
1440        compiled form incompatibly. Anybody with saved compiled patterns that use
1441        \p or \P will have to recompile them.
1443    22. Added "Any" and "L&" to the supported property types.
1445    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1446        but give a compile time error if the value is greater than 0xff.
1448    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1449        accidentally not being installed or uninstalled.
1451    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1452        made were to insert the current release number. This seemed silly, because
1453        it made things harder for people building PCRE on systems that don't run
1454        "configure". I have turned pcre.h into a distributed file, no longer built
1455        by "configure", with the version identification directly included. There is
1456        no longer a pcre.h.in file.
1458        However, this change necessitated a change to the pcre-config script as
1459        well. It is built from pcre-config.in, and one of the substitutions was the
1460        release number. I have updated configure.ac so that ./configure now finds
1461        the release number by grepping pcre.h.
1463    26. Added the ability to run the tests under valgrind.
1466    Version 6.4 05-Sep-05
1467    ---------------------
1469     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1470        "--" to be printed when multiple files were scanned, even when none of the
1471        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1472        consider it to be a bug, and have restored the previous behaviour.
1474     2. A couple of code tidies to get rid of compiler warnings.
1476     3. The pcretest program used to cheat by referring to symbols in the library
1477        whose names begin with _pcre_. These are internal symbols that are not
1478        really supposed to be visible externally, and in some environments it is
1479        possible to suppress them. The cheating is now confined to including
1480        certain files from the library's source, which is a bit cleaner.
1482     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1483        file's purpose clearer.
1485     5. Reorganized pcre_ucp_findchar().
1488    Version 6.3 15-Aug-05
1489    ---------------------
1491     1. The file libpcre.pc.in did not have general read permission in the tarball.
1493     2. There were some problems when building without C++ support:
1495        (a) If C++ support was not built, "make install" and "make test" still
1496            tried to test it.
1498        (b) There were problems when the value of CXX was explicitly set. Some
1499            changes have been made to try to fix these, and ...
1501        (c) --disable-cpp can now be used to explicitly disable C++ support.
1503        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1504            backslash in a target when C++ was disabled. This confuses some
1505            versions of "make", apparently. Using an intermediate variable solves
1506            this. (Same for CPP_LOBJ.)
1508     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1509        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1510        necessary on certain architectures.
1512     4. Added a setting of -export-symbols-regex to the link command to remove
1513        those symbols that are exported in the C sense, but actually are local
1514        within the library, and not documented. Their names all begin with
1515        "_pcre_". This is not a perfect job, because (a) we have to except some
1516        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1517        available (and never for static libraries). I have made a note to try to
1518        find a way round (a) in the future.
1521    Version 6.2 01-Aug-05
1522    ---------------------
1524     1. There was no test for integer overflow of quantifier values. A construction
1525        such as {1111111111111111} would give undefined results. What is worse, if
1526        a minimum quantifier for a parenthesized subpattern overflowed and became
1527        negative, the calculation of the memory size went wrong. This could have
1528        led to memory overwriting.
1530     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1532     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1533        operating environments where this matters.
1535     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1536        PCRE options from within the C++ wrapper.
1538     5. Named capturing subpatterns were not being correctly counted when a pattern
1539        was compiled. This caused two problems: (a) If there were more than 100
1540        such subpatterns, the calculation of the memory needed for the whole
1541        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1542        back references of the form \12, where the number was greater than 9, were
1543        not recognized as back references, even though there were sufficient
1544        previous subpatterns.
1546     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1547        versions of gcc, e.g. 2.95.4.
1550    Version 6.1 21-Jun-05
1551    ---------------------
1553     1. There was one reference to the variable "posix" in pcretest.c that was not
1554        surrounded by "#if !defined NOPOSIX".
1556     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1557        the cross-check on the old pcre_info() function, for the benefit of the
1558        cut-down version of PCRE that is currently imported into Exim.
1560     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1561        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1562        patterns that start (?i) but I don't think that matters. The use of (?i) is
1563        just an example; this all applies to the other options as well.
1565     4. Since libtool seems to echo the compile commands it is issuing, the output
1566        from "make" can be reduced a bit by putting "@" in front of each libtool
1567        compile command.
1569     5. Patch from the folks at Google for configure.in to be a bit more thorough
1570        in checking for a suitable C++ installation before trying to compile the
1571        C++ stuff. This should fix a reported problem when a compiler was present,
1572        but no suitable headers.
1574     6. The man pages all had just "PCRE" as their title. I have changed them to
1575        be the relevant file name. I have also arranged that these names are
1576        retained in the file doc/pcre.txt, which is a concatenation in text format
1577        of all the man pages except the little individual ones for each function.
1579     7. The NON-UNIX-USE file had not been updated for the different set of source
1580        files that come with release 6. I also added a few comments about the C++
1581        wrapper.
1584    Version 6.0 07-Jun-05
1585    ---------------------
1587     1. Some minor internal re-organization to help with my DFA experiments.
1589     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1590        didn't matter for the library itself when fully configured, but did matter
1591        when compiling without UCP support, or within Exim, where the ucp files are
1592        not imported.
1594     3. Refactoring of the library code to split up the various functions into
1595        different source modules. The addition of the new DFA matching code (see
1596        below) to a single monolithic source would have made it really too
1597        unwieldy, quite apart from causing all the code to be include in a
1598        statically linked application, when only some functions are used. This is
1599        relevant even without the DFA addition now that patterns can be compiled in
1600        one application and matched in another.
1602        The downside of splitting up is that there have to be some external
1603        functions and data tables that are used internally in different modules of
1604        the library but which are not part of the API. These have all had their
1605        names changed to start with "_pcre_" so that they are unlikely to clash
1606        with other external names.
1608     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1609        a different (DFA) algorithm. Although it is slower than the original
1610        function, it does have some advantages for certain types of matching
1611        problem.
1613     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1614        including restarting after a partial match.
1616     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1617        defined when compiling for Windows was sent to me. I have put it into the
1618        code, though I have no means of testing or verifying it.
1620     7. Added the pcre_refcount() auxiliary function.
1622     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1623        match before or at the first newline in the subject string. In pcretest,
1624        the /f option on a pattern can be used to set this.
1626     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1627        would behave wrongly. This has been present in PCRE since release 4.0.
1629    10. A number of changes to the pcregrep command:
1631        (a) Refactored how -x works; insert ^(...)$ instead of setting
1632            PCRE_ANCHORED and checking the length, in preparation for adding
1633            something similar for -w.
1635        (b) Added the -w (match as a word) option.
1637        (c) Refactored the way lines are read and buffered so as to have more
1638            than one at a time available.
1640        (d) Implemented a pcregrep test script.
1642        (e) Added the -M (multiline match) option. This allows patterns to match
1643            over several lines of the subject. The buffering ensures that at least
1644            8K, or the rest of the document (whichever is the shorter) is available
1645            for matching (and similarly the previous 8K for lookbehind assertions).
1647        (f) Changed the --help output so that it now says
1649              -w, --word-regex(p)
1651            instead of two lines, one with "regex" and the other with "regexp"
1652            because that confused at least one person since the short forms are the
1653            same. (This required a bit of code, as the output is generated
1654            automatically from a table. It wasn't just a text change.)
1656        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1657            option but starts with a hyphen. Could be a pattern or a path name
1658            starting with a hyphen, for instance.
1660        (h) "-" can be given as a file name to represent stdin.
1662        (i) When file names are being printed, "(standard input)" is used for
1663            the standard input, for compatibility with GNU grep. Previously
1664            "<stdin>" was used.
1666        (j) The option --label=xxx can be used to supply a name to be used for
1667            stdin when file names are being printed. There is no short form.
1669        (k) Re-factored the options decoding logic because we are going to add
1670            two more options that take data. Such options can now be given in four
1671            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1673        (l) Added the -A, -B, and -C options for requesting that lines of context
1674            around matches be printed.
1676        (m) Added the -L option to print the names of files that do not contain
1677            any matching lines, that is, the complement of -l.
1679        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1680            continue to scan other files.
1682        (o) The -s option was incorrectly implemented. For compatibility with other
1683            greps, it now suppresses the error message for a non-existent or non-
1684            accessible file (but not the return code). There is a new option called
1685            -q that suppresses the output of matching lines, which was what -s was
1686            previously doing.
1688        (p) Added --include and --exclude options to specify files for inclusion
1689            and exclusion when recursing.
1691    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1692        Hopefully, it now does.
1694    12. Missing cast in pcre_study().
1696    13. Added an "uninstall" target to the makefile.
1698    14. Replaced "extern" in the function prototypes in Makefile.in with
1699        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1700        world, but is set differently for Windows.
1702    15. Added a second compiling function called pcre_compile2(). The only
1703        difference is that it has an extra argument, which is a pointer to an
1704        integer error code. When there is a compile-time failure, this is set
1705        non-zero, in addition to the error test pointer being set to point to an
1706        error message. The new argument may be NULL if no error number is required
1707        (but then you may as well call pcre_compile(), which is now just a
1708        wrapper). This facility is provided because some applications need a
1709        numeric error indication, but it has also enabled me to tidy up the way
1710        compile-time errors are handled in the POSIX wrapper.
1712    16. Added VPATH=.libs to the makefile; this should help when building with one
1713        prefix path and installing with another. (Or so I'm told by someone who
1714        knows more about this stuff than I do.)
1716    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1717        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1718        match everything, including newlines. This is not POSIX-compatible, but
1719        somebody wanted the feature. From pcretest it can be activated by using
1720        both the P and the s flags.
1722    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1724    19. libpcre.pc was being incorrectly installed as executable.
1726    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1727        it now also looks for '\r' so that it will work unmodified on Windows.
1729    21. Added Google's contributed C++ wrapper to the distribution.
1731    22. Added some untidy missing memory free() calls in pcretest, to keep
1732        Electric Fence happy when testing.
1736    Version 5.0 13-Sep-04
1737    ---------------------
1739     1. Internal change: literal characters are no longer packed up into items
1740        containing multiple characters in a single byte-string. Each character
1741        is now matched using a separate opcode. However, there may be more than one
1742        byte in the character in UTF-8 mode.
1744     2. The pcre_callout_block structure has two new fields: pattern_position and
1745        next_item_length. These contain the offset in the pattern to the next match
1746        item, and its length, respectively.
1748     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1749        insertion of callouts before each pattern item. Added the /C option to
1750        pcretest to make use of this.
1752     4. On the advice of a Windows user, the lines
1754          #if defined(_WIN32) || defined(WIN32)
1755          _setmode( _fileno( stdout ), 0x8000 );
1756          #endif  /* defined(_WIN32) || defined(WIN32) */
1758        have been added to the source of pcretest. This apparently does useful
1759        magic in relation to line terminators.
1761     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1762        for the benefit of those environments where the "b" makes a difference.
1764     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1765        to know about it. I have put a hack into configure.in that adds in code
1766        to set GCC=yes if CC=icc. This seems to end up at a point in the
1767        generated configure script that is early enough to affect the setting of
1768        compiler options, which is what is needed, but I have no means of testing
1769        whether it really works. (The user who reported this had patched the
1770        generated configure script, which of course I cannot do.)
1772        LATER: After change 22 below (new libtool files), the configure script
1773        seems to know about icc (and also ecc). Therefore, I have commented out
1774        this hack in configure.in.
1776     7. Added support for pkg-config (2 patches were sent in).
1778     8. Negated POSIX character classes that used a combination of internal tables
1779        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1780        [[:^ascii]]. Typically, they would match almost any characters. The other
1781        POSIX classes were not broken in this way.
1783     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1784        to find the match, as PCRE was deluded into thinking that the match had to
1785        start at the start point or following a newline. The same bug applied to
1786        patterns with negative forward assertions or any backward assertions
1787        preceding ".*" at the start, unless the pattern required a fixed first
1788        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1790    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1791        starting at the last subject character, bytes beyond the end of the subject
1792        string were read.
1794    11. Renamed the variable "class" as "classbits" to make life easier for C++
1795        users. (Previously there was a macro definition, but it apparently wasn't
1796        enough.)
1798    12. Added the new field "tables" to the extra data so that tables can be passed
1799        in at exec time, or the internal tables can be re-selected. This allows
1800        a compiled regex to be saved and re-used at a later time by a different
1801        program that might have everything at different addresses.
1803    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1804        -R library as well as a -L library.
1806    14. The debugging options of pcretest (-d on the command line or D on a
1807        pattern) showed incorrect output for anything following an extended class
1808        that contained multibyte characters and which was followed by a quantifier.
1810    15. Added optional support for general category Unicode character properties
1811        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1812        support. It adds about 90K to the size of the library. The meanings of the
1813        inbuilt class escapes such as \d and \s have NOT been changed.
1815    16. Updated pcredemo.c to include calls to free() to release the memory for the
1816        compiled pattern.
1818    17. The generated file chartables.c was being created in the source directory
1819        instead of in the building directory. This caused the build to fail if the
1820        source directory was different from the building directory, and was
1821        read-only.
1823    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1824        file. No doubt somebody will tell me if they don't make sense... Also added
1825        Dan Mooney's comments about building on OpenVMS.
1827    19. Added support for partial matching via the PCRE_PARTIAL option for
1828        pcre_exec() and the \P data escape in pcretest.
1830    20. Extended pcretest with 3 new pattern features:
1832        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1833              write the compiled pattern to the file whose name is "rest-of-line".
1834              This is a straight binary dump of the data, with the saved pointer to
1835              the character tables forced to be NULL. The study data, if any, is
1836              written too. After writing, pcretest reads a new pattern.
1838        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1839              compiled pattern from the given file. There must not be any
1840              occurrences of "<" in the file name (pretty unlikely); if there are,
1841              pcretest will instead treat the initial "<" as a pattern delimiter.
1842              After reading in the pattern, pcretest goes on to read data lines as
1843              usual.
1845        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1846              and 16-bit fields in a compiled pattern, to simulate a pattern that
1847              was compiled on a host of opposite endianness.
1849    21. The pcre-exec() function can now cope with patterns that were compiled on
1850        hosts of opposite endianness, with this restriction:
1852          As for any compiled expression that is saved and used later, the tables
1853          pointer field cannot be preserved; the extra_data field in the arguments
1854          to pcre_exec() should be used to pass in a tables address if a value
1855          other than the default internal tables were used at compile time.
1857    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1858        now diagnosed as an error. Previously, most of the time, a negative number
1859        would have been treated as zero, but if in addition "ovector" was passed as
1860        NULL, a crash could occur.
1862    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1863        new versions from the libtool 1.5 distribution (the last one is a copy of
1864        a file called libtool.m4). This seems to have fixed the need to patch
1865        "configure" to support Darwin 1.3 (which I used to do). However, I still
1866        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1867        workstation).
1869    24. Changed the PCRE licence to be the more standard "BSD" licence.
1872    Version 4.5 01-Dec-03
1873    ---------------------
1875     1. There has been some re-arrangement of the code for the match() function so
1876        that it can be compiled in a version that does not call itself recursively.
1877        Instead, it keeps those local variables that need separate instances for
1878        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1879        needs to "recurse". Keeping track of where control must go is done by means
1880        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1881        hide most of the details from the main code, and operates only if
1882        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1883        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1884        operating.
1886        To make it easier for callers to provide specially tailored get/free
1887        functions for this usage, two new functions, pcre_stack_malloc, and
1888        pcre_stack_free, are used. They are always called in strict stacking order,
1889        and the size of block requested is always the same.
1891        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1892        PCRE has been compiled to use the stack or the heap for recursion. The
1893        -C option of pcretest uses this to show which version is compiled.
1895        A new data escape \S, is added to pcretest; it causes the amounts of store
1896        obtained and freed by both kinds of malloc/free at match time to be added
1897        to the output.
1899     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1900        what's available on my current Linux desktop machine.
1902     3. When matching a UTF-8 string, the test for a valid string at the start has
1903        been extended. If start_offset is not zero, PCRE now checks that it points
1904        to a byte that is the start of a UTF-8 character. If not, it returns
1905        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1906        this is necessary because there may be backward assertions in the pattern.
1907        When matching the same subject several times, it may save resources to use
1908        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1910     4. The code for checking the validity of UTF-8 strings has been tightened so
1911        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1912        containing "overlong sequences".
1914     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1915        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1916        should have been "&", but it just so happened that all the cases this let
1917        through by mistake were picked up later in the function.
1919     6. I had used a variable called "isblank" - this is a C99 function, causing
1920        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1922     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1923        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1924        so the version is shown; (c) stop "make test" echoing "./RunTest".
1926     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1928     9. The prototype for memmove() for systems that don't have it was using
1929        size_t, but the inclusion of the header that defines size_t was later. I've
1930        moved the #includes for the C headers earlier to avoid this.
1932    10. Added some adjustments to the code to make it easier to compiler on certain
1933        special systems:
1935          (a) Some "const" qualifiers were missing.
1936          (b) Added the macro EXPORT before all exported functions; by default this
1937              is defined to be empty.
1938          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1939              that it reads its output file name as an argument instead of writing
1940              to the standard output and assuming this can be redirected.
1942    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1943        class containing characters with values greater than 255, PCRE compilation
1944        went into a loop.
1946    12. A recursive reference to a subpattern that was within another subpattern
1947        that had a minimum quantifier of zero caused PCRE to crash. For example,
1948        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1949        recursion. If the recursively-called subpattern itself had a zero repeat,
1950        that was OK.
1952    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1953        buffer into which it was copied (for escape processing) was still set at
1954        1024, so long lines caused crashes.
1956    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1957        "internal error: code overflow...". This applied to any character class
1958        that was followed by a possessive quantifier.
1960    15. Modified the Makefile to add libpcre.la as a prerequisite for
1961        libpcreposix.la because I was told this is needed for a parallel build to
1962        work.
1964    16. If a pattern that contained .* following optional items at the start was
1965        studied, the wrong optimizing data was generated, leading to matching
1966        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1967        matching string must start with a or b or c. The correct conclusion for
1968        this pattern is that a match can start with any character.
1971    Version 4.4 13-Aug-03
1972    ---------------------
1974     1. In UTF-8 mode, a character class containing characters with values between
1975        127 and 255 was not handled correctly if the compiled pattern was studied.
1976        In fixing this, I have also improved the studying algorithm for such
1977        classes (slightly).
1979     2. Three internal functions had redundant arguments passed to them. Removal
1980        might give a very teeny performance improvement.
1982     3. Documentation bug: the value of the capture_top field in a callout is *one
1983        more than* the number of the hightest numbered captured substring.
1985     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1986        in incorrectly linking with a previously installed version. They now link
1987        explicitly with libpcre.la.
1989     5. configure.in no longer needs to recognize Cygwin specially.
1991     6. A problem in pcre.in for Windows platforms is fixed.
1993     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1994        pcretest, it used to include the size of the study block as part of its
1995        output. Unfortunately, the structure contains a field that has a different
1996        size on different hardware architectures. This meant that the tests that
1997        showed this size failed. As the block is currently always of a fixed size,
1998        this information isn't actually particularly useful in pcretest output, so
1999        I have just removed it.
2001     8. Three pre-processor statements accidentally did not start in column 1.
2002        Sadly, there are *still* compilers around that complain, even though
2003        standard C has not required this for well over a decade. Sigh.
2005     9. In pcretest, the code for checking callouts passed small integers in the
2006        callout_data field, which is a void * field. However, some picky compilers
2007        complained about the casts involved for this on 64-bit systems. Now
2008        pcretest passes the address of the small integer instead, which should get
2009        rid of the warnings.
2011    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2012        both compile and run time, and gives an error if an invalid UTF-8 sequence
2013        is found. There is a option for disabling this check in cases where the
2014        string is known to be correct and/or the maximum performance is wanted.
2016    11. In response to a bug report, I changed one line in Makefile.in from
2018            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2019        to
2020            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2022        to look similar to other lines, but I have no way of telling whether this
2023        is the right thing to do, as I do not use Windows. No doubt I'll get told
2024        if it's wrong...
2027    Version 4.3 21-May-03
2028    ---------------------
2030    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2031       Makefile.
2033    2. Some refactoring to improve the quality of the code:
2035       (i)   The utf8_table... variables are now declared "const".
2037       (ii)  The code for \cx, which used the "case flipping" table to upper case
2038             lower case letters, now just substracts 32. This is ASCII-specific,
2039             but the whole concept of \cx is ASCII-specific, so it seems
2040             reasonable.
2042       (iii) PCRE was using its character types table to recognize decimal and
2043             hexadecimal digits in the pattern. This is silly, because it handles
2044             only 0-9, a-f, and A-F, but the character types table is locale-
2045             specific, which means strange things might happen. A private
2046             table is now used for this - though it costs 256 bytes, a table is
2047             much faster than multiple explicit tests. Of course, the standard
2048             character types table is still used for matching digits in subject
2049             strings against \d.
2051       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2052             ending in _t are). So I've renamed it as ESC_tee.
2054    3. The first argument for regexec() in the POSIX wrapper should have been
2055       defined as "const".
2057    4. Changed pcretest to use malloc() for its buffers so that they can be
2058       Electric Fenced for debugging.
2060    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2061       to read one or more bytes before the start of the subject string. Often this
2062       had no effect on PCRE's behaviour, but in some circumstances it could
2063       provoke a segmentation fault.
2065    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2066       to try to read one or more bytes before the start of the subject string.
2068    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2069       UTF-8 support could misbehave in various ways if the subject string
2070       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2071       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2072       back over UTF-8 characters.)
2075    Version 4.2 14-Apr-03
2076    ---------------------
2078    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2080    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2081         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2082         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2083         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2084         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2085           and BUILD_EXEEXT
2086         Note: automatic setting of the BUILD variables is not yet working
2087         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2088           compile-time but not at link-time
2089         [LINK]: use for linking executables only
2090         make different versions for Windows and non-Windows
2091         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2092           libraries
2093         [LINK_FOR_BUILD]: new variable
2094         [OBJEXT]: use throughout
2095         [EXEEXT]: use throughout
2096         <winshared>: new target
2097         <wininstall>: new target
2098         <dftables.o>: use native compiler
2099         <dftables>: use native linker
2100         <install>: handle Windows platform correctly
2101         <clean>: ditto
2102         <check>: ditto
2103         copy DLL to top builddir before testing
2105       As part of these changes, -no-undefined was removed again. This was reported
2106       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2107       in any case.
2109    3. Some tidies to get rid of compiler warnings:
2111       . In the match_data structure, match_limit was an unsigned long int, whereas
2112         match_call_count was an int. I've made them both unsigned long ints.
2114       . In pcretest the fact that a const uschar * doesn't automatically cast to
2115         a void * provoked a warning.
2117       . Turning on some more compiler warnings threw up some "shadow" variables
2118         and a few more missing casts.
2120    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2121       option, a class that contained a single character with a value between 128
2122       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2124    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2125       option, a class that contained several characters, but with at least one
2126       whose value was between 128 and 255 caused PCRE to crash.
2129    Version 4.1 12-Mar-03
2130    ---------------------
2132    1. Compiling with gcc -pedantic found a couple of places where casts were
2133    needed, and a string in dftables.c that was longer than standard compilers are
2134    required to support.
2136    2. Compiling with Sun's compiler found a few more places where the code could
2137    be tidied up in order to avoid warnings.
2139    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2140    first of these names is deprecated in the latest Autoconf in favour of the name
2141    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2142    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2143    analogy I have changed it to CFLAGS_FOR_BUILD.
2145    4. Added -no-undefined to the linking command in the Makefile, because this is
2146    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2147    linking step for the pcreposix library.
2149    5. PCRE was failing to diagnose the case of two named groups with the same
2150    name.
2152    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2153    literal character that is needed in the subject for a match, and scans along to
2154    ensure that it is present before embarking on the full matching process. This
2155    saves time in cases of nested unlimited repeats that are never going to match.
2156    Problem: the scan can take a lot of time if the subject is very long (e.g.
2157    megabytes), thus penalizing straightforward matches. It is now done only if the
2158    amount of subject to be scanned is less than 1000 bytes.
2160    7. A lesser problem with the same optimization is that it was recording the
2161    first character of an anchored pattern as "needed", thus provoking a search
2162    right along the subject, even when the first match of the pattern was going to
2163    fail. The "needed" character is now not set for anchored patterns, unless it
2164    follows something in the pattern that is of non-fixed length. Thus, it still
2165    fulfils its original purpose of finding quick non-matches in cases of nested
2166    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2169    Version 4.0 17-Feb-03
2170    ---------------------
2172    1. If a comment in an extended regex that started immediately after a meta-item
2173    extended to the end of string, PCRE compiled incorrect data. This could lead to
2174    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2176    2. Moved to autoconf 2.53 and libtool 1.4.2.
2178    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2179    the special perltest8 script is no longer needed - all the tests can be run
2180    from a single perltest script.
2182    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2183    by \s. It has now been removed in PCRE. This means it isn't recognized as
2184    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2185    class [:space:] *does* include VT, thereby creating a mess.
2187    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2188    space and tab.
2190    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2191    its new features into the main test script, reducing the number of scripts.
2193    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2194    were backward compatible, and made the (?i) apply to the whole pattern, as if
2195    /i were given. Now it behaves more logically, and applies the option setting
2196    only to what follows. PCRE has been changed to follow suit. However, if it
2197    finds options settings right at the start of the pattern, it extracts them into
2198    the global options, as before. Thus, they show up in the info data.
2200    8. Added support for the \Q...\E escape sequence. Characters in between are
2201    treated as literals. This is slightly different from Perl in that $ and @ are
2202    also handled as literals inside the quotes. In Perl, they will cause variable
2203    interpolation. Note the following examples:
2205        Pattern            PCRE matches      Perl matches
2207        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2208        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2209        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2211    For compatibility with Perl, \Q...\E sequences are recognized inside character
2212    classes as well as outside them.
2214    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2215    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2216    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2217    signed/unsigned warnings.
2219    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2220    option for pcretest, so I've replaced it by a simple function that does just
2221    that job.
2223    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2224    "pcregrep -".
2226    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2227    Java package. This provides some syntactic sugar for simple cases of what my
2228    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2229    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2230    item, you can use this simplified notation. Note that only makes sense with
2231    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2232    greediness, whatever the setting of the PCRE_UNGREEDY option.
2234    13. A change of greediness default within a pattern was not taking effect at
2235    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2236    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2237    was abstracted outside.
2239    14. PCRE now supports the \G assertion. It is true when the current matching
2240    position is at the start point of the match. This differs from \A when the
2241    starting offset is non-zero. Used with the /g option of pcretest (or similar
2242    code), it works in the same way as it does for Perl's /g option. If all
2243    alternatives of a regex begin with \G, the expression is anchored to the start
2244    match position, and the "anchored" flag is set in the compiled expression.
2246    15. Some bugs concerning the handling of certain option changes within patterns
2247    have been fixed. These applied to options other than (?ims). For example,
2248    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2249    been the other way round. Some of this was related to change 7 above.
2251    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2252    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2253    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2254    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2256    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2257    mode. Unlike ".", it always matches newline, whatever the setting of
2258    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2259    assertions. Perl allows it, but it doesn't (in general) work because it can't
2260    calculate the length of the lookbehind. At least, that's the case for Perl
2261    5.8.0 - I've been told they are going to document that it doesn't work in
2262    future.
2264    18. Added an error diagnosis for escapes that PCRE does not support: these are
2265    \L, \l, \N, \P, \p, \U, \u, and \X.
2267    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2268    reading past the end of the pattern in cases such as /[abcd/.
2270    20. PCRE was getting more memory than necessary for patterns with classes that
2271    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2273    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2274    compiling PCRE for use with Virtual Pascal.
2276    22. Small fix to the Makefile to make it work properly if the build is done
2277    outside the source tree.
2279    23. Added a new extension: a condition to go with recursion. If a conditional
2280    subpattern starts with (?(R) the "true" branch is used if recursion has
2281    happened, whereas the "false" branch is used only at the top level.
2283    24. When there was a very long string of literal characters (over 255 bytes
2284    without UTF support, over 250 bytes with UTF support), the computation of how
2285    much memory was required could be incorrect, leading to segfaults or other
2286    strange effects.
2288    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2289    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2290    there was a subsequent back reference to those brackets. This meant that, for
2291    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2292    possible to check for precisely this case. All we can do is abandon the
2293    optimization if .* occurs inside capturing brackets when there are any back
2294    references whatsoever. (See below for a better fix that came later.)
2296    26. The handling of the optimization for finding the first character of a
2297    non-anchored pattern, and for finding a character that is required later in the
2298    match were failing in some cases. This didn't break the matching; it just
2299    failed to optimize when it could. The way this is done has been re-implemented.
2301    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2303    28. Added a new feature that provides some of the functionality that Perl
2304    provides with (?{...}). The facility is termed a "callout". The way it is done
2305    in PCRE is for the caller to provide an optional function, by setting
2306    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2307    global variable. By default it is unset, which disables all calling out. To get
2308    the function called, the regex must include (?C) at appropriate points. This
2309    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2310    This provides a means of identifying different callout points. When PCRE
2311    reaches such a point in the regex, if pcre_callout has been set, the external
2312    function is called. It is provided with data in a structure called
2313    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2314    matching continues; if it returns a non-zero value, the match at the current
2315    point fails. However, backtracking will occur if possible. [This was changed
2316    later and other features added - see item 49 below.]
2318    29. pcretest is upgraded to test the callout functionality. It provides a
2319    callout function that displays information. By default, it shows the start of
2320    the match and the current position in the text. There are some new data escapes
2321    to vary what happens:
2323        \C+         in addition, show current contents of captured substrings
2324        \C-         do not supply a callout function
2325        \C!n        return 1 when callout number n is reached
2326        \C!n!m      return 1 when callout number n is reached for the mth time
2328    30. If pcregrep was called with the -l option and just a single file name, it
2329    output "<stdin>" if a match was found, instead of the file name.
2331    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2332    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2333    pcre_exec(). This saves a malloc/free per call. The default value of
2334    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2335    when configuring.
2337    32. The default maximum size of a compiled pattern is 64K. There have been a
2338    few cases of people hitting this limit. The code now uses macros to handle the
2339    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2340    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2341    configuring. Tests 2 and 5 work only with 2-byte links because they output
2342    debugging information about compiled patterns.
2344    33. Internal code re-arrangements:
2346    (a) Moved the debugging function for printing out a compiled regex into
2347        its own source file (printint.c) and used #include to pull it into
2348        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2349        separate copies.
2351    (b) Defined the list of op-code names for debugging as a macro in
2352        internal.h so that it is next to the definition of the opcodes.
2354    (c) Defined a table of op-code lengths for simpler skipping along compiled
2355        code. This is again a macro in internal.h so that it is next to the
2356        definition of the opcodes.
2358    34. Added support for recursive calls to individual subpatterns, along the
2359    lines of Robin Houston's patch (but implemented somewhat differently).
2361    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2362    allow it to read and process whole directories in Win32. This code was
2363    contributed by Lionel Fourquaux; it has not been tested by me.
2365    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2366    used to name a group. Names consist of alphanumerics and underscores, and must
2367    be unique. Back references use the syntax (?P=name) and recursive calls use
2368    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2369    numbers. The function pcre_fullinfo() can be used after compilation to extract
2370    a name/number map. There are three relevant calls:
2372      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2373      PCRE_INFO_NAMECOUNT            yields the number of entries
2374      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2376    The map is a vector of fixed-size entries. The size of each entry depends on
2377    the length of the longest name used. The first two bytes of each entry are the
2378    group number, most significant byte first. There follows the corresponding
2379    name, zero terminated. The names are in alphabetical order.
2381    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2382    case instead of 255. Making it the same both with and without UTF-8 support
2383    means that the same test output works with both.
2385    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2386    calling malloc() with a zero argument.
2388    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2389    optimization. I've improved things by keeping a bitmap of backreferences with
2390    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2391    fact referenced, the optimization can be applied. It is unlikely that a
2392    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2393    the match to follow \n) will appear inside brackets with a number greater than
2394    31, but if it does, any back reference > 31 suppresses the optimization.
2396    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2397    of disabling numbered capturing parentheses. Any opening parenthesis that is
2398    not followed by ? behaves as if it were followed by ?: but named parentheses
2399    can still be used for capturing (and they will acquire numbers in the usual
2400    way).
2402    41. Redesigned the return codes from the match() function into yes/no/error so
2403    that errors can be passed back from deep inside the nested calls. A malloc
2404    failure while inside a recursive subpattern call now causes the
2405    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2407    42. It is now possible to set a limit on the number of times the match()
2408    function is called in a call to pcre_exec(). This facility makes it possible to
2409    limit the amount of recursion and backtracking, though not in a directly
2410    obvious way, because the match() function is used in a number of different
2411    circumstances. The count starts from zero for each position in the subject
2412    string (for non-anchored patterns). The default limit is, for compatibility, a
2413    large number, namely 10 000 000. You can change this in two ways:
2415    (a) When configuring PCRE before making, you can use --with-match-limit=n
2416        to set a default value for the compiled library.
2418    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2419        a different value is set. See 45 below.
2421    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2423    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2424    of things that can be changed at compile time. The first argument specifies
2425    what is wanted and the second points to where the information is to be placed.
2426    The current list of available information is:
2428      PCRE_CONFIG_UTF8
2430    The output is an integer that is set to one if UTF-8 support is available;
2431    otherwise it is set to zero.
2435    The output is an integer that it set to the value of the code that is used for
2436    newline. It is either LF (10) or CR (13).
2440    The output is an integer that contains the number of bytes used for internal
2441    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2445    The output is an integer that contains the threshold above which the POSIX
2446    interface uses malloc() for output vectors. See item 31 above.
2450    The output is an unsigned integer that contains the default limit of the number
2451    of match() calls in a pcre_exec() execution. See 42 above.
2453    44. pcretest has been upgraded by the addition of the -C option. This causes it
2454    to extract all the available output from the new pcre_config() function, and to
2455    output it. The program then exits immediately.
2457    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2458    order to support additional features. One way would have been to define
2459    pcre_exec2() (for example) with extra arguments, but this would not have been
2460    extensible, and would also have required all calls to the original function to
2461    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2462    is used for passing in "extra" data from pcre_study().
2464    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2465    contains the following fields:
2467      flags         a bitmap indicating which of the following fields are set
2468      study_data    opaque data from pcre_study()
2469      match_limit   a way of specifying a limit on match() calls for a specific
2470                      call to pcre_exec()
2471      callout_data  data for callouts (see 49 below)
2473    The flag bits are also defined in pcre.h, and are
2479    The pcre_study() function now returns one of these new pcre_extra blocks, with
2480    the actual study data pointed to by the study_data field, and the
2481    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2482    before. That is, this change is entirely upwards-compatible and requires no
2483    change to existing code.
2485    If you want to pass in additional data to pcre_exec(), you can either place it
2486    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2487    block.
2489    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2490    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2491    times with different match limits, until it finds the minimum value needed for
2492    pcre_exec() to complete. The value is then output. This can be instructive; for
2493    most simple matches the number is quite small, but for pathological cases it
2494    gets very large very quickly.
2496    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2497    returns the size of the data block pointed to by the study_data field in a
2498    pcre_extra block, that is, the value that was passed as the argument to
2499    pcre_malloc() when PCRE was getting memory in which to place the information
2500    created by pcre_study(). The fourth argument should point to a size_t variable.
2501    pcretest has been extended so that this information is shown after a successful
2502    pcre_study() call when information about the compiled regex is being displayed.
2504    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2505    because what follows is always an absolute path. (Later: it turns out that this
2506    is more than cosmetic for MinGW, because it doesn't like empty path
2507    components.)
2509    49. Some changes have been made to the callout feature (see 28 above):
2511    (i)  A callout function now has three choices for what it returns:
2513           0  =>  success, carry on matching
2514         > 0  =>  failure at this point, but backtrack if possible
2515         < 0  =>  serious error, return this value from pcre_exec()
2517         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2518         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2519         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2520         use by callout functions. It will never be used by PCRE itself.
2522    (ii) The pcre_extra structure (see 45 above) has a void * field called
2523         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2524         pcre_callout_block structure has a field of the same name. The contents of
2525         the field passed in the pcre_extra structure are passed to the callout
2526         function in the corresponding field in the callout block. This makes it
2527         easier to use the same callout-containing regex from multiple threads. For
2528         testing, the pcretest program has a new data escape
2530           \C*n        pass the number n (may be negative) as callout_data
2532         If the callout function in pcretest receives a non-zero value as
2533         callout_data, it returns that value.
2535    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2536    there were some redundant $(CFLAGS) in commands that are now specified as
2537    $(LINK), which already includes $(CFLAGS).
2539    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2540    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2541    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2542    one-byte characters throughout. Note that case-insensitive matching applies
2543    only to characters whose values are less than 256. PCRE doesn't support the
2544    notion of cases for higher-valued characters.
2546    (i)   A character class whose characters are all within 0-255 is handled as
2547          a bit map, and the map is inverted for negative classes. Previously, a
2548          character > 255 always failed to match such a class; however it should
2549          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2551    (ii)  A negated character class with a single character < 255 is coded as
2552          "not this character" (OP_NOT). This wasn't working properly when the test
2553          character was multibyte, either singly or repeated.
2555    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2556          mode, for example: \x{100}{2,3}.
2558    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2559          singly or repeated) now correctly test multibyte characters. However,
2560          PCRE doesn't recognize any characters with values greater than 255 as
2561          digits, spaces, or word characters. Such characters always match \D, \S,
2562          and \W, and never match \d, \s, or \w.
2564    (v)   Classes may now contain characters and character ranges with values
2565          greater than 255. For example: [ab\x{100}-\x{400}].
2567    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2568          PCRE in UTF-8 mode.
2570    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2571    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2572    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2573    value.)
2575    53. The single man page has become too large. I have therefore split it up into
2576    a number of separate man pages. These also give rise to individual HTML pages;
2577    these are now put in a separate directory, and there is an index.html page that
2578    lists them all. Some hyperlinking between the pages has been installed.
2580    54. Added convenience functions for handling named capturing parentheses.
2582    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2583    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2584    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2585    are faulted.
2587    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2588    calling configure. These values are used when compiling the dftables.c program
2589    which is run to generate the source of the default character tables. They
2590    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2591    you will need to set these values.
2593    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2596    Version 3.9 02-Jan-02
2597    ---------------------
2599    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2601    2. If --disable-static was given, the building process failed when trying to
2602    build pcretest and pcregrep. (For some reason it was using libtool to compile
2603    them, which is not right, as they aren't part of the library.)
2606    Version 3.8 18-Dec-01
2607    ---------------------
2609    1. The experimental UTF-8 code was completely screwed up. It was packing the
2610    bytes in the wrong order. How dumb can you get?
2613    Version 3.7 29-Oct-01
2614    ---------------------
2616    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2617    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2618    this didn't happen under Solaris 8, where I normally test things.
2620    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2621    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2622    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2623    this fix an hour or so after the initial 3.7 release.)
2626    Version 3.6 23-Oct-01
2627    ---------------------
2629    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2630    offsets passed as NULL with zero offset count.
2632    2. The config.guess and config.sub files had not been updated when I moved to
2633    the latest autoconf.
2636    Version 3.5 15-Aug-01
2637    ---------------------
2639    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2640    had been forgotten.
2642    2. By using declared but undefined structures, we can avoid using "void"
2643    definitions in pcre.h while keeping the internal definitions of the structures
2644    private.
2646    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2647    user point of view, this means that both static and shared libraries are built
2648    by default, but this can be individually controlled. More of the work of
2649    handling this static/shared cases is now inside libtool instead of PCRE's make
2650    file.
2652    4. The pcretest utility is now installed along with pcregrep because it is
2653    useful for users (to test regexs) and by doing this, it automatically gets
2654    relinked by libtool. The documentation has been turned into a man page, so
2655    there are now .1, .txt, and .html versions in /doc.
2657    5. Upgrades to pcregrep:
2658       (i)   Added long-form option names like gnu grep.
2659       (ii)  Added --help to list all options with an explanatory phrase.
2660       (iii) Added -r, --recursive to recurse into sub-directories.
2661       (iv)  Added -f, --file to read patterns from a file.
2663    6. pcre_exec() was referring to its "code" argument before testing that
2664    argument for NULL (and giving an error if it was NULL).
2666    7. Upgraded Makefile.in to allow for compiling in a different directory from
2667    the source directory.
2669    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2670    options bits, the pointer it was passed was to an int instead of to an unsigned
2671    long int. This mattered only on 64-bit systems.
2673    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2674    generated) instead of pcre.in, which it its source. Also made the same change
2675    in several of the .c files.
2677    10. A new release of gcc defines printf() as a macro, which broke pcretest
2678    because it had an ifdef in the middle of a string argument for printf(). Fixed
2679    by using separate calls to printf().
2681    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2682    script, to force use of CR or LF instead of \n in the source. On non-Unix
2683    systems, the value can be set in config.h.
2685    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2686    absolute limit. Changed the text of the error message to make this clear, and
2687    likewise updated the man page.
2689    13. The limit of 99 on the number of capturing subpatterns has been removed.
2690    The new limit is 65535, which I hope will not be a "real" limit.
2693    Version 3.4 22-Aug-00
2694    ---------------------
2696    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2698    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2701    Version 3.3 01-Aug-00
2702    ---------------------
2704    1. If an octal character was given, but the value was greater than \377, it
2705    was not getting masked to the least significant bits, as documented. This could
2706    lead to crashes in some systems.
2708    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2709    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2711    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2712    These just pass their arguments on to (pcre_free)(), but they are provided
2713    because some uses of PCRE bind it to non-C systems that can call its functions,
2714    but cannot call free() or pcre_free() directly.
2716    4. Add "make test" as a synonym for "make check". Corrected some comments in
2717    the Makefile.
2719    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2720    Makefile.
2722    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2723    command called pgrep for grepping around the active processes.
2725    7. Added the beginnings of support for UTF-8 character strings.
2727    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2728    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2729    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2730    out for the ar command.)
2733    Version 3.2 12-May-00
2734    ---------------------
2736    This is purely a bug fixing release.
2738    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2739    of ZA. This was just one example of several cases that could provoke this bug,
2740    which was introduced by change 9 of version 2.00. The code for breaking
2741    infinite loops after an iteration that matches an empty string was't working
2742    correctly.
2744    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2745    when matched against abbab (for example). After matching an empty string, it
2746    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2747    caused it to match further down the string than it should.
2749    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2750    was there because it doesn't seem to be needed, and it causes trouble on some
2751    systems, as it is not a Standard C header. It has been removed.
2753    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2754    were reported on the Macintosh. The changes were from
2756      while ((c = *(++ptr)) != 0 && c != '\n');
2757    to
2758      while ((c = *(++ptr)) != 0 && c != '\n') ;
2760    Totally extraordinary, but if that's what it takes...
2762    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2763    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2764    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2765    assumes the way PCRE uses memmove() (always moving upwards).
2767    6. PCRE is being used in one environment where strchr() is not available. There
2768    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2769    faster code anyway.
2772    Version 3.1 09-Feb-00
2773    ---------------------
2775    The only change in this release is the fixing of some bugs in Makefile.in for
2776    the "install" target:
2778    (1) It was failing to install pcreposix.h.
2780    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2783    Version 3.0 01-Feb-00
2784    ---------------------
2786    1. Add support for the /+ modifier to perltest (to output $` like it does in
2787    pcretest).
2789    2. Add support for the /g modifier to perltest.
2791    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2792    matches null strings.
2794    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2795    pattern. Perl treats empty patterns specially - it reuses the most recent
2796    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2797    effect.
2799    5. The POSIX interface was broken in that it was just handing over the POSIX
2800    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2801    required a bigger vector, with some working space on the end. This means that
2802    the POSIX wrapper now has to get and free some memory, and copy the results.
2804    6. Added some simple autoconf support, placing the test data and the
2805    documentation in separate directories, re-organizing some of the
2806    information files, and making it build pcre-config (a GNU standard). Also added
2807    libtool support for building PCRE as a shared library, which is now the
2808    default.
2810    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2811    09 are not valid octal constants. Single digits will be used for minor values
2812    less than 10.
2814    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2815    existing programs that set these in the POSIX interface can use PCRE without
2816    modification.
2818    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2819    return all that pcre_info() returns, plus additional data. The pcre_info()
2820    function is retained for compatibility, but is considered to be obsolete.
2822    10. Added experimental recursion feature (?R) to handle one common case that
2823    Perl 5.6 will be able to do with (?p{...}).
2825    11. Added support for POSIX character classes like [:alpha:], which Perl is
2826    adopting.
2829    Version 2.08 31-Aug-99
2830    ----------------------
2832    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2833    trying to match at the startoffset position, but instead was moving forward to
2834    the next newline as if a previous match had failed.
2836    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2837    and could get into a loop if a null string was matched other than at the start
2838    of the subject.
2840    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2841    be distinguished at compile time, and for completeness also added PCRE_DATE.
2843    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2844    in GnuWin32 environments.
2847    Version 2.07 29-Jul-99
2848    ----------------------
2850    1. The documentation is now supplied in plain text form and HTML as well as in
2851    the form of man page sources.
2853    2. C++ compilers don't like assigning (void *) values to other pointer types.
2854    In particular this affects malloc(). Although there is no problem in Standard
2855    C, I've put in casts to keep C++ compilers happy.
2857    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2858    should be (const char *).
2860    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2861    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2862    However, I haven't made this a standard facility. The documentation doesn't
2863    mention it, and the Makefile doesn't support it.
2865    5. The Makefile now contains an "install" target, with editable destinations at
2866    the top of the file. The pcretest program is not installed.
2868    6. pgrep -V now gives the PCRE version number and date.
2870    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2871    causing the entire string to be ignored, instead of just the last character.
2873    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2874    non-matching string, it can take a very, very long time, even for strings of
2875    quite modest length, because of the nested recursion. PCRE now does better in
2876    some of these cases. It does this by remembering the last required literal
2877    character in the pattern, and pre-searching the subject to ensure it is present
2878    before running the real match. In other words, it applies a heuristic to detect
2879    some types of certain failure quickly, and in the above example, if presented
2880    with a string that has no trailing " it gives "no match" very quickly.
2882    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2883    other alternatives are tried instead.
2886    Version 2.06 09-Jun-99
2887    ----------------------
2889    1. Change pcretest's output for amount of store used to show just the code
2890    space, because the remainder (the data block) varies in size between 32-bit and
2891    64-bit systems.
2893    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2894    start matching at. This allows lookbehinds to work when searching for multiple
2895    occurrences in a string.
2897    3. Added additional options to pcretest for testing multiple occurrences:
2899       /+   outputs the rest of the string that follows a match
2900       /g   loops for multiple occurrences, using the new startoffset argument
2901       /G   loops for multiple occurrences by passing an incremented pointer
2903    4. PCRE wasn't doing the "first character" optimization for patterns starting
2904    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2905    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2906    the letter 'x'. On long subject strings, this gives a significant speed-up.
2909    Version 2.05 21-Apr-99
2910    ----------------------
2912    1. Changed the type of magic_number from int to long int so that it works
2913    properly on 16-bit systems.
2915    2. Fixed a bug which caused patterns starting with .* not to work correctly
2916    when the subject string contained newline characters. PCRE was assuming
2917    anchoring for such patterns in all cases, which is not correct because .* will
2918    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2919    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2920    must be retried after every newline in the subject.
2923    Version 2.04 18-Feb-99
2924    ----------------------
2926    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2927    computation of the store needed to hold the pattern was incorrect (too large).
2928    If such patterns were nested a few deep, this could multiply and become a real
2929    problem.
2931    2. Added /M option to pcretest to show the memory requirement of a specific
2932    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2934    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2935    compiled in such a way that the backtracking after subsequent failure was
2936    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2937    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2940    Version 2.03 02-Feb-99
2941    ----------------------
2943    1. Fixed typo and small mistake in man page.
2945    2. Added 4th condition (GPL supersedes if conflict) and created separate
2946    LICENCE file containing the conditions.
2948    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2949    Perl, that is the internal \ allows the delimiter to be included in the
2950    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2951    the final delimiter, add \ to the end of the pattern (to test the error).
2953    4. Added the convenience functions for extracting substrings after a successful
2954    match. Updated pcretest to make it able to test these functions.
2957    Version 2.02 14-Jan-99
2958    ----------------------
2960    1. Initialized the working variables associated with each extraction so that
2961    their saving and restoring doesn't refer to uninitialized store.
2963    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2964    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2965    fix the problem.
2967    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2968    calls, and wasn't printing the correct value for compiling calls. Increased the
2969    default value of LOOPREPEAT, and the number of significant figures in the
2970    times.
2972    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2974    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2975    a building problem on Windows NT with a FAT file system.
2978    Version 2.01 21-Oct-98
2979    ----------------------
2981    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2982    to character tables built by pcre_maketables() in the current locale. If NULL
2983    is passed, the default tables are used.
2986    Version 2.00 24-Sep-98
2987    ----------------------
2989    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2990    it any more.
2992    2. Allow quantification of (?>) groups, and make it work correctly.
2994    3. The first character computation wasn't working for (?>) groups.
2996    4. Correct the implementation of \Z (it is permitted to match on the \n at the
2997    end of the subject) and add 5.005's \z, which really does match only at the
2998    very end of the subject.
3000    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3002    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3003    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3004    localized options. All options to pcre_study() were also removed.
3006    7. Add other new features from 5.005:
3008       $(?<=           positive lookbehind
3009       $(?<!           negative lookbehind
3010       (?imsx-imsx)    added the unsetting capability
3011                       such a setting is global if at outer level; local otherwise
3012       (?imsx-imsx:)   non-capturing groups with option setting
3013       (?(cond)re|re)  conditional pattern matching
3015       A backreference to itself in a repeated group matches the previous
3016       captured string.
3018    8. General tidying up of studying (both automatic and via "study")
3019    consequential on the addition of new assertions.
3021    9. As in 5.005, unlimited repeated groups that could match an empty substring
3022    are no longer faulted at compile time. Instead, the loop is forcibly broken at
3023    runtime if any iteration does actually match an empty substring.
3025    10. Include the RunTest script in the distribution.
3027    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3028    discrepancies, some of which were old and were also with respect to 5.004. They
3029    have now been fixed.
3032    Version 1.09 28-Apr-98
3033    ----------------------
3035    1. A negated single character class followed by a quantifier with a minimum
3036    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
3037    program crashes, or just wrong answers. This did not apply to negated classes
3038    containing more than one character, or to minima other than one.
3041    Version 1.08 27-Mar-98
3042    ----------------------
3044    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3046    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3047    latter must appear before anything that relies on it in the pattern.
3050    Version 1.07 16-Feb-98
3051    ----------------------
3053    1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3054    repeat of a potentially empty string).
3057    Version 1.06 23-Jan-98
3058    ----------------------
3060    1. Added Markus Oberhumer's little patches for C++.
3062    2. Literal strings longer than 255 characters were broken.
3065    Version 1.05 23-Dec-97
3066    ----------------------
3068    1. Negated character classes containing more than one character were failing if
3069    PCRE_CASELESS was set at run time.
3072    Version 1.04 19-Dec-97
3073    ----------------------
3075    1. Corrected the man page, where some "const" qualifiers had been omitted.
3077    2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3078    input syntax.
3080    3. Fixed memory leak which occurred when a regex with back references was
3081    matched with an offsets vector that wasn't big enough. The temporary memory
3082    that is used in this case wasn't being freed if the match failed.
3084    4. Tidied pcretest to ensure it frees memory that it gets.
3086    5. Temporary memory was being obtained in the case where the passed offsets
3087    vector was exactly big enough.
3089    6. Corrected definition of offsetof() from change 5 below.
3091    7. I had screwed up change 6 below and broken the rules for the use of
3092    setjmp(). Now fixed.
3095    Version 1.03 18-Dec-97
3096    ----------------------
3098    1. A erroneous regex with a missing opening parenthesis was correctly
3099    diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3100    on some systems.
3102    2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3103    it was reported that one broken compiler failed on the former because "code" is
3104    also an independent variable.
3106    3. The erroneous regex a[]b caused an array overrun reference.
3108    4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3109    fail on data ending with that character. (It was going on too far, and checking
3110    the next character, typically a binary zero.) This was specific to the
3111    optimized code for single-character negative classes.
3113    5. Added a contributed patch from the TIN world which does the following:
3115      + Add an undef for memmove, in case the the system defines a macro for it.
3117      + Add a definition of offsetof(), in case there isn't one. (I don't know
3118        the reason behind this - offsetof() is part of the ANSI standard - but
3119        it does no harm).
3121      + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3122        most of the places where whitespace preceded '#'. I have given up and
3123        allowed the remaining 2 cases to be at the margin.
3125      + Rename some variables in pcre to eliminate shadowing. This seems very
3126        pedantic, but does no harm, of course.
3128    6. Moved the call to setjmp() into its own function, to get rid of warnings
3129    from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3131    7. Constructs such as \d{8,} were compiling into the equivalent of
3132    \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3133    outcome, but in this particular case used more store than had been allocated,
3134    which caused the bug to be discovered because it threw up an internal error.
3136    8. The debugging code in both pcre and pcretest for outputting the compiled
3137    form of a regex was going wrong in the case of back references followed by
3138    curly-bracketed repeats.
3141    Version 1.02 12-Dec-97
3142    ----------------------
3144    1. Typos in pcre.3 and comments in the source fixed.
3146    2. Applied a contributed patch to get rid of places where it used to remove
3147    'const' from variables, and fixed some signed/unsigned and uninitialized
3148    variable warnings.
3150    3. Added the "runtest" target to Makefile.
3152    4. Set default compiler flag to -O2 rather than just -O.
3155    Version 1.01 19-Nov-97
3156    ----------------------
3158    1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3159    like /([ab]*)*/, that is, for classes with more than one character in them.
3161    2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3162    as /((?>a*))*/ (a PCRE_EXTRA facility).
3165    Version 1.00 18-Nov-97
3166    ----------------------
3168    1. Added compile-time macros to support systems such as SunOS4 which don't have
3169    memmove() or strerror() but have other things that can be used instead.
3171    2. Arranged that "make clean" removes the executables.
3174  Version 0.99 27-Oct-97  Version 0.99 27-Oct-97
3175  ----------------------  ----------------------

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