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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.
26    Version 7.7 07-May-08
27    ---------------------
29    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
30        a string to a long long, pretend we don't even have a long long." This is
31        done by checking for the strtoq, strtoll, and _strtoi64 functions.
33    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
34        pre-7.6 versions, which defined a global no_arg variable instead of putting
35        it in the RE class. (See also #8 below.)
37    3.  Remove a line of dead code, identified by coverity and reported by Nuno
38        Lopes.
40    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
42        (1) The include/exclude patterns were being applied to the whole pathnames
43            of files, instead of just to the final components.
45        (2) If there was more than one level of directory, the subdirectories were
46            skipped unless they satisfied the include/exclude conditions. This is
47            inconsistent with GNU grep (and could even be seen as contrary to the
48            pcregrep specification - which I improved to make it absolutely clear).
49            The action now is always to scan all levels of directory, and just
50            apply the include/exclude patterns to regular files.
52    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
53        --exclude_dir in the tests to avoid scanning .svn directories.
55    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
56        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
57        doesn't support NULs in patterns.
59    7.  Added some missing "const"s to declarations of static tables in
60        pcre_compile.c and pcre_dfa_exec.c.
62    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
63        caused by fix #2  above. (Subsequently also a second patch to fix the
64        first patch. And a third patch - this was a messy problem.)
66    9.  Applied Craig's patch to remove the use of push_back().
68    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
69        matching function regexec().
71    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
72        which, however, unlike Perl's \g{...}, are subroutine calls, not back
73        references. PCRE supports relative numbers with this syntax (I don't think
74        Oniguruma does).
76    12. Previously, a group with a zero repeat such as (...){0} was completely
77        omitted from the compiled regex. However, this means that if the group
78        was called as a subroutine from elsewhere in the pattern, things went wrong
79        (an internal error was given). Such groups are now left in the compiled
80        pattern, with a new opcode that causes them to be skipped at execution
81        time.
83    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
84        to the way PCRE behaves:
86        (a) A lone ] character is dis-allowed (Perl treats it as data).
88        (b) A back reference to an unmatched subpattern matches an empty string
89            (Perl fails the current match path).
91        (c) A data ] in a character class must be notated as \] because if the
92            first data character in a class is ], it defines an empty class. (In
93            Perl it is not possible to have an empty class.) The empty class []
94            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
95            The negative empty class [^] matches any one character, independently
96            of the DOTALL setting.
98    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
99        non-existent subpattern following a character class starting with ']' and
100        containing () gave an internal compiling error instead of "reference to
101        non-existent subpattern". Fortunately, when the pattern did exist, the
102        compiled code was correct. (When scanning forwards to check for the
103        existencd of the subpattern, it was treating the data ']' as terminating
104        the class, so got the count wrong. When actually compiling, the reference
105        was subsequently set up correctly.)
107    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
108        it was being rejected as not supported by pcre_dfa_exec(), even though
109        other assertions are supported. I have made pcre_dfa_exec() support
110        (*FAIL).
112    16. The implementation of 13c above involved the invention of a new opcode,
113        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
114        cannot be changed at match time, I realized I could make a small
115        improvement to matching performance by compiling OP_ALLANY instead of
116        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
117        on the OP_ANY path.
119    17. Compiling pcretest on Windows with readline support failed without the
120        following two fixes: (1) Make the unistd.h include conditional on
121        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
123    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
124        ncurses library to be included for pcretest when ReadLine support is
125        requested, but also to allow for it to be overridden. This patch came from
126        Daniel Bergström.
128    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
129        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
130        any errors with the current Unicode tables. Thanks to Peter Kankowski for
131        spotting this.
134    Version 7.6 28-Jan-08
135    ---------------------
137    1.  A character class containing a very large number of characters with
138        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
139        overflow.
141    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
142        HAVE_LONG_LONG is not defined.
144    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
145        bring them up to date and include new features. This patch includes:
147        - Fixed PH's badly added libz and libbz2 support.
148        - Fixed a problem with static linking.
149        - Added pcredemo. [But later removed - see 7 below.]
150        - Fixed dftables problem and added an option.
151        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
152            HAVE_LONG_LONG.
153        - Added readline support for pcretest.
154        - Added an listing of the option settings after cmake has run.
156    4.  A user submitted a patch to Makefile that makes it easy to create
157        "pcre.dll" under mingw when using Configure/Make. I added stuff to
158        Makefile.am that cause it to include this special target, without
159        affecting anything else. Note that the same mingw target plus all
160        the other distribution libraries and programs are now supported
161        when configuring with CMake (see 6 below) instead of with
162        Configure/Make.
164    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
165        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
166        exported in the Windows port". It has not yet been confirmed that the patch
167        solves the problem, but it does no harm.
169    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
170        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
171        with CMake, and also correct the comment about stack recursion.
173    7.  Remove the automatic building of pcredemo from the ./configure system and
174        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
175        of a program that users should build themselves after PCRE is installed, so
176        building it automatically is not really right. What is more, it gave
177        trouble in some build environments.
179    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
182    Version 7.5 10-Jan-08
183    ---------------------
185    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
186        values in parens when parsing an RE using the C++ wrapper."
188    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
189        Characters greater than 255 were excluded from the class instead of being
190        included.
192    3.  The same bug as (2) above applied to negated POSIX classes such as
193        [:^space:].
195    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
196        defined or documented. It seems to have been a typo for PCRE_STATIC, so
197        I have changed it.
199    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
200        first named subpattern) and a construct such as (?&a) would reference the
201        first named subpattern whose name started with "a" (in other words, the
202        length check was missing). Both these problems are fixed. "Subpattern name
203        expected" is now given for (?&) (a zero-length name), and this patch also
204        makes it give the same error for \k'' (previously it complained that that
205        was a reference to a non-existent subpattern).
207    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
208        this is right because (?- can be followed by option settings as well as by
209        digits. I have, however, made the messages clearer.
211    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
212        than the number used in the conditional) now cause a compile-time error.
213        This is actually not compatible with Perl, which accepts such patterns, but
214        treats the conditional as always being FALSE (as PCRE used to), but it
215        seems to me that giving a diagnostic is better.
217    8.  Change "alphameric" to the more common word "alphanumeric" in comments
218        and messages.
220    9.  Fix two occurrences of "backslash" in comments that should have been
221        "backspace".
223    10. Remove two redundant lines of code that can never be obeyed (their function
224        was moved elsewhere).
226    11. The program that makes PCRE's Unicode character property table had a bug
227        which caused it to generate incorrect table entries for sequences of
228        characters that have the same character type, but are in different scripts.
229        It amalgamated them into a single range, with the script of the first of
230        them. In other words, some characters were in the wrong script. There were
231        thirteen such cases, affecting characters in the following ranges:
233          U+002b0 - U+002c1
234          U+0060c - U+0060d
235          U+0061e - U+00612
236          U+0064b - U+0065e
237          U+0074d - U+0076d
238          U+01800 - U+01805
239          U+01d00 - U+01d77
240          U+01d9b - U+01dbf
241          U+0200b - U+0200f
242          U+030fc - U+030fe
243          U+03260 - U+0327f
244          U+0fb46 - U+0fbb1
245          U+10450 - U+1049d
247    12. The -o option (show only the matching part of a line) for pcregrep was not
248        compatible with GNU grep in that, if there was more than one match in a
249        line, it showed only the first of them. It now behaves in the same way as
250        GNU grep.
252    13. If the -o and -v options were combined for pcregrep, it printed a blank
253        line for every non-matching line. GNU grep prints nothing, and pcregrep now
254        does the same. The return code can be used to tell if there were any
255        non-matching lines.
257    14. Added --file-offsets and --line-offsets to pcregrep.
259    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
260        infinitely looping recursion. The bug was that positive lookaheads were not
261        being skipped when checking for a possible empty match (negative lookaheads
262        and both kinds of lookbehind were skipped).
264    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
265        inclusion of <windows.h> to before rather than after the definition of
266        INVALID_FILE_ATTRIBUTES (patch from David Byron).
268    17. Specifying a possessive quantifier with a specific limit for a Unicode
269        character property caused pcre_compile() to compile bad code, which led at
270        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
271        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
272        caused the error; without that there was no problem.
274    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
276    19. Added --enable-pcretest-libreadline.
278    20. In pcrecpp.cc, the variable 'count' was incremented twice in
279        RE::GlobalReplace(). As a result, the number of replacements returned was
280        double what it should be. I removed one of the increments, but Craig sent a
281        later patch that removed the other one (the right fix) and added unit tests
282        that check the return values (which was not done before).
284    21. Several CMake things:
286        (1) Arranged that, when cmake is used on Unix, the libraries end up with
287            the names libpcre and libpcreposix, not just pcre and pcreposix.
289        (2) The above change means that pcretest and pcregrep are now correctly
290            linked with the newly-built libraries, not previously installed ones.
294    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
295        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
296        UTF-8 newline character). The key issue is that the pattern starts .*;
297        this means that the match must be either at the beginning, or after a
298        newline. The bug was in the code for advancing after a failed match and
299        checking that the new position followed a newline. It was not taking
300        account of UTF-8 characters correctly.
302    23. PCRE was behaving differently from Perl in the way it recognized POSIX
303        character classes. PCRE was not treating the sequence [:...:] as a
304        character class unless the ... were all letters. Perl, however, seems to
305        allow any characters between [: and :], though of course it rejects as
306        unknown any "names" that contain non-letters, because all the known class
307        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
308        for example, whereas PCRE did not - it did not recognize a POSIX character
309        class. This seemed a bit dangerous, so the code has been changed to be
310        closer to Perl. The behaviour is not identical to Perl, because PCRE will
311        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
312        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
313        Perl does, and where it didn't before.
315    24. Rewrite so as to remove the single use of %n from pcregrep because in some
316        Windows environments %n is disabled by default.
319    Version 7.4 21-Sep-07
320    ---------------------
322    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
323        means that a class such as [\s] counted as "explicit reference to CR or
324        LF". That isn't really right - the whole point of the change was to try to
325        help when there was an actual mention of one of the two characters. So now
326        the change happens only if \r or \n (or a literal CR or LF) character is
327        encountered.
329    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
330        of both had grown to the point where there were only 3 bits left.
331        Fortunately, there was spare space in the data structure, and so I have
332        moved the internal flags into a new 16-bit field to free up more option
333        bits.
335    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
336        but did not set the internal JCHANGED flag - either of these is enough to
337        control the way the "get" function works - but the PCRE_INFO_JCHANGED
338        facility is supposed to tell if (?J) was ever used, so now (?J) at the
339        start sets both bits.
341    4.  Added options (at build time, compile time, exec time) to change \R from
342        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
344    5.  doc/pcresyntax.html was missing from the distribution.
346    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
347        compatibility, even though it is no longer used.
349    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
350        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
351        windows.h file is present (where different names are used). [This was
352        reversed later after testing - see 16 below.]
354    8.  Changed all #include <config.h> to #include "config.h". There were also
355        some further <pcre.h> cases that I changed to "pcre.h".
357    9.  When pcregrep was used with the --colour option, it missed the line ending
358        sequence off the lines that it output.
360    10. It was pointed out to me that arrays of string pointers cause lots of
361        relocations when a shared library is dynamically loaded. A technique of
362        using a single long string with a table of offsets can drastically reduce
363        these. I have refactored PCRE in four places to do this. The result is
364        dramatic:
366          Originally:                          290
367          After changing UCP table:            187
368          After changing error message table:   43
369          After changing table of "verbs"       36
370          After changing table of Posix names   22
372        Thanks to the folks working on Gregex for glib for this insight.
374    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
375        unicode-properties was also set.
377    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
379    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
380        checked only for CRLF.
382    14. Added casts to pcretest.c to avoid compiler warnings.
384    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
386    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
387        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
388        entirely. This removes changes made in 7 above.
390    17. The CMake files have been updated, and there is now more information about
391        building with CMake in the NON-UNIX-USE document.
394    Version 7.3 28-Aug-07
395    ---------------------
397     1. In the rejigging of the build system that eventually resulted in 7.1, the
398        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
399        brackets there is not right, since it causes compilers to look for an
400        installed pcre.h, not the version that is in the source that is being
401        compiled (which of course may be different). I have changed it back to:
403          #include "pcre.h"
405        I have a vague recollection that the change was concerned with compiling in
406        different directories, but in the new build system, that is taken care of
407        by the VPATH setting the Makefile.
409     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
410        when the subject happened to end in the byte 0x85 (e.g. if the last
411        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
412        characters but of course it shouldn't be taken as a newline when it is part
413        of another character. The bug was that, for an unlimited repeat of . in
414        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
415        characters when looking for a newline.
417     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
419     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
420        in debug output.
422     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
423        long printing in the pcrecpp unittest when running under MinGW.
425     6. ESC_K was left out of the EBCDIC table.
427     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
428        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
429        limit also applies to "virtual nesting" when a pattern is recursive, and in
430        this case 1000 isn't so big. I have been able to remove this limit at the
431        expense of backing off one optimization in certain circumstances. Normally,
432        when pcre_exec() would call its internal match() function recursively and
433        immediately return the result unconditionally, it uses a "tail recursion"
434        feature to save stack. However, when a subpattern that can match an empty
435        string has an unlimited repetition quantifier, it no longer makes this
436        optimization. That gives it a stack frame in which to save the data for
437        checking that an empty string has been matched. Previously this was taken
438        from the 1000-entry workspace that had been reserved. So now there is no
439        explicit limit, but more stack is used.
441     8. Applied Daniel's patches to solve problems with the import/export magic
442        syntax that is required for Windows, and which was going wrong for the
443        pcreposix and pcrecpp parts of the library. These were overlooked when this
444        problem was solved for the main library.
446     9. There were some crude static tests to avoid integer overflow when computing
447        the size of patterns that contain repeated groups with explicit upper
448        limits. As the maximum quantifier is 65535, the maximum group length was
449        set at 30,000 so that the product of these two numbers did not overflow a
450        32-bit integer. However, it turns out that people want to use groups that
451        are longer than 30,000 bytes (though not repeat them that many times).
452        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
453        made it possible to implement the integer overflow checks in a much more
454        dynamic way, which I have now done. The artificial limitation on group
455        length has been removed - we now have only the limit on the total length of
456        the compiled pattern, which depends on the LINK_SIZE setting.
458    10. Fixed a bug in the documentation for get/copy named substring when
459        duplicate names are permitted. If none of the named substrings are set, the
460        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
461        empty string.
463    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
464        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
465        because the ] is interpreted as the first data character and the
466        terminating ] is not found. PCRE has been made compatible with Perl in this
467        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
468        cause memory overwriting.
470    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
471        string has been matched (to stop an infinite loop). It was not recognizing
472        a conditional subpattern that could match an empty string if that
473        subpattern was within another subpattern. For example, it looped when
474        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
475        condition was not nested. This bug has been fixed.
477    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
478        past the start of the subject in the presence of bytes with the top bit
479        set, for example "\x8aBCD".
481    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
482        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
484    14. Optimized (?!) to (*FAIL).
486    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
487        This restricts code points to be within the range 0 to 0x10FFFF, excluding
488        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
489        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
490        does: it's just the validity check that is more restrictive.
492    16. Inserted checks for integer overflows during escape sequence (backslash)
493        processing, and also fixed erroneous offset values for syntax errors during
494        backslash processing.
496    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
497        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
499    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
500        caused an overrun.
502    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
503        something other than just ASCII characters) inside a group that had an
504        unlimited repeat caused a loop at compile time (while checking to see
505        whether the group could match an empty string).
507    20. Debugging a pattern containing \p or \P could cause a crash. For example,
508        [\P{Any}] did so. (Error in the code for printing property names.)
510    21. An orphan \E inside a character class could cause a crash.
512    22. A repeated capturing bracket such as (A)? could cause a wild memory
513        reference during compilation.
515    23. There are several functions in pcre_compile() that scan along a compiled
516        expression for various reasons (e.g. to see if it's fixed length for look
517        behind). There were bugs in these functions when a repeated \p or \P was
518        present in the pattern. These operators have additional parameters compared
519        with \d, etc, and these were not being taken into account when moving along
520        the compiled data. Specifically:
522        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
523            length.
525        (b) An item such as \pL+ within a repeated group could cause crashes or
526            loops.
528        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
529            "reference to non-existent subpattern" error.
531        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
533    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
534        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
536    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
538    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
539        character were causing crashes (broken optimization).
541    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
542        \p or \P) caused a compile-time loop.
544    28. More problems have arisen in unanchored patterns when CRLF is a valid line
545        break. For example, the unstudied pattern [\r\n]A does not match the string
546        "\r\nA" because change 7.0/46 below moves the current point on by two
547        characters after failing to match at the start. However, the pattern \nA
548        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
549        the same is true. There doesn't seem any very clean way out of this, but
550        what I have chosen to do makes the common cases work: PCRE now takes note
551        of whether there can be an explicit match for \r or \n anywhere in the
552        pattern, and if so, 7.0/46 no longer applies. As part of this change,
553        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
554        pattern has explicit CR or LF references.
556    29. Added (*CR) etc for changing newline setting at start of pattern.
559    Version 7.2 19-Jun-07
560    ---------------------
562     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
563        which is apparently normally available under Windows.
565     2. Re-jig the pcregrep tests with different newline settings in an attempt
566        to make them independent of the local environment's newline setting.
568     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
570     4. Some of the "internals" tests were previously cut out when the link size
571        was not 2, because the output contained actual offsets. The recent new
572        "Z" feature of pcretest means that these can be cut out, making the tests
573        usable with all link sizes.
575     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
576        stack recursion. This gives a massive performance boost under BSD, but just
577        a small improvement under Linux. However, it saves one field in the frame
578        in all cases.
580     6. Added more features from the forthcoming Perl 5.10:
582        (a) (?-n) (where n is a string of digits) is a relative subroutine or
583            recursion call. It refers to the nth most recently opened parentheses.
585        (b) (?+n) is also a relative subroutine call; it refers to the nth next
586            to be opened parentheses.
588        (c) Conditions that refer to capturing parentheses can be specified
589            relatively, for example, (?(-2)... or (?(+3)...
591        (d) \K resets the start of the current match so that everything before
592            is not part of it.
594        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
596        (f) \g{name} is another synonym - part of Perl 5.10's unification of
597            reference syntax.
599        (g) (?| introduces a group in which the numbering of parentheses in each
600            alternative starts with the same number.
602        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
604     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
607     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
608        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
609        for detecting groups that can match an empty string.
611     9. A pattern with a very large number of alternatives (more than several
612        hundred) was running out of internal workspace during the pre-compile
613        phase, where pcre_compile() figures out how much memory will be needed. A
614        bit of new cunning has reduced the workspace needed for groups with
615        alternatives. The 1000-alternative test pattern now uses 12 bytes of
616        workspace instead of running out of the 4096 that are available.
618    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
620    11. Applied patch from Google to remove an optimization that didn't quite work.
621        The report of the bug said:
623          pcrecpp::RE("a*").FullMatch("aaa") matches, while
624          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
625          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
627    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
628        it matched the wrong number of bytes.
631    Version 7.1 24-Apr-07
632    ---------------------
634     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
635        that is more "standard", making use of automake and other Autotools. There
636        is some re-arrangement of the files and adjustment of comments consequent
637        on this.
639     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
640        for recursive directory scanning broke on some systems because the files
641        are not scanned in any specific order and on different systems the order
642        was different. A call to "sort" has been inserted into RunGrepTest for the
643        approprate test as a short-term fix. In the longer term there may be an
644        alternative.
646     3. I had an email from Eric Raymond about problems translating some of PCRE's
647        man pages to HTML (despite the fact that I distribute HTML pages, some
648        people do their own conversions for various reasons). The problems
649        concerned the use of low-level troff macros .br and .in. I have therefore
650        removed all such uses from the man pages (some were redundant, some could
651        be replaced by .nf/.fi pairs). The 132html script that I use to generate
652        HTML has been updated to handle .nf/.fi and to complain if it encounters
653        .br or .in.
655     4. Updated comments in configure.ac that get placed in config.h.in and also
656        arranged for config.h to be included in the distribution, with the name
657        config.h.generic, for the benefit of those who have to compile without
658        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
660     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
661        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
662        makevp.bat for the current PCRE, using the additional files
663        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
665     6. A Windows user reported a minor discrepancy with test 2, which turned out
666        to be caused by a trailing space on an input line that had got lost in his
667        copy. The trailing space was an accident, so I've just removed it.
669     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
670        that is needed.
672     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
673        as "const" (a) because they are and (b) because it helps the PHP
674        maintainers who have recently made a script to detect big data structures
675        in the php code that should be moved to the .rodata section. I remembered
676        to update Builducptable as well, so it won't revert if ucptable.h is ever
677        re-created.
679     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
680        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
681        order to be able to cut out the UTF-8 tables in the latter when UTF-8
682        support is not required. This saves 1.5-2K of code, which is important in
683        some applications.
685        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
686        so as not to refer to the tables, even though these functions will never be
687        called when UTF-8 support is disabled. Otherwise there are problems with a
688        shared library.
690    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
692        (a) It was defining its arguments as char * instead of void *.
694        (b) It was assuming that all moves were upwards in memory; this was true
695            a long time ago when I wrote it, but is no longer the case.
697        The emulated memove() is provided for those environments that have neither
698        memmove() nor bcopy(). I didn't think anyone used it these days, but that
699        is clearly not the case, as these two bugs were recently reported.
701    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
702        and Detrail to create the HTML documentation, the .txt form of the man
703        pages, and it removes trailing spaces from listed files. It also creates
704        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
705        case, it wraps all the #defines with #ifndefs. This script should be run
706        before "make dist".
708    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
709        with Unicode property support.
711        (a) For a maximizing quantifier, if the two different cases of the
712            character were of different lengths in their UTF-8 codings (there are
713            some cases like this - I found 11), and the matching function had to
714            back up over a mixture of the two cases, it incorrectly assumed they
715            were both the same length.
717        (b) When PCRE was configured to use the heap rather than the stack for
718            recursion during matching, it was not correctly preserving the data for
719            the other case of a UTF-8 character when checking ahead for a match
720            while processing a minimizing repeat. If the check also involved
721            matching a wide character, but failed, corruption could cause an
722            erroneous result when trying to check for a repeat of the original
723            character.
725    13. Some tidying changes to the testing mechanism:
727        (a) The RunTest script now detects the internal link size and whether there
728            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
729            values substituted by "configure". (The RunGrepTest script already did
730            this for UTF-8.) The configure.ac script no longer substitutes the
731            relevant variables.
733        (b) The debugging options /B and /D in pcretest show the compiled bytecode
734            with length and offset values. This means that the output is different
735            for different internal link sizes. Test 2 is skipped for link sizes
736            other than 2 because of this, bypassing the problem. Unfortunately,
737            there was also a test in test 3 (the locale tests) that used /B and
738            failed for link sizes other than 2. Rather than cut the whole test out,
739            I have added a new /Z option to pcretest that replaces the length and
740            offset values with spaces. This is now used to make test 3 independent
741            of link size. (Test 2 will be tidied up later.)
743    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
744        segmentation fault instead of returning the appropriate error message.
746    15. In multiline mode when the newline sequence was set to "any", the pattern
747        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
748        This doesn't seem right; it now treats the CRLF combination as the line
749        ending, and so does not match in that case. It's only a pattern such as ^$
750        that would hit this one: something like ^ABC$ would have failed after \r
751        and then tried again after \r\n.
753    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
754        in an attempt to make files that differ only in their line terminators
755        compare equal. This works on Linux.
757    17. Under certain error circumstances pcregrep might try to free random memory
758        as it exited. This is now fixed, thanks to valgrind.
760    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
761        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
762        was because its rules for how to advance for /g after matching an empty
763        string at the end of a line did not allow for this case. They now check for
764        it specially.
766    20. pcretest is supposed to handle patterns and data of any length, by
767        extending its buffers when necessary. It was getting this wrong when the
768        buffer for a data line had to be extended.
770    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
771        CRLF as a newline sequence.
773    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
774        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
775        I have nevertheless tidied it up.
777    23. Added some casts to kill warnings from HP-UX ia64 compiler.
779    24. Added a man page for pcre-config.
782    Version 7.0 19-Dec-06
783    ---------------------
785     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
786        moving to gcc 4.1.1.
788     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
789        sys/time.h, which is documented as needed for this function. It doesn't
790        seem to matter on Linux, but it showed up on some releases of OS X.
792     3. It seems that there are systems where bytes whose values are greater than
793        127 match isprint() in the "C" locale. The "C" locale should be the
794        default when a C program starts up. In most systems, only ASCII printing
795        characters match isprint(). This difference caused the output from pcretest
796        to vary, making some of the tests fail. I have changed pcretest so that:
798        (a) When it is outputting text in the compiled version of a pattern, bytes
799            other than 32-126 are always shown as hex escapes.
801        (b) When it is outputting text that is a matched part of a subject string,
802            it does the same, unless a different locale has been set for the match
803            (using the /L modifier). In this case, it uses isprint() to decide.
805     4. Fixed a major bug that caused incorrect computation of the amount of memory
806        required for a compiled pattern when options that changed within the
807        pattern affected the logic of the preliminary scan that determines the
808        length. The relevant options are -x, and -i in UTF-8 mode. The result was
809        that the computed length was too small. The symptoms of this bug were
810        either the PCRE error "internal error: code overflow" from pcre_compile(),
811        or a glibc crash with a message such as "pcretest: free(): invalid next
812        size (fast)". Examples of patterns that provoked this bug (shown in
813        pcretest format) are:
815          /(?-x: )/x
816          /(?x)(?-x: \s*#\s*)/
817          /((?i)[\x{c0}])/8
818          /(?i:[\x{c0}])/8
820        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
821        is now done differently.
823     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
824        wrapper classes; (b) implement a new function in the C++ scanner that is
825        more efficient than the old way of doing things because it avoids levels of
826        recursion in the regex matching; (c) add a paragraph to the documentation
827        for the FullMatch() function.
829     6. The escape sequence \n was being treated as whatever was defined as
830        "newline". Not only was this contrary to the documentation, which states
831        that \n is character 10 (hex 0A), but it also went horribly wrong when
832        "newline" was defined as CRLF. This has been fixed.
834     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
835        was being set to -1 for the "end of line" case (supposedly a value that no
836        character can have). Though this value is never used (the check for end of
837        line is "zero bytes in current character"), it caused compiler complaints.
838        I've changed it to 0xffffffff.
840     8. In pcre_version.c, the version string was being built by a sequence of
841        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
842        string (as it is for production releases) called a macro with an empty
843        argument. The C standard says the result of this is undefined. The gcc
844        compiler treats it as an empty string (which was what was wanted) but it is
845        reported that Visual C gives an error. The source has been hacked around to
846        avoid this problem.
848     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
849        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
850        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
851        of them did).
853    10. Originally, pcretest opened its input and output without "b"; then I was
854        told that "b" was needed in some environments, so it was added for release
855        5.0 to both the input and output. (It makes no difference on Unix-like
856        systems.) Later I was told that it is wrong for the input on Windows. I've
857        now abstracted the modes into two macros, to make it easier to fiddle with
858        them, and removed "b" from the input mode under Windows.
860    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
862    12. Added -help and --help to pcretest as an official way of being reminded
863        of the options.
865    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
866        and pcrecpp.cc because they annoy compilers at high warning levels.
868    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
870    15. Fixed an occurrence of == in configure.ac that should have been = (shell
871        scripts are not C programs :-) and which was not noticed because it works
872        on Linux.
874    16. pcretest is supposed to handle any length of pattern and data line (as one
875        line or as a continued sequence of lines) by extending its input buffer if
876        necessary. This feature was broken for very long pattern lines, leading to
877        a string of junk being passed to pcre_compile() if the pattern was longer
878        than about 50K.
880    17. I have done a major re-factoring of the way pcre_compile() computes the
881        amount of memory needed for a compiled pattern. Previously, there was code
882        that made a preliminary scan of the pattern in order to do this. That was
883        OK when PCRE was new, but as the facilities have expanded, it has become
884        harder and harder to keep it in step with the real compile phase, and there
885        have been a number of bugs (see for example, 4 above). I have now found a
886        cunning way of running the real compile function in a "fake" mode that
887        enables it to compute how much memory it would need, while actually only
888        ever using a few hundred bytes of working memory and without too many
889        tests of the mode. This should make future maintenance and development
890        easier. A side effect of this work is that the limit of 200 on the nesting
891        depth of parentheses has been removed (though this was never a serious
892        limitation, I suspect). However, there is a downside: pcre_compile() now
893        runs more slowly than before (30% or more, depending on the pattern). I
894        hope this isn't a big issue. There is no effect on runtime performance.
896    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
897        newline (only possible for the last line of a file) and it was a
898        pattern that set a locale (followed by /Lsomething), pcretest crashed.
900    19. Added additional timing features to pcretest. (1) The -tm option now times
901        matching only, not compiling. (2) Both -t and -tm can be followed, as a
902        separate command line item, by a number that specifies the number of
903        repeats to use when timing. The default is 50000; this gives better
904        precision, but takes uncomfortably long for very large patterns.
906    20. Extended pcre_study() to be more clever in cases where a branch of a
907        subpattern has no definite first character. For example, (a*|b*)[cd] would
908        previously give no result from pcre_study(). Now it recognizes that the
909        first character must be a, b, c, or d.
911    21. There was an incorrect error "recursive call could loop indefinitely" if
912        a subpattern (or the entire pattern) that was being tested for matching an
913        empty string contained only one non-empty item after a nested subpattern.
914        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
915        incorrectly, because the \d was being skipped in the check.
917    22. The pcretest program now has a new pattern option /B and a command line
918        option -b, which is equivalent to adding /B to every pattern. This causes
919        it to show the compiled bytecode, without the additional information that
920        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
921        is the same as /B/I).
923    23. A new optimization is now able automatically to treat some sequences such
924        as a*b as a*+b. More specifically, if something simple (such as a character
925        or a simple class like \d) has an unlimited quantifier, and is followed by
926        something that cannot possibly match the quantified thing, the quantifier
927        is automatically "possessified".
929    24. A recursive reference to a subpattern whose number was greater than 39
930        went wrong under certain circumstances in UTF-8 mode. This bug could also
931        have affected the operation of pcre_study().
933    25. Realized that a little bit of performance could be had by replacing
934        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
936    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
938    27. Possessive quantifiers such as a++ were previously implemented by turning
939        them into atomic groups such as ($>a+). Now they have their own opcodes,
940        which improves performance. This includes the automatically created ones
941        from 23 above.
943    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
944        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
945        the first matched character to be a colon. This applied both to named and
946        numbered groups.
948    29. The ucpinternal.h header file was missing its idempotency #ifdef.
950    30. I was sent a "project" file called libpcre.a.dev which I understand makes
951        building PCRE on Windows easier, so I have included it in the distribution.
953    31. There is now a check in pcretest against a ridiculously large number being
954        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
955        loop, the loop is abandoned.
957    32. Forward references to subpatterns in conditions such as (?(2)...) where
958        subpattern 2 is defined later cause pcre_compile() to search forwards in
959        the pattern for the relevant set of parentheses. This search went wrong
960        when there were unescaped parentheses in a character class, parentheses
961        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
963    33. "Subroutine" calls and backreferences were previously restricted to
964        referencing subpatterns earlier in the regex. This restriction has now
965        been removed.
967    34. Added a number of extra features that are going to be in Perl 5.10. On the
968        whole, these are just syntactic alternatives for features that PCRE had
969        previously implemented using the Python syntax or my own invention. The
970        other formats are all retained for compatibility.
972        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
973            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
974            also .NET compatible.
976        (b) A recursion or subroutine call to a named group can now be defined as
977            (?&name) as well as (?P>name).
979        (c) A backreference to a named group can now be defined as \k<name> or
980            \k'name' as well as (?P=name). The new forms, as well as being in Perl
981            5.10, are also .NET compatible.
983        (d) A conditional reference to a named group can now use the syntax
984            (?(<name>) or (?('name') as well as (?(name).
986        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
987            groups (named and numbered) that are never evaluated inline, but can be
988            called as "subroutines" from elsewhere. In effect, the DEFINE condition
989            is always false. There may be only one alternative in such a group.
991        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
992            as the simple (?(R). The condition is true only if the most recent
993            recursion is that of the given number or name. It does not search out
994            through the entire recursion stack.
996        (g) The escape \gN or \g{N} has been added, where N is a positive or
997            negative number, specifying an absolute or relative reference.
999    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1000        some "unreachable code" warnings.
1002    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1003        things, this adds five new scripts.
1005    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1006        There were also incompatibilities regarding the handling of \Q..\E inside
1007        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1008        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1010    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1011        matches an empty string, and forcibly breaks the loop. There were bugs in
1012        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1013        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1014        separate and independent bugs (that affected different cases) have been
1015        fixed.
1017    39. Refactored the code to abolish the use of different opcodes for small
1018        capturing bracket numbers. This is a tidy that I avoided doing when I
1019        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1020        The new approach is not only tidier, it makes it possible to reduce the
1021        memory needed to fix the previous bug (38).
1023    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1024        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1025        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1026        mode.
1028    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1029        report.
1031    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1032        copy construction and assignment in the C++ wrapper.
1034    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1035        couple of bugs that could have given wrong results in the "--newline=crlf"
1036        case.
1038    44. Added a number of casts and did some reorganization of signed/unsigned int
1039        variables following suggestions from Dair Grant. Also renamed the variable
1040        "this" as "item" because it is a C++ keyword.
1042    45. Arranged for dftables to add
1044          #include "pcre_internal.h"
1046        to pcre_chartables.c because without it, gcc 4.x may remove the array
1047        definition from the final binary if PCRE is built into a static library and
1048        dead code stripping is activated.
1050    46. For an unanchored pattern, if a match attempt fails at the start of a
1051        newline sequence, and the newline setting is CRLF or ANY, and the next two
1052        characters are CRLF, advance by two characters instead of one.
1055    Version 6.7 04-Jul-06
1056    ---------------------
1058     1. In order to handle tests when input lines are enormously long, pcretest has
1059        been re-factored so that it automatically extends its buffers when
1060        necessary. The code is crude, but this _is_ just a test program. The
1061        default size has been increased from 32K to 50K.
1063     2. The code in pcre_study() was using the value of the re argument before
1064        testing it for NULL. (Of course, in any sensible call of the function, it
1065        won't be NULL.)
1067     3. The memmove() emulation function in pcre_internal.h, which is used on
1068        systems that lack both memmove() and bcopy() - that is, hardly ever -
1069        was missing a "static" storage class specifier.
1071     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1072        containing an extended class (one that cannot be represented by a bitmap
1073        because it contains high-valued characters or Unicode property items, e.g.
1074        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1075        pattern, but PCRE should not loop if you do not (it no longer does).
1076        [Detail: two cases were found: (a) a repeated subpattern containing an
1077        extended class; (b) a recursive reference to a subpattern that followed a
1078        previous extended class. It wasn't skipping over the extended class
1079        correctly when UTF-8 mode was not set.]
1081     5. A negated single-character class was not being recognized as fixed-length
1082        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1083        compile error "lookbehind assertion is not fixed length".
1085     6. The RunPerlTest auxiliary script was showing an unexpected difference
1086        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1087        write a Perl script that can interpret lines of an input file either as
1088        byte characters or as UTF-8, which is what "perltest" was being required to
1089        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1090        can't do is switch easily at run time between having the "use utf8;" pragma
1091        or not. In the end, I fudged it by using the RunPerlTest script to insert
1092        "use utf8;" explicitly for the UTF-8 tests.
1094     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1095        the end of the subject string, contrary to the documentation and to what
1096        Perl does. This was true of both matching functions. Now it matches only at
1097        the start of the subject and immediately after *internal* newlines.
1099     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1100        a pointer to an int instead of a pointer to an unsigned long int. This
1101        caused problems on 64-bit systems.
1103     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1104        instance of the 'standard' template library not being so standard".
1106    10. There was no check on the number of named subpatterns nor the maximum
1107        length of a subpattern name. The product of these values is used to compute
1108        the size of the memory block for a compiled pattern. By supplying a very
1109        long subpattern name and a large number of named subpatterns, the size
1110        computation could be caused to overflow. This is now prevented by limiting
1111        the length of names to 32 characters, and the number of named subpatterns
1112        to 10,000.
1114    11. Subpatterns that are repeated with specific counts have to be replicated in
1115        the compiled pattern. The size of memory for this was computed from the
1116        length of the subpattern and the repeat count. The latter is limited to
1117        65535, but there was no limit on the former, meaning that integer overflow
1118        could in principle occur. The compiled length of a repeated subpattern is
1119        now limited to 30,000 bytes in order to prevent this.
1121    12. Added the optional facility to have named substrings with the same name.
1123    13. Added the ability to use a named substring as a condition, using the
1124        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1125        are numbers (not recommended). Forward references are permitted.
1127    14. Added forward references in named backreferences (if you see what I mean).
1129    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1130        pattern could run off the end of the subject. For example, the pattern
1131        "(?s)(.{1,5})"8 did this with the subject "ab".
1133    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1134        PCRE_CASELESS was set when matching characters that were quantified with ?
1135        or *.
1137    17. A character class other than a single negated character that had a minimum
1138        but no maximum quantifier - for example [ab]{6,} - was not handled
1139        correctly by pce_dfa_exec(). It would match only one character.
1141    18. A valid (though odd) pattern that looked like a POSIX character
1142        class but used an invalid character after [ (for example [[,abc,]]) caused
1143        pcre_compile() to give the error "Failed: internal error: code overflow" or
1144        in some cases to crash with a glibc free() error. This could even happen if
1145        the pattern terminated after [[ but there just happened to be a sequence of
1146        letters, a binary zero, and a closing ] in the memory that followed.
1148    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1149        over the years. Originally (before any Unicode support), just the bottom 8
1150        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1151        output from "man perlunicode" includes this:
1153          The regular expression compiler produces polymorphic opcodes.  That
1154          is, the pattern adapts to the data and automatically switches to
1155          the Unicode character scheme when presented with Unicode data--or
1156          instead uses a traditional byte scheme when presented with byte
1157          data.
1159        Sadly, a wide octal escape does not cause a switch, and in a string with
1160        no other multibyte characters, these octal escapes are treated as before.
1161        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1162        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1163        Unicode string.
1165        I have not perpetrated such confusion in PCRE. Up till now, it took just
1166        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1167        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1168        translate to the appropriate multibyte character.
1170    29. Applied some refactoring to reduce the number of warnings from Microsoft
1171        and Borland compilers. This has included removing the fudge introduced
1172        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1173        a warning about an unused variable.
1175    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1176        characters since release 4.0, because Perl (from release 5.004) does not.
1177        [Or at least, is documented not to: some releases seem to be in conflict
1178        with the documentation.] However, when a pattern was studied with
1179        pcre_study() and all its branches started with \s, PCRE still included VT
1180        as a possible starting character. Of course, this did no harm; it just
1181        caused an unnecessary match attempt.
1183    22. Removed a now-redundant internal flag bit that recorded the fact that case
1184        dependency changed within the pattern. This was once needed for "required
1185        byte" processing, but is no longer used. This recovers a now-scarce options
1186        bit. Also moved the least significant internal flag bit to the most-
1187        significant bit of the word, which was not previously used (hangover from
1188        the days when it was an int rather than a uint) to free up another bit for
1189        the future.
1191    23. Added support for CRLF line endings as well as CR and LF. As well as the
1192        default being selectable at build time, it can now be changed at runtime
1193        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1194        specify that it is scanning data with non-default line endings.
1196    24. Changed the definition of CXXLINK to make it agree with the definition of
1197        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1199    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1200        recursions. This makes a big different to stack usage for some patterns.
1202    26. If a subpattern containing a named recursion or subroutine reference such
1203        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1204        the space required for the compiled pattern went wrong and gave too small a
1205        value. Depending on the environment, this could lead to "Failed: internal
1206        error: code overflow at offset 49" or "glibc detected double free or
1207        corruption" errors.
1209    27. Applied patches from Google (a) to support the new newline modes and (b) to
1210        advance over multibyte UTF-8 characters in GlobalReplace.
1212    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1213        difference for some implementation of PCRE in some Windows version.
1215    29. Added some extra testing facilities to pcretest:
1217        \q<number>   in a data line sets the "match limit" value
1218        \Q<number>   in a data line sets the "match recursion limt" value
1219        -S <number>  sets the stack size, where <number> is in megabytes
1221        The -S option isn't available for Windows.
1224    Version 6.6 06-Feb-06
1225    ---------------------
1227     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1228        in pcreposix.h. I have copied the definition from pcre.h.
1230     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1231        because pcre.h is no longer a built file.
1233     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1234        not normally included in the compiled code.
1237    Version 6.5 01-Feb-06
1238    ---------------------
1240     1. When using the partial match feature with pcre_dfa_exec(), it was not
1241        anchoring the second and subsequent partial matches at the new starting
1242        point. This could lead to incorrect results. For example, with the pattern
1243        /1234/, partially matching against "123" and then "a4" gave a match.
1245     2. Changes to pcregrep:
1247        (a) All non-match returns from pcre_exec() were being treated as failures
1248            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1249            error message is output. Some extra information is given for the
1250            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1251            probably the only errors that are likely to be caused by users (by
1252            specifying a regex that has nested indefinite repeats, for instance).
1253            If there are more than 20 of these errors, pcregrep is abandoned.
1255        (b) A binary zero was treated as data while matching, but terminated the
1256            output line if it was written out. This has been fixed: binary zeroes
1257            are now no different to any other data bytes.
1259        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1260            used to set a locale for matching. The --locale=xxxx long option has
1261            been added (no short equivalent) to specify a locale explicitly on the
1262            pcregrep command, overriding the environment variables.
1264        (d) When -B was used with -n, some line numbers in the output were one less
1265            than they should have been.
1267        (e) Added the -o (--only-matching) option.
1269        (f) If -A or -C was used with -c (count only), some lines of context were
1270            accidentally printed for the final match.
1272        (g) Added the -H (--with-filename) option.
1274        (h) The combination of options -rh failed to suppress file names for files
1275            that were found from directory arguments.
1277        (i) Added the -D (--devices) and -d (--directories) options.
1279        (j) Added the -F (--fixed-strings) option.
1281        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1283        (l) Added the --colo(u)r option.
1285        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1286            is not present by default.
1288     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1289        items such as (?R) or (?1), when the recursion could match a number of
1290        alternatives. If it matched one of the alternatives, but subsequently,
1291        outside the recursion, there was a failure, the code tried to back up into
1292        the recursion. However, because of the way PCRE is implemented, this is not
1293        possible, and the result was an incorrect result from the match.
1295        In order to prevent this happening, the specification of recursion has
1296        been changed so that all such subpatterns are automatically treated as
1297        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1299     4. I had overlooked the fact that, in some locales, there are characters for
1300        which isalpha() is true but neither isupper() nor islower() are true. In
1301        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1302        and ordfeminine) are like this. This affected the treatment of \w and \W
1303        when they appeared in character classes, but not when they appeared outside
1304        a character class. The bit map for "word" characters is now created
1305        separately from the results of isalnum() instead of just taking it from the
1306        upper, lower, and digit maps. (Plus the underscore character, of course.)
1308     5. The above bug also affected the handling of POSIX character classes such as
1309        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1310        permanent tables. Instead, the bit maps for such a class were previously
1311        created as the appropriate unions of the upper, lower, and digit bitmaps.
1312        Now they are created by subtraction from the [[:word:]] class, which has
1313        its own bitmap.
1315     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1316        It is created by subtracting the vertical space characters (\x09, \x0a,
1317        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1318        subtraction was done in the overall bitmap for a character class, meaning
1319        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1320        be recognized. This bug has been fixed.
1322     7. Patches from the folks at Google:
1324          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1325          real life, but is still worth protecting against".
1327          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1328          regular expressions".
1330          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1331          have it.
1333          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1334          "configure" and the latter not, in order to fix a problem somebody had
1335          with compiling the Arg class on HP-UX.
1337          (e) Improve the error-handling of the C++ wrapper a little bit.
1339          (f) New tests for checking recursion limiting.
1341     8. The pcre_memmove() function, which is used only if the environment does not
1342        have a standard memmove() function (and is therefore rarely compiled),
1343        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1344        returning a result (though PCRE never actually uses the result).
1346     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1347        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1348        returned instead of calling malloc() with an overflowing number that would
1349        most likely cause subsequent chaos.
1351    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1353    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1354        with this option is matched, the nmatch and pmatch options of regexec() are
1355        ignored.
1357    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1358        provided in case anyone wants to the the POSIX interface with UTF-8
1359        strings.
1361    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1362        C++ linking (needed for some HP-UX environments).
1364    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1365        (unused parameter) and in the pcre_printint() function (omitted "default"
1366        switch label when the default is to do nothing).
1368    15. Added some code to make it possible, when PCRE is compiled as a C++
1369        library, to replace subject pointers for pcre_exec() with a smart pointer
1370        class, thus making it possible to process discontinuous strings.
1372    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1373        much the same function. They were added by different people who were trying
1374        to make PCRE easy to compile on non-Unix systems. It has been suggested
1375        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1376        for compiling on Windows systems. I have therefore replaced it with
1377        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1378        defaults to "extern" for C or "extern C" for C++, which works fine on
1379        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1380        SCOPE with something explicit in config.h. In addition:
1382        (a) pcreposix.h still had just "extern" instead of either of these macros;
1383            I have replaced it with PCRE_DATA_SCOPE.
1385        (b) Functions such as _pcre_xclass(), which are internal to the library,
1386            but external in the C sense, all had PCRE_EXPORT in their definitions.
1387            This is apparently wrong for the Windows case, so I have removed it.
1388            (It makes no difference on Unix-like systems.)
1390    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1391        of recursive calls to match(). This is different to MATCH_LIMIT because
1392        that limits the total number of calls to match(), not all of which increase
1393        the depth of recursion. Limiting the recursion depth limits the amount of
1394        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1395        when PCRE is compiled, and changed at run time. A patch from Google adds
1396        this functionality to the C++ interface.
1398    18. Changes to the handling of Unicode character properties:
1400        (a) Updated the table to Unicode 4.1.0.
1402        (b) Recognize characters that are not in the table as "Cn" (undefined).
1404        (c) I revised the way the table is implemented to a much improved format
1405            which includes recognition of ranges. It now supports the ranges that
1406            are defined in UnicodeData.txt, and it also amalgamates other
1407            characters into ranges. This has reduced the number of entries in the
1408            table from around 16,000 to around 3,000, thus reducing its size
1409            considerably. I realized I did not need to use a tree structure after
1410            all - a binary chop search is just as efficient. Having reduced the
1411            number of entries, I extended their size from 6 bytes to 8 bytes to
1412            allow for more data.
1414        (d) Added support for Unicode script names via properties such as \p{Han}.
1416    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1417        matching that character.
1419    20. When matching a repeated Unicode property with a minimum greater than zero,
1420        (for example \pL{2,}), PCRE could look past the end of the subject if it
1421        reached it while seeking the minimum number of characters. This could
1422        happen only if some of the characters were more than one byte long, because
1423        there is a check for at least the minimum number of bytes.
1425    21. Refactored the implementation of \p and \P so as to be more general, to
1426        allow for more different types of property in future. This has changed the
1427        compiled form incompatibly. Anybody with saved compiled patterns that use
1428        \p or \P will have to recompile them.
1430    22. Added "Any" and "L&" to the supported property types.
1432    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1433        but give a compile time error if the value is greater than 0xff.
1435    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1436        accidentally not being installed or uninstalled.
1438    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1439        made were to insert the current release number. This seemed silly, because
1440        it made things harder for people building PCRE on systems that don't run
1441        "configure". I have turned pcre.h into a distributed file, no longer built
1442        by "configure", with the version identification directly included. There is
1443        no longer a pcre.h.in file.
1445        However, this change necessitated a change to the pcre-config script as
1446        well. It is built from pcre-config.in, and one of the substitutions was the
1447        release number. I have updated configure.ac so that ./configure now finds
1448        the release number by grepping pcre.h.
1450    26. Added the ability to run the tests under valgrind.
1453    Version 6.4 05-Sep-05
1454    ---------------------
1456     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1457        "--" to be printed when multiple files were scanned, even when none of the
1458        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1459        consider it to be a bug, and have restored the previous behaviour.
1461     2. A couple of code tidies to get rid of compiler warnings.
1463     3. The pcretest program used to cheat by referring to symbols in the library
1464        whose names begin with _pcre_. These are internal symbols that are not
1465        really supposed to be visible externally, and in some environments it is
1466        possible to suppress them. The cheating is now confined to including
1467        certain files from the library's source, which is a bit cleaner.
1469     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1470        file's purpose clearer.
1472     5. Reorganized pcre_ucp_findchar().
1475    Version 6.3 15-Aug-05
1476    ---------------------
1478     1. The file libpcre.pc.in did not have general read permission in the tarball.
1480     2. There were some problems when building without C++ support:
1482        (a) If C++ support was not built, "make install" and "make test" still
1483            tried to test it.
1485        (b) There were problems when the value of CXX was explicitly set. Some
1486            changes have been made to try to fix these, and ...
1488        (c) --disable-cpp can now be used to explicitly disable C++ support.
1490        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1491            backslash in a target when C++ was disabled. This confuses some
1492            versions of "make", apparently. Using an intermediate variable solves
1493            this. (Same for CPP_LOBJ.)
1495     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1496        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1497        necessary on certain architectures.
1499     4. Added a setting of -export-symbols-regex to the link command to remove
1500        those symbols that are exported in the C sense, but actually are local
1501        within the library, and not documented. Their names all begin with
1502        "_pcre_". This is not a perfect job, because (a) we have to except some
1503        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1504        available (and never for static libraries). I have made a note to try to
1505        find a way round (a) in the future.
1508    Version 6.2 01-Aug-05
1509    ---------------------
1511     1. There was no test for integer overflow of quantifier values. A construction
1512        such as {1111111111111111} would give undefined results. What is worse, if
1513        a minimum quantifier for a parenthesized subpattern overflowed and became
1514        negative, the calculation of the memory size went wrong. This could have
1515        led to memory overwriting.
1517     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1519     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1520        operating environments where this matters.
1522     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1523        PCRE options from within the C++ wrapper.
1525     5. Named capturing subpatterns were not being correctly counted when a pattern
1526        was compiled. This caused two problems: (a) If there were more than 100
1527        such subpatterns, the calculation of the memory needed for the whole
1528        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1529        back references of the form \12, where the number was greater than 9, were
1530        not recognized as back references, even though there were sufficient
1531        previous subpatterns.
1533     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1534        versions of gcc, e.g. 2.95.4.
1537    Version 6.1 21-Jun-05
1538    ---------------------
1540     1. There was one reference to the variable "posix" in pcretest.c that was not
1541        surrounded by "#if !defined NOPOSIX".
1543     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1544        the cross-check on the old pcre_info() function, for the benefit of the
1545        cut-down version of PCRE that is currently imported into Exim.
1547     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1548        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1549        patterns that start (?i) but I don't think that matters. The use of (?i) is
1550        just an example; this all applies to the other options as well.
1552     4. Since libtool seems to echo the compile commands it is issuing, the output
1553        from "make" can be reduced a bit by putting "@" in front of each libtool
1554        compile command.
1556     5. Patch from the folks at Google for configure.in to be a bit more thorough
1557        in checking for a suitable C++ installation before trying to compile the
1558        C++ stuff. This should fix a reported problem when a compiler was present,
1559        but no suitable headers.
1561     6. The man pages all had just "PCRE" as their title. I have changed them to
1562        be the relevant file name. I have also arranged that these names are
1563        retained in the file doc/pcre.txt, which is a concatenation in text format
1564        of all the man pages except the little individual ones for each function.
1566     7. The NON-UNIX-USE file had not been updated for the different set of source
1567        files that come with release 6. I also added a few comments about the C++
1568        wrapper.
1571    Version 6.0 07-Jun-05
1572    ---------------------
1574     1. Some minor internal re-organization to help with my DFA experiments.
1576     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1577        didn't matter for the library itself when fully configured, but did matter
1578        when compiling without UCP support, or within Exim, where the ucp files are
1579        not imported.
1581     3. Refactoring of the library code to split up the various functions into
1582        different source modules. The addition of the new DFA matching code (see
1583        below) to a single monolithic source would have made it really too
1584        unwieldy, quite apart from causing all the code to be include in a
1585        statically linked application, when only some functions are used. This is
1586        relevant even without the DFA addition now that patterns can be compiled in
1587        one application and matched in another.
1589        The downside of splitting up is that there have to be some external
1590        functions and data tables that are used internally in different modules of
1591        the library but which are not part of the API. These have all had their
1592        names changed to start with "_pcre_" so that they are unlikely to clash
1593        with other external names.
1595     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1596        a different (DFA) algorithm. Although it is slower than the original
1597        function, it does have some advantages for certain types of matching
1598        problem.
1600     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1601        including restarting after a partial match.
1603     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1604        defined when compiling for Windows was sent to me. I have put it into the
1605        code, though I have no means of testing or verifying it.
1607     7. Added the pcre_refcount() auxiliary function.
1609     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1610        match before or at the first newline in the subject string. In pcretest,
1611        the /f option on a pattern can be used to set this.
1613     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1614        would behave wrongly. This has been present in PCRE since release 4.0.
1616    10. A number of changes to the pcregrep command:
1618        (a) Refactored how -x works; insert ^(...)$ instead of setting
1619            PCRE_ANCHORED and checking the length, in preparation for adding
1620            something similar for -w.
1622        (b) Added the -w (match as a word) option.
1624        (c) Refactored the way lines are read and buffered so as to have more
1625            than one at a time available.
1627        (d) Implemented a pcregrep test script.
1629        (e) Added the -M (multiline match) option. This allows patterns to match
1630            over several lines of the subject. The buffering ensures that at least
1631            8K, or the rest of the document (whichever is the shorter) is available
1632            for matching (and similarly the previous 8K for lookbehind assertions).
1634        (f) Changed the --help output so that it now says
1636              -w, --word-regex(p)
1638            instead of two lines, one with "regex" and the other with "regexp"
1639            because that confused at least one person since the short forms are the
1640            same. (This required a bit of code, as the output is generated
1641            automatically from a table. It wasn't just a text change.)
1643        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1644            option but starts with a hyphen. Could be a pattern or a path name
1645            starting with a hyphen, for instance.
1647        (h) "-" can be given as a file name to represent stdin.
1649        (i) When file names are being printed, "(standard input)" is used for
1650            the standard input, for compatibility with GNU grep. Previously
1651            "<stdin>" was used.
1653        (j) The option --label=xxx can be used to supply a name to be used for
1654            stdin when file names are being printed. There is no short form.
1656        (k) Re-factored the options decoding logic because we are going to add
1657            two more options that take data. Such options can now be given in four
1658            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1660        (l) Added the -A, -B, and -C options for requesting that lines of context
1661            around matches be printed.
1663        (m) Added the -L option to print the names of files that do not contain
1664            any matching lines, that is, the complement of -l.
1666        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1667            continue to scan other files.
1669        (o) The -s option was incorrectly implemented. For compatibility with other
1670            greps, it now suppresses the error message for a non-existent or non-
1671            accessible file (but not the return code). There is a new option called
1672            -q that suppresses the output of matching lines, which was what -s was
1673            previously doing.
1675        (p) Added --include and --exclude options to specify files for inclusion
1676            and exclusion when recursing.
1678    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1679        Hopefully, it now does.
1681    12. Missing cast in pcre_study().
1683    13. Added an "uninstall" target to the makefile.
1685    14. Replaced "extern" in the function prototypes in Makefile.in with
1686        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1687        world, but is set differently for Windows.
1689    15. Added a second compiling function called pcre_compile2(). The only
1690        difference is that it has an extra argument, which is a pointer to an
1691        integer error code. When there is a compile-time failure, this is set
1692        non-zero, in addition to the error test pointer being set to point to an
1693        error message. The new argument may be NULL if no error number is required
1694        (but then you may as well call pcre_compile(), which is now just a
1695        wrapper). This facility is provided because some applications need a
1696        numeric error indication, but it has also enabled me to tidy up the way
1697        compile-time errors are handled in the POSIX wrapper.
1699    16. Added VPATH=.libs to the makefile; this should help when building with one
1700        prefix path and installing with another. (Or so I'm told by someone who
1701        knows more about this stuff than I do.)
1703    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1704        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1705        match everything, including newlines. This is not POSIX-compatible, but
1706        somebody wanted the feature. From pcretest it can be activated by using
1707        both the P and the s flags.
1709    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1711    19. libpcre.pc was being incorrectly installed as executable.
1713    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1714        it now also looks for '\r' so that it will work unmodified on Windows.
1716    21. Added Google's contributed C++ wrapper to the distribution.
1718    22. Added some untidy missing memory free() calls in pcretest, to keep
1719        Electric Fence happy when testing.
1723    Version 5.0 13-Sep-04
1724    ---------------------
1726     1. Internal change: literal characters are no longer packed up into items
1727        containing multiple characters in a single byte-string. Each character
1728        is now matched using a separate opcode. However, there may be more than one
1729        byte in the character in UTF-8 mode.
1731     2. The pcre_callout_block structure has two new fields: pattern_position and
1732        next_item_length. These contain the offset in the pattern to the next match
1733        item, and its length, respectively.
1735     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1736        insertion of callouts before each pattern item. Added the /C option to
1737        pcretest to make use of this.
1739     4. On the advice of a Windows user, the lines
1741          #if defined(_WIN32) || defined(WIN32)
1742          _setmode( _fileno( stdout ), 0x8000 );
1743          #endif  /* defined(_WIN32) || defined(WIN32) */
1745        have been added to the source of pcretest. This apparently does useful
1746        magic in relation to line terminators.
1748     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1749        for the benefit of those environments where the "b" makes a difference.
1751     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1752        to know about it. I have put a hack into configure.in that adds in code
1753        to set GCC=yes if CC=icc. This seems to end up at a point in the
1754        generated configure script that is early enough to affect the setting of
1755        compiler options, which is what is needed, but I have no means of testing
1756        whether it really works. (The user who reported this had patched the
1757        generated configure script, which of course I cannot do.)
1759        LATER: After change 22 below (new libtool files), the configure script
1760        seems to know about icc (and also ecc). Therefore, I have commented out
1761        this hack in configure.in.
1763     7. Added support for pkg-config (2 patches were sent in).
1765     8. Negated POSIX character classes that used a combination of internal tables
1766        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1767        [[:^ascii]]. Typically, they would match almost any characters. The other
1768        POSIX classes were not broken in this way.
1770     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1771        to find the match, as PCRE was deluded into thinking that the match had to
1772        start at the start point or following a newline. The same bug applied to
1773        patterns with negative forward assertions or any backward assertions
1774        preceding ".*" at the start, unless the pattern required a fixed first
1775        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1777    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1778        starting at the last subject character, bytes beyond the end of the subject
1779        string were read.
1781    11. Renamed the variable "class" as "classbits" to make life easier for C++
1782        users. (Previously there was a macro definition, but it apparently wasn't
1783        enough.)
1785    12. Added the new field "tables" to the extra data so that tables can be passed
1786        in at exec time, or the internal tables can be re-selected. This allows
1787        a compiled regex to be saved and re-used at a later time by a different
1788        program that might have everything at different addresses.
1790    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1791        -R library as well as a -L library.
1793    14. The debugging options of pcretest (-d on the command line or D on a
1794        pattern) showed incorrect output for anything following an extended class
1795        that contained multibyte characters and which was followed by a quantifier.
1797    15. Added optional support for general category Unicode character properties
1798        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1799        support. It adds about 90K to the size of the library. The meanings of the
1800        inbuilt class escapes such as \d and \s have NOT been changed.
1802    16. Updated pcredemo.c to include calls to free() to release the memory for the
1803        compiled pattern.
1805    17. The generated file chartables.c was being created in the source directory
1806        instead of in the building directory. This caused the build to fail if the
1807        source directory was different from the building directory, and was
1808        read-only.
1810    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1811        file. No doubt somebody will tell me if they don't make sense... Also added
1812        Dan Mooney's comments about building on OpenVMS.
1814    19. Added support for partial matching via the PCRE_PARTIAL option for
1815        pcre_exec() and the \P data escape in pcretest.
1817    20. Extended pcretest with 3 new pattern features:
1819        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1820              write the compiled pattern to the file whose name is "rest-of-line".
1821              This is a straight binary dump of the data, with the saved pointer to
1822              the character tables forced to be NULL. The study data, if any, is
1823              written too. After writing, pcretest reads a new pattern.
1825        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1826              compiled pattern from the given file. There must not be any
1827              occurrences of "<" in the file name (pretty unlikely); if there are,
1828              pcretest will instead treat the initial "<" as a pattern delimiter.
1829              After reading in the pattern, pcretest goes on to read data lines as
1830              usual.
1832        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1833              and 16-bit fields in a compiled pattern, to simulate a pattern that
1834              was compiled on a host of opposite endianness.
1836    21. The pcre-exec() function can now cope with patterns that were compiled on
1837        hosts of opposite endianness, with this restriction:
1839          As for any compiled expression that is saved and used later, the tables
1840          pointer field cannot be preserved; the extra_data field in the arguments
1841          to pcre_exec() should be used to pass in a tables address if a value
1842          other than the default internal tables were used at compile time.
1844    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1845        now diagnosed as an error. Previously, most of the time, a negative number
1846        would have been treated as zero, but if in addition "ovector" was passed as
1847        NULL, a crash could occur.
1849    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1850        new versions from the libtool 1.5 distribution (the last one is a copy of
1851        a file called libtool.m4). This seems to have fixed the need to patch
1852        "configure" to support Darwin 1.3 (which I used to do). However, I still
1853        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1854        workstation).
1856    24. Changed the PCRE licence to be the more standard "BSD" licence.
1859    Version 4.5 01-Dec-03
1860    ---------------------
1862     1. There has been some re-arrangement of the code for the match() function so
1863        that it can be compiled in a version that does not call itself recursively.
1864        Instead, it keeps those local variables that need separate instances for
1865        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1866        needs to "recurse". Keeping track of where control must go is done by means
1867        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1868        hide most of the details from the main code, and operates only if
1869        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1870        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1871        operating.
1873        To make it easier for callers to provide specially tailored get/free
1874        functions for this usage, two new functions, pcre_stack_malloc, and
1875        pcre_stack_free, are used. They are always called in strict stacking order,
1876        and the size of block requested is always the same.
1878        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1879        PCRE has been compiled to use the stack or the heap for recursion. The
1880        -C option of pcretest uses this to show which version is compiled.
1882        A new data escape \S, is added to pcretest; it causes the amounts of store
1883        obtained and freed by both kinds of malloc/free at match time to be added
1884        to the output.
1886     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1887        what's available on my current Linux desktop machine.
1889     3. When matching a UTF-8 string, the test for a valid string at the start has
1890        been extended. If start_offset is not zero, PCRE now checks that it points
1891        to a byte that is the start of a UTF-8 character. If not, it returns
1892        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1893        this is necessary because there may be backward assertions in the pattern.
1894        When matching the same subject several times, it may save resources to use
1895        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1897     4. The code for checking the validity of UTF-8 strings has been tightened so
1898        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1899        containing "overlong sequences".
1901     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1902        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1903        should have been "&", but it just so happened that all the cases this let
1904        through by mistake were picked up later in the function.
1906     6. I had used a variable called "isblank" - this is a C99 function, causing
1907        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1909     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1910        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1911        so the version is shown; (c) stop "make test" echoing "./RunTest".
1913     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1915     9. The prototype for memmove() for systems that don't have it was using
1916        size_t, but the inclusion of the header that defines size_t was later. I've
1917        moved the #includes for the C headers earlier to avoid this.
1919    10. Added some adjustments to the code to make it easier to compiler on certain
1920        special systems:
1922          (a) Some "const" qualifiers were missing.
1923          (b) Added the macro EXPORT before all exported functions; by default this
1924              is defined to be empty.
1925          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1926              that it reads its output file name as an argument instead of writing
1927              to the standard output and assuming this can be redirected.
1929    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1930        class containing characters with values greater than 255, PCRE compilation
1931        went into a loop.
1933    12. A recursive reference to a subpattern that was within another subpattern
1934        that had a minimum quantifier of zero caused PCRE to crash. For example,
1935        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1936        recursion. If the recursively-called subpattern itself had a zero repeat,
1937        that was OK.
1939    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1940        buffer into which it was copied (for escape processing) was still set at
1941        1024, so long lines caused crashes.
1943    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1944        "internal error: code overflow...". This applied to any character class
1945        that was followed by a possessive quantifier.
1947    15. Modified the Makefile to add libpcre.la as a prerequisite for
1948        libpcreposix.la because I was told this is needed for a parallel build to
1949        work.
1951    16. If a pattern that contained .* following optional items at the start was
1952        studied, the wrong optimizing data was generated, leading to matching
1953        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1954        matching string must start with a or b or c. The correct conclusion for
1955        this pattern is that a match can start with any character.
1958    Version 4.4 13-Aug-03
1959    ---------------------
1961     1. In UTF-8 mode, a character class containing characters with values between
1962        127 and 255 was not handled correctly if the compiled pattern was studied.
1963        In fixing this, I have also improved the studying algorithm for such
1964        classes (slightly).
1966     2. Three internal functions had redundant arguments passed to them. Removal
1967        might give a very teeny performance improvement.
1969     3. Documentation bug: the value of the capture_top field in a callout is *one
1970        more than* the number of the hightest numbered captured substring.
1972     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1973        in incorrectly linking with a previously installed version. They now link
1974        explicitly with libpcre.la.
1976     5. configure.in no longer needs to recognize Cygwin specially.
1978     6. A problem in pcre.in for Windows platforms is fixed.
1980     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1981        pcretest, it used to include the size of the study block as part of its
1982        output. Unfortunately, the structure contains a field that has a different
1983        size on different hardware architectures. This meant that the tests that
1984        showed this size failed. As the block is currently always of a fixed size,
1985        this information isn't actually particularly useful in pcretest output, so
1986        I have just removed it.
1988     8. Three pre-processor statements accidentally did not start in column 1.
1989        Sadly, there are *still* compilers around that complain, even though
1990        standard C has not required this for well over a decade. Sigh.
1992     9. In pcretest, the code for checking callouts passed small integers in the
1993        callout_data field, which is a void * field. However, some picky compilers
1994        complained about the casts involved for this on 64-bit systems. Now
1995        pcretest passes the address of the small integer instead, which should get
1996        rid of the warnings.
1998    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1999        both compile and run time, and gives an error if an invalid UTF-8 sequence
2000        is found. There is a option for disabling this check in cases where the
2001        string is known to be correct and/or the maximum performance is wanted.
2003    11. In response to a bug report, I changed one line in Makefile.in from
2005            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2006        to
2007            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2009        to look similar to other lines, but I have no way of telling whether this
2010        is the right thing to do, as I do not use Windows. No doubt I'll get told
2011        if it's wrong...
2014    Version 4.3 21-May-03
2015    ---------------------
2017    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2018       Makefile.
2020    2. Some refactoring to improve the quality of the code:
2022       (i)   The utf8_table... variables are now declared "const".
2024       (ii)  The code for \cx, which used the "case flipping" table to upper case
2025             lower case letters, now just substracts 32. This is ASCII-specific,
2026             but the whole concept of \cx is ASCII-specific, so it seems
2027             reasonable.
2029       (iii) PCRE was using its character types table to recognize decimal and
2030             hexadecimal digits in the pattern. This is silly, because it handles
2031             only 0-9, a-f, and A-F, but the character types table is locale-
2032             specific, which means strange things might happen. A private
2033             table is now used for this - though it costs 256 bytes, a table is
2034             much faster than multiple explicit tests. Of course, the standard
2035             character types table is still used for matching digits in subject
2036             strings against \d.
2038       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2039             ending in _t are). So I've renamed it as ESC_tee.
2041    3. The first argument for regexec() in the POSIX wrapper should have been
2042       defined as "const".
2044    4. Changed pcretest to use malloc() for its buffers so that they can be
2045       Electric Fenced for debugging.
2047    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2048       to read one or more bytes before the start of the subject string. Often this
2049       had no effect on PCRE's behaviour, but in some circumstances it could
2050       provoke a segmentation fault.
2052    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2053       to try to read one or more bytes before the start of the subject string.
2055    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2056       UTF-8 support could misbehave in various ways if the subject string
2057       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2058       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2059       back over UTF-8 characters.)
2062    Version 4.2 14-Apr-03
2063    ---------------------
2065    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2067    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2068         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2069         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2070         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2071         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2072           and BUILD_EXEEXT
2073         Note: automatic setting of the BUILD variables is not yet working
2074         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2075           compile-time but not at link-time
2076         [LINK]: use for linking executables only
2077         make different versions for Windows and non-Windows
2078         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2079           libraries
2080         [LINK_FOR_BUILD]: new variable
2081         [OBJEXT]: use throughout
2082         [EXEEXT]: use throughout
2083         <winshared>: new target
2084         <wininstall>: new target
2085         <dftables.o>: use native compiler
2086         <dftables>: use native linker
2087         <install>: handle Windows platform correctly
2088         <clean>: ditto
2089         <check>: ditto
2090         copy DLL to top builddir before testing
2092       As part of these changes, -no-undefined was removed again. This was reported
2093       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2094       in any case.
2096    3. Some tidies to get rid of compiler warnings:
2098       . In the match_data structure, match_limit was an unsigned long int, whereas
2099         match_call_count was an int. I've made them both unsigned long ints.
2101       . In pcretest the fact that a const uschar * doesn't automatically cast to
2102         a void * provoked a warning.
2104       . Turning on some more compiler warnings threw up some "shadow" variables
2105         and a few more missing casts.
2107    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2108       option, a class that contained a single character with a value between 128
2109       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2111    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2112       option, a class that contained several characters, but with at least one
2113       whose value was between 128 and 255 caused PCRE to crash.
2116    Version 4.1 12-Mar-03
2117    ---------------------
2119    1. Compiling with gcc -pedantic found a couple of places where casts were
2120    needed, and a string in dftables.c that was longer than standard compilers are
2121    required to support.
2123    2. Compiling with Sun's compiler found a few more places where the code could
2124    be tidied up in order to avoid warnings.
2126    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2127    first of these names is deprecated in the latest Autoconf in favour of the name
2128    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2129    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2130    analogy I have changed it to CFLAGS_FOR_BUILD.
2132    4. Added -no-undefined to the linking command in the Makefile, because this is
2133    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2134    linking step for the pcreposix library.
2136    5. PCRE was failing to diagnose the case of two named groups with the same
2137    name.
2139    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2140    literal character that is needed in the subject for a match, and scans along to
2141    ensure that it is present before embarking on the full matching process. This
2142    saves time in cases of nested unlimited repeats that are never going to match.
2143    Problem: the scan can take a lot of time if the subject is very long (e.g.
2144    megabytes), thus penalizing straightforward matches. It is now done only if the
2145    amount of subject to be scanned is less than 1000 bytes.
2147    7. A lesser problem with the same optimization is that it was recording the
2148    first character of an anchored pattern as "needed", thus provoking a search
2149    right along the subject, even when the first match of the pattern was going to
2150    fail. The "needed" character is now not set for anchored patterns, unless it
2151    follows something in the pattern that is of non-fixed length. Thus, it still
2152    fulfils its original purpose of finding quick non-matches in cases of nested
2153    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2156    Version 4.0 17-Feb-03
2157    ---------------------
2159    1. If a comment in an extended regex that started immediately after a meta-item
2160    extended to the end of string, PCRE compiled incorrect data. This could lead to
2161    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2163    2. Moved to autoconf 2.53 and libtool 1.4.2.
2165    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2166    the special perltest8 script is no longer needed - all the tests can be run
2167    from a single perltest script.
2169    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2170    by \s. It has now been removed in PCRE. This means it isn't recognized as
2171    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2172    class [:space:] *does* include VT, thereby creating a mess.
2174    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2175    space and tab.
2177    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2178    its new features into the main test script, reducing the number of scripts.
2180    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2181    were backward compatible, and made the (?i) apply to the whole pattern, as if
2182    /i were given. Now it behaves more logically, and applies the option setting
2183    only to what follows. PCRE has been changed to follow suit. However, if it
2184    finds options settings right at the start of the pattern, it extracts them into
2185    the global options, as before. Thus, they show up in the info data.
2187    8. Added support for the \Q...\E escape sequence. Characters in between are
2188    treated as literals. This is slightly different from Perl in that $ and @ are
2189    also handled as literals inside the quotes. In Perl, they will cause variable
2190    interpolation. Note the following examples:
2192        Pattern            PCRE matches      Perl matches
2194        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2195        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2196        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2198    For compatibility with Perl, \Q...\E sequences are recognized inside character
2199    classes as well as outside them.
2201    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2202    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2203    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2204    signed/unsigned warnings.
2206    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2207    option for pcretest, so I've replaced it by a simple function that does just
2208    that job.
2210    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2211    "pcregrep -".
2213    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2214    Java package. This provides some syntactic sugar for simple cases of what my
2215    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2216    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2217    item, you can use this simplified notation. Note that only makes sense with
2218    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2219    greediness, whatever the setting of the PCRE_UNGREEDY option.
2221    13. A change of greediness default within a pattern was not taking effect at
2222    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2223    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2224    was abstracted outside.
2226    14. PCRE now supports the \G assertion. It is true when the current matching
2227    position is at the start point of the match. This differs from \A when the
2228    starting offset is non-zero. Used with the /g option of pcretest (or similar
2229    code), it works in the same way as it does for Perl's /g option. If all
2230    alternatives of a regex begin with \G, the expression is anchored to the start
2231    match position, and the "anchored" flag is set in the compiled expression.
2233    15. Some bugs concerning the handling of certain option changes within patterns
2234    have been fixed. These applied to options other than (?ims). For example,
2235    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2236    been the other way round. Some of this was related to change 7 above.
2238    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2239    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2240    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2241    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2243    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2244    mode. Unlike ".", it always matches newline, whatever the setting of
2245    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2246    assertions. Perl allows it, but it doesn't (in general) work because it can't
2247    calculate the length of the lookbehind. At least, that's the case for Perl
2248    5.8.0 - I've been told they are going to document that it doesn't work in
2249    future.
2251    18. Added an error diagnosis for escapes that PCRE does not support: these are
2252    \L, \l, \N, \P, \p, \U, \u, and \X.
2254    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2255    reading past the end of the pattern in cases such as /[abcd/.
2257    20. PCRE was getting more memory than necessary for patterns with classes that
2258    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2260    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2261    compiling PCRE for use with Virtual Pascal.
2263    22. Small fix to the Makefile to make it work properly if the build is done
2264    outside the source tree.
2266    23. Added a new extension: a condition to go with recursion. If a conditional
2267    subpattern starts with (?(R) the "true" branch is used if recursion has
2268    happened, whereas the "false" branch is used only at the top level.
2270    24. When there was a very long string of literal characters (over 255 bytes
2271    without UTF support, over 250 bytes with UTF support), the computation of how
2272    much memory was required could be incorrect, leading to segfaults or other
2273    strange effects.
2275    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2276    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2277    there was a subsequent back reference to those brackets. This meant that, for
2278    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2279    possible to check for precisely this case. All we can do is abandon the
2280    optimization if .* occurs inside capturing brackets when there are any back
2281    references whatsoever. (See below for a better fix that came later.)
2283    26. The handling of the optimization for finding the first character of a
2284    non-anchored pattern, and for finding a character that is required later in the
2285    match were failing in some cases. This didn't break the matching; it just
2286    failed to optimize when it could. The way this is done has been re-implemented.
2288    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2290    28. Added a new feature that provides some of the functionality that Perl
2291    provides with (?{...}). The facility is termed a "callout". The way it is done
2292    in PCRE is for the caller to provide an optional function, by setting
2293    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2294    global variable. By default it is unset, which disables all calling out. To get
2295    the function called, the regex must include (?C) at appropriate points. This
2296    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2297    This provides a means of identifying different callout points. When PCRE
2298    reaches such a point in the regex, if pcre_callout has been set, the external
2299    function is called. It is provided with data in a structure called
2300    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2301    matching continues; if it returns a non-zero value, the match at the current
2302    point fails. However, backtracking will occur if possible. [This was changed
2303    later and other features added - see item 49 below.]
2305    29. pcretest is upgraded to test the callout functionality. It provides a
2306    callout function that displays information. By default, it shows the start of
2307    the match and the current position in the text. There are some new data escapes
2308    to vary what happens:
2310        \C+         in addition, show current contents of captured substrings
2311        \C-         do not supply a callout function
2312        \C!n        return 1 when callout number n is reached
2313        \C!n!m      return 1 when callout number n is reached for the mth time
2315    30. If pcregrep was called with the -l option and just a single file name, it
2316    output "<stdin>" if a match was found, instead of the file name.
2318    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2319    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2320    pcre_exec(). This saves a malloc/free per call. The default value of
2321    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2322    when configuring.
2324    32. The default maximum size of a compiled pattern is 64K. There have been a
2325    few cases of people hitting this limit. The code now uses macros to handle the
2326    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2327    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2328    configuring. Tests 2 and 5 work only with 2-byte links because they output
2329    debugging information about compiled patterns.
2331    33. Internal code re-arrangements:
2333    (a) Moved the debugging function for printing out a compiled regex into
2334        its own source file (printint.c) and used #include to pull it into
2335        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2336        separate copies.
2338    (b) Defined the list of op-code names for debugging as a macro in
2339        internal.h so that it is next to the definition of the opcodes.
2341    (c) Defined a table of op-code lengths for simpler skipping along compiled
2342        code. This is again a macro in internal.h so that it is next to the
2343        definition of the opcodes.
2345    34. Added support for recursive calls to individual subpatterns, along the
2346    lines of Robin Houston's patch (but implemented somewhat differently).
2348    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2349    allow it to read and process whole directories in Win32. This code was
2350    contributed by Lionel Fourquaux; it has not been tested by me.
2352    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2353    used to name a group. Names consist of alphanumerics and underscores, and must
2354    be unique. Back references use the syntax (?P=name) and recursive calls use
2355    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2356    numbers. The function pcre_fullinfo() can be used after compilation to extract
2357    a name/number map. There are three relevant calls:
2359      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2360      PCRE_INFO_NAMECOUNT            yields the number of entries
2361      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2363    The map is a vector of fixed-size entries. The size of each entry depends on
2364    the length of the longest name used. The first two bytes of each entry are the
2365    group number, most significant byte first. There follows the corresponding
2366    name, zero terminated. The names are in alphabetical order.
2368    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2369    case instead of 255. Making it the same both with and without UTF-8 support
2370    means that the same test output works with both.
2372    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2373    calling malloc() with a zero argument.
2375    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2376    optimization. I've improved things by keeping a bitmap of backreferences with
2377    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2378    fact referenced, the optimization can be applied. It is unlikely that a
2379    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2380    the match to follow \n) will appear inside brackets with a number greater than
2381    31, but if it does, any back reference > 31 suppresses the optimization.
2383    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2384    of disabling numbered capturing parentheses. Any opening parenthesis that is
2385    not followed by ? behaves as if it were followed by ?: but named parentheses
2386    can still be used for capturing (and they will acquire numbers in the usual
2387    way).
2389    41. Redesigned the return codes from the match() function into yes/no/error so
2390    that errors can be passed back from deep inside the nested calls. A malloc
2391    failure while inside a recursive subpattern call now causes the
2392    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2394    42. It is now possible to set a limit on the number of times the match()
2395    function is called in a call to pcre_exec(). This facility makes it possible to
2396    limit the amount of recursion and backtracking, though not in a directly
2397    obvious way, because the match() function is used in a number of different
2398    circumstances. The count starts from zero for each position in the subject
2399    string (for non-anchored patterns). The default limit is, for compatibility, a
2400    large number, namely 10 000 000. You can change this in two ways:
2402    (a) When configuring PCRE before making, you can use --with-match-limit=n
2403        to set a default value for the compiled library.
2405    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2406        a different value is set. See 45 below.
2408    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2410    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2411    of things that can be changed at compile time. The first argument specifies
2412    what is wanted and the second points to where the information is to be placed.
2413    The current list of available information is:
2415      PCRE_CONFIG_UTF8
2417    The output is an integer that is set to one if UTF-8 support is available;
2418    otherwise it is set to zero.
2422    The output is an integer that it set to the value of the code that is used for
2423    newline. It is either LF (10) or CR (13).
2427    The output is an integer that contains the number of bytes used for internal
2428    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2432    The output is an integer that contains the threshold above which the POSIX
2433    interface uses malloc() for output vectors. See item 31 above.
2437    The output is an unsigned integer that contains the default limit of the number
2438    of match() calls in a pcre_exec() execution. See 42 above.
2440    44. pcretest has been upgraded by the addition of the -C option. This causes it
2441    to extract all the available output from the new pcre_config() function, and to
2442    output it. The program then exits immediately.
2444    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2445    order to support additional features. One way would have been to define
2446    pcre_exec2() (for example) with extra arguments, but this would not have been
2447    extensible, and would also have required all calls to the original function to
2448    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2449    is used for passing in "extra" data from pcre_study().
2451    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2452    contains the following fields:
2454      flags         a bitmap indicating which of the following fields are set
2455      study_data    opaque data from pcre_study()
2456      match_limit   a way of specifying a limit on match() calls for a specific
2457                      call to pcre_exec()
2458      callout_data  data for callouts (see 49 below)
2460    The flag bits are also defined in pcre.h, and are
2466    The pcre_study() function now returns one of these new pcre_extra blocks, with
2467    the actual study data pointed to by the study_data field, and the
2468    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2469    before. That is, this change is entirely upwards-compatible and requires no
2470    change to existing code.
2472    If you want to pass in additional data to pcre_exec(), you can either place it
2473    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2474    block.
2476    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2477    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2478    times with different match limits, until it finds the minimum value needed for
2479    pcre_exec() to complete. The value is then output. This can be instructive; for
2480    most simple matches the number is quite small, but for pathological cases it
2481    gets very large very quickly.
2483    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2484    returns the size of the data block pointed to by the study_data field in a
2485    pcre_extra block, that is, the value that was passed as the argument to
2486    pcre_malloc() when PCRE was getting memory in which to place the information
2487    created by pcre_study(). The fourth argument should point to a size_t variable.
2488    pcretest has been extended so that this information is shown after a successful
2489    pcre_study() call when information about the compiled regex is being displayed.
2491    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2492    because what follows is always an absolute path. (Later: it turns out that this
2493    is more than cosmetic for MinGW, because it doesn't like empty path
2494    components.)
2496    49. Some changes have been made to the callout feature (see 28 above):
2498    (i)  A callout function now has three choices for what it returns:
2500           0  =>  success, carry on matching
2501         > 0  =>  failure at this point, but backtrack if possible
2502         < 0  =>  serious error, return this value from pcre_exec()
2504         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2505         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2506         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2507         use by callout functions. It will never be used by PCRE itself.
2509    (ii) The pcre_extra structure (see 45 above) has a void * field called
2510         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2511         pcre_callout_block structure has a field of the same name. The contents of
2512         the field passed in the pcre_extra structure are passed to the callout
2513         function in the corresponding field in the callout block. This makes it
2514         easier to use the same callout-containing regex from multiple threads. For
2515         testing, the pcretest program has a new data escape
2517           \C*n        pass the number n (may be negative) as callout_data
2519         If the callout function in pcretest receives a non-zero value as
2520         callout_data, it returns that value.
2522    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2523    there were some redundant $(CFLAGS) in commands that are now specified as
2524    $(LINK), which already includes $(CFLAGS).
2526    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2527    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2528    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2529    one-byte characters throughout. Note that case-insensitive matching applies
2530    only to characters whose values are less than 256. PCRE doesn't support the
2531    notion of cases for higher-valued characters.
2533    (i)   A character class whose characters are all within 0-255 is handled as
2534          a bit map, and the map is inverted for negative classes. Previously, a
2535          character > 255 always failed to match such a class; however it should
2536          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2538    (ii)  A negated character class with a single character < 255 is coded as
2539          "not this character" (OP_NOT). This wasn't working properly when the test
2540          character was multibyte, either singly or repeated.
2542    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2543          mode, for example: \x{100}{2,3}.
2545    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2546          singly or repeated) now correctly test multibyte characters. However,
2547          PCRE doesn't recognize any characters with values greater than 255 as
2548          digits, spaces, or word characters. Such characters always match \D, \S,
2549          and \W, and never match \d, \s, or \w.
2551    (v)   Classes may now contain characters and character ranges with values
2552          greater than 255. For example: [ab\x{100}-\x{400}].
2554    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2555          PCRE in UTF-8 mode.
2557    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2558    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2559    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2560    value.)
2562    53. The single man page has become too large. I have therefore split it up into
2563    a number of separate man pages. These also give rise to individual HTML pages;
2564    these are now put in a separate directory, and there is an index.html page that
2565    lists them all. Some hyperlinking between the pages has been installed.
2567    54. Added convenience functions for handling named capturing parentheses.
2569    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2570    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2571    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2572    are faulted.
2574    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2575    calling configure. These values are used when compiling the dftables.c program
2576    which is run to generate the source of the default character tables. They
2577    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2578    you will need to set these values.
2580    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2583    Version 3.9 02-Jan-02
2584    ---------------------
2586    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2588    2. If --disable-static was given, the building process failed when trying to
2589    build pcretest and pcregrep. (For some reason it was using libtool to compile
2590    them, which is not right, as they aren't part of the library.)
2593    Version 3.8 18-Dec-01
2594    ---------------------
2596    1. The experimental UTF-8 code was completely screwed up. It was packing the
2597    bytes in the wrong order. How dumb can you get?
2600    Version 3.7 29-Oct-01
2601    ---------------------
2603    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2604    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2605    this didn't happen under Solaris 8, where I normally test things.
2607    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2608    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2609    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2610    this fix an hour or so after the initial 3.7 release.)
2613    Version 3.6 23-Oct-01
2614    ---------------------
2616    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2617    offsets passed as NULL with zero offset count.
2619    2. The config.guess and config.sub files had not been updated when I moved to
2620    the latest autoconf.
2623    Version 3.5 15-Aug-01
2624    ---------------------
2626    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2627    had been forgotten.
2629    2. By using declared but undefined structures, we can avoid using "void"
2630    definitions in pcre.h while keeping the internal definitions of the structures
2631    private.
2633    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2634    user point of view, this means that both static and shared libraries are built
2635    by default, but this can be individually controlled. More of the work of
2636    handling this static/shared cases is now inside libtool instead of PCRE's make
2637    file.
2639    4. The pcretest utility is now installed along with pcregrep because it is
2640    useful for users (to test regexs) and by doing this, it automatically gets
2641    relinked by libtool. The documentation has been turned into a man page, so
2642    there are now .1, .txt, and .html versions in /doc.
2644    5. Upgrades to pcregrep:
2645       (i)   Added long-form option names like gnu grep.
2646       (ii)  Added --help to list all options with an explanatory phrase.
2647       (iii) Added -r, --recursive to recurse into sub-directories.
2648       (iv)  Added -f, --file to read patterns from a file.
2650    6. pcre_exec() was referring to its "code" argument before testing that
2651    argument for NULL (and giving an error if it was NULL).
2653    7. Upgraded Makefile.in to allow for compiling in a different directory from
2654    the source directory.
2656    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2657    options bits, the pointer it was passed was to an int instead of to an unsigned
2658    long int. This mattered only on 64-bit systems.
2660    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2661    generated) instead of pcre.in, which it its source. Also made the same change
2662    in several of the .c files.
2664    10. A new release of gcc defines printf() as a macro, which broke pcretest
2665    because it had an ifdef in the middle of a string argument for printf(). Fixed
2666    by using separate calls to printf().
2668    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2669    script, to force use of CR or LF instead of \n in the source. On non-Unix
2670    systems, the value can be set in config.h.
2672    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2673    absolute limit. Changed the text of the error message to make this clear, and
2674    likewise updated the man page.
2676    13. The limit of 99 on the number of capturing subpatterns has been removed.
2677    The new limit is 65535, which I hope will not be a "real" limit.
2680  Version 3.4 22-Aug-00  Version 3.4 22-Aug-00
2681  ---------------------  ---------------------

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