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revision 61 by nigel, Sat Feb 24 21:39:58 2007 UTC revision 355 by ph10, Mon Jul 7 17:45:23 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 3.0 02-Jan-02  Version 8.0 02 Jul-08
5    ---------------------
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
17    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18        a group with a zero qualifier. The result of the study could be incorrect,
19        or the function might crash, depending on the pattern.
21    4.  Caseless matching was not working for non-ASCII characters in back
22        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23        It now works when Unicode Property Support is available.
25    5.  In pcretest, an escape such as \x{de} in the data was always generating
26        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
27        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
28        truncation.
31    Version 7.7 07-May-08
32    ---------------------
34    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
35        a string to a long long, pretend we don't even have a long long." This is
36        done by checking for the strtoq, strtoll, and _strtoi64 functions.
38    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
39        pre-7.6 versions, which defined a global no_arg variable instead of putting
40        it in the RE class. (See also #8 below.)
42    3.  Remove a line of dead code, identified by coverity and reported by Nuno
43        Lopes.
45    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
47        (1) The include/exclude patterns were being applied to the whole pathnames
48            of files, instead of just to the final components.
50        (2) If there was more than one level of directory, the subdirectories were
51            skipped unless they satisfied the include/exclude conditions. This is
52            inconsistent with GNU grep (and could even be seen as contrary to the
53            pcregrep specification - which I improved to make it absolutely clear).
54            The action now is always to scan all levels of directory, and just
55            apply the include/exclude patterns to regular files.
57    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
58        --exclude_dir in the tests to avoid scanning .svn directories.
60    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
61        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
62        doesn't support NULs in patterns.
64    7.  Added some missing "const"s to declarations of static tables in
65        pcre_compile.c and pcre_dfa_exec.c.
67    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
68        caused by fix #2  above. (Subsequently also a second patch to fix the
69        first patch. And a third patch - this was a messy problem.)
71    9.  Applied Craig's patch to remove the use of push_back().
73    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
74        matching function regexec().
76    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
77        which, however, unlike Perl's \g{...}, are subroutine calls, not back
78        references. PCRE supports relative numbers with this syntax (I don't think
79        Oniguruma does).
81    12. Previously, a group with a zero repeat such as (...){0} was completely
82        omitted from the compiled regex. However, this means that if the group
83        was called as a subroutine from elsewhere in the pattern, things went wrong
84        (an internal error was given). Such groups are now left in the compiled
85        pattern, with a new opcode that causes them to be skipped at execution
86        time.
88    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
89        to the way PCRE behaves:
91        (a) A lone ] character is dis-allowed (Perl treats it as data).
93        (b) A back reference to an unmatched subpattern matches an empty string
94            (Perl fails the current match path).
96        (c) A data ] in a character class must be notated as \] because if the
97            first data character in a class is ], it defines an empty class. (In
98            Perl it is not possible to have an empty class.) The empty class []
99            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
100            The negative empty class [^] matches any one character, independently
101            of the DOTALL setting.
103    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
104        non-existent subpattern following a character class starting with ']' and
105        containing () gave an internal compiling error instead of "reference to
106        non-existent subpattern". Fortunately, when the pattern did exist, the
107        compiled code was correct. (When scanning forwards to check for the
108        existencd of the subpattern, it was treating the data ']' as terminating
109        the class, so got the count wrong. When actually compiling, the reference
110        was subsequently set up correctly.)
112    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
113        it was being rejected as not supported by pcre_dfa_exec(), even though
114        other assertions are supported. I have made pcre_dfa_exec() support
115        (*FAIL).
117    16. The implementation of 13c above involved the invention of a new opcode,
118        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
119        cannot be changed at match time, I realized I could make a small
120        improvement to matching performance by compiling OP_ALLANY instead of
121        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
122        on the OP_ANY path.
124    17. Compiling pcretest on Windows with readline support failed without the
125        following two fixes: (1) Make the unistd.h include conditional on
126        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
128    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
129        ncurses library to be included for pcretest when ReadLine support is
130        requested, but also to allow for it to be overridden. This patch came from
131        Daniel Bergström.
133    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
134        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
135        any errors with the current Unicode tables. Thanks to Peter Kankowski for
136        spotting this.
139    Version 7.6 28-Jan-08
140    ---------------------
142    1.  A character class containing a very large number of characters with
143        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
144        overflow.
146    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
147        HAVE_LONG_LONG is not defined.
149    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
150        bring them up to date and include new features. This patch includes:
152        - Fixed PH's badly added libz and libbz2 support.
153        - Fixed a problem with static linking.
154        - Added pcredemo. [But later removed - see 7 below.]
155        - Fixed dftables problem and added an option.
156        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
157            HAVE_LONG_LONG.
158        - Added readline support for pcretest.
159        - Added an listing of the option settings after cmake has run.
161    4.  A user submitted a patch to Makefile that makes it easy to create
162        "pcre.dll" under mingw when using Configure/Make. I added stuff to
163        Makefile.am that cause it to include this special target, without
164        affecting anything else. Note that the same mingw target plus all
165        the other distribution libraries and programs are now supported
166        when configuring with CMake (see 6 below) instead of with
167        Configure/Make.
169    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
170        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
171        exported in the Windows port". It has not yet been confirmed that the patch
172        solves the problem, but it does no harm.
174    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
175        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
176        with CMake, and also correct the comment about stack recursion.
178    7.  Remove the automatic building of pcredemo from the ./configure system and
179        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
180        of a program that users should build themselves after PCRE is installed, so
181        building it automatically is not really right. What is more, it gave
182        trouble in some build environments.
184    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
187    Version 7.5 10-Jan-08
188    ---------------------
190    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
191        values in parens when parsing an RE using the C++ wrapper."
193    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
194        Characters greater than 255 were excluded from the class instead of being
195        included.
197    3.  The same bug as (2) above applied to negated POSIX classes such as
198        [:^space:].
200    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
201        defined or documented. It seems to have been a typo for PCRE_STATIC, so
202        I have changed it.
204    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
205        first named subpattern) and a construct such as (?&a) would reference the
206        first named subpattern whose name started with "a" (in other words, the
207        length check was missing). Both these problems are fixed. "Subpattern name
208        expected" is now given for (?&) (a zero-length name), and this patch also
209        makes it give the same error for \k'' (previously it complained that that
210        was a reference to a non-existent subpattern).
212    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
213        this is right because (?- can be followed by option settings as well as by
214        digits. I have, however, made the messages clearer.
216    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
217        than the number used in the conditional) now cause a compile-time error.
218        This is actually not compatible with Perl, which accepts such patterns, but
219        treats the conditional as always being FALSE (as PCRE used to), but it
220        seems to me that giving a diagnostic is better.
222    8.  Change "alphameric" to the more common word "alphanumeric" in comments
223        and messages.
225    9.  Fix two occurrences of "backslash" in comments that should have been
226        "backspace".
228    10. Remove two redundant lines of code that can never be obeyed (their function
229        was moved elsewhere).
231    11. The program that makes PCRE's Unicode character property table had a bug
232        which caused it to generate incorrect table entries for sequences of
233        characters that have the same character type, but are in different scripts.
234        It amalgamated them into a single range, with the script of the first of
235        them. In other words, some characters were in the wrong script. There were
236        thirteen such cases, affecting characters in the following ranges:
238          U+002b0 - U+002c1
239          U+0060c - U+0060d
240          U+0061e - U+00612
241          U+0064b - U+0065e
242          U+0074d - U+0076d
243          U+01800 - U+01805
244          U+01d00 - U+01d77
245          U+01d9b - U+01dbf
246          U+0200b - U+0200f
247          U+030fc - U+030fe
248          U+03260 - U+0327f
249          U+0fb46 - U+0fbb1
250          U+10450 - U+1049d
252    12. The -o option (show only the matching part of a line) for pcregrep was not
253        compatible with GNU grep in that, if there was more than one match in a
254        line, it showed only the first of them. It now behaves in the same way as
255        GNU grep.
257    13. If the -o and -v options were combined for pcregrep, it printed a blank
258        line for every non-matching line. GNU grep prints nothing, and pcregrep now
259        does the same. The return code can be used to tell if there were any
260        non-matching lines.
262    14. Added --file-offsets and --line-offsets to pcregrep.
264    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
265        infinitely looping recursion. The bug was that positive lookaheads were not
266        being skipped when checking for a possible empty match (negative lookaheads
267        and both kinds of lookbehind were skipped).
269    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
270        inclusion of <windows.h> to before rather than after the definition of
271        INVALID_FILE_ATTRIBUTES (patch from David Byron).
273    17. Specifying a possessive quantifier with a specific limit for a Unicode
274        character property caused pcre_compile() to compile bad code, which led at
275        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
276        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
277        caused the error; without that there was no problem.
279    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
281    19. Added --enable-pcretest-libreadline.
283    20. In pcrecpp.cc, the variable 'count' was incremented twice in
284        RE::GlobalReplace(). As a result, the number of replacements returned was
285        double what it should be. I removed one of the increments, but Craig sent a
286        later patch that removed the other one (the right fix) and added unit tests
287        that check the return values (which was not done before).
289    21. Several CMake things:
291        (1) Arranged that, when cmake is used on Unix, the libraries end up with
292            the names libpcre and libpcreposix, not just pcre and pcreposix.
294        (2) The above change means that pcretest and pcregrep are now correctly
295            linked with the newly-built libraries, not previously installed ones.
299    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
300        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
301        UTF-8 newline character). The key issue is that the pattern starts .*;
302        this means that the match must be either at the beginning, or after a
303        newline. The bug was in the code for advancing after a failed match and
304        checking that the new position followed a newline. It was not taking
305        account of UTF-8 characters correctly.
307    23. PCRE was behaving differently from Perl in the way it recognized POSIX
308        character classes. PCRE was not treating the sequence [:...:] as a
309        character class unless the ... were all letters. Perl, however, seems to
310        allow any characters between [: and :], though of course it rejects as
311        unknown any "names" that contain non-letters, because all the known class
312        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
313        for example, whereas PCRE did not - it did not recognize a POSIX character
314        class. This seemed a bit dangerous, so the code has been changed to be
315        closer to Perl. The behaviour is not identical to Perl, because PCRE will
316        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
317        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
318        Perl does, and where it didn't before.
320    24. Rewrite so as to remove the single use of %n from pcregrep because in some
321        Windows environments %n is disabled by default.
324    Version 7.4 21-Sep-07
325    ---------------------
327    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
328        means that a class such as [\s] counted as "explicit reference to CR or
329        LF". That isn't really right - the whole point of the change was to try to
330        help when there was an actual mention of one of the two characters. So now
331        the change happens only if \r or \n (or a literal CR or LF) character is
332        encountered.
334    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
335        of both had grown to the point where there were only 3 bits left.
336        Fortunately, there was spare space in the data structure, and so I have
337        moved the internal flags into a new 16-bit field to free up more option
338        bits.
340    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
341        but did not set the internal JCHANGED flag - either of these is enough to
342        control the way the "get" function works - but the PCRE_INFO_JCHANGED
343        facility is supposed to tell if (?J) was ever used, so now (?J) at the
344        start sets both bits.
346    4.  Added options (at build time, compile time, exec time) to change \R from
347        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
349    5.  doc/pcresyntax.html was missing from the distribution.
351    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
352        compatibility, even though it is no longer used.
354    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
355        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
356        windows.h file is present (where different names are used). [This was
357        reversed later after testing - see 16 below.]
359    8.  Changed all #include <config.h> to #include "config.h". There were also
360        some further <pcre.h> cases that I changed to "pcre.h".
362    9.  When pcregrep was used with the --colour option, it missed the line ending
363        sequence off the lines that it output.
365    10. It was pointed out to me that arrays of string pointers cause lots of
366        relocations when a shared library is dynamically loaded. A technique of
367        using a single long string with a table of offsets can drastically reduce
368        these. I have refactored PCRE in four places to do this. The result is
369        dramatic:
371          Originally:                          290
372          After changing UCP table:            187
373          After changing error message table:   43
374          After changing table of "verbs"       36
375          After changing table of Posix names   22
377        Thanks to the folks working on Gregex for glib for this insight.
379    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
380        unicode-properties was also set.
382    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
384    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
385        checked only for CRLF.
387    14. Added casts to pcretest.c to avoid compiler warnings.
389    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
391    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
392        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
393        entirely. This removes changes made in 7 above.
395    17. The CMake files have been updated, and there is now more information about
396        building with CMake in the NON-UNIX-USE document.
399    Version 7.3 28-Aug-07
400    ---------------------
402     1. In the rejigging of the build system that eventually resulted in 7.1, the
403        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
404        brackets there is not right, since it causes compilers to look for an
405        installed pcre.h, not the version that is in the source that is being
406        compiled (which of course may be different). I have changed it back to:
408          #include "pcre.h"
410        I have a vague recollection that the change was concerned with compiling in
411        different directories, but in the new build system, that is taken care of
412        by the VPATH setting the Makefile.
414     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
415        when the subject happened to end in the byte 0x85 (e.g. if the last
416        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
417        characters but of course it shouldn't be taken as a newline when it is part
418        of another character. The bug was that, for an unlimited repeat of . in
419        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
420        characters when looking for a newline.
422     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
424     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
425        in debug output.
427     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
428        long printing in the pcrecpp unittest when running under MinGW.
430     6. ESC_K was left out of the EBCDIC table.
432     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
433        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
434        limit also applies to "virtual nesting" when a pattern is recursive, and in
435        this case 1000 isn't so big. I have been able to remove this limit at the
436        expense of backing off one optimization in certain circumstances. Normally,
437        when pcre_exec() would call its internal match() function recursively and
438        immediately return the result unconditionally, it uses a "tail recursion"
439        feature to save stack. However, when a subpattern that can match an empty
440        string has an unlimited repetition quantifier, it no longer makes this
441        optimization. That gives it a stack frame in which to save the data for
442        checking that an empty string has been matched. Previously this was taken
443        from the 1000-entry workspace that had been reserved. So now there is no
444        explicit limit, but more stack is used.
446     8. Applied Daniel's patches to solve problems with the import/export magic
447        syntax that is required for Windows, and which was going wrong for the
448        pcreposix and pcrecpp parts of the library. These were overlooked when this
449        problem was solved for the main library.
451     9. There were some crude static tests to avoid integer overflow when computing
452        the size of patterns that contain repeated groups with explicit upper
453        limits. As the maximum quantifier is 65535, the maximum group length was
454        set at 30,000 so that the product of these two numbers did not overflow a
455        32-bit integer. However, it turns out that people want to use groups that
456        are longer than 30,000 bytes (though not repeat them that many times).
457        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
458        made it possible to implement the integer overflow checks in a much more
459        dynamic way, which I have now done. The artificial limitation on group
460        length has been removed - we now have only the limit on the total length of
461        the compiled pattern, which depends on the LINK_SIZE setting.
463    10. Fixed a bug in the documentation for get/copy named substring when
464        duplicate names are permitted. If none of the named substrings are set, the
465        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
466        empty string.
468    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
469        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
470        because the ] is interpreted as the first data character and the
471        terminating ] is not found. PCRE has been made compatible with Perl in this
472        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
473        cause memory overwriting.
475    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
476        string has been matched (to stop an infinite loop). It was not recognizing
477        a conditional subpattern that could match an empty string if that
478        subpattern was within another subpattern. For example, it looped when
479        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
480        condition was not nested. This bug has been fixed.
482    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
483        past the start of the subject in the presence of bytes with the top bit
484        set, for example "\x8aBCD".
486    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
487        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
489    14. Optimized (?!) to (*FAIL).
491    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
492        This restricts code points to be within the range 0 to 0x10FFFF, excluding
493        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
494        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
495        does: it's just the validity check that is more restrictive.
497    16. Inserted checks for integer overflows during escape sequence (backslash)
498        processing, and also fixed erroneous offset values for syntax errors during
499        backslash processing.
501    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
502        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
504    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
505        caused an overrun.
507    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
508        something other than just ASCII characters) inside a group that had an
509        unlimited repeat caused a loop at compile time (while checking to see
510        whether the group could match an empty string).
512    20. Debugging a pattern containing \p or \P could cause a crash. For example,
513        [\P{Any}] did so. (Error in the code for printing property names.)
515    21. An orphan \E inside a character class could cause a crash.
517    22. A repeated capturing bracket such as (A)? could cause a wild memory
518        reference during compilation.
520    23. There are several functions in pcre_compile() that scan along a compiled
521        expression for various reasons (e.g. to see if it's fixed length for look
522        behind). There were bugs in these functions when a repeated \p or \P was
523        present in the pattern. These operators have additional parameters compared
524        with \d, etc, and these were not being taken into account when moving along
525        the compiled data. Specifically:
527        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
528            length.
530        (b) An item such as \pL+ within a repeated group could cause crashes or
531            loops.
533        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
534            "reference to non-existent subpattern" error.
536        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
538    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
539        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
541    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
543    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
544        character were causing crashes (broken optimization).
546    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
547        \p or \P) caused a compile-time loop.
549    28. More problems have arisen in unanchored patterns when CRLF is a valid line
550        break. For example, the unstudied pattern [\r\n]A does not match the string
551        "\r\nA" because change 7.0/46 below moves the current point on by two
552        characters after failing to match at the start. However, the pattern \nA
553        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
554        the same is true. There doesn't seem any very clean way out of this, but
555        what I have chosen to do makes the common cases work: PCRE now takes note
556        of whether there can be an explicit match for \r or \n anywhere in the
557        pattern, and if so, 7.0/46 no longer applies. As part of this change,
558        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
559        pattern has explicit CR or LF references.
561    29. Added (*CR) etc for changing newline setting at start of pattern.
564    Version 7.2 19-Jun-07
565    ---------------------
567     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
568        which is apparently normally available under Windows.
570     2. Re-jig the pcregrep tests with different newline settings in an attempt
571        to make them independent of the local environment's newline setting.
573     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
575     4. Some of the "internals" tests were previously cut out when the link size
576        was not 2, because the output contained actual offsets. The recent new
577        "Z" feature of pcretest means that these can be cut out, making the tests
578        usable with all link sizes.
580     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
581        stack recursion. This gives a massive performance boost under BSD, but just
582        a small improvement under Linux. However, it saves one field in the frame
583        in all cases.
585     6. Added more features from the forthcoming Perl 5.10:
587        (a) (?-n) (where n is a string of digits) is a relative subroutine or
588            recursion call. It refers to the nth most recently opened parentheses.
590        (b) (?+n) is also a relative subroutine call; it refers to the nth next
591            to be opened parentheses.
593        (c) Conditions that refer to capturing parentheses can be specified
594            relatively, for example, (?(-2)... or (?(+3)...
596        (d) \K resets the start of the current match so that everything before
597            is not part of it.
599        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
601        (f) \g{name} is another synonym - part of Perl 5.10's unification of
602            reference syntax.
604        (g) (?| introduces a group in which the numbering of parentheses in each
605            alternative starts with the same number.
607        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
609     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
612     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
613        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
614        for detecting groups that can match an empty string.
616     9. A pattern with a very large number of alternatives (more than several
617        hundred) was running out of internal workspace during the pre-compile
618        phase, where pcre_compile() figures out how much memory will be needed. A
619        bit of new cunning has reduced the workspace needed for groups with
620        alternatives. The 1000-alternative test pattern now uses 12 bytes of
621        workspace instead of running out of the 4096 that are available.
623    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
625    11. Applied patch from Google to remove an optimization that didn't quite work.
626        The report of the bug said:
628          pcrecpp::RE("a*").FullMatch("aaa") matches, while
629          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
630          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
632    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
633        it matched the wrong number of bytes.
636    Version 7.1 24-Apr-07
637    ---------------------
639     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
640        that is more "standard", making use of automake and other Autotools. There
641        is some re-arrangement of the files and adjustment of comments consequent
642        on this.
644     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
645        for recursive directory scanning broke on some systems because the files
646        are not scanned in any specific order and on different systems the order
647        was different. A call to "sort" has been inserted into RunGrepTest for the
648        approprate test as a short-term fix. In the longer term there may be an
649        alternative.
651     3. I had an email from Eric Raymond about problems translating some of PCRE's
652        man pages to HTML (despite the fact that I distribute HTML pages, some
653        people do their own conversions for various reasons). The problems
654        concerned the use of low-level troff macros .br and .in. I have therefore
655        removed all such uses from the man pages (some were redundant, some could
656        be replaced by .nf/.fi pairs). The 132html script that I use to generate
657        HTML has been updated to handle .nf/.fi and to complain if it encounters
658        .br or .in.
660     4. Updated comments in configure.ac that get placed in config.h.in and also
661        arranged for config.h to be included in the distribution, with the name
662        config.h.generic, for the benefit of those who have to compile without
663        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
665     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
666        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
667        makevp.bat for the current PCRE, using the additional files
668        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
670     6. A Windows user reported a minor discrepancy with test 2, which turned out
671        to be caused by a trailing space on an input line that had got lost in his
672        copy. The trailing space was an accident, so I've just removed it.
674     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
675        that is needed.
677     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
678        as "const" (a) because they are and (b) because it helps the PHP
679        maintainers who have recently made a script to detect big data structures
680        in the php code that should be moved to the .rodata section. I remembered
681        to update Builducptable as well, so it won't revert if ucptable.h is ever
682        re-created.
684     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
685        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
686        order to be able to cut out the UTF-8 tables in the latter when UTF-8
687        support is not required. This saves 1.5-2K of code, which is important in
688        some applications.
690        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
691        so as not to refer to the tables, even though these functions will never be
692        called when UTF-8 support is disabled. Otherwise there are problems with a
693        shared library.
695    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
697        (a) It was defining its arguments as char * instead of void *.
699        (b) It was assuming that all moves were upwards in memory; this was true
700            a long time ago when I wrote it, but is no longer the case.
702        The emulated memove() is provided for those environments that have neither
703        memmove() nor bcopy(). I didn't think anyone used it these days, but that
704        is clearly not the case, as these two bugs were recently reported.
706    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
707        and Detrail to create the HTML documentation, the .txt form of the man
708        pages, and it removes trailing spaces from listed files. It also creates
709        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
710        case, it wraps all the #defines with #ifndefs. This script should be run
711        before "make dist".
713    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
714        with Unicode property support.
716        (a) For a maximizing quantifier, if the two different cases of the
717            character were of different lengths in their UTF-8 codings (there are
718            some cases like this - I found 11), and the matching function had to
719            back up over a mixture of the two cases, it incorrectly assumed they
720            were both the same length.
722        (b) When PCRE was configured to use the heap rather than the stack for
723            recursion during matching, it was not correctly preserving the data for
724            the other case of a UTF-8 character when checking ahead for a match
725            while processing a minimizing repeat. If the check also involved
726            matching a wide character, but failed, corruption could cause an
727            erroneous result when trying to check for a repeat of the original
728            character.
730    13. Some tidying changes to the testing mechanism:
732        (a) The RunTest script now detects the internal link size and whether there
733            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
734            values substituted by "configure". (The RunGrepTest script already did
735            this for UTF-8.) The configure.ac script no longer substitutes the
736            relevant variables.
738        (b) The debugging options /B and /D in pcretest show the compiled bytecode
739            with length and offset values. This means that the output is different
740            for different internal link sizes. Test 2 is skipped for link sizes
741            other than 2 because of this, bypassing the problem. Unfortunately,
742            there was also a test in test 3 (the locale tests) that used /B and
743            failed for link sizes other than 2. Rather than cut the whole test out,
744            I have added a new /Z option to pcretest that replaces the length and
745            offset values with spaces. This is now used to make test 3 independent
746            of link size. (Test 2 will be tidied up later.)
748    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
749        segmentation fault instead of returning the appropriate error message.
751    15. In multiline mode when the newline sequence was set to "any", the pattern
752        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
753        This doesn't seem right; it now treats the CRLF combination as the line
754        ending, and so does not match in that case. It's only a pattern such as ^$
755        that would hit this one: something like ^ABC$ would have failed after \r
756        and then tried again after \r\n.
758    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
759        in an attempt to make files that differ only in their line terminators
760        compare equal. This works on Linux.
762    17. Under certain error circumstances pcregrep might try to free random memory
763        as it exited. This is now fixed, thanks to valgrind.
765    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
766        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
767        was because its rules for how to advance for /g after matching an empty
768        string at the end of a line did not allow for this case. They now check for
769        it specially.
771    20. pcretest is supposed to handle patterns and data of any length, by
772        extending its buffers when necessary. It was getting this wrong when the
773        buffer for a data line had to be extended.
775    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
776        CRLF as a newline sequence.
778    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
779        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
780        I have nevertheless tidied it up.
782    23. Added some casts to kill warnings from HP-UX ia64 compiler.
784    24. Added a man page for pcre-config.
787    Version 7.0 19-Dec-06
788    ---------------------
790     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
791        moving to gcc 4.1.1.
793     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
794        sys/time.h, which is documented as needed for this function. It doesn't
795        seem to matter on Linux, but it showed up on some releases of OS X.
797     3. It seems that there are systems where bytes whose values are greater than
798        127 match isprint() in the "C" locale. The "C" locale should be the
799        default when a C program starts up. In most systems, only ASCII printing
800        characters match isprint(). This difference caused the output from pcretest
801        to vary, making some of the tests fail. I have changed pcretest so that:
803        (a) When it is outputting text in the compiled version of a pattern, bytes
804            other than 32-126 are always shown as hex escapes.
806        (b) When it is outputting text that is a matched part of a subject string,
807            it does the same, unless a different locale has been set for the match
808            (using the /L modifier). In this case, it uses isprint() to decide.
810     4. Fixed a major bug that caused incorrect computation of the amount of memory
811        required for a compiled pattern when options that changed within the
812        pattern affected the logic of the preliminary scan that determines the
813        length. The relevant options are -x, and -i in UTF-8 mode. The result was
814        that the computed length was too small. The symptoms of this bug were
815        either the PCRE error "internal error: code overflow" from pcre_compile(),
816        or a glibc crash with a message such as "pcretest: free(): invalid next
817        size (fast)". Examples of patterns that provoked this bug (shown in
818        pcretest format) are:
820          /(?-x: )/x
821          /(?x)(?-x: \s*#\s*)/
822          /((?i)[\x{c0}])/8
823          /(?i:[\x{c0}])/8
825        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
826        is now done differently.
828     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
829        wrapper classes; (b) implement a new function in the C++ scanner that is
830        more efficient than the old way of doing things because it avoids levels of
831        recursion in the regex matching; (c) add a paragraph to the documentation
832        for the FullMatch() function.
834     6. The escape sequence \n was being treated as whatever was defined as
835        "newline". Not only was this contrary to the documentation, which states
836        that \n is character 10 (hex 0A), but it also went horribly wrong when
837        "newline" was defined as CRLF. This has been fixed.
839     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
840        was being set to -1 for the "end of line" case (supposedly a value that no
841        character can have). Though this value is never used (the check for end of
842        line is "zero bytes in current character"), it caused compiler complaints.
843        I've changed it to 0xffffffff.
845     8. In pcre_version.c, the version string was being built by a sequence of
846        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
847        string (as it is for production releases) called a macro with an empty
848        argument. The C standard says the result of this is undefined. The gcc
849        compiler treats it as an empty string (which was what was wanted) but it is
850        reported that Visual C gives an error. The source has been hacked around to
851        avoid this problem.
853     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
854        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
855        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
856        of them did).
858    10. Originally, pcretest opened its input and output without "b"; then I was
859        told that "b" was needed in some environments, so it was added for release
860        5.0 to both the input and output. (It makes no difference on Unix-like
861        systems.) Later I was told that it is wrong for the input on Windows. I've
862        now abstracted the modes into two macros, to make it easier to fiddle with
863        them, and removed "b" from the input mode under Windows.
865    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
867    12. Added -help and --help to pcretest as an official way of being reminded
868        of the options.
870    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
871        and pcrecpp.cc because they annoy compilers at high warning levels.
873    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
875    15. Fixed an occurrence of == in configure.ac that should have been = (shell
876        scripts are not C programs :-) and which was not noticed because it works
877        on Linux.
879    16. pcretest is supposed to handle any length of pattern and data line (as one
880        line or as a continued sequence of lines) by extending its input buffer if
881        necessary. This feature was broken for very long pattern lines, leading to
882        a string of junk being passed to pcre_compile() if the pattern was longer
883        than about 50K.
885    17. I have done a major re-factoring of the way pcre_compile() computes the
886        amount of memory needed for a compiled pattern. Previously, there was code
887        that made a preliminary scan of the pattern in order to do this. That was
888        OK when PCRE was new, but as the facilities have expanded, it has become
889        harder and harder to keep it in step with the real compile phase, and there
890        have been a number of bugs (see for example, 4 above). I have now found a
891        cunning way of running the real compile function in a "fake" mode that
892        enables it to compute how much memory it would need, while actually only
893        ever using a few hundred bytes of working memory and without too many
894        tests of the mode. This should make future maintenance and development
895        easier. A side effect of this work is that the limit of 200 on the nesting
896        depth of parentheses has been removed (though this was never a serious
897        limitation, I suspect). However, there is a downside: pcre_compile() now
898        runs more slowly than before (30% or more, depending on the pattern). I
899        hope this isn't a big issue. There is no effect on runtime performance.
901    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
902        newline (only possible for the last line of a file) and it was a
903        pattern that set a locale (followed by /Lsomething), pcretest crashed.
905    19. Added additional timing features to pcretest. (1) The -tm option now times
906        matching only, not compiling. (2) Both -t and -tm can be followed, as a
907        separate command line item, by a number that specifies the number of
908        repeats to use when timing. The default is 50000; this gives better
909        precision, but takes uncomfortably long for very large patterns.
911    20. Extended pcre_study() to be more clever in cases where a branch of a
912        subpattern has no definite first character. For example, (a*|b*)[cd] would
913        previously give no result from pcre_study(). Now it recognizes that the
914        first character must be a, b, c, or d.
916    21. There was an incorrect error "recursive call could loop indefinitely" if
917        a subpattern (or the entire pattern) that was being tested for matching an
918        empty string contained only one non-empty item after a nested subpattern.
919        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
920        incorrectly, because the \d was being skipped in the check.
922    22. The pcretest program now has a new pattern option /B and a command line
923        option -b, which is equivalent to adding /B to every pattern. This causes
924        it to show the compiled bytecode, without the additional information that
925        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
926        is the same as /B/I).
928    23. A new optimization is now able automatically to treat some sequences such
929        as a*b as a*+b. More specifically, if something simple (such as a character
930        or a simple class like \d) has an unlimited quantifier, and is followed by
931        something that cannot possibly match the quantified thing, the quantifier
932        is automatically "possessified".
934    24. A recursive reference to a subpattern whose number was greater than 39
935        went wrong under certain circumstances in UTF-8 mode. This bug could also
936        have affected the operation of pcre_study().
938    25. Realized that a little bit of performance could be had by replacing
939        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
941    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
943    27. Possessive quantifiers such as a++ were previously implemented by turning
944        them into atomic groups such as ($>a+). Now they have their own opcodes,
945        which improves performance. This includes the automatically created ones
946        from 23 above.
948    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
949        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
950        the first matched character to be a colon. This applied both to named and
951        numbered groups.
953    29. The ucpinternal.h header file was missing its idempotency #ifdef.
955    30. I was sent a "project" file called libpcre.a.dev which I understand makes
956        building PCRE on Windows easier, so I have included it in the distribution.
958    31. There is now a check in pcretest against a ridiculously large number being
959        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
960        loop, the loop is abandoned.
962    32. Forward references to subpatterns in conditions such as (?(2)...) where
963        subpattern 2 is defined later cause pcre_compile() to search forwards in
964        the pattern for the relevant set of parentheses. This search went wrong
965        when there were unescaped parentheses in a character class, parentheses
966        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
968    33. "Subroutine" calls and backreferences were previously restricted to
969        referencing subpatterns earlier in the regex. This restriction has now
970        been removed.
972    34. Added a number of extra features that are going to be in Perl 5.10. On the
973        whole, these are just syntactic alternatives for features that PCRE had
974        previously implemented using the Python syntax or my own invention. The
975        other formats are all retained for compatibility.
977        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
978            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
979            also .NET compatible.
981        (b) A recursion or subroutine call to a named group can now be defined as
982            (?&name) as well as (?P>name).
984        (c) A backreference to a named group can now be defined as \k<name> or
985            \k'name' as well as (?P=name). The new forms, as well as being in Perl
986            5.10, are also .NET compatible.
988        (d) A conditional reference to a named group can now use the syntax
989            (?(<name>) or (?('name') as well as (?(name).
991        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
992            groups (named and numbered) that are never evaluated inline, but can be
993            called as "subroutines" from elsewhere. In effect, the DEFINE condition
994            is always false. There may be only one alternative in such a group.
996        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
997            as the simple (?(R). The condition is true only if the most recent
998            recursion is that of the given number or name. It does not search out
999            through the entire recursion stack.
1001        (g) The escape \gN or \g{N} has been added, where N is a positive or
1002            negative number, specifying an absolute or relative reference.
1004    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1005        some "unreachable code" warnings.
1007    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1008        things, this adds five new scripts.
1010    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1011        There were also incompatibilities regarding the handling of \Q..\E inside
1012        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1013        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1015    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1016        matches an empty string, and forcibly breaks the loop. There were bugs in
1017        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1018        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1019        separate and independent bugs (that affected different cases) have been
1020        fixed.
1022    39. Refactored the code to abolish the use of different opcodes for small
1023        capturing bracket numbers. This is a tidy that I avoided doing when I
1024        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1025        The new approach is not only tidier, it makes it possible to reduce the
1026        memory needed to fix the previous bug (38).
1028    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1029        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1030        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1031        mode.
1033    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1034        report.
1036    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1037        copy construction and assignment in the C++ wrapper.
1039    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1040        couple of bugs that could have given wrong results in the "--newline=crlf"
1041        case.
1043    44. Added a number of casts and did some reorganization of signed/unsigned int
1044        variables following suggestions from Dair Grant. Also renamed the variable
1045        "this" as "item" because it is a C++ keyword.
1047    45. Arranged for dftables to add
1049          #include "pcre_internal.h"
1051        to pcre_chartables.c because without it, gcc 4.x may remove the array
1052        definition from the final binary if PCRE is built into a static library and
1053        dead code stripping is activated.
1055    46. For an unanchored pattern, if a match attempt fails at the start of a
1056        newline sequence, and the newline setting is CRLF or ANY, and the next two
1057        characters are CRLF, advance by two characters instead of one.
1060    Version 6.7 04-Jul-06
1061    ---------------------
1063     1. In order to handle tests when input lines are enormously long, pcretest has
1064        been re-factored so that it automatically extends its buffers when
1065        necessary. The code is crude, but this _is_ just a test program. The
1066        default size has been increased from 32K to 50K.
1068     2. The code in pcre_study() was using the value of the re argument before
1069        testing it for NULL. (Of course, in any sensible call of the function, it
1070        won't be NULL.)
1072     3. The memmove() emulation function in pcre_internal.h, which is used on
1073        systems that lack both memmove() and bcopy() - that is, hardly ever -
1074        was missing a "static" storage class specifier.
1076     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1077        containing an extended class (one that cannot be represented by a bitmap
1078        because it contains high-valued characters or Unicode property items, e.g.
1079        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1080        pattern, but PCRE should not loop if you do not (it no longer does).
1081        [Detail: two cases were found: (a) a repeated subpattern containing an
1082        extended class; (b) a recursive reference to a subpattern that followed a
1083        previous extended class. It wasn't skipping over the extended class
1084        correctly when UTF-8 mode was not set.]
1086     5. A negated single-character class was not being recognized as fixed-length
1087        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1088        compile error "lookbehind assertion is not fixed length".
1090     6. The RunPerlTest auxiliary script was showing an unexpected difference
1091        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1092        write a Perl script that can interpret lines of an input file either as
1093        byte characters or as UTF-8, which is what "perltest" was being required to
1094        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1095        can't do is switch easily at run time between having the "use utf8;" pragma
1096        or not. In the end, I fudged it by using the RunPerlTest script to insert
1097        "use utf8;" explicitly for the UTF-8 tests.
1099     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1100        the end of the subject string, contrary to the documentation and to what
1101        Perl does. This was true of both matching functions. Now it matches only at
1102        the start of the subject and immediately after *internal* newlines.
1104     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1105        a pointer to an int instead of a pointer to an unsigned long int. This
1106        caused problems on 64-bit systems.
1108     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1109        instance of the 'standard' template library not being so standard".
1111    10. There was no check on the number of named subpatterns nor the maximum
1112        length of a subpattern name. The product of these values is used to compute
1113        the size of the memory block for a compiled pattern. By supplying a very
1114        long subpattern name and a large number of named subpatterns, the size
1115        computation could be caused to overflow. This is now prevented by limiting
1116        the length of names to 32 characters, and the number of named subpatterns
1117        to 10,000.
1119    11. Subpatterns that are repeated with specific counts have to be replicated in
1120        the compiled pattern. The size of memory for this was computed from the
1121        length of the subpattern and the repeat count. The latter is limited to
1122        65535, but there was no limit on the former, meaning that integer overflow
1123        could in principle occur. The compiled length of a repeated subpattern is
1124        now limited to 30,000 bytes in order to prevent this.
1126    12. Added the optional facility to have named substrings with the same name.
1128    13. Added the ability to use a named substring as a condition, using the
1129        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1130        are numbers (not recommended). Forward references are permitted.
1132    14. Added forward references in named backreferences (if you see what I mean).
1134    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1135        pattern could run off the end of the subject. For example, the pattern
1136        "(?s)(.{1,5})"8 did this with the subject "ab".
1138    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1139        PCRE_CASELESS was set when matching characters that were quantified with ?
1140        or *.
1142    17. A character class other than a single negated character that had a minimum
1143        but no maximum quantifier - for example [ab]{6,} - was not handled
1144        correctly by pce_dfa_exec(). It would match only one character.
1146    18. A valid (though odd) pattern that looked like a POSIX character
1147        class but used an invalid character after [ (for example [[,abc,]]) caused
1148        pcre_compile() to give the error "Failed: internal error: code overflow" or
1149        in some cases to crash with a glibc free() error. This could even happen if
1150        the pattern terminated after [[ but there just happened to be a sequence of
1151        letters, a binary zero, and a closing ] in the memory that followed.
1153    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1154        over the years. Originally (before any Unicode support), just the bottom 8
1155        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1156        output from "man perlunicode" includes this:
1158          The regular expression compiler produces polymorphic opcodes.  That
1159          is, the pattern adapts to the data and automatically switches to
1160          the Unicode character scheme when presented with Unicode data--or
1161          instead uses a traditional byte scheme when presented with byte
1162          data.
1164        Sadly, a wide octal escape does not cause a switch, and in a string with
1165        no other multibyte characters, these octal escapes are treated as before.
1166        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1167        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1168        Unicode string.
1170        I have not perpetrated such confusion in PCRE. Up till now, it took just
1171        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1172        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1173        translate to the appropriate multibyte character.
1175    29. Applied some refactoring to reduce the number of warnings from Microsoft
1176        and Borland compilers. This has included removing the fudge introduced
1177        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1178        a warning about an unused variable.
1180    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1181        characters since release 4.0, because Perl (from release 5.004) does not.
1182        [Or at least, is documented not to: some releases seem to be in conflict
1183        with the documentation.] However, when a pattern was studied with
1184        pcre_study() and all its branches started with \s, PCRE still included VT
1185        as a possible starting character. Of course, this did no harm; it just
1186        caused an unnecessary match attempt.
1188    22. Removed a now-redundant internal flag bit that recorded the fact that case
1189        dependency changed within the pattern. This was once needed for "required
1190        byte" processing, but is no longer used. This recovers a now-scarce options
1191        bit. Also moved the least significant internal flag bit to the most-
1192        significant bit of the word, which was not previously used (hangover from
1193        the days when it was an int rather than a uint) to free up another bit for
1194        the future.
1196    23. Added support for CRLF line endings as well as CR and LF. As well as the
1197        default being selectable at build time, it can now be changed at runtime
1198        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1199        specify that it is scanning data with non-default line endings.
1201    24. Changed the definition of CXXLINK to make it agree with the definition of
1202        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1204    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1205        recursions. This makes a big different to stack usage for some patterns.
1207    26. If a subpattern containing a named recursion or subroutine reference such
1208        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1209        the space required for the compiled pattern went wrong and gave too small a
1210        value. Depending on the environment, this could lead to "Failed: internal
1211        error: code overflow at offset 49" or "glibc detected double free or
1212        corruption" errors.
1214    27. Applied patches from Google (a) to support the new newline modes and (b) to
1215        advance over multibyte UTF-8 characters in GlobalReplace.
1217    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1218        difference for some implementation of PCRE in some Windows version.
1220    29. Added some extra testing facilities to pcretest:
1222        \q<number>   in a data line sets the "match limit" value
1223        \Q<number>   in a data line sets the "match recursion limt" value
1224        -S <number>  sets the stack size, where <number> is in megabytes
1226        The -S option isn't available for Windows.
1229    Version 6.6 06-Feb-06
1230    ---------------------
1232     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1233        in pcreposix.h. I have copied the definition from pcre.h.
1235     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1236        because pcre.h is no longer a built file.
1238     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1239        not normally included in the compiled code.
1242    Version 6.5 01-Feb-06
1243    ---------------------
1245     1. When using the partial match feature with pcre_dfa_exec(), it was not
1246        anchoring the second and subsequent partial matches at the new starting
1247        point. This could lead to incorrect results. For example, with the pattern
1248        /1234/, partially matching against "123" and then "a4" gave a match.
1250     2. Changes to pcregrep:
1252        (a) All non-match returns from pcre_exec() were being treated as failures
1253            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1254            error message is output. Some extra information is given for the
1255            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1256            probably the only errors that are likely to be caused by users (by
1257            specifying a regex that has nested indefinite repeats, for instance).
1258            If there are more than 20 of these errors, pcregrep is abandoned.
1260        (b) A binary zero was treated as data while matching, but terminated the
1261            output line if it was written out. This has been fixed: binary zeroes
1262            are now no different to any other data bytes.
1264        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1265            used to set a locale for matching. The --locale=xxxx long option has
1266            been added (no short equivalent) to specify a locale explicitly on the
1267            pcregrep command, overriding the environment variables.
1269        (d) When -B was used with -n, some line numbers in the output were one less
1270            than they should have been.
1272        (e) Added the -o (--only-matching) option.
1274        (f) If -A or -C was used with -c (count only), some lines of context were
1275            accidentally printed for the final match.
1277        (g) Added the -H (--with-filename) option.
1279        (h) The combination of options -rh failed to suppress file names for files
1280            that were found from directory arguments.
1282        (i) Added the -D (--devices) and -d (--directories) options.
1284        (j) Added the -F (--fixed-strings) option.
1286        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1288        (l) Added the --colo(u)r option.
1290        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1291            is not present by default.
1293     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1294        items such as (?R) or (?1), when the recursion could match a number of
1295        alternatives. If it matched one of the alternatives, but subsequently,
1296        outside the recursion, there was a failure, the code tried to back up into
1297        the recursion. However, because of the way PCRE is implemented, this is not
1298        possible, and the result was an incorrect result from the match.
1300        In order to prevent this happening, the specification of recursion has
1301        been changed so that all such subpatterns are automatically treated as
1302        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1304     4. I had overlooked the fact that, in some locales, there are characters for
1305        which isalpha() is true but neither isupper() nor islower() are true. In
1306        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1307        and ordfeminine) are like this. This affected the treatment of \w and \W
1308        when they appeared in character classes, but not when they appeared outside
1309        a character class. The bit map for "word" characters is now created
1310        separately from the results of isalnum() instead of just taking it from the
1311        upper, lower, and digit maps. (Plus the underscore character, of course.)
1313     5. The above bug also affected the handling of POSIX character classes such as
1314        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1315        permanent tables. Instead, the bit maps for such a class were previously
1316        created as the appropriate unions of the upper, lower, and digit bitmaps.
1317        Now they are created by subtraction from the [[:word:]] class, which has
1318        its own bitmap.
1320     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1321        It is created by subtracting the vertical space characters (\x09, \x0a,
1322        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1323        subtraction was done in the overall bitmap for a character class, meaning
1324        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1325        be recognized. This bug has been fixed.
1327     7. Patches from the folks at Google:
1329          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1330          real life, but is still worth protecting against".
1332          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1333          regular expressions".
1335          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1336          have it.
1338          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1339          "configure" and the latter not, in order to fix a problem somebody had
1340          with compiling the Arg class on HP-UX.
1342          (e) Improve the error-handling of the C++ wrapper a little bit.
1344          (f) New tests for checking recursion limiting.
1346     8. The pcre_memmove() function, which is used only if the environment does not
1347        have a standard memmove() function (and is therefore rarely compiled),
1348        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1349        returning a result (though PCRE never actually uses the result).
1351     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1352        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1353        returned instead of calling malloc() with an overflowing number that would
1354        most likely cause subsequent chaos.
1356    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1358    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1359        with this option is matched, the nmatch and pmatch options of regexec() are
1360        ignored.
1362    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1363        provided in case anyone wants to the the POSIX interface with UTF-8
1364        strings.
1366    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1367        C++ linking (needed for some HP-UX environments).
1369    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1370        (unused parameter) and in the pcre_printint() function (omitted "default"
1371        switch label when the default is to do nothing).
1373    15. Added some code to make it possible, when PCRE is compiled as a C++
1374        library, to replace subject pointers for pcre_exec() with a smart pointer
1375        class, thus making it possible to process discontinuous strings.
1377    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1378        much the same function. They were added by different people who were trying
1379        to make PCRE easy to compile on non-Unix systems. It has been suggested
1380        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1381        for compiling on Windows systems. I have therefore replaced it with
1382        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1383        defaults to "extern" for C or "extern C" for C++, which works fine on
1384        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1385        SCOPE with something explicit in config.h. In addition:
1387        (a) pcreposix.h still had just "extern" instead of either of these macros;
1388            I have replaced it with PCRE_DATA_SCOPE.
1390        (b) Functions such as _pcre_xclass(), which are internal to the library,
1391            but external in the C sense, all had PCRE_EXPORT in their definitions.
1392            This is apparently wrong for the Windows case, so I have removed it.
1393            (It makes no difference on Unix-like systems.)
1395    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1396        of recursive calls to match(). This is different to MATCH_LIMIT because
1397        that limits the total number of calls to match(), not all of which increase
1398        the depth of recursion. Limiting the recursion depth limits the amount of
1399        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1400        when PCRE is compiled, and changed at run time. A patch from Google adds
1401        this functionality to the C++ interface.
1403    18. Changes to the handling of Unicode character properties:
1405        (a) Updated the table to Unicode 4.1.0.
1407        (b) Recognize characters that are not in the table as "Cn" (undefined).
1409        (c) I revised the way the table is implemented to a much improved format
1410            which includes recognition of ranges. It now supports the ranges that
1411            are defined in UnicodeData.txt, and it also amalgamates other
1412            characters into ranges. This has reduced the number of entries in the
1413            table from around 16,000 to around 3,000, thus reducing its size
1414            considerably. I realized I did not need to use a tree structure after
1415            all - a binary chop search is just as efficient. Having reduced the
1416            number of entries, I extended their size from 6 bytes to 8 bytes to
1417            allow for more data.
1419        (d) Added support for Unicode script names via properties such as \p{Han}.
1421    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1422        matching that character.
1424    20. When matching a repeated Unicode property with a minimum greater than zero,
1425        (for example \pL{2,}), PCRE could look past the end of the subject if it
1426        reached it while seeking the minimum number of characters. This could
1427        happen only if some of the characters were more than one byte long, because
1428        there is a check for at least the minimum number of bytes.
1430    21. Refactored the implementation of \p and \P so as to be more general, to
1431        allow for more different types of property in future. This has changed the
1432        compiled form incompatibly. Anybody with saved compiled patterns that use
1433        \p or \P will have to recompile them.
1435    22. Added "Any" and "L&" to the supported property types.
1437    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1438        but give a compile time error if the value is greater than 0xff.
1440    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1441        accidentally not being installed or uninstalled.
1443    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1444        made were to insert the current release number. This seemed silly, because
1445        it made things harder for people building PCRE on systems that don't run
1446        "configure". I have turned pcre.h into a distributed file, no longer built
1447        by "configure", with the version identification directly included. There is
1448        no longer a pcre.h.in file.
1450        However, this change necessitated a change to the pcre-config script as
1451        well. It is built from pcre-config.in, and one of the substitutions was the
1452        release number. I have updated configure.ac so that ./configure now finds
1453        the release number by grepping pcre.h.
1455    26. Added the ability to run the tests under valgrind.
1458    Version 6.4 05-Sep-05
1459    ---------------------
1461     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1462        "--" to be printed when multiple files were scanned, even when none of the
1463        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1464        consider it to be a bug, and have restored the previous behaviour.
1466     2. A couple of code tidies to get rid of compiler warnings.
1468     3. The pcretest program used to cheat by referring to symbols in the library
1469        whose names begin with _pcre_. These are internal symbols that are not
1470        really supposed to be visible externally, and in some environments it is
1471        possible to suppress them. The cheating is now confined to including
1472        certain files from the library's source, which is a bit cleaner.
1474     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1475        file's purpose clearer.
1477     5. Reorganized pcre_ucp_findchar().
1480    Version 6.3 15-Aug-05
1481    ---------------------
1483     1. The file libpcre.pc.in did not have general read permission in the tarball.
1485     2. There were some problems when building without C++ support:
1487        (a) If C++ support was not built, "make install" and "make test" still
1488            tried to test it.
1490        (b) There were problems when the value of CXX was explicitly set. Some
1491            changes have been made to try to fix these, and ...
1493        (c) --disable-cpp can now be used to explicitly disable C++ support.
1495        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1496            backslash in a target when C++ was disabled. This confuses some
1497            versions of "make", apparently. Using an intermediate variable solves
1498            this. (Same for CPP_LOBJ.)
1500     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1501        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1502        necessary on certain architectures.
1504     4. Added a setting of -export-symbols-regex to the link command to remove
1505        those symbols that are exported in the C sense, but actually are local
1506        within the library, and not documented. Their names all begin with
1507        "_pcre_". This is not a perfect job, because (a) we have to except some
1508        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1509        available (and never for static libraries). I have made a note to try to
1510        find a way round (a) in the future.
1513    Version 6.2 01-Aug-05
1514    ---------------------
1516     1. There was no test for integer overflow of quantifier values. A construction
1517        such as {1111111111111111} would give undefined results. What is worse, if
1518        a minimum quantifier for a parenthesized subpattern overflowed and became
1519        negative, the calculation of the memory size went wrong. This could have
1520        led to memory overwriting.
1522     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1524     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1525        operating environments where this matters.
1527     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1528        PCRE options from within the C++ wrapper.
1530     5. Named capturing subpatterns were not being correctly counted when a pattern
1531        was compiled. This caused two problems: (a) If there were more than 100
1532        such subpatterns, the calculation of the memory needed for the whole
1533        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1534        back references of the form \12, where the number was greater than 9, were
1535        not recognized as back references, even though there were sufficient
1536        previous subpatterns.
1538     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1539        versions of gcc, e.g. 2.95.4.
1542    Version 6.1 21-Jun-05
1543    ---------------------
1545     1. There was one reference to the variable "posix" in pcretest.c that was not
1546        surrounded by "#if !defined NOPOSIX".
1548     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1549        the cross-check on the old pcre_info() function, for the benefit of the
1550        cut-down version of PCRE that is currently imported into Exim.
1552     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1553        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1554        patterns that start (?i) but I don't think that matters. The use of (?i) is
1555        just an example; this all applies to the other options as well.
1557     4. Since libtool seems to echo the compile commands it is issuing, the output
1558        from "make" can be reduced a bit by putting "@" in front of each libtool
1559        compile command.
1561     5. Patch from the folks at Google for configure.in to be a bit more thorough
1562        in checking for a suitable C++ installation before trying to compile the
1563        C++ stuff. This should fix a reported problem when a compiler was present,
1564        but no suitable headers.
1566     6. The man pages all had just "PCRE" as their title. I have changed them to
1567        be the relevant file name. I have also arranged that these names are
1568        retained in the file doc/pcre.txt, which is a concatenation in text format
1569        of all the man pages except the little individual ones for each function.
1571     7. The NON-UNIX-USE file had not been updated for the different set of source
1572        files that come with release 6. I also added a few comments about the C++
1573        wrapper.
1576    Version 6.0 07-Jun-05
1577    ---------------------
1579     1. Some minor internal re-organization to help with my DFA experiments.
1581     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1582        didn't matter for the library itself when fully configured, but did matter
1583        when compiling without UCP support, or within Exim, where the ucp files are
1584        not imported.
1586     3. Refactoring of the library code to split up the various functions into
1587        different source modules. The addition of the new DFA matching code (see
1588        below) to a single monolithic source would have made it really too
1589        unwieldy, quite apart from causing all the code to be include in a
1590        statically linked application, when only some functions are used. This is
1591        relevant even without the DFA addition now that patterns can be compiled in
1592        one application and matched in another.
1594        The downside of splitting up is that there have to be some external
1595        functions and data tables that are used internally in different modules of
1596        the library but which are not part of the API. These have all had their
1597        names changed to start with "_pcre_" so that they are unlikely to clash
1598        with other external names.
1600     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1601        a different (DFA) algorithm. Although it is slower than the original
1602        function, it does have some advantages for certain types of matching
1603        problem.
1605     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1606        including restarting after a partial match.
1608     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1609        defined when compiling for Windows was sent to me. I have put it into the
1610        code, though I have no means of testing or verifying it.
1612     7. Added the pcre_refcount() auxiliary function.
1614     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1615        match before or at the first newline in the subject string. In pcretest,
1616        the /f option on a pattern can be used to set this.
1618     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1619        would behave wrongly. This has been present in PCRE since release 4.0.
1621    10. A number of changes to the pcregrep command:
1623        (a) Refactored how -x works; insert ^(...)$ instead of setting
1624            PCRE_ANCHORED and checking the length, in preparation for adding
1625            something similar for -w.
1627        (b) Added the -w (match as a word) option.
1629        (c) Refactored the way lines are read and buffered so as to have more
1630            than one at a time available.
1632        (d) Implemented a pcregrep test script.
1634        (e) Added the -M (multiline match) option. This allows patterns to match
1635            over several lines of the subject. The buffering ensures that at least
1636            8K, or the rest of the document (whichever is the shorter) is available
1637            for matching (and similarly the previous 8K for lookbehind assertions).
1639        (f) Changed the --help output so that it now says
1641              -w, --word-regex(p)
1643            instead of two lines, one with "regex" and the other with "regexp"
1644            because that confused at least one person since the short forms are the
1645            same. (This required a bit of code, as the output is generated
1646            automatically from a table. It wasn't just a text change.)
1648        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1649            option but starts with a hyphen. Could be a pattern or a path name
1650            starting with a hyphen, for instance.
1652        (h) "-" can be given as a file name to represent stdin.
1654        (i) When file names are being printed, "(standard input)" is used for
1655            the standard input, for compatibility with GNU grep. Previously
1656            "<stdin>" was used.
1658        (j) The option --label=xxx can be used to supply a name to be used for
1659            stdin when file names are being printed. There is no short form.
1661        (k) Re-factored the options decoding logic because we are going to add
1662            two more options that take data. Such options can now be given in four
1663            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1665        (l) Added the -A, -B, and -C options for requesting that lines of context
1666            around matches be printed.
1668        (m) Added the -L option to print the names of files that do not contain
1669            any matching lines, that is, the complement of -l.
1671        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1672            continue to scan other files.
1674        (o) The -s option was incorrectly implemented. For compatibility with other
1675            greps, it now suppresses the error message for a non-existent or non-
1676            accessible file (but not the return code). There is a new option called
1677            -q that suppresses the output of matching lines, which was what -s was
1678            previously doing.
1680        (p) Added --include and --exclude options to specify files for inclusion
1681            and exclusion when recursing.
1683    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1684        Hopefully, it now does.
1686    12. Missing cast in pcre_study().
1688    13. Added an "uninstall" target to the makefile.
1690    14. Replaced "extern" in the function prototypes in Makefile.in with
1691        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1692        world, but is set differently for Windows.
1694    15. Added a second compiling function called pcre_compile2(). The only
1695        difference is that it has an extra argument, which is a pointer to an
1696        integer error code. When there is a compile-time failure, this is set
1697        non-zero, in addition to the error test pointer being set to point to an
1698        error message. The new argument may be NULL if no error number is required
1699        (but then you may as well call pcre_compile(), which is now just a
1700        wrapper). This facility is provided because some applications need a
1701        numeric error indication, but it has also enabled me to tidy up the way
1702        compile-time errors are handled in the POSIX wrapper.
1704    16. Added VPATH=.libs to the makefile; this should help when building with one
1705        prefix path and installing with another. (Or so I'm told by someone who
1706        knows more about this stuff than I do.)
1708    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1709        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1710        match everything, including newlines. This is not POSIX-compatible, but
1711        somebody wanted the feature. From pcretest it can be activated by using
1712        both the P and the s flags.
1714    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1716    19. libpcre.pc was being incorrectly installed as executable.
1718    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1719        it now also looks for '\r' so that it will work unmodified on Windows.
1721    21. Added Google's contributed C++ wrapper to the distribution.
1723    22. Added some untidy missing memory free() calls in pcretest, to keep
1724        Electric Fence happy when testing.
1728    Version 5.0 13-Sep-04
1729    ---------------------
1731     1. Internal change: literal characters are no longer packed up into items
1732        containing multiple characters in a single byte-string. Each character
1733        is now matched using a separate opcode. However, there may be more than one
1734        byte in the character in UTF-8 mode.
1736     2. The pcre_callout_block structure has two new fields: pattern_position and
1737        next_item_length. These contain the offset in the pattern to the next match
1738        item, and its length, respectively.
1740     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1741        insertion of callouts before each pattern item. Added the /C option to
1742        pcretest to make use of this.
1744     4. On the advice of a Windows user, the lines
1746          #if defined(_WIN32) || defined(WIN32)
1747          _setmode( _fileno( stdout ), 0x8000 );
1748          #endif  /* defined(_WIN32) || defined(WIN32) */
1750        have been added to the source of pcretest. This apparently does useful
1751        magic in relation to line terminators.
1753     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1754        for the benefit of those environments where the "b" makes a difference.
1756     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1757        to know about it. I have put a hack into configure.in that adds in code
1758        to set GCC=yes if CC=icc. This seems to end up at a point in the
1759        generated configure script that is early enough to affect the setting of
1760        compiler options, which is what is needed, but I have no means of testing
1761        whether it really works. (The user who reported this had patched the
1762        generated configure script, which of course I cannot do.)
1764        LATER: After change 22 below (new libtool files), the configure script
1765        seems to know about icc (and also ecc). Therefore, I have commented out
1766        this hack in configure.in.
1768     7. Added support for pkg-config (2 patches were sent in).
1770     8. Negated POSIX character classes that used a combination of internal tables
1771        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1772        [[:^ascii]]. Typically, they would match almost any characters. The other
1773        POSIX classes were not broken in this way.
1775     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1776        to find the match, as PCRE was deluded into thinking that the match had to
1777        start at the start point or following a newline. The same bug applied to
1778        patterns with negative forward assertions or any backward assertions
1779        preceding ".*" at the start, unless the pattern required a fixed first
1780        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1782    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1783        starting at the last subject character, bytes beyond the end of the subject
1784        string were read.
1786    11. Renamed the variable "class" as "classbits" to make life easier for C++
1787        users. (Previously there was a macro definition, but it apparently wasn't
1788        enough.)
1790    12. Added the new field "tables" to the extra data so that tables can be passed
1791        in at exec time, or the internal tables can be re-selected. This allows
1792        a compiled regex to be saved and re-used at a later time by a different
1793        program that might have everything at different addresses.
1795    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1796        -R library as well as a -L library.
1798    14. The debugging options of pcretest (-d on the command line or D on a
1799        pattern) showed incorrect output for anything following an extended class
1800        that contained multibyte characters and which was followed by a quantifier.
1802    15. Added optional support for general category Unicode character properties
1803        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1804        support. It adds about 90K to the size of the library. The meanings of the
1805        inbuilt class escapes such as \d and \s have NOT been changed.
1807    16. Updated pcredemo.c to include calls to free() to release the memory for the
1808        compiled pattern.
1810    17. The generated file chartables.c was being created in the source directory
1811        instead of in the building directory. This caused the build to fail if the
1812        source directory was different from the building directory, and was
1813        read-only.
1815    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1816        file. No doubt somebody will tell me if they don't make sense... Also added
1817        Dan Mooney's comments about building on OpenVMS.
1819    19. Added support for partial matching via the PCRE_PARTIAL option for
1820        pcre_exec() and the \P data escape in pcretest.
1822    20. Extended pcretest with 3 new pattern features:
1824        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1825              write the compiled pattern to the file whose name is "rest-of-line".
1826              This is a straight binary dump of the data, with the saved pointer to
1827              the character tables forced to be NULL. The study data, if any, is
1828              written too. After writing, pcretest reads a new pattern.
1830        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1831              compiled pattern from the given file. There must not be any
1832              occurrences of "<" in the file name (pretty unlikely); if there are,
1833              pcretest will instead treat the initial "<" as a pattern delimiter.
1834              After reading in the pattern, pcretest goes on to read data lines as
1835              usual.
1837        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1838              and 16-bit fields in a compiled pattern, to simulate a pattern that
1839              was compiled on a host of opposite endianness.
1841    21. The pcre-exec() function can now cope with patterns that were compiled on
1842        hosts of opposite endianness, with this restriction:
1844          As for any compiled expression that is saved and used later, the tables
1845          pointer field cannot be preserved; the extra_data field in the arguments
1846          to pcre_exec() should be used to pass in a tables address if a value
1847          other than the default internal tables were used at compile time.
1849    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1850        now diagnosed as an error. Previously, most of the time, a negative number
1851        would have been treated as zero, but if in addition "ovector" was passed as
1852        NULL, a crash could occur.
1854    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1855        new versions from the libtool 1.5 distribution (the last one is a copy of
1856        a file called libtool.m4). This seems to have fixed the need to patch
1857        "configure" to support Darwin 1.3 (which I used to do). However, I still
1858        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1859        workstation).
1861    24. Changed the PCRE licence to be the more standard "BSD" licence.
1864    Version 4.5 01-Dec-03
1865    ---------------------
1867     1. There has been some re-arrangement of the code for the match() function so
1868        that it can be compiled in a version that does not call itself recursively.
1869        Instead, it keeps those local variables that need separate instances for
1870        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1871        needs to "recurse". Keeping track of where control must go is done by means
1872        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1873        hide most of the details from the main code, and operates only if
1874        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1875        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1876        operating.
1878        To make it easier for callers to provide specially tailored get/free
1879        functions for this usage, two new functions, pcre_stack_malloc, and
1880        pcre_stack_free, are used. They are always called in strict stacking order,
1881        and the size of block requested is always the same.
1883        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1884        PCRE has been compiled to use the stack or the heap for recursion. The
1885        -C option of pcretest uses this to show which version is compiled.
1887        A new data escape \S, is added to pcretest; it causes the amounts of store
1888        obtained and freed by both kinds of malloc/free at match time to be added
1889        to the output.
1891     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1892        what's available on my current Linux desktop machine.
1894     3. When matching a UTF-8 string, the test for a valid string at the start has
1895        been extended. If start_offset is not zero, PCRE now checks that it points
1896        to a byte that is the start of a UTF-8 character. If not, it returns
1897        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1898        this is necessary because there may be backward assertions in the pattern.
1899        When matching the same subject several times, it may save resources to use
1900        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1902     4. The code for checking the validity of UTF-8 strings has been tightened so
1903        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1904        containing "overlong sequences".
1906     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1907        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1908        should have been "&", but it just so happened that all the cases this let
1909        through by mistake were picked up later in the function.
1911     6. I had used a variable called "isblank" - this is a C99 function, causing
1912        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1914     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1915        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1916        so the version is shown; (c) stop "make test" echoing "./RunTest".
1918     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1920     9. The prototype for memmove() for systems that don't have it was using
1921        size_t, but the inclusion of the header that defines size_t was later. I've
1922        moved the #includes for the C headers earlier to avoid this.
1924    10. Added some adjustments to the code to make it easier to compiler on certain
1925        special systems:
1927          (a) Some "const" qualifiers were missing.
1928          (b) Added the macro EXPORT before all exported functions; by default this
1929              is defined to be empty.
1930          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1931              that it reads its output file name as an argument instead of writing
1932              to the standard output and assuming this can be redirected.
1934    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1935        class containing characters with values greater than 255, PCRE compilation
1936        went into a loop.
1938    12. A recursive reference to a subpattern that was within another subpattern
1939        that had a minimum quantifier of zero caused PCRE to crash. For example,
1940        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1941        recursion. If the recursively-called subpattern itself had a zero repeat,
1942        that was OK.
1944    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1945        buffer into which it was copied (for escape processing) was still set at
1946        1024, so long lines caused crashes.
1948    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1949        "internal error: code overflow...". This applied to any character class
1950        that was followed by a possessive quantifier.
1952    15. Modified the Makefile to add libpcre.la as a prerequisite for
1953        libpcreposix.la because I was told this is needed for a parallel build to
1954        work.
1956    16. If a pattern that contained .* following optional items at the start was
1957        studied, the wrong optimizing data was generated, leading to matching
1958        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1959        matching string must start with a or b or c. The correct conclusion for
1960        this pattern is that a match can start with any character.
1963    Version 4.4 13-Aug-03
1964    ---------------------
1966     1. In UTF-8 mode, a character class containing characters with values between
1967        127 and 255 was not handled correctly if the compiled pattern was studied.
1968        In fixing this, I have also improved the studying algorithm for such
1969        classes (slightly).
1971     2. Three internal functions had redundant arguments passed to them. Removal
1972        might give a very teeny performance improvement.
1974     3. Documentation bug: the value of the capture_top field in a callout is *one
1975        more than* the number of the hightest numbered captured substring.
1977     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1978        in incorrectly linking with a previously installed version. They now link
1979        explicitly with libpcre.la.
1981     5. configure.in no longer needs to recognize Cygwin specially.
1983     6. A problem in pcre.in for Windows platforms is fixed.
1985     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1986        pcretest, it used to include the size of the study block as part of its
1987        output. Unfortunately, the structure contains a field that has a different
1988        size on different hardware architectures. This meant that the tests that
1989        showed this size failed. As the block is currently always of a fixed size,
1990        this information isn't actually particularly useful in pcretest output, so
1991        I have just removed it.
1993     8. Three pre-processor statements accidentally did not start in column 1.
1994        Sadly, there are *still* compilers around that complain, even though
1995        standard C has not required this for well over a decade. Sigh.
1997     9. In pcretest, the code for checking callouts passed small integers in the
1998        callout_data field, which is a void * field. However, some picky compilers
1999        complained about the casts involved for this on 64-bit systems. Now
2000        pcretest passes the address of the small integer instead, which should get
2001        rid of the warnings.
2003    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2004        both compile and run time, and gives an error if an invalid UTF-8 sequence
2005        is found. There is a option for disabling this check in cases where the
2006        string is known to be correct and/or the maximum performance is wanted.
2008    11. In response to a bug report, I changed one line in Makefile.in from
2010            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2011        to
2012            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2014        to look similar to other lines, but I have no way of telling whether this
2015        is the right thing to do, as I do not use Windows. No doubt I'll get told
2016        if it's wrong...
2019    Version 4.3 21-May-03
2020    ---------------------
2022    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2023       Makefile.
2025    2. Some refactoring to improve the quality of the code:
2027       (i)   The utf8_table... variables are now declared "const".
2029       (ii)  The code for \cx, which used the "case flipping" table to upper case
2030             lower case letters, now just substracts 32. This is ASCII-specific,
2031             but the whole concept of \cx is ASCII-specific, so it seems
2032             reasonable.
2034       (iii) PCRE was using its character types table to recognize decimal and
2035             hexadecimal digits in the pattern. This is silly, because it handles
2036             only 0-9, a-f, and A-F, but the character types table is locale-
2037             specific, which means strange things might happen. A private
2038             table is now used for this - though it costs 256 bytes, a table is
2039             much faster than multiple explicit tests. Of course, the standard
2040             character types table is still used for matching digits in subject
2041             strings against \d.
2043       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2044             ending in _t are). So I've renamed it as ESC_tee.
2046    3. The first argument for regexec() in the POSIX wrapper should have been
2047       defined as "const".
2049    4. Changed pcretest to use malloc() for its buffers so that they can be
2050       Electric Fenced for debugging.
2052    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2053       to read one or more bytes before the start of the subject string. Often this
2054       had no effect on PCRE's behaviour, but in some circumstances it could
2055       provoke a segmentation fault.
2057    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2058       to try to read one or more bytes before the start of the subject string.
2060    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2061       UTF-8 support could misbehave in various ways if the subject string
2062       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2063       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2064       back over UTF-8 characters.)
2067    Version 4.2 14-Apr-03
2068    ---------------------
2070    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2072    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2073         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2074         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2075         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2076         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2077           and BUILD_EXEEXT
2078         Note: automatic setting of the BUILD variables is not yet working
2079         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2080           compile-time but not at link-time
2081         [LINK]: use for linking executables only
2082         make different versions for Windows and non-Windows
2083         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2084           libraries
2085         [LINK_FOR_BUILD]: new variable
2086         [OBJEXT]: use throughout
2087         [EXEEXT]: use throughout
2088         <winshared>: new target
2089         <wininstall>: new target
2090         <dftables.o>: use native compiler
2091         <dftables>: use native linker
2092         <install>: handle Windows platform correctly
2093         <clean>: ditto
2094         <check>: ditto
2095         copy DLL to top builddir before testing
2097       As part of these changes, -no-undefined was removed again. This was reported
2098       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2099       in any case.
2101    3. Some tidies to get rid of compiler warnings:
2103       . In the match_data structure, match_limit was an unsigned long int, whereas
2104         match_call_count was an int. I've made them both unsigned long ints.
2106       . In pcretest the fact that a const uschar * doesn't automatically cast to
2107         a void * provoked a warning.
2109       . Turning on some more compiler warnings threw up some "shadow" variables
2110         and a few more missing casts.
2112    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2113       option, a class that contained a single character with a value between 128
2114       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2116    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2117       option, a class that contained several characters, but with at least one
2118       whose value was between 128 and 255 caused PCRE to crash.
2121    Version 4.1 12-Mar-03
2122    ---------------------
2124    1. Compiling with gcc -pedantic found a couple of places where casts were
2125    needed, and a string in dftables.c that was longer than standard compilers are
2126    required to support.
2128    2. Compiling with Sun's compiler found a few more places where the code could
2129    be tidied up in order to avoid warnings.
2131    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2132    first of these names is deprecated in the latest Autoconf in favour of the name
2133    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2134    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2135    analogy I have changed it to CFLAGS_FOR_BUILD.
2137    4. Added -no-undefined to the linking command in the Makefile, because this is
2138    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2139    linking step for the pcreposix library.
2141    5. PCRE was failing to diagnose the case of two named groups with the same
2142    name.
2144    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2145    literal character that is needed in the subject for a match, and scans along to
2146    ensure that it is present before embarking on the full matching process. This
2147    saves time in cases of nested unlimited repeats that are never going to match.
2148    Problem: the scan can take a lot of time if the subject is very long (e.g.
2149    megabytes), thus penalizing straightforward matches. It is now done only if the
2150    amount of subject to be scanned is less than 1000 bytes.
2152    7. A lesser problem with the same optimization is that it was recording the
2153    first character of an anchored pattern as "needed", thus provoking a search
2154    right along the subject, even when the first match of the pattern was going to
2155    fail. The "needed" character is now not set for anchored patterns, unless it
2156    follows something in the pattern that is of non-fixed length. Thus, it still
2157    fulfils its original purpose of finding quick non-matches in cases of nested
2158    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2161    Version 4.0 17-Feb-03
2162    ---------------------
2164    1. If a comment in an extended regex that started immediately after a meta-item
2165    extended to the end of string, PCRE compiled incorrect data. This could lead to
2166    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2168    2. Moved to autoconf 2.53 and libtool 1.4.2.
2170    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2171    the special perltest8 script is no longer needed - all the tests can be run
2172    from a single perltest script.
2174    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2175    by \s. It has now been removed in PCRE. This means it isn't recognized as
2176    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2177    class [:space:] *does* include VT, thereby creating a mess.
2179    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2180    space and tab.
2182    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2183    its new features into the main test script, reducing the number of scripts.
2185    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2186    were backward compatible, and made the (?i) apply to the whole pattern, as if
2187    /i were given. Now it behaves more logically, and applies the option setting
2188    only to what follows. PCRE has been changed to follow suit. However, if it
2189    finds options settings right at the start of the pattern, it extracts them into
2190    the global options, as before. Thus, they show up in the info data.
2192    8. Added support for the \Q...\E escape sequence. Characters in between are
2193    treated as literals. This is slightly different from Perl in that $ and @ are
2194    also handled as literals inside the quotes. In Perl, they will cause variable
2195    interpolation. Note the following examples:
2197        Pattern            PCRE matches      Perl matches
2199        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2200        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2201        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2203    For compatibility with Perl, \Q...\E sequences are recognized inside character
2204    classes as well as outside them.
2206    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2207    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2208    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2209    signed/unsigned warnings.
2211    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2212    option for pcretest, so I've replaced it by a simple function that does just
2213    that job.
2215    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2216    "pcregrep -".
2218    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2219    Java package. This provides some syntactic sugar for simple cases of what my
2220    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2221    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2222    item, you can use this simplified notation. Note that only makes sense with
2223    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2224    greediness, whatever the setting of the PCRE_UNGREEDY option.
2226    13. A change of greediness default within a pattern was not taking effect at
2227    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2228    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2229    was abstracted outside.
2231    14. PCRE now supports the \G assertion. It is true when the current matching
2232    position is at the start point of the match. This differs from \A when the
2233    starting offset is non-zero. Used with the /g option of pcretest (or similar
2234    code), it works in the same way as it does for Perl's /g option. If all
2235    alternatives of a regex begin with \G, the expression is anchored to the start
2236    match position, and the "anchored" flag is set in the compiled expression.
2238    15. Some bugs concerning the handling of certain option changes within patterns
2239    have been fixed. These applied to options other than (?ims). For example,
2240    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2241    been the other way round. Some of this was related to change 7 above.
2243    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2244    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2245    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2246    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2248    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2249    mode. Unlike ".", it always matches newline, whatever the setting of
2250    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2251    assertions. Perl allows it, but it doesn't (in general) work because it can't
2252    calculate the length of the lookbehind. At least, that's the case for Perl
2253    5.8.0 - I've been told they are going to document that it doesn't work in
2254    future.
2256    18. Added an error diagnosis for escapes that PCRE does not support: these are
2257    \L, \l, \N, \P, \p, \U, \u, and \X.
2259    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2260    reading past the end of the pattern in cases such as /[abcd/.
2262    20. PCRE was getting more memory than necessary for patterns with classes that
2263    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2265    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2266    compiling PCRE for use with Virtual Pascal.
2268    22. Small fix to the Makefile to make it work properly if the build is done
2269    outside the source tree.
2271    23. Added a new extension: a condition to go with recursion. If a conditional
2272    subpattern starts with (?(R) the "true" branch is used if recursion has
2273    happened, whereas the "false" branch is used only at the top level.
2275    24. When there was a very long string of literal characters (over 255 bytes
2276    without UTF support, over 250 bytes with UTF support), the computation of how
2277    much memory was required could be incorrect, leading to segfaults or other
2278    strange effects.
2280    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2281    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2282    there was a subsequent back reference to those brackets. This meant that, for
2283    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2284    possible to check for precisely this case. All we can do is abandon the
2285    optimization if .* occurs inside capturing brackets when there are any back
2286    references whatsoever. (See below for a better fix that came later.)
2288    26. The handling of the optimization for finding the first character of a
2289    non-anchored pattern, and for finding a character that is required later in the
2290    match were failing in some cases. This didn't break the matching; it just
2291    failed to optimize when it could. The way this is done has been re-implemented.
2293    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2295    28. Added a new feature that provides some of the functionality that Perl
2296    provides with (?{...}). The facility is termed a "callout". The way it is done
2297    in PCRE is for the caller to provide an optional function, by setting
2298    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2299    global variable. By default it is unset, which disables all calling out. To get
2300    the function called, the regex must include (?C) at appropriate points. This
2301    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2302    This provides a means of identifying different callout points. When PCRE
2303    reaches such a point in the regex, if pcre_callout has been set, the external
2304    function is called. It is provided with data in a structure called
2305    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2306    matching continues; if it returns a non-zero value, the match at the current
2307    point fails. However, backtracking will occur if possible. [This was changed
2308    later and other features added - see item 49 below.]
2310    29. pcretest is upgraded to test the callout functionality. It provides a
2311    callout function that displays information. By default, it shows the start of
2312    the match and the current position in the text. There are some new data escapes
2313    to vary what happens:
2315        \C+         in addition, show current contents of captured substrings
2316        \C-         do not supply a callout function
2317        \C!n        return 1 when callout number n is reached
2318        \C!n!m      return 1 when callout number n is reached for the mth time
2320    30. If pcregrep was called with the -l option and just a single file name, it
2321    output "<stdin>" if a match was found, instead of the file name.
2323    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2324    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2325    pcre_exec(). This saves a malloc/free per call. The default value of
2326    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2327    when configuring.
2329    32. The default maximum size of a compiled pattern is 64K. There have been a
2330    few cases of people hitting this limit. The code now uses macros to handle the
2331    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2332    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2333    configuring. Tests 2 and 5 work only with 2-byte links because they output
2334    debugging information about compiled patterns.
2336    33. Internal code re-arrangements:
2338    (a) Moved the debugging function for printing out a compiled regex into
2339        its own source file (printint.c) and used #include to pull it into
2340        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2341        separate copies.
2343    (b) Defined the list of op-code names for debugging as a macro in
2344        internal.h so that it is next to the definition of the opcodes.
2346    (c) Defined a table of op-code lengths for simpler skipping along compiled
2347        code. This is again a macro in internal.h so that it is next to the
2348        definition of the opcodes.
2350    34. Added support for recursive calls to individual subpatterns, along the
2351    lines of Robin Houston's patch (but implemented somewhat differently).
2353    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2354    allow it to read and process whole directories in Win32. This code was
2355    contributed by Lionel Fourquaux; it has not been tested by me.
2357    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2358    used to name a group. Names consist of alphanumerics and underscores, and must
2359    be unique. Back references use the syntax (?P=name) and recursive calls use
2360    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2361    numbers. The function pcre_fullinfo() can be used after compilation to extract
2362    a name/number map. There are three relevant calls:
2364      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2365      PCRE_INFO_NAMECOUNT            yields the number of entries
2366      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2368    The map is a vector of fixed-size entries. The size of each entry depends on
2369    the length of the longest name used. The first two bytes of each entry are the
2370    group number, most significant byte first. There follows the corresponding
2371    name, zero terminated. The names are in alphabetical order.
2373    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2374    case instead of 255. Making it the same both with and without UTF-8 support
2375    means that the same test output works with both.
2377    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2378    calling malloc() with a zero argument.
2380    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2381    optimization. I've improved things by keeping a bitmap of backreferences with
2382    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2383    fact referenced, the optimization can be applied. It is unlikely that a
2384    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2385    the match to follow \n) will appear inside brackets with a number greater than
2386    31, but if it does, any back reference > 31 suppresses the optimization.
2388    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2389    of disabling numbered capturing parentheses. Any opening parenthesis that is
2390    not followed by ? behaves as if it were followed by ?: but named parentheses
2391    can still be used for capturing (and they will acquire numbers in the usual
2392    way).
2394    41. Redesigned the return codes from the match() function into yes/no/error so
2395    that errors can be passed back from deep inside the nested calls. A malloc
2396    failure while inside a recursive subpattern call now causes the
2397    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2399    42. It is now possible to set a limit on the number of times the match()
2400    function is called in a call to pcre_exec(). This facility makes it possible to
2401    limit the amount of recursion and backtracking, though not in a directly
2402    obvious way, because the match() function is used in a number of different
2403    circumstances. The count starts from zero for each position in the subject
2404    string (for non-anchored patterns). The default limit is, for compatibility, a
2405    large number, namely 10 000 000. You can change this in two ways:
2407    (a) When configuring PCRE before making, you can use --with-match-limit=n
2408        to set a default value for the compiled library.
2410    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2411        a different value is set. See 45 below.
2413    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2415    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2416    of things that can be changed at compile time. The first argument specifies
2417    what is wanted and the second points to where the information is to be placed.
2418    The current list of available information is:
2420      PCRE_CONFIG_UTF8
2422    The output is an integer that is set to one if UTF-8 support is available;
2423    otherwise it is set to zero.
2427    The output is an integer that it set to the value of the code that is used for
2428    newline. It is either LF (10) or CR (13).
2432    The output is an integer that contains the number of bytes used for internal
2433    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2437    The output is an integer that contains the threshold above which the POSIX
2438    interface uses malloc() for output vectors. See item 31 above.
2442    The output is an unsigned integer that contains the default limit of the number
2443    of match() calls in a pcre_exec() execution. See 42 above.
2445    44. pcretest has been upgraded by the addition of the -C option. This causes it
2446    to extract all the available output from the new pcre_config() function, and to
2447    output it. The program then exits immediately.
2449    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2450    order to support additional features. One way would have been to define
2451    pcre_exec2() (for example) with extra arguments, but this would not have been
2452    extensible, and would also have required all calls to the original function to
2453    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2454    is used for passing in "extra" data from pcre_study().
2456    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2457    contains the following fields:
2459      flags         a bitmap indicating which of the following fields are set
2460      study_data    opaque data from pcre_study()
2461      match_limit   a way of specifying a limit on match() calls for a specific
2462                      call to pcre_exec()
2463      callout_data  data for callouts (see 49 below)
2465    The flag bits are also defined in pcre.h, and are
2471    The pcre_study() function now returns one of these new pcre_extra blocks, with
2472    the actual study data pointed to by the study_data field, and the
2473    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2474    before. That is, this change is entirely upwards-compatible and requires no
2475    change to existing code.
2477    If you want to pass in additional data to pcre_exec(), you can either place it
2478    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2479    block.
2481    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2482    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2483    times with different match limits, until it finds the minimum value needed for
2484    pcre_exec() to complete. The value is then output. This can be instructive; for
2485    most simple matches the number is quite small, but for pathological cases it
2486    gets very large very quickly.
2488    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2489    returns the size of the data block pointed to by the study_data field in a
2490    pcre_extra block, that is, the value that was passed as the argument to
2491    pcre_malloc() when PCRE was getting memory in which to place the information
2492    created by pcre_study(). The fourth argument should point to a size_t variable.
2493    pcretest has been extended so that this information is shown after a successful
2494    pcre_study() call when information about the compiled regex is being displayed.
2496    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2497    because what follows is always an absolute path. (Later: it turns out that this
2498    is more than cosmetic for MinGW, because it doesn't like empty path
2499    components.)
2501    49. Some changes have been made to the callout feature (see 28 above):
2503    (i)  A callout function now has three choices for what it returns:
2505           0  =>  success, carry on matching
2506         > 0  =>  failure at this point, but backtrack if possible
2507         < 0  =>  serious error, return this value from pcre_exec()
2509         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2510         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2511         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2512         use by callout functions. It will never be used by PCRE itself.
2514    (ii) The pcre_extra structure (see 45 above) has a void * field called
2515         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2516         pcre_callout_block structure has a field of the same name. The contents of
2517         the field passed in the pcre_extra structure are passed to the callout
2518         function in the corresponding field in the callout block. This makes it
2519         easier to use the same callout-containing regex from multiple threads. For
2520         testing, the pcretest program has a new data escape
2522           \C*n        pass the number n (may be negative) as callout_data
2524         If the callout function in pcretest receives a non-zero value as
2525         callout_data, it returns that value.
2527    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2528    there were some redundant $(CFLAGS) in commands that are now specified as
2529    $(LINK), which already includes $(CFLAGS).
2531    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2532    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2533    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2534    one-byte characters throughout. Note that case-insensitive matching applies
2535    only to characters whose values are less than 256. PCRE doesn't support the
2536    notion of cases for higher-valued characters.
2538    (i)   A character class whose characters are all within 0-255 is handled as
2539          a bit map, and the map is inverted for negative classes. Previously, a
2540          character > 255 always failed to match such a class; however it should
2541          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2543    (ii)  A negated character class with a single character < 255 is coded as
2544          "not this character" (OP_NOT). This wasn't working properly when the test
2545          character was multibyte, either singly or repeated.
2547    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2548          mode, for example: \x{100}{2,3}.
2550    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2551          singly or repeated) now correctly test multibyte characters. However,
2552          PCRE doesn't recognize any characters with values greater than 255 as
2553          digits, spaces, or word characters. Such characters always match \D, \S,
2554          and \W, and never match \d, \s, or \w.
2556    (v)   Classes may now contain characters and character ranges with values
2557          greater than 255. For example: [ab\x{100}-\x{400}].
2559    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2560          PCRE in UTF-8 mode.
2562    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2563    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2564    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2565    value.)
2567    53. The single man page has become too large. I have therefore split it up into
2568    a number of separate man pages. These also give rise to individual HTML pages;
2569    these are now put in a separate directory, and there is an index.html page that
2570    lists them all. Some hyperlinking between the pages has been installed.
2572    54. Added convenience functions for handling named capturing parentheses.
2574    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2575    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2576    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2577    are faulted.
2579    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2580    calling configure. These values are used when compiling the dftables.c program
2581    which is run to generate the source of the default character tables. They
2582    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2583    you will need to set these values.
2585    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2588    Version 3.9 02-Jan-02
2589  ---------------------  ---------------------
2591  1. A bit of extraneous text had somehow crept into the pcregrep documentation.  1. A bit of extraneous text had somehow crept into the pcregrep documentation.

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