ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 49 by nigel, Sat Feb 24 21:39:33 2007 UTC revision 351 by ph10, Fri Jul 4 18:27:16 2008 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.0 02 Jul-08
5    ---------------------
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
18    Version 7.7 07-May-08
19    ---------------------
21    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
22        a string to a long long, pretend we don't even have a long long." This is
23        done by checking for the strtoq, strtoll, and _strtoi64 functions.
25    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
26        pre-7.6 versions, which defined a global no_arg variable instead of putting
27        it in the RE class. (See also #8 below.)
29    3.  Remove a line of dead code, identified by coverity and reported by Nuno
30        Lopes.
32    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
34        (1) The include/exclude patterns were being applied to the whole pathnames
35            of files, instead of just to the final components.
37        (2) If there was more than one level of directory, the subdirectories were
38            skipped unless they satisfied the include/exclude conditions. This is
39            inconsistent with GNU grep (and could even be seen as contrary to the
40            pcregrep specification - which I improved to make it absolutely clear).
41            The action now is always to scan all levels of directory, and just
42            apply the include/exclude patterns to regular files.
44    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
45        --exclude_dir in the tests to avoid scanning .svn directories.
47    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
48        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
49        doesn't support NULs in patterns.
51    7.  Added some missing "const"s to declarations of static tables in
52        pcre_compile.c and pcre_dfa_exec.c.
54    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
55        caused by fix #2  above. (Subsequently also a second patch to fix the
56        first patch. And a third patch - this was a messy problem.)
58    9.  Applied Craig's patch to remove the use of push_back().
60    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
61        matching function regexec().
63    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
64        which, however, unlike Perl's \g{...}, are subroutine calls, not back
65        references. PCRE supports relative numbers with this syntax (I don't think
66        Oniguruma does).
68    12. Previously, a group with a zero repeat such as (...){0} was completely
69        omitted from the compiled regex. However, this means that if the group
70        was called as a subroutine from elsewhere in the pattern, things went wrong
71        (an internal error was given). Such groups are now left in the compiled
72        pattern, with a new opcode that causes them to be skipped at execution
73        time.
75    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
76        to the way PCRE behaves:
78        (a) A lone ] character is dis-allowed (Perl treats it as data).
80        (b) A back reference to an unmatched subpattern matches an empty string
81            (Perl fails the current match path).
83        (c) A data ] in a character class must be notated as \] because if the
84            first data character in a class is ], it defines an empty class. (In
85            Perl it is not possible to have an empty class.) The empty class []
86            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
87            The negative empty class [^] matches any one character, independently
88            of the DOTALL setting.
90    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
91        non-existent subpattern following a character class starting with ']' and
92        containing () gave an internal compiling error instead of "reference to
93        non-existent subpattern". Fortunately, when the pattern did exist, the
94        compiled code was correct. (When scanning forwards to check for the
95        existencd of the subpattern, it was treating the data ']' as terminating
96        the class, so got the count wrong. When actually compiling, the reference
97        was subsequently set up correctly.)
99    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
100        it was being rejected as not supported by pcre_dfa_exec(), even though
101        other assertions are supported. I have made pcre_dfa_exec() support
102        (*FAIL).
104    16. The implementation of 13c above involved the invention of a new opcode,
105        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
106        cannot be changed at match time, I realized I could make a small
107        improvement to matching performance by compiling OP_ALLANY instead of
108        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
109        on the OP_ANY path.
111    17. Compiling pcretest on Windows with readline support failed without the
112        following two fixes: (1) Make the unistd.h include conditional on
113        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
115    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
116        ncurses library to be included for pcretest when ReadLine support is
117        requested, but also to allow for it to be overridden. This patch came from
118        Daniel Bergström.
120    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
121        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
122        any errors with the current Unicode tables. Thanks to Peter Kankowski for
123        spotting this.
126    Version 7.6 28-Jan-08
127    ---------------------
129    1.  A character class containing a very large number of characters with
130        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
131        overflow.
133    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
134        HAVE_LONG_LONG is not defined.
136    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
137        bring them up to date and include new features. This patch includes:
139        - Fixed PH's badly added libz and libbz2 support.
140        - Fixed a problem with static linking.
141        - Added pcredemo. [But later removed - see 7 below.]
142        - Fixed dftables problem and added an option.
143        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
144            HAVE_LONG_LONG.
145        - Added readline support for pcretest.
146        - Added an listing of the option settings after cmake has run.
148    4.  A user submitted a patch to Makefile that makes it easy to create
149        "pcre.dll" under mingw when using Configure/Make. I added stuff to
150        Makefile.am that cause it to include this special target, without
151        affecting anything else. Note that the same mingw target plus all
152        the other distribution libraries and programs are now supported
153        when configuring with CMake (see 6 below) instead of with
154        Configure/Make.
156    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
157        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
158        exported in the Windows port". It has not yet been confirmed that the patch
159        solves the problem, but it does no harm.
161    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
162        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
163        with CMake, and also correct the comment about stack recursion.
165    7.  Remove the automatic building of pcredemo from the ./configure system and
166        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
167        of a program that users should build themselves after PCRE is installed, so
168        building it automatically is not really right. What is more, it gave
169        trouble in some build environments.
171    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
174    Version 7.5 10-Jan-08
175    ---------------------
177    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
178        values in parens when parsing an RE using the C++ wrapper."
180    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
181        Characters greater than 255 were excluded from the class instead of being
182        included.
184    3.  The same bug as (2) above applied to negated POSIX classes such as
185        [:^space:].
187    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
188        defined or documented. It seems to have been a typo for PCRE_STATIC, so
189        I have changed it.
191    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
192        first named subpattern) and a construct such as (?&a) would reference the
193        first named subpattern whose name started with "a" (in other words, the
194        length check was missing). Both these problems are fixed. "Subpattern name
195        expected" is now given for (?&) (a zero-length name), and this patch also
196        makes it give the same error for \k'' (previously it complained that that
197        was a reference to a non-existent subpattern).
199    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
200        this is right because (?- can be followed by option settings as well as by
201        digits. I have, however, made the messages clearer.
203    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
204        than the number used in the conditional) now cause a compile-time error.
205        This is actually not compatible with Perl, which accepts such patterns, but
206        treats the conditional as always being FALSE (as PCRE used to), but it
207        seems to me that giving a diagnostic is better.
209    8.  Change "alphameric" to the more common word "alphanumeric" in comments
210        and messages.
212    9.  Fix two occurrences of "backslash" in comments that should have been
213        "backspace".
215    10. Remove two redundant lines of code that can never be obeyed (their function
216        was moved elsewhere).
218    11. The program that makes PCRE's Unicode character property table had a bug
219        which caused it to generate incorrect table entries for sequences of
220        characters that have the same character type, but are in different scripts.
221        It amalgamated them into a single range, with the script of the first of
222        them. In other words, some characters were in the wrong script. There were
223        thirteen such cases, affecting characters in the following ranges:
225          U+002b0 - U+002c1
226          U+0060c - U+0060d
227          U+0061e - U+00612
228          U+0064b - U+0065e
229          U+0074d - U+0076d
230          U+01800 - U+01805
231          U+01d00 - U+01d77
232          U+01d9b - U+01dbf
233          U+0200b - U+0200f
234          U+030fc - U+030fe
235          U+03260 - U+0327f
236          U+0fb46 - U+0fbb1
237          U+10450 - U+1049d
239    12. The -o option (show only the matching part of a line) for pcregrep was not
240        compatible with GNU grep in that, if there was more than one match in a
241        line, it showed only the first of them. It now behaves in the same way as
242        GNU grep.
244    13. If the -o and -v options were combined for pcregrep, it printed a blank
245        line for every non-matching line. GNU grep prints nothing, and pcregrep now
246        does the same. The return code can be used to tell if there were any
247        non-matching lines.
249    14. Added --file-offsets and --line-offsets to pcregrep.
251    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
252        infinitely looping recursion. The bug was that positive lookaheads were not
253        being skipped when checking for a possible empty match (negative lookaheads
254        and both kinds of lookbehind were skipped).
256    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
257        inclusion of <windows.h> to before rather than after the definition of
258        INVALID_FILE_ATTRIBUTES (patch from David Byron).
260    17. Specifying a possessive quantifier with a specific limit for a Unicode
261        character property caused pcre_compile() to compile bad code, which led at
262        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
263        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
264        caused the error; without that there was no problem.
266    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
268    19. Added --enable-pcretest-libreadline.
270    20. In pcrecpp.cc, the variable 'count' was incremented twice in
271        RE::GlobalReplace(). As a result, the number of replacements returned was
272        double what it should be. I removed one of the increments, but Craig sent a
273        later patch that removed the other one (the right fix) and added unit tests
274        that check the return values (which was not done before).
276    21. Several CMake things:
278        (1) Arranged that, when cmake is used on Unix, the libraries end up with
279            the names libpcre and libpcreposix, not just pcre and pcreposix.
281        (2) The above change means that pcretest and pcregrep are now correctly
282            linked with the newly-built libraries, not previously installed ones.
286    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
287        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
288        UTF-8 newline character). The key issue is that the pattern starts .*;
289        this means that the match must be either at the beginning, or after a
290        newline. The bug was in the code for advancing after a failed match and
291        checking that the new position followed a newline. It was not taking
292        account of UTF-8 characters correctly.
294    23. PCRE was behaving differently from Perl in the way it recognized POSIX
295        character classes. PCRE was not treating the sequence [:...:] as a
296        character class unless the ... were all letters. Perl, however, seems to
297        allow any characters between [: and :], though of course it rejects as
298        unknown any "names" that contain non-letters, because all the known class
299        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
300        for example, whereas PCRE did not - it did not recognize a POSIX character
301        class. This seemed a bit dangerous, so the code has been changed to be
302        closer to Perl. The behaviour is not identical to Perl, because PCRE will
303        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
304        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
305        Perl does, and where it didn't before.
307    24. Rewrite so as to remove the single use of %n from pcregrep because in some
308        Windows environments %n is disabled by default.
311    Version 7.4 21-Sep-07
312    ---------------------
314    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
315        means that a class such as [\s] counted as "explicit reference to CR or
316        LF". That isn't really right - the whole point of the change was to try to
317        help when there was an actual mention of one of the two characters. So now
318        the change happens only if \r or \n (or a literal CR or LF) character is
319        encountered.
321    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
322        of both had grown to the point where there were only 3 bits left.
323        Fortunately, there was spare space in the data structure, and so I have
324        moved the internal flags into a new 16-bit field to free up more option
325        bits.
327    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
328        but did not set the internal JCHANGED flag - either of these is enough to
329        control the way the "get" function works - but the PCRE_INFO_JCHANGED
330        facility is supposed to tell if (?J) was ever used, so now (?J) at the
331        start sets both bits.
333    4.  Added options (at build time, compile time, exec time) to change \R from
334        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
336    5.  doc/pcresyntax.html was missing from the distribution.
338    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
339        compatibility, even though it is no longer used.
341    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
342        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
343        windows.h file is present (where different names are used). [This was
344        reversed later after testing - see 16 below.]
346    8.  Changed all #include <config.h> to #include "config.h". There were also
347        some further <pcre.h> cases that I changed to "pcre.h".
349    9.  When pcregrep was used with the --colour option, it missed the line ending
350        sequence off the lines that it output.
352    10. It was pointed out to me that arrays of string pointers cause lots of
353        relocations when a shared library is dynamically loaded. A technique of
354        using a single long string with a table of offsets can drastically reduce
355        these. I have refactored PCRE in four places to do this. The result is
356        dramatic:
358          Originally:                          290
359          After changing UCP table:            187
360          After changing error message table:   43
361          After changing table of "verbs"       36
362          After changing table of Posix names   22
364        Thanks to the folks working on Gregex for glib for this insight.
366    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
367        unicode-properties was also set.
369    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
371    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
372        checked only for CRLF.
374    14. Added casts to pcretest.c to avoid compiler warnings.
376    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
378    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
379        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
380        entirely. This removes changes made in 7 above.
382    17. The CMake files have been updated, and there is now more information about
383        building with CMake in the NON-UNIX-USE document.
386    Version 7.3 28-Aug-07
387    ---------------------
389     1. In the rejigging of the build system that eventually resulted in 7.1, the
390        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
391        brackets there is not right, since it causes compilers to look for an
392        installed pcre.h, not the version that is in the source that is being
393        compiled (which of course may be different). I have changed it back to:
395          #include "pcre.h"
397        I have a vague recollection that the change was concerned with compiling in
398        different directories, but in the new build system, that is taken care of
399        by the VPATH setting the Makefile.
401     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
402        when the subject happened to end in the byte 0x85 (e.g. if the last
403        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
404        characters but of course it shouldn't be taken as a newline when it is part
405        of another character. The bug was that, for an unlimited repeat of . in
406        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
407        characters when looking for a newline.
409     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
411     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
412        in debug output.
414     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
415        long printing in the pcrecpp unittest when running under MinGW.
417     6. ESC_K was left out of the EBCDIC table.
419     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
420        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
421        limit also applies to "virtual nesting" when a pattern is recursive, and in
422        this case 1000 isn't so big. I have been able to remove this limit at the
423        expense of backing off one optimization in certain circumstances. Normally,
424        when pcre_exec() would call its internal match() function recursively and
425        immediately return the result unconditionally, it uses a "tail recursion"
426        feature to save stack. However, when a subpattern that can match an empty
427        string has an unlimited repetition quantifier, it no longer makes this
428        optimization. That gives it a stack frame in which to save the data for
429        checking that an empty string has been matched. Previously this was taken
430        from the 1000-entry workspace that had been reserved. So now there is no
431        explicit limit, but more stack is used.
433     8. Applied Daniel's patches to solve problems with the import/export magic
434        syntax that is required for Windows, and which was going wrong for the
435        pcreposix and pcrecpp parts of the library. These were overlooked when this
436        problem was solved for the main library.
438     9. There were some crude static tests to avoid integer overflow when computing
439        the size of patterns that contain repeated groups with explicit upper
440        limits. As the maximum quantifier is 65535, the maximum group length was
441        set at 30,000 so that the product of these two numbers did not overflow a
442        32-bit integer. However, it turns out that people want to use groups that
443        are longer than 30,000 bytes (though not repeat them that many times).
444        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
445        made it possible to implement the integer overflow checks in a much more
446        dynamic way, which I have now done. The artificial limitation on group
447        length has been removed - we now have only the limit on the total length of
448        the compiled pattern, which depends on the LINK_SIZE setting.
450    10. Fixed a bug in the documentation for get/copy named substring when
451        duplicate names are permitted. If none of the named substrings are set, the
452        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
453        empty string.
455    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
456        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
457        because the ] is interpreted as the first data character and the
458        terminating ] is not found. PCRE has been made compatible with Perl in this
459        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
460        cause memory overwriting.
462    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
463        string has been matched (to stop an infinite loop). It was not recognizing
464        a conditional subpattern that could match an empty string if that
465        subpattern was within another subpattern. For example, it looped when
466        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
467        condition was not nested. This bug has been fixed.
469    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
470        past the start of the subject in the presence of bytes with the top bit
471        set, for example "\x8aBCD".
473    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
474        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
476    14. Optimized (?!) to (*FAIL).
478    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
479        This restricts code points to be within the range 0 to 0x10FFFF, excluding
480        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
481        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
482        does: it's just the validity check that is more restrictive.
484    16. Inserted checks for integer overflows during escape sequence (backslash)
485        processing, and also fixed erroneous offset values for syntax errors during
486        backslash processing.
488    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
489        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
491    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
492        caused an overrun.
494    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
495        something other than just ASCII characters) inside a group that had an
496        unlimited repeat caused a loop at compile time (while checking to see
497        whether the group could match an empty string).
499    20. Debugging a pattern containing \p or \P could cause a crash. For example,
500        [\P{Any}] did so. (Error in the code for printing property names.)
502    21. An orphan \E inside a character class could cause a crash.
504    22. A repeated capturing bracket such as (A)? could cause a wild memory
505        reference during compilation.
507    23. There are several functions in pcre_compile() that scan along a compiled
508        expression for various reasons (e.g. to see if it's fixed length for look
509        behind). There were bugs in these functions when a repeated \p or \P was
510        present in the pattern. These operators have additional parameters compared
511        with \d, etc, and these were not being taken into account when moving along
512        the compiled data. Specifically:
514        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
515            length.
517        (b) An item such as \pL+ within a repeated group could cause crashes or
518            loops.
520        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
521            "reference to non-existent subpattern" error.
523        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
525    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
526        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
528    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
530    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
531        character were causing crashes (broken optimization).
533    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
534        \p or \P) caused a compile-time loop.
536    28. More problems have arisen in unanchored patterns when CRLF is a valid line
537        break. For example, the unstudied pattern [\r\n]A does not match the string
538        "\r\nA" because change 7.0/46 below moves the current point on by two
539        characters after failing to match at the start. However, the pattern \nA
540        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
541        the same is true. There doesn't seem any very clean way out of this, but
542        what I have chosen to do makes the common cases work: PCRE now takes note
543        of whether there can be an explicit match for \r or \n anywhere in the
544        pattern, and if so, 7.0/46 no longer applies. As part of this change,
545        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
546        pattern has explicit CR or LF references.
548    29. Added (*CR) etc for changing newline setting at start of pattern.
551    Version 7.2 19-Jun-07
552    ---------------------
554     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
555        which is apparently normally available under Windows.
557     2. Re-jig the pcregrep tests with different newline settings in an attempt
558        to make them independent of the local environment's newline setting.
560     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
562     4. Some of the "internals" tests were previously cut out when the link size
563        was not 2, because the output contained actual offsets. The recent new
564        "Z" feature of pcretest means that these can be cut out, making the tests
565        usable with all link sizes.
567     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
568        stack recursion. This gives a massive performance boost under BSD, but just
569        a small improvement under Linux. However, it saves one field in the frame
570        in all cases.
572     6. Added more features from the forthcoming Perl 5.10:
574        (a) (?-n) (where n is a string of digits) is a relative subroutine or
575            recursion call. It refers to the nth most recently opened parentheses.
577        (b) (?+n) is also a relative subroutine call; it refers to the nth next
578            to be opened parentheses.
580        (c) Conditions that refer to capturing parentheses can be specified
581            relatively, for example, (?(-2)... or (?(+3)...
583        (d) \K resets the start of the current match so that everything before
584            is not part of it.
586        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
588        (f) \g{name} is another synonym - part of Perl 5.10's unification of
589            reference syntax.
591        (g) (?| introduces a group in which the numbering of parentheses in each
592            alternative starts with the same number.
594        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
596     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
599     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
600        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
601        for detecting groups that can match an empty string.
603     9. A pattern with a very large number of alternatives (more than several
604        hundred) was running out of internal workspace during the pre-compile
605        phase, where pcre_compile() figures out how much memory will be needed. A
606        bit of new cunning has reduced the workspace needed for groups with
607        alternatives. The 1000-alternative test pattern now uses 12 bytes of
608        workspace instead of running out of the 4096 that are available.
610    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
612    11. Applied patch from Google to remove an optimization that didn't quite work.
613        The report of the bug said:
615          pcrecpp::RE("a*").FullMatch("aaa") matches, while
616          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
617          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
619    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
620        it matched the wrong number of bytes.
623    Version 7.1 24-Apr-07
624    ---------------------
626     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
627        that is more "standard", making use of automake and other Autotools. There
628        is some re-arrangement of the files and adjustment of comments consequent
629        on this.
631     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
632        for recursive directory scanning broke on some systems because the files
633        are not scanned in any specific order and on different systems the order
634        was different. A call to "sort" has been inserted into RunGrepTest for the
635        approprate test as a short-term fix. In the longer term there may be an
636        alternative.
638     3. I had an email from Eric Raymond about problems translating some of PCRE's
639        man pages to HTML (despite the fact that I distribute HTML pages, some
640        people do their own conversions for various reasons). The problems
641        concerned the use of low-level troff macros .br and .in. I have therefore
642        removed all such uses from the man pages (some were redundant, some could
643        be replaced by .nf/.fi pairs). The 132html script that I use to generate
644        HTML has been updated to handle .nf/.fi and to complain if it encounters
645        .br or .in.
647     4. Updated comments in configure.ac that get placed in config.h.in and also
648        arranged for config.h to be included in the distribution, with the name
649        config.h.generic, for the benefit of those who have to compile without
650        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
652     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
653        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
654        makevp.bat for the current PCRE, using the additional files
655        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
657     6. A Windows user reported a minor discrepancy with test 2, which turned out
658        to be caused by a trailing space on an input line that had got lost in his
659        copy. The trailing space was an accident, so I've just removed it.
661     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
662        that is needed.
664     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
665        as "const" (a) because they are and (b) because it helps the PHP
666        maintainers who have recently made a script to detect big data structures
667        in the php code that should be moved to the .rodata section. I remembered
668        to update Builducptable as well, so it won't revert if ucptable.h is ever
669        re-created.
671     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
672        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
673        order to be able to cut out the UTF-8 tables in the latter when UTF-8
674        support is not required. This saves 1.5-2K of code, which is important in
675        some applications.
677        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
678        so as not to refer to the tables, even though these functions will never be
679        called when UTF-8 support is disabled. Otherwise there are problems with a
680        shared library.
682    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
684        (a) It was defining its arguments as char * instead of void *.
686        (b) It was assuming that all moves were upwards in memory; this was true
687            a long time ago when I wrote it, but is no longer the case.
689        The emulated memove() is provided for those environments that have neither
690        memmove() nor bcopy(). I didn't think anyone used it these days, but that
691        is clearly not the case, as these two bugs were recently reported.
693    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
694        and Detrail to create the HTML documentation, the .txt form of the man
695        pages, and it removes trailing spaces from listed files. It also creates
696        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
697        case, it wraps all the #defines with #ifndefs. This script should be run
698        before "make dist".
700    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
701        with Unicode property support.
703        (a) For a maximizing quantifier, if the two different cases of the
704            character were of different lengths in their UTF-8 codings (there are
705            some cases like this - I found 11), and the matching function had to
706            back up over a mixture of the two cases, it incorrectly assumed they
707            were both the same length.
709        (b) When PCRE was configured to use the heap rather than the stack for
710            recursion during matching, it was not correctly preserving the data for
711            the other case of a UTF-8 character when checking ahead for a match
712            while processing a minimizing repeat. If the check also involved
713            matching a wide character, but failed, corruption could cause an
714            erroneous result when trying to check for a repeat of the original
715            character.
717    13. Some tidying changes to the testing mechanism:
719        (a) The RunTest script now detects the internal link size and whether there
720            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
721            values substituted by "configure". (The RunGrepTest script already did
722            this for UTF-8.) The configure.ac script no longer substitutes the
723            relevant variables.
725        (b) The debugging options /B and /D in pcretest show the compiled bytecode
726            with length and offset values. This means that the output is different
727            for different internal link sizes. Test 2 is skipped for link sizes
728            other than 2 because of this, bypassing the problem. Unfortunately,
729            there was also a test in test 3 (the locale tests) that used /B and
730            failed for link sizes other than 2. Rather than cut the whole test out,
731            I have added a new /Z option to pcretest that replaces the length and
732            offset values with spaces. This is now used to make test 3 independent
733            of link size. (Test 2 will be tidied up later.)
735    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
736        segmentation fault instead of returning the appropriate error message.
738    15. In multiline mode when the newline sequence was set to "any", the pattern
739        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
740        This doesn't seem right; it now treats the CRLF combination as the line
741        ending, and so does not match in that case. It's only a pattern such as ^$
742        that would hit this one: something like ^ABC$ would have failed after \r
743        and then tried again after \r\n.
745    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
746        in an attempt to make files that differ only in their line terminators
747        compare equal. This works on Linux.
749    17. Under certain error circumstances pcregrep might try to free random memory
750        as it exited. This is now fixed, thanks to valgrind.
752    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
753        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
754        was because its rules for how to advance for /g after matching an empty
755        string at the end of a line did not allow for this case. They now check for
756        it specially.
758    20. pcretest is supposed to handle patterns and data of any length, by
759        extending its buffers when necessary. It was getting this wrong when the
760        buffer for a data line had to be extended.
762    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
763        CRLF as a newline sequence.
765    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
766        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
767        I have nevertheless tidied it up.
769    23. Added some casts to kill warnings from HP-UX ia64 compiler.
771    24. Added a man page for pcre-config.
774    Version 7.0 19-Dec-06
775    ---------------------
777     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
778        moving to gcc 4.1.1.
780     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
781        sys/time.h, which is documented as needed for this function. It doesn't
782        seem to matter on Linux, but it showed up on some releases of OS X.
784     3. It seems that there are systems where bytes whose values are greater than
785        127 match isprint() in the "C" locale. The "C" locale should be the
786        default when a C program starts up. In most systems, only ASCII printing
787        characters match isprint(). This difference caused the output from pcretest
788        to vary, making some of the tests fail. I have changed pcretest so that:
790        (a) When it is outputting text in the compiled version of a pattern, bytes
791            other than 32-126 are always shown as hex escapes.
793        (b) When it is outputting text that is a matched part of a subject string,
794            it does the same, unless a different locale has been set for the match
795            (using the /L modifier). In this case, it uses isprint() to decide.
797     4. Fixed a major bug that caused incorrect computation of the amount of memory
798        required for a compiled pattern when options that changed within the
799        pattern affected the logic of the preliminary scan that determines the
800        length. The relevant options are -x, and -i in UTF-8 mode. The result was
801        that the computed length was too small. The symptoms of this bug were
802        either the PCRE error "internal error: code overflow" from pcre_compile(),
803        or a glibc crash with a message such as "pcretest: free(): invalid next
804        size (fast)". Examples of patterns that provoked this bug (shown in
805        pcretest format) are:
807          /(?-x: )/x
808          /(?x)(?-x: \s*#\s*)/
809          /((?i)[\x{c0}])/8
810          /(?i:[\x{c0}])/8
812        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
813        is now done differently.
815     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
816        wrapper classes; (b) implement a new function in the C++ scanner that is
817        more efficient than the old way of doing things because it avoids levels of
818        recursion in the regex matching; (c) add a paragraph to the documentation
819        for the FullMatch() function.
821     6. The escape sequence \n was being treated as whatever was defined as
822        "newline". Not only was this contrary to the documentation, which states
823        that \n is character 10 (hex 0A), but it also went horribly wrong when
824        "newline" was defined as CRLF. This has been fixed.
826     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
827        was being set to -1 for the "end of line" case (supposedly a value that no
828        character can have). Though this value is never used (the check for end of
829        line is "zero bytes in current character"), it caused compiler complaints.
830        I've changed it to 0xffffffff.
832     8. In pcre_version.c, the version string was being built by a sequence of
833        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
834        string (as it is for production releases) called a macro with an empty
835        argument. The C standard says the result of this is undefined. The gcc
836        compiler treats it as an empty string (which was what was wanted) but it is
837        reported that Visual C gives an error. The source has been hacked around to
838        avoid this problem.
840     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
841        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
842        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
843        of them did).
845    10. Originally, pcretest opened its input and output without "b"; then I was
846        told that "b" was needed in some environments, so it was added for release
847        5.0 to both the input and output. (It makes no difference on Unix-like
848        systems.) Later I was told that it is wrong for the input on Windows. I've
849        now abstracted the modes into two macros, to make it easier to fiddle with
850        them, and removed "b" from the input mode under Windows.
852    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
854    12. Added -help and --help to pcretest as an official way of being reminded
855        of the options.
857    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
858        and pcrecpp.cc because they annoy compilers at high warning levels.
860    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
862    15. Fixed an occurrence of == in configure.ac that should have been = (shell
863        scripts are not C programs :-) and which was not noticed because it works
864        on Linux.
866    16. pcretest is supposed to handle any length of pattern and data line (as one
867        line or as a continued sequence of lines) by extending its input buffer if
868        necessary. This feature was broken for very long pattern lines, leading to
869        a string of junk being passed to pcre_compile() if the pattern was longer
870        than about 50K.
872    17. I have done a major re-factoring of the way pcre_compile() computes the
873        amount of memory needed for a compiled pattern. Previously, there was code
874        that made a preliminary scan of the pattern in order to do this. That was
875        OK when PCRE was new, but as the facilities have expanded, it has become
876        harder and harder to keep it in step with the real compile phase, and there
877        have been a number of bugs (see for example, 4 above). I have now found a
878        cunning way of running the real compile function in a "fake" mode that
879        enables it to compute how much memory it would need, while actually only
880        ever using a few hundred bytes of working memory and without too many
881        tests of the mode. This should make future maintenance and development
882        easier. A side effect of this work is that the limit of 200 on the nesting
883        depth of parentheses has been removed (though this was never a serious
884        limitation, I suspect). However, there is a downside: pcre_compile() now
885        runs more slowly than before (30% or more, depending on the pattern). I
886        hope this isn't a big issue. There is no effect on runtime performance.
888    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
889        newline (only possible for the last line of a file) and it was a
890        pattern that set a locale (followed by /Lsomething), pcretest crashed.
892    19. Added additional timing features to pcretest. (1) The -tm option now times
893        matching only, not compiling. (2) Both -t and -tm can be followed, as a
894        separate command line item, by a number that specifies the number of
895        repeats to use when timing. The default is 50000; this gives better
896        precision, but takes uncomfortably long for very large patterns.
898    20. Extended pcre_study() to be more clever in cases where a branch of a
899        subpattern has no definite first character. For example, (a*|b*)[cd] would
900        previously give no result from pcre_study(). Now it recognizes that the
901        first character must be a, b, c, or d.
903    21. There was an incorrect error "recursive call could loop indefinitely" if
904        a subpattern (or the entire pattern) that was being tested for matching an
905        empty string contained only one non-empty item after a nested subpattern.
906        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
907        incorrectly, because the \d was being skipped in the check.
909    22. The pcretest program now has a new pattern option /B and a command line
910        option -b, which is equivalent to adding /B to every pattern. This causes
911        it to show the compiled bytecode, without the additional information that
912        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
913        is the same as /B/I).
915    23. A new optimization is now able automatically to treat some sequences such
916        as a*b as a*+b. More specifically, if something simple (such as a character
917        or a simple class like \d) has an unlimited quantifier, and is followed by
918        something that cannot possibly match the quantified thing, the quantifier
919        is automatically "possessified".
921    24. A recursive reference to a subpattern whose number was greater than 39
922        went wrong under certain circumstances in UTF-8 mode. This bug could also
923        have affected the operation of pcre_study().
925    25. Realized that a little bit of performance could be had by replacing
926        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
928    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
930    27. Possessive quantifiers such as a++ were previously implemented by turning
931        them into atomic groups such as ($>a+). Now they have their own opcodes,
932        which improves performance. This includes the automatically created ones
933        from 23 above.
935    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
936        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
937        the first matched character to be a colon. This applied both to named and
938        numbered groups.
940    29. The ucpinternal.h header file was missing its idempotency #ifdef.
942    30. I was sent a "project" file called libpcre.a.dev which I understand makes
943        building PCRE on Windows easier, so I have included it in the distribution.
945    31. There is now a check in pcretest against a ridiculously large number being
946        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
947        loop, the loop is abandoned.
949    32. Forward references to subpatterns in conditions such as (?(2)...) where
950        subpattern 2 is defined later cause pcre_compile() to search forwards in
951        the pattern for the relevant set of parentheses. This search went wrong
952        when there were unescaped parentheses in a character class, parentheses
953        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
955    33. "Subroutine" calls and backreferences were previously restricted to
956        referencing subpatterns earlier in the regex. This restriction has now
957        been removed.
959    34. Added a number of extra features that are going to be in Perl 5.10. On the
960        whole, these are just syntactic alternatives for features that PCRE had
961        previously implemented using the Python syntax or my own invention. The
962        other formats are all retained for compatibility.
964        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
965            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
966            also .NET compatible.
968        (b) A recursion or subroutine call to a named group can now be defined as
969            (?&name) as well as (?P>name).
971        (c) A backreference to a named group can now be defined as \k<name> or
972            \k'name' as well as (?P=name). The new forms, as well as being in Perl
973            5.10, are also .NET compatible.
975        (d) A conditional reference to a named group can now use the syntax
976            (?(<name>) or (?('name') as well as (?(name).
978        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
979            groups (named and numbered) that are never evaluated inline, but can be
980            called as "subroutines" from elsewhere. In effect, the DEFINE condition
981            is always false. There may be only one alternative in such a group.
983        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
984            as the simple (?(R). The condition is true only if the most recent
985            recursion is that of the given number or name. It does not search out
986            through the entire recursion stack.
988        (g) The escape \gN or \g{N} has been added, where N is a positive or
989            negative number, specifying an absolute or relative reference.
991    35. Tidied to get rid of some further signed/unsigned compiler warnings and
992        some "unreachable code" warnings.
994    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
995        things, this adds five new scripts.
997    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
998        There were also incompatibilities regarding the handling of \Q..\E inside
999        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1000        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1002    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1003        matches an empty string, and forcibly breaks the loop. There were bugs in
1004        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1005        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1006        separate and independent bugs (that affected different cases) have been
1007        fixed.
1009    39. Refactored the code to abolish the use of different opcodes for small
1010        capturing bracket numbers. This is a tidy that I avoided doing when I
1011        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1012        The new approach is not only tidier, it makes it possible to reduce the
1013        memory needed to fix the previous bug (38).
1015    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1016        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1017        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1018        mode.
1020    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1021        report.
1023    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1024        copy construction and assignment in the C++ wrapper.
1026    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1027        couple of bugs that could have given wrong results in the "--newline=crlf"
1028        case.
1030    44. Added a number of casts and did some reorganization of signed/unsigned int
1031        variables following suggestions from Dair Grant. Also renamed the variable
1032        "this" as "item" because it is a C++ keyword.
1034    45. Arranged for dftables to add
1036          #include "pcre_internal.h"
1038        to pcre_chartables.c because without it, gcc 4.x may remove the array
1039        definition from the final binary if PCRE is built into a static library and
1040        dead code stripping is activated.
1042    46. For an unanchored pattern, if a match attempt fails at the start of a
1043        newline sequence, and the newline setting is CRLF or ANY, and the next two
1044        characters are CRLF, advance by two characters instead of one.
1047    Version 6.7 04-Jul-06
1048    ---------------------
1050     1. In order to handle tests when input lines are enormously long, pcretest has
1051        been re-factored so that it automatically extends its buffers when
1052        necessary. The code is crude, but this _is_ just a test program. The
1053        default size has been increased from 32K to 50K.
1055     2. The code in pcre_study() was using the value of the re argument before
1056        testing it for NULL. (Of course, in any sensible call of the function, it
1057        won't be NULL.)
1059     3. The memmove() emulation function in pcre_internal.h, which is used on
1060        systems that lack both memmove() and bcopy() - that is, hardly ever -
1061        was missing a "static" storage class specifier.
1063     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1064        containing an extended class (one that cannot be represented by a bitmap
1065        because it contains high-valued characters or Unicode property items, e.g.
1066        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1067        pattern, but PCRE should not loop if you do not (it no longer does).
1068        [Detail: two cases were found: (a) a repeated subpattern containing an
1069        extended class; (b) a recursive reference to a subpattern that followed a
1070        previous extended class. It wasn't skipping over the extended class
1071        correctly when UTF-8 mode was not set.]
1073     5. A negated single-character class was not being recognized as fixed-length
1074        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1075        compile error "lookbehind assertion is not fixed length".
1077     6. The RunPerlTest auxiliary script was showing an unexpected difference
1078        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1079        write a Perl script that can interpret lines of an input file either as
1080        byte characters or as UTF-8, which is what "perltest" was being required to
1081        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1082        can't do is switch easily at run time between having the "use utf8;" pragma
1083        or not. In the end, I fudged it by using the RunPerlTest script to insert
1084        "use utf8;" explicitly for the UTF-8 tests.
1086     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1087        the end of the subject string, contrary to the documentation and to what
1088        Perl does. This was true of both matching functions. Now it matches only at
1089        the start of the subject and immediately after *internal* newlines.
1091     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1092        a pointer to an int instead of a pointer to an unsigned long int. This
1093        caused problems on 64-bit systems.
1095     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1096        instance of the 'standard' template library not being so standard".
1098    10. There was no check on the number of named subpatterns nor the maximum
1099        length of a subpattern name. The product of these values is used to compute
1100        the size of the memory block for a compiled pattern. By supplying a very
1101        long subpattern name and a large number of named subpatterns, the size
1102        computation could be caused to overflow. This is now prevented by limiting
1103        the length of names to 32 characters, and the number of named subpatterns
1104        to 10,000.
1106    11. Subpatterns that are repeated with specific counts have to be replicated in
1107        the compiled pattern. The size of memory for this was computed from the
1108        length of the subpattern and the repeat count. The latter is limited to
1109        65535, but there was no limit on the former, meaning that integer overflow
1110        could in principle occur. The compiled length of a repeated subpattern is
1111        now limited to 30,000 bytes in order to prevent this.
1113    12. Added the optional facility to have named substrings with the same name.
1115    13. Added the ability to use a named substring as a condition, using the
1116        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1117        are numbers (not recommended). Forward references are permitted.
1119    14. Added forward references in named backreferences (if you see what I mean).
1121    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1122        pattern could run off the end of the subject. For example, the pattern
1123        "(?s)(.{1,5})"8 did this with the subject "ab".
1125    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1126        PCRE_CASELESS was set when matching characters that were quantified with ?
1127        or *.
1129    17. A character class other than a single negated character that had a minimum
1130        but no maximum quantifier - for example [ab]{6,} - was not handled
1131        correctly by pce_dfa_exec(). It would match only one character.
1133    18. A valid (though odd) pattern that looked like a POSIX character
1134        class but used an invalid character after [ (for example [[,abc,]]) caused
1135        pcre_compile() to give the error "Failed: internal error: code overflow" or
1136        in some cases to crash with a glibc free() error. This could even happen if
1137        the pattern terminated after [[ but there just happened to be a sequence of
1138        letters, a binary zero, and a closing ] in the memory that followed.
1140    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1141        over the years. Originally (before any Unicode support), just the bottom 8
1142        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1143        output from "man perlunicode" includes this:
1145          The regular expression compiler produces polymorphic opcodes.  That
1146          is, the pattern adapts to the data and automatically switches to
1147          the Unicode character scheme when presented with Unicode data--or
1148          instead uses a traditional byte scheme when presented with byte
1149          data.
1151        Sadly, a wide octal escape does not cause a switch, and in a string with
1152        no other multibyte characters, these octal escapes are treated as before.
1153        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1154        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1155        Unicode string.
1157        I have not perpetrated such confusion in PCRE. Up till now, it took just
1158        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1159        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1160        translate to the appropriate multibyte character.
1162    29. Applied some refactoring to reduce the number of warnings from Microsoft
1163        and Borland compilers. This has included removing the fudge introduced
1164        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1165        a warning about an unused variable.
1167    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1168        characters since release 4.0, because Perl (from release 5.004) does not.
1169        [Or at least, is documented not to: some releases seem to be in conflict
1170        with the documentation.] However, when a pattern was studied with
1171        pcre_study() and all its branches started with \s, PCRE still included VT
1172        as a possible starting character. Of course, this did no harm; it just
1173        caused an unnecessary match attempt.
1175    22. Removed a now-redundant internal flag bit that recorded the fact that case
1176        dependency changed within the pattern. This was once needed for "required
1177        byte" processing, but is no longer used. This recovers a now-scarce options
1178        bit. Also moved the least significant internal flag bit to the most-
1179        significant bit of the word, which was not previously used (hangover from
1180        the days when it was an int rather than a uint) to free up another bit for
1181        the future.
1183    23. Added support for CRLF line endings as well as CR and LF. As well as the
1184        default being selectable at build time, it can now be changed at runtime
1185        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1186        specify that it is scanning data with non-default line endings.
1188    24. Changed the definition of CXXLINK to make it agree with the definition of
1189        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1191    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1192        recursions. This makes a big different to stack usage for some patterns.
1194    26. If a subpattern containing a named recursion or subroutine reference such
1195        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1196        the space required for the compiled pattern went wrong and gave too small a
1197        value. Depending on the environment, this could lead to "Failed: internal
1198        error: code overflow at offset 49" or "glibc detected double free or
1199        corruption" errors.
1201    27. Applied patches from Google (a) to support the new newline modes and (b) to
1202        advance over multibyte UTF-8 characters in GlobalReplace.
1204    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1205        difference for some implementation of PCRE in some Windows version.
1207    29. Added some extra testing facilities to pcretest:
1209        \q<number>   in a data line sets the "match limit" value
1210        \Q<number>   in a data line sets the "match recursion limt" value
1211        -S <number>  sets the stack size, where <number> is in megabytes
1213        The -S option isn't available for Windows.
1216    Version 6.6 06-Feb-06
1217    ---------------------
1219     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1220        in pcreposix.h. I have copied the definition from pcre.h.
1222     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1223        because pcre.h is no longer a built file.
1225     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1226        not normally included in the compiled code.
1229    Version 6.5 01-Feb-06
1230    ---------------------
1232     1. When using the partial match feature with pcre_dfa_exec(), it was not
1233        anchoring the second and subsequent partial matches at the new starting
1234        point. This could lead to incorrect results. For example, with the pattern
1235        /1234/, partially matching against "123" and then "a4" gave a match.
1237     2. Changes to pcregrep:
1239        (a) All non-match returns from pcre_exec() were being treated as failures
1240            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1241            error message is output. Some extra information is given for the
1242            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1243            probably the only errors that are likely to be caused by users (by
1244            specifying a regex that has nested indefinite repeats, for instance).
1245            If there are more than 20 of these errors, pcregrep is abandoned.
1247        (b) A binary zero was treated as data while matching, but terminated the
1248            output line if it was written out. This has been fixed: binary zeroes
1249            are now no different to any other data bytes.
1251        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1252            used to set a locale for matching. The --locale=xxxx long option has
1253            been added (no short equivalent) to specify a locale explicitly on the
1254            pcregrep command, overriding the environment variables.
1256        (d) When -B was used with -n, some line numbers in the output were one less
1257            than they should have been.
1259        (e) Added the -o (--only-matching) option.
1261        (f) If -A or -C was used with -c (count only), some lines of context were
1262            accidentally printed for the final match.
1264        (g) Added the -H (--with-filename) option.
1266        (h) The combination of options -rh failed to suppress file names for files
1267            that were found from directory arguments.
1269        (i) Added the -D (--devices) and -d (--directories) options.
1271        (j) Added the -F (--fixed-strings) option.
1273        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1275        (l) Added the --colo(u)r option.
1277        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1278            is not present by default.
1280     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1281        items such as (?R) or (?1), when the recursion could match a number of
1282        alternatives. If it matched one of the alternatives, but subsequently,
1283        outside the recursion, there was a failure, the code tried to back up into
1284        the recursion. However, because of the way PCRE is implemented, this is not
1285        possible, and the result was an incorrect result from the match.
1287        In order to prevent this happening, the specification of recursion has
1288        been changed so that all such subpatterns are automatically treated as
1289        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1291     4. I had overlooked the fact that, in some locales, there are characters for
1292        which isalpha() is true but neither isupper() nor islower() are true. In
1293        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1294        and ordfeminine) are like this. This affected the treatment of \w and \W
1295        when they appeared in character classes, but not when they appeared outside
1296        a character class. The bit map for "word" characters is now created
1297        separately from the results of isalnum() instead of just taking it from the
1298        upper, lower, and digit maps. (Plus the underscore character, of course.)
1300     5. The above bug also affected the handling of POSIX character classes such as
1301        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1302        permanent tables. Instead, the bit maps for such a class were previously
1303        created as the appropriate unions of the upper, lower, and digit bitmaps.
1304        Now they are created by subtraction from the [[:word:]] class, which has
1305        its own bitmap.
1307     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1308        It is created by subtracting the vertical space characters (\x09, \x0a,
1309        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1310        subtraction was done in the overall bitmap for a character class, meaning
1311        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1312        be recognized. This bug has been fixed.
1314     7. Patches from the folks at Google:
1316          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1317          real life, but is still worth protecting against".
1319          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1320          regular expressions".
1322          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1323          have it.
1325          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1326          "configure" and the latter not, in order to fix a problem somebody had
1327          with compiling the Arg class on HP-UX.
1329          (e) Improve the error-handling of the C++ wrapper a little bit.
1331          (f) New tests for checking recursion limiting.
1333     8. The pcre_memmove() function, which is used only if the environment does not
1334        have a standard memmove() function (and is therefore rarely compiled),
1335        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1336        returning a result (though PCRE never actually uses the result).
1338     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1339        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1340        returned instead of calling malloc() with an overflowing number that would
1341        most likely cause subsequent chaos.
1343    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1345    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1346        with this option is matched, the nmatch and pmatch options of regexec() are
1347        ignored.
1349    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1350        provided in case anyone wants to the the POSIX interface with UTF-8
1351        strings.
1353    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1354        C++ linking (needed for some HP-UX environments).
1356    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1357        (unused parameter) and in the pcre_printint() function (omitted "default"
1358        switch label when the default is to do nothing).
1360    15. Added some code to make it possible, when PCRE is compiled as a C++
1361        library, to replace subject pointers for pcre_exec() with a smart pointer
1362        class, thus making it possible to process discontinuous strings.
1364    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1365        much the same function. They were added by different people who were trying
1366        to make PCRE easy to compile on non-Unix systems. It has been suggested
1367        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1368        for compiling on Windows systems. I have therefore replaced it with
1369        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1370        defaults to "extern" for C or "extern C" for C++, which works fine on
1371        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1372        SCOPE with something explicit in config.h. In addition:
1374        (a) pcreposix.h still had just "extern" instead of either of these macros;
1375            I have replaced it with PCRE_DATA_SCOPE.
1377        (b) Functions such as _pcre_xclass(), which are internal to the library,
1378            but external in the C sense, all had PCRE_EXPORT in their definitions.
1379            This is apparently wrong for the Windows case, so I have removed it.
1380            (It makes no difference on Unix-like systems.)
1382    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1383        of recursive calls to match(). This is different to MATCH_LIMIT because
1384        that limits the total number of calls to match(), not all of which increase
1385        the depth of recursion. Limiting the recursion depth limits the amount of
1386        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1387        when PCRE is compiled, and changed at run time. A patch from Google adds
1388        this functionality to the C++ interface.
1390    18. Changes to the handling of Unicode character properties:
1392        (a) Updated the table to Unicode 4.1.0.
1394        (b) Recognize characters that are not in the table as "Cn" (undefined).
1396        (c) I revised the way the table is implemented to a much improved format
1397            which includes recognition of ranges. It now supports the ranges that
1398            are defined in UnicodeData.txt, and it also amalgamates other
1399            characters into ranges. This has reduced the number of entries in the
1400            table from around 16,000 to around 3,000, thus reducing its size
1401            considerably. I realized I did not need to use a tree structure after
1402            all - a binary chop search is just as efficient. Having reduced the
1403            number of entries, I extended their size from 6 bytes to 8 bytes to
1404            allow for more data.
1406        (d) Added support for Unicode script names via properties such as \p{Han}.
1408    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1409        matching that character.
1411    20. When matching a repeated Unicode property with a minimum greater than zero,
1412        (for example \pL{2,}), PCRE could look past the end of the subject if it
1413        reached it while seeking the minimum number of characters. This could
1414        happen only if some of the characters were more than one byte long, because
1415        there is a check for at least the minimum number of bytes.
1417    21. Refactored the implementation of \p and \P so as to be more general, to
1418        allow for more different types of property in future. This has changed the
1419        compiled form incompatibly. Anybody with saved compiled patterns that use
1420        \p or \P will have to recompile them.
1422    22. Added "Any" and "L&" to the supported property types.
1424    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1425        but give a compile time error if the value is greater than 0xff.
1427    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1428        accidentally not being installed or uninstalled.
1430    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1431        made were to insert the current release number. This seemed silly, because
1432        it made things harder for people building PCRE on systems that don't run
1433        "configure". I have turned pcre.h into a distributed file, no longer built
1434        by "configure", with the version identification directly included. There is
1435        no longer a pcre.h.in file.
1437        However, this change necessitated a change to the pcre-config script as
1438        well. It is built from pcre-config.in, and one of the substitutions was the
1439        release number. I have updated configure.ac so that ./configure now finds
1440        the release number by grepping pcre.h.
1442    26. Added the ability to run the tests under valgrind.
1445    Version 6.4 05-Sep-05
1446    ---------------------
1448     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1449        "--" to be printed when multiple files were scanned, even when none of the
1450        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1451        consider it to be a bug, and have restored the previous behaviour.
1453     2. A couple of code tidies to get rid of compiler warnings.
1455     3. The pcretest program used to cheat by referring to symbols in the library
1456        whose names begin with _pcre_. These are internal symbols that are not
1457        really supposed to be visible externally, and in some environments it is
1458        possible to suppress them. The cheating is now confined to including
1459        certain files from the library's source, which is a bit cleaner.
1461     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1462        file's purpose clearer.
1464     5. Reorganized pcre_ucp_findchar().
1467    Version 6.3 15-Aug-05
1468    ---------------------
1470     1. The file libpcre.pc.in did not have general read permission in the tarball.
1472     2. There were some problems when building without C++ support:
1474        (a) If C++ support was not built, "make install" and "make test" still
1475            tried to test it.
1477        (b) There were problems when the value of CXX was explicitly set. Some
1478            changes have been made to try to fix these, and ...
1480        (c) --disable-cpp can now be used to explicitly disable C++ support.
1482        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1483            backslash in a target when C++ was disabled. This confuses some
1484            versions of "make", apparently. Using an intermediate variable solves
1485            this. (Same for CPP_LOBJ.)
1487     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1488        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1489        necessary on certain architectures.
1491     4. Added a setting of -export-symbols-regex to the link command to remove
1492        those symbols that are exported in the C sense, but actually are local
1493        within the library, and not documented. Their names all begin with
1494        "_pcre_". This is not a perfect job, because (a) we have to except some
1495        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1496        available (and never for static libraries). I have made a note to try to
1497        find a way round (a) in the future.
1500    Version 6.2 01-Aug-05
1501    ---------------------
1503     1. There was no test for integer overflow of quantifier values. A construction
1504        such as {1111111111111111} would give undefined results. What is worse, if
1505        a minimum quantifier for a parenthesized subpattern overflowed and became
1506        negative, the calculation of the memory size went wrong. This could have
1507        led to memory overwriting.
1509     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1511     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1512        operating environments where this matters.
1514     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1515        PCRE options from within the C++ wrapper.
1517     5. Named capturing subpatterns were not being correctly counted when a pattern
1518        was compiled. This caused two problems: (a) If there were more than 100
1519        such subpatterns, the calculation of the memory needed for the whole
1520        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1521        back references of the form \12, where the number was greater than 9, were
1522        not recognized as back references, even though there were sufficient
1523        previous subpatterns.
1525     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1526        versions of gcc, e.g. 2.95.4.
1529    Version 6.1 21-Jun-05
1530    ---------------------
1532     1. There was one reference to the variable "posix" in pcretest.c that was not
1533        surrounded by "#if !defined NOPOSIX".
1535     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1536        the cross-check on the old pcre_info() function, for the benefit of the
1537        cut-down version of PCRE that is currently imported into Exim.
1539     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1540        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1541        patterns that start (?i) but I don't think that matters. The use of (?i) is
1542        just an example; this all applies to the other options as well.
1544     4. Since libtool seems to echo the compile commands it is issuing, the output
1545        from "make" can be reduced a bit by putting "@" in front of each libtool
1546        compile command.
1548     5. Patch from the folks at Google for configure.in to be a bit more thorough
1549        in checking for a suitable C++ installation before trying to compile the
1550        C++ stuff. This should fix a reported problem when a compiler was present,
1551        but no suitable headers.
1553     6. The man pages all had just "PCRE" as their title. I have changed them to
1554        be the relevant file name. I have also arranged that these names are
1555        retained in the file doc/pcre.txt, which is a concatenation in text format
1556        of all the man pages except the little individual ones for each function.
1558     7. The NON-UNIX-USE file had not been updated for the different set of source
1559        files that come with release 6. I also added a few comments about the C++
1560        wrapper.
1563    Version 6.0 07-Jun-05
1564    ---------------------
1566     1. Some minor internal re-organization to help with my DFA experiments.
1568     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1569        didn't matter for the library itself when fully configured, but did matter
1570        when compiling without UCP support, or within Exim, where the ucp files are
1571        not imported.
1573     3. Refactoring of the library code to split up the various functions into
1574        different source modules. The addition of the new DFA matching code (see
1575        below) to a single monolithic source would have made it really too
1576        unwieldy, quite apart from causing all the code to be include in a
1577        statically linked application, when only some functions are used. This is
1578        relevant even without the DFA addition now that patterns can be compiled in
1579        one application and matched in another.
1581        The downside of splitting up is that there have to be some external
1582        functions and data tables that are used internally in different modules of
1583        the library but which are not part of the API. These have all had their
1584        names changed to start with "_pcre_" so that they are unlikely to clash
1585        with other external names.
1587     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1588        a different (DFA) algorithm. Although it is slower than the original
1589        function, it does have some advantages for certain types of matching
1590        problem.
1592     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1593        including restarting after a partial match.
1595     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1596        defined when compiling for Windows was sent to me. I have put it into the
1597        code, though I have no means of testing or verifying it.
1599     7. Added the pcre_refcount() auxiliary function.
1601     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1602        match before or at the first newline in the subject string. In pcretest,
1603        the /f option on a pattern can be used to set this.
1605     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1606        would behave wrongly. This has been present in PCRE since release 4.0.
1608    10. A number of changes to the pcregrep command:
1610        (a) Refactored how -x works; insert ^(...)$ instead of setting
1611            PCRE_ANCHORED and checking the length, in preparation for adding
1612            something similar for -w.
1614        (b) Added the -w (match as a word) option.
1616        (c) Refactored the way lines are read and buffered so as to have more
1617            than one at a time available.
1619        (d) Implemented a pcregrep test script.
1621        (e) Added the -M (multiline match) option. This allows patterns to match
1622            over several lines of the subject. The buffering ensures that at least
1623            8K, or the rest of the document (whichever is the shorter) is available
1624            for matching (and similarly the previous 8K for lookbehind assertions).
1626        (f) Changed the --help output so that it now says
1628              -w, --word-regex(p)
1630            instead of two lines, one with "regex" and the other with "regexp"
1631            because that confused at least one person since the short forms are the
1632            same. (This required a bit of code, as the output is generated
1633            automatically from a table. It wasn't just a text change.)
1635        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1636            option but starts with a hyphen. Could be a pattern or a path name
1637            starting with a hyphen, for instance.
1639        (h) "-" can be given as a file name to represent stdin.
1641        (i) When file names are being printed, "(standard input)" is used for
1642            the standard input, for compatibility with GNU grep. Previously
1643            "<stdin>" was used.
1645        (j) The option --label=xxx can be used to supply a name to be used for
1646            stdin when file names are being printed. There is no short form.
1648        (k) Re-factored the options decoding logic because we are going to add
1649            two more options that take data. Such options can now be given in four
1650            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1652        (l) Added the -A, -B, and -C options for requesting that lines of context
1653            around matches be printed.
1655        (m) Added the -L option to print the names of files that do not contain
1656            any matching lines, that is, the complement of -l.
1658        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1659            continue to scan other files.
1661        (o) The -s option was incorrectly implemented. For compatibility with other
1662            greps, it now suppresses the error message for a non-existent or non-
1663            accessible file (but not the return code). There is a new option called
1664            -q that suppresses the output of matching lines, which was what -s was
1665            previously doing.
1667        (p) Added --include and --exclude options to specify files for inclusion
1668            and exclusion when recursing.
1670    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1671        Hopefully, it now does.
1673    12. Missing cast in pcre_study().
1675    13. Added an "uninstall" target to the makefile.
1677    14. Replaced "extern" in the function prototypes in Makefile.in with
1678        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1679        world, but is set differently for Windows.
1681    15. Added a second compiling function called pcre_compile2(). The only
1682        difference is that it has an extra argument, which is a pointer to an
1683        integer error code. When there is a compile-time failure, this is set
1684        non-zero, in addition to the error test pointer being set to point to an
1685        error message. The new argument may be NULL if no error number is required
1686        (but then you may as well call pcre_compile(), which is now just a
1687        wrapper). This facility is provided because some applications need a
1688        numeric error indication, but it has also enabled me to tidy up the way
1689        compile-time errors are handled in the POSIX wrapper.
1691    16. Added VPATH=.libs to the makefile; this should help when building with one
1692        prefix path and installing with another. (Or so I'm told by someone who
1693        knows more about this stuff than I do.)
1695    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1696        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1697        match everything, including newlines. This is not POSIX-compatible, but
1698        somebody wanted the feature. From pcretest it can be activated by using
1699        both the P and the s flags.
1701    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1703    19. libpcre.pc was being incorrectly installed as executable.
1705    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1706        it now also looks for '\r' so that it will work unmodified on Windows.
1708    21. Added Google's contributed C++ wrapper to the distribution.
1710    22. Added some untidy missing memory free() calls in pcretest, to keep
1711        Electric Fence happy when testing.
1715    Version 5.0 13-Sep-04
1716    ---------------------
1718     1. Internal change: literal characters are no longer packed up into items
1719        containing multiple characters in a single byte-string. Each character
1720        is now matched using a separate opcode. However, there may be more than one
1721        byte in the character in UTF-8 mode.
1723     2. The pcre_callout_block structure has two new fields: pattern_position and
1724        next_item_length. These contain the offset in the pattern to the next match
1725        item, and its length, respectively.
1727     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1728        insertion of callouts before each pattern item. Added the /C option to
1729        pcretest to make use of this.
1731     4. On the advice of a Windows user, the lines
1733          #if defined(_WIN32) || defined(WIN32)
1734          _setmode( _fileno( stdout ), 0x8000 );
1735          #endif  /* defined(_WIN32) || defined(WIN32) */
1737        have been added to the source of pcretest. This apparently does useful
1738        magic in relation to line terminators.
1740     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1741        for the benefit of those environments where the "b" makes a difference.
1743     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1744        to know about it. I have put a hack into configure.in that adds in code
1745        to set GCC=yes if CC=icc. This seems to end up at a point in the
1746        generated configure script that is early enough to affect the setting of
1747        compiler options, which is what is needed, but I have no means of testing
1748        whether it really works. (The user who reported this had patched the
1749        generated configure script, which of course I cannot do.)
1751        LATER: After change 22 below (new libtool files), the configure script
1752        seems to know about icc (and also ecc). Therefore, I have commented out
1753        this hack in configure.in.
1755     7. Added support for pkg-config (2 patches were sent in).
1757     8. Negated POSIX character classes that used a combination of internal tables
1758        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1759        [[:^ascii]]. Typically, they would match almost any characters. The other
1760        POSIX classes were not broken in this way.
1762     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1763        to find the match, as PCRE was deluded into thinking that the match had to
1764        start at the start point or following a newline. The same bug applied to
1765        patterns with negative forward assertions or any backward assertions
1766        preceding ".*" at the start, unless the pattern required a fixed first
1767        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1769    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1770        starting at the last subject character, bytes beyond the end of the subject
1771        string were read.
1773    11. Renamed the variable "class" as "classbits" to make life easier for C++
1774        users. (Previously there was a macro definition, but it apparently wasn't
1775        enough.)
1777    12. Added the new field "tables" to the extra data so that tables can be passed
1778        in at exec time, or the internal tables can be re-selected. This allows
1779        a compiled regex to be saved and re-used at a later time by a different
1780        program that might have everything at different addresses.
1782    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1783        -R library as well as a -L library.
1785    14. The debugging options of pcretest (-d on the command line or D on a
1786        pattern) showed incorrect output for anything following an extended class
1787        that contained multibyte characters and which was followed by a quantifier.
1789    15. Added optional support for general category Unicode character properties
1790        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1791        support. It adds about 90K to the size of the library. The meanings of the
1792        inbuilt class escapes such as \d and \s have NOT been changed.
1794    16. Updated pcredemo.c to include calls to free() to release the memory for the
1795        compiled pattern.
1797    17. The generated file chartables.c was being created in the source directory
1798        instead of in the building directory. This caused the build to fail if the
1799        source directory was different from the building directory, and was
1800        read-only.
1802    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1803        file. No doubt somebody will tell me if they don't make sense... Also added
1804        Dan Mooney's comments about building on OpenVMS.
1806    19. Added support for partial matching via the PCRE_PARTIAL option for
1807        pcre_exec() and the \P data escape in pcretest.
1809    20. Extended pcretest with 3 new pattern features:
1811        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1812              write the compiled pattern to the file whose name is "rest-of-line".
1813              This is a straight binary dump of the data, with the saved pointer to
1814              the character tables forced to be NULL. The study data, if any, is
1815              written too. After writing, pcretest reads a new pattern.
1817        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1818              compiled pattern from the given file. There must not be any
1819              occurrences of "<" in the file name (pretty unlikely); if there are,
1820              pcretest will instead treat the initial "<" as a pattern delimiter.
1821              After reading in the pattern, pcretest goes on to read data lines as
1822              usual.
1824        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1825              and 16-bit fields in a compiled pattern, to simulate a pattern that
1826              was compiled on a host of opposite endianness.
1828    21. The pcre-exec() function can now cope with patterns that were compiled on
1829        hosts of opposite endianness, with this restriction:
1831          As for any compiled expression that is saved and used later, the tables
1832          pointer field cannot be preserved; the extra_data field in the arguments
1833          to pcre_exec() should be used to pass in a tables address if a value
1834          other than the default internal tables were used at compile time.
1836    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1837        now diagnosed as an error. Previously, most of the time, a negative number
1838        would have been treated as zero, but if in addition "ovector" was passed as
1839        NULL, a crash could occur.
1841    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1842        new versions from the libtool 1.5 distribution (the last one is a copy of
1843        a file called libtool.m4). This seems to have fixed the need to patch
1844        "configure" to support Darwin 1.3 (which I used to do). However, I still
1845        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1846        workstation).
1848    24. Changed the PCRE licence to be the more standard "BSD" licence.
1851    Version 4.5 01-Dec-03
1852    ---------------------
1854     1. There has been some re-arrangement of the code for the match() function so
1855        that it can be compiled in a version that does not call itself recursively.
1856        Instead, it keeps those local variables that need separate instances for
1857        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1858        needs to "recurse". Keeping track of where control must go is done by means
1859        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1860        hide most of the details from the main code, and operates only if
1861        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1862        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1863        operating.
1865        To make it easier for callers to provide specially tailored get/free
1866        functions for this usage, two new functions, pcre_stack_malloc, and
1867        pcre_stack_free, are used. They are always called in strict stacking order,
1868        and the size of block requested is always the same.
1870        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1871        PCRE has been compiled to use the stack or the heap for recursion. The
1872        -C option of pcretest uses this to show which version is compiled.
1874        A new data escape \S, is added to pcretest; it causes the amounts of store
1875        obtained and freed by both kinds of malloc/free at match time to be added
1876        to the output.
1878     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1879        what's available on my current Linux desktop machine.
1881     3. When matching a UTF-8 string, the test for a valid string at the start has
1882        been extended. If start_offset is not zero, PCRE now checks that it points
1883        to a byte that is the start of a UTF-8 character. If not, it returns
1884        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1885        this is necessary because there may be backward assertions in the pattern.
1886        When matching the same subject several times, it may save resources to use
1887        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1889     4. The code for checking the validity of UTF-8 strings has been tightened so
1890        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1891        containing "overlong sequences".
1893     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1894        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1895        should have been "&", but it just so happened that all the cases this let
1896        through by mistake were picked up later in the function.
1898     6. I had used a variable called "isblank" - this is a C99 function, causing
1899        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1901     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1902        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1903        so the version is shown; (c) stop "make test" echoing "./RunTest".
1905     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1907     9. The prototype for memmove() for systems that don't have it was using
1908        size_t, but the inclusion of the header that defines size_t was later. I've
1909        moved the #includes for the C headers earlier to avoid this.
1911    10. Added some adjustments to the code to make it easier to compiler on certain
1912        special systems:
1914          (a) Some "const" qualifiers were missing.
1915          (b) Added the macro EXPORT before all exported functions; by default this
1916              is defined to be empty.
1917          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1918              that it reads its output file name as an argument instead of writing
1919              to the standard output and assuming this can be redirected.
1921    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1922        class containing characters with values greater than 255, PCRE compilation
1923        went into a loop.
1925    12. A recursive reference to a subpattern that was within another subpattern
1926        that had a minimum quantifier of zero caused PCRE to crash. For example,
1927        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1928        recursion. If the recursively-called subpattern itself had a zero repeat,
1929        that was OK.
1931    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1932        buffer into which it was copied (for escape processing) was still set at
1933        1024, so long lines caused crashes.
1935    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1936        "internal error: code overflow...". This applied to any character class
1937        that was followed by a possessive quantifier.
1939    15. Modified the Makefile to add libpcre.la as a prerequisite for
1940        libpcreposix.la because I was told this is needed for a parallel build to
1941        work.
1943    16. If a pattern that contained .* following optional items at the start was
1944        studied, the wrong optimizing data was generated, leading to matching
1945        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1946        matching string must start with a or b or c. The correct conclusion for
1947        this pattern is that a match can start with any character.
1950    Version 4.4 13-Aug-03
1951    ---------------------
1953     1. In UTF-8 mode, a character class containing characters with values between
1954        127 and 255 was not handled correctly if the compiled pattern was studied.
1955        In fixing this, I have also improved the studying algorithm for such
1956        classes (slightly).
1958     2. Three internal functions had redundant arguments passed to them. Removal
1959        might give a very teeny performance improvement.
1961     3. Documentation bug: the value of the capture_top field in a callout is *one
1962        more than* the number of the hightest numbered captured substring.
1964     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1965        in incorrectly linking with a previously installed version. They now link
1966        explicitly with libpcre.la.
1968     5. configure.in no longer needs to recognize Cygwin specially.
1970     6. A problem in pcre.in for Windows platforms is fixed.
1972     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1973        pcretest, it used to include the size of the study block as part of its
1974        output. Unfortunately, the structure contains a field that has a different
1975        size on different hardware architectures. This meant that the tests that
1976        showed this size failed. As the block is currently always of a fixed size,
1977        this information isn't actually particularly useful in pcretest output, so
1978        I have just removed it.
1980     8. Three pre-processor statements accidentally did not start in column 1.
1981        Sadly, there are *still* compilers around that complain, even though
1982        standard C has not required this for well over a decade. Sigh.
1984     9. In pcretest, the code for checking callouts passed small integers in the
1985        callout_data field, which is a void * field. However, some picky compilers
1986        complained about the casts involved for this on 64-bit systems. Now
1987        pcretest passes the address of the small integer instead, which should get
1988        rid of the warnings.
1990    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1991        both compile and run time, and gives an error if an invalid UTF-8 sequence
1992        is found. There is a option for disabling this check in cases where the
1993        string is known to be correct and/or the maximum performance is wanted.
1995    11. In response to a bug report, I changed one line in Makefile.in from
1997            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1998        to
1999            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2001        to look similar to other lines, but I have no way of telling whether this
2002        is the right thing to do, as I do not use Windows. No doubt I'll get told
2003        if it's wrong...
2006    Version 4.3 21-May-03
2007    ---------------------
2009    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2010       Makefile.
2012    2. Some refactoring to improve the quality of the code:
2014       (i)   The utf8_table... variables are now declared "const".
2016       (ii)  The code for \cx, which used the "case flipping" table to upper case
2017             lower case letters, now just substracts 32. This is ASCII-specific,
2018             but the whole concept of \cx is ASCII-specific, so it seems
2019             reasonable.
2021       (iii) PCRE was using its character types table to recognize decimal and
2022             hexadecimal digits in the pattern. This is silly, because it handles
2023             only 0-9, a-f, and A-F, but the character types table is locale-
2024             specific, which means strange things might happen. A private
2025             table is now used for this - though it costs 256 bytes, a table is
2026             much faster than multiple explicit tests. Of course, the standard
2027             character types table is still used for matching digits in subject
2028             strings against \d.
2030       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2031             ending in _t are). So I've renamed it as ESC_tee.
2033    3. The first argument for regexec() in the POSIX wrapper should have been
2034       defined as "const".
2036    4. Changed pcretest to use malloc() for its buffers so that they can be
2037       Electric Fenced for debugging.
2039    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2040       to read one or more bytes before the start of the subject string. Often this
2041       had no effect on PCRE's behaviour, but in some circumstances it could
2042       provoke a segmentation fault.
2044    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2045       to try to read one or more bytes before the start of the subject string.
2047    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2048       UTF-8 support could misbehave in various ways if the subject string
2049       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2050       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2051       back over UTF-8 characters.)
2054    Version 4.2 14-Apr-03
2055    ---------------------
2057    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2059    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2060         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2061         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2062         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2063         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2064           and BUILD_EXEEXT
2065         Note: automatic setting of the BUILD variables is not yet working
2066         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2067           compile-time but not at link-time
2068         [LINK]: use for linking executables only
2069         make different versions for Windows and non-Windows
2070         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2071           libraries
2072         [LINK_FOR_BUILD]: new variable
2073         [OBJEXT]: use throughout
2074         [EXEEXT]: use throughout
2075         <winshared>: new target
2076         <wininstall>: new target
2077         <dftables.o>: use native compiler
2078         <dftables>: use native linker
2079         <install>: handle Windows platform correctly
2080         <clean>: ditto
2081         <check>: ditto
2082         copy DLL to top builddir before testing
2084       As part of these changes, -no-undefined was removed again. This was reported
2085       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2086       in any case.
2088    3. Some tidies to get rid of compiler warnings:
2090       . In the match_data structure, match_limit was an unsigned long int, whereas
2091         match_call_count was an int. I've made them both unsigned long ints.
2093       . In pcretest the fact that a const uschar * doesn't automatically cast to
2094         a void * provoked a warning.
2096       . Turning on some more compiler warnings threw up some "shadow" variables
2097         and a few more missing casts.
2099    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2100       option, a class that contained a single character with a value between 128
2101       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2103    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2104       option, a class that contained several characters, but with at least one
2105       whose value was between 128 and 255 caused PCRE to crash.
2108    Version 4.1 12-Mar-03
2109    ---------------------
2111    1. Compiling with gcc -pedantic found a couple of places where casts were
2112    needed, and a string in dftables.c that was longer than standard compilers are
2113    required to support.
2115    2. Compiling with Sun's compiler found a few more places where the code could
2116    be tidied up in order to avoid warnings.
2118    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2119    first of these names is deprecated in the latest Autoconf in favour of the name
2120    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2121    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2122    analogy I have changed it to CFLAGS_FOR_BUILD.
2124    4. Added -no-undefined to the linking command in the Makefile, because this is
2125    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2126    linking step for the pcreposix library.
2128    5. PCRE was failing to diagnose the case of two named groups with the same
2129    name.
2131    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2132    literal character that is needed in the subject for a match, and scans along to
2133    ensure that it is present before embarking on the full matching process. This
2134    saves time in cases of nested unlimited repeats that are never going to match.
2135    Problem: the scan can take a lot of time if the subject is very long (e.g.
2136    megabytes), thus penalizing straightforward matches. It is now done only if the
2137    amount of subject to be scanned is less than 1000 bytes.
2139    7. A lesser problem with the same optimization is that it was recording the
2140    first character of an anchored pattern as "needed", thus provoking a search
2141    right along the subject, even when the first match of the pattern was going to
2142    fail. The "needed" character is now not set for anchored patterns, unless it
2143    follows something in the pattern that is of non-fixed length. Thus, it still
2144    fulfils its original purpose of finding quick non-matches in cases of nested
2145    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2148    Version 4.0 17-Feb-03
2149    ---------------------
2151    1. If a comment in an extended regex that started immediately after a meta-item
2152    extended to the end of string, PCRE compiled incorrect data. This could lead to
2153    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2155    2. Moved to autoconf 2.53 and libtool 1.4.2.
2157    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2158    the special perltest8 script is no longer needed - all the tests can be run
2159    from a single perltest script.
2161    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2162    by \s. It has now been removed in PCRE. This means it isn't recognized as
2163    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2164    class [:space:] *does* include VT, thereby creating a mess.
2166    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2167    space and tab.
2169    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2170    its new features into the main test script, reducing the number of scripts.
2172    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2173    were backward compatible, and made the (?i) apply to the whole pattern, as if
2174    /i were given. Now it behaves more logically, and applies the option setting
2175    only to what follows. PCRE has been changed to follow suit. However, if it
2176    finds options settings right at the start of the pattern, it extracts them into
2177    the global options, as before. Thus, they show up in the info data.
2179    8. Added support for the \Q...\E escape sequence. Characters in between are
2180    treated as literals. This is slightly different from Perl in that $ and @ are
2181    also handled as literals inside the quotes. In Perl, they will cause variable
2182    interpolation. Note the following examples:
2184        Pattern            PCRE matches      Perl matches
2186        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2187        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2188        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2190    For compatibility with Perl, \Q...\E sequences are recognized inside character
2191    classes as well as outside them.
2193    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2194    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2195    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2196    signed/unsigned warnings.
2198    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2199    option for pcretest, so I've replaced it by a simple function that does just
2200    that job.
2202    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2203    "pcregrep -".
2205    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2206    Java package. This provides some syntactic sugar for simple cases of what my
2207    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2208    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2209    item, you can use this simplified notation. Note that only makes sense with
2210    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2211    greediness, whatever the setting of the PCRE_UNGREEDY option.
2213    13. A change of greediness default within a pattern was not taking effect at
2214    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2215    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2216    was abstracted outside.
2218    14. PCRE now supports the \G assertion. It is true when the current matching
2219    position is at the start point of the match. This differs from \A when the
2220    starting offset is non-zero. Used with the /g option of pcretest (or similar
2221    code), it works in the same way as it does for Perl's /g option. If all
2222    alternatives of a regex begin with \G, the expression is anchored to the start
2223    match position, and the "anchored" flag is set in the compiled expression.
2225    15. Some bugs concerning the handling of certain option changes within patterns
2226    have been fixed. These applied to options other than (?ims). For example,
2227    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2228    been the other way round. Some of this was related to change 7 above.
2230    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2231    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2232    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2233    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2235    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2236    mode. Unlike ".", it always matches newline, whatever the setting of
2237    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2238    assertions. Perl allows it, but it doesn't (in general) work because it can't
2239    calculate the length of the lookbehind. At least, that's the case for Perl
2240    5.8.0 - I've been told they are going to document that it doesn't work in
2241    future.
2243    18. Added an error diagnosis for escapes that PCRE does not support: these are
2244    \L, \l, \N, \P, \p, \U, \u, and \X.
2246    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2247    reading past the end of the pattern in cases such as /[abcd/.
2249    20. PCRE was getting more memory than necessary for patterns with classes that
2250    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2252    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2253    compiling PCRE for use with Virtual Pascal.
2255    22. Small fix to the Makefile to make it work properly if the build is done
2256    outside the source tree.
2258    23. Added a new extension: a condition to go with recursion. If a conditional
2259    subpattern starts with (?(R) the "true" branch is used if recursion has
2260    happened, whereas the "false" branch is used only at the top level.
2262    24. When there was a very long string of literal characters (over 255 bytes
2263    without UTF support, over 250 bytes with UTF support), the computation of how
2264    much memory was required could be incorrect, leading to segfaults or other
2265    strange effects.
2267    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2268    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2269    there was a subsequent back reference to those brackets. This meant that, for
2270    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2271    possible to check for precisely this case. All we can do is abandon the
2272    optimization if .* occurs inside capturing brackets when there are any back
2273    references whatsoever. (See below for a better fix that came later.)
2275    26. The handling of the optimization for finding the first character of a
2276    non-anchored pattern, and for finding a character that is required later in the
2277    match were failing in some cases. This didn't break the matching; it just
2278    failed to optimize when it could. The way this is done has been re-implemented.
2280    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2282    28. Added a new feature that provides some of the functionality that Perl
2283    provides with (?{...}). The facility is termed a "callout". The way it is done
2284    in PCRE is for the caller to provide an optional function, by setting
2285    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2286    global variable. By default it is unset, which disables all calling out. To get
2287    the function called, the regex must include (?C) at appropriate points. This
2288    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2289    This provides a means of identifying different callout points. When PCRE
2290    reaches such a point in the regex, if pcre_callout has been set, the external
2291    function is called. It is provided with data in a structure called
2292    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2293    matching continues; if it returns a non-zero value, the match at the current
2294    point fails. However, backtracking will occur if possible. [This was changed
2295    later and other features added - see item 49 below.]
2297    29. pcretest is upgraded to test the callout functionality. It provides a
2298    callout function that displays information. By default, it shows the start of
2299    the match and the current position in the text. There are some new data escapes
2300    to vary what happens:
2302        \C+         in addition, show current contents of captured substrings
2303        \C-         do not supply a callout function
2304        \C!n        return 1 when callout number n is reached
2305        \C!n!m      return 1 when callout number n is reached for the mth time
2307    30. If pcregrep was called with the -l option and just a single file name, it
2308    output "<stdin>" if a match was found, instead of the file name.
2310    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2311    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2312    pcre_exec(). This saves a malloc/free per call. The default value of
2313    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2314    when configuring.
2316    32. The default maximum size of a compiled pattern is 64K. There have been a
2317    few cases of people hitting this limit. The code now uses macros to handle the
2318    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2319    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2320    configuring. Tests 2 and 5 work only with 2-byte links because they output
2321    debugging information about compiled patterns.
2323    33. Internal code re-arrangements:
2325    (a) Moved the debugging function for printing out a compiled regex into
2326        its own source file (printint.c) and used #include to pull it into
2327        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2328        separate copies.
2330    (b) Defined the list of op-code names for debugging as a macro in
2331        internal.h so that it is next to the definition of the opcodes.
2333    (c) Defined a table of op-code lengths for simpler skipping along compiled
2334        code. This is again a macro in internal.h so that it is next to the
2335        definition of the opcodes.
2337    34. Added support for recursive calls to individual subpatterns, along the
2338    lines of Robin Houston's patch (but implemented somewhat differently).
2340    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2341    allow it to read and process whole directories in Win32. This code was
2342    contributed by Lionel Fourquaux; it has not been tested by me.
2344    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2345    used to name a group. Names consist of alphanumerics and underscores, and must
2346    be unique. Back references use the syntax (?P=name) and recursive calls use
2347    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2348    numbers. The function pcre_fullinfo() can be used after compilation to extract
2349    a name/number map. There are three relevant calls:
2351      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2352      PCRE_INFO_NAMECOUNT            yields the number of entries
2353      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2355    The map is a vector of fixed-size entries. The size of each entry depends on
2356    the length of the longest name used. The first two bytes of each entry are the
2357    group number, most significant byte first. There follows the corresponding
2358    name, zero terminated. The names are in alphabetical order.
2360    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2361    case instead of 255. Making it the same both with and without UTF-8 support
2362    means that the same test output works with both.
2364    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2365    calling malloc() with a zero argument.
2367    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2368    optimization. I've improved things by keeping a bitmap of backreferences with
2369    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2370    fact referenced, the optimization can be applied. It is unlikely that a
2371    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2372    the match to follow \n) will appear inside brackets with a number greater than
2373    31, but if it does, any back reference > 31 suppresses the optimization.
2375    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2376    of disabling numbered capturing parentheses. Any opening parenthesis that is
2377    not followed by ? behaves as if it were followed by ?: but named parentheses
2378    can still be used for capturing (and they will acquire numbers in the usual
2379    way).
2381    41. Redesigned the return codes from the match() function into yes/no/error so
2382    that errors can be passed back from deep inside the nested calls. A malloc
2383    failure while inside a recursive subpattern call now causes the
2384    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2386    42. It is now possible to set a limit on the number of times the match()
2387    function is called in a call to pcre_exec(). This facility makes it possible to
2388    limit the amount of recursion and backtracking, though not in a directly
2389    obvious way, because the match() function is used in a number of different
2390    circumstances. The count starts from zero for each position in the subject
2391    string (for non-anchored patterns). The default limit is, for compatibility, a
2392    large number, namely 10 000 000. You can change this in two ways:
2394    (a) When configuring PCRE before making, you can use --with-match-limit=n
2395        to set a default value for the compiled library.
2397    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2398        a different value is set. See 45 below.
2400    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2402    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2403    of things that can be changed at compile time. The first argument specifies
2404    what is wanted and the second points to where the information is to be placed.
2405    The current list of available information is:
2407      PCRE_CONFIG_UTF8
2409    The output is an integer that is set to one if UTF-8 support is available;
2410    otherwise it is set to zero.
2414    The output is an integer that it set to the value of the code that is used for
2415    newline. It is either LF (10) or CR (13).
2419    The output is an integer that contains the number of bytes used for internal
2420    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2424    The output is an integer that contains the threshold above which the POSIX
2425    interface uses malloc() for output vectors. See item 31 above.
2429    The output is an unsigned integer that contains the default limit of the number
2430    of match() calls in a pcre_exec() execution. See 42 above.
2432    44. pcretest has been upgraded by the addition of the -C option. This causes it
2433    to extract all the available output from the new pcre_config() function, and to
2434    output it. The program then exits immediately.
2436    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2437    order to support additional features. One way would have been to define
2438    pcre_exec2() (for example) with extra arguments, but this would not have been
2439    extensible, and would also have required all calls to the original function to
2440    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2441    is used for passing in "extra" data from pcre_study().
2443    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2444    contains the following fields:
2446      flags         a bitmap indicating which of the following fields are set
2447      study_data    opaque data from pcre_study()
2448      match_limit   a way of specifying a limit on match() calls for a specific
2449                      call to pcre_exec()
2450      callout_data  data for callouts (see 49 below)
2452    The flag bits are also defined in pcre.h, and are
2458    The pcre_study() function now returns one of these new pcre_extra blocks, with
2459    the actual study data pointed to by the study_data field, and the
2460    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2461    before. That is, this change is entirely upwards-compatible and requires no
2462    change to existing code.
2464    If you want to pass in additional data to pcre_exec(), you can either place it
2465    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2466    block.
2468    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2469    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2470    times with different match limits, until it finds the minimum value needed for
2471    pcre_exec() to complete. The value is then output. This can be instructive; for
2472    most simple matches the number is quite small, but for pathological cases it
2473    gets very large very quickly.
2475    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2476    returns the size of the data block pointed to by the study_data field in a
2477    pcre_extra block, that is, the value that was passed as the argument to
2478    pcre_malloc() when PCRE was getting memory in which to place the information
2479    created by pcre_study(). The fourth argument should point to a size_t variable.
2480    pcretest has been extended so that this information is shown after a successful
2481    pcre_study() call when information about the compiled regex is being displayed.
2483    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2484    because what follows is always an absolute path. (Later: it turns out that this
2485    is more than cosmetic for MinGW, because it doesn't like empty path
2486    components.)
2488    49. Some changes have been made to the callout feature (see 28 above):
2490    (i)  A callout function now has three choices for what it returns:
2492           0  =>  success, carry on matching
2493         > 0  =>  failure at this point, but backtrack if possible
2494         < 0  =>  serious error, return this value from pcre_exec()
2496         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2497         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2498         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2499         use by callout functions. It will never be used by PCRE itself.
2501    (ii) The pcre_extra structure (see 45 above) has a void * field called
2502         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2503         pcre_callout_block structure has a field of the same name. The contents of
2504         the field passed in the pcre_extra structure are passed to the callout
2505         function in the corresponding field in the callout block. This makes it
2506         easier to use the same callout-containing regex from multiple threads. For
2507         testing, the pcretest program has a new data escape
2509           \C*n        pass the number n (may be negative) as callout_data
2511         If the callout function in pcretest receives a non-zero value as
2512         callout_data, it returns that value.
2514    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2515    there were some redundant $(CFLAGS) in commands that are now specified as
2516    $(LINK), which already includes $(CFLAGS).
2518    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2519    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2520    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2521    one-byte characters throughout. Note that case-insensitive matching applies
2522    only to characters whose values are less than 256. PCRE doesn't support the
2523    notion of cases for higher-valued characters.
2525    (i)   A character class whose characters are all within 0-255 is handled as
2526          a bit map, and the map is inverted for negative classes. Previously, a
2527          character > 255 always failed to match such a class; however it should
2528          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2530    (ii)  A negated character class with a single character < 255 is coded as
2531          "not this character" (OP_NOT). This wasn't working properly when the test
2532          character was multibyte, either singly or repeated.
2534    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2535          mode, for example: \x{100}{2,3}.
2537    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2538          singly or repeated) now correctly test multibyte characters. However,
2539          PCRE doesn't recognize any characters with values greater than 255 as
2540          digits, spaces, or word characters. Such characters always match \D, \S,
2541          and \W, and never match \d, \s, or \w.
2543    (v)   Classes may now contain characters and character ranges with values
2544          greater than 255. For example: [ab\x{100}-\x{400}].
2546    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2547          PCRE in UTF-8 mode.
2549    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2550    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2551    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2552    value.)
2554    53. The single man page has become too large. I have therefore split it up into
2555    a number of separate man pages. These also give rise to individual HTML pages;
2556    these are now put in a separate directory, and there is an index.html page that
2557    lists them all. Some hyperlinking between the pages has been installed.
2559    54. Added convenience functions for handling named capturing parentheses.
2561    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2562    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2563    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2564    are faulted.
2566    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2567    calling configure. These values are used when compiling the dftables.c program
2568    which is run to generate the source of the default character tables. They
2569    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2570    you will need to set these values.
2572    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2575    Version 3.9 02-Jan-02
2576    ---------------------
2578    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2580    2. If --disable-static was given, the building process failed when trying to
2581    build pcretest and pcregrep. (For some reason it was using libtool to compile
2582    them, which is not right, as they aren't part of the library.)
2585    Version 3.8 18-Dec-01
2586    ---------------------
2588    1. The experimental UTF-8 code was completely screwed up. It was packing the
2589    bytes in the wrong order. How dumb can you get?
2592    Version 3.7 29-Oct-01
2593    ---------------------
2595    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2596    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2597    this didn't happen under Solaris 8, where I normally test things.
2599    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2600    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2601    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2602    this fix an hour or so after the initial 3.7 release.)
2605    Version 3.6 23-Oct-01
2606    ---------------------
2608    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2609    offsets passed as NULL with zero offset count.
2611    2. The config.guess and config.sub files had not been updated when I moved to
2612    the latest autoconf.
2615    Version 3.5 15-Aug-01
2616    ---------------------
2618    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2619    had been forgotten.
2621    2. By using declared but undefined structures, we can avoid using "void"
2622    definitions in pcre.h while keeping the internal definitions of the structures
2623    private.
2625    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2626    user point of view, this means that both static and shared libraries are built
2627    by default, but this can be individually controlled. More of the work of
2628    handling this static/shared cases is now inside libtool instead of PCRE's make
2629    file.
2631    4. The pcretest utility is now installed along with pcregrep because it is
2632    useful for users (to test regexs) and by doing this, it automatically gets
2633    relinked by libtool. The documentation has been turned into a man page, so
2634    there are now .1, .txt, and .html versions in /doc.
2636    5. Upgrades to pcregrep:
2637       (i)   Added long-form option names like gnu grep.
2638       (ii)  Added --help to list all options with an explanatory phrase.
2639       (iii) Added -r, --recursive to recurse into sub-directories.
2640       (iv)  Added -f, --file to read patterns from a file.
2642    6. pcre_exec() was referring to its "code" argument before testing that
2643    argument for NULL (and giving an error if it was NULL).
2645    7. Upgraded Makefile.in to allow for compiling in a different directory from
2646    the source directory.
2648    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2649    options bits, the pointer it was passed was to an int instead of to an unsigned
2650    long int. This mattered only on 64-bit systems.
2652    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2653    generated) instead of pcre.in, which it its source. Also made the same change
2654    in several of the .c files.
2656    10. A new release of gcc defines printf() as a macro, which broke pcretest
2657    because it had an ifdef in the middle of a string argument for printf(). Fixed
2658    by using separate calls to printf().
2660    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2661    script, to force use of CR or LF instead of \n in the source. On non-Unix
2662    systems, the value can be set in config.h.
2664    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2665    absolute limit. Changed the text of the error message to make this clear, and
2666    likewise updated the man page.
2668    13. The limit of 99 on the number of capturing subpatterns has been removed.
2669    The new limit is 65535, which I hope will not be a "real" limit.
2672    Version 3.4 22-Aug-00
2673    ---------------------
2675    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2677    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2680  Version 3.3 01-Aug-00  Version 3.3 01-Aug-00
2681  ---------------------  ---------------------

Removed from v.49  
changed lines
  Added in v.351

  ViewVC Help
Powered by ViewVC 1.1.5