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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 354 by ph10, Mon Jul 7 16:30:33 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.0 02 Jul-08
5    ---------------------
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
17    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18        a group with a zero qualifier. The result of the study could be incorrect,
19        or the function might crash, depending on the pattern.
21    4.  Caseless matching was not working for non-ASCII characters in back
22        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23        It now works when Unicode Property Support is available.
26    Version 7.7 07-May-08
27    ---------------------
29    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
30        a string to a long long, pretend we don't even have a long long." This is
31        done by checking for the strtoq, strtoll, and _strtoi64 functions.
33    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
34        pre-7.6 versions, which defined a global no_arg variable instead of putting
35        it in the RE class. (See also #8 below.)
37    3.  Remove a line of dead code, identified by coverity and reported by Nuno
38        Lopes.
40    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
42        (1) The include/exclude patterns were being applied to the whole pathnames
43            of files, instead of just to the final components.
45        (2) If there was more than one level of directory, the subdirectories were
46            skipped unless they satisfied the include/exclude conditions. This is
47            inconsistent with GNU grep (and could even be seen as contrary to the
48            pcregrep specification - which I improved to make it absolutely clear).
49            The action now is always to scan all levels of directory, and just
50            apply the include/exclude patterns to regular files.
52    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
53        --exclude_dir in the tests to avoid scanning .svn directories.
55    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
56        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
57        doesn't support NULs in patterns.
59    7.  Added some missing "const"s to declarations of static tables in
60        pcre_compile.c and pcre_dfa_exec.c.
62    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
63        caused by fix #2  above. (Subsequently also a second patch to fix the
64        first patch. And a third patch - this was a messy problem.)
66    9.  Applied Craig's patch to remove the use of push_back().
68    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
69        matching function regexec().
71    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
72        which, however, unlike Perl's \g{...}, are subroutine calls, not back
73        references. PCRE supports relative numbers with this syntax (I don't think
74        Oniguruma does).
76    12. Previously, a group with a zero repeat such as (...){0} was completely
77        omitted from the compiled regex. However, this means that if the group
78        was called as a subroutine from elsewhere in the pattern, things went wrong
79        (an internal error was given). Such groups are now left in the compiled
80        pattern, with a new opcode that causes them to be skipped at execution
81        time.
83    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
84        to the way PCRE behaves:
86        (a) A lone ] character is dis-allowed (Perl treats it as data).
88        (b) A back reference to an unmatched subpattern matches an empty string
89            (Perl fails the current match path).
91        (c) A data ] in a character class must be notated as \] because if the
92            first data character in a class is ], it defines an empty class. (In
93            Perl it is not possible to have an empty class.) The empty class []
94            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
95            The negative empty class [^] matches any one character, independently
96            of the DOTALL setting.
98    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
99        non-existent subpattern following a character class starting with ']' and
100        containing () gave an internal compiling error instead of "reference to
101        non-existent subpattern". Fortunately, when the pattern did exist, the
102        compiled code was correct. (When scanning forwards to check for the
103        existencd of the subpattern, it was treating the data ']' as terminating
104        the class, so got the count wrong. When actually compiling, the reference
105        was subsequently set up correctly.)
107    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
108        it was being rejected as not supported by pcre_dfa_exec(), even though
109        other assertions are supported. I have made pcre_dfa_exec() support
110        (*FAIL).
112    16. The implementation of 13c above involved the invention of a new opcode,
113        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
114        cannot be changed at match time, I realized I could make a small
115        improvement to matching performance by compiling OP_ALLANY instead of
116        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
117        on the OP_ANY path.
119    17. Compiling pcretest on Windows with readline support failed without the
120        following two fixes: (1) Make the unistd.h include conditional on
121        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
123    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
124        ncurses library to be included for pcretest when ReadLine support is
125        requested, but also to allow for it to be overridden. This patch came from
126        Daniel Bergström.
128    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
129        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
130        any errors with the current Unicode tables. Thanks to Peter Kankowski for
131        spotting this.
134    Version 7.6 28-Jan-08
135    ---------------------
137    1.  A character class containing a very large number of characters with
138        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
139        overflow.
141    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
142        HAVE_LONG_LONG is not defined.
144    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
145        bring them up to date and include new features. This patch includes:
147        - Fixed PH's badly added libz and libbz2 support.
148        - Fixed a problem with static linking.
149        - Added pcredemo. [But later removed - see 7 below.]
150        - Fixed dftables problem and added an option.
151        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
152            HAVE_LONG_LONG.
153        - Added readline support for pcretest.
154        - Added an listing of the option settings after cmake has run.
156    4.  A user submitted a patch to Makefile that makes it easy to create
157        "pcre.dll" under mingw when using Configure/Make. I added stuff to
158        Makefile.am that cause it to include this special target, without
159        affecting anything else. Note that the same mingw target plus all
160        the other distribution libraries and programs are now supported
161        when configuring with CMake (see 6 below) instead of with
162        Configure/Make.
164    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
165        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
166        exported in the Windows port". It has not yet been confirmed that the patch
167        solves the problem, but it does no harm.
169    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
170        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
171        with CMake, and also correct the comment about stack recursion.
173    7.  Remove the automatic building of pcredemo from the ./configure system and
174        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
175        of a program that users should build themselves after PCRE is installed, so
176        building it automatically is not really right. What is more, it gave
177        trouble in some build environments.
179    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
182    Version 7.5 10-Jan-08
183    ---------------------
185    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
186        values in parens when parsing an RE using the C++ wrapper."
188    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
189        Characters greater than 255 were excluded from the class instead of being
190        included.
192    3.  The same bug as (2) above applied to negated POSIX classes such as
193        [:^space:].
195    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
196        defined or documented. It seems to have been a typo for PCRE_STATIC, so
197        I have changed it.
199    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
200        first named subpattern) and a construct such as (?&a) would reference the
201        first named subpattern whose name started with "a" (in other words, the
202        length check was missing). Both these problems are fixed. "Subpattern name
203        expected" is now given for (?&) (a zero-length name), and this patch also
204        makes it give the same error for \k'' (previously it complained that that
205        was a reference to a non-existent subpattern).
207    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
208        this is right because (?- can be followed by option settings as well as by
209        digits. I have, however, made the messages clearer.
211    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
212        than the number used in the conditional) now cause a compile-time error.
213        This is actually not compatible with Perl, which accepts such patterns, but
214        treats the conditional as always being FALSE (as PCRE used to), but it
215        seems to me that giving a diagnostic is better.
217    8.  Change "alphameric" to the more common word "alphanumeric" in comments
218        and messages.
220    9.  Fix two occurrences of "backslash" in comments that should have been
221        "backspace".
223    10. Remove two redundant lines of code that can never be obeyed (their function
224        was moved elsewhere).
226    11. The program that makes PCRE's Unicode character property table had a bug
227        which caused it to generate incorrect table entries for sequences of
228        characters that have the same character type, but are in different scripts.
229        It amalgamated them into a single range, with the script of the first of
230        them. In other words, some characters were in the wrong script. There were
231        thirteen such cases, affecting characters in the following ranges:
233          U+002b0 - U+002c1
234          U+0060c - U+0060d
235          U+0061e - U+00612
236          U+0064b - U+0065e
237          U+0074d - U+0076d
238          U+01800 - U+01805
239          U+01d00 - U+01d77
240          U+01d9b - U+01dbf
241          U+0200b - U+0200f
242          U+030fc - U+030fe
243          U+03260 - U+0327f
244          U+0fb46 - U+0fbb1
245          U+10450 - U+1049d
247    12. The -o option (show only the matching part of a line) for pcregrep was not
248        compatible with GNU grep in that, if there was more than one match in a
249        line, it showed only the first of them. It now behaves in the same way as
250        GNU grep.
252    13. If the -o and -v options were combined for pcregrep, it printed a blank
253        line for every non-matching line. GNU grep prints nothing, and pcregrep now
254        does the same. The return code can be used to tell if there were any
255        non-matching lines.
257    14. Added --file-offsets and --line-offsets to pcregrep.
259    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
260        infinitely looping recursion. The bug was that positive lookaheads were not
261        being skipped when checking for a possible empty match (negative lookaheads
262        and both kinds of lookbehind were skipped).
264    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
265        inclusion of <windows.h> to before rather than after the definition of
266        INVALID_FILE_ATTRIBUTES (patch from David Byron).
268    17. Specifying a possessive quantifier with a specific limit for a Unicode
269        character property caused pcre_compile() to compile bad code, which led at
270        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
271        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
272        caused the error; without that there was no problem.
274    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
276    19. Added --enable-pcretest-libreadline.
278    20. In pcrecpp.cc, the variable 'count' was incremented twice in
279        RE::GlobalReplace(). As a result, the number of replacements returned was
280        double what it should be. I removed one of the increments, but Craig sent a
281        later patch that removed the other one (the right fix) and added unit tests
282        that check the return values (which was not done before).
284    21. Several CMake things:
286        (1) Arranged that, when cmake is used on Unix, the libraries end up with
287            the names libpcre and libpcreposix, not just pcre and pcreposix.
289        (2) The above change means that pcretest and pcregrep are now correctly
290            linked with the newly-built libraries, not previously installed ones.
294    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
295        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
296        UTF-8 newline character). The key issue is that the pattern starts .*;
297        this means that the match must be either at the beginning, or after a
298        newline. The bug was in the code for advancing after a failed match and
299        checking that the new position followed a newline. It was not taking
300        account of UTF-8 characters correctly.
302    23. PCRE was behaving differently from Perl in the way it recognized POSIX
303        character classes. PCRE was not treating the sequence [:...:] as a
304        character class unless the ... were all letters. Perl, however, seems to
305        allow any characters between [: and :], though of course it rejects as
306        unknown any "names" that contain non-letters, because all the known class
307        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
308        for example, whereas PCRE did not - it did not recognize a POSIX character
309        class. This seemed a bit dangerous, so the code has been changed to be
310        closer to Perl. The behaviour is not identical to Perl, because PCRE will
311        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
312        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
313        Perl does, and where it didn't before.
315    24. Rewrite so as to remove the single use of %n from pcregrep because in some
316        Windows environments %n is disabled by default.
319    Version 7.4 21-Sep-07
320    ---------------------
322    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
323        means that a class such as [\s] counted as "explicit reference to CR or
324        LF". That isn't really right - the whole point of the change was to try to
325        help when there was an actual mention of one of the two characters. So now
326        the change happens only if \r or \n (or a literal CR or LF) character is
327        encountered.
329    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
330        of both had grown to the point where there were only 3 bits left.
331        Fortunately, there was spare space in the data structure, and so I have
332        moved the internal flags into a new 16-bit field to free up more option
333        bits.
335    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
336        but did not set the internal JCHANGED flag - either of these is enough to
337        control the way the "get" function works - but the PCRE_INFO_JCHANGED
338        facility is supposed to tell if (?J) was ever used, so now (?J) at the
339        start sets both bits.
341    4.  Added options (at build time, compile time, exec time) to change \R from
342        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
344    5.  doc/pcresyntax.html was missing from the distribution.
346    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
347        compatibility, even though it is no longer used.
349    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
350        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
351        windows.h file is present (where different names are used). [This was
352        reversed later after testing - see 16 below.]
354    8.  Changed all #include <config.h> to #include "config.h". There were also
355        some further <pcre.h> cases that I changed to "pcre.h".
357    9.  When pcregrep was used with the --colour option, it missed the line ending
358        sequence off the lines that it output.
360    10. It was pointed out to me that arrays of string pointers cause lots of
361        relocations when a shared library is dynamically loaded. A technique of
362        using a single long string with a table of offsets can drastically reduce
363        these. I have refactored PCRE in four places to do this. The result is
364        dramatic:
366          Originally:                          290
367          After changing UCP table:            187
368          After changing error message table:   43
369          After changing table of "verbs"       36
370          After changing table of Posix names   22
372        Thanks to the folks working on Gregex for glib for this insight.
374    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
375        unicode-properties was also set.
377    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
379    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
380        checked only for CRLF.
382    14. Added casts to pcretest.c to avoid compiler warnings.
384    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
386    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
387        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
388        entirely. This removes changes made in 7 above.
390    17. The CMake files have been updated, and there is now more information about
391        building with CMake in the NON-UNIX-USE document.
394    Version 7.3 28-Aug-07
395    ---------------------
397     1. In the rejigging of the build system that eventually resulted in 7.1, the
398        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
399        brackets there is not right, since it causes compilers to look for an
400        installed pcre.h, not the version that is in the source that is being
401        compiled (which of course may be different). I have changed it back to:
403          #include "pcre.h"
405        I have a vague recollection that the change was concerned with compiling in
406        different directories, but in the new build system, that is taken care of
407        by the VPATH setting the Makefile.
409     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
410        when the subject happened to end in the byte 0x85 (e.g. if the last
411        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
412        characters but of course it shouldn't be taken as a newline when it is part
413        of another character. The bug was that, for an unlimited repeat of . in
414        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
415        characters when looking for a newline.
417     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
419     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
420        in debug output.
422     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
423        long printing in the pcrecpp unittest when running under MinGW.
425     6. ESC_K was left out of the EBCDIC table.
427     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
428        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
429        limit also applies to "virtual nesting" when a pattern is recursive, and in
430        this case 1000 isn't so big. I have been able to remove this limit at the
431        expense of backing off one optimization in certain circumstances. Normally,
432        when pcre_exec() would call its internal match() function recursively and
433        immediately return the result unconditionally, it uses a "tail recursion"
434        feature to save stack. However, when a subpattern that can match an empty
435        string has an unlimited repetition quantifier, it no longer makes this
436        optimization. That gives it a stack frame in which to save the data for
437        checking that an empty string has been matched. Previously this was taken
438        from the 1000-entry workspace that had been reserved. So now there is no
439        explicit limit, but more stack is used.
441     8. Applied Daniel's patches to solve problems with the import/export magic
442        syntax that is required for Windows, and which was going wrong for the
443        pcreposix and pcrecpp parts of the library. These were overlooked when this
444        problem was solved for the main library.
446     9. There were some crude static tests to avoid integer overflow when computing
447        the size of patterns that contain repeated groups with explicit upper
448        limits. As the maximum quantifier is 65535, the maximum group length was
449        set at 30,000 so that the product of these two numbers did not overflow a
450        32-bit integer. However, it turns out that people want to use groups that
451        are longer than 30,000 bytes (though not repeat them that many times).
452        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
453        made it possible to implement the integer overflow checks in a much more
454        dynamic way, which I have now done. The artificial limitation on group
455        length has been removed - we now have only the limit on the total length of
456        the compiled pattern, which depends on the LINK_SIZE setting.
458    10. Fixed a bug in the documentation for get/copy named substring when
459        duplicate names are permitted. If none of the named substrings are set, the
460        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
461        empty string.
463    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
464        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
465        because the ] is interpreted as the first data character and the
466        terminating ] is not found. PCRE has been made compatible with Perl in this
467        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
468        cause memory overwriting.
470    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
471        string has been matched (to stop an infinite loop). It was not recognizing
472        a conditional subpattern that could match an empty string if that
473        subpattern was within another subpattern. For example, it looped when
474        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
475        condition was not nested. This bug has been fixed.
477    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
478        past the start of the subject in the presence of bytes with the top bit
479        set, for example "\x8aBCD".
481    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
482        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
484    14. Optimized (?!) to (*FAIL).
486    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
487        This restricts code points to be within the range 0 to 0x10FFFF, excluding
488        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
489        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
490        does: it's just the validity check that is more restrictive.
492    16. Inserted checks for integer overflows during escape sequence (backslash)
493        processing, and also fixed erroneous offset values for syntax errors during
494        backslash processing.
496    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
497        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
499    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
500        caused an overrun.
502    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
503        something other than just ASCII characters) inside a group that had an
504        unlimited repeat caused a loop at compile time (while checking to see
505        whether the group could match an empty string).
507    20. Debugging a pattern containing \p or \P could cause a crash. For example,
508        [\P{Any}] did so. (Error in the code for printing property names.)
510    21. An orphan \E inside a character class could cause a crash.
512    22. A repeated capturing bracket such as (A)? could cause a wild memory
513        reference during compilation.
515    23. There are several functions in pcre_compile() that scan along a compiled
516        expression for various reasons (e.g. to see if it's fixed length for look
517        behind). There were bugs in these functions when a repeated \p or \P was
518        present in the pattern. These operators have additional parameters compared
519        with \d, etc, and these were not being taken into account when moving along
520        the compiled data. Specifically:
522        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
523            length.
525        (b) An item such as \pL+ within a repeated group could cause crashes or
526            loops.
528        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
529            "reference to non-existent subpattern" error.
531        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
533    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
534        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
536    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
538    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
539        character were causing crashes (broken optimization).
541    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
542        \p or \P) caused a compile-time loop.
544    28. More problems have arisen in unanchored patterns when CRLF is a valid line
545        break. For example, the unstudied pattern [\r\n]A does not match the string
546        "\r\nA" because change 7.0/46 below moves the current point on by two
547        characters after failing to match at the start. However, the pattern \nA
548        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
549        the same is true. There doesn't seem any very clean way out of this, but
550        what I have chosen to do makes the common cases work: PCRE now takes note
551        of whether there can be an explicit match for \r or \n anywhere in the
552        pattern, and if so, 7.0/46 no longer applies. As part of this change,
553        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
554        pattern has explicit CR or LF references.
556    29. Added (*CR) etc for changing newline setting at start of pattern.
559    Version 7.2 19-Jun-07
560    ---------------------
562     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
563        which is apparently normally available under Windows.
565     2. Re-jig the pcregrep tests with different newline settings in an attempt
566        to make them independent of the local environment's newline setting.
568     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
570     4. Some of the "internals" tests were previously cut out when the link size
571        was not 2, because the output contained actual offsets. The recent new
572        "Z" feature of pcretest means that these can be cut out, making the tests
573        usable with all link sizes.
575     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
576        stack recursion. This gives a massive performance boost under BSD, but just
577        a small improvement under Linux. However, it saves one field in the frame
578        in all cases.
580     6. Added more features from the forthcoming Perl 5.10:
582        (a) (?-n) (where n is a string of digits) is a relative subroutine or
583            recursion call. It refers to the nth most recently opened parentheses.
585        (b) (?+n) is also a relative subroutine call; it refers to the nth next
586            to be opened parentheses.
588        (c) Conditions that refer to capturing parentheses can be specified
589            relatively, for example, (?(-2)... or (?(+3)...
591        (d) \K resets the start of the current match so that everything before
592            is not part of it.
594        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
596        (f) \g{name} is another synonym - part of Perl 5.10's unification of
597            reference syntax.
599        (g) (?| introduces a group in which the numbering of parentheses in each
600            alternative starts with the same number.
602        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
604     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
607     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
608        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
609        for detecting groups that can match an empty string.
611     9. A pattern with a very large number of alternatives (more than several
612        hundred) was running out of internal workspace during the pre-compile
613        phase, where pcre_compile() figures out how much memory will be needed. A
614        bit of new cunning has reduced the workspace needed for groups with
615        alternatives. The 1000-alternative test pattern now uses 12 bytes of
616        workspace instead of running out of the 4096 that are available.
618    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
620    11. Applied patch from Google to remove an optimization that didn't quite work.
621        The report of the bug said:
623          pcrecpp::RE("a*").FullMatch("aaa") matches, while
624          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
625          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
627    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
628        it matched the wrong number of bytes.
631    Version 7.1 24-Apr-07
632    ---------------------
634     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
635        that is more "standard", making use of automake and other Autotools. There
636        is some re-arrangement of the files and adjustment of comments consequent
637        on this.
639     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
640        for recursive directory scanning broke on some systems because the files
641        are not scanned in any specific order and on different systems the order
642        was different. A call to "sort" has been inserted into RunGrepTest for the
643        approprate test as a short-term fix. In the longer term there may be an
644        alternative.
646     3. I had an email from Eric Raymond about problems translating some of PCRE's
647        man pages to HTML (despite the fact that I distribute HTML pages, some
648        people do their own conversions for various reasons). The problems
649        concerned the use of low-level troff macros .br and .in. I have therefore
650        removed all such uses from the man pages (some were redundant, some could
651        be replaced by .nf/.fi pairs). The 132html script that I use to generate
652        HTML has been updated to handle .nf/.fi and to complain if it encounters
653        .br or .in.
655     4. Updated comments in configure.ac that get placed in config.h.in and also
656        arranged for config.h to be included in the distribution, with the name
657        config.h.generic, for the benefit of those who have to compile without
658        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
660     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
661        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
662        makevp.bat for the current PCRE, using the additional files
663        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
665     6. A Windows user reported a minor discrepancy with test 2, which turned out
666        to be caused by a trailing space on an input line that had got lost in his
667        copy. The trailing space was an accident, so I've just removed it.
669     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
670        that is needed.
672     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
673        as "const" (a) because they are and (b) because it helps the PHP
674        maintainers who have recently made a script to detect big data structures
675        in the php code that should be moved to the .rodata section. I remembered
676        to update Builducptable as well, so it won't revert if ucptable.h is ever
677        re-created.
679     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
680        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
681        order to be able to cut out the UTF-8 tables in the latter when UTF-8
682        support is not required. This saves 1.5-2K of code, which is important in
683        some applications.
685        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
686        so as not to refer to the tables, even though these functions will never be
687        called when UTF-8 support is disabled. Otherwise there are problems with a
688        shared library.
690    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
692        (a) It was defining its arguments as char * instead of void *.
694        (b) It was assuming that all moves were upwards in memory; this was true
695            a long time ago when I wrote it, but is no longer the case.
697        The emulated memove() is provided for those environments that have neither
698        memmove() nor bcopy(). I didn't think anyone used it these days, but that
699        is clearly not the case, as these two bugs were recently reported.
701    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
702        and Detrail to create the HTML documentation, the .txt form of the man
703        pages, and it removes trailing spaces from listed files. It also creates
704        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
705        case, it wraps all the #defines with #ifndefs. This script should be run
706        before "make dist".
708    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
709        with Unicode property support.
711        (a) For a maximizing quantifier, if the two different cases of the
712            character were of different lengths in their UTF-8 codings (there are
713            some cases like this - I found 11), and the matching function had to
714            back up over a mixture of the two cases, it incorrectly assumed they
715            were both the same length.
717        (b) When PCRE was configured to use the heap rather than the stack for
718            recursion during matching, it was not correctly preserving the data for
719            the other case of a UTF-8 character when checking ahead for a match
720            while processing a minimizing repeat. If the check also involved
721            matching a wide character, but failed, corruption could cause an
722            erroneous result when trying to check for a repeat of the original
723            character.
725    13. Some tidying changes to the testing mechanism:
727        (a) The RunTest script now detects the internal link size and whether there
728            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
729            values substituted by "configure". (The RunGrepTest script already did
730            this for UTF-8.) The configure.ac script no longer substitutes the
731            relevant variables.
733        (b) The debugging options /B and /D in pcretest show the compiled bytecode
734            with length and offset values. This means that the output is different
735            for different internal link sizes. Test 2 is skipped for link sizes
736            other than 2 because of this, bypassing the problem. Unfortunately,
737            there was also a test in test 3 (the locale tests) that used /B and
738            failed for link sizes other than 2. Rather than cut the whole test out,
739            I have added a new /Z option to pcretest that replaces the length and
740            offset values with spaces. This is now used to make test 3 independent
741            of link size. (Test 2 will be tidied up later.)
743    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
744        segmentation fault instead of returning the appropriate error message.
746    15. In multiline mode when the newline sequence was set to "any", the pattern
747        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
748        This doesn't seem right; it now treats the CRLF combination as the line
749        ending, and so does not match in that case. It's only a pattern such as ^$
750        that would hit this one: something like ^ABC$ would have failed after \r
751        and then tried again after \r\n.
753    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
754        in an attempt to make files that differ only in their line terminators
755        compare equal. This works on Linux.
757    17. Under certain error circumstances pcregrep might try to free random memory
758        as it exited. This is now fixed, thanks to valgrind.
760    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
761        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
762        was because its rules for how to advance for /g after matching an empty
763        string at the end of a line did not allow for this case. They now check for
764        it specially.
766    20. pcretest is supposed to handle patterns and data of any length, by
767        extending its buffers when necessary. It was getting this wrong when the
768        buffer for a data line had to be extended.
770    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
771        CRLF as a newline sequence.
773    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
774        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
775        I have nevertheless tidied it up.
777    23. Added some casts to kill warnings from HP-UX ia64 compiler.
779    24. Added a man page for pcre-config.
782    Version 7.0 19-Dec-06
783    ---------------------
785     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
786        moving to gcc 4.1.1.
788     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
789        sys/time.h, which is documented as needed for this function. It doesn't
790        seem to matter on Linux, but it showed up on some releases of OS X.
792     3. It seems that there are systems where bytes whose values are greater than
793        127 match isprint() in the "C" locale. The "C" locale should be the
794        default when a C program starts up. In most systems, only ASCII printing
795        characters match isprint(). This difference caused the output from pcretest
796        to vary, making some of the tests fail. I have changed pcretest so that:
798        (a) When it is outputting text in the compiled version of a pattern, bytes
799            other than 32-126 are always shown as hex escapes.
801        (b) When it is outputting text that is a matched part of a subject string,
802            it does the same, unless a different locale has been set for the match
803            (using the /L modifier). In this case, it uses isprint() to decide.
805     4. Fixed a major bug that caused incorrect computation of the amount of memory
806        required for a compiled pattern when options that changed within the
807        pattern affected the logic of the preliminary scan that determines the
808        length. The relevant options are -x, and -i in UTF-8 mode. The result was
809        that the computed length was too small. The symptoms of this bug were
810        either the PCRE error "internal error: code overflow" from pcre_compile(),
811        or a glibc crash with a message such as "pcretest: free(): invalid next
812        size (fast)". Examples of patterns that provoked this bug (shown in
813        pcretest format) are:
815          /(?-x: )/x
816          /(?x)(?-x: \s*#\s*)/
817          /((?i)[\x{c0}])/8
818          /(?i:[\x{c0}])/8
820        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
821        is now done differently.
823     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
824        wrapper classes; (b) implement a new function in the C++ scanner that is
825        more efficient than the old way of doing things because it avoids levels of
826        recursion in the regex matching; (c) add a paragraph to the documentation
827        for the FullMatch() function.
829     6. The escape sequence \n was being treated as whatever was defined as
830        "newline". Not only was this contrary to the documentation, which states
831        that \n is character 10 (hex 0A), but it also went horribly wrong when
832        "newline" was defined as CRLF. This has been fixed.
834     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
835        was being set to -1 for the "end of line" case (supposedly a value that no
836        character can have). Though this value is never used (the check for end of
837        line is "zero bytes in current character"), it caused compiler complaints.
838        I've changed it to 0xffffffff.
840     8. In pcre_version.c, the version string was being built by a sequence of
841        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
842        string (as it is for production releases) called a macro with an empty
843        argument. The C standard says the result of this is undefined. The gcc
844        compiler treats it as an empty string (which was what was wanted) but it is
845        reported that Visual C gives an error. The source has been hacked around to
846        avoid this problem.
848     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
849        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
850        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
851        of them did).
853    10. Originally, pcretest opened its input and output without "b"; then I was
854        told that "b" was needed in some environments, so it was added for release
855        5.0 to both the input and output. (It makes no difference on Unix-like
856        systems.) Later I was told that it is wrong for the input on Windows. I've
857        now abstracted the modes into two macros, to make it easier to fiddle with
858        them, and removed "b" from the input mode under Windows.
860    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
862    12. Added -help and --help to pcretest as an official way of being reminded
863        of the options.
865    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
866        and pcrecpp.cc because they annoy compilers at high warning levels.
868    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
870    15. Fixed an occurrence of == in configure.ac that should have been = (shell
871        scripts are not C programs :-) and which was not noticed because it works
872        on Linux.
874    16. pcretest is supposed to handle any length of pattern and data line (as one
875        line or as a continued sequence of lines) by extending its input buffer if
876        necessary. This feature was broken for very long pattern lines, leading to
877        a string of junk being passed to pcre_compile() if the pattern was longer
878        than about 50K.
880    17. I have done a major re-factoring of the way pcre_compile() computes the
881        amount of memory needed for a compiled pattern. Previously, there was code
882        that made a preliminary scan of the pattern in order to do this. That was
883        OK when PCRE was new, but as the facilities have expanded, it has become
884        harder and harder to keep it in step with the real compile phase, and there
885        have been a number of bugs (see for example, 4 above). I have now found a
886        cunning way of running the real compile function in a "fake" mode that
887        enables it to compute how much memory it would need, while actually only
888        ever using a few hundred bytes of working memory and without too many
889        tests of the mode. This should make future maintenance and development
890        easier. A side effect of this work is that the limit of 200 on the nesting
891        depth of parentheses has been removed (though this was never a serious
892        limitation, I suspect). However, there is a downside: pcre_compile() now
893        runs more slowly than before (30% or more, depending on the pattern). I
894        hope this isn't a big issue. There is no effect on runtime performance.
896    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
897        newline (only possible for the last line of a file) and it was a
898        pattern that set a locale (followed by /Lsomething), pcretest crashed.
900    19. Added additional timing features to pcretest. (1) The -tm option now times
901        matching only, not compiling. (2) Both -t and -tm can be followed, as a
902        separate command line item, by a number that specifies the number of
903        repeats to use when timing. The default is 50000; this gives better
904        precision, but takes uncomfortably long for very large patterns.
906    20. Extended pcre_study() to be more clever in cases where a branch of a
907        subpattern has no definite first character. For example, (a*|b*)[cd] would
908        previously give no result from pcre_study(). Now it recognizes that the
909        first character must be a, b, c, or d.
911    21. There was an incorrect error "recursive call could loop indefinitely" if
912        a subpattern (or the entire pattern) that was being tested for matching an
913        empty string contained only one non-empty item after a nested subpattern.
914        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
915        incorrectly, because the \d was being skipped in the check.
917    22. The pcretest program now has a new pattern option /B and a command line
918        option -b, which is equivalent to adding /B to every pattern. This causes
919        it to show the compiled bytecode, without the additional information that
920        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
921        is the same as /B/I).
923    23. A new optimization is now able automatically to treat some sequences such
924        as a*b as a*+b. More specifically, if something simple (such as a character
925        or a simple class like \d) has an unlimited quantifier, and is followed by
926        something that cannot possibly match the quantified thing, the quantifier
927        is automatically "possessified".
929    24. A recursive reference to a subpattern whose number was greater than 39
930        went wrong under certain circumstances in UTF-8 mode. This bug could also
931        have affected the operation of pcre_study().
933    25. Realized that a little bit of performance could be had by replacing
934        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
936    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
938    27. Possessive quantifiers such as a++ were previously implemented by turning
939        them into atomic groups such as ($>a+). Now they have their own opcodes,
940        which improves performance. This includes the automatically created ones
941        from 23 above.
943    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
944        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
945        the first matched character to be a colon. This applied both to named and
946        numbered groups.
948    29. The ucpinternal.h header file was missing its idempotency #ifdef.
950    30. I was sent a "project" file called libpcre.a.dev which I understand makes
951        building PCRE on Windows easier, so I have included it in the distribution.
953    31. There is now a check in pcretest against a ridiculously large number being
954        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
955        loop, the loop is abandoned.
957    32. Forward references to subpatterns in conditions such as (?(2)...) where
958        subpattern 2 is defined later cause pcre_compile() to search forwards in
959        the pattern for the relevant set of parentheses. This search went wrong
960        when there were unescaped parentheses in a character class, parentheses
961        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
963    33. "Subroutine" calls and backreferences were previously restricted to
964        referencing subpatterns earlier in the regex. This restriction has now
965        been removed.
967    34. Added a number of extra features that are going to be in Perl 5.10. On the
968        whole, these are just syntactic alternatives for features that PCRE had
969        previously implemented using the Python syntax or my own invention. The
970        other formats are all retained for compatibility.
972        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
973            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
974            also .NET compatible.
976        (b) A recursion or subroutine call to a named group can now be defined as
977            (?&name) as well as (?P>name).
979        (c) A backreference to a named group can now be defined as \k<name> or
980            \k'name' as well as (?P=name). The new forms, as well as being in Perl
981            5.10, are also .NET compatible.
983        (d) A conditional reference to a named group can now use the syntax
984            (?(<name>) or (?('name') as well as (?(name).
986        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
987            groups (named and numbered) that are never evaluated inline, but can be
988            called as "subroutines" from elsewhere. In effect, the DEFINE condition
989            is always false. There may be only one alternative in such a group.
991        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
992            as the simple (?(R). The condition is true only if the most recent
993            recursion is that of the given number or name. It does not search out
994            through the entire recursion stack.
996        (g) The escape \gN or \g{N} has been added, where N is a positive or
997            negative number, specifying an absolute or relative reference.
999    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1000        some "unreachable code" warnings.
1002    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1003        things, this adds five new scripts.
1005    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1006        There were also incompatibilities regarding the handling of \Q..\E inside
1007        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1008        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1010    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1011        matches an empty string, and forcibly breaks the loop. There were bugs in
1012        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1013        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1014        separate and independent bugs (that affected different cases) have been
1015        fixed.
1017    39. Refactored the code to abolish the use of different opcodes for small
1018        capturing bracket numbers. This is a tidy that I avoided doing when I
1019        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1020        The new approach is not only tidier, it makes it possible to reduce the
1021        memory needed to fix the previous bug (38).
1023    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1024        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1025        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1026        mode.
1028    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1029        report.
1031    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1032        copy construction and assignment in the C++ wrapper.
1034    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1035        couple of bugs that could have given wrong results in the "--newline=crlf"
1036        case.
1038    44. Added a number of casts and did some reorganization of signed/unsigned int
1039        variables following suggestions from Dair Grant. Also renamed the variable
1040        "this" as "item" because it is a C++ keyword.
1042    45. Arranged for dftables to add
1044          #include "pcre_internal.h"
1046        to pcre_chartables.c because without it, gcc 4.x may remove the array
1047        definition from the final binary if PCRE is built into a static library and
1048        dead code stripping is activated.
1050    46. For an unanchored pattern, if a match attempt fails at the start of a
1051        newline sequence, and the newline setting is CRLF or ANY, and the next two
1052        characters are CRLF, advance by two characters instead of one.
1055    Version 6.7 04-Jul-06
1056    ---------------------
1058     1. In order to handle tests when input lines are enormously long, pcretest has
1059        been re-factored so that it automatically extends its buffers when
1060        necessary. The code is crude, but this _is_ just a test program. The
1061        default size has been increased from 32K to 50K.
1063     2. The code in pcre_study() was using the value of the re argument before
1064        testing it for NULL. (Of course, in any sensible call of the function, it
1065        won't be NULL.)
1067     3. The memmove() emulation function in pcre_internal.h, which is used on
1068        systems that lack both memmove() and bcopy() - that is, hardly ever -
1069        was missing a "static" storage class specifier.
1071     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1072        containing an extended class (one that cannot be represented by a bitmap
1073        because it contains high-valued characters or Unicode property items, e.g.
1074        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1075        pattern, but PCRE should not loop if you do not (it no longer does).
1076        [Detail: two cases were found: (a) a repeated subpattern containing an
1077        extended class; (b) a recursive reference to a subpattern that followed a
1078        previous extended class. It wasn't skipping over the extended class
1079        correctly when UTF-8 mode was not set.]
1081     5. A negated single-character class was not being recognized as fixed-length
1082        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1083        compile error "lookbehind assertion is not fixed length".
1085     6. The RunPerlTest auxiliary script was showing an unexpected difference
1086        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1087        write a Perl script that can interpret lines of an input file either as
1088        byte characters or as UTF-8, which is what "perltest" was being required to
1089        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1090        can't do is switch easily at run time between having the "use utf8;" pragma
1091        or not. In the end, I fudged it by using the RunPerlTest script to insert
1092        "use utf8;" explicitly for the UTF-8 tests.
1094     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1095        the end of the subject string, contrary to the documentation and to what
1096        Perl does. This was true of both matching functions. Now it matches only at
1097        the start of the subject and immediately after *internal* newlines.
1099     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1100        a pointer to an int instead of a pointer to an unsigned long int. This
1101        caused problems on 64-bit systems.
1103     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1104        instance of the 'standard' template library not being so standard".
1106    10. There was no check on the number of named subpatterns nor the maximum
1107        length of a subpattern name. The product of these values is used to compute
1108        the size of the memory block for a compiled pattern. By supplying a very
1109        long subpattern name and a large number of named subpatterns, the size
1110        computation could be caused to overflow. This is now prevented by limiting
1111        the length of names to 32 characters, and the number of named subpatterns
1112        to 10,000.
1114    11. Subpatterns that are repeated with specific counts have to be replicated in
1115        the compiled pattern. The size of memory for this was computed from the
1116        length of the subpattern and the repeat count. The latter is limited to
1117        65535, but there was no limit on the former, meaning that integer overflow
1118        could in principle occur. The compiled length of a repeated subpattern is
1119        now limited to 30,000 bytes in order to prevent this.
1121    12. Added the optional facility to have named substrings with the same name.
1123    13. Added the ability to use a named substring as a condition, using the
1124        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1125        are numbers (not recommended). Forward references are permitted.
1127    14. Added forward references in named backreferences (if you see what I mean).
1129    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1130        pattern could run off the end of the subject. For example, the pattern
1131        "(?s)(.{1,5})"8 did this with the subject "ab".
1133    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1134        PCRE_CASELESS was set when matching characters that were quantified with ?
1135        or *.
1137    17. A character class other than a single negated character that had a minimum
1138        but no maximum quantifier - for example [ab]{6,} - was not handled
1139        correctly by pce_dfa_exec(). It would match only one character.
1141    18. A valid (though odd) pattern that looked like a POSIX character
1142        class but used an invalid character after [ (for example [[,abc,]]) caused
1143        pcre_compile() to give the error "Failed: internal error: code overflow" or
1144        in some cases to crash with a glibc free() error. This could even happen if
1145        the pattern terminated after [[ but there just happened to be a sequence of
1146        letters, a binary zero, and a closing ] in the memory that followed.
1148    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1149        over the years. Originally (before any Unicode support), just the bottom 8
1150        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1151        output from "man perlunicode" includes this:
1153          The regular expression compiler produces polymorphic opcodes.  That
1154          is, the pattern adapts to the data and automatically switches to
1155          the Unicode character scheme when presented with Unicode data--or
1156          instead uses a traditional byte scheme when presented with byte
1157          data.
1159        Sadly, a wide octal escape does not cause a switch, and in a string with
1160        no other multibyte characters, these octal escapes are treated as before.
1161        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1162        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1163        Unicode string.
1165        I have not perpetrated such confusion in PCRE. Up till now, it took just
1166        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1167        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1168        translate to the appropriate multibyte character.
1170    29. Applied some refactoring to reduce the number of warnings from Microsoft
1171        and Borland compilers. This has included removing the fudge introduced
1172        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1173        a warning about an unused variable.
1175    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1176        characters since release 4.0, because Perl (from release 5.004) does not.
1177        [Or at least, is documented not to: some releases seem to be in conflict
1178        with the documentation.] However, when a pattern was studied with
1179        pcre_study() and all its branches started with \s, PCRE still included VT
1180        as a possible starting character. Of course, this did no harm; it just
1181        caused an unnecessary match attempt.
1183    22. Removed a now-redundant internal flag bit that recorded the fact that case
1184        dependency changed within the pattern. This was once needed for "required
1185        byte" processing, but is no longer used. This recovers a now-scarce options
1186        bit. Also moved the least significant internal flag bit to the most-
1187        significant bit of the word, which was not previously used (hangover from
1188        the days when it was an int rather than a uint) to free up another bit for
1189        the future.
1191    23. Added support for CRLF line endings as well as CR and LF. As well as the
1192        default being selectable at build time, it can now be changed at runtime
1193        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1194        specify that it is scanning data with non-default line endings.
1196    24. Changed the definition of CXXLINK to make it agree with the definition of
1197        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1199    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1200        recursions. This makes a big different to stack usage for some patterns.
1202    26. If a subpattern containing a named recursion or subroutine reference such
1203        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1204        the space required for the compiled pattern went wrong and gave too small a
1205        value. Depending on the environment, this could lead to "Failed: internal
1206        error: code overflow at offset 49" or "glibc detected double free or
1207        corruption" errors.
1209    27. Applied patches from Google (a) to support the new newline modes and (b) to
1210        advance over multibyte UTF-8 characters in GlobalReplace.
1212    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1213        difference for some implementation of PCRE in some Windows version.
1215    29. Added some extra testing facilities to pcretest:
1217        \q<number>   in a data line sets the "match limit" value
1218        \Q<number>   in a data line sets the "match recursion limt" value
1219        -S <number>  sets the stack size, where <number> is in megabytes
1221        The -S option isn't available for Windows.
1224    Version 6.6 06-Feb-06
1225    ---------------------
1227     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1228        in pcreposix.h. I have copied the definition from pcre.h.
1230     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1231        because pcre.h is no longer a built file.
1233     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1234        not normally included in the compiled code.
1237    Version 6.5 01-Feb-06
1238    ---------------------
1240     1. When using the partial match feature with pcre_dfa_exec(), it was not
1241        anchoring the second and subsequent partial matches at the new starting
1242        point. This could lead to incorrect results. For example, with the pattern
1243        /1234/, partially matching against "123" and then "a4" gave a match.
1245     2. Changes to pcregrep:
1247        (a) All non-match returns from pcre_exec() were being treated as failures
1248            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1249            error message is output. Some extra information is given for the
1250            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1251            probably the only errors that are likely to be caused by users (by
1252            specifying a regex that has nested indefinite repeats, for instance).
1253            If there are more than 20 of these errors, pcregrep is abandoned.
1255        (b) A binary zero was treated as data while matching, but terminated the
1256            output line if it was written out. This has been fixed: binary zeroes
1257            are now no different to any other data bytes.
1259        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1260            used to set a locale for matching. The --locale=xxxx long option has
1261            been added (no short equivalent) to specify a locale explicitly on the
1262            pcregrep command, overriding the environment variables.
1264        (d) When -B was used with -n, some line numbers in the output were one less
1265            than they should have been.
1267        (e) Added the -o (--only-matching) option.
1269        (f) If -A or -C was used with -c (count only), some lines of context were
1270            accidentally printed for the final match.
1272        (g) Added the -H (--with-filename) option.
1274        (h) The combination of options -rh failed to suppress file names for files
1275            that were found from directory arguments.
1277        (i) Added the -D (--devices) and -d (--directories) options.
1279        (j) Added the -F (--fixed-strings) option.
1281        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1283        (l) Added the --colo(u)r option.
1285        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1286            is not present by default.
1288     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1289        items such as (?R) or (?1), when the recursion could match a number of
1290        alternatives. If it matched one of the alternatives, but subsequently,
1291        outside the recursion, there was a failure, the code tried to back up into
1292        the recursion. However, because of the way PCRE is implemented, this is not
1293        possible, and the result was an incorrect result from the match.
1295        In order to prevent this happening, the specification of recursion has
1296        been changed so that all such subpatterns are automatically treated as
1297        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1299     4. I had overlooked the fact that, in some locales, there are characters for
1300        which isalpha() is true but neither isupper() nor islower() are true. In
1301        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1302        and ordfeminine) are like this. This affected the treatment of \w and \W
1303        when they appeared in character classes, but not when they appeared outside
1304        a character class. The bit map for "word" characters is now created
1305        separately from the results of isalnum() instead of just taking it from the
1306        upper, lower, and digit maps. (Plus the underscore character, of course.)
1308     5. The above bug also affected the handling of POSIX character classes such as
1309        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1310        permanent tables. Instead, the bit maps for such a class were previously
1311        created as the appropriate unions of the upper, lower, and digit bitmaps.
1312        Now they are created by subtraction from the [[:word:]] class, which has
1313        its own bitmap.
1315     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1316        It is created by subtracting the vertical space characters (\x09, \x0a,
1317        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1318        subtraction was done in the overall bitmap for a character class, meaning
1319        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1320        be recognized. This bug has been fixed.
1322     7. Patches from the folks at Google:
1324          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1325          real life, but is still worth protecting against".
1327          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1328          regular expressions".
1330          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1331          have it.
1333          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1334          "configure" and the latter not, in order to fix a problem somebody had
1335          with compiling the Arg class on HP-UX.
1337          (e) Improve the error-handling of the C++ wrapper a little bit.
1339          (f) New tests for checking recursion limiting.
1341     8. The pcre_memmove() function, which is used only if the environment does not
1342        have a standard memmove() function (and is therefore rarely compiled),
1343        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1344        returning a result (though PCRE never actually uses the result).
1346     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1347        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1348        returned instead of calling malloc() with an overflowing number that would
1349        most likely cause subsequent chaos.
1351    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1353    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1354        with this option is matched, the nmatch and pmatch options of regexec() are
1355        ignored.
1357    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1358        provided in case anyone wants to the the POSIX interface with UTF-8
1359        strings.
1361    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1362        C++ linking (needed for some HP-UX environments).
1364    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1365        (unused parameter) and in the pcre_printint() function (omitted "default"
1366        switch label when the default is to do nothing).
1368    15. Added some code to make it possible, when PCRE is compiled as a C++
1369        library, to replace subject pointers for pcre_exec() with a smart pointer
1370        class, thus making it possible to process discontinuous strings.
1372    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1373        much the same function. They were added by different people who were trying
1374        to make PCRE easy to compile on non-Unix systems. It has been suggested
1375        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1376        for compiling on Windows systems. I have therefore replaced it with
1377        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1378        defaults to "extern" for C or "extern C" for C++, which works fine on
1379        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1380        SCOPE with something explicit in config.h. In addition:
1382        (a) pcreposix.h still had just "extern" instead of either of these macros;
1383            I have replaced it with PCRE_DATA_SCOPE.
1385        (b) Functions such as _pcre_xclass(), which are internal to the library,
1386            but external in the C sense, all had PCRE_EXPORT in their definitions.
1387            This is apparently wrong for the Windows case, so I have removed it.
1388            (It makes no difference on Unix-like systems.)
1390    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1391        of recursive calls to match(). This is different to MATCH_LIMIT because
1392        that limits the total number of calls to match(), not all of which increase
1393        the depth of recursion. Limiting the recursion depth limits the amount of
1394        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1395        when PCRE is compiled, and changed at run time. A patch from Google adds
1396        this functionality to the C++ interface.
1398    18. Changes to the handling of Unicode character properties:
1400        (a) Updated the table to Unicode 4.1.0.
1402        (b) Recognize characters that are not in the table as "Cn" (undefined).
1404        (c) I revised the way the table is implemented to a much improved format
1405            which includes recognition of ranges. It now supports the ranges that
1406            are defined in UnicodeData.txt, and it also amalgamates other
1407            characters into ranges. This has reduced the number of entries in the
1408            table from around 16,000 to around 3,000, thus reducing its size
1409            considerably. I realized I did not need to use a tree structure after
1410            all - a binary chop search is just as efficient. Having reduced the
1411            number of entries, I extended their size from 6 bytes to 8 bytes to
1412            allow for more data.
1414        (d) Added support for Unicode script names via properties such as \p{Han}.
1416    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1417        matching that character.
1419    20. When matching a repeated Unicode property with a minimum greater than zero,
1420        (for example \pL{2,}), PCRE could look past the end of the subject if it
1421        reached it while seeking the minimum number of characters. This could
1422        happen only if some of the characters were more than one byte long, because
1423        there is a check for at least the minimum number of bytes.
1425    21. Refactored the implementation of \p and \P so as to be more general, to
1426        allow for more different types of property in future. This has changed the
1427        compiled form incompatibly. Anybody with saved compiled patterns that use
1428        \p or \P will have to recompile them.
1430    22. Added "Any" and "L&" to the supported property types.
1432    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1433        but give a compile time error if the value is greater than 0xff.
1435    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1436        accidentally not being installed or uninstalled.
1438    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1439        made were to insert the current release number. This seemed silly, because
1440        it made things harder for people building PCRE on systems that don't run
1441        "configure". I have turned pcre.h into a distributed file, no longer built
1442        by "configure", with the version identification directly included. There is
1443        no longer a pcre.h.in file.
1445        However, this change necessitated a change to the pcre-config script as
1446        well. It is built from pcre-config.in, and one of the substitutions was the
1447        release number. I have updated configure.ac so that ./configure now finds
1448        the release number by grepping pcre.h.
1450    26. Added the ability to run the tests under valgrind.
1453    Version 6.4 05-Sep-05
1454    ---------------------
1456     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1457        "--" to be printed when multiple files were scanned, even when none of the
1458        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1459        consider it to be a bug, and have restored the previous behaviour.
1461     2. A couple of code tidies to get rid of compiler warnings.
1463     3. The pcretest program used to cheat by referring to symbols in the library
1464        whose names begin with _pcre_. These are internal symbols that are not
1465        really supposed to be visible externally, and in some environments it is
1466        possible to suppress them. The cheating is now confined to including
1467        certain files from the library's source, which is a bit cleaner.
1469     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1470        file's purpose clearer.
1472     5. Reorganized pcre_ucp_findchar().
1475    Version 6.3 15-Aug-05
1476    ---------------------
1478     1. The file libpcre.pc.in did not have general read permission in the tarball.
1480     2. There were some problems when building without C++ support:
1482        (a) If C++ support was not built, "make install" and "make test" still
1483            tried to test it.
1485        (b) There were problems when the value of CXX was explicitly set. Some
1486            changes have been made to try to fix these, and ...
1488        (c) --disable-cpp can now be used to explicitly disable C++ support.
1490        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1491            backslash in a target when C++ was disabled. This confuses some
1492            versions of "make", apparently. Using an intermediate variable solves
1493            this. (Same for CPP_LOBJ.)
1495     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1496        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1497        necessary on certain architectures.
1499     4. Added a setting of -export-symbols-regex to the link command to remove
1500        those symbols that are exported in the C sense, but actually are local
1501        within the library, and not documented. Their names all begin with
1502        "_pcre_". This is not a perfect job, because (a) we have to except some
1503        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1504        available (and never for static libraries). I have made a note to try to
1505        find a way round (a) in the future.
1508    Version 6.2 01-Aug-05
1509    ---------------------
1511     1. There was no test for integer overflow of quantifier values. A construction
1512        such as {1111111111111111} would give undefined results. What is worse, if
1513        a minimum quantifier for a parenthesized subpattern overflowed and became
1514        negative, the calculation of the memory size went wrong. This could have
1515        led to memory overwriting.
1517     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1519     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1520        operating environments where this matters.
1522     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1523        PCRE options from within the C++ wrapper.
1525     5. Named capturing subpatterns were not being correctly counted when a pattern
1526        was compiled. This caused two problems: (a) If there were more than 100
1527        such subpatterns, the calculation of the memory needed for the whole
1528        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1529        back references of the form \12, where the number was greater than 9, were
1530        not recognized as back references, even though there were sufficient
1531        previous subpatterns.
1533     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1534        versions of gcc, e.g. 2.95.4.
1537  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1538  ---------------------  ---------------------

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