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revision 49 by nigel, Sat Feb 24 21:39:33 2007 UTC revision 333 by ph10, Thu Apr 10 19:55:57 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.7 05-Mar-08
5    ---------------------
7    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
8        a string to a long long, pretend we don't even have a long long." This is
9        done by checking for the strtoq, strtoll, and _strtoi64 functions.
11    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
12        pre-7.6 versions, which defined a global no_arg variable instead of putting
13        it in the RE class. (See also #8 below.)
15    3.  Remove a line of dead code, identified by coverity and reported by Nuno
16        Lopes.
18    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
20        (1) The include/exclude patterns were being applied to the whole pathnames
21            of files, instead of just to the final components.
23        (2) If there was more than one level of directory, the subdirectories were
24            skipped unless they satisfied the include/exclude conditions. This is
25            inconsistent with GNU grep (and could even be seen as contrary to the
26            pcregrep specification - which I improved to make it absolutely clear).
27            The action now is always to scan all levels of directory, and just
28            apply the include/exclude patterns to regular files.
30    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
31        --exclude_dir in the tests to avoid scanning .svn directories.
33    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
34        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
35        doesn't support NULs in patterns.
37    7.  Added some missing "const"s to declarations of static tables in
38        pcre_compile.c and pcre_dfa_exec.c.
40    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
41        caused by fix #2  above. (Subsequently also a second patch to fix the
42        first patch. And a third patch - this was a messy problem.)
44    9.  Applied Craig's patch to remove the use of push_back().
46    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
47        matching function regexec().
49    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
50        which, however, unlike Perl's \g{...}, are subroutine calls, not back
51        references. PCRE supports relative numbers with this syntax (I don't think
52        Oniguruma does).
55    Version 7.6 28-Jan-08
56    ---------------------
58    1.  A character class containing a very large number of characters with
59        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
60        overflow.
62    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
63        HAVE_LONG_LONG is not defined.
65    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
66        bring them up to date and include new features. This patch includes:
68        - Fixed PH's badly added libz and libbz2 support.
69        - Fixed a problem with static linking.
70        - Added pcredemo. [But later removed - see 7 below.]
71        - Fixed dftables problem and added an option.
72        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
73            HAVE_LONG_LONG.
74        - Added readline support for pcretest.
75        - Added an listing of the option settings after cmake has run.
77    4.  A user submitted a patch to Makefile that makes it easy to create
78        "pcre.dll" under mingw when using Configure/Make. I added stuff to
79        Makefile.am that cause it to include this special target, without
80        affecting anything else. Note that the same mingw target plus all
81        the other distribution libraries and programs are now supported
82        when configuring with CMake (see 6 below) instead of with
83        Configure/Make.
85    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
86        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
87        exported in the Windows port". It has not yet been confirmed that the patch
88        solves the problem, but it does no harm.
90    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
91        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
92        with CMake, and also correct the comment about stack recursion.
94    7.  Remove the automatic building of pcredemo from the ./configure system and
95        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
96        of a program that users should build themselves after PCRE is installed, so
97        building it automatically is not really right. What is more, it gave
98        trouble in some build environments.
100    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
103    Version 7.5 10-Jan-08
104    ---------------------
106    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
107        values in parens when parsing an RE using the C++ wrapper."
109    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
110        Characters greater than 255 were excluded from the class instead of being
111        included.
113    3.  The same bug as (2) above applied to negated POSIX classes such as
114        [:^space:].
116    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
117        defined or documented. It seems to have been a typo for PCRE_STATIC, so
118        I have changed it.
120    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
121        first named subpattern) and a construct such as (?&a) would reference the
122        first named subpattern whose name started with "a" (in other words, the
123        length check was missing). Both these problems are fixed. "Subpattern name
124        expected" is now given for (?&) (a zero-length name), and this patch also
125        makes it give the same error for \k'' (previously it complained that that
126        was a reference to a non-existent subpattern).
128    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
129        this is right because (?- can be followed by option settings as well as by
130        digits. I have, however, made the messages clearer.
132    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
133        than the number used in the conditional) now cause a compile-time error.
134        This is actually not compatible with Perl, which accepts such patterns, but
135        treats the conditional as always being FALSE (as PCRE used to), but it
136        seems to me that giving a diagnostic is better.
138    8.  Change "alphameric" to the more common word "alphanumeric" in comments
139        and messages.
141    9.  Fix two occurrences of "backslash" in comments that should have been
142        "backspace".
144    10. Remove two redundant lines of code that can never be obeyed (their function
145        was moved elsewhere).
147    11. The program that makes PCRE's Unicode character property table had a bug
148        which caused it to generate incorrect table entries for sequences of
149        characters that have the same character type, but are in different scripts.
150        It amalgamated them into a single range, with the script of the first of
151        them. In other words, some characters were in the wrong script. There were
152        thirteen such cases, affecting characters in the following ranges:
154          U+002b0 - U+002c1
155          U+0060c - U+0060d
156          U+0061e - U+00612
157          U+0064b - U+0065e
158          U+0074d - U+0076d
159          U+01800 - U+01805
160          U+01d00 - U+01d77
161          U+01d9b - U+01dbf
162          U+0200b - U+0200f
163          U+030fc - U+030fe
164          U+03260 - U+0327f
165          U+0fb46 - U+0fbb1
166          U+10450 - U+1049d
168    12. The -o option (show only the matching part of a line) for pcregrep was not
169        compatible with GNU grep in that, if there was more than one match in a
170        line, it showed only the first of them. It now behaves in the same way as
171        GNU grep.
173    13. If the -o and -v options were combined for pcregrep, it printed a blank
174        line for every non-matching line. GNU grep prints nothing, and pcregrep now
175        does the same. The return code can be used to tell if there were any
176        non-matching lines.
178    14. Added --file-offsets and --line-offsets to pcregrep.
180    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
181        infinitely looping recursion. The bug was that positive lookaheads were not
182        being skipped when checking for a possible empty match (negative lookaheads
183        and both kinds of lookbehind were skipped).
185    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
186        inclusion of <windows.h> to before rather than after the definition of
187        INVALID_FILE_ATTRIBUTES (patch from David Byron).
189    17. Specifying a possessive quantifier with a specific limit for a Unicode
190        character property caused pcre_compile() to compile bad code, which led at
191        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
192        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
193        caused the error; without that there was no problem.
195    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
197    19. Added --enable-pcretest-libreadline.
199    20. In pcrecpp.cc, the variable 'count' was incremented twice in
200        RE::GlobalReplace(). As a result, the number of replacements returned was
201        double what it should be. I removed one of the increments, but Craig sent a
202        later patch that removed the other one (the right fix) and added unit tests
203        that check the return values (which was not done before).
205    21. Several CMake things:
207        (1) Arranged that, when cmake is used on Unix, the libraries end up with
208            the names libpcre and libpcreposix, not just pcre and pcreposix.
210        (2) The above change means that pcretest and pcregrep are now correctly
211            linked with the newly-built libraries, not previously installed ones.
215    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
216        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
217        UTF-8 newline character). The key issue is that the pattern starts .*;
218        this means that the match must be either at the beginning, or after a
219        newline. The bug was in the code for advancing after a failed match and
220        checking that the new position followed a newline. It was not taking
221        account of UTF-8 characters correctly.
223    23. PCRE was behaving differently from Perl in the way it recognized POSIX
224        character classes. PCRE was not treating the sequence [:...:] as a
225        character class unless the ... were all letters. Perl, however, seems to
226        allow any characters between [: and :], though of course it rejects as
227        unknown any "names" that contain non-letters, because all the known class
228        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
229        for example, whereas PCRE did not - it did not recognize a POSIX character
230        class. This seemed a bit dangerous, so the code has been changed to be
231        closer to Perl. The behaviour is not identical to Perl, because PCRE will
232        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
233        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
234        Perl does, and where it didn't before.
236    24. Rewrite so as to remove the single use of %n from pcregrep because in some
237        Windows environments %n is disabled by default.
240    Version 7.4 21-Sep-07
241    ---------------------
243    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
244        means that a class such as [\s] counted as "explicit reference to CR or
245        LF". That isn't really right - the whole point of the change was to try to
246        help when there was an actual mention of one of the two characters. So now
247        the change happens only if \r or \n (or a literal CR or LF) character is
248        encountered.
250    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
251        of both had grown to the point where there were only 3 bits left.
252        Fortunately, there was spare space in the data structure, and so I have
253        moved the internal flags into a new 16-bit field to free up more option
254        bits.
256    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
257        but did not set the internal JCHANGED flag - either of these is enough to
258        control the way the "get" function works - but the PCRE_INFO_JCHANGED
259        facility is supposed to tell if (?J) was ever used, so now (?J) at the
260        start sets both bits.
262    4.  Added options (at build time, compile time, exec time) to change \R from
263        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
265    5.  doc/pcresyntax.html was missing from the distribution.
267    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
268        compatibility, even though it is no longer used.
270    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
271        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
272        windows.h file is present (where different names are used). [This was
273        reversed later after testing - see 16 below.]
275    8.  Changed all #include <config.h> to #include "config.h". There were also
276        some further <pcre.h> cases that I changed to "pcre.h".
278    9.  When pcregrep was used with the --colour option, it missed the line ending
279        sequence off the lines that it output.
281    10. It was pointed out to me that arrays of string pointers cause lots of
282        relocations when a shared library is dynamically loaded. A technique of
283        using a single long string with a table of offsets can drastically reduce
284        these. I have refactored PCRE in four places to do this. The result is
285        dramatic:
287          Originally:                          290
288          After changing UCP table:            187
289          After changing error message table:   43
290          After changing table of "verbs"       36
291          After changing table of Posix names   22
293        Thanks to the folks working on Gregex for glib for this insight.
295    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
296        unicode-properties was also set.
298    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
300    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
301        checked only for CRLF.
303    14. Added casts to pcretest.c to avoid compiler warnings.
305    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
307    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
308        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
309        entirely. This removes changes made in 7 above.
311    17. The CMake files have been updated, and there is now more information about
312        building with CMake in the NON-UNIX-USE document.
315    Version 7.3 28-Aug-07
316    ---------------------
318     1. In the rejigging of the build system that eventually resulted in 7.1, the
319        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
320        brackets there is not right, since it causes compilers to look for an
321        installed pcre.h, not the version that is in the source that is being
322        compiled (which of course may be different). I have changed it back to:
324          #include "pcre.h"
326        I have a vague recollection that the change was concerned with compiling in
327        different directories, but in the new build system, that is taken care of
328        by the VPATH setting the Makefile.
330     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
331        when the subject happened to end in the byte 0x85 (e.g. if the last
332        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
333        characters but of course it shouldn't be taken as a newline when it is part
334        of another character. The bug was that, for an unlimited repeat of . in
335        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
336        characters when looking for a newline.
338     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
340     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
341        in debug output.
343     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
344        long printing in the pcrecpp unittest when running under MinGW.
346     6. ESC_K was left out of the EBCDIC table.
348     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
349        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
350        limit also applies to "virtual nesting" when a pattern is recursive, and in
351        this case 1000 isn't so big. I have been able to remove this limit at the
352        expense of backing off one optimization in certain circumstances. Normally,
353        when pcre_exec() would call its internal match() function recursively and
354        immediately return the result unconditionally, it uses a "tail recursion"
355        feature to save stack. However, when a subpattern that can match an empty
356        string has an unlimited repetition quantifier, it no longer makes this
357        optimization. That gives it a stack frame in which to save the data for
358        checking that an empty string has been matched. Previously this was taken
359        from the 1000-entry workspace that had been reserved. So now there is no
360        explicit limit, but more stack is used.
362     8. Applied Daniel's patches to solve problems with the import/export magic
363        syntax that is required for Windows, and which was going wrong for the
364        pcreposix and pcrecpp parts of the library. These were overlooked when this
365        problem was solved for the main library.
367     9. There were some crude static tests to avoid integer overflow when computing
368        the size of patterns that contain repeated groups with explicit upper
369        limits. As the maximum quantifier is 65535, the maximum group length was
370        set at 30,000 so that the product of these two numbers did not overflow a
371        32-bit integer. However, it turns out that people want to use groups that
372        are longer than 30,000 bytes (though not repeat them that many times).
373        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
374        made it possible to implement the integer overflow checks in a much more
375        dynamic way, which I have now done. The artificial limitation on group
376        length has been removed - we now have only the limit on the total length of
377        the compiled pattern, which depends on the LINK_SIZE setting.
379    10. Fixed a bug in the documentation for get/copy named substring when
380        duplicate names are permitted. If none of the named substrings are set, the
381        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
382        empty string.
384    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
385        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
386        because the ] is interpreted as the first data character and the
387        terminating ] is not found. PCRE has been made compatible with Perl in this
388        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
389        cause memory overwriting.
391    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
392        string has been matched (to stop an infinite loop). It was not recognizing
393        a conditional subpattern that could match an empty string if that
394        subpattern was within another subpattern. For example, it looped when
395        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
396        condition was not nested. This bug has been fixed.
398    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
399        past the start of the subject in the presence of bytes with the top bit
400        set, for example "\x8aBCD".
402    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
403        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
405    14. Optimized (?!) to (*FAIL).
407    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
408        This restricts code points to be within the range 0 to 0x10FFFF, excluding
409        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
410        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
411        does: it's just the validity check that is more restrictive.
413    16. Inserted checks for integer overflows during escape sequence (backslash)
414        processing, and also fixed erroneous offset values for syntax errors during
415        backslash processing.
417    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
418        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
420    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
421        caused an overrun.
423    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
424        something other than just ASCII characters) inside a group that had an
425        unlimited repeat caused a loop at compile time (while checking to see
426        whether the group could match an empty string).
428    20. Debugging a pattern containing \p or \P could cause a crash. For example,
429        [\P{Any}] did so. (Error in the code for printing property names.)
431    21. An orphan \E inside a character class could cause a crash.
433    22. A repeated capturing bracket such as (A)? could cause a wild memory
434        reference during compilation.
436    23. There are several functions in pcre_compile() that scan along a compiled
437        expression for various reasons (e.g. to see if it's fixed length for look
438        behind). There were bugs in these functions when a repeated \p or \P was
439        present in the pattern. These operators have additional parameters compared
440        with \d, etc, and these were not being taken into account when moving along
441        the compiled data. Specifically:
443        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
444            length.
446        (b) An item such as \pL+ within a repeated group could cause crashes or
447            loops.
449        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
450            "reference to non-existent subpattern" error.
452        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
454    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
455        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
457    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
459    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
460        character were causing crashes (broken optimization).
462    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
463        \p or \P) caused a compile-time loop.
465    28. More problems have arisen in unanchored patterns when CRLF is a valid line
466        break. For example, the unstudied pattern [\r\n]A does not match the string
467        "\r\nA" because change 7.0/46 below moves the current point on by two
468        characters after failing to match at the start. However, the pattern \nA
469        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
470        the same is true. There doesn't seem any very clean way out of this, but
471        what I have chosen to do makes the common cases work: PCRE now takes note
472        of whether there can be an explicit match for \r or \n anywhere in the
473        pattern, and if so, 7.0/46 no longer applies. As part of this change,
474        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
475        pattern has explicit CR or LF references.
477    29. Added (*CR) etc for changing newline setting at start of pattern.
480    Version 7.2 19-Jun-07
481    ---------------------
483     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
484        which is apparently normally available under Windows.
486     2. Re-jig the pcregrep tests with different newline settings in an attempt
487        to make them independent of the local environment's newline setting.
489     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
491     4. Some of the "internals" tests were previously cut out when the link size
492        was not 2, because the output contained actual offsets. The recent new
493        "Z" feature of pcretest means that these can be cut out, making the tests
494        usable with all link sizes.
496     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
497        stack recursion. This gives a massive performance boost under BSD, but just
498        a small improvement under Linux. However, it saves one field in the frame
499        in all cases.
501     6. Added more features from the forthcoming Perl 5.10:
503        (a) (?-n) (where n is a string of digits) is a relative subroutine or
504            recursion call. It refers to the nth most recently opened parentheses.
506        (b) (?+n) is also a relative subroutine call; it refers to the nth next
507            to be opened parentheses.
509        (c) Conditions that refer to capturing parentheses can be specified
510            relatively, for example, (?(-2)... or (?(+3)...
512        (d) \K resets the start of the current match so that everything before
513            is not part of it.
515        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
517        (f) \g{name} is another synonym - part of Perl 5.10's unification of
518            reference syntax.
520        (g) (?| introduces a group in which the numbering of parentheses in each
521            alternative starts with the same number.
523        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
525     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
528     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
529        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
530        for detecting groups that can match an empty string.
532     9. A pattern with a very large number of alternatives (more than several
533        hundred) was running out of internal workspace during the pre-compile
534        phase, where pcre_compile() figures out how much memory will be needed. A
535        bit of new cunning has reduced the workspace needed for groups with
536        alternatives. The 1000-alternative test pattern now uses 12 bytes of
537        workspace instead of running out of the 4096 that are available.
539    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
541    11. Applied patch from Google to remove an optimization that didn't quite work.
542        The report of the bug said:
544          pcrecpp::RE("a*").FullMatch("aaa") matches, while
545          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
546          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
548    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
549        it matched the wrong number of bytes.
552    Version 7.1 24-Apr-07
553    ---------------------
555     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
556        that is more "standard", making use of automake and other Autotools. There
557        is some re-arrangement of the files and adjustment of comments consequent
558        on this.
560     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
561        for recursive directory scanning broke on some systems because the files
562        are not scanned in any specific order and on different systems the order
563        was different. A call to "sort" has been inserted into RunGrepTest for the
564        approprate test as a short-term fix. In the longer term there may be an
565        alternative.
567     3. I had an email from Eric Raymond about problems translating some of PCRE's
568        man pages to HTML (despite the fact that I distribute HTML pages, some
569        people do their own conversions for various reasons). The problems
570        concerned the use of low-level troff macros .br and .in. I have therefore
571        removed all such uses from the man pages (some were redundant, some could
572        be replaced by .nf/.fi pairs). The 132html script that I use to generate
573        HTML has been updated to handle .nf/.fi and to complain if it encounters
574        .br or .in.
576     4. Updated comments in configure.ac that get placed in config.h.in and also
577        arranged for config.h to be included in the distribution, with the name
578        config.h.generic, for the benefit of those who have to compile without
579        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
581     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
582        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
583        makevp.bat for the current PCRE, using the additional files
584        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
586     6. A Windows user reported a minor discrepancy with test 2, which turned out
587        to be caused by a trailing space on an input line that had got lost in his
588        copy. The trailing space was an accident, so I've just removed it.
590     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
591        that is needed.
593     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
594        as "const" (a) because they are and (b) because it helps the PHP
595        maintainers who have recently made a script to detect big data structures
596        in the php code that should be moved to the .rodata section. I remembered
597        to update Builducptable as well, so it won't revert if ucptable.h is ever
598        re-created.
600     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
601        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
602        order to be able to cut out the UTF-8 tables in the latter when UTF-8
603        support is not required. This saves 1.5-2K of code, which is important in
604        some applications.
606        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
607        so as not to refer to the tables, even though these functions will never be
608        called when UTF-8 support is disabled. Otherwise there are problems with a
609        shared library.
611    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
613        (a) It was defining its arguments as char * instead of void *.
615        (b) It was assuming that all moves were upwards in memory; this was true
616            a long time ago when I wrote it, but is no longer the case.
618        The emulated memove() is provided for those environments that have neither
619        memmove() nor bcopy(). I didn't think anyone used it these days, but that
620        is clearly not the case, as these two bugs were recently reported.
622    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
623        and Detrail to create the HTML documentation, the .txt form of the man
624        pages, and it removes trailing spaces from listed files. It also creates
625        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
626        case, it wraps all the #defines with #ifndefs. This script should be run
627        before "make dist".
629    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
630        with Unicode property support.
632        (a) For a maximizing quantifier, if the two different cases of the
633            character were of different lengths in their UTF-8 codings (there are
634            some cases like this - I found 11), and the matching function had to
635            back up over a mixture of the two cases, it incorrectly assumed they
636            were both the same length.
638        (b) When PCRE was configured to use the heap rather than the stack for
639            recursion during matching, it was not correctly preserving the data for
640            the other case of a UTF-8 character when checking ahead for a match
641            while processing a minimizing repeat. If the check also involved
642            matching a wide character, but failed, corruption could cause an
643            erroneous result when trying to check for a repeat of the original
644            character.
646    13. Some tidying changes to the testing mechanism:
648        (a) The RunTest script now detects the internal link size and whether there
649            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
650            values substituted by "configure". (The RunGrepTest script already did
651            this for UTF-8.) The configure.ac script no longer substitutes the
652            relevant variables.
654        (b) The debugging options /B and /D in pcretest show the compiled bytecode
655            with length and offset values. This means that the output is different
656            for different internal link sizes. Test 2 is skipped for link sizes
657            other than 2 because of this, bypassing the problem. Unfortunately,
658            there was also a test in test 3 (the locale tests) that used /B and
659            failed for link sizes other than 2. Rather than cut the whole test out,
660            I have added a new /Z option to pcretest that replaces the length and
661            offset values with spaces. This is now used to make test 3 independent
662            of link size. (Test 2 will be tidied up later.)
664    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
665        segmentation fault instead of returning the appropriate error message.
667    15. In multiline mode when the newline sequence was set to "any", the pattern
668        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
669        This doesn't seem right; it now treats the CRLF combination as the line
670        ending, and so does not match in that case. It's only a pattern such as ^$
671        that would hit this one: something like ^ABC$ would have failed after \r
672        and then tried again after \r\n.
674    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
675        in an attempt to make files that differ only in their line terminators
676        compare equal. This works on Linux.
678    17. Under certain error circumstances pcregrep might try to free random memory
679        as it exited. This is now fixed, thanks to valgrind.
681    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
682        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
683        was because its rules for how to advance for /g after matching an empty
684        string at the end of a line did not allow for this case. They now check for
685        it specially.
687    20. pcretest is supposed to handle patterns and data of any length, by
688        extending its buffers when necessary. It was getting this wrong when the
689        buffer for a data line had to be extended.
691    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
692        CRLF as a newline sequence.
694    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
695        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
696        I have nevertheless tidied it up.
698    23. Added some casts to kill warnings from HP-UX ia64 compiler.
700    24. Added a man page for pcre-config.
703    Version 7.0 19-Dec-06
704    ---------------------
706     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
707        moving to gcc 4.1.1.
709     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
710        sys/time.h, which is documented as needed for this function. It doesn't
711        seem to matter on Linux, but it showed up on some releases of OS X.
713     3. It seems that there are systems where bytes whose values are greater than
714        127 match isprint() in the "C" locale. The "C" locale should be the
715        default when a C program starts up. In most systems, only ASCII printing
716        characters match isprint(). This difference caused the output from pcretest
717        to vary, making some of the tests fail. I have changed pcretest so that:
719        (a) When it is outputting text in the compiled version of a pattern, bytes
720            other than 32-126 are always shown as hex escapes.
722        (b) When it is outputting text that is a matched part of a subject string,
723            it does the same, unless a different locale has been set for the match
724            (using the /L modifier). In this case, it uses isprint() to decide.
726     4. Fixed a major bug that caused incorrect computation of the amount of memory
727        required for a compiled pattern when options that changed within the
728        pattern affected the logic of the preliminary scan that determines the
729        length. The relevant options are -x, and -i in UTF-8 mode. The result was
730        that the computed length was too small. The symptoms of this bug were
731        either the PCRE error "internal error: code overflow" from pcre_compile(),
732        or a glibc crash with a message such as "pcretest: free(): invalid next
733        size (fast)". Examples of patterns that provoked this bug (shown in
734        pcretest format) are:
736          /(?-x: )/x
737          /(?x)(?-x: \s*#\s*)/
738          /((?i)[\x{c0}])/8
739          /(?i:[\x{c0}])/8
741        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
742        is now done differently.
744     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
745        wrapper classes; (b) implement a new function in the C++ scanner that is
746        more efficient than the old way of doing things because it avoids levels of
747        recursion in the regex matching; (c) add a paragraph to the documentation
748        for the FullMatch() function.
750     6. The escape sequence \n was being treated as whatever was defined as
751        "newline". Not only was this contrary to the documentation, which states
752        that \n is character 10 (hex 0A), but it also went horribly wrong when
753        "newline" was defined as CRLF. This has been fixed.
755     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
756        was being set to -1 for the "end of line" case (supposedly a value that no
757        character can have). Though this value is never used (the check for end of
758        line is "zero bytes in current character"), it caused compiler complaints.
759        I've changed it to 0xffffffff.
761     8. In pcre_version.c, the version string was being built by a sequence of
762        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
763        string (as it is for production releases) called a macro with an empty
764        argument. The C standard says the result of this is undefined. The gcc
765        compiler treats it as an empty string (which was what was wanted) but it is
766        reported that Visual C gives an error. The source has been hacked around to
767        avoid this problem.
769     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
770        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
771        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
772        of them did).
774    10. Originally, pcretest opened its input and output without "b"; then I was
775        told that "b" was needed in some environments, so it was added for release
776        5.0 to both the input and output. (It makes no difference on Unix-like
777        systems.) Later I was told that it is wrong for the input on Windows. I've
778        now abstracted the modes into two macros, to make it easier to fiddle with
779        them, and removed "b" from the input mode under Windows.
781    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
783    12. Added -help and --help to pcretest as an official way of being reminded
784        of the options.
786    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
787        and pcrecpp.cc because they annoy compilers at high warning levels.
789    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
791    15. Fixed an occurrence of == in configure.ac that should have been = (shell
792        scripts are not C programs :-) and which was not noticed because it works
793        on Linux.
795    16. pcretest is supposed to handle any length of pattern and data line (as one
796        line or as a continued sequence of lines) by extending its input buffer if
797        necessary. This feature was broken for very long pattern lines, leading to
798        a string of junk being passed to pcre_compile() if the pattern was longer
799        than about 50K.
801    17. I have done a major re-factoring of the way pcre_compile() computes the
802        amount of memory needed for a compiled pattern. Previously, there was code
803        that made a preliminary scan of the pattern in order to do this. That was
804        OK when PCRE was new, but as the facilities have expanded, it has become
805        harder and harder to keep it in step with the real compile phase, and there
806        have been a number of bugs (see for example, 4 above). I have now found a
807        cunning way of running the real compile function in a "fake" mode that
808        enables it to compute how much memory it would need, while actually only
809        ever using a few hundred bytes of working memory and without too many
810        tests of the mode. This should make future maintenance and development
811        easier. A side effect of this work is that the limit of 200 on the nesting
812        depth of parentheses has been removed (though this was never a serious
813        limitation, I suspect). However, there is a downside: pcre_compile() now
814        runs more slowly than before (30% or more, depending on the pattern). I
815        hope this isn't a big issue. There is no effect on runtime performance.
817    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
818        newline (only possible for the last line of a file) and it was a
819        pattern that set a locale (followed by /Lsomething), pcretest crashed.
821    19. Added additional timing features to pcretest. (1) The -tm option now times
822        matching only, not compiling. (2) Both -t and -tm can be followed, as a
823        separate command line item, by a number that specifies the number of
824        repeats to use when timing. The default is 50000; this gives better
825        precision, but takes uncomfortably long for very large patterns.
827    20. Extended pcre_study() to be more clever in cases where a branch of a
828        subpattern has no definite first character. For example, (a*|b*)[cd] would
829        previously give no result from pcre_study(). Now it recognizes that the
830        first character must be a, b, c, or d.
832    21. There was an incorrect error "recursive call could loop indefinitely" if
833        a subpattern (or the entire pattern) that was being tested for matching an
834        empty string contained only one non-empty item after a nested subpattern.
835        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
836        incorrectly, because the \d was being skipped in the check.
838    22. The pcretest program now has a new pattern option /B and a command line
839        option -b, which is equivalent to adding /B to every pattern. This causes
840        it to show the compiled bytecode, without the additional information that
841        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
842        is the same as /B/I).
844    23. A new optimization is now able automatically to treat some sequences such
845        as a*b as a*+b. More specifically, if something simple (such as a character
846        or a simple class like \d) has an unlimited quantifier, and is followed by
847        something that cannot possibly match the quantified thing, the quantifier
848        is automatically "possessified".
850    24. A recursive reference to a subpattern whose number was greater than 39
851        went wrong under certain circumstances in UTF-8 mode. This bug could also
852        have affected the operation of pcre_study().
854    25. Realized that a little bit of performance could be had by replacing
855        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
857    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
859    27. Possessive quantifiers such as a++ were previously implemented by turning
860        them into atomic groups such as ($>a+). Now they have their own opcodes,
861        which improves performance. This includes the automatically created ones
862        from 23 above.
864    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
865        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
866        the first matched character to be a colon. This applied both to named and
867        numbered groups.
869    29. The ucpinternal.h header file was missing its idempotency #ifdef.
871    30. I was sent a "project" file called libpcre.a.dev which I understand makes
872        building PCRE on Windows easier, so I have included it in the distribution.
874    31. There is now a check in pcretest against a ridiculously large number being
875        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
876        loop, the loop is abandoned.
878    32. Forward references to subpatterns in conditions such as (?(2)...) where
879        subpattern 2 is defined later cause pcre_compile() to search forwards in
880        the pattern for the relevant set of parentheses. This search went wrong
881        when there were unescaped parentheses in a character class, parentheses
882        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
884    33. "Subroutine" calls and backreferences were previously restricted to
885        referencing subpatterns earlier in the regex. This restriction has now
886        been removed.
888    34. Added a number of extra features that are going to be in Perl 5.10. On the
889        whole, these are just syntactic alternatives for features that PCRE had
890        previously implemented using the Python syntax or my own invention. The
891        other formats are all retained for compatibility.
893        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
894            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
895            also .NET compatible.
897        (b) A recursion or subroutine call to a named group can now be defined as
898            (?&name) as well as (?P>name).
900        (c) A backreference to a named group can now be defined as \k<name> or
901            \k'name' as well as (?P=name). The new forms, as well as being in Perl
902            5.10, are also .NET compatible.
904        (d) A conditional reference to a named group can now use the syntax
905            (?(<name>) or (?('name') as well as (?(name).
907        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
908            groups (named and numbered) that are never evaluated inline, but can be
909            called as "subroutines" from elsewhere. In effect, the DEFINE condition
910            is always false. There may be only one alternative in such a group.
912        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
913            as the simple (?(R). The condition is true only if the most recent
914            recursion is that of the given number or name. It does not search out
915            through the entire recursion stack.
917        (g) The escape \gN or \g{N} has been added, where N is a positive or
918            negative number, specifying an absolute or relative reference.
920    35. Tidied to get rid of some further signed/unsigned compiler warnings and
921        some "unreachable code" warnings.
923    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
924        things, this adds five new scripts.
926    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
927        There were also incompatibilities regarding the handling of \Q..\E inside
928        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
929        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
931    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
932        matches an empty string, and forcibly breaks the loop. There were bugs in
933        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
934        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
935        separate and independent bugs (that affected different cases) have been
936        fixed.
938    39. Refactored the code to abolish the use of different opcodes for small
939        capturing bracket numbers. This is a tidy that I avoided doing when I
940        removed the limit on the number of capturing brackets for 3.5 back in 2001.
941        The new approach is not only tidier, it makes it possible to reduce the
942        memory needed to fix the previous bug (38).
944    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
945        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
946        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
947        mode.
949    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
950        report.
952    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
953        copy construction and assignment in the C++ wrapper.
955    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
956        couple of bugs that could have given wrong results in the "--newline=crlf"
957        case.
959    44. Added a number of casts and did some reorganization of signed/unsigned int
960        variables following suggestions from Dair Grant. Also renamed the variable
961        "this" as "item" because it is a C++ keyword.
963    45. Arranged for dftables to add
965          #include "pcre_internal.h"
967        to pcre_chartables.c because without it, gcc 4.x may remove the array
968        definition from the final binary if PCRE is built into a static library and
969        dead code stripping is activated.
971    46. For an unanchored pattern, if a match attempt fails at the start of a
972        newline sequence, and the newline setting is CRLF or ANY, and the next two
973        characters are CRLF, advance by two characters instead of one.
976    Version 6.7 04-Jul-06
977    ---------------------
979     1. In order to handle tests when input lines are enormously long, pcretest has
980        been re-factored so that it automatically extends its buffers when
981        necessary. The code is crude, but this _is_ just a test program. The
982        default size has been increased from 32K to 50K.
984     2. The code in pcre_study() was using the value of the re argument before
985        testing it for NULL. (Of course, in any sensible call of the function, it
986        won't be NULL.)
988     3. The memmove() emulation function in pcre_internal.h, which is used on
989        systems that lack both memmove() and bcopy() - that is, hardly ever -
990        was missing a "static" storage class specifier.
992     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
993        containing an extended class (one that cannot be represented by a bitmap
994        because it contains high-valued characters or Unicode property items, e.g.
995        [\pZ]). Almost always one would set UTF-8 mode when processing such a
996        pattern, but PCRE should not loop if you do not (it no longer does).
997        [Detail: two cases were found: (a) a repeated subpattern containing an
998        extended class; (b) a recursive reference to a subpattern that followed a
999        previous extended class. It wasn't skipping over the extended class
1000        correctly when UTF-8 mode was not set.]
1002     5. A negated single-character class was not being recognized as fixed-length
1003        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1004        compile error "lookbehind assertion is not fixed length".
1006     6. The RunPerlTest auxiliary script was showing an unexpected difference
1007        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1008        write a Perl script that can interpret lines of an input file either as
1009        byte characters or as UTF-8, which is what "perltest" was being required to
1010        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1011        can't do is switch easily at run time between having the "use utf8;" pragma
1012        or not. In the end, I fudged it by using the RunPerlTest script to insert
1013        "use utf8;" explicitly for the UTF-8 tests.
1015     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1016        the end of the subject string, contrary to the documentation and to what
1017        Perl does. This was true of both matching functions. Now it matches only at
1018        the start of the subject and immediately after *internal* newlines.
1020     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1021        a pointer to an int instead of a pointer to an unsigned long int. This
1022        caused problems on 64-bit systems.
1024     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1025        instance of the 'standard' template library not being so standard".
1027    10. There was no check on the number of named subpatterns nor the maximum
1028        length of a subpattern name. The product of these values is used to compute
1029        the size of the memory block for a compiled pattern. By supplying a very
1030        long subpattern name and a large number of named subpatterns, the size
1031        computation could be caused to overflow. This is now prevented by limiting
1032        the length of names to 32 characters, and the number of named subpatterns
1033        to 10,000.
1035    11. Subpatterns that are repeated with specific counts have to be replicated in
1036        the compiled pattern. The size of memory for this was computed from the
1037        length of the subpattern and the repeat count. The latter is limited to
1038        65535, but there was no limit on the former, meaning that integer overflow
1039        could in principle occur. The compiled length of a repeated subpattern is
1040        now limited to 30,000 bytes in order to prevent this.
1042    12. Added the optional facility to have named substrings with the same name.
1044    13. Added the ability to use a named substring as a condition, using the
1045        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1046        are numbers (not recommended). Forward references are permitted.
1048    14. Added forward references in named backreferences (if you see what I mean).
1050    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1051        pattern could run off the end of the subject. For example, the pattern
1052        "(?s)(.{1,5})"8 did this with the subject "ab".
1054    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1055        PCRE_CASELESS was set when matching characters that were quantified with ?
1056        or *.
1058    17. A character class other than a single negated character that had a minimum
1059        but no maximum quantifier - for example [ab]{6,} - was not handled
1060        correctly by pce_dfa_exec(). It would match only one character.
1062    18. A valid (though odd) pattern that looked like a POSIX character
1063        class but used an invalid character after [ (for example [[,abc,]]) caused
1064        pcre_compile() to give the error "Failed: internal error: code overflow" or
1065        in some cases to crash with a glibc free() error. This could even happen if
1066        the pattern terminated after [[ but there just happened to be a sequence of
1067        letters, a binary zero, and a closing ] in the memory that followed.
1069    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1070        over the years. Originally (before any Unicode support), just the bottom 8
1071        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1072        output from "man perlunicode" includes this:
1074          The regular expression compiler produces polymorphic opcodes.  That
1075          is, the pattern adapts to the data and automatically switches to
1076          the Unicode character scheme when presented with Unicode data--or
1077          instead uses a traditional byte scheme when presented with byte
1078          data.
1080        Sadly, a wide octal escape does not cause a switch, and in a string with
1081        no other multibyte characters, these octal escapes are treated as before.
1082        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1083        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1084        Unicode string.
1086        I have not perpetrated such confusion in PCRE. Up till now, it took just
1087        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1088        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1089        translate to the appropriate multibyte character.
1091    29. Applied some refactoring to reduce the number of warnings from Microsoft
1092        and Borland compilers. This has included removing the fudge introduced
1093        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1094        a warning about an unused variable.
1096    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1097        characters since release 4.0, because Perl (from release 5.004) does not.
1098        [Or at least, is documented not to: some releases seem to be in conflict
1099        with the documentation.] However, when a pattern was studied with
1100        pcre_study() and all its branches started with \s, PCRE still included VT
1101        as a possible starting character. Of course, this did no harm; it just
1102        caused an unnecessary match attempt.
1104    22. Removed a now-redundant internal flag bit that recorded the fact that case
1105        dependency changed within the pattern. This was once needed for "required
1106        byte" processing, but is no longer used. This recovers a now-scarce options
1107        bit. Also moved the least significant internal flag bit to the most-
1108        significant bit of the word, which was not previously used (hangover from
1109        the days when it was an int rather than a uint) to free up another bit for
1110        the future.
1112    23. Added support for CRLF line endings as well as CR and LF. As well as the
1113        default being selectable at build time, it can now be changed at runtime
1114        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1115        specify that it is scanning data with non-default line endings.
1117    24. Changed the definition of CXXLINK to make it agree with the definition of
1118        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1120    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1121        recursions. This makes a big different to stack usage for some patterns.
1123    26. If a subpattern containing a named recursion or subroutine reference such
1124        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1125        the space required for the compiled pattern went wrong and gave too small a
1126        value. Depending on the environment, this could lead to "Failed: internal
1127        error: code overflow at offset 49" or "glibc detected double free or
1128        corruption" errors.
1130    27. Applied patches from Google (a) to support the new newline modes and (b) to
1131        advance over multibyte UTF-8 characters in GlobalReplace.
1133    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1134        difference for some implementation of PCRE in some Windows version.
1136    29. Added some extra testing facilities to pcretest:
1138        \q<number>   in a data line sets the "match limit" value
1139        \Q<number>   in a data line sets the "match recursion limt" value
1140        -S <number>  sets the stack size, where <number> is in megabytes
1142        The -S option isn't available for Windows.
1145    Version 6.6 06-Feb-06
1146    ---------------------
1148     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1149        in pcreposix.h. I have copied the definition from pcre.h.
1151     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1152        because pcre.h is no longer a built file.
1154     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1155        not normally included in the compiled code.
1158    Version 6.5 01-Feb-06
1159    ---------------------
1161     1. When using the partial match feature with pcre_dfa_exec(), it was not
1162        anchoring the second and subsequent partial matches at the new starting
1163        point. This could lead to incorrect results. For example, with the pattern
1164        /1234/, partially matching against "123" and then "a4" gave a match.
1166     2. Changes to pcregrep:
1168        (a) All non-match returns from pcre_exec() were being treated as failures
1169            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1170            error message is output. Some extra information is given for the
1171            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1172            probably the only errors that are likely to be caused by users (by
1173            specifying a regex that has nested indefinite repeats, for instance).
1174            If there are more than 20 of these errors, pcregrep is abandoned.
1176        (b) A binary zero was treated as data while matching, but terminated the
1177            output line if it was written out. This has been fixed: binary zeroes
1178            are now no different to any other data bytes.
1180        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1181            used to set a locale for matching. The --locale=xxxx long option has
1182            been added (no short equivalent) to specify a locale explicitly on the
1183            pcregrep command, overriding the environment variables.
1185        (d) When -B was used with -n, some line numbers in the output were one less
1186            than they should have been.
1188        (e) Added the -o (--only-matching) option.
1190        (f) If -A or -C was used with -c (count only), some lines of context were
1191            accidentally printed for the final match.
1193        (g) Added the -H (--with-filename) option.
1195        (h) The combination of options -rh failed to suppress file names for files
1196            that were found from directory arguments.
1198        (i) Added the -D (--devices) and -d (--directories) options.
1200        (j) Added the -F (--fixed-strings) option.
1202        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1204        (l) Added the --colo(u)r option.
1206        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1207            is not present by default.
1209     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1210        items such as (?R) or (?1), when the recursion could match a number of
1211        alternatives. If it matched one of the alternatives, but subsequently,
1212        outside the recursion, there was a failure, the code tried to back up into
1213        the recursion. However, because of the way PCRE is implemented, this is not
1214        possible, and the result was an incorrect result from the match.
1216        In order to prevent this happening, the specification of recursion has
1217        been changed so that all such subpatterns are automatically treated as
1218        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1220     4. I had overlooked the fact that, in some locales, there are characters for
1221        which isalpha() is true but neither isupper() nor islower() are true. In
1222        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1223        and ordfeminine) are like this. This affected the treatment of \w and \W
1224        when they appeared in character classes, but not when they appeared outside
1225        a character class. The bit map for "word" characters is now created
1226        separately from the results of isalnum() instead of just taking it from the
1227        upper, lower, and digit maps. (Plus the underscore character, of course.)
1229     5. The above bug also affected the handling of POSIX character classes such as
1230        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1231        permanent tables. Instead, the bit maps for such a class were previously
1232        created as the appropriate unions of the upper, lower, and digit bitmaps.
1233        Now they are created by subtraction from the [[:word:]] class, which has
1234        its own bitmap.
1236     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1237        It is created by subtracting the vertical space characters (\x09, \x0a,
1238        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1239        subtraction was done in the overall bitmap for a character class, meaning
1240        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1241        be recognized. This bug has been fixed.
1243     7. Patches from the folks at Google:
1245          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1246          real life, but is still worth protecting against".
1248          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1249          regular expressions".
1251          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1252          have it.
1254          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1255          "configure" and the latter not, in order to fix a problem somebody had
1256          with compiling the Arg class on HP-UX.
1258          (e) Improve the error-handling of the C++ wrapper a little bit.
1260          (f) New tests for checking recursion limiting.
1262     8. The pcre_memmove() function, which is used only if the environment does not
1263        have a standard memmove() function (and is therefore rarely compiled),
1264        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1265        returning a result (though PCRE never actually uses the result).
1267     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1268        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1269        returned instead of calling malloc() with an overflowing number that would
1270        most likely cause subsequent chaos.
1272    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1274    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1275        with this option is matched, the nmatch and pmatch options of regexec() are
1276        ignored.
1278    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1279        provided in case anyone wants to the the POSIX interface with UTF-8
1280        strings.
1282    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1283        C++ linking (needed for some HP-UX environments).
1285    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1286        (unused parameter) and in the pcre_printint() function (omitted "default"
1287        switch label when the default is to do nothing).
1289    15. Added some code to make it possible, when PCRE is compiled as a C++
1290        library, to replace subject pointers for pcre_exec() with a smart pointer
1291        class, thus making it possible to process discontinuous strings.
1293    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1294        much the same function. They were added by different people who were trying
1295        to make PCRE easy to compile on non-Unix systems. It has been suggested
1296        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1297        for compiling on Windows systems. I have therefore replaced it with
1298        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1299        defaults to "extern" for C or "extern C" for C++, which works fine on
1300        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1301        SCOPE with something explicit in config.h. In addition:
1303        (a) pcreposix.h still had just "extern" instead of either of these macros;
1304            I have replaced it with PCRE_DATA_SCOPE.
1306        (b) Functions such as _pcre_xclass(), which are internal to the library,
1307            but external in the C sense, all had PCRE_EXPORT in their definitions.
1308            This is apparently wrong for the Windows case, so I have removed it.
1309            (It makes no difference on Unix-like systems.)
1311    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1312        of recursive calls to match(). This is different to MATCH_LIMIT because
1313        that limits the total number of calls to match(), not all of which increase
1314        the depth of recursion. Limiting the recursion depth limits the amount of
1315        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1316        when PCRE is compiled, and changed at run time. A patch from Google adds
1317        this functionality to the C++ interface.
1319    18. Changes to the handling of Unicode character properties:
1321        (a) Updated the table to Unicode 4.1.0.
1323        (b) Recognize characters that are not in the table as "Cn" (undefined).
1325        (c) I revised the way the table is implemented to a much improved format
1326            which includes recognition of ranges. It now supports the ranges that
1327            are defined in UnicodeData.txt, and it also amalgamates other
1328            characters into ranges. This has reduced the number of entries in the
1329            table from around 16,000 to around 3,000, thus reducing its size
1330            considerably. I realized I did not need to use a tree structure after
1331            all - a binary chop search is just as efficient. Having reduced the
1332            number of entries, I extended their size from 6 bytes to 8 bytes to
1333            allow for more data.
1335        (d) Added support for Unicode script names via properties such as \p{Han}.
1337    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1338        matching that character.
1340    20. When matching a repeated Unicode property with a minimum greater than zero,
1341        (for example \pL{2,}), PCRE could look past the end of the subject if it
1342        reached it while seeking the minimum number of characters. This could
1343        happen only if some of the characters were more than one byte long, because
1344        there is a check for at least the minimum number of bytes.
1346    21. Refactored the implementation of \p and \P so as to be more general, to
1347        allow for more different types of property in future. This has changed the
1348        compiled form incompatibly. Anybody with saved compiled patterns that use
1349        \p or \P will have to recompile them.
1351    22. Added "Any" and "L&" to the supported property types.
1353    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1354        but give a compile time error if the value is greater than 0xff.
1356    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1357        accidentally not being installed or uninstalled.
1359    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1360        made were to insert the current release number. This seemed silly, because
1361        it made things harder for people building PCRE on systems that don't run
1362        "configure". I have turned pcre.h into a distributed file, no longer built
1363        by "configure", with the version identification directly included. There is
1364        no longer a pcre.h.in file.
1366        However, this change necessitated a change to the pcre-config script as
1367        well. It is built from pcre-config.in, and one of the substitutions was the
1368        release number. I have updated configure.ac so that ./configure now finds
1369        the release number by grepping pcre.h.
1371    26. Added the ability to run the tests under valgrind.
1374    Version 6.4 05-Sep-05
1375    ---------------------
1377     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1378        "--" to be printed when multiple files were scanned, even when none of the
1379        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1380        consider it to be a bug, and have restored the previous behaviour.
1382     2. A couple of code tidies to get rid of compiler warnings.
1384     3. The pcretest program used to cheat by referring to symbols in the library
1385        whose names begin with _pcre_. These are internal symbols that are not
1386        really supposed to be visible externally, and in some environments it is
1387        possible to suppress them. The cheating is now confined to including
1388        certain files from the library's source, which is a bit cleaner.
1390     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1391        file's purpose clearer.
1393     5. Reorganized pcre_ucp_findchar().
1396    Version 6.3 15-Aug-05
1397    ---------------------
1399     1. The file libpcre.pc.in did not have general read permission in the tarball.
1401     2. There were some problems when building without C++ support:
1403        (a) If C++ support was not built, "make install" and "make test" still
1404            tried to test it.
1406        (b) There were problems when the value of CXX was explicitly set. Some
1407            changes have been made to try to fix these, and ...
1409        (c) --disable-cpp can now be used to explicitly disable C++ support.
1411        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1412            backslash in a target when C++ was disabled. This confuses some
1413            versions of "make", apparently. Using an intermediate variable solves
1414            this. (Same for CPP_LOBJ.)
1416     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1417        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1418        necessary on certain architectures.
1420     4. Added a setting of -export-symbols-regex to the link command to remove
1421        those symbols that are exported in the C sense, but actually are local
1422        within the library, and not documented. Their names all begin with
1423        "_pcre_". This is not a perfect job, because (a) we have to except some
1424        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1425        available (and never for static libraries). I have made a note to try to
1426        find a way round (a) in the future.
1429    Version 6.2 01-Aug-05
1430    ---------------------
1432     1. There was no test for integer overflow of quantifier values. A construction
1433        such as {1111111111111111} would give undefined results. What is worse, if
1434        a minimum quantifier for a parenthesized subpattern overflowed and became
1435        negative, the calculation of the memory size went wrong. This could have
1436        led to memory overwriting.
1438     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1440     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1441        operating environments where this matters.
1443     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1444        PCRE options from within the C++ wrapper.
1446     5. Named capturing subpatterns were not being correctly counted when a pattern
1447        was compiled. This caused two problems: (a) If there were more than 100
1448        such subpatterns, the calculation of the memory needed for the whole
1449        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1450        back references of the form \12, where the number was greater than 9, were
1451        not recognized as back references, even though there were sufficient
1452        previous subpatterns.
1454     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1455        versions of gcc, e.g. 2.95.4.
1458    Version 6.1 21-Jun-05
1459    ---------------------
1461     1. There was one reference to the variable "posix" in pcretest.c that was not
1462        surrounded by "#if !defined NOPOSIX".
1464     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1465        the cross-check on the old pcre_info() function, for the benefit of the
1466        cut-down version of PCRE that is currently imported into Exim.
1468     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1469        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1470        patterns that start (?i) but I don't think that matters. The use of (?i) is
1471        just an example; this all applies to the other options as well.
1473     4. Since libtool seems to echo the compile commands it is issuing, the output
1474        from "make" can be reduced a bit by putting "@" in front of each libtool
1475        compile command.
1477     5. Patch from the folks at Google for configure.in to be a bit more thorough
1478        in checking for a suitable C++ installation before trying to compile the
1479        C++ stuff. This should fix a reported problem when a compiler was present,
1480        but no suitable headers.
1482     6. The man pages all had just "PCRE" as their title. I have changed them to
1483        be the relevant file name. I have also arranged that these names are
1484        retained in the file doc/pcre.txt, which is a concatenation in text format
1485        of all the man pages except the little individual ones for each function.
1487     7. The NON-UNIX-USE file had not been updated for the different set of source
1488        files that come with release 6. I also added a few comments about the C++
1489        wrapper.
1492    Version 6.0 07-Jun-05
1493    ---------------------
1495     1. Some minor internal re-organization to help with my DFA experiments.
1497     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1498        didn't matter for the library itself when fully configured, but did matter
1499        when compiling without UCP support, or within Exim, where the ucp files are
1500        not imported.
1502     3. Refactoring of the library code to split up the various functions into
1503        different source modules. The addition of the new DFA matching code (see
1504        below) to a single monolithic source would have made it really too
1505        unwieldy, quite apart from causing all the code to be include in a
1506        statically linked application, when only some functions are used. This is
1507        relevant even without the DFA addition now that patterns can be compiled in
1508        one application and matched in another.
1510        The downside of splitting up is that there have to be some external
1511        functions and data tables that are used internally in different modules of
1512        the library but which are not part of the API. These have all had their
1513        names changed to start with "_pcre_" so that they are unlikely to clash
1514        with other external names.
1516     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1517        a different (DFA) algorithm. Although it is slower than the original
1518        function, it does have some advantages for certain types of matching
1519        problem.
1521     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1522        including restarting after a partial match.
1524     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1525        defined when compiling for Windows was sent to me. I have put it into the
1526        code, though I have no means of testing or verifying it.
1528     7. Added the pcre_refcount() auxiliary function.
1530     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1531        match before or at the first newline in the subject string. In pcretest,
1532        the /f option on a pattern can be used to set this.
1534     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1535        would behave wrongly. This has been present in PCRE since release 4.0.
1537    10. A number of changes to the pcregrep command:
1539        (a) Refactored how -x works; insert ^(...)$ instead of setting
1540            PCRE_ANCHORED and checking the length, in preparation for adding
1541            something similar for -w.
1543        (b) Added the -w (match as a word) option.
1545        (c) Refactored the way lines are read and buffered so as to have more
1546            than one at a time available.
1548        (d) Implemented a pcregrep test script.
1550        (e) Added the -M (multiline match) option. This allows patterns to match
1551            over several lines of the subject. The buffering ensures that at least
1552            8K, or the rest of the document (whichever is the shorter) is available
1553            for matching (and similarly the previous 8K for lookbehind assertions).
1555        (f) Changed the --help output so that it now says
1557              -w, --word-regex(p)
1559            instead of two lines, one with "regex" and the other with "regexp"
1560            because that confused at least one person since the short forms are the
1561            same. (This required a bit of code, as the output is generated
1562            automatically from a table. It wasn't just a text change.)
1564        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1565            option but starts with a hyphen. Could be a pattern or a path name
1566            starting with a hyphen, for instance.
1568        (h) "-" can be given as a file name to represent stdin.
1570        (i) When file names are being printed, "(standard input)" is used for
1571            the standard input, for compatibility with GNU grep. Previously
1572            "<stdin>" was used.
1574        (j) The option --label=xxx can be used to supply a name to be used for
1575            stdin when file names are being printed. There is no short form.
1577        (k) Re-factored the options decoding logic because we are going to add
1578            two more options that take data. Such options can now be given in four
1579            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1581        (l) Added the -A, -B, and -C options for requesting that lines of context
1582            around matches be printed.
1584        (m) Added the -L option to print the names of files that do not contain
1585            any matching lines, that is, the complement of -l.
1587        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1588            continue to scan other files.
1590        (o) The -s option was incorrectly implemented. For compatibility with other
1591            greps, it now suppresses the error message for a non-existent or non-
1592            accessible file (but not the return code). There is a new option called
1593            -q that suppresses the output of matching lines, which was what -s was
1594            previously doing.
1596        (p) Added --include and --exclude options to specify files for inclusion
1597            and exclusion when recursing.
1599    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1600        Hopefully, it now does.
1602    12. Missing cast in pcre_study().
1604    13. Added an "uninstall" target to the makefile.
1606    14. Replaced "extern" in the function prototypes in Makefile.in with
1607        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1608        world, but is set differently for Windows.
1610    15. Added a second compiling function called pcre_compile2(). The only
1611        difference is that it has an extra argument, which is a pointer to an
1612        integer error code. When there is a compile-time failure, this is set
1613        non-zero, in addition to the error test pointer being set to point to an
1614        error message. The new argument may be NULL if no error number is required
1615        (but then you may as well call pcre_compile(), which is now just a
1616        wrapper). This facility is provided because some applications need a
1617        numeric error indication, but it has also enabled me to tidy up the way
1618        compile-time errors are handled in the POSIX wrapper.
1620    16. Added VPATH=.libs to the makefile; this should help when building with one
1621        prefix path and installing with another. (Or so I'm told by someone who
1622        knows more about this stuff than I do.)
1624    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1625        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1626        match everything, including newlines. This is not POSIX-compatible, but
1627        somebody wanted the feature. From pcretest it can be activated by using
1628        both the P and the s flags.
1630    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1632    19. libpcre.pc was being incorrectly installed as executable.
1634    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1635        it now also looks for '\r' so that it will work unmodified on Windows.
1637    21. Added Google's contributed C++ wrapper to the distribution.
1639    22. Added some untidy missing memory free() calls in pcretest, to keep
1640        Electric Fence happy when testing.
1644    Version 5.0 13-Sep-04
1645    ---------------------
1647     1. Internal change: literal characters are no longer packed up into items
1648        containing multiple characters in a single byte-string. Each character
1649        is now matched using a separate opcode. However, there may be more than one
1650        byte in the character in UTF-8 mode.
1652     2. The pcre_callout_block structure has two new fields: pattern_position and
1653        next_item_length. These contain the offset in the pattern to the next match
1654        item, and its length, respectively.
1656     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1657        insertion of callouts before each pattern item. Added the /C option to
1658        pcretest to make use of this.
1660     4. On the advice of a Windows user, the lines
1662          #if defined(_WIN32) || defined(WIN32)
1663          _setmode( _fileno( stdout ), 0x8000 );
1664          #endif  /* defined(_WIN32) || defined(WIN32) */
1666        have been added to the source of pcretest. This apparently does useful
1667        magic in relation to line terminators.
1669     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1670        for the benefit of those environments where the "b" makes a difference.
1672     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1673        to know about it. I have put a hack into configure.in that adds in code
1674        to set GCC=yes if CC=icc. This seems to end up at a point in the
1675        generated configure script that is early enough to affect the setting of
1676        compiler options, which is what is needed, but I have no means of testing
1677        whether it really works. (The user who reported this had patched the
1678        generated configure script, which of course I cannot do.)
1680        LATER: After change 22 below (new libtool files), the configure script
1681        seems to know about icc (and also ecc). Therefore, I have commented out
1682        this hack in configure.in.
1684     7. Added support for pkg-config (2 patches were sent in).
1686     8. Negated POSIX character classes that used a combination of internal tables
1687        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1688        [[:^ascii]]. Typically, they would match almost any characters. The other
1689        POSIX classes were not broken in this way.
1691     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1692        to find the match, as PCRE was deluded into thinking that the match had to
1693        start at the start point or following a newline. The same bug applied to
1694        patterns with negative forward assertions or any backward assertions
1695        preceding ".*" at the start, unless the pattern required a fixed first
1696        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1698    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1699        starting at the last subject character, bytes beyond the end of the subject
1700        string were read.
1702    11. Renamed the variable "class" as "classbits" to make life easier for C++
1703        users. (Previously there was a macro definition, but it apparently wasn't
1704        enough.)
1706    12. Added the new field "tables" to the extra data so that tables can be passed
1707        in at exec time, or the internal tables can be re-selected. This allows
1708        a compiled regex to be saved and re-used at a later time by a different
1709        program that might have everything at different addresses.
1711    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1712        -R library as well as a -L library.
1714    14. The debugging options of pcretest (-d on the command line or D on a
1715        pattern) showed incorrect output for anything following an extended class
1716        that contained multibyte characters and which was followed by a quantifier.
1718    15. Added optional support for general category Unicode character properties
1719        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1720        support. It adds about 90K to the size of the library. The meanings of the
1721        inbuilt class escapes such as \d and \s have NOT been changed.
1723    16. Updated pcredemo.c to include calls to free() to release the memory for the
1724        compiled pattern.
1726    17. The generated file chartables.c was being created in the source directory
1727        instead of in the building directory. This caused the build to fail if the
1728        source directory was different from the building directory, and was
1729        read-only.
1731    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1732        file. No doubt somebody will tell me if they don't make sense... Also added
1733        Dan Mooney's comments about building on OpenVMS.
1735    19. Added support for partial matching via the PCRE_PARTIAL option for
1736        pcre_exec() and the \P data escape in pcretest.
1738    20. Extended pcretest with 3 new pattern features:
1740        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1741              write the compiled pattern to the file whose name is "rest-of-line".
1742              This is a straight binary dump of the data, with the saved pointer to
1743              the character tables forced to be NULL. The study data, if any, is
1744              written too. After writing, pcretest reads a new pattern.
1746        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1747              compiled pattern from the given file. There must not be any
1748              occurrences of "<" in the file name (pretty unlikely); if there are,
1749              pcretest will instead treat the initial "<" as a pattern delimiter.
1750              After reading in the pattern, pcretest goes on to read data lines as
1751              usual.
1753        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1754              and 16-bit fields in a compiled pattern, to simulate a pattern that
1755              was compiled on a host of opposite endianness.
1757    21. The pcre-exec() function can now cope with patterns that were compiled on
1758        hosts of opposite endianness, with this restriction:
1760          As for any compiled expression that is saved and used later, the tables
1761          pointer field cannot be preserved; the extra_data field in the arguments
1762          to pcre_exec() should be used to pass in a tables address if a value
1763          other than the default internal tables were used at compile time.
1765    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1766        now diagnosed as an error. Previously, most of the time, a negative number
1767        would have been treated as zero, but if in addition "ovector" was passed as
1768        NULL, a crash could occur.
1770    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1771        new versions from the libtool 1.5 distribution (the last one is a copy of
1772        a file called libtool.m4). This seems to have fixed the need to patch
1773        "configure" to support Darwin 1.3 (which I used to do). However, I still
1774        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1775        workstation).
1777    24. Changed the PCRE licence to be the more standard "BSD" licence.
1780    Version 4.5 01-Dec-03
1781    ---------------------
1783     1. There has been some re-arrangement of the code for the match() function so
1784        that it can be compiled in a version that does not call itself recursively.
1785        Instead, it keeps those local variables that need separate instances for
1786        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1787        needs to "recurse". Keeping track of where control must go is done by means
1788        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1789        hide most of the details from the main code, and operates only if
1790        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1791        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1792        operating.
1794        To make it easier for callers to provide specially tailored get/free
1795        functions for this usage, two new functions, pcre_stack_malloc, and
1796        pcre_stack_free, are used. They are always called in strict stacking order,
1797        and the size of block requested is always the same.
1799        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1800        PCRE has been compiled to use the stack or the heap for recursion. The
1801        -C option of pcretest uses this to show which version is compiled.
1803        A new data escape \S, is added to pcretest; it causes the amounts of store
1804        obtained and freed by both kinds of malloc/free at match time to be added
1805        to the output.
1807     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1808        what's available on my current Linux desktop machine.
1810     3. When matching a UTF-8 string, the test for a valid string at the start has
1811        been extended. If start_offset is not zero, PCRE now checks that it points
1812        to a byte that is the start of a UTF-8 character. If not, it returns
1813        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1814        this is necessary because there may be backward assertions in the pattern.
1815        When matching the same subject several times, it may save resources to use
1816        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1818     4. The code for checking the validity of UTF-8 strings has been tightened so
1819        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1820        containing "overlong sequences".
1822     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1823        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1824        should have been "&", but it just so happened that all the cases this let
1825        through by mistake were picked up later in the function.
1827     6. I had used a variable called "isblank" - this is a C99 function, causing
1828        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1830     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1831        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1832        so the version is shown; (c) stop "make test" echoing "./RunTest".
1834     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1836     9. The prototype for memmove() for systems that don't have it was using
1837        size_t, but the inclusion of the header that defines size_t was later. I've
1838        moved the #includes for the C headers earlier to avoid this.
1840    10. Added some adjustments to the code to make it easier to compiler on certain
1841        special systems:
1843          (a) Some "const" qualifiers were missing.
1844          (b) Added the macro EXPORT before all exported functions; by default this
1845              is defined to be empty.
1846          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1847              that it reads its output file name as an argument instead of writing
1848              to the standard output and assuming this can be redirected.
1850    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1851        class containing characters with values greater than 255, PCRE compilation
1852        went into a loop.
1854    12. A recursive reference to a subpattern that was within another subpattern
1855        that had a minimum quantifier of zero caused PCRE to crash. For example,
1856        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1857        recursion. If the recursively-called subpattern itself had a zero repeat,
1858        that was OK.
1860    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1861        buffer into which it was copied (for escape processing) was still set at
1862        1024, so long lines caused crashes.
1864    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1865        "internal error: code overflow...". This applied to any character class
1866        that was followed by a possessive quantifier.
1868    15. Modified the Makefile to add libpcre.la as a prerequisite for
1869        libpcreposix.la because I was told this is needed for a parallel build to
1870        work.
1872    16. If a pattern that contained .* following optional items at the start was
1873        studied, the wrong optimizing data was generated, leading to matching
1874        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1875        matching string must start with a or b or c. The correct conclusion for
1876        this pattern is that a match can start with any character.
1879    Version 4.4 13-Aug-03
1880    ---------------------
1882     1. In UTF-8 mode, a character class containing characters with values between
1883        127 and 255 was not handled correctly if the compiled pattern was studied.
1884        In fixing this, I have also improved the studying algorithm for such
1885        classes (slightly).
1887     2. Three internal functions had redundant arguments passed to them. Removal
1888        might give a very teeny performance improvement.
1890     3. Documentation bug: the value of the capture_top field in a callout is *one
1891        more than* the number of the hightest numbered captured substring.
1893     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1894        in incorrectly linking with a previously installed version. They now link
1895        explicitly with libpcre.la.
1897     5. configure.in no longer needs to recognize Cygwin specially.
1899     6. A problem in pcre.in for Windows platforms is fixed.
1901     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1902        pcretest, it used to include the size of the study block as part of its
1903        output. Unfortunately, the structure contains a field that has a different
1904        size on different hardware architectures. This meant that the tests that
1905        showed this size failed. As the block is currently always of a fixed size,
1906        this information isn't actually particularly useful in pcretest output, so
1907        I have just removed it.
1909     8. Three pre-processor statements accidentally did not start in column 1.
1910        Sadly, there are *still* compilers around that complain, even though
1911        standard C has not required this for well over a decade. Sigh.
1913     9. In pcretest, the code for checking callouts passed small integers in the
1914        callout_data field, which is a void * field. However, some picky compilers
1915        complained about the casts involved for this on 64-bit systems. Now
1916        pcretest passes the address of the small integer instead, which should get
1917        rid of the warnings.
1919    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1920        both compile and run time, and gives an error if an invalid UTF-8 sequence
1921        is found. There is a option for disabling this check in cases where the
1922        string is known to be correct and/or the maximum performance is wanted.
1924    11. In response to a bug report, I changed one line in Makefile.in from
1926            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1927        to
1928            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1930        to look similar to other lines, but I have no way of telling whether this
1931        is the right thing to do, as I do not use Windows. No doubt I'll get told
1932        if it's wrong...
1935    Version 4.3 21-May-03
1936    ---------------------
1938    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1939       Makefile.
1941    2. Some refactoring to improve the quality of the code:
1943       (i)   The utf8_table... variables are now declared "const".
1945       (ii)  The code for \cx, which used the "case flipping" table to upper case
1946             lower case letters, now just substracts 32. This is ASCII-specific,
1947             but the whole concept of \cx is ASCII-specific, so it seems
1948             reasonable.
1950       (iii) PCRE was using its character types table to recognize decimal and
1951             hexadecimal digits in the pattern. This is silly, because it handles
1952             only 0-9, a-f, and A-F, but the character types table is locale-
1953             specific, which means strange things might happen. A private
1954             table is now used for this - though it costs 256 bytes, a table is
1955             much faster than multiple explicit tests. Of course, the standard
1956             character types table is still used for matching digits in subject
1957             strings against \d.
1959       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1960             ending in _t are). So I've renamed it as ESC_tee.
1962    3. The first argument for regexec() in the POSIX wrapper should have been
1963       defined as "const".
1965    4. Changed pcretest to use malloc() for its buffers so that they can be
1966       Electric Fenced for debugging.
1968    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1969       to read one or more bytes before the start of the subject string. Often this
1970       had no effect on PCRE's behaviour, but in some circumstances it could
1971       provoke a segmentation fault.
1973    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1974       to try to read one or more bytes before the start of the subject string.
1976    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1977       UTF-8 support could misbehave in various ways if the subject string
1978       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1979       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1980       back over UTF-8 characters.)
1983    Version 4.2 14-Apr-03
1984    ---------------------
1986    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1988    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1989         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1990         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1991         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1992         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1993           and BUILD_EXEEXT
1994         Note: automatic setting of the BUILD variables is not yet working
1995         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1996           compile-time but not at link-time
1997         [LINK]: use for linking executables only
1998         make different versions for Windows and non-Windows
1999         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2000           libraries
2001         [LINK_FOR_BUILD]: new variable
2002         [OBJEXT]: use throughout
2003         [EXEEXT]: use throughout
2004         <winshared>: new target
2005         <wininstall>: new target
2006         <dftables.o>: use native compiler
2007         <dftables>: use native linker
2008         <install>: handle Windows platform correctly
2009         <clean>: ditto
2010         <check>: ditto
2011         copy DLL to top builddir before testing
2013       As part of these changes, -no-undefined was removed again. This was reported
2014       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2015       in any case.
2017    3. Some tidies to get rid of compiler warnings:
2019       . In the match_data structure, match_limit was an unsigned long int, whereas
2020         match_call_count was an int. I've made them both unsigned long ints.
2022       . In pcretest the fact that a const uschar * doesn't automatically cast to
2023         a void * provoked a warning.
2025       . Turning on some more compiler warnings threw up some "shadow" variables
2026         and a few more missing casts.
2028    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2029       option, a class that contained a single character with a value between 128
2030       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2032    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2033       option, a class that contained several characters, but with at least one
2034       whose value was between 128 and 255 caused PCRE to crash.
2037    Version 4.1 12-Mar-03
2038    ---------------------
2040    1. Compiling with gcc -pedantic found a couple of places where casts were
2041    needed, and a string in dftables.c that was longer than standard compilers are
2042    required to support.
2044    2. Compiling with Sun's compiler found a few more places where the code could
2045    be tidied up in order to avoid warnings.
2047    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2048    first of these names is deprecated in the latest Autoconf in favour of the name
2049    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2050    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2051    analogy I have changed it to CFLAGS_FOR_BUILD.
2053    4. Added -no-undefined to the linking command in the Makefile, because this is
2054    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2055    linking step for the pcreposix library.
2057    5. PCRE was failing to diagnose the case of two named groups with the same
2058    name.
2060    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2061    literal character that is needed in the subject for a match, and scans along to
2062    ensure that it is present before embarking on the full matching process. This
2063    saves time in cases of nested unlimited repeats that are never going to match.
2064    Problem: the scan can take a lot of time if the subject is very long (e.g.
2065    megabytes), thus penalizing straightforward matches. It is now done only if the
2066    amount of subject to be scanned is less than 1000 bytes.
2068    7. A lesser problem with the same optimization is that it was recording the
2069    first character of an anchored pattern as "needed", thus provoking a search
2070    right along the subject, even when the first match of the pattern was going to
2071    fail. The "needed" character is now not set for anchored patterns, unless it
2072    follows something in the pattern that is of non-fixed length. Thus, it still
2073    fulfils its original purpose of finding quick non-matches in cases of nested
2074    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2077    Version 4.0 17-Feb-03
2078    ---------------------
2080    1. If a comment in an extended regex that started immediately after a meta-item
2081    extended to the end of string, PCRE compiled incorrect data. This could lead to
2082    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2084    2. Moved to autoconf 2.53 and libtool 1.4.2.
2086    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2087    the special perltest8 script is no longer needed - all the tests can be run
2088    from a single perltest script.
2090    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2091    by \s. It has now been removed in PCRE. This means it isn't recognized as
2092    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2093    class [:space:] *does* include VT, thereby creating a mess.
2095    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2096    space and tab.
2098    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2099    its new features into the main test script, reducing the number of scripts.
2101    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2102    were backward compatible, and made the (?i) apply to the whole pattern, as if
2103    /i were given. Now it behaves more logically, and applies the option setting
2104    only to what follows. PCRE has been changed to follow suit. However, if it
2105    finds options settings right at the start of the pattern, it extracts them into
2106    the global options, as before. Thus, they show up in the info data.
2108    8. Added support for the \Q...\E escape sequence. Characters in between are
2109    treated as literals. This is slightly different from Perl in that $ and @ are
2110    also handled as literals inside the quotes. In Perl, they will cause variable
2111    interpolation. Note the following examples:
2113        Pattern            PCRE matches      Perl matches
2115        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2116        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2117        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2119    For compatibility with Perl, \Q...\E sequences are recognized inside character
2120    classes as well as outside them.
2122    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2123    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2124    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2125    signed/unsigned warnings.
2127    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2128    option for pcretest, so I've replaced it by a simple function that does just
2129    that job.
2131    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2132    "pcregrep -".
2134    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2135    Java package. This provides some syntactic sugar for simple cases of what my
2136    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2137    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2138    item, you can use this simplified notation. Note that only makes sense with
2139    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2140    greediness, whatever the setting of the PCRE_UNGREEDY option.
2142    13. A change of greediness default within a pattern was not taking effect at
2143    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2144    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2145    was abstracted outside.
2147    14. PCRE now supports the \G assertion. It is true when the current matching
2148    position is at the start point of the match. This differs from \A when the
2149    starting offset is non-zero. Used with the /g option of pcretest (or similar
2150    code), it works in the same way as it does for Perl's /g option. If all
2151    alternatives of a regex begin with \G, the expression is anchored to the start
2152    match position, and the "anchored" flag is set in the compiled expression.
2154    15. Some bugs concerning the handling of certain option changes within patterns
2155    have been fixed. These applied to options other than (?ims). For example,
2156    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2157    been the other way round. Some of this was related to change 7 above.
2159    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2160    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2161    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2162    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2164    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2165    mode. Unlike ".", it always matches newline, whatever the setting of
2166    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2167    assertions. Perl allows it, but it doesn't (in general) work because it can't
2168    calculate the length of the lookbehind. At least, that's the case for Perl
2169    5.8.0 - I've been told they are going to document that it doesn't work in
2170    future.
2172    18. Added an error diagnosis for escapes that PCRE does not support: these are
2173    \L, \l, \N, \P, \p, \U, \u, and \X.
2175    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2176    reading past the end of the pattern in cases such as /[abcd/.
2178    20. PCRE was getting more memory than necessary for patterns with classes that
2179    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2181    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2182    compiling PCRE for use with Virtual Pascal.
2184    22. Small fix to the Makefile to make it work properly if the build is done
2185    outside the source tree.
2187    23. Added a new extension: a condition to go with recursion. If a conditional
2188    subpattern starts with (?(R) the "true" branch is used if recursion has
2189    happened, whereas the "false" branch is used only at the top level.
2191    24. When there was a very long string of literal characters (over 255 bytes
2192    without UTF support, over 250 bytes with UTF support), the computation of how
2193    much memory was required could be incorrect, leading to segfaults or other
2194    strange effects.
2196    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2197    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2198    there was a subsequent back reference to those brackets. This meant that, for
2199    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2200    possible to check for precisely this case. All we can do is abandon the
2201    optimization if .* occurs inside capturing brackets when there are any back
2202    references whatsoever. (See below for a better fix that came later.)
2204    26. The handling of the optimization for finding the first character of a
2205    non-anchored pattern, and for finding a character that is required later in the
2206    match were failing in some cases. This didn't break the matching; it just
2207    failed to optimize when it could. The way this is done has been re-implemented.
2209    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2211    28. Added a new feature that provides some of the functionality that Perl
2212    provides with (?{...}). The facility is termed a "callout". The way it is done
2213    in PCRE is for the caller to provide an optional function, by setting
2214    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2215    global variable. By default it is unset, which disables all calling out. To get
2216    the function called, the regex must include (?C) at appropriate points. This
2217    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2218    This provides a means of identifying different callout points. When PCRE
2219    reaches such a point in the regex, if pcre_callout has been set, the external
2220    function is called. It is provided with data in a structure called
2221    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2222    matching continues; if it returns a non-zero value, the match at the current
2223    point fails. However, backtracking will occur if possible. [This was changed
2224    later and other features added - see item 49 below.]
2226    29. pcretest is upgraded to test the callout functionality. It provides a
2227    callout function that displays information. By default, it shows the start of
2228    the match and the current position in the text. There are some new data escapes
2229    to vary what happens:
2231        \C+         in addition, show current contents of captured substrings
2232        \C-         do not supply a callout function
2233        \C!n        return 1 when callout number n is reached
2234        \C!n!m      return 1 when callout number n is reached for the mth time
2236    30. If pcregrep was called with the -l option and just a single file name, it
2237    output "<stdin>" if a match was found, instead of the file name.
2239    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2240    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2241    pcre_exec(). This saves a malloc/free per call. The default value of
2242    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2243    when configuring.
2245    32. The default maximum size of a compiled pattern is 64K. There have been a
2246    few cases of people hitting this limit. The code now uses macros to handle the
2247    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2248    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2249    configuring. Tests 2 and 5 work only with 2-byte links because they output
2250    debugging information about compiled patterns.
2252    33. Internal code re-arrangements:
2254    (a) Moved the debugging function for printing out a compiled regex into
2255        its own source file (printint.c) and used #include to pull it into
2256        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2257        separate copies.
2259    (b) Defined the list of op-code names for debugging as a macro in
2260        internal.h so that it is next to the definition of the opcodes.
2262    (c) Defined a table of op-code lengths for simpler skipping along compiled
2263        code. This is again a macro in internal.h so that it is next to the
2264        definition of the opcodes.
2266    34. Added support for recursive calls to individual subpatterns, along the
2267    lines of Robin Houston's patch (but implemented somewhat differently).
2269    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2270    allow it to read and process whole directories in Win32. This code was
2271    contributed by Lionel Fourquaux; it has not been tested by me.
2273    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2274    used to name a group. Names consist of alphanumerics and underscores, and must
2275    be unique. Back references use the syntax (?P=name) and recursive calls use
2276    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2277    numbers. The function pcre_fullinfo() can be used after compilation to extract
2278    a name/number map. There are three relevant calls:
2280      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2281      PCRE_INFO_NAMECOUNT            yields the number of entries
2282      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2284    The map is a vector of fixed-size entries. The size of each entry depends on
2285    the length of the longest name used. The first two bytes of each entry are the
2286    group number, most significant byte first. There follows the corresponding
2287    name, zero terminated. The names are in alphabetical order.
2289    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2290    case instead of 255. Making it the same both with and without UTF-8 support
2291    means that the same test output works with both.
2293    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2294    calling malloc() with a zero argument.
2296    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2297    optimization. I've improved things by keeping a bitmap of backreferences with
2298    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2299    fact referenced, the optimization can be applied. It is unlikely that a
2300    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2301    the match to follow \n) will appear inside brackets with a number greater than
2302    31, but if it does, any back reference > 31 suppresses the optimization.
2304    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2305    of disabling numbered capturing parentheses. Any opening parenthesis that is
2306    not followed by ? behaves as if it were followed by ?: but named parentheses
2307    can still be used for capturing (and they will acquire numbers in the usual
2308    way).
2310    41. Redesigned the return codes from the match() function into yes/no/error so
2311    that errors can be passed back from deep inside the nested calls. A malloc
2312    failure while inside a recursive subpattern call now causes the
2313    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2315    42. It is now possible to set a limit on the number of times the match()
2316    function is called in a call to pcre_exec(). This facility makes it possible to
2317    limit the amount of recursion and backtracking, though not in a directly
2318    obvious way, because the match() function is used in a number of different
2319    circumstances. The count starts from zero for each position in the subject
2320    string (for non-anchored patterns). The default limit is, for compatibility, a
2321    large number, namely 10 000 000. You can change this in two ways:
2323    (a) When configuring PCRE before making, you can use --with-match-limit=n
2324        to set a default value for the compiled library.
2326    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2327        a different value is set. See 45 below.
2329    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2331    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2332    of things that can be changed at compile time. The first argument specifies
2333    what is wanted and the second points to where the information is to be placed.
2334    The current list of available information is:
2336      PCRE_CONFIG_UTF8
2338    The output is an integer that is set to one if UTF-8 support is available;
2339    otherwise it is set to zero.
2343    The output is an integer that it set to the value of the code that is used for
2344    newline. It is either LF (10) or CR (13).
2348    The output is an integer that contains the number of bytes used for internal
2349    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2353    The output is an integer that contains the threshold above which the POSIX
2354    interface uses malloc() for output vectors. See item 31 above.
2358    The output is an unsigned integer that contains the default limit of the number
2359    of match() calls in a pcre_exec() execution. See 42 above.
2361    44. pcretest has been upgraded by the addition of the -C option. This causes it
2362    to extract all the available output from the new pcre_config() function, and to
2363    output it. The program then exits immediately.
2365    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2366    order to support additional features. One way would have been to define
2367    pcre_exec2() (for example) with extra arguments, but this would not have been
2368    extensible, and would also have required all calls to the original function to
2369    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2370    is used for passing in "extra" data from pcre_study().
2372    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2373    contains the following fields:
2375      flags         a bitmap indicating which of the following fields are set
2376      study_data    opaque data from pcre_study()
2377      match_limit   a way of specifying a limit on match() calls for a specific
2378                      call to pcre_exec()
2379      callout_data  data for callouts (see 49 below)
2381    The flag bits are also defined in pcre.h, and are
2387    The pcre_study() function now returns one of these new pcre_extra blocks, with
2388    the actual study data pointed to by the study_data field, and the
2389    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2390    before. That is, this change is entirely upwards-compatible and requires no
2391    change to existing code.
2393    If you want to pass in additional data to pcre_exec(), you can either place it
2394    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2395    block.
2397    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2398    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2399    times with different match limits, until it finds the minimum value needed for
2400    pcre_exec() to complete. The value is then output. This can be instructive; for
2401    most simple matches the number is quite small, but for pathological cases it
2402    gets very large very quickly.
2404    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2405    returns the size of the data block pointed to by the study_data field in a
2406    pcre_extra block, that is, the value that was passed as the argument to
2407    pcre_malloc() when PCRE was getting memory in which to place the information
2408    created by pcre_study(). The fourth argument should point to a size_t variable.
2409    pcretest has been extended so that this information is shown after a successful
2410    pcre_study() call when information about the compiled regex is being displayed.
2412    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2413    because what follows is always an absolute path. (Later: it turns out that this
2414    is more than cosmetic for MinGW, because it doesn't like empty path
2415    components.)
2417    49. Some changes have been made to the callout feature (see 28 above):
2419    (i)  A callout function now has three choices for what it returns:
2421           0  =>  success, carry on matching
2422         > 0  =>  failure at this point, but backtrack if possible
2423         < 0  =>  serious error, return this value from pcre_exec()
2425         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2426         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2427         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2428         use by callout functions. It will never be used by PCRE itself.
2430    (ii) The pcre_extra structure (see 45 above) has a void * field called
2431         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2432         pcre_callout_block structure has a field of the same name. The contents of
2433         the field passed in the pcre_extra structure are passed to the callout
2434         function in the corresponding field in the callout block. This makes it
2435         easier to use the same callout-containing regex from multiple threads. For
2436         testing, the pcretest program has a new data escape
2438           \C*n        pass the number n (may be negative) as callout_data
2440         If the callout function in pcretest receives a non-zero value as
2441         callout_data, it returns that value.
2443    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2444    there were some redundant $(CFLAGS) in commands that are now specified as
2445    $(LINK), which already includes $(CFLAGS).
2447    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2448    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2449    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2450    one-byte characters throughout. Note that case-insensitive matching applies
2451    only to characters whose values are less than 256. PCRE doesn't support the
2452    notion of cases for higher-valued characters.
2454    (i)   A character class whose characters are all within 0-255 is handled as
2455          a bit map, and the map is inverted for negative classes. Previously, a
2456          character > 255 always failed to match such a class; however it should
2457          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2459    (ii)  A negated character class with a single character < 255 is coded as
2460          "not this character" (OP_NOT). This wasn't working properly when the test
2461          character was multibyte, either singly or repeated.
2463    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2464          mode, for example: \x{100}{2,3}.
2466    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2467          singly or repeated) now correctly test multibyte characters. However,
2468          PCRE doesn't recognize any characters with values greater than 255 as
2469          digits, spaces, or word characters. Such characters always match \D, \S,
2470          and \W, and never match \d, \s, or \w.
2472    (v)   Classes may now contain characters and character ranges with values
2473          greater than 255. For example: [ab\x{100}-\x{400}].
2475    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2476          PCRE in UTF-8 mode.
2478    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2479    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2480    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2481    value.)
2483    53. The single man page has become too large. I have therefore split it up into
2484    a number of separate man pages. These also give rise to individual HTML pages;
2485    these are now put in a separate directory, and there is an index.html page that
2486    lists them all. Some hyperlinking between the pages has been installed.
2488    54. Added convenience functions for handling named capturing parentheses.
2490    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2491    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2492    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2493    are faulted.
2495    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2496    calling configure. These values are used when compiling the dftables.c program
2497    which is run to generate the source of the default character tables. They
2498    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2499    you will need to set these values.
2501    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2504    Version 3.9 02-Jan-02
2505    ---------------------
2507    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2509    2. If --disable-static was given, the building process failed when trying to
2510    build pcretest and pcregrep. (For some reason it was using libtool to compile
2511    them, which is not right, as they aren't part of the library.)
2514    Version 3.8 18-Dec-01
2515    ---------------------
2517    1. The experimental UTF-8 code was completely screwed up. It was packing the
2518    bytes in the wrong order. How dumb can you get?
2521    Version 3.7 29-Oct-01
2522    ---------------------
2524    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2525    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2526    this didn't happen under Solaris 8, where I normally test things.
2528    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2529    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2530    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2531    this fix an hour or so after the initial 3.7 release.)
2534    Version 3.6 23-Oct-01
2535    ---------------------
2537    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2538    offsets passed as NULL with zero offset count.
2540    2. The config.guess and config.sub files had not been updated when I moved to
2541    the latest autoconf.
2544    Version 3.5 15-Aug-01
2545    ---------------------
2547    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2548    had been forgotten.
2550    2. By using declared but undefined structures, we can avoid using "void"
2551    definitions in pcre.h while keeping the internal definitions of the structures
2552    private.
2554    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2555    user point of view, this means that both static and shared libraries are built
2556    by default, but this can be individually controlled. More of the work of
2557    handling this static/shared cases is now inside libtool instead of PCRE's make
2558    file.
2560    4. The pcretest utility is now installed along with pcregrep because it is
2561    useful for users (to test regexs) and by doing this, it automatically gets
2562    relinked by libtool. The documentation has been turned into a man page, so
2563    there are now .1, .txt, and .html versions in /doc.
2565    5. Upgrades to pcregrep:
2566       (i)   Added long-form option names like gnu grep.
2567       (ii)  Added --help to list all options with an explanatory phrase.
2568       (iii) Added -r, --recursive to recurse into sub-directories.
2569       (iv)  Added -f, --file to read patterns from a file.
2571    6. pcre_exec() was referring to its "code" argument before testing that
2572    argument for NULL (and giving an error if it was NULL).
2574    7. Upgraded Makefile.in to allow for compiling in a different directory from
2575    the source directory.
2577    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2578    options bits, the pointer it was passed was to an int instead of to an unsigned
2579    long int. This mattered only on 64-bit systems.
2581    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2582    generated) instead of pcre.in, which it its source. Also made the same change
2583    in several of the .c files.
2585    10. A new release of gcc defines printf() as a macro, which broke pcretest
2586    because it had an ifdef in the middle of a string argument for printf(). Fixed
2587    by using separate calls to printf().
2589    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2590    script, to force use of CR or LF instead of \n in the source. On non-Unix
2591    systems, the value can be set in config.h.
2593    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2594    absolute limit. Changed the text of the error message to make this clear, and
2595    likewise updated the man page.
2597    13. The limit of 99 on the number of capturing subpatterns has been removed.
2598    The new limit is 65535, which I hope will not be a "real" limit.
2601    Version 3.4 22-Aug-00
2602    ---------------------
2604    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2606    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2609  Version 3.3 01-Aug-00  Version 3.3 01-Aug-00
2610  ---------------------  ---------------------

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