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revision 69 by nigel, Sat Feb 24 21:40:18 2007 UTC revision 322 by ph10, Wed Mar 5 17:14:08 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.
16    Version 7.6 28-Jan-08
17    ---------------------
19    1.  A character class containing a very large number of characters with
20        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
21        overflow.
23    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
24        HAVE_LONG_LONG is not defined.
26    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
27        bring them up to date and include new features. This patch includes:
29        - Fixed PH's badly added libz and libbz2 support.
30        - Fixed a problem with static linking.
31        - Added pcredemo. [But later removed - see 7 below.]
32        - Fixed dftables problem and added an option.
33        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
34            HAVE_LONG_LONG.
35        - Added readline support for pcretest.
36        - Added an listing of the option settings after cmake has run.
38    4.  A user submitted a patch to Makefile that makes it easy to create
39        "pcre.dll" under mingw when using Configure/Make. I added stuff to
40        Makefile.am that cause it to include this special target, without
41        affecting anything else. Note that the same mingw target plus all
42        the other distribution libraries and programs are now supported
43        when configuring with CMake (see 6 below) instead of with
44        Configure/Make.
46    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
47        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
48        exported in the Windows port". It has not yet been confirmed that the patch
49        solves the problem, but it does no harm.
51    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
52        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
53        with CMake, and also correct the comment about stack recursion.
55    7.  Remove the automatic building of pcredemo from the ./configure system and
56        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
57        of a program that users should build themselves after PCRE is installed, so
58        building it automatically is not really right. What is more, it gave
59        trouble in some build environments.
61    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
64    Version 7.5 10-Jan-08
65    ---------------------
67    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
68        values in parens when parsing an RE using the C++ wrapper."
70    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
71        Characters greater than 255 were excluded from the class instead of being
72        included.
74    3.  The same bug as (2) above applied to negated POSIX classes such as
75        [:^space:].
77    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
78        defined or documented. It seems to have been a typo for PCRE_STATIC, so
79        I have changed it.
81    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
82        first named subpattern) and a construct such as (?&a) would reference the
83        first named subpattern whose name started with "a" (in other words, the
84        length check was missing). Both these problems are fixed. "Subpattern name
85        expected" is now given for (?&) (a zero-length name), and this patch also
86        makes it give the same error for \k'' (previously it complained that that
87        was a reference to a non-existent subpattern).
89    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
90        this is right because (?- can be followed by option settings as well as by
91        digits. I have, however, made the messages clearer.
93    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
94        than the number used in the conditional) now cause a compile-time error.
95        This is actually not compatible with Perl, which accepts such patterns, but
96        treats the conditional as always being FALSE (as PCRE used to), but it
97        seems to me that giving a diagnostic is better.
99    8.  Change "alphameric" to the more common word "alphanumeric" in comments
100        and messages.
102    9.  Fix two occurrences of "backslash" in comments that should have been
103        "backspace".
105    10. Remove two redundant lines of code that can never be obeyed (their function
106        was moved elsewhere).
108    11. The program that makes PCRE's Unicode character property table had a bug
109        which caused it to generate incorrect table entries for sequences of
110        characters that have the same character type, but are in different scripts.
111        It amalgamated them into a single range, with the script of the first of
112        them. In other words, some characters were in the wrong script. There were
113        thirteen such cases, affecting characters in the following ranges:
115          U+002b0 - U+002c1
116          U+0060c - U+0060d
117          U+0061e - U+00612
118          U+0064b - U+0065e
119          U+0074d - U+0076d
120          U+01800 - U+01805
121          U+01d00 - U+01d77
122          U+01d9b - U+01dbf
123          U+0200b - U+0200f
124          U+030fc - U+030fe
125          U+03260 - U+0327f
126          U+0fb46 - U+0fbb1
127          U+10450 - U+1049d
129    12. The -o option (show only the matching part of a line) for pcregrep was not
130        compatible with GNU grep in that, if there was more than one match in a
131        line, it showed only the first of them. It now behaves in the same way as
132        GNU grep.
134    13. If the -o and -v options were combined for pcregrep, it printed a blank
135        line for every non-matching line. GNU grep prints nothing, and pcregrep now
136        does the same. The return code can be used to tell if there were any
137        non-matching lines.
139    14. Added --file-offsets and --line-offsets to pcregrep.
141    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
142        infinitely looping recursion. The bug was that positive lookaheads were not
143        being skipped when checking for a possible empty match (negative lookaheads
144        and both kinds of lookbehind were skipped).
146    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
147        inclusion of <windows.h> to before rather than after the definition of
148        INVALID_FILE_ATTRIBUTES (patch from David Byron).
150    17. Specifying a possessive quantifier with a specific limit for a Unicode
151        character property caused pcre_compile() to compile bad code, which led at
152        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
153        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
154        caused the error; without that there was no problem.
156    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
158    19. Added --enable-pcretest-libreadline.
160    20. In pcrecpp.cc, the variable 'count' was incremented twice in
161        RE::GlobalReplace(). As a result, the number of replacements returned was
162        double what it should be. I removed one of the increments, but Craig sent a
163        later patch that removed the other one (the right fix) and added unit tests
164        that check the return values (which was not done before).
166    21. Several CMake things:
168        (1) Arranged that, when cmake is used on Unix, the libraries end up with
169            the names libpcre and libpcreposix, not just pcre and pcreposix.
171        (2) The above change means that pcretest and pcregrep are now correctly
172            linked with the newly-built libraries, not previously installed ones.
176    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
177        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
178        UTF-8 newline character). The key issue is that the pattern starts .*;
179        this means that the match must be either at the beginning, or after a
180        newline. The bug was in the code for advancing after a failed match and
181        checking that the new position followed a newline. It was not taking
182        account of UTF-8 characters correctly.
184    23. PCRE was behaving differently from Perl in the way it recognized POSIX
185        character classes. PCRE was not treating the sequence [:...:] as a
186        character class unless the ... were all letters. Perl, however, seems to
187        allow any characters between [: and :], though of course it rejects as
188        unknown any "names" that contain non-letters, because all the known class
189        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
190        for example, whereas PCRE did not - it did not recognize a POSIX character
191        class. This seemed a bit dangerous, so the code has been changed to be
192        closer to Perl. The behaviour is not identical to Perl, because PCRE will
193        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
194        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
195        Perl does, and where it didn't before.
197    24. Rewrite so as to remove the single use of %n from pcregrep because in some
198        Windows environments %n is disabled by default.
201    Version 7.4 21-Sep-07
202    ---------------------
204    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
205        means that a class such as [\s] counted as "explicit reference to CR or
206        LF". That isn't really right - the whole point of the change was to try to
207        help when there was an actual mention of one of the two characters. So now
208        the change happens only if \r or \n (or a literal CR or LF) character is
209        encountered.
211    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
212        of both had grown to the point where there were only 3 bits left.
213        Fortunately, there was spare space in the data structure, and so I have
214        moved the internal flags into a new 16-bit field to free up more option
215        bits.
217    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
218        but did not set the internal JCHANGED flag - either of these is enough to
219        control the way the "get" function works - but the PCRE_INFO_JCHANGED
220        facility is supposed to tell if (?J) was ever used, so now (?J) at the
221        start sets both bits.
223    4.  Added options (at build time, compile time, exec time) to change \R from
224        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
226    5.  doc/pcresyntax.html was missing from the distribution.
228    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
229        compatibility, even though it is no longer used.
231    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
232        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
233        windows.h file is present (where different names are used). [This was
234        reversed later after testing - see 16 below.]
236    8.  Changed all #include <config.h> to #include "config.h". There were also
237        some further <pcre.h> cases that I changed to "pcre.h".
239    9.  When pcregrep was used with the --colour option, it missed the line ending
240        sequence off the lines that it output.
242    10. It was pointed out to me that arrays of string pointers cause lots of
243        relocations when a shared library is dynamically loaded. A technique of
244        using a single long string with a table of offsets can drastically reduce
245        these. I have refactored PCRE in four places to do this. The result is
246        dramatic:
248          Originally:                          290
249          After changing UCP table:            187
250          After changing error message table:   43
251          After changing table of "verbs"       36
252          After changing table of Posix names   22
254        Thanks to the folks working on Gregex for glib for this insight.
256    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
257        unicode-properties was also set.
259    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
261    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
262        checked only for CRLF.
264    14. Added casts to pcretest.c to avoid compiler warnings.
266    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
268    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
269        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
270        entirely. This removes changes made in 7 above.
272    17. The CMake files have been updated, and there is now more information about
273        building with CMake in the NON-UNIX-USE document.
276    Version 7.3 28-Aug-07
277    ---------------------
279     1. In the rejigging of the build system that eventually resulted in 7.1, the
280        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
281        brackets there is not right, since it causes compilers to look for an
282        installed pcre.h, not the version that is in the source that is being
283        compiled (which of course may be different). I have changed it back to:
285          #include "pcre.h"
287        I have a vague recollection that the change was concerned with compiling in
288        different directories, but in the new build system, that is taken care of
289        by the VPATH setting the Makefile.
291     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
292        when the subject happened to end in the byte 0x85 (e.g. if the last
293        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
294        characters but of course it shouldn't be taken as a newline when it is part
295        of another character. The bug was that, for an unlimited repeat of . in
296        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
297        characters when looking for a newline.
299     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
301     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
302        in debug output.
304     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
305        long printing in the pcrecpp unittest when running under MinGW.
307     6. ESC_K was left out of the EBCDIC table.
309     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
310        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
311        limit also applies to "virtual nesting" when a pattern is recursive, and in
312        this case 1000 isn't so big. I have been able to remove this limit at the
313        expense of backing off one optimization in certain circumstances. Normally,
314        when pcre_exec() would call its internal match() function recursively and
315        immediately return the result unconditionally, it uses a "tail recursion"
316        feature to save stack. However, when a subpattern that can match an empty
317        string has an unlimited repetition quantifier, it no longer makes this
318        optimization. That gives it a stack frame in which to save the data for
319        checking that an empty string has been matched. Previously this was taken
320        from the 1000-entry workspace that had been reserved. So now there is no
321        explicit limit, but more stack is used.
323     8. Applied Daniel's patches to solve problems with the import/export magic
324        syntax that is required for Windows, and which was going wrong for the
325        pcreposix and pcrecpp parts of the library. These were overlooked when this
326        problem was solved for the main library.
328     9. There were some crude static tests to avoid integer overflow when computing
329        the size of patterns that contain repeated groups with explicit upper
330        limits. As the maximum quantifier is 65535, the maximum group length was
331        set at 30,000 so that the product of these two numbers did not overflow a
332        32-bit integer. However, it turns out that people want to use groups that
333        are longer than 30,000 bytes (though not repeat them that many times).
334        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
335        made it possible to implement the integer overflow checks in a much more
336        dynamic way, which I have now done. The artificial limitation on group
337        length has been removed - we now have only the limit on the total length of
338        the compiled pattern, which depends on the LINK_SIZE setting.
340    10. Fixed a bug in the documentation for get/copy named substring when
341        duplicate names are permitted. If none of the named substrings are set, the
342        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
343        empty string.
345    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
346        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
347        because the ] is interpreted as the first data character and the
348        terminating ] is not found. PCRE has been made compatible with Perl in this
349        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
350        cause memory overwriting.
352    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
353        string has been matched (to stop an infinite loop). It was not recognizing
354        a conditional subpattern that could match an empty string if that
355        subpattern was within another subpattern. For example, it looped when
356        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
357        condition was not nested. This bug has been fixed.
359    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
360        past the start of the subject in the presence of bytes with the top bit
361        set, for example "\x8aBCD".
363    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
364        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
366    14. Optimized (?!) to (*FAIL).
368    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
369        This restricts code points to be within the range 0 to 0x10FFFF, excluding
370        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
371        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
372        does: it's just the validity check that is more restrictive.
374    16. Inserted checks for integer overflows during escape sequence (backslash)
375        processing, and also fixed erroneous offset values for syntax errors during
376        backslash processing.
378    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
379        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
381    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
382        caused an overrun.
384    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
385        something other than just ASCII characters) inside a group that had an
386        unlimited repeat caused a loop at compile time (while checking to see
387        whether the group could match an empty string).
389    20. Debugging a pattern containing \p or \P could cause a crash. For example,
390        [\P{Any}] did so. (Error in the code for printing property names.)
392    21. An orphan \E inside a character class could cause a crash.
394    22. A repeated capturing bracket such as (A)? could cause a wild memory
395        reference during compilation.
397    23. There are several functions in pcre_compile() that scan along a compiled
398        expression for various reasons (e.g. to see if it's fixed length for look
399        behind). There were bugs in these functions when a repeated \p or \P was
400        present in the pattern. These operators have additional parameters compared
401        with \d, etc, and these were not being taken into account when moving along
402        the compiled data. Specifically:
404        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
405            length.
407        (b) An item such as \pL+ within a repeated group could cause crashes or
408            loops.
410        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
411            "reference to non-existent subpattern" error.
413        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
415    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
416        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
418    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
420    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
421        character were causing crashes (broken optimization).
423    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
424        \p or \P) caused a compile-time loop.
426    28. More problems have arisen in unanchored patterns when CRLF is a valid line
427        break. For example, the unstudied pattern [\r\n]A does not match the string
428        "\r\nA" because change 7.0/46 below moves the current point on by two
429        characters after failing to match at the start. However, the pattern \nA
430        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
431        the same is true. There doesn't seem any very clean way out of this, but
432        what I have chosen to do makes the common cases work: PCRE now takes note
433        of whether there can be an explicit match for \r or \n anywhere in the
434        pattern, and if so, 7.0/46 no longer applies. As part of this change,
435        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
436        pattern has explicit CR or LF references.
438    29. Added (*CR) etc for changing newline setting at start of pattern.
441    Version 7.2 19-Jun-07
442    ---------------------
444     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
445        which is apparently normally available under Windows.
447     2. Re-jig the pcregrep tests with different newline settings in an attempt
448        to make them independent of the local environment's newline setting.
450     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
452     4. Some of the "internals" tests were previously cut out when the link size
453        was not 2, because the output contained actual offsets. The recent new
454        "Z" feature of pcretest means that these can be cut out, making the tests
455        usable with all link sizes.
457     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
458        stack recursion. This gives a massive performance boost under BSD, but just
459        a small improvement under Linux. However, it saves one field in the frame
460        in all cases.
462     6. Added more features from the forthcoming Perl 5.10:
464        (a) (?-n) (where n is a string of digits) is a relative subroutine or
465            recursion call. It refers to the nth most recently opened parentheses.
467        (b) (?+n) is also a relative subroutine call; it refers to the nth next
468            to be opened parentheses.
470        (c) Conditions that refer to capturing parentheses can be specified
471            relatively, for example, (?(-2)... or (?(+3)...
473        (d) \K resets the start of the current match so that everything before
474            is not part of it.
476        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
478        (f) \g{name} is another synonym - part of Perl 5.10's unification of
479            reference syntax.
481        (g) (?| introduces a group in which the numbering of parentheses in each
482            alternative starts with the same number.
484        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
486     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
489     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
490        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
491        for detecting groups that can match an empty string.
493     9. A pattern with a very large number of alternatives (more than several
494        hundred) was running out of internal workspace during the pre-compile
495        phase, where pcre_compile() figures out how much memory will be needed. A
496        bit of new cunning has reduced the workspace needed for groups with
497        alternatives. The 1000-alternative test pattern now uses 12 bytes of
498        workspace instead of running out of the 4096 that are available.
500    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
502    11. Applied patch from Google to remove an optimization that didn't quite work.
503        The report of the bug said:
505          pcrecpp::RE("a*").FullMatch("aaa") matches, while
506          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
507          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
509    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
510        it matched the wrong number of bytes.
513    Version 7.1 24-Apr-07
514    ---------------------
516     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
517        that is more "standard", making use of automake and other Autotools. There
518        is some re-arrangement of the files and adjustment of comments consequent
519        on this.
521     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
522        for recursive directory scanning broke on some systems because the files
523        are not scanned in any specific order and on different systems the order
524        was different. A call to "sort" has been inserted into RunGrepTest for the
525        approprate test as a short-term fix. In the longer term there may be an
526        alternative.
528     3. I had an email from Eric Raymond about problems translating some of PCRE's
529        man pages to HTML (despite the fact that I distribute HTML pages, some
530        people do their own conversions for various reasons). The problems
531        concerned the use of low-level troff macros .br and .in. I have therefore
532        removed all such uses from the man pages (some were redundant, some could
533        be replaced by .nf/.fi pairs). The 132html script that I use to generate
534        HTML has been updated to handle .nf/.fi and to complain if it encounters
535        .br or .in.
537     4. Updated comments in configure.ac that get placed in config.h.in and also
538        arranged for config.h to be included in the distribution, with the name
539        config.h.generic, for the benefit of those who have to compile without
540        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
542     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
543        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
544        makevp.bat for the current PCRE, using the additional files
545        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
547     6. A Windows user reported a minor discrepancy with test 2, which turned out
548        to be caused by a trailing space on an input line that had got lost in his
549        copy. The trailing space was an accident, so I've just removed it.
551     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
552        that is needed.
554     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
555        as "const" (a) because they are and (b) because it helps the PHP
556        maintainers who have recently made a script to detect big data structures
557        in the php code that should be moved to the .rodata section. I remembered
558        to update Builducptable as well, so it won't revert if ucptable.h is ever
559        re-created.
561     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
562        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
563        order to be able to cut out the UTF-8 tables in the latter when UTF-8
564        support is not required. This saves 1.5-2K of code, which is important in
565        some applications.
567        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
568        so as not to refer to the tables, even though these functions will never be
569        called when UTF-8 support is disabled. Otherwise there are problems with a
570        shared library.
572    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
574        (a) It was defining its arguments as char * instead of void *.
576        (b) It was assuming that all moves were upwards in memory; this was true
577            a long time ago when I wrote it, but is no longer the case.
579        The emulated memove() is provided for those environments that have neither
580        memmove() nor bcopy(). I didn't think anyone used it these days, but that
581        is clearly not the case, as these two bugs were recently reported.
583    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
584        and Detrail to create the HTML documentation, the .txt form of the man
585        pages, and it removes trailing spaces from listed files. It also creates
586        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
587        case, it wraps all the #defines with #ifndefs. This script should be run
588        before "make dist".
590    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
591        with Unicode property support.
593        (a) For a maximizing quantifier, if the two different cases of the
594            character were of different lengths in their UTF-8 codings (there are
595            some cases like this - I found 11), and the matching function had to
596            back up over a mixture of the two cases, it incorrectly assumed they
597            were both the same length.
599        (b) When PCRE was configured to use the heap rather than the stack for
600            recursion during matching, it was not correctly preserving the data for
601            the other case of a UTF-8 character when checking ahead for a match
602            while processing a minimizing repeat. If the check also involved
603            matching a wide character, but failed, corruption could cause an
604            erroneous result when trying to check for a repeat of the original
605            character.
607    13. Some tidying changes to the testing mechanism:
609        (a) The RunTest script now detects the internal link size and whether there
610            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
611            values substituted by "configure". (The RunGrepTest script already did
612            this for UTF-8.) The configure.ac script no longer substitutes the
613            relevant variables.
615        (b) The debugging options /B and /D in pcretest show the compiled bytecode
616            with length and offset values. This means that the output is different
617            for different internal link sizes. Test 2 is skipped for link sizes
618            other than 2 because of this, bypassing the problem. Unfortunately,
619            there was also a test in test 3 (the locale tests) that used /B and
620            failed for link sizes other than 2. Rather than cut the whole test out,
621            I have added a new /Z option to pcretest that replaces the length and
622            offset values with spaces. This is now used to make test 3 independent
623            of link size. (Test 2 will be tidied up later.)
625    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
626        segmentation fault instead of returning the appropriate error message.
628    15. In multiline mode when the newline sequence was set to "any", the pattern
629        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
630        This doesn't seem right; it now treats the CRLF combination as the line
631        ending, and so does not match in that case. It's only a pattern such as ^$
632        that would hit this one: something like ^ABC$ would have failed after \r
633        and then tried again after \r\n.
635    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
636        in an attempt to make files that differ only in their line terminators
637        compare equal. This works on Linux.
639    17. Under certain error circumstances pcregrep might try to free random memory
640        as it exited. This is now fixed, thanks to valgrind.
642    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
643        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
644        was because its rules for how to advance for /g after matching an empty
645        string at the end of a line did not allow for this case. They now check for
646        it specially.
648    20. pcretest is supposed to handle patterns and data of any length, by
649        extending its buffers when necessary. It was getting this wrong when the
650        buffer for a data line had to be extended.
652    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
653        CRLF as a newline sequence.
655    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
656        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
657        I have nevertheless tidied it up.
659    23. Added some casts to kill warnings from HP-UX ia64 compiler.
661    24. Added a man page for pcre-config.
664    Version 7.0 19-Dec-06
665    ---------------------
667     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
668        moving to gcc 4.1.1.
670     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
671        sys/time.h, which is documented as needed for this function. It doesn't
672        seem to matter on Linux, but it showed up on some releases of OS X.
674     3. It seems that there are systems where bytes whose values are greater than
675        127 match isprint() in the "C" locale. The "C" locale should be the
676        default when a C program starts up. In most systems, only ASCII printing
677        characters match isprint(). This difference caused the output from pcretest
678        to vary, making some of the tests fail. I have changed pcretest so that:
680        (a) When it is outputting text in the compiled version of a pattern, bytes
681            other than 32-126 are always shown as hex escapes.
683        (b) When it is outputting text that is a matched part of a subject string,
684            it does the same, unless a different locale has been set for the match
685            (using the /L modifier). In this case, it uses isprint() to decide.
687     4. Fixed a major bug that caused incorrect computation of the amount of memory
688        required for a compiled pattern when options that changed within the
689        pattern affected the logic of the preliminary scan that determines the
690        length. The relevant options are -x, and -i in UTF-8 mode. The result was
691        that the computed length was too small. The symptoms of this bug were
692        either the PCRE error "internal error: code overflow" from pcre_compile(),
693        or a glibc crash with a message such as "pcretest: free(): invalid next
694        size (fast)". Examples of patterns that provoked this bug (shown in
695        pcretest format) are:
697          /(?-x: )/x
698          /(?x)(?-x: \s*#\s*)/
699          /((?i)[\x{c0}])/8
700          /(?i:[\x{c0}])/8
702        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
703        is now done differently.
705     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
706        wrapper classes; (b) implement a new function in the C++ scanner that is
707        more efficient than the old way of doing things because it avoids levels of
708        recursion in the regex matching; (c) add a paragraph to the documentation
709        for the FullMatch() function.
711     6. The escape sequence \n was being treated as whatever was defined as
712        "newline". Not only was this contrary to the documentation, which states
713        that \n is character 10 (hex 0A), but it also went horribly wrong when
714        "newline" was defined as CRLF. This has been fixed.
716     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
717        was being set to -1 for the "end of line" case (supposedly a value that no
718        character can have). Though this value is never used (the check for end of
719        line is "zero bytes in current character"), it caused compiler complaints.
720        I've changed it to 0xffffffff.
722     8. In pcre_version.c, the version string was being built by a sequence of
723        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
724        string (as it is for production releases) called a macro with an empty
725        argument. The C standard says the result of this is undefined. The gcc
726        compiler treats it as an empty string (which was what was wanted) but it is
727        reported that Visual C gives an error. The source has been hacked around to
728        avoid this problem.
730     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
731        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
732        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
733        of them did).
735    10. Originally, pcretest opened its input and output without "b"; then I was
736        told that "b" was needed in some environments, so it was added for release
737        5.0 to both the input and output. (It makes no difference on Unix-like
738        systems.) Later I was told that it is wrong for the input on Windows. I've
739        now abstracted the modes into two macros, to make it easier to fiddle with
740        them, and removed "b" from the input mode under Windows.
742    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
744    12. Added -help and --help to pcretest as an official way of being reminded
745        of the options.
747    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
748        and pcrecpp.cc because they annoy compilers at high warning levels.
750    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
752    15. Fixed an occurrence of == in configure.ac that should have been = (shell
753        scripts are not C programs :-) and which was not noticed because it works
754        on Linux.
756    16. pcretest is supposed to handle any length of pattern and data line (as one
757        line or as a continued sequence of lines) by extending its input buffer if
758        necessary. This feature was broken for very long pattern lines, leading to
759        a string of junk being passed to pcre_compile() if the pattern was longer
760        than about 50K.
762    17. I have done a major re-factoring of the way pcre_compile() computes the
763        amount of memory needed for a compiled pattern. Previously, there was code
764        that made a preliminary scan of the pattern in order to do this. That was
765        OK when PCRE was new, but as the facilities have expanded, it has become
766        harder and harder to keep it in step with the real compile phase, and there
767        have been a number of bugs (see for example, 4 above). I have now found a
768        cunning way of running the real compile function in a "fake" mode that
769        enables it to compute how much memory it would need, while actually only
770        ever using a few hundred bytes of working memory and without too many
771        tests of the mode. This should make future maintenance and development
772        easier. A side effect of this work is that the limit of 200 on the nesting
773        depth of parentheses has been removed (though this was never a serious
774        limitation, I suspect). However, there is a downside: pcre_compile() now
775        runs more slowly than before (30% or more, depending on the pattern). I
776        hope this isn't a big issue. There is no effect on runtime performance.
778    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
779        newline (only possible for the last line of a file) and it was a
780        pattern that set a locale (followed by /Lsomething), pcretest crashed.
782    19. Added additional timing features to pcretest. (1) The -tm option now times
783        matching only, not compiling. (2) Both -t and -tm can be followed, as a
784        separate command line item, by a number that specifies the number of
785        repeats to use when timing. The default is 50000; this gives better
786        precision, but takes uncomfortably long for very large patterns.
788    20. Extended pcre_study() to be more clever in cases where a branch of a
789        subpattern has no definite first character. For example, (a*|b*)[cd] would
790        previously give no result from pcre_study(). Now it recognizes that the
791        first character must be a, b, c, or d.
793    21. There was an incorrect error "recursive call could loop indefinitely" if
794        a subpattern (or the entire pattern) that was being tested for matching an
795        empty string contained only one non-empty item after a nested subpattern.
796        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
797        incorrectly, because the \d was being skipped in the check.
799    22. The pcretest program now has a new pattern option /B and a command line
800        option -b, which is equivalent to adding /B to every pattern. This causes
801        it to show the compiled bytecode, without the additional information that
802        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
803        is the same as /B/I).
805    23. A new optimization is now able automatically to treat some sequences such
806        as a*b as a*+b. More specifically, if something simple (such as a character
807        or a simple class like \d) has an unlimited quantifier, and is followed by
808        something that cannot possibly match the quantified thing, the quantifier
809        is automatically "possessified".
811    24. A recursive reference to a subpattern whose number was greater than 39
812        went wrong under certain circumstances in UTF-8 mode. This bug could also
813        have affected the operation of pcre_study().
815    25. Realized that a little bit of performance could be had by replacing
816        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
818    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
820    27. Possessive quantifiers such as a++ were previously implemented by turning
821        them into atomic groups such as ($>a+). Now they have their own opcodes,
822        which improves performance. This includes the automatically created ones
823        from 23 above.
825    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
826        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
827        the first matched character to be a colon. This applied both to named and
828        numbered groups.
830    29. The ucpinternal.h header file was missing its idempotency #ifdef.
832    30. I was sent a "project" file called libpcre.a.dev which I understand makes
833        building PCRE on Windows easier, so I have included it in the distribution.
835    31. There is now a check in pcretest against a ridiculously large number being
836        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
837        loop, the loop is abandoned.
839    32. Forward references to subpatterns in conditions such as (?(2)...) where
840        subpattern 2 is defined later cause pcre_compile() to search forwards in
841        the pattern for the relevant set of parentheses. This search went wrong
842        when there were unescaped parentheses in a character class, parentheses
843        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
845    33. "Subroutine" calls and backreferences were previously restricted to
846        referencing subpatterns earlier in the regex. This restriction has now
847        been removed.
849    34. Added a number of extra features that are going to be in Perl 5.10. On the
850        whole, these are just syntactic alternatives for features that PCRE had
851        previously implemented using the Python syntax or my own invention. The
852        other formats are all retained for compatibility.
854        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
855            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
856            also .NET compatible.
858        (b) A recursion or subroutine call to a named group can now be defined as
859            (?&name) as well as (?P>name).
861        (c) A backreference to a named group can now be defined as \k<name> or
862            \k'name' as well as (?P=name). The new forms, as well as being in Perl
863            5.10, are also .NET compatible.
865        (d) A conditional reference to a named group can now use the syntax
866            (?(<name>) or (?('name') as well as (?(name).
868        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
869            groups (named and numbered) that are never evaluated inline, but can be
870            called as "subroutines" from elsewhere. In effect, the DEFINE condition
871            is always false. There may be only one alternative in such a group.
873        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
874            as the simple (?(R). The condition is true only if the most recent
875            recursion is that of the given number or name. It does not search out
876            through the entire recursion stack.
878        (g) The escape \gN or \g{N} has been added, where N is a positive or
879            negative number, specifying an absolute or relative reference.
881    35. Tidied to get rid of some further signed/unsigned compiler warnings and
882        some "unreachable code" warnings.
884    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
885        things, this adds five new scripts.
887    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
888        There were also incompatibilities regarding the handling of \Q..\E inside
889        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
890        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
892    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
893        matches an empty string, and forcibly breaks the loop. There were bugs in
894        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
895        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
896        separate and independent bugs (that affected different cases) have been
897        fixed.
899    39. Refactored the code to abolish the use of different opcodes for small
900        capturing bracket numbers. This is a tidy that I avoided doing when I
901        removed the limit on the number of capturing brackets for 3.5 back in 2001.
902        The new approach is not only tidier, it makes it possible to reduce the
903        memory needed to fix the previous bug (38).
905    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
906        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
907        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
908        mode.
910    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
911        report.
913    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
914        copy construction and assignment in the C++ wrapper.
916    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
917        couple of bugs that could have given wrong results in the "--newline=crlf"
918        case.
920    44. Added a number of casts and did some reorganization of signed/unsigned int
921        variables following suggestions from Dair Grant. Also renamed the variable
922        "this" as "item" because it is a C++ keyword.
924    45. Arranged for dftables to add
926          #include "pcre_internal.h"
928        to pcre_chartables.c because without it, gcc 4.x may remove the array
929        definition from the final binary if PCRE is built into a static library and
930        dead code stripping is activated.
932    46. For an unanchored pattern, if a match attempt fails at the start of a
933        newline sequence, and the newline setting is CRLF or ANY, and the next two
934        characters are CRLF, advance by two characters instead of one.
937    Version 6.7 04-Jul-06
938    ---------------------
940     1. In order to handle tests when input lines are enormously long, pcretest has
941        been re-factored so that it automatically extends its buffers when
942        necessary. The code is crude, but this _is_ just a test program. The
943        default size has been increased from 32K to 50K.
945     2. The code in pcre_study() was using the value of the re argument before
946        testing it for NULL. (Of course, in any sensible call of the function, it
947        won't be NULL.)
949     3. The memmove() emulation function in pcre_internal.h, which is used on
950        systems that lack both memmove() and bcopy() - that is, hardly ever -
951        was missing a "static" storage class specifier.
953     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
954        containing an extended class (one that cannot be represented by a bitmap
955        because it contains high-valued characters or Unicode property items, e.g.
956        [\pZ]). Almost always one would set UTF-8 mode when processing such a
957        pattern, but PCRE should not loop if you do not (it no longer does).
958        [Detail: two cases were found: (a) a repeated subpattern containing an
959        extended class; (b) a recursive reference to a subpattern that followed a
960        previous extended class. It wasn't skipping over the extended class
961        correctly when UTF-8 mode was not set.]
963     5. A negated single-character class was not being recognized as fixed-length
964        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
965        compile error "lookbehind assertion is not fixed length".
967     6. The RunPerlTest auxiliary script was showing an unexpected difference
968        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
969        write a Perl script that can interpret lines of an input file either as
970        byte characters or as UTF-8, which is what "perltest" was being required to
971        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
972        can't do is switch easily at run time between having the "use utf8;" pragma
973        or not. In the end, I fudged it by using the RunPerlTest script to insert
974        "use utf8;" explicitly for the UTF-8 tests.
976     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
977        the end of the subject string, contrary to the documentation and to what
978        Perl does. This was true of both matching functions. Now it matches only at
979        the start of the subject and immediately after *internal* newlines.
981     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
982        a pointer to an int instead of a pointer to an unsigned long int. This
983        caused problems on 64-bit systems.
985     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
986        instance of the 'standard' template library not being so standard".
988    10. There was no check on the number of named subpatterns nor the maximum
989        length of a subpattern name. The product of these values is used to compute
990        the size of the memory block for a compiled pattern. By supplying a very
991        long subpattern name and a large number of named subpatterns, the size
992        computation could be caused to overflow. This is now prevented by limiting
993        the length of names to 32 characters, and the number of named subpatterns
994        to 10,000.
996    11. Subpatterns that are repeated with specific counts have to be replicated in
997        the compiled pattern. The size of memory for this was computed from the
998        length of the subpattern and the repeat count. The latter is limited to
999        65535, but there was no limit on the former, meaning that integer overflow
1000        could in principle occur. The compiled length of a repeated subpattern is
1001        now limited to 30,000 bytes in order to prevent this.
1003    12. Added the optional facility to have named substrings with the same name.
1005    13. Added the ability to use a named substring as a condition, using the
1006        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1007        are numbers (not recommended). Forward references are permitted.
1009    14. Added forward references in named backreferences (if you see what I mean).
1011    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1012        pattern could run off the end of the subject. For example, the pattern
1013        "(?s)(.{1,5})"8 did this with the subject "ab".
1015    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1016        PCRE_CASELESS was set when matching characters that were quantified with ?
1017        or *.
1019    17. A character class other than a single negated character that had a minimum
1020        but no maximum quantifier - for example [ab]{6,} - was not handled
1021        correctly by pce_dfa_exec(). It would match only one character.
1023    18. A valid (though odd) pattern that looked like a POSIX character
1024        class but used an invalid character after [ (for example [[,abc,]]) caused
1025        pcre_compile() to give the error "Failed: internal error: code overflow" or
1026        in some cases to crash with a glibc free() error. This could even happen if
1027        the pattern terminated after [[ but there just happened to be a sequence of
1028        letters, a binary zero, and a closing ] in the memory that followed.
1030    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1031        over the years. Originally (before any Unicode support), just the bottom 8
1032        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1033        output from "man perlunicode" includes this:
1035          The regular expression compiler produces polymorphic opcodes.  That
1036          is, the pattern adapts to the data and automatically switches to
1037          the Unicode character scheme when presented with Unicode data--or
1038          instead uses a traditional byte scheme when presented with byte
1039          data.
1041        Sadly, a wide octal escape does not cause a switch, and in a string with
1042        no other multibyte characters, these octal escapes are treated as before.
1043        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1044        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1045        Unicode string.
1047        I have not perpetrated such confusion in PCRE. Up till now, it took just
1048        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1049        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1050        translate to the appropriate multibyte character.
1052    29. Applied some refactoring to reduce the number of warnings from Microsoft
1053        and Borland compilers. This has included removing the fudge introduced
1054        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1055        a warning about an unused variable.
1057    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1058        characters since release 4.0, because Perl (from release 5.004) does not.
1059        [Or at least, is documented not to: some releases seem to be in conflict
1060        with the documentation.] However, when a pattern was studied with
1061        pcre_study() and all its branches started with \s, PCRE still included VT
1062        as a possible starting character. Of course, this did no harm; it just
1063        caused an unnecessary match attempt.
1065    22. Removed a now-redundant internal flag bit that recorded the fact that case
1066        dependency changed within the pattern. This was once needed for "required
1067        byte" processing, but is no longer used. This recovers a now-scarce options
1068        bit. Also moved the least significant internal flag bit to the most-
1069        significant bit of the word, which was not previously used (hangover from
1070        the days when it was an int rather than a uint) to free up another bit for
1071        the future.
1073    23. Added support for CRLF line endings as well as CR and LF. As well as the
1074        default being selectable at build time, it can now be changed at runtime
1075        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1076        specify that it is scanning data with non-default line endings.
1078    24. Changed the definition of CXXLINK to make it agree with the definition of
1079        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1081    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1082        recursions. This makes a big different to stack usage for some patterns.
1084    26. If a subpattern containing a named recursion or subroutine reference such
1085        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1086        the space required for the compiled pattern went wrong and gave too small a
1087        value. Depending on the environment, this could lead to "Failed: internal
1088        error: code overflow at offset 49" or "glibc detected double free or
1089        corruption" errors.
1091    27. Applied patches from Google (a) to support the new newline modes and (b) to
1092        advance over multibyte UTF-8 characters in GlobalReplace.
1094    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1095        difference for some implementation of PCRE in some Windows version.
1097    29. Added some extra testing facilities to pcretest:
1099        \q<number>   in a data line sets the "match limit" value
1100        \Q<number>   in a data line sets the "match recursion limt" value
1101        -S <number>  sets the stack size, where <number> is in megabytes
1103        The -S option isn't available for Windows.
1106    Version 6.6 06-Feb-06
1107    ---------------------
1109     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1110        in pcreposix.h. I have copied the definition from pcre.h.
1112     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1113        because pcre.h is no longer a built file.
1115     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1116        not normally included in the compiled code.
1119    Version 6.5 01-Feb-06
1120    ---------------------
1122     1. When using the partial match feature with pcre_dfa_exec(), it was not
1123        anchoring the second and subsequent partial matches at the new starting
1124        point. This could lead to incorrect results. For example, with the pattern
1125        /1234/, partially matching against "123" and then "a4" gave a match.
1127     2. Changes to pcregrep:
1129        (a) All non-match returns from pcre_exec() were being treated as failures
1130            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1131            error message is output. Some extra information is given for the
1132            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1133            probably the only errors that are likely to be caused by users (by
1134            specifying a regex that has nested indefinite repeats, for instance).
1135            If there are more than 20 of these errors, pcregrep is abandoned.
1137        (b) A binary zero was treated as data while matching, but terminated the
1138            output line if it was written out. This has been fixed: binary zeroes
1139            are now no different to any other data bytes.
1141        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1142            used to set a locale for matching. The --locale=xxxx long option has
1143            been added (no short equivalent) to specify a locale explicitly on the
1144            pcregrep command, overriding the environment variables.
1146        (d) When -B was used with -n, some line numbers in the output were one less
1147            than they should have been.
1149        (e) Added the -o (--only-matching) option.
1151        (f) If -A or -C was used with -c (count only), some lines of context were
1152            accidentally printed for the final match.
1154        (g) Added the -H (--with-filename) option.
1156        (h) The combination of options -rh failed to suppress file names for files
1157            that were found from directory arguments.
1159        (i) Added the -D (--devices) and -d (--directories) options.
1161        (j) Added the -F (--fixed-strings) option.
1163        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1165        (l) Added the --colo(u)r option.
1167        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1168            is not present by default.
1170     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1171        items such as (?R) or (?1), when the recursion could match a number of
1172        alternatives. If it matched one of the alternatives, but subsequently,
1173        outside the recursion, there was a failure, the code tried to back up into
1174        the recursion. However, because of the way PCRE is implemented, this is not
1175        possible, and the result was an incorrect result from the match.
1177        In order to prevent this happening, the specification of recursion has
1178        been changed so that all such subpatterns are automatically treated as
1179        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1181     4. I had overlooked the fact that, in some locales, there are characters for
1182        which isalpha() is true but neither isupper() nor islower() are true. In
1183        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1184        and ordfeminine) are like this. This affected the treatment of \w and \W
1185        when they appeared in character classes, but not when they appeared outside
1186        a character class. The bit map for "word" characters is now created
1187        separately from the results of isalnum() instead of just taking it from the
1188        upper, lower, and digit maps. (Plus the underscore character, of course.)
1190     5. The above bug also affected the handling of POSIX character classes such as
1191        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1192        permanent tables. Instead, the bit maps for such a class were previously
1193        created as the appropriate unions of the upper, lower, and digit bitmaps.
1194        Now they are created by subtraction from the [[:word:]] class, which has
1195        its own bitmap.
1197     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1198        It is created by subtracting the vertical space characters (\x09, \x0a,
1199        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1200        subtraction was done in the overall bitmap for a character class, meaning
1201        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1202        be recognized. This bug has been fixed.
1204     7. Patches from the folks at Google:
1206          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1207          real life, but is still worth protecting against".
1209          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1210          regular expressions".
1212          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1213          have it.
1215          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1216          "configure" and the latter not, in order to fix a problem somebody had
1217          with compiling the Arg class on HP-UX.
1219          (e) Improve the error-handling of the C++ wrapper a little bit.
1221          (f) New tests for checking recursion limiting.
1223     8. The pcre_memmove() function, which is used only if the environment does not
1224        have a standard memmove() function (and is therefore rarely compiled),
1225        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1226        returning a result (though PCRE never actually uses the result).
1228     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1229        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1230        returned instead of calling malloc() with an overflowing number that would
1231        most likely cause subsequent chaos.
1233    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1235    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1236        with this option is matched, the nmatch and pmatch options of regexec() are
1237        ignored.
1239    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1240        provided in case anyone wants to the the POSIX interface with UTF-8
1241        strings.
1243    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1244        C++ linking (needed for some HP-UX environments).
1246    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1247        (unused parameter) and in the pcre_printint() function (omitted "default"
1248        switch label when the default is to do nothing).
1250    15. Added some code to make it possible, when PCRE is compiled as a C++
1251        library, to replace subject pointers for pcre_exec() with a smart pointer
1252        class, thus making it possible to process discontinuous strings.
1254    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1255        much the same function. They were added by different people who were trying
1256        to make PCRE easy to compile on non-Unix systems. It has been suggested
1257        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1258        for compiling on Windows systems. I have therefore replaced it with
1259        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1260        defaults to "extern" for C or "extern C" for C++, which works fine on
1261        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1262        SCOPE with something explicit in config.h. In addition:
1264        (a) pcreposix.h still had just "extern" instead of either of these macros;
1265            I have replaced it with PCRE_DATA_SCOPE.
1267        (b) Functions such as _pcre_xclass(), which are internal to the library,
1268            but external in the C sense, all had PCRE_EXPORT in their definitions.
1269            This is apparently wrong for the Windows case, so I have removed it.
1270            (It makes no difference on Unix-like systems.)
1272    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1273        of recursive calls to match(). This is different to MATCH_LIMIT because
1274        that limits the total number of calls to match(), not all of which increase
1275        the depth of recursion. Limiting the recursion depth limits the amount of
1276        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1277        when PCRE is compiled, and changed at run time. A patch from Google adds
1278        this functionality to the C++ interface.
1280    18. Changes to the handling of Unicode character properties:
1282        (a) Updated the table to Unicode 4.1.0.
1284        (b) Recognize characters that are not in the table as "Cn" (undefined).
1286        (c) I revised the way the table is implemented to a much improved format
1287            which includes recognition of ranges. It now supports the ranges that
1288            are defined in UnicodeData.txt, and it also amalgamates other
1289            characters into ranges. This has reduced the number of entries in the
1290            table from around 16,000 to around 3,000, thus reducing its size
1291            considerably. I realized I did not need to use a tree structure after
1292            all - a binary chop search is just as efficient. Having reduced the
1293            number of entries, I extended their size from 6 bytes to 8 bytes to
1294            allow for more data.
1296        (d) Added support for Unicode script names via properties such as \p{Han}.
1298    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1299        matching that character.
1301    20. When matching a repeated Unicode property with a minimum greater than zero,
1302        (for example \pL{2,}), PCRE could look past the end of the subject if it
1303        reached it while seeking the minimum number of characters. This could
1304        happen only if some of the characters were more than one byte long, because
1305        there is a check for at least the minimum number of bytes.
1307    21. Refactored the implementation of \p and \P so as to be more general, to
1308        allow for more different types of property in future. This has changed the
1309        compiled form incompatibly. Anybody with saved compiled patterns that use
1310        \p or \P will have to recompile them.
1312    22. Added "Any" and "L&" to the supported property types.
1314    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1315        but give a compile time error if the value is greater than 0xff.
1317    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1318        accidentally not being installed or uninstalled.
1320    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1321        made were to insert the current release number. This seemed silly, because
1322        it made things harder for people building PCRE on systems that don't run
1323        "configure". I have turned pcre.h into a distributed file, no longer built
1324        by "configure", with the version identification directly included. There is
1325        no longer a pcre.h.in file.
1327        However, this change necessitated a change to the pcre-config script as
1328        well. It is built from pcre-config.in, and one of the substitutions was the
1329        release number. I have updated configure.ac so that ./configure now finds
1330        the release number by grepping pcre.h.
1332    26. Added the ability to run the tests under valgrind.
1335    Version 6.4 05-Sep-05
1336    ---------------------
1338     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1339        "--" to be printed when multiple files were scanned, even when none of the
1340        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1341        consider it to be a bug, and have restored the previous behaviour.
1343     2. A couple of code tidies to get rid of compiler warnings.
1345     3. The pcretest program used to cheat by referring to symbols in the library
1346        whose names begin with _pcre_. These are internal symbols that are not
1347        really supposed to be visible externally, and in some environments it is
1348        possible to suppress them. The cheating is now confined to including
1349        certain files from the library's source, which is a bit cleaner.
1351     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1352        file's purpose clearer.
1354     5. Reorganized pcre_ucp_findchar().
1357    Version 6.3 15-Aug-05
1358    ---------------------
1360     1. The file libpcre.pc.in did not have general read permission in the tarball.
1362     2. There were some problems when building without C++ support:
1364        (a) If C++ support was not built, "make install" and "make test" still
1365            tried to test it.
1367        (b) There were problems when the value of CXX was explicitly set. Some
1368            changes have been made to try to fix these, and ...
1370        (c) --disable-cpp can now be used to explicitly disable C++ support.
1372        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1373            backslash in a target when C++ was disabled. This confuses some
1374            versions of "make", apparently. Using an intermediate variable solves
1375            this. (Same for CPP_LOBJ.)
1377     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1378        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1379        necessary on certain architectures.
1381     4. Added a setting of -export-symbols-regex to the link command to remove
1382        those symbols that are exported in the C sense, but actually are local
1383        within the library, and not documented. Their names all begin with
1384        "_pcre_". This is not a perfect job, because (a) we have to except some
1385        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1386        available (and never for static libraries). I have made a note to try to
1387        find a way round (a) in the future.
1390    Version 6.2 01-Aug-05
1391    ---------------------
1393     1. There was no test for integer overflow of quantifier values. A construction
1394        such as {1111111111111111} would give undefined results. What is worse, if
1395        a minimum quantifier for a parenthesized subpattern overflowed and became
1396        negative, the calculation of the memory size went wrong. This could have
1397        led to memory overwriting.
1399     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1401     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1402        operating environments where this matters.
1404     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1405        PCRE options from within the C++ wrapper.
1407     5. Named capturing subpatterns were not being correctly counted when a pattern
1408        was compiled. This caused two problems: (a) If there were more than 100
1409        such subpatterns, the calculation of the memory needed for the whole
1410        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1411        back references of the form \12, where the number was greater than 9, were
1412        not recognized as back references, even though there were sufficient
1413        previous subpatterns.
1415     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1416        versions of gcc, e.g. 2.95.4.
1419    Version 6.1 21-Jun-05
1420    ---------------------
1422     1. There was one reference to the variable "posix" in pcretest.c that was not
1423        surrounded by "#if !defined NOPOSIX".
1425     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1426        the cross-check on the old pcre_info() function, for the benefit of the
1427        cut-down version of PCRE that is currently imported into Exim.
1429     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1430        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1431        patterns that start (?i) but I don't think that matters. The use of (?i) is
1432        just an example; this all applies to the other options as well.
1434     4. Since libtool seems to echo the compile commands it is issuing, the output
1435        from "make" can be reduced a bit by putting "@" in front of each libtool
1436        compile command.
1438     5. Patch from the folks at Google for configure.in to be a bit more thorough
1439        in checking for a suitable C++ installation before trying to compile the
1440        C++ stuff. This should fix a reported problem when a compiler was present,
1441        but no suitable headers.
1443     6. The man pages all had just "PCRE" as their title. I have changed them to
1444        be the relevant file name. I have also arranged that these names are
1445        retained in the file doc/pcre.txt, which is a concatenation in text format
1446        of all the man pages except the little individual ones for each function.
1448     7. The NON-UNIX-USE file had not been updated for the different set of source
1449        files that come with release 6. I also added a few comments about the C++
1450        wrapper.
1453    Version 6.0 07-Jun-05
1454    ---------------------
1456     1. Some minor internal re-organization to help with my DFA experiments.
1458     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1459        didn't matter for the library itself when fully configured, but did matter
1460        when compiling without UCP support, or within Exim, where the ucp files are
1461        not imported.
1463     3. Refactoring of the library code to split up the various functions into
1464        different source modules. The addition of the new DFA matching code (see
1465        below) to a single monolithic source would have made it really too
1466        unwieldy, quite apart from causing all the code to be include in a
1467        statically linked application, when only some functions are used. This is
1468        relevant even without the DFA addition now that patterns can be compiled in
1469        one application and matched in another.
1471        The downside of splitting up is that there have to be some external
1472        functions and data tables that are used internally in different modules of
1473        the library but which are not part of the API. These have all had their
1474        names changed to start with "_pcre_" so that they are unlikely to clash
1475        with other external names.
1477     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1478        a different (DFA) algorithm. Although it is slower than the original
1479        function, it does have some advantages for certain types of matching
1480        problem.
1482     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1483        including restarting after a partial match.
1485     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1486        defined when compiling for Windows was sent to me. I have put it into the
1487        code, though I have no means of testing or verifying it.
1489     7. Added the pcre_refcount() auxiliary function.
1491     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1492        match before or at the first newline in the subject string. In pcretest,
1493        the /f option on a pattern can be used to set this.
1495     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1496        would behave wrongly. This has been present in PCRE since release 4.0.
1498    10. A number of changes to the pcregrep command:
1500        (a) Refactored how -x works; insert ^(...)$ instead of setting
1501            PCRE_ANCHORED and checking the length, in preparation for adding
1502            something similar for -w.
1504        (b) Added the -w (match as a word) option.
1506        (c) Refactored the way lines are read and buffered so as to have more
1507            than one at a time available.
1509        (d) Implemented a pcregrep test script.
1511        (e) Added the -M (multiline match) option. This allows patterns to match
1512            over several lines of the subject. The buffering ensures that at least
1513            8K, or the rest of the document (whichever is the shorter) is available
1514            for matching (and similarly the previous 8K for lookbehind assertions).
1516        (f) Changed the --help output so that it now says
1518              -w, --word-regex(p)
1520            instead of two lines, one with "regex" and the other with "regexp"
1521            because that confused at least one person since the short forms are the
1522            same. (This required a bit of code, as the output is generated
1523            automatically from a table. It wasn't just a text change.)
1525        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1526            option but starts with a hyphen. Could be a pattern or a path name
1527            starting with a hyphen, for instance.
1529        (h) "-" can be given as a file name to represent stdin.
1531        (i) When file names are being printed, "(standard input)" is used for
1532            the standard input, for compatibility with GNU grep. Previously
1533            "<stdin>" was used.
1535        (j) The option --label=xxx can be used to supply a name to be used for
1536            stdin when file names are being printed. There is no short form.
1538        (k) Re-factored the options decoding logic because we are going to add
1539            two more options that take data. Such options can now be given in four
1540            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1542        (l) Added the -A, -B, and -C options for requesting that lines of context
1543            around matches be printed.
1545        (m) Added the -L option to print the names of files that do not contain
1546            any matching lines, that is, the complement of -l.
1548        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1549            continue to scan other files.
1551        (o) The -s option was incorrectly implemented. For compatibility with other
1552            greps, it now suppresses the error message for a non-existent or non-
1553            accessible file (but not the return code). There is a new option called
1554            -q that suppresses the output of matching lines, which was what -s was
1555            previously doing.
1557        (p) Added --include and --exclude options to specify files for inclusion
1558            and exclusion when recursing.
1560    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1561        Hopefully, it now does.
1563    12. Missing cast in pcre_study().
1565    13. Added an "uninstall" target to the makefile.
1567    14. Replaced "extern" in the function prototypes in Makefile.in with
1568        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1569        world, but is set differently for Windows.
1571    15. Added a second compiling function called pcre_compile2(). The only
1572        difference is that it has an extra argument, which is a pointer to an
1573        integer error code. When there is a compile-time failure, this is set
1574        non-zero, in addition to the error test pointer being set to point to an
1575        error message. The new argument may be NULL if no error number is required
1576        (but then you may as well call pcre_compile(), which is now just a
1577        wrapper). This facility is provided because some applications need a
1578        numeric error indication, but it has also enabled me to tidy up the way
1579        compile-time errors are handled in the POSIX wrapper.
1581    16. Added VPATH=.libs to the makefile; this should help when building with one
1582        prefix path and installing with another. (Or so I'm told by someone who
1583        knows more about this stuff than I do.)
1585    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1586        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1587        match everything, including newlines. This is not POSIX-compatible, but
1588        somebody wanted the feature. From pcretest it can be activated by using
1589        both the P and the s flags.
1591    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1593    19. libpcre.pc was being incorrectly installed as executable.
1595    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1596        it now also looks for '\r' so that it will work unmodified on Windows.
1598    21. Added Google's contributed C++ wrapper to the distribution.
1600    22. Added some untidy missing memory free() calls in pcretest, to keep
1601        Electric Fence happy when testing.
1605    Version 5.0 13-Sep-04
1606    ---------------------
1608     1. Internal change: literal characters are no longer packed up into items
1609        containing multiple characters in a single byte-string. Each character
1610        is now matched using a separate opcode. However, there may be more than one
1611        byte in the character in UTF-8 mode.
1613     2. The pcre_callout_block structure has two new fields: pattern_position and
1614        next_item_length. These contain the offset in the pattern to the next match
1615        item, and its length, respectively.
1617     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1618        insertion of callouts before each pattern item. Added the /C option to
1619        pcretest to make use of this.
1621     4. On the advice of a Windows user, the lines
1623          #if defined(_WIN32) || defined(WIN32)
1624          _setmode( _fileno( stdout ), 0x8000 );
1625          #endif  /* defined(_WIN32) || defined(WIN32) */
1627        have been added to the source of pcretest. This apparently does useful
1628        magic in relation to line terminators.
1630     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1631        for the benefit of those environments where the "b" makes a difference.
1633     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1634        to know about it. I have put a hack into configure.in that adds in code
1635        to set GCC=yes if CC=icc. This seems to end up at a point in the
1636        generated configure script that is early enough to affect the setting of
1637        compiler options, which is what is needed, but I have no means of testing
1638        whether it really works. (The user who reported this had patched the
1639        generated configure script, which of course I cannot do.)
1641        LATER: After change 22 below (new libtool files), the configure script
1642        seems to know about icc (and also ecc). Therefore, I have commented out
1643        this hack in configure.in.
1645     7. Added support for pkg-config (2 patches were sent in).
1647     8. Negated POSIX character classes that used a combination of internal tables
1648        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1649        [[:^ascii]]. Typically, they would match almost any characters. The other
1650        POSIX classes were not broken in this way.
1652     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1653        to find the match, as PCRE was deluded into thinking that the match had to
1654        start at the start point or following a newline. The same bug applied to
1655        patterns with negative forward assertions or any backward assertions
1656        preceding ".*" at the start, unless the pattern required a fixed first
1657        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1659    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1660        starting at the last subject character, bytes beyond the end of the subject
1661        string were read.
1663    11. Renamed the variable "class" as "classbits" to make life easier for C++
1664        users. (Previously there was a macro definition, but it apparently wasn't
1665        enough.)
1667    12. Added the new field "tables" to the extra data so that tables can be passed
1668        in at exec time, or the internal tables can be re-selected. This allows
1669        a compiled regex to be saved and re-used at a later time by a different
1670        program that might have everything at different addresses.
1672    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1673        -R library as well as a -L library.
1675    14. The debugging options of pcretest (-d on the command line or D on a
1676        pattern) showed incorrect output for anything following an extended class
1677        that contained multibyte characters and which was followed by a quantifier.
1679    15. Added optional support for general category Unicode character properties
1680        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1681        support. It adds about 90K to the size of the library. The meanings of the
1682        inbuilt class escapes such as \d and \s have NOT been changed.
1684    16. Updated pcredemo.c to include calls to free() to release the memory for the
1685        compiled pattern.
1687    17. The generated file chartables.c was being created in the source directory
1688        instead of in the building directory. This caused the build to fail if the
1689        source directory was different from the building directory, and was
1690        read-only.
1692    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1693        file. No doubt somebody will tell me if they don't make sense... Also added
1694        Dan Mooney's comments about building on OpenVMS.
1696    19. Added support for partial matching via the PCRE_PARTIAL option for
1697        pcre_exec() and the \P data escape in pcretest.
1699    20. Extended pcretest with 3 new pattern features:
1701        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1702              write the compiled pattern to the file whose name is "rest-of-line".
1703              This is a straight binary dump of the data, with the saved pointer to
1704              the character tables forced to be NULL. The study data, if any, is
1705              written too. After writing, pcretest reads a new pattern.
1707        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1708              compiled pattern from the given file. There must not be any
1709              occurrences of "<" in the file name (pretty unlikely); if there are,
1710              pcretest will instead treat the initial "<" as a pattern delimiter.
1711              After reading in the pattern, pcretest goes on to read data lines as
1712              usual.
1714        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1715              and 16-bit fields in a compiled pattern, to simulate a pattern that
1716              was compiled on a host of opposite endianness.
1718    21. The pcre-exec() function can now cope with patterns that were compiled on
1719        hosts of opposite endianness, with this restriction:
1721          As for any compiled expression that is saved and used later, the tables
1722          pointer field cannot be preserved; the extra_data field in the arguments
1723          to pcre_exec() should be used to pass in a tables address if a value
1724          other than the default internal tables were used at compile time.
1726    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1727        now diagnosed as an error. Previously, most of the time, a negative number
1728        would have been treated as zero, but if in addition "ovector" was passed as
1729        NULL, a crash could occur.
1731    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1732        new versions from the libtool 1.5 distribution (the last one is a copy of
1733        a file called libtool.m4). This seems to have fixed the need to patch
1734        "configure" to support Darwin 1.3 (which I used to do). However, I still
1735        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1736        workstation).
1738    24. Changed the PCRE licence to be the more standard "BSD" licence.
1741    Version 4.5 01-Dec-03
1742    ---------------------
1744     1. There has been some re-arrangement of the code for the match() function so
1745        that it can be compiled in a version that does not call itself recursively.
1746        Instead, it keeps those local variables that need separate instances for
1747        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1748        needs to "recurse". Keeping track of where control must go is done by means
1749        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1750        hide most of the details from the main code, and operates only if
1751        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1752        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1753        operating.
1755        To make it easier for callers to provide specially tailored get/free
1756        functions for this usage, two new functions, pcre_stack_malloc, and
1757        pcre_stack_free, are used. They are always called in strict stacking order,
1758        and the size of block requested is always the same.
1760        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1761        PCRE has been compiled to use the stack or the heap for recursion. The
1762        -C option of pcretest uses this to show which version is compiled.
1764        A new data escape \S, is added to pcretest; it causes the amounts of store
1765        obtained and freed by both kinds of malloc/free at match time to be added
1766        to the output.
1768     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1769        what's available on my current Linux desktop machine.
1771     3. When matching a UTF-8 string, the test for a valid string at the start has
1772        been extended. If start_offset is not zero, PCRE now checks that it points
1773        to a byte that is the start of a UTF-8 character. If not, it returns
1774        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1775        this is necessary because there may be backward assertions in the pattern.
1776        When matching the same subject several times, it may save resources to use
1777        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1779     4. The code for checking the validity of UTF-8 strings has been tightened so
1780        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1781        containing "overlong sequences".
1783     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1784        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1785        should have been "&", but it just so happened that all the cases this let
1786        through by mistake were picked up later in the function.
1788     6. I had used a variable called "isblank" - this is a C99 function, causing
1789        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1791     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1792        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1793        so the version is shown; (c) stop "make test" echoing "./RunTest".
1795     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1797     9. The prototype for memmove() for systems that don't have it was using
1798        size_t, but the inclusion of the header that defines size_t was later. I've
1799        moved the #includes for the C headers earlier to avoid this.
1801    10. Added some adjustments to the code to make it easier to compiler on certain
1802        special systems:
1804          (a) Some "const" qualifiers were missing.
1805          (b) Added the macro EXPORT before all exported functions; by default this
1806              is defined to be empty.
1807          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1808              that it reads its output file name as an argument instead of writing
1809              to the standard output and assuming this can be redirected.
1811    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1812        class containing characters with values greater than 255, PCRE compilation
1813        went into a loop.
1815    12. A recursive reference to a subpattern that was within another subpattern
1816        that had a minimum quantifier of zero caused PCRE to crash. For example,
1817        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1818        recursion. If the recursively-called subpattern itself had a zero repeat,
1819        that was OK.
1821    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1822        buffer into which it was copied (for escape processing) was still set at
1823        1024, so long lines caused crashes.
1825    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1826        "internal error: code overflow...". This applied to any character class
1827        that was followed by a possessive quantifier.
1829    15. Modified the Makefile to add libpcre.la as a prerequisite for
1830        libpcreposix.la because I was told this is needed for a parallel build to
1831        work.
1833    16. If a pattern that contained .* following optional items at the start was
1834        studied, the wrong optimizing data was generated, leading to matching
1835        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1836        matching string must start with a or b or c. The correct conclusion for
1837        this pattern is that a match can start with any character.
1840    Version 4.4 13-Aug-03
1841    ---------------------
1843     1. In UTF-8 mode, a character class containing characters with values between
1844        127 and 255 was not handled correctly if the compiled pattern was studied.
1845        In fixing this, I have also improved the studying algorithm for such
1846        classes (slightly).
1848     2. Three internal functions had redundant arguments passed to them. Removal
1849        might give a very teeny performance improvement.
1851     3. Documentation bug: the value of the capture_top field in a callout is *one
1852        more than* the number of the hightest numbered captured substring.
1854     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1855        in incorrectly linking with a previously installed version. They now link
1856        explicitly with libpcre.la.
1858     5. configure.in no longer needs to recognize Cygwin specially.
1860     6. A problem in pcre.in for Windows platforms is fixed.
1862     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1863        pcretest, it used to include the size of the study block as part of its
1864        output. Unfortunately, the structure contains a field that has a different
1865        size on different hardware architectures. This meant that the tests that
1866        showed this size failed. As the block is currently always of a fixed size,
1867        this information isn't actually particularly useful in pcretest output, so
1868        I have just removed it.
1870     8. Three pre-processor statements accidentally did not start in column 1.
1871        Sadly, there are *still* compilers around that complain, even though
1872        standard C has not required this for well over a decade. Sigh.
1874     9. In pcretest, the code for checking callouts passed small integers in the
1875        callout_data field, which is a void * field. However, some picky compilers
1876        complained about the casts involved for this on 64-bit systems. Now
1877        pcretest passes the address of the small integer instead, which should get
1878        rid of the warnings.
1880    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1881        both compile and run time, and gives an error if an invalid UTF-8 sequence
1882        is found. There is a option for disabling this check in cases where the
1883        string is known to be correct and/or the maximum performance is wanted.
1885    11. In response to a bug report, I changed one line in Makefile.in from
1887            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1888        to
1889            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1891        to look similar to other lines, but I have no way of telling whether this
1892        is the right thing to do, as I do not use Windows. No doubt I'll get told
1893        if it's wrong...
1896  Version 4.3 21-May-03  Version 4.3 21-May-03
1897  ---------------------  ---------------------

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