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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.4 21-Sep-07
5    ---------------------
7    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
8        means that a class such as [\s] counted as "explicit reference to CR or
9        LF". That isn't really right - the whole point of the change was to try to
10        help when there was an actual mention of one of the two characters. So now
11        the change happens only if \r or \n (or a literal CR or LF) character is
12        encountered.
14    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
15        of both had grown to the point where there were only 3 bits left.
16        Fortunately, there was spare space in the data structure, and so I have
17        moved the internal flags into a new 16-bit field to free up more option
18        bits.
20    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
21        but did not set the internal JCHANGED flag - either of these is enough to
22        control the way the "get" function works - but the PCRE_INFO_JCHANGED
23        facility is supposed to tell if (?J) was ever used, so now (?J) at the
24        start sets both bits.
26    4.  Added options (at build time, compile time, exec time) to change \R from
27        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
29    5.  doc/pcresyntax.html was missing from the distribution.
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
34    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
35        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
36        windows.h file is present (where different names are used). [This was
37        reversed later after testing - see 16 below.]
39    8.  Changed all #include <config.h> to #include "config.h". There were also
40        some further <pcre.h> cases that I changed to "pcre.h".
42    9.  When pcregrep was used with the --colour option, it missed the line ending
43        sequence off the lines that it output.
45    10. It was pointed out to me that arrays of string pointers cause lots of
46        relocations when a shared library is dynamically loaded. A technique of
47        using a single long string with a table of offsets can drastically reduce
48        these. I have refactored PCRE in four places to do this. The result is
49        dramatic:
51          Originally:                          290
52          After changing UCP table:            187
53          After changing error message table:   43
54          After changing table of "verbs"       36
55          After changing table of Posix names   22
57        Thanks to the folks working on Gregex for glib for this insight.
59    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
60        unicode-properties was also set.
62    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
64    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
65        checked only for CRLF.
67    14. Added casts to pcretest.c to avoid compiler warnings.
69    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
71    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
72        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
73        entirely. This removes changes made in 7 above.
76    Version 7.3 28-Aug-07
77    ---------------------
79     1. In the rejigging of the build system that eventually resulted in 7.1, the
80        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
81        brackets there is not right, since it causes compilers to look for an
82        installed pcre.h, not the version that is in the source that is being
83        compiled (which of course may be different). I have changed it back to:
85          #include "pcre.h"
87        I have a vague recollection that the change was concerned with compiling in
88        different directories, but in the new build system, that is taken care of
89        by the VPATH setting the Makefile.
91     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
92        when the subject happened to end in the byte 0x85 (e.g. if the last
93        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
94        characters but of course it shouldn't be taken as a newline when it is part
95        of another character. The bug was that, for an unlimited repeat of . in
96        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
97        characters when looking for a newline.
99     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
101     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
102        in debug output.
104     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
105        long printing in the pcrecpp unittest when running under MinGW.
107     6. ESC_K was left out of the EBCDIC table.
109     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
110        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
111        limit also applies to "virtual nesting" when a pattern is recursive, and in
112        this case 1000 isn't so big. I have been able to remove this limit at the
113        expense of backing off one optimization in certain circumstances. Normally,
114        when pcre_exec() would call its internal match() function recursively and
115        immediately return the result unconditionally, it uses a "tail recursion"
116        feature to save stack. However, when a subpattern that can match an empty
117        string has an unlimited repetition quantifier, it no longer makes this
118        optimization. That gives it a stack frame in which to save the data for
119        checking that an empty string has been matched. Previously this was taken
120        from the 1000-entry workspace that had been reserved. So now there is no
121        explicit limit, but more stack is used.
123     8. Applied Daniel's patches to solve problems with the import/export magic
124        syntax that is required for Windows, and which was going wrong for the
125        pcreposix and pcrecpp parts of the library. These were overlooked when this
126        problem was solved for the main library.
128     9. There were some crude static tests to avoid integer overflow when computing
129        the size of patterns that contain repeated groups with explicit upper
130        limits. As the maximum quantifier is 65535, the maximum group length was
131        set at 30,000 so that the product of these two numbers did not overflow a
132        32-bit integer. However, it turns out that people want to use groups that
133        are longer than 30,000 bytes (though not repeat them that many times).
134        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
135        made it possible to implement the integer overflow checks in a much more
136        dynamic way, which I have now done. The artificial limitation on group
137        length has been removed - we now have only the limit on the total length of
138        the compiled pattern, which depends on the LINK_SIZE setting.
140    10. Fixed a bug in the documentation for get/copy named substring when
141        duplicate names are permitted. If none of the named substrings are set, the
142        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
143        empty string.
145    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
146        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
147        because the ] is interpreted as the first data character and the
148        terminating ] is not found. PCRE has been made compatible with Perl in this
149        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
150        cause memory overwriting.
152    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
153        string has been matched (to stop an infinite loop). It was not recognizing
154        a conditional subpattern that could match an empty string if that
155        subpattern was within another subpattern. For example, it looped when
156        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
157        condition was not nested. This bug has been fixed.
159    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
160        past the start of the subject in the presence of bytes with the top bit
161        set, for example "\x8aBCD".
163    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
164        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
166    14. Optimized (?!) to (*FAIL).
168    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
169        This restricts code points to be within the range 0 to 0x10FFFF, excluding
170        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
171        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
172        does: it's just the validity check that is more restrictive.
174    16. Inserted checks for integer overflows during escape sequence (backslash)
175        processing, and also fixed erroneous offset values for syntax errors during
176        backslash processing.
178    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
179        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
181    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
182        caused an overrun.
184    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
185        something other than just ASCII characters) inside a group that had an
186        unlimited repeat caused a loop at compile time (while checking to see
187        whether the group could match an empty string).
189    20. Debugging a pattern containing \p or \P could cause a crash. For example,
190        [\P{Any}] did so. (Error in the code for printing property names.)
192    21. An orphan \E inside a character class could cause a crash.
194    22. A repeated capturing bracket such as (A)? could cause a wild memory
195        reference during compilation.
197    23. There are several functions in pcre_compile() that scan along a compiled
198        expression for various reasons (e.g. to see if it's fixed length for look
199        behind). There were bugs in these functions when a repeated \p or \P was
200        present in the pattern. These operators have additional parameters compared
201        with \d, etc, and these were not being taken into account when moving along
202        the compiled data. Specifically:
204        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
205            length.
207        (b) An item such as \pL+ within a repeated group could cause crashes or
208            loops.
210        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
211            "reference to non-existent subpattern" error.
213        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
215    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
216        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
218    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
220    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
221        character were causing crashes (broken optimization).
223    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
224        \p or \P) caused a compile-time loop.
226    28. More problems have arisen in unanchored patterns when CRLF is a valid line
227        break. For example, the unstudied pattern [\r\n]A does not match the string
228        "\r\nA" because change 7.0/46 below moves the current point on by two
229        characters after failing to match at the start. However, the pattern \nA
230        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
231        the same is true. There doesn't seem any very clean way out of this, but
232        what I have chosen to do makes the common cases work: PCRE now takes note
233        of whether there can be an explicit match for \r or \n anywhere in the
234        pattern, and if so, 7.0/46 no longer applies. As part of this change,
235        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
236        pattern has explicit CR or LF references.
238    29. Added (*CR) etc for changing newline setting at start of pattern.
241    Version 7.2 19-Jun-07
242    ---------------------
244     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
245        which is apparently normally available under Windows.
247     2. Re-jig the pcregrep tests with different newline settings in an attempt
248        to make them independent of the local environment's newline setting.
250     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
252     4. Some of the "internals" tests were previously cut out when the link size
253        was not 2, because the output contained actual offsets. The recent new
254        "Z" feature of pcretest means that these can be cut out, making the tests
255        usable with all link sizes.
257     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
258        stack recursion. This gives a massive performance boost under BSD, but just
259        a small improvement under Linux. However, it saves one field in the frame
260        in all cases.
262     6. Added more features from the forthcoming Perl 5.10:
264        (a) (?-n) (where n is a string of digits) is a relative subroutine or
265            recursion call. It refers to the nth most recently opened parentheses.
267        (b) (?+n) is also a relative subroutine call; it refers to the nth next
268            to be opened parentheses.
270        (c) Conditions that refer to capturing parentheses can be specified
271            relatively, for example, (?(-2)... or (?(+3)...
273        (d) \K resets the start of the current match so that everything before
274            is not part of it.
276        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
278        (f) \g{name} is another synonym - part of Perl 5.10's unification of
279            reference syntax.
281        (g) (?| introduces a group in which the numbering of parentheses in each
282            alternative starts with the same number.
284        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
286     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
289     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
290        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
291        for detecting groups that can match an empty string.
293     9. A pattern with a very large number of alternatives (more than several
294        hundred) was running out of internal workspace during the pre-compile
295        phase, where pcre_compile() figures out how much memory will be needed. A
296        bit of new cunning has reduced the workspace needed for groups with
297        alternatives. The 1000-alternative test pattern now uses 12 bytes of
298        workspace instead of running out of the 4096 that are available.
300    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
302    11. Applied patch from Google to remove an optimization that didn't quite work.
303        The report of the bug said:
305          pcrecpp::RE("a*").FullMatch("aaa") matches, while
306          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
307          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
309    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
310        it matched the wrong number of bytes.
313    Version 7.1 24-Apr-07
314    ---------------------
316     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
317        that is more "standard", making use of automake and other Autotools. There
318        is some re-arrangement of the files and adjustment of comments consequent
319        on this.
321     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
322        for recursive directory scanning broke on some systems because the files
323        are not scanned in any specific order and on different systems the order
324        was different. A call to "sort" has been inserted into RunGrepTest for the
325        approprate test as a short-term fix. In the longer term there may be an
326        alternative.
328     3. I had an email from Eric Raymond about problems translating some of PCRE's
329        man pages to HTML (despite the fact that I distribute HTML pages, some
330        people do their own conversions for various reasons). The problems
331        concerned the use of low-level troff macros .br and .in. I have therefore
332        removed all such uses from the man pages (some were redundant, some could
333        be replaced by .nf/.fi pairs). The 132html script that I use to generate
334        HTML has been updated to handle .nf/.fi and to complain if it encounters
335        .br or .in.
337     4. Updated comments in configure.ac that get placed in config.h.in and also
338        arranged for config.h to be included in the distribution, with the name
339        config.h.generic, for the benefit of those who have to compile without
340        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
342     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
343        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
344        makevp.bat for the current PCRE, using the additional files
345        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
347     6. A Windows user reported a minor discrepancy with test 2, which turned out
348        to be caused by a trailing space on an input line that had got lost in his
349        copy. The trailing space was an accident, so I've just removed it.
351     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
352        that is needed.
354     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
355        as "const" (a) because they are and (b) because it helps the PHP
356        maintainers who have recently made a script to detect big data structures
357        in the php code that should be moved to the .rodata section. I remembered
358        to update Builducptable as well, so it won't revert if ucptable.h is ever
359        re-created.
361     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
362        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
363        order to be able to cut out the UTF-8 tables in the latter when UTF-8
364        support is not required. This saves 1.5-2K of code, which is important in
365        some applications.
367        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
368        so as not to refer to the tables, even though these functions will never be
369        called when UTF-8 support is disabled. Otherwise there are problems with a
370        shared library.
372    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
374        (a) It was defining its arguments as char * instead of void *.
376        (b) It was assuming that all moves were upwards in memory; this was true
377            a long time ago when I wrote it, but is no longer the case.
379        The emulated memove() is provided for those environments that have neither
380        memmove() nor bcopy(). I didn't think anyone used it these days, but that
381        is clearly not the case, as these two bugs were recently reported.
383    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
384        and Detrail to create the HTML documentation, the .txt form of the man
385        pages, and it removes trailing spaces from listed files. It also creates
386        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
387        case, it wraps all the #defines with #ifndefs. This script should be run
388        before "make dist".
390    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
391        with Unicode property support.
393        (a) For a maximizing quantifier, if the two different cases of the
394            character were of different lengths in their UTF-8 codings (there are
395            some cases like this - I found 11), and the matching function had to
396            back up over a mixture of the two cases, it incorrectly assumed they
397            were both the same length.
399        (b) When PCRE was configured to use the heap rather than the stack for
400            recursion during matching, it was not correctly preserving the data for
401            the other case of a UTF-8 character when checking ahead for a match
402            while processing a minimizing repeat. If the check also involved
403            matching a wide character, but failed, corruption could cause an
404            erroneous result when trying to check for a repeat of the original
405            character.
407    13. Some tidying changes to the testing mechanism:
409        (a) The RunTest script now detects the internal link size and whether there
410            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
411            values substituted by "configure". (The RunGrepTest script already did
412            this for UTF-8.) The configure.ac script no longer substitutes the
413            relevant variables.
415        (b) The debugging options /B and /D in pcretest show the compiled bytecode
416            with length and offset values. This means that the output is different
417            for different internal link sizes. Test 2 is skipped for link sizes
418            other than 2 because of this, bypassing the problem. Unfortunately,
419            there was also a test in test 3 (the locale tests) that used /B and
420            failed for link sizes other than 2. Rather than cut the whole test out,
421            I have added a new /Z option to pcretest that replaces the length and
422            offset values with spaces. This is now used to make test 3 independent
423            of link size. (Test 2 will be tidied up later.)
425    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
426        segmentation fault instead of returning the appropriate error message.
428    15. In multiline mode when the newline sequence was set to "any", the pattern
429        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
430        This doesn't seem right; it now treats the CRLF combination as the line
431        ending, and so does not match in that case. It's only a pattern such as ^$
432        that would hit this one: something like ^ABC$ would have failed after \r
433        and then tried again after \r\n.
435    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
436        in an attempt to make files that differ only in their line terminators
437        compare equal. This works on Linux.
439    17. Under certain error circumstances pcregrep might try to free random memory
440        as it exited. This is now fixed, thanks to valgrind.
442    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
443        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
444        was because its rules for how to advance for /g after matching an empty
445        string at the end of a line did not allow for this case. They now check for
446        it specially.
448    20. pcretest is supposed to handle patterns and data of any length, by
449        extending its buffers when necessary. It was getting this wrong when the
450        buffer for a data line had to be extended.
452    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
453        CRLF as a newline sequence.
455    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
456        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
457        I have nevertheless tidied it up.
459    23. Added some casts to kill warnings from HP-UX ia64 compiler.
461    24. Added a man page for pcre-config.
464    Version 7.0 19-Dec-06
465    ---------------------
467     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
468        moving to gcc 4.1.1.
470     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
471        sys/time.h, which is documented as needed for this function. It doesn't
472        seem to matter on Linux, but it showed up on some releases of OS X.
474     3. It seems that there are systems where bytes whose values are greater than
475        127 match isprint() in the "C" locale. The "C" locale should be the
476        default when a C program starts up. In most systems, only ASCII printing
477        characters match isprint(). This difference caused the output from pcretest
478        to vary, making some of the tests fail. I have changed pcretest so that:
480        (a) When it is outputting text in the compiled version of a pattern, bytes
481            other than 32-126 are always shown as hex escapes.
483        (b) When it is outputting text that is a matched part of a subject string,
484            it does the same, unless a different locale has been set for the match
485            (using the /L modifier). In this case, it uses isprint() to decide.
487     4. Fixed a major bug that caused incorrect computation of the amount of memory
488        required for a compiled pattern when options that changed within the
489        pattern affected the logic of the preliminary scan that determines the
490        length. The relevant options are -x, and -i in UTF-8 mode. The result was
491        that the computed length was too small. The symptoms of this bug were
492        either the PCRE error "internal error: code overflow" from pcre_compile(),
493        or a glibc crash with a message such as "pcretest: free(): invalid next
494        size (fast)". Examples of patterns that provoked this bug (shown in
495        pcretest format) are:
497          /(?-x: )/x
498          /(?x)(?-x: \s*#\s*)/
499          /((?i)[\x{c0}])/8
500          /(?i:[\x{c0}])/8
502        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
503        is now done differently.
505     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
506        wrapper classes; (b) implement a new function in the C++ scanner that is
507        more efficient than the old way of doing things because it avoids levels of
508        recursion in the regex matching; (c) add a paragraph to the documentation
509        for the FullMatch() function.
511     6. The escape sequence \n was being treated as whatever was defined as
512        "newline". Not only was this contrary to the documentation, which states
513        that \n is character 10 (hex 0A), but it also went horribly wrong when
514        "newline" was defined as CRLF. This has been fixed.
516     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
517        was being set to -1 for the "end of line" case (supposedly a value that no
518        character can have). Though this value is never used (the check for end of
519        line is "zero bytes in current character"), it caused compiler complaints.
520        I've changed it to 0xffffffff.
522     8. In pcre_version.c, the version string was being built by a sequence of
523        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
524        string (as it is for production releases) called a macro with an empty
525        argument. The C standard says the result of this is undefined. The gcc
526        compiler treats it as an empty string (which was what was wanted) but it is
527        reported that Visual C gives an error. The source has been hacked around to
528        avoid this problem.
530     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
531        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
532        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
533        of them did).
535    10. Originally, pcretest opened its input and output without "b"; then I was
536        told that "b" was needed in some environments, so it was added for release
537        5.0 to both the input and output. (It makes no difference on Unix-like
538        systems.) Later I was told that it is wrong for the input on Windows. I've
539        now abstracted the modes into two macros, to make it easier to fiddle with
540        them, and removed "b" from the input mode under Windows.
542    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
544    12. Added -help and --help to pcretest as an official way of being reminded
545        of the options.
547    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
548        and pcrecpp.cc because they annoy compilers at high warning levels.
550    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
552    15. Fixed an occurrence of == in configure.ac that should have been = (shell
553        scripts are not C programs :-) and which was not noticed because it works
554        on Linux.
556    16. pcretest is supposed to handle any length of pattern and data line (as one
557        line or as a continued sequence of lines) by extending its input buffer if
558        necessary. This feature was broken for very long pattern lines, leading to
559        a string of junk being passed to pcre_compile() if the pattern was longer
560        than about 50K.
562    17. I have done a major re-factoring of the way pcre_compile() computes the
563        amount of memory needed for a compiled pattern. Previously, there was code
564        that made a preliminary scan of the pattern in order to do this. That was
565        OK when PCRE was new, but as the facilities have expanded, it has become
566        harder and harder to keep it in step with the real compile phase, and there
567        have been a number of bugs (see for example, 4 above). I have now found a
568        cunning way of running the real compile function in a "fake" mode that
569        enables it to compute how much memory it would need, while actually only
570        ever using a few hundred bytes of working memory and without too many
571        tests of the mode. This should make future maintenance and development
572        easier. A side effect of this work is that the limit of 200 on the nesting
573        depth of parentheses has been removed (though this was never a serious
574        limitation, I suspect). However, there is a downside: pcre_compile() now
575        runs more slowly than before (30% or more, depending on the pattern). I
576        hope this isn't a big issue. There is no effect on runtime performance.
578    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
579        newline (only possible for the last line of a file) and it was a
580        pattern that set a locale (followed by /Lsomething), pcretest crashed.
582    19. Added additional timing features to pcretest. (1) The -tm option now times
583        matching only, not compiling. (2) Both -t and -tm can be followed, as a
584        separate command line item, by a number that specifies the number of
585        repeats to use when timing. The default is 50000; this gives better
586        precision, but takes uncomfortably long for very large patterns.
588    20. Extended pcre_study() to be more clever in cases where a branch of a
589        subpattern has no definite first character. For example, (a*|b*)[cd] would
590        previously give no result from pcre_study(). Now it recognizes that the
591        first character must be a, b, c, or d.
593    21. There was an incorrect error "recursive call could loop indefinitely" if
594        a subpattern (or the entire pattern) that was being tested for matching an
595        empty string contained only one non-empty item after a nested subpattern.
596        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
597        incorrectly, because the \d was being skipped in the check.
599    22. The pcretest program now has a new pattern option /B and a command line
600        option -b, which is equivalent to adding /B to every pattern. This causes
601        it to show the compiled bytecode, without the additional information that
602        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
603        is the same as /B/I).
605    23. A new optimization is now able automatically to treat some sequences such
606        as a*b as a*+b. More specifically, if something simple (such as a character
607        or a simple class like \d) has an unlimited quantifier, and is followed by
608        something that cannot possibly match the quantified thing, the quantifier
609        is automatically "possessified".
611    24. A recursive reference to a subpattern whose number was greater than 39
612        went wrong under certain circumstances in UTF-8 mode. This bug could also
613        have affected the operation of pcre_study().
615    25. Realized that a little bit of performance could be had by replacing
616        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
618    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
620    27. Possessive quantifiers such as a++ were previously implemented by turning
621        them into atomic groups such as ($>a+). Now they have their own opcodes,
622        which improves performance. This includes the automatically created ones
623        from 23 above.
625    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
626        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
627        the first matched character to be a colon. This applied both to named and
628        numbered groups.
630    29. The ucpinternal.h header file was missing its idempotency #ifdef.
632    30. I was sent a "project" file called libpcre.a.dev which I understand makes
633        building PCRE on Windows easier, so I have included it in the distribution.
635    31. There is now a check in pcretest against a ridiculously large number being
636        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
637        loop, the loop is abandoned.
639    32. Forward references to subpatterns in conditions such as (?(2)...) where
640        subpattern 2 is defined later cause pcre_compile() to search forwards in
641        the pattern for the relevant set of parentheses. This search went wrong
642        when there were unescaped parentheses in a character class, parentheses
643        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
645    33. "Subroutine" calls and backreferences were previously restricted to
646        referencing subpatterns earlier in the regex. This restriction has now
647        been removed.
649    34. Added a number of extra features that are going to be in Perl 5.10. On the
650        whole, these are just syntactic alternatives for features that PCRE had
651        previously implemented using the Python syntax or my own invention. The
652        other formats are all retained for compatibility.
654        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
655            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
656            also .NET compatible.
658        (b) A recursion or subroutine call to a named group can now be defined as
659            (?&name) as well as (?P>name).
661        (c) A backreference to a named group can now be defined as \k<name> or
662            \k'name' as well as (?P=name). The new forms, as well as being in Perl
663            5.10, are also .NET compatible.
665        (d) A conditional reference to a named group can now use the syntax
666            (?(<name>) or (?('name') as well as (?(name).
668        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
669            groups (named and numbered) that are never evaluated inline, but can be
670            called as "subroutines" from elsewhere. In effect, the DEFINE condition
671            is always false. There may be only one alternative in such a group.
673        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
674            as the simple (?(R). The condition is true only if the most recent
675            recursion is that of the given number or name. It does not search out
676            through the entire recursion stack.
678        (g) The escape \gN or \g{N} has been added, where N is a positive or
679            negative number, specifying an absolute or relative reference.
681    35. Tidied to get rid of some further signed/unsigned compiler warnings and
682        some "unreachable code" warnings.
684    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
685        things, this adds five new scripts.
687    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
688        There were also incompatibilities regarding the handling of \Q..\E inside
689        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
690        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
692    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
693        matches an empty string, and forcibly breaks the loop. There were bugs in
694        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
695        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
696        separate and independent bugs (that affected different cases) have been
697        fixed.
699    39. Refactored the code to abolish the use of different opcodes for small
700        capturing bracket numbers. This is a tidy that I avoided doing when I
701        removed the limit on the number of capturing brackets for 3.5 back in 2001.
702        The new approach is not only tidier, it makes it possible to reduce the
703        memory needed to fix the previous bug (38).
705    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
706        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
707        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
708        mode.
710    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
711        report.
713    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
714        copy construction and assignment in the C++ wrapper.
716    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
717        couple of bugs that could have given wrong results in the "--newline=crlf"
718        case.
720    44. Added a number of casts and did some reorganization of signed/unsigned int
721        variables following suggestions from Dair Grant. Also renamed the variable
722        "this" as "item" because it is a C++ keyword.
724    45. Arranged for dftables to add
726          #include "pcre_internal.h"
728        to pcre_chartables.c because without it, gcc 4.x may remove the array
729        definition from the final binary if PCRE is built into a static library and
730        dead code stripping is activated.
732    46. For an unanchored pattern, if a match attempt fails at the start of a
733        newline sequence, and the newline setting is CRLF or ANY, and the next two
734        characters are CRLF, advance by two characters instead of one.
737    Version 6.7 04-Jul-06
738    ---------------------
740     1. In order to handle tests when input lines are enormously long, pcretest has
741        been re-factored so that it automatically extends its buffers when
742        necessary. The code is crude, but this _is_ just a test program. The
743        default size has been increased from 32K to 50K.
745     2. The code in pcre_study() was using the value of the re argument before
746        testing it for NULL. (Of course, in any sensible call of the function, it
747        won't be NULL.)
749     3. The memmove() emulation function in pcre_internal.h, which is used on
750        systems that lack both memmove() and bcopy() - that is, hardly ever -
751        was missing a "static" storage class specifier.
753     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
754        containing an extended class (one that cannot be represented by a bitmap
755        because it contains high-valued characters or Unicode property items, e.g.
756        [\pZ]). Almost always one would set UTF-8 mode when processing such a
757        pattern, but PCRE should not loop if you do not (it no longer does).
758        [Detail: two cases were found: (a) a repeated subpattern containing an
759        extended class; (b) a recursive reference to a subpattern that followed a
760        previous extended class. It wasn't skipping over the extended class
761        correctly when UTF-8 mode was not set.]
763     5. A negated single-character class was not being recognized as fixed-length
764        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
765        compile error "lookbehind assertion is not fixed length".
767     6. The RunPerlTest auxiliary script was showing an unexpected difference
768        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
769        write a Perl script that can interpret lines of an input file either as
770        byte characters or as UTF-8, which is what "perltest" was being required to
771        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
772        can't do is switch easily at run time between having the "use utf8;" pragma
773        or not. In the end, I fudged it by using the RunPerlTest script to insert
774        "use utf8;" explicitly for the UTF-8 tests.
776     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
777        the end of the subject string, contrary to the documentation and to what
778        Perl does. This was true of both matching functions. Now it matches only at
779        the start of the subject and immediately after *internal* newlines.
781     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
782        a pointer to an int instead of a pointer to an unsigned long int. This
783        caused problems on 64-bit systems.
785     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
786        instance of the 'standard' template library not being so standard".
788    10. There was no check on the number of named subpatterns nor the maximum
789        length of a subpattern name. The product of these values is used to compute
790        the size of the memory block for a compiled pattern. By supplying a very
791        long subpattern name and a large number of named subpatterns, the size
792        computation could be caused to overflow. This is now prevented by limiting
793        the length of names to 32 characters, and the number of named subpatterns
794        to 10,000.
796    11. Subpatterns that are repeated with specific counts have to be replicated in
797        the compiled pattern. The size of memory for this was computed from the
798        length of the subpattern and the repeat count. The latter is limited to
799        65535, but there was no limit on the former, meaning that integer overflow
800        could in principle occur. The compiled length of a repeated subpattern is
801        now limited to 30,000 bytes in order to prevent this.
803    12. Added the optional facility to have named substrings with the same name.
805    13. Added the ability to use a named substring as a condition, using the
806        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
807        are numbers (not recommended). Forward references are permitted.
809    14. Added forward references in named backreferences (if you see what I mean).
811    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
812        pattern could run off the end of the subject. For example, the pattern
813        "(?s)(.{1,5})"8 did this with the subject "ab".
815    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
816        PCRE_CASELESS was set when matching characters that were quantified with ?
817        or *.
819    17. A character class other than a single negated character that had a minimum
820        but no maximum quantifier - for example [ab]{6,} - was not handled
821        correctly by pce_dfa_exec(). It would match only one character.
823    18. A valid (though odd) pattern that looked like a POSIX character
824        class but used an invalid character after [ (for example [[,abc,]]) caused
825        pcre_compile() to give the error "Failed: internal error: code overflow" or
826        in some cases to crash with a glibc free() error. This could even happen if
827        the pattern terminated after [[ but there just happened to be a sequence of
828        letters, a binary zero, and a closing ] in the memory that followed.
830    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
831        over the years. Originally (before any Unicode support), just the bottom 8
832        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
833        output from "man perlunicode" includes this:
835          The regular expression compiler produces polymorphic opcodes.  That
836          is, the pattern adapts to the data and automatically switches to
837          the Unicode character scheme when presented with Unicode data--or
838          instead uses a traditional byte scheme when presented with byte
839          data.
841        Sadly, a wide octal escape does not cause a switch, and in a string with
842        no other multibyte characters, these octal escapes are treated as before.
843        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
844        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
845        Unicode string.
847        I have not perpetrated such confusion in PCRE. Up till now, it took just
848        the bottom 8 bits, as in old Perl. I have now made octal escapes with
849        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
850        translate to the appropriate multibyte character.
852    29. Applied some refactoring to reduce the number of warnings from Microsoft
853        and Borland compilers. This has included removing the fudge introduced
854        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
855        a warning about an unused variable.
857    21. PCRE has not included VT (character 0x0b) in the set of whitespace
858        characters since release 4.0, because Perl (from release 5.004) does not.
859        [Or at least, is documented not to: some releases seem to be in conflict
860        with the documentation.] However, when a pattern was studied with
861        pcre_study() and all its branches started with \s, PCRE still included VT
862        as a possible starting character. Of course, this did no harm; it just
863        caused an unnecessary match attempt.
865    22. Removed a now-redundant internal flag bit that recorded the fact that case
866        dependency changed within the pattern. This was once needed for "required
867        byte" processing, but is no longer used. This recovers a now-scarce options
868        bit. Also moved the least significant internal flag bit to the most-
869        significant bit of the word, which was not previously used (hangover from
870        the days when it was an int rather than a uint) to free up another bit for
871        the future.
873    23. Added support for CRLF line endings as well as CR and LF. As well as the
874        default being selectable at build time, it can now be changed at runtime
875        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
876        specify that it is scanning data with non-default line endings.
878    24. Changed the definition of CXXLINK to make it agree with the definition of
879        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
881    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
882        recursions. This makes a big different to stack usage for some patterns.
884    26. If a subpattern containing a named recursion or subroutine reference such
885        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
886        the space required for the compiled pattern went wrong and gave too small a
887        value. Depending on the environment, this could lead to "Failed: internal
888        error: code overflow at offset 49" or "glibc detected double free or
889        corruption" errors.
891    27. Applied patches from Google (a) to support the new newline modes and (b) to
892        advance over multibyte UTF-8 characters in GlobalReplace.
894    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
895        difference for some implementation of PCRE in some Windows version.
897    29. Added some extra testing facilities to pcretest:
899        \q<number>   in a data line sets the "match limit" value
900        \Q<number>   in a data line sets the "match recursion limt" value
901        -S <number>  sets the stack size, where <number> is in megabytes
903        The -S option isn't available for Windows.
906    Version 6.6 06-Feb-06
907    ---------------------
909     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
910        in pcreposix.h. I have copied the definition from pcre.h.
912     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
913        because pcre.h is no longer a built file.
915     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
916        not normally included in the compiled code.
919    Version 6.5 01-Feb-06
920    ---------------------
922     1. When using the partial match feature with pcre_dfa_exec(), it was not
923        anchoring the second and subsequent partial matches at the new starting
924        point. This could lead to incorrect results. For example, with the pattern
925        /1234/, partially matching against "123" and then "a4" gave a match.
927     2. Changes to pcregrep:
929        (a) All non-match returns from pcre_exec() were being treated as failures
930            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
931            error message is output. Some extra information is given for the
932            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
933            probably the only errors that are likely to be caused by users (by
934            specifying a regex that has nested indefinite repeats, for instance).
935            If there are more than 20 of these errors, pcregrep is abandoned.
937        (b) A binary zero was treated as data while matching, but terminated the
938            output line if it was written out. This has been fixed: binary zeroes
939            are now no different to any other data bytes.
941        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
942            used to set a locale for matching. The --locale=xxxx long option has
943            been added (no short equivalent) to specify a locale explicitly on the
944            pcregrep command, overriding the environment variables.
946        (d) When -B was used with -n, some line numbers in the output were one less
947            than they should have been.
949        (e) Added the -o (--only-matching) option.
951        (f) If -A or -C was used with -c (count only), some lines of context were
952            accidentally printed for the final match.
954        (g) Added the -H (--with-filename) option.
956        (h) The combination of options -rh failed to suppress file names for files
957            that were found from directory arguments.
959        (i) Added the -D (--devices) and -d (--directories) options.
961        (j) Added the -F (--fixed-strings) option.
963        (k) Allow "-" to be used as a file name for -f as well as for a data file.
965        (l) Added the --colo(u)r option.
967        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
968            is not present by default.
970     3. A nasty bug was discovered in the handling of recursive patterns, that is,
971        items such as (?R) or (?1), when the recursion could match a number of
972        alternatives. If it matched one of the alternatives, but subsequently,
973        outside the recursion, there was a failure, the code tried to back up into
974        the recursion. However, because of the way PCRE is implemented, this is not
975        possible, and the result was an incorrect result from the match.
977        In order to prevent this happening, the specification of recursion has
978        been changed so that all such subpatterns are automatically treated as
979        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
981     4. I had overlooked the fact that, in some locales, there are characters for
982        which isalpha() is true but neither isupper() nor islower() are true. In
983        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
984        and ordfeminine) are like this. This affected the treatment of \w and \W
985        when they appeared in character classes, but not when they appeared outside
986        a character class. The bit map for "word" characters is now created
987        separately from the results of isalnum() instead of just taking it from the
988        upper, lower, and digit maps. (Plus the underscore character, of course.)
990     5. The above bug also affected the handling of POSIX character classes such as
991        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
992        permanent tables. Instead, the bit maps for such a class were previously
993        created as the appropriate unions of the upper, lower, and digit bitmaps.
994        Now they are created by subtraction from the [[:word:]] class, which has
995        its own bitmap.
997     6. The [[:blank:]] character class matches horizontal, but not vertical space.
998        It is created by subtracting the vertical space characters (\x09, \x0a,
999        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1000        subtraction was done in the overall bitmap for a character class, meaning
1001        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1002        be recognized. This bug has been fixed.
1004     7. Patches from the folks at Google:
1006          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1007          real life, but is still worth protecting against".
1009          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1010          regular expressions".
1012          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1013          have it.
1015          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1016          "configure" and the latter not, in order to fix a problem somebody had
1017          with compiling the Arg class on HP-UX.
1019          (e) Improve the error-handling of the C++ wrapper a little bit.
1021          (f) New tests for checking recursion limiting.
1023     8. The pcre_memmove() function, which is used only if the environment does not
1024        have a standard memmove() function (and is therefore rarely compiled),
1025        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1026        returning a result (though PCRE never actually uses the result).
1028     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1029        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1030        returned instead of calling malloc() with an overflowing number that would
1031        most likely cause subsequent chaos.
1033    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1035    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1036        with this option is matched, the nmatch and pmatch options of regexec() are
1037        ignored.
1039    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1040        provided in case anyone wants to the the POSIX interface with UTF-8
1041        strings.
1043    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1044        C++ linking (needed for some HP-UX environments).
1046    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1047        (unused parameter) and in the pcre_printint() function (omitted "default"
1048        switch label when the default is to do nothing).
1050    15. Added some code to make it possible, when PCRE is compiled as a C++
1051        library, to replace subject pointers for pcre_exec() with a smart pointer
1052        class, thus making it possible to process discontinuous strings.
1054    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1055        much the same function. They were added by different people who were trying
1056        to make PCRE easy to compile on non-Unix systems. It has been suggested
1057        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1058        for compiling on Windows systems. I have therefore replaced it with
1059        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1060        defaults to "extern" for C or "extern C" for C++, which works fine on
1061        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1062        SCOPE with something explicit in config.h. In addition:
1064        (a) pcreposix.h still had just "extern" instead of either of these macros;
1065            I have replaced it with PCRE_DATA_SCOPE.
1067        (b) Functions such as _pcre_xclass(), which are internal to the library,
1068            but external in the C sense, all had PCRE_EXPORT in their definitions.
1069            This is apparently wrong for the Windows case, so I have removed it.
1070            (It makes no difference on Unix-like systems.)
1072    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1073        of recursive calls to match(). This is different to MATCH_LIMIT because
1074        that limits the total number of calls to match(), not all of which increase
1075        the depth of recursion. Limiting the recursion depth limits the amount of
1076        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1077        when PCRE is compiled, and changed at run time. A patch from Google adds
1078        this functionality to the C++ interface.
1080    18. Changes to the handling of Unicode character properties:
1082        (a) Updated the table to Unicode 4.1.0.
1084        (b) Recognize characters that are not in the table as "Cn" (undefined).
1086        (c) I revised the way the table is implemented to a much improved format
1087            which includes recognition of ranges. It now supports the ranges that
1088            are defined in UnicodeData.txt, and it also amalgamates other
1089            characters into ranges. This has reduced the number of entries in the
1090            table from around 16,000 to around 3,000, thus reducing its size
1091            considerably. I realized I did not need to use a tree structure after
1092            all - a binary chop search is just as efficient. Having reduced the
1093            number of entries, I extended their size from 6 bytes to 8 bytes to
1094            allow for more data.
1096        (d) Added support for Unicode script names via properties such as \p{Han}.
1098    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1099        matching that character.
1101    20. When matching a repeated Unicode property with a minimum greater than zero,
1102        (for example \pL{2,}), PCRE could look past the end of the subject if it
1103        reached it while seeking the minimum number of characters. This could
1104        happen only if some of the characters were more than one byte long, because
1105        there is a check for at least the minimum number of bytes.
1107    21. Refactored the implementation of \p and \P so as to be more general, to
1108        allow for more different types of property in future. This has changed the
1109        compiled form incompatibly. Anybody with saved compiled patterns that use
1110        \p or \P will have to recompile them.
1112    22. Added "Any" and "L&" to the supported property types.
1114    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1115        but give a compile time error if the value is greater than 0xff.
1117    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1118        accidentally not being installed or uninstalled.
1120    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1121        made were to insert the current release number. This seemed silly, because
1122        it made things harder for people building PCRE on systems that don't run
1123        "configure". I have turned pcre.h into a distributed file, no longer built
1124        by "configure", with the version identification directly included. There is
1125        no longer a pcre.h.in file.
1127        However, this change necessitated a change to the pcre-config script as
1128        well. It is built from pcre-config.in, and one of the substitutions was the
1129        release number. I have updated configure.ac so that ./configure now finds
1130        the release number by grepping pcre.h.
1132    26. Added the ability to run the tests under valgrind.
1135    Version 6.4 05-Sep-05
1136    ---------------------
1138     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1139        "--" to be printed when multiple files were scanned, even when none of the
1140        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1141        consider it to be a bug, and have restored the previous behaviour.
1143     2. A couple of code tidies to get rid of compiler warnings.
1145     3. The pcretest program used to cheat by referring to symbols in the library
1146        whose names begin with _pcre_. These are internal symbols that are not
1147        really supposed to be visible externally, and in some environments it is
1148        possible to suppress them. The cheating is now confined to including
1149        certain files from the library's source, which is a bit cleaner.
1151     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1152        file's purpose clearer.
1154     5. Reorganized pcre_ucp_findchar().
1157    Version 6.3 15-Aug-05
1158    ---------------------
1160     1. The file libpcre.pc.in did not have general read permission in the tarball.
1162     2. There were some problems when building without C++ support:
1164        (a) If C++ support was not built, "make install" and "make test" still
1165            tried to test it.
1167        (b) There were problems when the value of CXX was explicitly set. Some
1168            changes have been made to try to fix these, and ...
1170        (c) --disable-cpp can now be used to explicitly disable C++ support.
1172        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1173            backslash in a target when C++ was disabled. This confuses some
1174            versions of "make", apparently. Using an intermediate variable solves
1175            this. (Same for CPP_LOBJ.)
1177     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1178        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1179        necessary on certain architectures.
1181     4. Added a setting of -export-symbols-regex to the link command to remove
1182        those symbols that are exported in the C sense, but actually are local
1183        within the library, and not documented. Their names all begin with
1184        "_pcre_". This is not a perfect job, because (a) we have to except some
1185        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1186        available (and never for static libraries). I have made a note to try to
1187        find a way round (a) in the future.
1190    Version 6.2 01-Aug-05
1191    ---------------------
1193     1. There was no test for integer overflow of quantifier values. A construction
1194        such as {1111111111111111} would give undefined results. What is worse, if
1195        a minimum quantifier for a parenthesized subpattern overflowed and became
1196        negative, the calculation of the memory size went wrong. This could have
1197        led to memory overwriting.
1199     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1201     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1202        operating environments where this matters.
1204     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1205        PCRE options from within the C++ wrapper.
1207     5. Named capturing subpatterns were not being correctly counted when a pattern
1208        was compiled. This caused two problems: (a) If there were more than 100
1209        such subpatterns, the calculation of the memory needed for the whole
1210        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1211        back references of the form \12, where the number was greater than 9, were
1212        not recognized as back references, even though there were sufficient
1213        previous subpatterns.
1215     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1216        versions of gcc, e.g. 2.95.4.
1219    Version 6.1 21-Jun-05
1220    ---------------------
1222     1. There was one reference to the variable "posix" in pcretest.c that was not
1223        surrounded by "#if !defined NOPOSIX".
1225     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1226        the cross-check on the old pcre_info() function, for the benefit of the
1227        cut-down version of PCRE that is currently imported into Exim.
1229     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1230        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1231        patterns that start (?i) but I don't think that matters. The use of (?i) is
1232        just an example; this all applies to the other options as well.
1234     4. Since libtool seems to echo the compile commands it is issuing, the output
1235        from "make" can be reduced a bit by putting "@" in front of each libtool
1236        compile command.
1238     5. Patch from the folks at Google for configure.in to be a bit more thorough
1239        in checking for a suitable C++ installation before trying to compile the
1240        C++ stuff. This should fix a reported problem when a compiler was present,
1241        but no suitable headers.
1243     6. The man pages all had just "PCRE" as their title. I have changed them to
1244        be the relevant file name. I have also arranged that these names are
1245        retained in the file doc/pcre.txt, which is a concatenation in text format
1246        of all the man pages except the little individual ones for each function.
1248     7. The NON-UNIX-USE file had not been updated for the different set of source
1249        files that come with release 6. I also added a few comments about the C++
1250        wrapper.
1253    Version 6.0 07-Jun-05
1254    ---------------------
1256     1. Some minor internal re-organization to help with my DFA experiments.
1258     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1259        didn't matter for the library itself when fully configured, but did matter
1260        when compiling without UCP support, or within Exim, where the ucp files are
1261        not imported.
1263     3. Refactoring of the library code to split up the various functions into
1264        different source modules. The addition of the new DFA matching code (see
1265        below) to a single monolithic source would have made it really too
1266        unwieldy, quite apart from causing all the code to be include in a
1267        statically linked application, when only some functions are used. This is
1268        relevant even without the DFA addition now that patterns can be compiled in
1269        one application and matched in another.
1271        The downside of splitting up is that there have to be some external
1272        functions and data tables that are used internally in different modules of
1273        the library but which are not part of the API. These have all had their
1274        names changed to start with "_pcre_" so that they are unlikely to clash
1275        with other external names.
1277     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1278        a different (DFA) algorithm. Although it is slower than the original
1279        function, it does have some advantages for certain types of matching
1280        problem.
1282     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1283        including restarting after a partial match.
1285     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1286        defined when compiling for Windows was sent to me. I have put it into the
1287        code, though I have no means of testing or verifying it.
1289     7. Added the pcre_refcount() auxiliary function.
1291     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1292        match before or at the first newline in the subject string. In pcretest,
1293        the /f option on a pattern can be used to set this.
1295     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1296        would behave wrongly. This has been present in PCRE since release 4.0.
1298    10. A number of changes to the pcregrep command:
1300        (a) Refactored how -x works; insert ^(...)$ instead of setting
1301            PCRE_ANCHORED and checking the length, in preparation for adding
1302            something similar for -w.
1304        (b) Added the -w (match as a word) option.
1306        (c) Refactored the way lines are read and buffered so as to have more
1307            than one at a time available.
1309        (d) Implemented a pcregrep test script.
1311        (e) Added the -M (multiline match) option. This allows patterns to match
1312            over several lines of the subject. The buffering ensures that at least
1313            8K, or the rest of the document (whichever is the shorter) is available
1314            for matching (and similarly the previous 8K for lookbehind assertions).
1316        (f) Changed the --help output so that it now says
1318              -w, --word-regex(p)
1320            instead of two lines, one with "regex" and the other with "regexp"
1321            because that confused at least one person since the short forms are the
1322            same. (This required a bit of code, as the output is generated
1323            automatically from a table. It wasn't just a text change.)
1325        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1326            option but starts with a hyphen. Could be a pattern or a path name
1327            starting with a hyphen, for instance.
1329        (h) "-" can be given as a file name to represent stdin.
1331        (i) When file names are being printed, "(standard input)" is used for
1332            the standard input, for compatibility with GNU grep. Previously
1333            "<stdin>" was used.
1335        (j) The option --label=xxx can be used to supply a name to be used for
1336            stdin when file names are being printed. There is no short form.
1338        (k) Re-factored the options decoding logic because we are going to add
1339            two more options that take data. Such options can now be given in four
1340            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1342        (l) Added the -A, -B, and -C options for requesting that lines of context
1343            around matches be printed.
1345        (m) Added the -L option to print the names of files that do not contain
1346            any matching lines, that is, the complement of -l.
1348        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1349            continue to scan other files.
1351        (o) The -s option was incorrectly implemented. For compatibility with other
1352            greps, it now suppresses the error message for a non-existent or non-
1353            accessible file (but not the return code). There is a new option called
1354            -q that suppresses the output of matching lines, which was what -s was
1355            previously doing.
1357        (p) Added --include and --exclude options to specify files for inclusion
1358            and exclusion when recursing.
1360    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1361        Hopefully, it now does.
1363    12. Missing cast in pcre_study().
1365    13. Added an "uninstall" target to the makefile.
1367    14. Replaced "extern" in the function prototypes in Makefile.in with
1368        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1369        world, but is set differently for Windows.
1371    15. Added a second compiling function called pcre_compile2(). The only
1372        difference is that it has an extra argument, which is a pointer to an
1373        integer error code. When there is a compile-time failure, this is set
1374        non-zero, in addition to the error test pointer being set to point to an
1375        error message. The new argument may be NULL if no error number is required
1376        (but then you may as well call pcre_compile(), which is now just a
1377        wrapper). This facility is provided because some applications need a
1378        numeric error indication, but it has also enabled me to tidy up the way
1379        compile-time errors are handled in the POSIX wrapper.
1381    16. Added VPATH=.libs to the makefile; this should help when building with one
1382        prefix path and installing with another. (Or so I'm told by someone who
1383        knows more about this stuff than I do.)
1385    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1386        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1387        match everything, including newlines. This is not POSIX-compatible, but
1388        somebody wanted the feature. From pcretest it can be activated by using
1389        both the P and the s flags.
1391    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1393    19. libpcre.pc was being incorrectly installed as executable.
1395    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1396        it now also looks for '\r' so that it will work unmodified on Windows.
1398    21. Added Google's contributed C++ wrapper to the distribution.
1400    22. Added some untidy missing memory free() calls in pcretest, to keep
1401        Electric Fence happy when testing.
1405    Version 5.0 13-Sep-04
1406    ---------------------
1408     1. Internal change: literal characters are no longer packed up into items
1409        containing multiple characters in a single byte-string. Each character
1410        is now matched using a separate opcode. However, there may be more than one
1411        byte in the character in UTF-8 mode.
1413     2. The pcre_callout_block structure has two new fields: pattern_position and
1414        next_item_length. These contain the offset in the pattern to the next match
1415        item, and its length, respectively.
1417     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1418        insertion of callouts before each pattern item. Added the /C option to
1419        pcretest to make use of this.
1421     4. On the advice of a Windows user, the lines
1423          #if defined(_WIN32) || defined(WIN32)
1424          _setmode( _fileno( stdout ), 0x8000 );
1425          #endif  /* defined(_WIN32) || defined(WIN32) */
1427        have been added to the source of pcretest. This apparently does useful
1428        magic in relation to line terminators.
1430     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1431        for the benefit of those environments where the "b" makes a difference.
1433     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1434        to know about it. I have put a hack into configure.in that adds in code
1435        to set GCC=yes if CC=icc. This seems to end up at a point in the
1436        generated configure script that is early enough to affect the setting of
1437        compiler options, which is what is needed, but I have no means of testing
1438        whether it really works. (The user who reported this had patched the
1439        generated configure script, which of course I cannot do.)
1441        LATER: After change 22 below (new libtool files), the configure script
1442        seems to know about icc (and also ecc). Therefore, I have commented out
1443        this hack in configure.in.
1445     7. Added support for pkg-config (2 patches were sent in).
1447     8. Negated POSIX character classes that used a combination of internal tables
1448        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1449        [[:^ascii]]. Typically, they would match almost any characters. The other
1450        POSIX classes were not broken in this way.
1452     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1453        to find the match, as PCRE was deluded into thinking that the match had to
1454        start at the start point or following a newline. The same bug applied to
1455        patterns with negative forward assertions or any backward assertions
1456        preceding ".*" at the start, unless the pattern required a fixed first
1457        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1459    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1460        starting at the last subject character, bytes beyond the end of the subject
1461        string were read.
1463    11. Renamed the variable "class" as "classbits" to make life easier for C++
1464        users. (Previously there was a macro definition, but it apparently wasn't
1465        enough.)
1467    12. Added the new field "tables" to the extra data so that tables can be passed
1468        in at exec time, or the internal tables can be re-selected. This allows
1469        a compiled regex to be saved and re-used at a later time by a different
1470        program that might have everything at different addresses.
1472    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1473        -R library as well as a -L library.
1475    14. The debugging options of pcretest (-d on the command line or D on a
1476        pattern) showed incorrect output for anything following an extended class
1477        that contained multibyte characters and which was followed by a quantifier.
1479    15. Added optional support for general category Unicode character properties
1480        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1481        support. It adds about 90K to the size of the library. The meanings of the
1482        inbuilt class escapes such as \d and \s have NOT been changed.
1484    16. Updated pcredemo.c to include calls to free() to release the memory for the
1485        compiled pattern.
1487    17. The generated file chartables.c was being created in the source directory
1488        instead of in the building directory. This caused the build to fail if the
1489        source directory was different from the building directory, and was
1490        read-only.
1492    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1493        file. No doubt somebody will tell me if they don't make sense... Also added
1494        Dan Mooney's comments about building on OpenVMS.
1496    19. Added support for partial matching via the PCRE_PARTIAL option for
1497        pcre_exec() and the \P data escape in pcretest.
1499    20. Extended pcretest with 3 new pattern features:
1501        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1502              write the compiled pattern to the file whose name is "rest-of-line".
1503              This is a straight binary dump of the data, with the saved pointer to
1504              the character tables forced to be NULL. The study data, if any, is
1505              written too. After writing, pcretest reads a new pattern.
1507        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1508              compiled pattern from the given file. There must not be any
1509              occurrences of "<" in the file name (pretty unlikely); if there are,
1510              pcretest will instead treat the initial "<" as a pattern delimiter.
1511              After reading in the pattern, pcretest goes on to read data lines as
1512              usual.
1514        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1515              and 16-bit fields in a compiled pattern, to simulate a pattern that
1516              was compiled on a host of opposite endianness.
1518    21. The pcre-exec() function can now cope with patterns that were compiled on
1519        hosts of opposite endianness, with this restriction:
1521          As for any compiled expression that is saved and used later, the tables
1522          pointer field cannot be preserved; the extra_data field in the arguments
1523          to pcre_exec() should be used to pass in a tables address if a value
1524          other than the default internal tables were used at compile time.
1526    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1527        now diagnosed as an error. Previously, most of the time, a negative number
1528        would have been treated as zero, but if in addition "ovector" was passed as
1529        NULL, a crash could occur.
1531    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1532        new versions from the libtool 1.5 distribution (the last one is a copy of
1533        a file called libtool.m4). This seems to have fixed the need to patch
1534        "configure" to support Darwin 1.3 (which I used to do). However, I still
1535        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1536        workstation).
1538    24. Changed the PCRE licence to be the more standard "BSD" licence.
1541    Version 4.5 01-Dec-03
1542    ---------------------
1544     1. There has been some re-arrangement of the code for the match() function so
1545        that it can be compiled in a version that does not call itself recursively.
1546        Instead, it keeps those local variables that need separate instances for
1547        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1548        needs to "recurse". Keeping track of where control must go is done by means
1549        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1550        hide most of the details from the main code, and operates only if
1551        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1552        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1553        operating.
1555        To make it easier for callers to provide specially tailored get/free
1556        functions for this usage, two new functions, pcre_stack_malloc, and
1557        pcre_stack_free, are used. They are always called in strict stacking order,
1558        and the size of block requested is always the same.
1560        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1561        PCRE has been compiled to use the stack or the heap for recursion. The
1562        -C option of pcretest uses this to show which version is compiled.
1564        A new data escape \S, is added to pcretest; it causes the amounts of store
1565        obtained and freed by both kinds of malloc/free at match time to be added
1566        to the output.
1568     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1569        what's available on my current Linux desktop machine.
1571     3. When matching a UTF-8 string, the test for a valid string at the start has
1572        been extended. If start_offset is not zero, PCRE now checks that it points
1573        to a byte that is the start of a UTF-8 character. If not, it returns
1574        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1575        this is necessary because there may be backward assertions in the pattern.
1576        When matching the same subject several times, it may save resources to use
1577        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1579     4. The code for checking the validity of UTF-8 strings has been tightened so
1580        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1581        containing "overlong sequences".
1583     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1584        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1585        should have been "&", but it just so happened that all the cases this let
1586        through by mistake were picked up later in the function.
1588     6. I had used a variable called "isblank" - this is a C99 function, causing
1589        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1591     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1592        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1593        so the version is shown; (c) stop "make test" echoing "./RunTest".
1595     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1597     9. The prototype for memmove() for systems that don't have it was using
1598        size_t, but the inclusion of the header that defines size_t was later. I've
1599        moved the #includes for the C headers earlier to avoid this.
1601    10. Added some adjustments to the code to make it easier to compiler on certain
1602        special systems:
1604          (a) Some "const" qualifiers were missing.
1605          (b) Added the macro EXPORT before all exported functions; by default this
1606              is defined to be empty.
1607          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1608              that it reads its output file name as an argument instead of writing
1609              to the standard output and assuming this can be redirected.
1611    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1612        class containing characters with values greater than 255, PCRE compilation
1613        went into a loop.
1615    12. A recursive reference to a subpattern that was within another subpattern
1616        that had a minimum quantifier of zero caused PCRE to crash. For example,
1617        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1618        recursion. If the recursively-called subpattern itself had a zero repeat,
1619        that was OK.
1621    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1622        buffer into which it was copied (for escape processing) was still set at
1623        1024, so long lines caused crashes.
1625    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1626        "internal error: code overflow...". This applied to any character class
1627        that was followed by a possessive quantifier.
1629    15. Modified the Makefile to add libpcre.la as a prerequisite for
1630        libpcreposix.la because I was told this is needed for a parallel build to
1631        work.
1633    16. If a pattern that contained .* following optional items at the start was
1634        studied, the wrong optimizing data was generated, leading to matching
1635        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1636        matching string must start with a or b or c. The correct conclusion for
1637        this pattern is that a match can start with any character.
1640    Version 4.4 13-Aug-03
1641    ---------------------
1643     1. In UTF-8 mode, a character class containing characters with values between
1644        127 and 255 was not handled correctly if the compiled pattern was studied.
1645        In fixing this, I have also improved the studying algorithm for such
1646        classes (slightly).
1648     2. Three internal functions had redundant arguments passed to them. Removal
1649        might give a very teeny performance improvement.
1651     3. Documentation bug: the value of the capture_top field in a callout is *one
1652        more than* the number of the hightest numbered captured substring.
1654     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1655        in incorrectly linking with a previously installed version. They now link
1656        explicitly with libpcre.la.
1658     5. configure.in no longer needs to recognize Cygwin specially.
1660     6. A problem in pcre.in for Windows platforms is fixed.
1662     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1663        pcretest, it used to include the size of the study block as part of its
1664        output. Unfortunately, the structure contains a field that has a different
1665        size on different hardware architectures. This meant that the tests that
1666        showed this size failed. As the block is currently always of a fixed size,
1667        this information isn't actually particularly useful in pcretest output, so
1668        I have just removed it.
1670     8. Three pre-processor statements accidentally did not start in column 1.
1671        Sadly, there are *still* compilers around that complain, even though
1672        standard C has not required this for well over a decade. Sigh.
1674     9. In pcretest, the code for checking callouts passed small integers in the
1675        callout_data field, which is a void * field. However, some picky compilers
1676        complained about the casts involved for this on 64-bit systems. Now
1677        pcretest passes the address of the small integer instead, which should get
1678        rid of the warnings.
1680    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1681        both compile and run time, and gives an error if an invalid UTF-8 sequence
1682        is found. There is a option for disabling this check in cases where the
1683        string is known to be correct and/or the maximum performance is wanted.
1685    11. In response to a bug report, I changed one line in Makefile.in from
1687            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1688        to
1689            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1691        to look similar to other lines, but I have no way of telling whether this
1692        is the right thing to do, as I do not use Windows. No doubt I'll get told
1693        if it's wrong...
1696    Version 4.3 21-May-03
1697    ---------------------
1699    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1700       Makefile.
1702    2. Some refactoring to improve the quality of the code:
1704       (i)   The utf8_table... variables are now declared "const".
1706       (ii)  The code for \cx, which used the "case flipping" table to upper case
1707             lower case letters, now just substracts 32. This is ASCII-specific,
1708             but the whole concept of \cx is ASCII-specific, so it seems
1709             reasonable.
1711       (iii) PCRE was using its character types table to recognize decimal and
1712             hexadecimal digits in the pattern. This is silly, because it handles
1713             only 0-9, a-f, and A-F, but the character types table is locale-
1714             specific, which means strange things might happen. A private
1715             table is now used for this - though it costs 256 bytes, a table is
1716             much faster than multiple explicit tests. Of course, the standard
1717             character types table is still used for matching digits in subject
1718             strings against \d.
1720       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1721             ending in _t are). So I've renamed it as ESC_tee.
1723    3. The first argument for regexec() in the POSIX wrapper should have been
1724       defined as "const".
1726    4. Changed pcretest to use malloc() for its buffers so that they can be
1727       Electric Fenced for debugging.
1729    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1730       to read one or more bytes before the start of the subject string. Often this
1731       had no effect on PCRE's behaviour, but in some circumstances it could
1732       provoke a segmentation fault.
1734    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1735       to try to read one or more bytes before the start of the subject string.
1737    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1738       UTF-8 support could misbehave in various ways if the subject string
1739       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1740       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1741       back over UTF-8 characters.)
1744    Version 4.2 14-Apr-03
1745    ---------------------
1747    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1749    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1750         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1751         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1752         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1753         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1754           and BUILD_EXEEXT
1755         Note: automatic setting of the BUILD variables is not yet working
1756         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1757           compile-time but not at link-time
1758         [LINK]: use for linking executables only
1759         make different versions for Windows and non-Windows
1760         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1761           libraries
1762         [LINK_FOR_BUILD]: new variable
1763         [OBJEXT]: use throughout
1764         [EXEEXT]: use throughout
1765         <winshared>: new target
1766         <wininstall>: new target
1767         <dftables.o>: use native compiler
1768         <dftables>: use native linker
1769         <install>: handle Windows platform correctly
1770         <clean>: ditto
1771         <check>: ditto
1772         copy DLL to top builddir before testing
1774       As part of these changes, -no-undefined was removed again. This was reported
1775       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1776       in any case.
1778    3. Some tidies to get rid of compiler warnings:
1780       . In the match_data structure, match_limit was an unsigned long int, whereas
1781         match_call_count was an int. I've made them both unsigned long ints.
1783       . In pcretest the fact that a const uschar * doesn't automatically cast to
1784         a void * provoked a warning.
1786       . Turning on some more compiler warnings threw up some "shadow" variables
1787         and a few more missing casts.
1789    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1790       option, a class that contained a single character with a value between 128
1791       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1793    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1794       option, a class that contained several characters, but with at least one
1795       whose value was between 128 and 255 caused PCRE to crash.
1798    Version 4.1 12-Mar-03
1799    ---------------------
1801    1. Compiling with gcc -pedantic found a couple of places where casts were
1802    needed, and a string in dftables.c that was longer than standard compilers are
1803    required to support.
1805    2. Compiling with Sun's compiler found a few more places where the code could
1806    be tidied up in order to avoid warnings.
1808    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1809    first of these names is deprecated in the latest Autoconf in favour of the name
1810    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1811    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1812    analogy I have changed it to CFLAGS_FOR_BUILD.
1814    4. Added -no-undefined to the linking command in the Makefile, because this is
1815    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1816    linking step for the pcreposix library.
1818    5. PCRE was failing to diagnose the case of two named groups with the same
1819    name.
1821    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1822    literal character that is needed in the subject for a match, and scans along to
1823    ensure that it is present before embarking on the full matching process. This
1824    saves time in cases of nested unlimited repeats that are never going to match.
1825    Problem: the scan can take a lot of time if the subject is very long (e.g.
1826    megabytes), thus penalizing straightforward matches. It is now done only if the
1827    amount of subject to be scanned is less than 1000 bytes.
1829    7. A lesser problem with the same optimization is that it was recording the
1830    first character of an anchored pattern as "needed", thus provoking a search
1831    right along the subject, even when the first match of the pattern was going to
1832    fail. The "needed" character is now not set for anchored patterns, unless it
1833    follows something in the pattern that is of non-fixed length. Thus, it still
1834    fulfils its original purpose of finding quick non-matches in cases of nested
1835    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1838    Version 4.0 17-Feb-03
1839    ---------------------
1841    1. If a comment in an extended regex that started immediately after a meta-item
1842    extended to the end of string, PCRE compiled incorrect data. This could lead to
1843    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1845    2. Moved to autoconf 2.53 and libtool 1.4.2.
1847    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1848    the special perltest8 script is no longer needed - all the tests can be run
1849    from a single perltest script.
1851    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1852    by \s. It has now been removed in PCRE. This means it isn't recognized as
1853    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1854    class [:space:] *does* include VT, thereby creating a mess.
1856    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1857    space and tab.
1859    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1860    its new features into the main test script, reducing the number of scripts.
1862    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1863    were backward compatible, and made the (?i) apply to the whole pattern, as if
1864    /i were given. Now it behaves more logically, and applies the option setting
1865    only to what follows. PCRE has been changed to follow suit. However, if it
1866    finds options settings right at the start of the pattern, it extracts them into
1867    the global options, as before. Thus, they show up in the info data.
1869    8. Added support for the \Q...\E escape sequence. Characters in between are
1870    treated as literals. This is slightly different from Perl in that $ and @ are
1871    also handled as literals inside the quotes. In Perl, they will cause variable
1872    interpolation. Note the following examples:
1874        Pattern            PCRE matches      Perl matches
1876        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1877        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1878        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1880    For compatibility with Perl, \Q...\E sequences are recognized inside character
1881    classes as well as outside them.
1883    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1884    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1885    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1886    signed/unsigned warnings.
1888    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1889    option for pcretest, so I've replaced it by a simple function that does just
1890    that job.
1892    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1893    "pcregrep -".
1895    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1896    Java package. This provides some syntactic sugar for simple cases of what my
1897    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1898    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1899    item, you can use this simplified notation. Note that only makes sense with
1900    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1901    greediness, whatever the setting of the PCRE_UNGREEDY option.
1903    13. A change of greediness default within a pattern was not taking effect at
1904    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1905    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1906    was abstracted outside.
1908    14. PCRE now supports the \G assertion. It is true when the current matching
1909    position is at the start point of the match. This differs from \A when the
1910    starting offset is non-zero. Used with the /g option of pcretest (or similar
1911    code), it works in the same way as it does for Perl's /g option. If all
1912    alternatives of a regex begin with \G, the expression is anchored to the start
1913    match position, and the "anchored" flag is set in the compiled expression.
1915    15. Some bugs concerning the handling of certain option changes within patterns
1916    have been fixed. These applied to options other than (?ims). For example,
1917    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1918    been the other way round. Some of this was related to change 7 above.
1920    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1921    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1922    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1923    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1925    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1926    mode. Unlike ".", it always matches newline, whatever the setting of
1927    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1928    assertions. Perl allows it, but it doesn't (in general) work because it can't
1929    calculate the length of the lookbehind. At least, that's the case for Perl
1930    5.8.0 - I've been told they are going to document that it doesn't work in
1931    future.
1933    18. Added an error diagnosis for escapes that PCRE does not support: these are
1934    \L, \l, \N, \P, \p, \U, \u, and \X.
1936    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1937    reading past the end of the pattern in cases such as /[abcd/.
1939    20. PCRE was getting more memory than necessary for patterns with classes that
1940    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1942    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1943    compiling PCRE for use with Virtual Pascal.
1945    22. Small fix to the Makefile to make it work properly if the build is done
1946    outside the source tree.
1948    23. Added a new extension: a condition to go with recursion. If a conditional
1949    subpattern starts with (?(R) the "true" branch is used if recursion has
1950    happened, whereas the "false" branch is used only at the top level.
1952    24. When there was a very long string of literal characters (over 255 bytes
1953    without UTF support, over 250 bytes with UTF support), the computation of how
1954    much memory was required could be incorrect, leading to segfaults or other
1955    strange effects.
1957    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1958    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1959    there was a subsequent back reference to those brackets. This meant that, for
1960    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1961    possible to check for precisely this case. All we can do is abandon the
1962    optimization if .* occurs inside capturing brackets when there are any back
1963    references whatsoever. (See below for a better fix that came later.)
1965    26. The handling of the optimization for finding the first character of a
1966    non-anchored pattern, and for finding a character that is required later in the
1967    match were failing in some cases. This didn't break the matching; it just
1968    failed to optimize when it could. The way this is done has been re-implemented.
1970    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1972    28. Added a new feature that provides some of the functionality that Perl
1973    provides with (?{...}). The facility is termed a "callout". The way it is done
1974    in PCRE is for the caller to provide an optional function, by setting
1975    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1976    global variable. By default it is unset, which disables all calling out. To get
1977    the function called, the regex must include (?C) at appropriate points. This
1978    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1979    This provides a means of identifying different callout points. When PCRE
1980    reaches such a point in the regex, if pcre_callout has been set, the external
1981    function is called. It is provided with data in a structure called
1982    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1983    matching continues; if it returns a non-zero value, the match at the current
1984    point fails. However, backtracking will occur if possible. [This was changed
1985    later and other features added - see item 49 below.]
1987    29. pcretest is upgraded to test the callout functionality. It provides a
1988    callout function that displays information. By default, it shows the start of
1989    the match and the current position in the text. There are some new data escapes
1990    to vary what happens:
1992        \C+         in addition, show current contents of captured substrings
1993        \C-         do not supply a callout function
1994        \C!n        return 1 when callout number n is reached
1995        \C!n!m      return 1 when callout number n is reached for the mth time
1997    30. If pcregrep was called with the -l option and just a single file name, it
1998    output "<stdin>" if a match was found, instead of the file name.
2000    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2001    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2002    pcre_exec(). This saves a malloc/free per call. The default value of
2003    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2004    when configuring.
2006    32. The default maximum size of a compiled pattern is 64K. There have been a
2007    few cases of people hitting this limit. The code now uses macros to handle the
2008    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2009    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2010    configuring. Tests 2 and 5 work only with 2-byte links because they output
2011    debugging information about compiled patterns.
2013    33. Internal code re-arrangements:
2015    (a) Moved the debugging function for printing out a compiled regex into
2016        its own source file (printint.c) and used #include to pull it into
2017        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2018        separate copies.
2020    (b) Defined the list of op-code names for debugging as a macro in
2021        internal.h so that it is next to the definition of the opcodes.
2023    (c) Defined a table of op-code lengths for simpler skipping along compiled
2024        code. This is again a macro in internal.h so that it is next to the
2025        definition of the opcodes.
2027    34. Added support for recursive calls to individual subpatterns, along the
2028    lines of Robin Houston's patch (but implemented somewhat differently).
2030    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2031    allow it to read and process whole directories in Win32. This code was
2032    contributed by Lionel Fourquaux; it has not been tested by me.
2034    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2035    used to name a group. Names consist of alphanumerics and underscores, and must
2036    be unique. Back references use the syntax (?P=name) and recursive calls use
2037    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2038    numbers. The function pcre_fullinfo() can be used after compilation to extract
2039    a name/number map. There are three relevant calls:
2041      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2042      PCRE_INFO_NAMECOUNT            yields the number of entries
2043      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2045    The map is a vector of fixed-size entries. The size of each entry depends on
2046    the length of the longest name used. The first two bytes of each entry are the
2047    group number, most significant byte first. There follows the corresponding
2048    name, zero terminated. The names are in alphabetical order.
2050    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2051    case instead of 255. Making it the same both with and without UTF-8 support
2052    means that the same test output works with both.
2054    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2055    calling malloc() with a zero argument.
2057    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2058    optimization. I've improved things by keeping a bitmap of backreferences with
2059    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2060    fact referenced, the optimization can be applied. It is unlikely that a
2061    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2062    the match to follow \n) will appear inside brackets with a number greater than
2063    31, but if it does, any back reference > 31 suppresses the optimization.
2065    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2066    of disabling numbered capturing parentheses. Any opening parenthesis that is
2067    not followed by ? behaves as if it were followed by ?: but named parentheses
2068    can still be used for capturing (and they will acquire numbers in the usual
2069    way).
2071    41. Redesigned the return codes from the match() function into yes/no/error so
2072    that errors can be passed back from deep inside the nested calls. A malloc
2073    failure while inside a recursive subpattern call now causes the
2074    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2076    42. It is now possible to set a limit on the number of times the match()
2077    function is called in a call to pcre_exec(). This facility makes it possible to
2078    limit the amount of recursion and backtracking, though not in a directly
2079    obvious way, because the match() function is used in a number of different
2080    circumstances. The count starts from zero for each position in the subject
2081    string (for non-anchored patterns). The default limit is, for compatibility, a
2082    large number, namely 10 000 000. You can change this in two ways:
2084    (a) When configuring PCRE before making, you can use --with-match-limit=n
2085        to set a default value for the compiled library.
2087    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2088        a different value is set. See 45 below.
2090    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2092    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2093    of things that can be changed at compile time. The first argument specifies
2094    what is wanted and the second points to where the information is to be placed.
2095    The current list of available information is:
2097      PCRE_CONFIG_UTF8
2099    The output is an integer that is set to one if UTF-8 support is available;
2100    otherwise it is set to zero.
2104    The output is an integer that it set to the value of the code that is used for
2105    newline. It is either LF (10) or CR (13).
2109    The output is an integer that contains the number of bytes used for internal
2110    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2114    The output is an integer that contains the threshold above which the POSIX
2115    interface uses malloc() for output vectors. See item 31 above.
2119    The output is an unsigned integer that contains the default limit of the number
2120    of match() calls in a pcre_exec() execution. See 42 above.
2122    44. pcretest has been upgraded by the addition of the -C option. This causes it
2123    to extract all the available output from the new pcre_config() function, and to
2124    output it. The program then exits immediately.
2126    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2127    order to support additional features. One way would have been to define
2128    pcre_exec2() (for example) with extra arguments, but this would not have been
2129    extensible, and would also have required all calls to the original function to
2130    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2131    is used for passing in "extra" data from pcre_study().
2133    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2134    contains the following fields:
2136      flags         a bitmap indicating which of the following fields are set
2137      study_data    opaque data from pcre_study()
2138      match_limit   a way of specifying a limit on match() calls for a specific
2139                      call to pcre_exec()
2140      callout_data  data for callouts (see 49 below)
2142    The flag bits are also defined in pcre.h, and are
2148    The pcre_study() function now returns one of these new pcre_extra blocks, with
2149    the actual study data pointed to by the study_data field, and the
2150    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2151    before. That is, this change is entirely upwards-compatible and requires no
2152    change to existing code.
2154    If you want to pass in additional data to pcre_exec(), you can either place it
2155    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2156    block.
2158    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2159    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2160    times with different match limits, until it finds the minimum value needed for
2161    pcre_exec() to complete. The value is then output. This can be instructive; for
2162    most simple matches the number is quite small, but for pathological cases it
2163    gets very large very quickly.
2165    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2166    returns the size of the data block pointed to by the study_data field in a
2167    pcre_extra block, that is, the value that was passed as the argument to
2168    pcre_malloc() when PCRE was getting memory in which to place the information
2169    created by pcre_study(). The fourth argument should point to a size_t variable.
2170    pcretest has been extended so that this information is shown after a successful
2171    pcre_study() call when information about the compiled regex is being displayed.
2173    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2174    because what follows is always an absolute path. (Later: it turns out that this
2175    is more than cosmetic for MinGW, because it doesn't like empty path
2176    components.)
2178    49. Some changes have been made to the callout feature (see 28 above):
2180    (i)  A callout function now has three choices for what it returns:
2182           0  =>  success, carry on matching
2183         > 0  =>  failure at this point, but backtrack if possible
2184         < 0  =>  serious error, return this value from pcre_exec()
2186         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2187         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2188         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2189         use by callout functions. It will never be used by PCRE itself.
2191    (ii) The pcre_extra structure (see 45 above) has a void * field called
2192         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2193         pcre_callout_block structure has a field of the same name. The contents of
2194         the field passed in the pcre_extra structure are passed to the callout
2195         function in the corresponding field in the callout block. This makes it
2196         easier to use the same callout-containing regex from multiple threads. For
2197         testing, the pcretest program has a new data escape
2199           \C*n        pass the number n (may be negative) as callout_data
2201         If the callout function in pcretest receives a non-zero value as
2202         callout_data, it returns that value.
2204    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2205    there were some redundant $(CFLAGS) in commands that are now specified as
2206    $(LINK), which already includes $(CFLAGS).
2208    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2209    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2210    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2211    one-byte characters throughout. Note that case-insensitive matching applies
2212    only to characters whose values are less than 256. PCRE doesn't support the
2213    notion of cases for higher-valued characters.
2215    (i)   A character class whose characters are all within 0-255 is handled as
2216          a bit map, and the map is inverted for negative classes. Previously, a
2217          character > 255 always failed to match such a class; however it should
2218          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2220    (ii)  A negated character class with a single character < 255 is coded as
2221          "not this character" (OP_NOT). This wasn't working properly when the test
2222          character was multibyte, either singly or repeated.
2224    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2225          mode, for example: \x{100}{2,3}.
2227    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2228          singly or repeated) now correctly test multibyte characters. However,
2229          PCRE doesn't recognize any characters with values greater than 255 as
2230          digits, spaces, or word characters. Such characters always match \D, \S,
2231          and \W, and never match \d, \s, or \w.
2233    (v)   Classes may now contain characters and character ranges with values
2234          greater than 255. For example: [ab\x{100}-\x{400}].
2236    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2237          PCRE in UTF-8 mode.
2239    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2240    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2241    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2242    value.)
2244    53. The single man page has become too large. I have therefore split it up into
2245    a number of separate man pages. These also give rise to individual HTML pages;
2246    these are now put in a separate directory, and there is an index.html page that
2247    lists them all. Some hyperlinking between the pages has been installed.
2249    54. Added convenience functions for handling named capturing parentheses.
2251    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2252    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2253    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2254    are faulted.
2256    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2257    calling configure. These values are used when compiling the dftables.c program
2258    which is run to generate the source of the default character tables. They
2259    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2260    you will need to set these values.
2262    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2265    Version 3.9 02-Jan-02
2266    ---------------------
2268    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2270    2. If --disable-static was given, the building process failed when trying to
2271    build pcretest and pcregrep. (For some reason it was using libtool to compile
2272    them, which is not right, as they aren't part of the library.)
2275    Version 3.8 18-Dec-01
2276    ---------------------
2278    1. The experimental UTF-8 code was completely screwed up. It was packing the
2279    bytes in the wrong order. How dumb can you get?
2282    Version 3.7 29-Oct-01
2283    ---------------------
2285    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2286    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2287    this didn't happen under Solaris 8, where I normally test things.
2289    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2290    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2291    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2292    this fix an hour or so after the initial 3.7 release.)
2295    Version 3.6 23-Oct-01
2296    ---------------------
2298    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2299    offsets passed as NULL with zero offset count.
2301    2. The config.guess and config.sub files had not been updated when I moved to
2302    the latest autoconf.
2305    Version 3.5 15-Aug-01
2306    ---------------------
2308    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2309    had been forgotten.
2311    2. By using declared but undefined structures, we can avoid using "void"
2312    definitions in pcre.h while keeping the internal definitions of the structures
2313    private.
2315    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2316    user point of view, this means that both static and shared libraries are built
2317    by default, but this can be individually controlled. More of the work of
2318    handling this static/shared cases is now inside libtool instead of PCRE's make
2319    file.
2321    4. The pcretest utility is now installed along with pcregrep because it is
2322    useful for users (to test regexs) and by doing this, it automatically gets
2323    relinked by libtool. The documentation has been turned into a man page, so
2324    there are now .1, .txt, and .html versions in /doc.
2326    5. Upgrades to pcregrep:
2327       (i)   Added long-form option names like gnu grep.
2328       (ii)  Added --help to list all options with an explanatory phrase.
2329       (iii) Added -r, --recursive to recurse into sub-directories.
2330       (iv)  Added -f, --file to read patterns from a file.
2332    6. pcre_exec() was referring to its "code" argument before testing that
2333    argument for NULL (and giving an error if it was NULL).
2335    7. Upgraded Makefile.in to allow for compiling in a different directory from
2336    the source directory.
2338    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2339    options bits, the pointer it was passed was to an int instead of to an unsigned
2340    long int. This mattered only on 64-bit systems.
2342    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2343    generated) instead of pcre.in, which it its source. Also made the same change
2344    in several of the .c files.
2346    10. A new release of gcc defines printf() as a macro, which broke pcretest
2347    because it had an ifdef in the middle of a string argument for printf(). Fixed
2348    by using separate calls to printf().
2350    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2351    script, to force use of CR or LF instead of \n in the source. On non-Unix
2352    systems, the value can be set in config.h.
2354    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2355    absolute limit. Changed the text of the error message to make this clear, and
2356    likewise updated the man page.
2358    13. The limit of 99 on the number of capturing subpatterns has been removed.
2359    The new limit is 65535, which I hope will not be a "real" limit.
2362  Version 3.4 22-Aug-00  Version 3.4 22-Aug-00
2363  ---------------------  ---------------------

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