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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.4 10-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).
38    8.  Changed all #include <config.h> to #include "config.h". There were also
39        some further <pcre.h> cases that I changed to "pcre.h".
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
44    10. It was pointed out to me that arrays of string pointers cause lots of
45        relocations when a shared library is dynamically loaded. A technique of
46        using a single long string with a table of offsets can drastically reduce
47        these. I have refactored PCRE in four places to do this. The result is
48        dramatic:
50          Originally:                          290
51          After changing UCP table:            187
52          After changing error message table:   43
53          After changing table of "verbs"       36
54          After changing table of Posix names   22
56        Thanks to the folks working on Gregex for glib for this insight.
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
61    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
63    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
64        checked only for CRLF.
66    14. Added casts to pcretest.c to avoid compiler warnings.
68    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
71    Version 7.3 28-Aug-07
72    ---------------------
74     1. In the rejigging of the build system that eventually resulted in 7.1, the
75        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
76        brackets there is not right, since it causes compilers to look for an
77        installed pcre.h, not the version that is in the source that is being
78        compiled (which of course may be different). I have changed it back to:
80          #include "pcre.h"
82        I have a vague recollection that the change was concerned with compiling in
83        different directories, but in the new build system, that is taken care of
84        by the VPATH setting the Makefile.
86     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
87        when the subject happened to end in the byte 0x85 (e.g. if the last
88        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
89        characters but of course it shouldn't be taken as a newline when it is part
90        of another character. The bug was that, for an unlimited repeat of . in
91        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
92        characters when looking for a newline.
94     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
96     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
97        in debug output.
99     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
100        long printing in the pcrecpp unittest when running under MinGW.
102     6. ESC_K was left out of the EBCDIC table.
104     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
105        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
106        limit also applies to "virtual nesting" when a pattern is recursive, and in
107        this case 1000 isn't so big. I have been able to remove this limit at the
108        expense of backing off one optimization in certain circumstances. Normally,
109        when pcre_exec() would call its internal match() function recursively and
110        immediately return the result unconditionally, it uses a "tail recursion"
111        feature to save stack. However, when a subpattern that can match an empty
112        string has an unlimited repetition quantifier, it no longer makes this
113        optimization. That gives it a stack frame in which to save the data for
114        checking that an empty string has been matched. Previously this was taken
115        from the 1000-entry workspace that had been reserved. So now there is no
116        explicit limit, but more stack is used.
118     8. Applied Daniel's patches to solve problems with the import/export magic
119        syntax that is required for Windows, and which was going wrong for the
120        pcreposix and pcrecpp parts of the library. These were overlooked when this
121        problem was solved for the main library.
123     9. There were some crude static tests to avoid integer overflow when computing
124        the size of patterns that contain repeated groups with explicit upper
125        limits. As the maximum quantifier is 65535, the maximum group length was
126        set at 30,000 so that the product of these two numbers did not overflow a
127        32-bit integer. However, it turns out that people want to use groups that
128        are longer than 30,000 bytes (though not repeat them that many times).
129        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
130        made it possible to implement the integer overflow checks in a much more
131        dynamic way, which I have now done. The artificial limitation on group
132        length has been removed - we now have only the limit on the total length of
133        the compiled pattern, which depends on the LINK_SIZE setting.
135    10. Fixed a bug in the documentation for get/copy named substring when
136        duplicate names are permitted. If none of the named substrings are set, the
137        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
138        empty string.
140    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
141        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
142        because the ] is interpreted as the first data character and the
143        terminating ] is not found. PCRE has been made compatible with Perl in this
144        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
145        cause memory overwriting.
147    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
148        string has been matched (to stop an infinite loop). It was not recognizing
149        a conditional subpattern that could match an empty string if that
150        subpattern was within another subpattern. For example, it looped when
151        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
152        condition was not nested. This bug has been fixed.
154    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
155        past the start of the subject in the presence of bytes with the top bit
156        set, for example "\x8aBCD".
158    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
159        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
161    14. Optimized (?!) to (*FAIL).
163    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
164        This restricts code points to be within the range 0 to 0x10FFFF, excluding
165        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
166        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
167        does: it's just the validity check that is more restrictive.
169    16. Inserted checks for integer overflows during escape sequence (backslash)
170        processing, and also fixed erroneous offset values for syntax errors during
171        backslash processing.
173    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
174        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
176    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
177        caused an overrun.
179    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
180        something other than just ASCII characters) inside a group that had an
181        unlimited repeat caused a loop at compile time (while checking to see
182        whether the group could match an empty string).
184    20. Debugging a pattern containing \p or \P could cause a crash. For example,
185        [\P{Any}] did so. (Error in the code for printing property names.)
187    21. An orphan \E inside a character class could cause a crash.
189    22. A repeated capturing bracket such as (A)? could cause a wild memory
190        reference during compilation.
192    23. There are several functions in pcre_compile() that scan along a compiled
193        expression for various reasons (e.g. to see if it's fixed length for look
194        behind). There were bugs in these functions when a repeated \p or \P was
195        present in the pattern. These operators have additional parameters compared
196        with \d, etc, and these were not being taken into account when moving along
197        the compiled data. Specifically:
199        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
200            length.
202        (b) An item such as \pL+ within a repeated group could cause crashes or
203            loops.
205        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
206            "reference to non-existent subpattern" error.
208        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
210    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
211        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
213    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
215    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
216        character were causing crashes (broken optimization).
218    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
219        \p or \P) caused a compile-time loop.
221    28. More problems have arisen in unanchored patterns when CRLF is a valid line
222        break. For example, the unstudied pattern [\r\n]A does not match the string
223        "\r\nA" because change 7.0/46 below moves the current point on by two
224        characters after failing to match at the start. However, the pattern \nA
225        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
226        the same is true. There doesn't seem any very clean way out of this, but
227        what I have chosen to do makes the common cases work: PCRE now takes note
228        of whether there can be an explicit match for \r or \n anywhere in the
229        pattern, and if so, 7.0/46 no longer applies. As part of this change,
230        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
231        pattern has explicit CR or LF references.
233    29. Added (*CR) etc for changing newline setting at start of pattern.
236    Version 7.2 19-Jun-07
237    ---------------------
239     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
240        which is apparently normally available under Windows.
242     2. Re-jig the pcregrep tests with different newline settings in an attempt
243        to make them independent of the local environment's newline setting.
245     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
247     4. Some of the "internals" tests were previously cut out when the link size
248        was not 2, because the output contained actual offsets. The recent new
249        "Z" feature of pcretest means that these can be cut out, making the tests
250        usable with all link sizes.
252     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
253        stack recursion. This gives a massive performance boost under BSD, but just
254        a small improvement under Linux. However, it saves one field in the frame
255        in all cases.
257     6. Added more features from the forthcoming Perl 5.10:
259        (a) (?-n) (where n is a string of digits) is a relative subroutine or
260            recursion call. It refers to the nth most recently opened parentheses.
262        (b) (?+n) is also a relative subroutine call; it refers to the nth next
263            to be opened parentheses.
265        (c) Conditions that refer to capturing parentheses can be specified
266            relatively, for example, (?(-2)... or (?(+3)...
268        (d) \K resets the start of the current match so that everything before
269            is not part of it.
271        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
273        (f) \g{name} is another synonym - part of Perl 5.10's unification of
274            reference syntax.
276        (g) (?| introduces a group in which the numbering of parentheses in each
277            alternative starts with the same number.
279        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
281     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
284     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
285        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
286        for detecting groups that can match an empty string.
288     9. A pattern with a very large number of alternatives (more than several
289        hundred) was running out of internal workspace during the pre-compile
290        phase, where pcre_compile() figures out how much memory will be needed. A
291        bit of new cunning has reduced the workspace needed for groups with
292        alternatives. The 1000-alternative test pattern now uses 12 bytes of
293        workspace instead of running out of the 4096 that are available.
295    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
297    11. Applied patch from Google to remove an optimization that didn't quite work.
298        The report of the bug said:
300          pcrecpp::RE("a*").FullMatch("aaa") matches, while
301          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
302          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
304    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
305        it matched the wrong number of bytes.
308    Version 7.1 24-Apr-07
309    ---------------------
311     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
312        that is more "standard", making use of automake and other Autotools. There
313        is some re-arrangement of the files and adjustment of comments consequent
314        on this.
316     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
317        for recursive directory scanning broke on some systems because the files
318        are not scanned in any specific order and on different systems the order
319        was different. A call to "sort" has been inserted into RunGrepTest for the
320        approprate test as a short-term fix. In the longer term there may be an
321        alternative.
323     3. I had an email from Eric Raymond about problems translating some of PCRE's
324        man pages to HTML (despite the fact that I distribute HTML pages, some
325        people do their own conversions for various reasons). The problems
326        concerned the use of low-level troff macros .br and .in. I have therefore
327        removed all such uses from the man pages (some were redundant, some could
328        be replaced by .nf/.fi pairs). The 132html script that I use to generate
329        HTML has been updated to handle .nf/.fi and to complain if it encounters
330        .br or .in.
332     4. Updated comments in configure.ac that get placed in config.h.in and also
333        arranged for config.h to be included in the distribution, with the name
334        config.h.generic, for the benefit of those who have to compile without
335        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
337     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
338        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
339        makevp.bat for the current PCRE, using the additional files
340        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
342     6. A Windows user reported a minor discrepancy with test 2, which turned out
343        to be caused by a trailing space on an input line that had got lost in his
344        copy. The trailing space was an accident, so I've just removed it.
346     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
347        that is needed.
349     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
350        as "const" (a) because they are and (b) because it helps the PHP
351        maintainers who have recently made a script to detect big data structures
352        in the php code that should be moved to the .rodata section. I remembered
353        to update Builducptable as well, so it won't revert if ucptable.h is ever
354        re-created.
356     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
357        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
358        order to be able to cut out the UTF-8 tables in the latter when UTF-8
359        support is not required. This saves 1.5-2K of code, which is important in
360        some applications.
362        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
363        so as not to refer to the tables, even though these functions will never be
364        called when UTF-8 support is disabled. Otherwise there are problems with a
365        shared library.
367    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
369        (a) It was defining its arguments as char * instead of void *.
371        (b) It was assuming that all moves were upwards in memory; this was true
372            a long time ago when I wrote it, but is no longer the case.
374        The emulated memove() is provided for those environments that have neither
375        memmove() nor bcopy(). I didn't think anyone used it these days, but that
376        is clearly not the case, as these two bugs were recently reported.
378    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
379        and Detrail to create the HTML documentation, the .txt form of the man
380        pages, and it removes trailing spaces from listed files. It also creates
381        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
382        case, it wraps all the #defines with #ifndefs. This script should be run
383        before "make dist".
385    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
386        with Unicode property support.
388        (a) For a maximizing quantifier, if the two different cases of the
389            character were of different lengths in their UTF-8 codings (there are
390            some cases like this - I found 11), and the matching function had to
391            back up over a mixture of the two cases, it incorrectly assumed they
392            were both the same length.
394        (b) When PCRE was configured to use the heap rather than the stack for
395            recursion during matching, it was not correctly preserving the data for
396            the other case of a UTF-8 character when checking ahead for a match
397            while processing a minimizing repeat. If the check also involved
398            matching a wide character, but failed, corruption could cause an
399            erroneous result when trying to check for a repeat of the original
400            character.
402    13. Some tidying changes to the testing mechanism:
404        (a) The RunTest script now detects the internal link size and whether there
405            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
406            values substituted by "configure". (The RunGrepTest script already did
407            this for UTF-8.) The configure.ac script no longer substitutes the
408            relevant variables.
410        (b) The debugging options /B and /D in pcretest show the compiled bytecode
411            with length and offset values. This means that the output is different
412            for different internal link sizes. Test 2 is skipped for link sizes
413            other than 2 because of this, bypassing the problem. Unfortunately,
414            there was also a test in test 3 (the locale tests) that used /B and
415            failed for link sizes other than 2. Rather than cut the whole test out,
416            I have added a new /Z option to pcretest that replaces the length and
417            offset values with spaces. This is now used to make test 3 independent
418            of link size. (Test 2 will be tidied up later.)
420    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
421        segmentation fault instead of returning the appropriate error message.
423    15. In multiline mode when the newline sequence was set to "any", the pattern
424        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
425        This doesn't seem right; it now treats the CRLF combination as the line
426        ending, and so does not match in that case. It's only a pattern such as ^$
427        that would hit this one: something like ^ABC$ would have failed after \r
428        and then tried again after \r\n.
430    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
431        in an attempt to make files that differ only in their line terminators
432        compare equal. This works on Linux.
434    17. Under certain error circumstances pcregrep might try to free random memory
435        as it exited. This is now fixed, thanks to valgrind.
437    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
438        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
439        was because its rules for how to advance for /g after matching an empty
440        string at the end of a line did not allow for this case. They now check for
441        it specially.
443    20. pcretest is supposed to handle patterns and data of any length, by
444        extending its buffers when necessary. It was getting this wrong when the
445        buffer for a data line had to be extended.
447    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
448        CRLF as a newline sequence.
450    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
451        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
452        I have nevertheless tidied it up.
454    23. Added some casts to kill warnings from HP-UX ia64 compiler.
456    24. Added a man page for pcre-config.
459    Version 7.0 19-Dec-06
460    ---------------------
462     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
463        moving to gcc 4.1.1.
465     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
466        sys/time.h, which is documented as needed for this function. It doesn't
467        seem to matter on Linux, but it showed up on some releases of OS X.
469     3. It seems that there are systems where bytes whose values are greater than
470        127 match isprint() in the "C" locale. The "C" locale should be the
471        default when a C program starts up. In most systems, only ASCII printing
472        characters match isprint(). This difference caused the output from pcretest
473        to vary, making some of the tests fail. I have changed pcretest so that:
475        (a) When it is outputting text in the compiled version of a pattern, bytes
476            other than 32-126 are always shown as hex escapes.
478        (b) When it is outputting text that is a matched part of a subject string,
479            it does the same, unless a different locale has been set for the match
480            (using the /L modifier). In this case, it uses isprint() to decide.
482     4. Fixed a major bug that caused incorrect computation of the amount of memory
483        required for a compiled pattern when options that changed within the
484        pattern affected the logic of the preliminary scan that determines the
485        length. The relevant options are -x, and -i in UTF-8 mode. The result was
486        that the computed length was too small. The symptoms of this bug were
487        either the PCRE error "internal error: code overflow" from pcre_compile(),
488        or a glibc crash with a message such as "pcretest: free(): invalid next
489        size (fast)". Examples of patterns that provoked this bug (shown in
490        pcretest format) are:
492          /(?-x: )/x
493          /(?x)(?-x: \s*#\s*)/
494          /((?i)[\x{c0}])/8
495          /(?i:[\x{c0}])/8
497        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
498        is now done differently.
500     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
501        wrapper classes; (b) implement a new function in the C++ scanner that is
502        more efficient than the old way of doing things because it avoids levels of
503        recursion in the regex matching; (c) add a paragraph to the documentation
504        for the FullMatch() function.
506     6. The escape sequence \n was being treated as whatever was defined as
507        "newline". Not only was this contrary to the documentation, which states
508        that \n is character 10 (hex 0A), but it also went horribly wrong when
509        "newline" was defined as CRLF. This has been fixed.
511     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
512        was being set to -1 for the "end of line" case (supposedly a value that no
513        character can have). Though this value is never used (the check for end of
514        line is "zero bytes in current character"), it caused compiler complaints.
515        I've changed it to 0xffffffff.
517     8. In pcre_version.c, the version string was being built by a sequence of
518        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
519        string (as it is for production releases) called a macro with an empty
520        argument. The C standard says the result of this is undefined. The gcc
521        compiler treats it as an empty string (which was what was wanted) but it is
522        reported that Visual C gives an error. The source has been hacked around to
523        avoid this problem.
525     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
526        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
527        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
528        of them did).
530    10. Originally, pcretest opened its input and output without "b"; then I was
531        told that "b" was needed in some environments, so it was added for release
532        5.0 to both the input and output. (It makes no difference on Unix-like
533        systems.) Later I was told that it is wrong for the input on Windows. I've
534        now abstracted the modes into two macros, to make it easier to fiddle with
535        them, and removed "b" from the input mode under Windows.
537    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
539    12. Added -help and --help to pcretest as an official way of being reminded
540        of the options.
542    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
543        and pcrecpp.cc because they annoy compilers at high warning levels.
545    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
547    15. Fixed an occurrence of == in configure.ac that should have been = (shell
548        scripts are not C programs :-) and which was not noticed because it works
549        on Linux.
551    16. pcretest is supposed to handle any length of pattern and data line (as one
552        line or as a continued sequence of lines) by extending its input buffer if
553        necessary. This feature was broken for very long pattern lines, leading to
554        a string of junk being passed to pcre_compile() if the pattern was longer
555        than about 50K.
557    17. I have done a major re-factoring of the way pcre_compile() computes the
558        amount of memory needed for a compiled pattern. Previously, there was code
559        that made a preliminary scan of the pattern in order to do this. That was
560        OK when PCRE was new, but as the facilities have expanded, it has become
561        harder and harder to keep it in step with the real compile phase, and there
562        have been a number of bugs (see for example, 4 above). I have now found a
563        cunning way of running the real compile function in a "fake" mode that
564        enables it to compute how much memory it would need, while actually only
565        ever using a few hundred bytes of working memory and without too many
566        tests of the mode. This should make future maintenance and development
567        easier. A side effect of this work is that the limit of 200 on the nesting
568        depth of parentheses has been removed (though this was never a serious
569        limitation, I suspect). However, there is a downside: pcre_compile() now
570        runs more slowly than before (30% or more, depending on the pattern). I
571        hope this isn't a big issue. There is no effect on runtime performance.
573    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
574        newline (only possible for the last line of a file) and it was a
575        pattern that set a locale (followed by /Lsomething), pcretest crashed.
577    19. Added additional timing features to pcretest. (1) The -tm option now times
578        matching only, not compiling. (2) Both -t and -tm can be followed, as a
579        separate command line item, by a number that specifies the number of
580        repeats to use when timing. The default is 50000; this gives better
581        precision, but takes uncomfortably long for very large patterns.
583    20. Extended pcre_study() to be more clever in cases where a branch of a
584        subpattern has no definite first character. For example, (a*|b*)[cd] would
585        previously give no result from pcre_study(). Now it recognizes that the
586        first character must be a, b, c, or d.
588    21. There was an incorrect error "recursive call could loop indefinitely" if
589        a subpattern (or the entire pattern) that was being tested for matching an
590        empty string contained only one non-empty item after a nested subpattern.
591        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
592        incorrectly, because the \d was being skipped in the check.
594    22. The pcretest program now has a new pattern option /B and a command line
595        option -b, which is equivalent to adding /B to every pattern. This causes
596        it to show the compiled bytecode, without the additional information that
597        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
598        is the same as /B/I).
600    23. A new optimization is now able automatically to treat some sequences such
601        as a*b as a*+b. More specifically, if something simple (such as a character
602        or a simple class like \d) has an unlimited quantifier, and is followed by
603        something that cannot possibly match the quantified thing, the quantifier
604        is automatically "possessified".
606    24. A recursive reference to a subpattern whose number was greater than 39
607        went wrong under certain circumstances in UTF-8 mode. This bug could also
608        have affected the operation of pcre_study().
610    25. Realized that a little bit of performance could be had by replacing
611        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
613    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
615    27. Possessive quantifiers such as a++ were previously implemented by turning
616        them into atomic groups such as ($>a+). Now they have their own opcodes,
617        which improves performance. This includes the automatically created ones
618        from 23 above.
620    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
621        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
622        the first matched character to be a colon. This applied both to named and
623        numbered groups.
625    29. The ucpinternal.h header file was missing its idempotency #ifdef.
627    30. I was sent a "project" file called libpcre.a.dev which I understand makes
628        building PCRE on Windows easier, so I have included it in the distribution.
630    31. There is now a check in pcretest against a ridiculously large number being
631        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
632        loop, the loop is abandoned.
634    32. Forward references to subpatterns in conditions such as (?(2)...) where
635        subpattern 2 is defined later cause pcre_compile() to search forwards in
636        the pattern for the relevant set of parentheses. This search went wrong
637        when there were unescaped parentheses in a character class, parentheses
638        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
640    33. "Subroutine" calls and backreferences were previously restricted to
641        referencing subpatterns earlier in the regex. This restriction has now
642        been removed.
644    34. Added a number of extra features that are going to be in Perl 5.10. On the
645        whole, these are just syntactic alternatives for features that PCRE had
646        previously implemented using the Python syntax or my own invention. The
647        other formats are all retained for compatibility.
649        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
650            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
651            also .NET compatible.
653        (b) A recursion or subroutine call to a named group can now be defined as
654            (?&name) as well as (?P>name).
656        (c) A backreference to a named group can now be defined as \k<name> or
657            \k'name' as well as (?P=name). The new forms, as well as being in Perl
658            5.10, are also .NET compatible.
660        (d) A conditional reference to a named group can now use the syntax
661            (?(<name>) or (?('name') as well as (?(name).
663        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
664            groups (named and numbered) that are never evaluated inline, but can be
665            called as "subroutines" from elsewhere. In effect, the DEFINE condition
666            is always false. There may be only one alternative in such a group.
668        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
669            as the simple (?(R). The condition is true only if the most recent
670            recursion is that of the given number or name. It does not search out
671            through the entire recursion stack.
673        (g) The escape \gN or \g{N} has been added, where N is a positive or
674            negative number, specifying an absolute or relative reference.
676    35. Tidied to get rid of some further signed/unsigned compiler warnings and
677        some "unreachable code" warnings.
679    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
680        things, this adds five new scripts.
682    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
683        There were also incompatibilities regarding the handling of \Q..\E inside
684        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
685        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
687    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
688        matches an empty string, and forcibly breaks the loop. There were bugs in
689        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
690        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
691        separate and independent bugs (that affected different cases) have been
692        fixed.
694    39. Refactored the code to abolish the use of different opcodes for small
695        capturing bracket numbers. This is a tidy that I avoided doing when I
696        removed the limit on the number of capturing brackets for 3.5 back in 2001.
697        The new approach is not only tidier, it makes it possible to reduce the
698        memory needed to fix the previous bug (38).
700    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
701        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
702        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
703        mode.
705    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
706        report.
708    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
709        copy construction and assignment in the C++ wrapper.
711    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
712        couple of bugs that could have given wrong results in the "--newline=crlf"
713        case.
715    44. Added a number of casts and did some reorganization of signed/unsigned int
716        variables following suggestions from Dair Grant. Also renamed the variable
717        "this" as "item" because it is a C++ keyword.
719    45. Arranged for dftables to add
721          #include "pcre_internal.h"
723        to pcre_chartables.c because without it, gcc 4.x may remove the array
724        definition from the final binary if PCRE is built into a static library and
725        dead code stripping is activated.
727    46. For an unanchored pattern, if a match attempt fails at the start of a
728        newline sequence, and the newline setting is CRLF or ANY, and the next two
729        characters are CRLF, advance by two characters instead of one.
732    Version 6.7 04-Jul-06
733    ---------------------
735     1. In order to handle tests when input lines are enormously long, pcretest has
736        been re-factored so that it automatically extends its buffers when
737        necessary. The code is crude, but this _is_ just a test program. The
738        default size has been increased from 32K to 50K.
740     2. The code in pcre_study() was using the value of the re argument before
741        testing it for NULL. (Of course, in any sensible call of the function, it
742        won't be NULL.)
744     3. The memmove() emulation function in pcre_internal.h, which is used on
745        systems that lack both memmove() and bcopy() - that is, hardly ever -
746        was missing a "static" storage class specifier.
748     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
749        containing an extended class (one that cannot be represented by a bitmap
750        because it contains high-valued characters or Unicode property items, e.g.
751        [\pZ]). Almost always one would set UTF-8 mode when processing such a
752        pattern, but PCRE should not loop if you do not (it no longer does).
753        [Detail: two cases were found: (a) a repeated subpattern containing an
754        extended class; (b) a recursive reference to a subpattern that followed a
755        previous extended class. It wasn't skipping over the extended class
756        correctly when UTF-8 mode was not set.]
758     5. A negated single-character class was not being recognized as fixed-length
759        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
760        compile error "lookbehind assertion is not fixed length".
762     6. The RunPerlTest auxiliary script was showing an unexpected difference
763        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
764        write a Perl script that can interpret lines of an input file either as
765        byte characters or as UTF-8, which is what "perltest" was being required to
766        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
767        can't do is switch easily at run time between having the "use utf8;" pragma
768        or not. In the end, I fudged it by using the RunPerlTest script to insert
769        "use utf8;" explicitly for the UTF-8 tests.
771     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
772        the end of the subject string, contrary to the documentation and to what
773        Perl does. This was true of both matching functions. Now it matches only at
774        the start of the subject and immediately after *internal* newlines.
776     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
777        a pointer to an int instead of a pointer to an unsigned long int. This
778        caused problems on 64-bit systems.
780     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
781        instance of the 'standard' template library not being so standard".
783    10. There was no check on the number of named subpatterns nor the maximum
784        length of a subpattern name. The product of these values is used to compute
785        the size of the memory block for a compiled pattern. By supplying a very
786        long subpattern name and a large number of named subpatterns, the size
787        computation could be caused to overflow. This is now prevented by limiting
788        the length of names to 32 characters, and the number of named subpatterns
789        to 10,000.
791    11. Subpatterns that are repeated with specific counts have to be replicated in
792        the compiled pattern. The size of memory for this was computed from the
793        length of the subpattern and the repeat count. The latter is limited to
794        65535, but there was no limit on the former, meaning that integer overflow
795        could in principle occur. The compiled length of a repeated subpattern is
796        now limited to 30,000 bytes in order to prevent this.
798    12. Added the optional facility to have named substrings with the same name.
800    13. Added the ability to use a named substring as a condition, using the
801        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
802        are numbers (not recommended). Forward references are permitted.
804    14. Added forward references in named backreferences (if you see what I mean).
806    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
807        pattern could run off the end of the subject. For example, the pattern
808        "(?s)(.{1,5})"8 did this with the subject "ab".
810    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
811        PCRE_CASELESS was set when matching characters that were quantified with ?
812        or *.
814    17. A character class other than a single negated character that had a minimum
815        but no maximum quantifier - for example [ab]{6,} - was not handled
816        correctly by pce_dfa_exec(). It would match only one character.
818    18. A valid (though odd) pattern that looked like a POSIX character
819        class but used an invalid character after [ (for example [[,abc,]]) caused
820        pcre_compile() to give the error "Failed: internal error: code overflow" or
821        in some cases to crash with a glibc free() error. This could even happen if
822        the pattern terminated after [[ but there just happened to be a sequence of
823        letters, a binary zero, and a closing ] in the memory that followed.
825    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
826        over the years. Originally (before any Unicode support), just the bottom 8
827        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
828        output from "man perlunicode" includes this:
830          The regular expression compiler produces polymorphic opcodes.  That
831          is, the pattern adapts to the data and automatically switches to
832          the Unicode character scheme when presented with Unicode data--or
833          instead uses a traditional byte scheme when presented with byte
834          data.
836        Sadly, a wide octal escape does not cause a switch, and in a string with
837        no other multibyte characters, these octal escapes are treated as before.
838        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
839        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
840        Unicode string.
842        I have not perpetrated such confusion in PCRE. Up till now, it took just
843        the bottom 8 bits, as in old Perl. I have now made octal escapes with
844        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
845        translate to the appropriate multibyte character.
847    29. Applied some refactoring to reduce the number of warnings from Microsoft
848        and Borland compilers. This has included removing the fudge introduced
849        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
850        a warning about an unused variable.
852    21. PCRE has not included VT (character 0x0b) in the set of whitespace
853        characters since release 4.0, because Perl (from release 5.004) does not.
854        [Or at least, is documented not to: some releases seem to be in conflict
855        with the documentation.] However, when a pattern was studied with
856        pcre_study() and all its branches started with \s, PCRE still included VT
857        as a possible starting character. Of course, this did no harm; it just
858        caused an unnecessary match attempt.
860    22. Removed a now-redundant internal flag bit that recorded the fact that case
861        dependency changed within the pattern. This was once needed for "required
862        byte" processing, but is no longer used. This recovers a now-scarce options
863        bit. Also moved the least significant internal flag bit to the most-
864        significant bit of the word, which was not previously used (hangover from
865        the days when it was an int rather than a uint) to free up another bit for
866        the future.
868    23. Added support for CRLF line endings as well as CR and LF. As well as the
869        default being selectable at build time, it can now be changed at runtime
870        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
871        specify that it is scanning data with non-default line endings.
873    24. Changed the definition of CXXLINK to make it agree with the definition of
874        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
876    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
877        recursions. This makes a big different to stack usage for some patterns.
879    26. If a subpattern containing a named recursion or subroutine reference such
880        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
881        the space required for the compiled pattern went wrong and gave too small a
882        value. Depending on the environment, this could lead to "Failed: internal
883        error: code overflow at offset 49" or "glibc detected double free or
884        corruption" errors.
886    27. Applied patches from Google (a) to support the new newline modes and (b) to
887        advance over multibyte UTF-8 characters in GlobalReplace.
889    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
890        difference for some implementation of PCRE in some Windows version.
892    29. Added some extra testing facilities to pcretest:
894        \q<number>   in a data line sets the "match limit" value
895        \Q<number>   in a data line sets the "match recursion limt" value
896        -S <number>  sets the stack size, where <number> is in megabytes
898        The -S option isn't available for Windows.
901    Version 6.6 06-Feb-06
902    ---------------------
904     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
905        in pcreposix.h. I have copied the definition from pcre.h.
907     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
908        because pcre.h is no longer a built file.
910     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
911        not normally included in the compiled code.
914    Version 6.5 01-Feb-06
915    ---------------------
917     1. When using the partial match feature with pcre_dfa_exec(), it was not
918        anchoring the second and subsequent partial matches at the new starting
919        point. This could lead to incorrect results. For example, with the pattern
920        /1234/, partially matching against "123" and then "a4" gave a match.
922     2. Changes to pcregrep:
924        (a) All non-match returns from pcre_exec() were being treated as failures
925            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
926            error message is output. Some extra information is given for the
927            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
928            probably the only errors that are likely to be caused by users (by
929            specifying a regex that has nested indefinite repeats, for instance).
930            If there are more than 20 of these errors, pcregrep is abandoned.
932        (b) A binary zero was treated as data while matching, but terminated the
933            output line if it was written out. This has been fixed: binary zeroes
934            are now no different to any other data bytes.
936        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
937            used to set a locale for matching. The --locale=xxxx long option has
938            been added (no short equivalent) to specify a locale explicitly on the
939            pcregrep command, overriding the environment variables.
941        (d) When -B was used with -n, some line numbers in the output were one less
942            than they should have been.
944        (e) Added the -o (--only-matching) option.
946        (f) If -A or -C was used with -c (count only), some lines of context were
947            accidentally printed for the final match.
949        (g) Added the -H (--with-filename) option.
951        (h) The combination of options -rh failed to suppress file names for files
952            that were found from directory arguments.
954        (i) Added the -D (--devices) and -d (--directories) options.
956        (j) Added the -F (--fixed-strings) option.
958        (k) Allow "-" to be used as a file name for -f as well as for a data file.
960        (l) Added the --colo(u)r option.
962        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
963            is not present by default.
965     3. A nasty bug was discovered in the handling of recursive patterns, that is,
966        items such as (?R) or (?1), when the recursion could match a number of
967        alternatives. If it matched one of the alternatives, but subsequently,
968        outside the recursion, there was a failure, the code tried to back up into
969        the recursion. However, because of the way PCRE is implemented, this is not
970        possible, and the result was an incorrect result from the match.
972        In order to prevent this happening, the specification of recursion has
973        been changed so that all such subpatterns are automatically treated as
974        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
976     4. I had overlooked the fact that, in some locales, there are characters for
977        which isalpha() is true but neither isupper() nor islower() are true. In
978        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
979        and ordfeminine) are like this. This affected the treatment of \w and \W
980        when they appeared in character classes, but not when they appeared outside
981        a character class. The bit map for "word" characters is now created
982        separately from the results of isalnum() instead of just taking it from the
983        upper, lower, and digit maps. (Plus the underscore character, of course.)
985     5. The above bug also affected the handling of POSIX character classes such as
986        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
987        permanent tables. Instead, the bit maps for such a class were previously
988        created as the appropriate unions of the upper, lower, and digit bitmaps.
989        Now they are created by subtraction from the [[:word:]] class, which has
990        its own bitmap.
992     6. The [[:blank:]] character class matches horizontal, but not vertical space.
993        It is created by subtracting the vertical space characters (\x09, \x0a,
994        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
995        subtraction was done in the overall bitmap for a character class, meaning
996        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
997        be recognized. This bug has been fixed.
999     7. Patches from the folks at Google:
1001          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1002          real life, but is still worth protecting against".
1004          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1005          regular expressions".
1007          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1008          have it.
1010          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1011          "configure" and the latter not, in order to fix a problem somebody had
1012          with compiling the Arg class on HP-UX.
1014          (e) Improve the error-handling of the C++ wrapper a little bit.
1016          (f) New tests for checking recursion limiting.
1018     8. The pcre_memmove() function, which is used only if the environment does not
1019        have a standard memmove() function (and is therefore rarely compiled),
1020        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1021        returning a result (though PCRE never actually uses the result).
1023     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1024        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1025        returned instead of calling malloc() with an overflowing number that would
1026        most likely cause subsequent chaos.
1028    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1030    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1031        with this option is matched, the nmatch and pmatch options of regexec() are
1032        ignored.
1034    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1035        provided in case anyone wants to the the POSIX interface with UTF-8
1036        strings.
1038    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1039        C++ linking (needed for some HP-UX environments).
1041    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1042        (unused parameter) and in the pcre_printint() function (omitted "default"
1043        switch label when the default is to do nothing).
1045    15. Added some code to make it possible, when PCRE is compiled as a C++
1046        library, to replace subject pointers for pcre_exec() with a smart pointer
1047        class, thus making it possible to process discontinuous strings.
1049    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1050        much the same function. They were added by different people who were trying
1051        to make PCRE easy to compile on non-Unix systems. It has been suggested
1052        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1053        for compiling on Windows systems. I have therefore replaced it with
1054        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1055        defaults to "extern" for C or "extern C" for C++, which works fine on
1056        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1057        SCOPE with something explicit in config.h. In addition:
1059        (a) pcreposix.h still had just "extern" instead of either of these macros;
1060            I have replaced it with PCRE_DATA_SCOPE.
1062        (b) Functions such as _pcre_xclass(), which are internal to the library,
1063            but external in the C sense, all had PCRE_EXPORT in their definitions.
1064            This is apparently wrong for the Windows case, so I have removed it.
1065            (It makes no difference on Unix-like systems.)
1067    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1068        of recursive calls to match(). This is different to MATCH_LIMIT because
1069        that limits the total number of calls to match(), not all of which increase
1070        the depth of recursion. Limiting the recursion depth limits the amount of
1071        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1072        when PCRE is compiled, and changed at run time. A patch from Google adds
1073        this functionality to the C++ interface.
1075    18. Changes to the handling of Unicode character properties:
1077        (a) Updated the table to Unicode 4.1.0.
1079        (b) Recognize characters that are not in the table as "Cn" (undefined).
1081        (c) I revised the way the table is implemented to a much improved format
1082            which includes recognition of ranges. It now supports the ranges that
1083            are defined in UnicodeData.txt, and it also amalgamates other
1084            characters into ranges. This has reduced the number of entries in the
1085            table from around 16,000 to around 3,000, thus reducing its size
1086            considerably. I realized I did not need to use a tree structure after
1087            all - a binary chop search is just as efficient. Having reduced the
1088            number of entries, I extended their size from 6 bytes to 8 bytes to
1089            allow for more data.
1091        (d) Added support for Unicode script names via properties such as \p{Han}.
1093    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1094        matching that character.
1096    20. When matching a repeated Unicode property with a minimum greater than zero,
1097        (for example \pL{2,}), PCRE could look past the end of the subject if it
1098        reached it while seeking the minimum number of characters. This could
1099        happen only if some of the characters were more than one byte long, because
1100        there is a check for at least the minimum number of bytes.
1102    21. Refactored the implementation of \p and \P so as to be more general, to
1103        allow for more different types of property in future. This has changed the
1104        compiled form incompatibly. Anybody with saved compiled patterns that use
1105        \p or \P will have to recompile them.
1107    22. Added "Any" and "L&" to the supported property types.
1109    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1110        but give a compile time error if the value is greater than 0xff.
1112    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1113        accidentally not being installed or uninstalled.
1115    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1116        made were to insert the current release number. This seemed silly, because
1117        it made things harder for people building PCRE on systems that don't run
1118        "configure". I have turned pcre.h into a distributed file, no longer built
1119        by "configure", with the version identification directly included. There is
1120        no longer a pcre.h.in file.
1122        However, this change necessitated a change to the pcre-config script as
1123        well. It is built from pcre-config.in, and one of the substitutions was the
1124        release number. I have updated configure.ac so that ./configure now finds
1125        the release number by grepping pcre.h.
1127    26. Added the ability to run the tests under valgrind.
1130    Version 6.4 05-Sep-05
1131    ---------------------
1133     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1134        "--" to be printed when multiple files were scanned, even when none of the
1135        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1136        consider it to be a bug, and have restored the previous behaviour.
1138     2. A couple of code tidies to get rid of compiler warnings.
1140     3. The pcretest program used to cheat by referring to symbols in the library
1141        whose names begin with _pcre_. These are internal symbols that are not
1142        really supposed to be visible externally, and in some environments it is
1143        possible to suppress them. The cheating is now confined to including
1144        certain files from the library's source, which is a bit cleaner.
1146     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1147        file's purpose clearer.
1149     5. Reorganized pcre_ucp_findchar().
1152    Version 6.3 15-Aug-05
1153    ---------------------
1155     1. The file libpcre.pc.in did not have general read permission in the tarball.
1157     2. There were some problems when building without C++ support:
1159        (a) If C++ support was not built, "make install" and "make test" still
1160            tried to test it.
1162        (b) There were problems when the value of CXX was explicitly set. Some
1163            changes have been made to try to fix these, and ...
1165        (c) --disable-cpp can now be used to explicitly disable C++ support.
1167        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1168            backslash in a target when C++ was disabled. This confuses some
1169            versions of "make", apparently. Using an intermediate variable solves
1170            this. (Same for CPP_LOBJ.)
1172     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1173        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1174        necessary on certain architectures.
1176     4. Added a setting of -export-symbols-regex to the link command to remove
1177        those symbols that are exported in the C sense, but actually are local
1178        within the library, and not documented. Their names all begin with
1179        "_pcre_". This is not a perfect job, because (a) we have to except some
1180        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1181        available (and never for static libraries). I have made a note to try to
1182        find a way round (a) in the future.
1185    Version 6.2 01-Aug-05
1186    ---------------------
1188     1. There was no test for integer overflow of quantifier values. A construction
1189        such as {1111111111111111} would give undefined results. What is worse, if
1190        a minimum quantifier for a parenthesized subpattern overflowed and became
1191        negative, the calculation of the memory size went wrong. This could have
1192        led to memory overwriting.
1194     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1196     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1197        operating environments where this matters.
1199     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1200        PCRE options from within the C++ wrapper.
1202     5. Named capturing subpatterns were not being correctly counted when a pattern
1203        was compiled. This caused two problems: (a) If there were more than 100
1204        such subpatterns, the calculation of the memory needed for the whole
1205        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1206        back references of the form \12, where the number was greater than 9, were
1207        not recognized as back references, even though there were sufficient
1208        previous subpatterns.
1210     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1211        versions of gcc, e.g. 2.95.4.
1214    Version 6.1 21-Jun-05
1215    ---------------------
1217     1. There was one reference to the variable "posix" in pcretest.c that was not
1218        surrounded by "#if !defined NOPOSIX".
1220     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1221        the cross-check on the old pcre_info() function, for the benefit of the
1222        cut-down version of PCRE that is currently imported into Exim.
1224     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1225        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1226        patterns that start (?i) but I don't think that matters. The use of (?i) is
1227        just an example; this all applies to the other options as well.
1229     4. Since libtool seems to echo the compile commands it is issuing, the output
1230        from "make" can be reduced a bit by putting "@" in front of each libtool
1231        compile command.
1233     5. Patch from the folks at Google for configure.in to be a bit more thorough
1234        in checking for a suitable C++ installation before trying to compile the
1235        C++ stuff. This should fix a reported problem when a compiler was present,
1236        but no suitable headers.
1238     6. The man pages all had just "PCRE" as their title. I have changed them to
1239        be the relevant file name. I have also arranged that these names are
1240        retained in the file doc/pcre.txt, which is a concatenation in text format
1241        of all the man pages except the little individual ones for each function.
1243     7. The NON-UNIX-USE file had not been updated for the different set of source
1244        files that come with release 6. I also added a few comments about the C++
1245        wrapper.
1248    Version 6.0 07-Jun-05
1249    ---------------------
1251     1. Some minor internal re-organization to help with my DFA experiments.
1253     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1254        didn't matter for the library itself when fully configured, but did matter
1255        when compiling without UCP support, or within Exim, where the ucp files are
1256        not imported.
1258     3. Refactoring of the library code to split up the various functions into
1259        different source modules. The addition of the new DFA matching code (see
1260        below) to a single monolithic source would have made it really too
1261        unwieldy, quite apart from causing all the code to be include in a
1262        statically linked application, when only some functions are used. This is
1263        relevant even without the DFA addition now that patterns can be compiled in
1264        one application and matched in another.
1266        The downside of splitting up is that there have to be some external
1267        functions and data tables that are used internally in different modules of
1268        the library but which are not part of the API. These have all had their
1269        names changed to start with "_pcre_" so that they are unlikely to clash
1270        with other external names.
1272     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1273        a different (DFA) algorithm. Although it is slower than the original
1274        function, it does have some advantages for certain types of matching
1275        problem.
1277     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1278        including restarting after a partial match.
1280     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1281        defined when compiling for Windows was sent to me. I have put it into the
1282        code, though I have no means of testing or verifying it.
1284     7. Added the pcre_refcount() auxiliary function.
1286     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1287        match before or at the first newline in the subject string. In pcretest,
1288        the /f option on a pattern can be used to set this.
1290     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1291        would behave wrongly. This has been present in PCRE since release 4.0.
1293    10. A number of changes to the pcregrep command:
1295        (a) Refactored how -x works; insert ^(...)$ instead of setting
1296            PCRE_ANCHORED and checking the length, in preparation for adding
1297            something similar for -w.
1299        (b) Added the -w (match as a word) option.
1301        (c) Refactored the way lines are read and buffered so as to have more
1302            than one at a time available.
1304        (d) Implemented a pcregrep test script.
1306        (e) Added the -M (multiline match) option. This allows patterns to match
1307            over several lines of the subject. The buffering ensures that at least
1308            8K, or the rest of the document (whichever is the shorter) is available
1309            for matching (and similarly the previous 8K for lookbehind assertions).
1311        (f) Changed the --help output so that it now says
1313              -w, --word-regex(p)
1315            instead of two lines, one with "regex" and the other with "regexp"
1316            because that confused at least one person since the short forms are the
1317            same. (This required a bit of code, as the output is generated
1318            automatically from a table. It wasn't just a text change.)
1320        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1321            option but starts with a hyphen. Could be a pattern or a path name
1322            starting with a hyphen, for instance.
1324        (h) "-" can be given as a file name to represent stdin.
1326        (i) When file names are being printed, "(standard input)" is used for
1327            the standard input, for compatibility with GNU grep. Previously
1328            "<stdin>" was used.
1330        (j) The option --label=xxx can be used to supply a name to be used for
1331            stdin when file names are being printed. There is no short form.
1333        (k) Re-factored the options decoding logic because we are going to add
1334            two more options that take data. Such options can now be given in four
1335            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1337        (l) Added the -A, -B, and -C options for requesting that lines of context
1338            around matches be printed.
1340        (m) Added the -L option to print the names of files that do not contain
1341            any matching lines, that is, the complement of -l.
1343        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1344            continue to scan other files.
1346        (o) The -s option was incorrectly implemented. For compatibility with other
1347            greps, it now suppresses the error message for a non-existent or non-
1348            accessible file (but not the return code). There is a new option called
1349            -q that suppresses the output of matching lines, which was what -s was
1350            previously doing.
1352        (p) Added --include and --exclude options to specify files for inclusion
1353            and exclusion when recursing.
1355    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1356        Hopefully, it now does.
1358    12. Missing cast in pcre_study().
1360    13. Added an "uninstall" target to the makefile.
1362    14. Replaced "extern" in the function prototypes in Makefile.in with
1363        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1364        world, but is set differently for Windows.
1366    15. Added a second compiling function called pcre_compile2(). The only
1367        difference is that it has an extra argument, which is a pointer to an
1368        integer error code. When there is a compile-time failure, this is set
1369        non-zero, in addition to the error test pointer being set to point to an
1370        error message. The new argument may be NULL if no error number is required
1371        (but then you may as well call pcre_compile(), which is now just a
1372        wrapper). This facility is provided because some applications need a
1373        numeric error indication, but it has also enabled me to tidy up the way
1374        compile-time errors are handled in the POSIX wrapper.
1376    16. Added VPATH=.libs to the makefile; this should help when building with one
1377        prefix path and installing with another. (Or so I'm told by someone who
1378        knows more about this stuff than I do.)
1380    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1381        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1382        match everything, including newlines. This is not POSIX-compatible, but
1383        somebody wanted the feature. From pcretest it can be activated by using
1384        both the P and the s flags.
1386    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1388    19. libpcre.pc was being incorrectly installed as executable.
1390    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1391        it now also looks for '\r' so that it will work unmodified on Windows.
1393    21. Added Google's contributed C++ wrapper to the distribution.
1395    22. Added some untidy missing memory free() calls in pcretest, to keep
1396        Electric Fence happy when testing.
1400    Version 5.0 13-Sep-04
1401    ---------------------
1403     1. Internal change: literal characters are no longer packed up into items
1404        containing multiple characters in a single byte-string. Each character
1405        is now matched using a separate opcode. However, there may be more than one
1406        byte in the character in UTF-8 mode.
1408     2. The pcre_callout_block structure has two new fields: pattern_position and
1409        next_item_length. These contain the offset in the pattern to the next match
1410        item, and its length, respectively.
1412     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1413        insertion of callouts before each pattern item. Added the /C option to
1414        pcretest to make use of this.
1416     4. On the advice of a Windows user, the lines
1418          #if defined(_WIN32) || defined(WIN32)
1419          _setmode( _fileno( stdout ), 0x8000 );
1420          #endif  /* defined(_WIN32) || defined(WIN32) */
1422        have been added to the source of pcretest. This apparently does useful
1423        magic in relation to line terminators.
1425     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1426        for the benefit of those environments where the "b" makes a difference.
1428     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1429        to know about it. I have put a hack into configure.in that adds in code
1430        to set GCC=yes if CC=icc. This seems to end up at a point in the
1431        generated configure script that is early enough to affect the setting of
1432        compiler options, which is what is needed, but I have no means of testing
1433        whether it really works. (The user who reported this had patched the
1434        generated configure script, which of course I cannot do.)
1436        LATER: After change 22 below (new libtool files), the configure script
1437        seems to know about icc (and also ecc). Therefore, I have commented out
1438        this hack in configure.in.
1440     7. Added support for pkg-config (2 patches were sent in).
1442     8. Negated POSIX character classes that used a combination of internal tables
1443        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1444        [[:^ascii]]. Typically, they would match almost any characters. The other
1445        POSIX classes were not broken in this way.
1447     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1448        to find the match, as PCRE was deluded into thinking that the match had to
1449        start at the start point or following a newline. The same bug applied to
1450        patterns with negative forward assertions or any backward assertions
1451        preceding ".*" at the start, unless the pattern required a fixed first
1452        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1454    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1455        starting at the last subject character, bytes beyond the end of the subject
1456        string were read.
1458    11. Renamed the variable "class" as "classbits" to make life easier for C++
1459        users. (Previously there was a macro definition, but it apparently wasn't
1460        enough.)
1462    12. Added the new field "tables" to the extra data so that tables can be passed
1463        in at exec time, or the internal tables can be re-selected. This allows
1464        a compiled regex to be saved and re-used at a later time by a different
1465        program that might have everything at different addresses.
1467    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1468        -R library as well as a -L library.
1470    14. The debugging options of pcretest (-d on the command line or D on a
1471        pattern) showed incorrect output for anything following an extended class
1472        that contained multibyte characters and which was followed by a quantifier.
1474    15. Added optional support for general category Unicode character properties
1475        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1476        support. It adds about 90K to the size of the library. The meanings of the
1477        inbuilt class escapes such as \d and \s have NOT been changed.
1479    16. Updated pcredemo.c to include calls to free() to release the memory for the
1480        compiled pattern.
1482    17. The generated file chartables.c was being created in the source directory
1483        instead of in the building directory. This caused the build to fail if the
1484        source directory was different from the building directory, and was
1485        read-only.
1487    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1488        file. No doubt somebody will tell me if they don't make sense... Also added
1489        Dan Mooney's comments about building on OpenVMS.
1491    19. Added support for partial matching via the PCRE_PARTIAL option for
1492        pcre_exec() and the \P data escape in pcretest.
1494    20. Extended pcretest with 3 new pattern features:
1496        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1497              write the compiled pattern to the file whose name is "rest-of-line".
1498              This is a straight binary dump of the data, with the saved pointer to
1499              the character tables forced to be NULL. The study data, if any, is
1500              written too. After writing, pcretest reads a new pattern.
1502        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1503              compiled pattern from the given file. There must not be any
1504              occurrences of "<" in the file name (pretty unlikely); if there are,
1505              pcretest will instead treat the initial "<" as a pattern delimiter.
1506              After reading in the pattern, pcretest goes on to read data lines as
1507              usual.
1509        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1510              and 16-bit fields in a compiled pattern, to simulate a pattern that
1511              was compiled on a host of opposite endianness.
1513    21. The pcre-exec() function can now cope with patterns that were compiled on
1514        hosts of opposite endianness, with this restriction:
1516          As for any compiled expression that is saved and used later, the tables
1517          pointer field cannot be preserved; the extra_data field in the arguments
1518          to pcre_exec() should be used to pass in a tables address if a value
1519          other than the default internal tables were used at compile time.
1521    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1522        now diagnosed as an error. Previously, most of the time, a negative number
1523        would have been treated as zero, but if in addition "ovector" was passed as
1524        NULL, a crash could occur.
1526    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1527        new versions from the libtool 1.5 distribution (the last one is a copy of
1528        a file called libtool.m4). This seems to have fixed the need to patch
1529        "configure" to support Darwin 1.3 (which I used to do). However, I still
1530        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1531        workstation).
1533    24. Changed the PCRE licence to be the more standard "BSD" licence.
1536    Version 4.5 01-Dec-03
1537    ---------------------
1539     1. There has been some re-arrangement of the code for the match() function so
1540        that it can be compiled in a version that does not call itself recursively.
1541        Instead, it keeps those local variables that need separate instances for
1542        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1543        needs to "recurse". Keeping track of where control must go is done by means
1544        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1545        hide most of the details from the main code, and operates only if
1546        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1547        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1548        operating.
1550        To make it easier for callers to provide specially tailored get/free
1551        functions for this usage, two new functions, pcre_stack_malloc, and
1552        pcre_stack_free, are used. They are always called in strict stacking order,
1553        and the size of block requested is always the same.
1555        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1556        PCRE has been compiled to use the stack or the heap for recursion. The
1557        -C option of pcretest uses this to show which version is compiled.
1559        A new data escape \S, is added to pcretest; it causes the amounts of store
1560        obtained and freed by both kinds of malloc/free at match time to be added
1561        to the output.
1563     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1564        what's available on my current Linux desktop machine.
1566     3. When matching a UTF-8 string, the test for a valid string at the start has
1567        been extended. If start_offset is not zero, PCRE now checks that it points
1568        to a byte that is the start of a UTF-8 character. If not, it returns
1569        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1570        this is necessary because there may be backward assertions in the pattern.
1571        When matching the same subject several times, it may save resources to use
1572        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1574     4. The code for checking the validity of UTF-8 strings has been tightened so
1575        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1576        containing "overlong sequences".
1578     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1579        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1580        should have been "&", but it just so happened that all the cases this let
1581        through by mistake were picked up later in the function.
1583     6. I had used a variable called "isblank" - this is a C99 function, causing
1584        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1586     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1587        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1588        so the version is shown; (c) stop "make test" echoing "./RunTest".
1590     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1592     9. The prototype for memmove() for systems that don't have it was using
1593        size_t, but the inclusion of the header that defines size_t was later. I've
1594        moved the #includes for the C headers earlier to avoid this.
1596    10. Added some adjustments to the code to make it easier to compiler on certain
1597        special systems:
1599          (a) Some "const" qualifiers were missing.
1600          (b) Added the macro EXPORT before all exported functions; by default this
1601              is defined to be empty.
1602          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1603              that it reads its output file name as an argument instead of writing
1604              to the standard output and assuming this can be redirected.
1606    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1607        class containing characters with values greater than 255, PCRE compilation
1608        went into a loop.
1610    12. A recursive reference to a subpattern that was within another subpattern
1611        that had a minimum quantifier of zero caused PCRE to crash. For example,
1612        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1613        recursion. If the recursively-called subpattern itself had a zero repeat,
1614        that was OK.
1616    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1617        buffer into which it was copied (for escape processing) was still set at
1618        1024, so long lines caused crashes.
1620    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1621        "internal error: code overflow...". This applied to any character class
1622        that was followed by a possessive quantifier.
1624    15. Modified the Makefile to add libpcre.la as a prerequisite for
1625        libpcreposix.la because I was told this is needed for a parallel build to
1626        work.
1628    16. If a pattern that contained .* following optional items at the start was
1629        studied, the wrong optimizing data was generated, leading to matching
1630        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1631        matching string must start with a or b or c. The correct conclusion for
1632        this pattern is that a match can start with any character.
1635    Version 4.4 13-Aug-03
1636    ---------------------
1638     1. In UTF-8 mode, a character class containing characters with values between
1639        127 and 255 was not handled correctly if the compiled pattern was studied.
1640        In fixing this, I have also improved the studying algorithm for such
1641        classes (slightly).
1643     2. Three internal functions had redundant arguments passed to them. Removal
1644        might give a very teeny performance improvement.
1646     3. Documentation bug: the value of the capture_top field in a callout is *one
1647        more than* the number of the hightest numbered captured substring.
1649     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1650        in incorrectly linking with a previously installed version. They now link
1651        explicitly with libpcre.la.
1653     5. configure.in no longer needs to recognize Cygwin specially.
1655     6. A problem in pcre.in for Windows platforms is fixed.
1657     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1658        pcretest, it used to include the size of the study block as part of its
1659        output. Unfortunately, the structure contains a field that has a different
1660        size on different hardware architectures. This meant that the tests that
1661        showed this size failed. As the block is currently always of a fixed size,
1662        this information isn't actually particularly useful in pcretest output, so
1663        I have just removed it.
1665     8. Three pre-processor statements accidentally did not start in column 1.
1666        Sadly, there are *still* compilers around that complain, even though
1667        standard C has not required this for well over a decade. Sigh.
1669     9. In pcretest, the code for checking callouts passed small integers in the
1670        callout_data field, which is a void * field. However, some picky compilers
1671        complained about the casts involved for this on 64-bit systems. Now
1672        pcretest passes the address of the small integer instead, which should get
1673        rid of the warnings.
1675    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1676        both compile and run time, and gives an error if an invalid UTF-8 sequence
1677        is found. There is a option for disabling this check in cases where the
1678        string is known to be correct and/or the maximum performance is wanted.
1680    11. In response to a bug report, I changed one line in Makefile.in from
1682            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1683        to
1684            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1686        to look similar to other lines, but I have no way of telling whether this
1687        is the right thing to do, as I do not use Windows. No doubt I'll get told
1688        if it's wrong...
1691    Version 4.3 21-May-03
1692    ---------------------
1694    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1695       Makefile.
1697    2. Some refactoring to improve the quality of the code:
1699       (i)   The utf8_table... variables are now declared "const".
1701       (ii)  The code for \cx, which used the "case flipping" table to upper case
1702             lower case letters, now just substracts 32. This is ASCII-specific,
1703             but the whole concept of \cx is ASCII-specific, so it seems
1704             reasonable.
1706       (iii) PCRE was using its character types table to recognize decimal and
1707             hexadecimal digits in the pattern. This is silly, because it handles
1708             only 0-9, a-f, and A-F, but the character types table is locale-
1709             specific, which means strange things might happen. A private
1710             table is now used for this - though it costs 256 bytes, a table is
1711             much faster than multiple explicit tests. Of course, the standard
1712             character types table is still used for matching digits in subject
1713             strings against \d.
1715       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1716             ending in _t are). So I've renamed it as ESC_tee.
1718    3. The first argument for regexec() in the POSIX wrapper should have been
1719       defined as "const".
1721    4. Changed pcretest to use malloc() for its buffers so that they can be
1722       Electric Fenced for debugging.
1724    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1725       to read one or more bytes before the start of the subject string. Often this
1726       had no effect on PCRE's behaviour, but in some circumstances it could
1727       provoke a segmentation fault.
1729    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1730       to try to read one or more bytes before the start of the subject string.
1732    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1733       UTF-8 support could misbehave in various ways if the subject string
1734       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1735       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1736       back over UTF-8 characters.)
1739    Version 4.2 14-Apr-03
1740    ---------------------
1742    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1744    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1745         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1746         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1747         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1748         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1749           and BUILD_EXEEXT
1750         Note: automatic setting of the BUILD variables is not yet working
1751         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1752           compile-time but not at link-time
1753         [LINK]: use for linking executables only
1754         make different versions for Windows and non-Windows
1755         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1756           libraries
1757         [LINK_FOR_BUILD]: new variable
1758         [OBJEXT]: use throughout
1759         [EXEEXT]: use throughout
1760         <winshared>: new target
1761         <wininstall>: new target
1762         <dftables.o>: use native compiler
1763         <dftables>: use native linker
1764         <install>: handle Windows platform correctly
1765         <clean>: ditto
1766         <check>: ditto
1767         copy DLL to top builddir before testing
1769       As part of these changes, -no-undefined was removed again. This was reported
1770       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1771       in any case.
1773    3. Some tidies to get rid of compiler warnings:
1775       . In the match_data structure, match_limit was an unsigned long int, whereas
1776         match_call_count was an int. I've made them both unsigned long ints.
1778       . In pcretest the fact that a const uschar * doesn't automatically cast to
1779         a void * provoked a warning.
1781       . Turning on some more compiler warnings threw up some "shadow" variables
1782         and a few more missing casts.
1784    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1785       option, a class that contained a single character with a value between 128
1786       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1788    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1789       option, a class that contained several characters, but with at least one
1790       whose value was between 128 and 255 caused PCRE to crash.
1793    Version 4.1 12-Mar-03
1794    ---------------------
1796    1. Compiling with gcc -pedantic found a couple of places where casts were
1797    needed, and a string in dftables.c that was longer than standard compilers are
1798    required to support.
1800    2. Compiling with Sun's compiler found a few more places where the code could
1801    be tidied up in order to avoid warnings.
1803    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1804    first of these names is deprecated in the latest Autoconf in favour of the name
1805    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1806    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1807    analogy I have changed it to CFLAGS_FOR_BUILD.
1809    4. Added -no-undefined to the linking command in the Makefile, because this is
1810    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1811    linking step for the pcreposix library.
1813    5. PCRE was failing to diagnose the case of two named groups with the same
1814    name.
1816    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1817    literal character that is needed in the subject for a match, and scans along to
1818    ensure that it is present before embarking on the full matching process. This
1819    saves time in cases of nested unlimited repeats that are never going to match.
1820    Problem: the scan can take a lot of time if the subject is very long (e.g.
1821    megabytes), thus penalizing straightforward matches. It is now done only if the
1822    amount of subject to be scanned is less than 1000 bytes.
1824    7. A lesser problem with the same optimization is that it was recording the
1825    first character of an anchored pattern as "needed", thus provoking a search
1826    right along the subject, even when the first match of the pattern was going to
1827    fail. The "needed" character is now not set for anchored patterns, unless it
1828    follows something in the pattern that is of non-fixed length. Thus, it still
1829    fulfils its original purpose of finding quick non-matches in cases of nested
1830    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1833    Version 4.0 17-Feb-03
1834    ---------------------
1836    1. If a comment in an extended regex that started immediately after a meta-item
1837    extended to the end of string, PCRE compiled incorrect data. This could lead to
1838    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1840    2. Moved to autoconf 2.53 and libtool 1.4.2.
1842    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1843    the special perltest8 script is no longer needed - all the tests can be run
1844    from a single perltest script.
1846    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1847    by \s. It has now been removed in PCRE. This means it isn't recognized as
1848    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1849    class [:space:] *does* include VT, thereby creating a mess.
1851    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1852    space and tab.
1854    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1855    its new features into the main test script, reducing the number of scripts.
1857    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1858    were backward compatible, and made the (?i) apply to the whole pattern, as if
1859    /i were given. Now it behaves more logically, and applies the option setting
1860    only to what follows. PCRE has been changed to follow suit. However, if it
1861    finds options settings right at the start of the pattern, it extracts them into
1862    the global options, as before. Thus, they show up in the info data.
1864    8. Added support for the \Q...\E escape sequence. Characters in between are
1865    treated as literals. This is slightly different from Perl in that $ and @ are
1866    also handled as literals inside the quotes. In Perl, they will cause variable
1867    interpolation. Note the following examples:
1869        Pattern            PCRE matches      Perl matches
1871        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1872        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1873        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1875    For compatibility with Perl, \Q...\E sequences are recognized inside character
1876    classes as well as outside them.
1878    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1879    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1880    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1881    signed/unsigned warnings.
1883    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1884    option for pcretest, so I've replaced it by a simple function that does just
1885    that job.
1887    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1888    "pcregrep -".
1890    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1891    Java package. This provides some syntactic sugar for simple cases of what my
1892    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1893    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1894    item, you can use this simplified notation. Note that only makes sense with
1895    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1896    greediness, whatever the setting of the PCRE_UNGREEDY option.
1898    13. A change of greediness default within a pattern was not taking effect at
1899    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1900    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1901    was abstracted outside.
1903    14. PCRE now supports the \G assertion. It is true when the current matching
1904    position is at the start point of the match. This differs from \A when the
1905    starting offset is non-zero. Used with the /g option of pcretest (or similar
1906    code), it works in the same way as it does for Perl's /g option. If all
1907    alternatives of a regex begin with \G, the expression is anchored to the start
1908    match position, and the "anchored" flag is set in the compiled expression.
1910    15. Some bugs concerning the handling of certain option changes within patterns
1911    have been fixed. These applied to options other than (?ims). For example,
1912    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1913    been the other way round. Some of this was related to change 7 above.
1915    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1916    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1917    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1918    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1920    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1921    mode. Unlike ".", it always matches newline, whatever the setting of
1922    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1923    assertions. Perl allows it, but it doesn't (in general) work because it can't
1924    calculate the length of the lookbehind. At least, that's the case for Perl
1925    5.8.0 - I've been told they are going to document that it doesn't work in
1926    future.
1928    18. Added an error diagnosis for escapes that PCRE does not support: these are
1929    \L, \l, \N, \P, \p, \U, \u, and \X.
1931    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1932    reading past the end of the pattern in cases such as /[abcd/.
1934    20. PCRE was getting more memory than necessary for patterns with classes that
1935    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1937    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1938    compiling PCRE for use with Virtual Pascal.
1940    22. Small fix to the Makefile to make it work properly if the build is done
1941    outside the source tree.
1943    23. Added a new extension: a condition to go with recursion. If a conditional
1944    subpattern starts with (?(R) the "true" branch is used if recursion has
1945    happened, whereas the "false" branch is used only at the top level.
1947    24. When there was a very long string of literal characters (over 255 bytes
1948    without UTF support, over 250 bytes with UTF support), the computation of how
1949    much memory was required could be incorrect, leading to segfaults or other
1950    strange effects.
1952    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1953    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1954    there was a subsequent back reference to those brackets. This meant that, for
1955    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1956    possible to check for precisely this case. All we can do is abandon the
1957    optimization if .* occurs inside capturing brackets when there are any back
1958    references whatsoever. (See below for a better fix that came later.)
1960    26. The handling of the optimization for finding the first character of a
1961    non-anchored pattern, and for finding a character that is required later in the
1962    match were failing in some cases. This didn't break the matching; it just
1963    failed to optimize when it could. The way this is done has been re-implemented.
1965    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1967    28. Added a new feature that provides some of the functionality that Perl
1968    provides with (?{...}). The facility is termed a "callout". The way it is done
1969    in PCRE is for the caller to provide an optional function, by setting
1970    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1971    global variable. By default it is unset, which disables all calling out. To get
1972    the function called, the regex must include (?C) at appropriate points. This
1973    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1974    This provides a means of identifying different callout points. When PCRE
1975    reaches such a point in the regex, if pcre_callout has been set, the external
1976    function is called. It is provided with data in a structure called
1977    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1978    matching continues; if it returns a non-zero value, the match at the current
1979    point fails. However, backtracking will occur if possible. [This was changed
1980    later and other features added - see item 49 below.]
1982    29. pcretest is upgraded to test the callout functionality. It provides a
1983    callout function that displays information. By default, it shows the start of
1984    the match and the current position in the text. There are some new data escapes
1985    to vary what happens:
1987        \C+         in addition, show current contents of captured substrings
1988        \C-         do not supply a callout function
1989        \C!n        return 1 when callout number n is reached
1990        \C!n!m      return 1 when callout number n is reached for the mth time
1992    30. If pcregrep was called with the -l option and just a single file name, it
1993    output "<stdin>" if a match was found, instead of the file name.
1995    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1996    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1997    pcre_exec(). This saves a malloc/free per call. The default value of
1998    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1999    when configuring.
2001    32. The default maximum size of a compiled pattern is 64K. There have been a
2002    few cases of people hitting this limit. The code now uses macros to handle the
2003    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2004    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2005    configuring. Tests 2 and 5 work only with 2-byte links because they output
2006    debugging information about compiled patterns.
2008    33. Internal code re-arrangements:
2010    (a) Moved the debugging function for printing out a compiled regex into
2011        its own source file (printint.c) and used #include to pull it into
2012        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2013        separate copies.
2015    (b) Defined the list of op-code names for debugging as a macro in
2016        internal.h so that it is next to the definition of the opcodes.
2018    (c) Defined a table of op-code lengths for simpler skipping along compiled
2019        code. This is again a macro in internal.h so that it is next to the
2020        definition of the opcodes.
2022    34. Added support for recursive calls to individual subpatterns, along the
2023    lines of Robin Houston's patch (but implemented somewhat differently).
2025    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2026    allow it to read and process whole directories in Win32. This code was
2027    contributed by Lionel Fourquaux; it has not been tested by me.
2029    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2030    used to name a group. Names consist of alphanumerics and underscores, and must
2031    be unique. Back references use the syntax (?P=name) and recursive calls use
2032    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2033    numbers. The function pcre_fullinfo() can be used after compilation to extract
2034    a name/number map. There are three relevant calls:
2036      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2037      PCRE_INFO_NAMECOUNT            yields the number of entries
2038      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2040    The map is a vector of fixed-size entries. The size of each entry depends on
2041    the length of the longest name used. The first two bytes of each entry are the
2042    group number, most significant byte first. There follows the corresponding
2043    name, zero terminated. The names are in alphabetical order.
2045    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2046    case instead of 255. Making it the same both with and without UTF-8 support
2047    means that the same test output works with both.
2049    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2050    calling malloc() with a zero argument.
2052    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2053    optimization. I've improved things by keeping a bitmap of backreferences with
2054    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2055    fact referenced, the optimization can be applied. It is unlikely that a
2056    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2057    the match to follow \n) will appear inside brackets with a number greater than
2058    31, but if it does, any back reference > 31 suppresses the optimization.
2060    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2061    of disabling numbered capturing parentheses. Any opening parenthesis that is
2062    not followed by ? behaves as if it were followed by ?: but named parentheses
2063    can still be used for capturing (and they will acquire numbers in the usual
2064    way).
2066    41. Redesigned the return codes from the match() function into yes/no/error so
2067    that errors can be passed back from deep inside the nested calls. A malloc
2068    failure while inside a recursive subpattern call now causes the
2069    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2071    42. It is now possible to set a limit on the number of times the match()
2072    function is called in a call to pcre_exec(). This facility makes it possible to
2073    limit the amount of recursion and backtracking, though not in a directly
2074    obvious way, because the match() function is used in a number of different
2075    circumstances. The count starts from zero for each position in the subject
2076    string (for non-anchored patterns). The default limit is, for compatibility, a
2077    large number, namely 10 000 000. You can change this in two ways:
2079    (a) When configuring PCRE before making, you can use --with-match-limit=n
2080        to set a default value for the compiled library.
2082    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2083        a different value is set. See 45 below.
2085    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2087    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2088    of things that can be changed at compile time. The first argument specifies
2089    what is wanted and the second points to where the information is to be placed.
2090    The current list of available information is:
2092      PCRE_CONFIG_UTF8
2094    The output is an integer that is set to one if UTF-8 support is available;
2095    otherwise it is set to zero.
2099    The output is an integer that it set to the value of the code that is used for
2100    newline. It is either LF (10) or CR (13).
2104    The output is an integer that contains the number of bytes used for internal
2105    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2109    The output is an integer that contains the threshold above which the POSIX
2110    interface uses malloc() for output vectors. See item 31 above.
2114    The output is an unsigned integer that contains the default limit of the number
2115    of match() calls in a pcre_exec() execution. See 42 above.
2117    44. pcretest has been upgraded by the addition of the -C option. This causes it
2118    to extract all the available output from the new pcre_config() function, and to
2119    output it. The program then exits immediately.
2121    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2122    order to support additional features. One way would have been to define
2123    pcre_exec2() (for example) with extra arguments, but this would not have been
2124    extensible, and would also have required all calls to the original function to
2125    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2126    is used for passing in "extra" data from pcre_study().
2128    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2129    contains the following fields:
2131      flags         a bitmap indicating which of the following fields are set
2132      study_data    opaque data from pcre_study()
2133      match_limit   a way of specifying a limit on match() calls for a specific
2134                      call to pcre_exec()
2135      callout_data  data for callouts (see 49 below)
2137    The flag bits are also defined in pcre.h, and are
2143    The pcre_study() function now returns one of these new pcre_extra blocks, with
2144    the actual study data pointed to by the study_data field, and the
2145    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2146    before. That is, this change is entirely upwards-compatible and requires no
2147    change to existing code.
2149    If you want to pass in additional data to pcre_exec(), you can either place it
2150    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2151    block.
2153    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2154    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2155    times with different match limits, until it finds the minimum value needed for
2156    pcre_exec() to complete. The value is then output. This can be instructive; for
2157    most simple matches the number is quite small, but for pathological cases it
2158    gets very large very quickly.
2160    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2161    returns the size of the data block pointed to by the study_data field in a
2162    pcre_extra block, that is, the value that was passed as the argument to
2163    pcre_malloc() when PCRE was getting memory in which to place the information
2164    created by pcre_study(). The fourth argument should point to a size_t variable.
2165    pcretest has been extended so that this information is shown after a successful
2166    pcre_study() call when information about the compiled regex is being displayed.
2168    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2169    because what follows is always an absolute path. (Later: it turns out that this
2170    is more than cosmetic for MinGW, because it doesn't like empty path
2171    components.)
2173    49. Some changes have been made to the callout feature (see 28 above):
2175    (i)  A callout function now has three choices for what it returns:
2177           0  =>  success, carry on matching
2178         > 0  =>  failure at this point, but backtrack if possible
2179         < 0  =>  serious error, return this value from pcre_exec()
2181         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2182         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2183         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2184         use by callout functions. It will never be used by PCRE itself.
2186    (ii) The pcre_extra structure (see 45 above) has a void * field called
2187         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2188         pcre_callout_block structure has a field of the same name. The contents of
2189         the field passed in the pcre_extra structure are passed to the callout
2190         function in the corresponding field in the callout block. This makes it
2191         easier to use the same callout-containing regex from multiple threads. For
2192         testing, the pcretest program has a new data escape
2194           \C*n        pass the number n (may be negative) as callout_data
2196         If the callout function in pcretest receives a non-zero value as
2197         callout_data, it returns that value.
2199    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2200    there were some redundant $(CFLAGS) in commands that are now specified as
2201    $(LINK), which already includes $(CFLAGS).
2203    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2204    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2205    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2206    one-byte characters throughout. Note that case-insensitive matching applies
2207    only to characters whose values are less than 256. PCRE doesn't support the
2208    notion of cases for higher-valued characters.
2210    (i)   A character class whose characters are all within 0-255 is handled as
2211          a bit map, and the map is inverted for negative classes. Previously, a
2212          character > 255 always failed to match such a class; however it should
2213          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2215    (ii)  A negated character class with a single character < 255 is coded as
2216          "not this character" (OP_NOT). This wasn't working properly when the test
2217          character was multibyte, either singly or repeated.
2219    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2220          mode, for example: \x{100}{2,3}.
2222    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2223          singly or repeated) now correctly test multibyte characters. However,
2224          PCRE doesn't recognize any characters with values greater than 255 as
2225          digits, spaces, or word characters. Such characters always match \D, \S,
2226          and \W, and never match \d, \s, or \w.
2228    (v)   Classes may now contain characters and character ranges with values
2229          greater than 255. For example: [ab\x{100}-\x{400}].
2231    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2232          PCRE in UTF-8 mode.
2234    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2235    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2236    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2237    value.)
2239    53. The single man page has become too large. I have therefore split it up into
2240    a number of separate man pages. These also give rise to individual HTML pages;
2241    these are now put in a separate directory, and there is an index.html page that
2242    lists them all. Some hyperlinking between the pages has been installed.
2244    54. Added convenience functions for handling named capturing parentheses.
2246    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2247    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2248    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2249    are faulted.
2251    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2252    calling configure. These values are used when compiling the dftables.c program
2253    which is run to generate the source of the default character tables. They
2254    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2255    you will need to set these values.
2257    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2260    Version 3.9 02-Jan-02
2261    ---------------------
2263    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2265    2. If --disable-static was given, the building process failed when trying to
2266    build pcretest and pcregrep. (For some reason it was using libtool to compile
2267    them, which is not right, as they aren't part of the library.)
2270    Version 3.8 18-Dec-01
2271    ---------------------
2273    1. The experimental UTF-8 code was completely screwed up. It was packing the
2274    bytes in the wrong order. How dumb can you get?
2277    Version 3.7 29-Oct-01
2278    ---------------------
2280    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2281    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2282    this didn't happen under Solaris 8, where I normally test things.
2284    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2285    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2286    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2287    this fix an hour or so after the initial 3.7 release.)
2290    Version 3.6 23-Oct-01
2291    ---------------------
2293    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2294    offsets passed as NULL with zero offset count.
2296    2. The config.guess and config.sub files had not been updated when I moved to
2297    the latest autoconf.
2300    Version 3.5 15-Aug-01
2301    ---------------------
2303    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2304    had been forgotten.
2306    2. By using declared but undefined structures, we can avoid using "void"
2307    definitions in pcre.h while keeping the internal definitions of the structures
2308    private.
2310    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2311    user point of view, this means that both static and shared libraries are built
2312    by default, but this can be individually controlled. More of the work of
2313    handling this static/shared cases is now inside libtool instead of PCRE's make
2314    file.
2316    4. The pcretest utility is now installed along with pcregrep because it is
2317    useful for users (to test regexs) and by doing this, it automatically gets
2318    relinked by libtool. The documentation has been turned into a man page, so
2319    there are now .1, .txt, and .html versions in /doc.
2321    5. Upgrades to pcregrep:
2322       (i)   Added long-form option names like gnu grep.
2323       (ii)  Added --help to list all options with an explanatory phrase.
2324       (iii) Added -r, --recursive to recurse into sub-directories.
2325       (iv)  Added -f, --file to read patterns from a file.
2327    6. pcre_exec() was referring to its "code" argument before testing that
2328    argument for NULL (and giving an error if it was NULL).
2330    7. Upgraded Makefile.in to allow for compiling in a different directory from
2331    the source directory.
2333    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2334    options bits, the pointer it was passed was to an int instead of to an unsigned
2335    long int. This mattered only on 64-bit systems.
2337    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2338    generated) instead of pcre.in, which it its source. Also made the same change
2339    in several of the .c files.
2341    10. A new release of gcc defines printf() as a macro, which broke pcretest
2342    because it had an ifdef in the middle of a string argument for printf(). Fixed
2343    by using separate calls to printf().
2345    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2346    script, to force use of CR or LF instead of \n in the source. On non-Unix
2347    systems, the value can be set in config.h.
2349    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2350    absolute limit. Changed the text of the error message to make this clear, and
2351    likewise updated the man page.
2353    13. The limit of 99 on the number of capturing subpatterns has been removed.
2354    The new limit is 65535, which I hope will not be a "real" limit.
2357    Version 3.4 22-Aug-00
2358    ---------------------
2360    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2362    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2365    Version 3.3 01-Aug-00
2366    ---------------------
2368    1. If an octal character was given, but the value was greater than \377, it
2369    was not getting masked to the least significant bits, as documented. This could
2370    lead to crashes in some systems.
2372    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2373    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2375    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2376    These just pass their arguments on to (pcre_free)(), but they are provided
2377    because some uses of PCRE bind it to non-C systems that can call its functions,
2378    but cannot call free() or pcre_free() directly.
2380    4. Add "make test" as a synonym for "make check". Corrected some comments in
2381    the Makefile.
2383    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2384    Makefile.
2386    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2387    command called pgrep for grepping around the active processes.
2389    7. Added the beginnings of support for UTF-8 character strings.
2391    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2392    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2393    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2394    out for the ar command.)
2397  Version 3.2 12-May-00  Version 3.2 12-May-00
2398  ---------------------  ---------------------

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