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revision 69 by nigel, Sat Feb 24 21:40:18 2007 UTC revision 279 by ph10, Tue Dec 4 20:01:43 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 12-Nov-07
5    ---------------------
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
80    Version 7.4 21-Sep-07
81    ---------------------
83    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
84        means that a class such as [\s] counted as "explicit reference to CR or
85        LF". That isn't really right - the whole point of the change was to try to
86        help when there was an actual mention of one of the two characters. So now
87        the change happens only if \r or \n (or a literal CR or LF) character is
88        encountered.
90    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
91        of both had grown to the point where there were only 3 bits left.
92        Fortunately, there was spare space in the data structure, and so I have
93        moved the internal flags into a new 16-bit field to free up more option
94        bits.
96    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
97        but did not set the internal JCHANGED flag - either of these is enough to
98        control the way the "get" function works - but the PCRE_INFO_JCHANGED
99        facility is supposed to tell if (?J) was ever used, so now (?J) at the
100        start sets both bits.
102    4.  Added options (at build time, compile time, exec time) to change \R from
103        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
105    5.  doc/pcresyntax.html was missing from the distribution.
107    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
108        compatibility, even though it is no longer used.
110    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
111        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
112        windows.h file is present (where different names are used). [This was
113        reversed later after testing - see 16 below.]
115    8.  Changed all #include <config.h> to #include "config.h". There were also
116        some further <pcre.h> cases that I changed to "pcre.h".
118    9.  When pcregrep was used with the --colour option, it missed the line ending
119        sequence off the lines that it output.
121    10. It was pointed out to me that arrays of string pointers cause lots of
122        relocations when a shared library is dynamically loaded. A technique of
123        using a single long string with a table of offsets can drastically reduce
124        these. I have refactored PCRE in four places to do this. The result is
125        dramatic:
127          Originally:                          290
128          After changing UCP table:            187
129          After changing error message table:   43
130          After changing table of "verbs"       36
131          After changing table of Posix names   22
133        Thanks to the folks working on Gregex for glib for this insight.
135    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
136        unicode-properties was also set.
138    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
140    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
141        checked only for CRLF.
143    14. Added casts to pcretest.c to avoid compiler warnings.
145    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
147    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
148        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
149        entirely. This removes changes made in 7 above.
151    17. The CMake files have been updated, and there is now more information about
152        building with CMake in the NON-UNIX-USE document.
155    Version 7.3 28-Aug-07
156    ---------------------
158     1. In the rejigging of the build system that eventually resulted in 7.1, the
159        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
160        brackets there is not right, since it causes compilers to look for an
161        installed pcre.h, not the version that is in the source that is being
162        compiled (which of course may be different). I have changed it back to:
164          #include "pcre.h"
166        I have a vague recollection that the change was concerned with compiling in
167        different directories, but in the new build system, that is taken care of
168        by the VPATH setting the Makefile.
170     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
171        when the subject happened to end in the byte 0x85 (e.g. if the last
172        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
173        characters but of course it shouldn't be taken as a newline when it is part
174        of another character. The bug was that, for an unlimited repeat of . in
175        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
176        characters when looking for a newline.
178     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
180     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
181        in debug output.
183     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
184        long printing in the pcrecpp unittest when running under MinGW.
186     6. ESC_K was left out of the EBCDIC table.
188     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
189        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
190        limit also applies to "virtual nesting" when a pattern is recursive, and in
191        this case 1000 isn't so big. I have been able to remove this limit at the
192        expense of backing off one optimization in certain circumstances. Normally,
193        when pcre_exec() would call its internal match() function recursively and
194        immediately return the result unconditionally, it uses a "tail recursion"
195        feature to save stack. However, when a subpattern that can match an empty
196        string has an unlimited repetition quantifier, it no longer makes this
197        optimization. That gives it a stack frame in which to save the data for
198        checking that an empty string has been matched. Previously this was taken
199        from the 1000-entry workspace that had been reserved. So now there is no
200        explicit limit, but more stack is used.
202     8. Applied Daniel's patches to solve problems with the import/export magic
203        syntax that is required for Windows, and which was going wrong for the
204        pcreposix and pcrecpp parts of the library. These were overlooked when this
205        problem was solved for the main library.
207     9. There were some crude static tests to avoid integer overflow when computing
208        the size of patterns that contain repeated groups with explicit upper
209        limits. As the maximum quantifier is 65535, the maximum group length was
210        set at 30,000 so that the product of these two numbers did not overflow a
211        32-bit integer. However, it turns out that people want to use groups that
212        are longer than 30,000 bytes (though not repeat them that many times).
213        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
214        made it possible to implement the integer overflow checks in a much more
215        dynamic way, which I have now done. The artificial limitation on group
216        length has been removed - we now have only the limit on the total length of
217        the compiled pattern, which depends on the LINK_SIZE setting.
219    10. Fixed a bug in the documentation for get/copy named substring when
220        duplicate names are permitted. If none of the named substrings are set, the
221        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
222        empty string.
224    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
225        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
226        because the ] is interpreted as the first data character and the
227        terminating ] is not found. PCRE has been made compatible with Perl in this
228        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
229        cause memory overwriting.
231    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
232        string has been matched (to stop an infinite loop). It was not recognizing
233        a conditional subpattern that could match an empty string if that
234        subpattern was within another subpattern. For example, it looped when
235        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
236        condition was not nested. This bug has been fixed.
238    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
239        past the start of the subject in the presence of bytes with the top bit
240        set, for example "\x8aBCD".
242    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
243        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
245    14. Optimized (?!) to (*FAIL).
247    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
248        This restricts code points to be within the range 0 to 0x10FFFF, excluding
249        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
250        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
251        does: it's just the validity check that is more restrictive.
253    16. Inserted checks for integer overflows during escape sequence (backslash)
254        processing, and also fixed erroneous offset values for syntax errors during
255        backslash processing.
257    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
258        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
260    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
261        caused an overrun.
263    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
264        something other than just ASCII characters) inside a group that had an
265        unlimited repeat caused a loop at compile time (while checking to see
266        whether the group could match an empty string).
268    20. Debugging a pattern containing \p or \P could cause a crash. For example,
269        [\P{Any}] did so. (Error in the code for printing property names.)
271    21. An orphan \E inside a character class could cause a crash.
273    22. A repeated capturing bracket such as (A)? could cause a wild memory
274        reference during compilation.
276    23. There are several functions in pcre_compile() that scan along a compiled
277        expression for various reasons (e.g. to see if it's fixed length for look
278        behind). There were bugs in these functions when a repeated \p or \P was
279        present in the pattern. These operators have additional parameters compared
280        with \d, etc, and these were not being taken into account when moving along
281        the compiled data. Specifically:
283        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
284            length.
286        (b) An item such as \pL+ within a repeated group could cause crashes or
287            loops.
289        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
290            "reference to non-existent subpattern" error.
292        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
294    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
295        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
297    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
299    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
300        character were causing crashes (broken optimization).
302    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
303        \p or \P) caused a compile-time loop.
305    28. More problems have arisen in unanchored patterns when CRLF is a valid line
306        break. For example, the unstudied pattern [\r\n]A does not match the string
307        "\r\nA" because change 7.0/46 below moves the current point on by two
308        characters after failing to match at the start. However, the pattern \nA
309        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
310        the same is true. There doesn't seem any very clean way out of this, but
311        what I have chosen to do makes the common cases work: PCRE now takes note
312        of whether there can be an explicit match for \r or \n anywhere in the
313        pattern, and if so, 7.0/46 no longer applies. As part of this change,
314        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
315        pattern has explicit CR or LF references.
317    29. Added (*CR) etc for changing newline setting at start of pattern.
320    Version 7.2 19-Jun-07
321    ---------------------
323     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
324        which is apparently normally available under Windows.
326     2. Re-jig the pcregrep tests with different newline settings in an attempt
327        to make them independent of the local environment's newline setting.
329     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
331     4. Some of the "internals" tests were previously cut out when the link size
332        was not 2, because the output contained actual offsets. The recent new
333        "Z" feature of pcretest means that these can be cut out, making the tests
334        usable with all link sizes.
336     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
337        stack recursion. This gives a massive performance boost under BSD, but just
338        a small improvement under Linux. However, it saves one field in the frame
339        in all cases.
341     6. Added more features from the forthcoming Perl 5.10:
343        (a) (?-n) (where n is a string of digits) is a relative subroutine or
344            recursion call. It refers to the nth most recently opened parentheses.
346        (b) (?+n) is also a relative subroutine call; it refers to the nth next
347            to be opened parentheses.
349        (c) Conditions that refer to capturing parentheses can be specified
350            relatively, for example, (?(-2)... or (?(+3)...
352        (d) \K resets the start of the current match so that everything before
353            is not part of it.
355        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
357        (f) \g{name} is another synonym - part of Perl 5.10's unification of
358            reference syntax.
360        (g) (?| introduces a group in which the numbering of parentheses in each
361            alternative starts with the same number.
363        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
365     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
368     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
369        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
370        for detecting groups that can match an empty string.
372     9. A pattern with a very large number of alternatives (more than several
373        hundred) was running out of internal workspace during the pre-compile
374        phase, where pcre_compile() figures out how much memory will be needed. A
375        bit of new cunning has reduced the workspace needed for groups with
376        alternatives. The 1000-alternative test pattern now uses 12 bytes of
377        workspace instead of running out of the 4096 that are available.
379    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
381    11. Applied patch from Google to remove an optimization that didn't quite work.
382        The report of the bug said:
384          pcrecpp::RE("a*").FullMatch("aaa") matches, while
385          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
386          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
388    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
389        it matched the wrong number of bytes.
392    Version 7.1 24-Apr-07
393    ---------------------
395     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
396        that is more "standard", making use of automake and other Autotools. There
397        is some re-arrangement of the files and adjustment of comments consequent
398        on this.
400     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
401        for recursive directory scanning broke on some systems because the files
402        are not scanned in any specific order and on different systems the order
403        was different. A call to "sort" has been inserted into RunGrepTest for the
404        approprate test as a short-term fix. In the longer term there may be an
405        alternative.
407     3. I had an email from Eric Raymond about problems translating some of PCRE's
408        man pages to HTML (despite the fact that I distribute HTML pages, some
409        people do their own conversions for various reasons). The problems
410        concerned the use of low-level troff macros .br and .in. I have therefore
411        removed all such uses from the man pages (some were redundant, some could
412        be replaced by .nf/.fi pairs). The 132html script that I use to generate
413        HTML has been updated to handle .nf/.fi and to complain if it encounters
414        .br or .in.
416     4. Updated comments in configure.ac that get placed in config.h.in and also
417        arranged for config.h to be included in the distribution, with the name
418        config.h.generic, for the benefit of those who have to compile without
419        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
421     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
422        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
423        makevp.bat for the current PCRE, using the additional files
424        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
426     6. A Windows user reported a minor discrepancy with test 2, which turned out
427        to be caused by a trailing space on an input line that had got lost in his
428        copy. The trailing space was an accident, so I've just removed it.
430     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
431        that is needed.
433     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
434        as "const" (a) because they are and (b) because it helps the PHP
435        maintainers who have recently made a script to detect big data structures
436        in the php code that should be moved to the .rodata section. I remembered
437        to update Builducptable as well, so it won't revert if ucptable.h is ever
438        re-created.
440     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
441        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
442        order to be able to cut out the UTF-8 tables in the latter when UTF-8
443        support is not required. This saves 1.5-2K of code, which is important in
444        some applications.
446        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
447        so as not to refer to the tables, even though these functions will never be
448        called when UTF-8 support is disabled. Otherwise there are problems with a
449        shared library.
451    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
453        (a) It was defining its arguments as char * instead of void *.
455        (b) It was assuming that all moves were upwards in memory; this was true
456            a long time ago when I wrote it, but is no longer the case.
458        The emulated memove() is provided for those environments that have neither
459        memmove() nor bcopy(). I didn't think anyone used it these days, but that
460        is clearly not the case, as these two bugs were recently reported.
462    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
463        and Detrail to create the HTML documentation, the .txt form of the man
464        pages, and it removes trailing spaces from listed files. It also creates
465        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
466        case, it wraps all the #defines with #ifndefs. This script should be run
467        before "make dist".
469    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
470        with Unicode property support.
472        (a) For a maximizing quantifier, if the two different cases of the
473            character were of different lengths in their UTF-8 codings (there are
474            some cases like this - I found 11), and the matching function had to
475            back up over a mixture of the two cases, it incorrectly assumed they
476            were both the same length.
478        (b) When PCRE was configured to use the heap rather than the stack for
479            recursion during matching, it was not correctly preserving the data for
480            the other case of a UTF-8 character when checking ahead for a match
481            while processing a minimizing repeat. If the check also involved
482            matching a wide character, but failed, corruption could cause an
483            erroneous result when trying to check for a repeat of the original
484            character.
486    13. Some tidying changes to the testing mechanism:
488        (a) The RunTest script now detects the internal link size and whether there
489            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
490            values substituted by "configure". (The RunGrepTest script already did
491            this for UTF-8.) The configure.ac script no longer substitutes the
492            relevant variables.
494        (b) The debugging options /B and /D in pcretest show the compiled bytecode
495            with length and offset values. This means that the output is different
496            for different internal link sizes. Test 2 is skipped for link sizes
497            other than 2 because of this, bypassing the problem. Unfortunately,
498            there was also a test in test 3 (the locale tests) that used /B and
499            failed for link sizes other than 2. Rather than cut the whole test out,
500            I have added a new /Z option to pcretest that replaces the length and
501            offset values with spaces. This is now used to make test 3 independent
502            of link size. (Test 2 will be tidied up later.)
504    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
505        segmentation fault instead of returning the appropriate error message.
507    15. In multiline mode when the newline sequence was set to "any", the pattern
508        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
509        This doesn't seem right; it now treats the CRLF combination as the line
510        ending, and so does not match in that case. It's only a pattern such as ^$
511        that would hit this one: something like ^ABC$ would have failed after \r
512        and then tried again after \r\n.
514    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
515        in an attempt to make files that differ only in their line terminators
516        compare equal. This works on Linux.
518    17. Under certain error circumstances pcregrep might try to free random memory
519        as it exited. This is now fixed, thanks to valgrind.
521    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
522        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
523        was because its rules for how to advance for /g after matching an empty
524        string at the end of a line did not allow for this case. They now check for
525        it specially.
527    20. pcretest is supposed to handle patterns and data of any length, by
528        extending its buffers when necessary. It was getting this wrong when the
529        buffer for a data line had to be extended.
531    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
532        CRLF as a newline sequence.
534    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
535        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
536        I have nevertheless tidied it up.
538    23. Added some casts to kill warnings from HP-UX ia64 compiler.
540    24. Added a man page for pcre-config.
543    Version 7.0 19-Dec-06
544    ---------------------
546     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
547        moving to gcc 4.1.1.
549     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
550        sys/time.h, which is documented as needed for this function. It doesn't
551        seem to matter on Linux, but it showed up on some releases of OS X.
553     3. It seems that there are systems where bytes whose values are greater than
554        127 match isprint() in the "C" locale. The "C" locale should be the
555        default when a C program starts up. In most systems, only ASCII printing
556        characters match isprint(). This difference caused the output from pcretest
557        to vary, making some of the tests fail. I have changed pcretest so that:
559        (a) When it is outputting text in the compiled version of a pattern, bytes
560            other than 32-126 are always shown as hex escapes.
562        (b) When it is outputting text that is a matched part of a subject string,
563            it does the same, unless a different locale has been set for the match
564            (using the /L modifier). In this case, it uses isprint() to decide.
566     4. Fixed a major bug that caused incorrect computation of the amount of memory
567        required for a compiled pattern when options that changed within the
568        pattern affected the logic of the preliminary scan that determines the
569        length. The relevant options are -x, and -i in UTF-8 mode. The result was
570        that the computed length was too small. The symptoms of this bug were
571        either the PCRE error "internal error: code overflow" from pcre_compile(),
572        or a glibc crash with a message such as "pcretest: free(): invalid next
573        size (fast)". Examples of patterns that provoked this bug (shown in
574        pcretest format) are:
576          /(?-x: )/x
577          /(?x)(?-x: \s*#\s*)/
578          /((?i)[\x{c0}])/8
579          /(?i:[\x{c0}])/8
581        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
582        is now done differently.
584     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
585        wrapper classes; (b) implement a new function in the C++ scanner that is
586        more efficient than the old way of doing things because it avoids levels of
587        recursion in the regex matching; (c) add a paragraph to the documentation
588        for the FullMatch() function.
590     6. The escape sequence \n was being treated as whatever was defined as
591        "newline". Not only was this contrary to the documentation, which states
592        that \n is character 10 (hex 0A), but it also went horribly wrong when
593        "newline" was defined as CRLF. This has been fixed.
595     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
596        was being set to -1 for the "end of line" case (supposedly a value that no
597        character can have). Though this value is never used (the check for end of
598        line is "zero bytes in current character"), it caused compiler complaints.
599        I've changed it to 0xffffffff.
601     8. In pcre_version.c, the version string was being built by a sequence of
602        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
603        string (as it is for production releases) called a macro with an empty
604        argument. The C standard says the result of this is undefined. The gcc
605        compiler treats it as an empty string (which was what was wanted) but it is
606        reported that Visual C gives an error. The source has been hacked around to
607        avoid this problem.
609     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
610        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
611        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
612        of them did).
614    10. Originally, pcretest opened its input and output without "b"; then I was
615        told that "b" was needed in some environments, so it was added for release
616        5.0 to both the input and output. (It makes no difference on Unix-like
617        systems.) Later I was told that it is wrong for the input on Windows. I've
618        now abstracted the modes into two macros, to make it easier to fiddle with
619        them, and removed "b" from the input mode under Windows.
621    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
623    12. Added -help and --help to pcretest as an official way of being reminded
624        of the options.
626    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
627        and pcrecpp.cc because they annoy compilers at high warning levels.
629    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
631    15. Fixed an occurrence of == in configure.ac that should have been = (shell
632        scripts are not C programs :-) and which was not noticed because it works
633        on Linux.
635    16. pcretest is supposed to handle any length of pattern and data line (as one
636        line or as a continued sequence of lines) by extending its input buffer if
637        necessary. This feature was broken for very long pattern lines, leading to
638        a string of junk being passed to pcre_compile() if the pattern was longer
639        than about 50K.
641    17. I have done a major re-factoring of the way pcre_compile() computes the
642        amount of memory needed for a compiled pattern. Previously, there was code
643        that made a preliminary scan of the pattern in order to do this. That was
644        OK when PCRE was new, but as the facilities have expanded, it has become
645        harder and harder to keep it in step with the real compile phase, and there
646        have been a number of bugs (see for example, 4 above). I have now found a
647        cunning way of running the real compile function in a "fake" mode that
648        enables it to compute how much memory it would need, while actually only
649        ever using a few hundred bytes of working memory and without too many
650        tests of the mode. This should make future maintenance and development
651        easier. A side effect of this work is that the limit of 200 on the nesting
652        depth of parentheses has been removed (though this was never a serious
653        limitation, I suspect). However, there is a downside: pcre_compile() now
654        runs more slowly than before (30% or more, depending on the pattern). I
655        hope this isn't a big issue. There is no effect on runtime performance.
657    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
658        newline (only possible for the last line of a file) and it was a
659        pattern that set a locale (followed by /Lsomething), pcretest crashed.
661    19. Added additional timing features to pcretest. (1) The -tm option now times
662        matching only, not compiling. (2) Both -t and -tm can be followed, as a
663        separate command line item, by a number that specifies the number of
664        repeats to use when timing. The default is 50000; this gives better
665        precision, but takes uncomfortably long for very large patterns.
667    20. Extended pcre_study() to be more clever in cases where a branch of a
668        subpattern has no definite first character. For example, (a*|b*)[cd] would
669        previously give no result from pcre_study(). Now it recognizes that the
670        first character must be a, b, c, or d.
672    21. There was an incorrect error "recursive call could loop indefinitely" if
673        a subpattern (or the entire pattern) that was being tested for matching an
674        empty string contained only one non-empty item after a nested subpattern.
675        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
676        incorrectly, because the \d was being skipped in the check.
678    22. The pcretest program now has a new pattern option /B and a command line
679        option -b, which is equivalent to adding /B to every pattern. This causes
680        it to show the compiled bytecode, without the additional information that
681        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
682        is the same as /B/I).
684    23. A new optimization is now able automatically to treat some sequences such
685        as a*b as a*+b. More specifically, if something simple (such as a character
686        or a simple class like \d) has an unlimited quantifier, and is followed by
687        something that cannot possibly match the quantified thing, the quantifier
688        is automatically "possessified".
690    24. A recursive reference to a subpattern whose number was greater than 39
691        went wrong under certain circumstances in UTF-8 mode. This bug could also
692        have affected the operation of pcre_study().
694    25. Realized that a little bit of performance could be had by replacing
695        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
697    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
699    27. Possessive quantifiers such as a++ were previously implemented by turning
700        them into atomic groups such as ($>a+). Now they have their own opcodes,
701        which improves performance. This includes the automatically created ones
702        from 23 above.
704    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
705        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
706        the first matched character to be a colon. This applied both to named and
707        numbered groups.
709    29. The ucpinternal.h header file was missing its idempotency #ifdef.
711    30. I was sent a "project" file called libpcre.a.dev which I understand makes
712        building PCRE on Windows easier, so I have included it in the distribution.
714    31. There is now a check in pcretest against a ridiculously large number being
715        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
716        loop, the loop is abandoned.
718    32. Forward references to subpatterns in conditions such as (?(2)...) where
719        subpattern 2 is defined later cause pcre_compile() to search forwards in
720        the pattern for the relevant set of parentheses. This search went wrong
721        when there were unescaped parentheses in a character class, parentheses
722        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
724    33. "Subroutine" calls and backreferences were previously restricted to
725        referencing subpatterns earlier in the regex. This restriction has now
726        been removed.
728    34. Added a number of extra features that are going to be in Perl 5.10. On the
729        whole, these are just syntactic alternatives for features that PCRE had
730        previously implemented using the Python syntax or my own invention. The
731        other formats are all retained for compatibility.
733        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
734            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
735            also .NET compatible.
737        (b) A recursion or subroutine call to a named group can now be defined as
738            (?&name) as well as (?P>name).
740        (c) A backreference to a named group can now be defined as \k<name> or
741            \k'name' as well as (?P=name). The new forms, as well as being in Perl
742            5.10, are also .NET compatible.
744        (d) A conditional reference to a named group can now use the syntax
745            (?(<name>) or (?('name') as well as (?(name).
747        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
748            groups (named and numbered) that are never evaluated inline, but can be
749            called as "subroutines" from elsewhere. In effect, the DEFINE condition
750            is always false. There may be only one alternative in such a group.
752        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
753            as the simple (?(R). The condition is true only if the most recent
754            recursion is that of the given number or name. It does not search out
755            through the entire recursion stack.
757        (g) The escape \gN or \g{N} has been added, where N is a positive or
758            negative number, specifying an absolute or relative reference.
760    35. Tidied to get rid of some further signed/unsigned compiler warnings and
761        some "unreachable code" warnings.
763    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
764        things, this adds five new scripts.
766    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
767        There were also incompatibilities regarding the handling of \Q..\E inside
768        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
769        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
771    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
772        matches an empty string, and forcibly breaks the loop. There were bugs in
773        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
774        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
775        separate and independent bugs (that affected different cases) have been
776        fixed.
778    39. Refactored the code to abolish the use of different opcodes for small
779        capturing bracket numbers. This is a tidy that I avoided doing when I
780        removed the limit on the number of capturing brackets for 3.5 back in 2001.
781        The new approach is not only tidier, it makes it possible to reduce the
782        memory needed to fix the previous bug (38).
784    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
785        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
786        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
787        mode.
789    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
790        report.
792    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
793        copy construction and assignment in the C++ wrapper.
795    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
796        couple of bugs that could have given wrong results in the "--newline=crlf"
797        case.
799    44. Added a number of casts and did some reorganization of signed/unsigned int
800        variables following suggestions from Dair Grant. Also renamed the variable
801        "this" as "item" because it is a C++ keyword.
803    45. Arranged for dftables to add
805          #include "pcre_internal.h"
807        to pcre_chartables.c because without it, gcc 4.x may remove the array
808        definition from the final binary if PCRE is built into a static library and
809        dead code stripping is activated.
811    46. For an unanchored pattern, if a match attempt fails at the start of a
812        newline sequence, and the newline setting is CRLF or ANY, and the next two
813        characters are CRLF, advance by two characters instead of one.
816    Version 6.7 04-Jul-06
817    ---------------------
819     1. In order to handle tests when input lines are enormously long, pcretest has
820        been re-factored so that it automatically extends its buffers when
821        necessary. The code is crude, but this _is_ just a test program. The
822        default size has been increased from 32K to 50K.
824     2. The code in pcre_study() was using the value of the re argument before
825        testing it for NULL. (Of course, in any sensible call of the function, it
826        won't be NULL.)
828     3. The memmove() emulation function in pcre_internal.h, which is used on
829        systems that lack both memmove() and bcopy() - that is, hardly ever -
830        was missing a "static" storage class specifier.
832     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
833        containing an extended class (one that cannot be represented by a bitmap
834        because it contains high-valued characters or Unicode property items, e.g.
835        [\pZ]). Almost always one would set UTF-8 mode when processing such a
836        pattern, but PCRE should not loop if you do not (it no longer does).
837        [Detail: two cases were found: (a) a repeated subpattern containing an
838        extended class; (b) a recursive reference to a subpattern that followed a
839        previous extended class. It wasn't skipping over the extended class
840        correctly when UTF-8 mode was not set.]
842     5. A negated single-character class was not being recognized as fixed-length
843        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
844        compile error "lookbehind assertion is not fixed length".
846     6. The RunPerlTest auxiliary script was showing an unexpected difference
847        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
848        write a Perl script that can interpret lines of an input file either as
849        byte characters or as UTF-8, which is what "perltest" was being required to
850        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
851        can't do is switch easily at run time between having the "use utf8;" pragma
852        or not. In the end, I fudged it by using the RunPerlTest script to insert
853        "use utf8;" explicitly for the UTF-8 tests.
855     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
856        the end of the subject string, contrary to the documentation and to what
857        Perl does. This was true of both matching functions. Now it matches only at
858        the start of the subject and immediately after *internal* newlines.
860     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
861        a pointer to an int instead of a pointer to an unsigned long int. This
862        caused problems on 64-bit systems.
864     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
865        instance of the 'standard' template library not being so standard".
867    10. There was no check on the number of named subpatterns nor the maximum
868        length of a subpattern name. The product of these values is used to compute
869        the size of the memory block for a compiled pattern. By supplying a very
870        long subpattern name and a large number of named subpatterns, the size
871        computation could be caused to overflow. This is now prevented by limiting
872        the length of names to 32 characters, and the number of named subpatterns
873        to 10,000.
875    11. Subpatterns that are repeated with specific counts have to be replicated in
876        the compiled pattern. The size of memory for this was computed from the
877        length of the subpattern and the repeat count. The latter is limited to
878        65535, but there was no limit on the former, meaning that integer overflow
879        could in principle occur. The compiled length of a repeated subpattern is
880        now limited to 30,000 bytes in order to prevent this.
882    12. Added the optional facility to have named substrings with the same name.
884    13. Added the ability to use a named substring as a condition, using the
885        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
886        are numbers (not recommended). Forward references are permitted.
888    14. Added forward references in named backreferences (if you see what I mean).
890    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
891        pattern could run off the end of the subject. For example, the pattern
892        "(?s)(.{1,5})"8 did this with the subject "ab".
894    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
895        PCRE_CASELESS was set when matching characters that were quantified with ?
896        or *.
898    17. A character class other than a single negated character that had a minimum
899        but no maximum quantifier - for example [ab]{6,} - was not handled
900        correctly by pce_dfa_exec(). It would match only one character.
902    18. A valid (though odd) pattern that looked like a POSIX character
903        class but used an invalid character after [ (for example [[,abc,]]) caused
904        pcre_compile() to give the error "Failed: internal error: code overflow" or
905        in some cases to crash with a glibc free() error. This could even happen if
906        the pattern terminated after [[ but there just happened to be a sequence of
907        letters, a binary zero, and a closing ] in the memory that followed.
909    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
910        over the years. Originally (before any Unicode support), just the bottom 8
911        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
912        output from "man perlunicode" includes this:
914          The regular expression compiler produces polymorphic opcodes.  That
915          is, the pattern adapts to the data and automatically switches to
916          the Unicode character scheme when presented with Unicode data--or
917          instead uses a traditional byte scheme when presented with byte
918          data.
920        Sadly, a wide octal escape does not cause a switch, and in a string with
921        no other multibyte characters, these octal escapes are treated as before.
922        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
923        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
924        Unicode string.
926        I have not perpetrated such confusion in PCRE. Up till now, it took just
927        the bottom 8 bits, as in old Perl. I have now made octal escapes with
928        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
929        translate to the appropriate multibyte character.
931    29. Applied some refactoring to reduce the number of warnings from Microsoft
932        and Borland compilers. This has included removing the fudge introduced
933        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
934        a warning about an unused variable.
936    21. PCRE has not included VT (character 0x0b) in the set of whitespace
937        characters since release 4.0, because Perl (from release 5.004) does not.
938        [Or at least, is documented not to: some releases seem to be in conflict
939        with the documentation.] However, when a pattern was studied with
940        pcre_study() and all its branches started with \s, PCRE still included VT
941        as a possible starting character. Of course, this did no harm; it just
942        caused an unnecessary match attempt.
944    22. Removed a now-redundant internal flag bit that recorded the fact that case
945        dependency changed within the pattern. This was once needed for "required
946        byte" processing, but is no longer used. This recovers a now-scarce options
947        bit. Also moved the least significant internal flag bit to the most-
948        significant bit of the word, which was not previously used (hangover from
949        the days when it was an int rather than a uint) to free up another bit for
950        the future.
952    23. Added support for CRLF line endings as well as CR and LF. As well as the
953        default being selectable at build time, it can now be changed at runtime
954        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
955        specify that it is scanning data with non-default line endings.
957    24. Changed the definition of CXXLINK to make it agree with the definition of
958        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
960    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
961        recursions. This makes a big different to stack usage for some patterns.
963    26. If a subpattern containing a named recursion or subroutine reference such
964        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
965        the space required for the compiled pattern went wrong and gave too small a
966        value. Depending on the environment, this could lead to "Failed: internal
967        error: code overflow at offset 49" or "glibc detected double free or
968        corruption" errors.
970    27. Applied patches from Google (a) to support the new newline modes and (b) to
971        advance over multibyte UTF-8 characters in GlobalReplace.
973    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
974        difference for some implementation of PCRE in some Windows version.
976    29. Added some extra testing facilities to pcretest:
978        \q<number>   in a data line sets the "match limit" value
979        \Q<number>   in a data line sets the "match recursion limt" value
980        -S <number>  sets the stack size, where <number> is in megabytes
982        The -S option isn't available for Windows.
985    Version 6.6 06-Feb-06
986    ---------------------
988     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
989        in pcreposix.h. I have copied the definition from pcre.h.
991     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
992        because pcre.h is no longer a built file.
994     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
995        not normally included in the compiled code.
998    Version 6.5 01-Feb-06
999    ---------------------
1001     1. When using the partial match feature with pcre_dfa_exec(), it was not
1002        anchoring the second and subsequent partial matches at the new starting
1003        point. This could lead to incorrect results. For example, with the pattern
1004        /1234/, partially matching against "123" and then "a4" gave a match.
1006     2. Changes to pcregrep:
1008        (a) All non-match returns from pcre_exec() were being treated as failures
1009            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1010            error message is output. Some extra information is given for the
1011            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1012            probably the only errors that are likely to be caused by users (by
1013            specifying a regex that has nested indefinite repeats, for instance).
1014            If there are more than 20 of these errors, pcregrep is abandoned.
1016        (b) A binary zero was treated as data while matching, but terminated the
1017            output line if it was written out. This has been fixed: binary zeroes
1018            are now no different to any other data bytes.
1020        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1021            used to set a locale for matching. The --locale=xxxx long option has
1022            been added (no short equivalent) to specify a locale explicitly on the
1023            pcregrep command, overriding the environment variables.
1025        (d) When -B was used with -n, some line numbers in the output were one less
1026            than they should have been.
1028        (e) Added the -o (--only-matching) option.
1030        (f) If -A or -C was used with -c (count only), some lines of context were
1031            accidentally printed for the final match.
1033        (g) Added the -H (--with-filename) option.
1035        (h) The combination of options -rh failed to suppress file names for files
1036            that were found from directory arguments.
1038        (i) Added the -D (--devices) and -d (--directories) options.
1040        (j) Added the -F (--fixed-strings) option.
1042        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1044        (l) Added the --colo(u)r option.
1046        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1047            is not present by default.
1049     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1050        items such as (?R) or (?1), when the recursion could match a number of
1051        alternatives. If it matched one of the alternatives, but subsequently,
1052        outside the recursion, there was a failure, the code tried to back up into
1053        the recursion. However, because of the way PCRE is implemented, this is not
1054        possible, and the result was an incorrect result from the match.
1056        In order to prevent this happening, the specification of recursion has
1057        been changed so that all such subpatterns are automatically treated as
1058        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1060     4. I had overlooked the fact that, in some locales, there are characters for
1061        which isalpha() is true but neither isupper() nor islower() are true. In
1062        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1063        and ordfeminine) are like this. This affected the treatment of \w and \W
1064        when they appeared in character classes, but not when they appeared outside
1065        a character class. The bit map for "word" characters is now created
1066        separately from the results of isalnum() instead of just taking it from the
1067        upper, lower, and digit maps. (Plus the underscore character, of course.)
1069     5. The above bug also affected the handling of POSIX character classes such as
1070        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1071        permanent tables. Instead, the bit maps for such a class were previously
1072        created as the appropriate unions of the upper, lower, and digit bitmaps.
1073        Now they are created by subtraction from the [[:word:]] class, which has
1074        its own bitmap.
1076     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1077        It is created by subtracting the vertical space characters (\x09, \x0a,
1078        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1079        subtraction was done in the overall bitmap for a character class, meaning
1080        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1081        be recognized. This bug has been fixed.
1083     7. Patches from the folks at Google:
1085          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1086          real life, but is still worth protecting against".
1088          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1089          regular expressions".
1091          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1092          have it.
1094          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1095          "configure" and the latter not, in order to fix a problem somebody had
1096          with compiling the Arg class on HP-UX.
1098          (e) Improve the error-handling of the C++ wrapper a little bit.
1100          (f) New tests for checking recursion limiting.
1102     8. The pcre_memmove() function, which is used only if the environment does not
1103        have a standard memmove() function (and is therefore rarely compiled),
1104        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1105        returning a result (though PCRE never actually uses the result).
1107     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1108        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1109        returned instead of calling malloc() with an overflowing number that would
1110        most likely cause subsequent chaos.
1112    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1114    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1115        with this option is matched, the nmatch and pmatch options of regexec() are
1116        ignored.
1118    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1119        provided in case anyone wants to the the POSIX interface with UTF-8
1120        strings.
1122    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1123        C++ linking (needed for some HP-UX environments).
1125    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1126        (unused parameter) and in the pcre_printint() function (omitted "default"
1127        switch label when the default is to do nothing).
1129    15. Added some code to make it possible, when PCRE is compiled as a C++
1130        library, to replace subject pointers for pcre_exec() with a smart pointer
1131        class, thus making it possible to process discontinuous strings.
1133    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1134        much the same function. They were added by different people who were trying
1135        to make PCRE easy to compile on non-Unix systems. It has been suggested
1136        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1137        for compiling on Windows systems. I have therefore replaced it with
1138        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1139        defaults to "extern" for C or "extern C" for C++, which works fine on
1140        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1141        SCOPE with something explicit in config.h. In addition:
1143        (a) pcreposix.h still had just "extern" instead of either of these macros;
1144            I have replaced it with PCRE_DATA_SCOPE.
1146        (b) Functions such as _pcre_xclass(), which are internal to the library,
1147            but external in the C sense, all had PCRE_EXPORT in their definitions.
1148            This is apparently wrong for the Windows case, so I have removed it.
1149            (It makes no difference on Unix-like systems.)
1151    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1152        of recursive calls to match(). This is different to MATCH_LIMIT because
1153        that limits the total number of calls to match(), not all of which increase
1154        the depth of recursion. Limiting the recursion depth limits the amount of
1155        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1156        when PCRE is compiled, and changed at run time. A patch from Google adds
1157        this functionality to the C++ interface.
1159    18. Changes to the handling of Unicode character properties:
1161        (a) Updated the table to Unicode 4.1.0.
1163        (b) Recognize characters that are not in the table as "Cn" (undefined).
1165        (c) I revised the way the table is implemented to a much improved format
1166            which includes recognition of ranges. It now supports the ranges that
1167            are defined in UnicodeData.txt, and it also amalgamates other
1168            characters into ranges. This has reduced the number of entries in the
1169            table from around 16,000 to around 3,000, thus reducing its size
1170            considerably. I realized I did not need to use a tree structure after
1171            all - a binary chop search is just as efficient. Having reduced the
1172            number of entries, I extended their size from 6 bytes to 8 bytes to
1173            allow for more data.
1175        (d) Added support for Unicode script names via properties such as \p{Han}.
1177    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1178        matching that character.
1180    20. When matching a repeated Unicode property with a minimum greater than zero,
1181        (for example \pL{2,}), PCRE could look past the end of the subject if it
1182        reached it while seeking the minimum number of characters. This could
1183        happen only if some of the characters were more than one byte long, because
1184        there is a check for at least the minimum number of bytes.
1186    21. Refactored the implementation of \p and \P so as to be more general, to
1187        allow for more different types of property in future. This has changed the
1188        compiled form incompatibly. Anybody with saved compiled patterns that use
1189        \p or \P will have to recompile them.
1191    22. Added "Any" and "L&" to the supported property types.
1193    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1194        but give a compile time error if the value is greater than 0xff.
1196    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1197        accidentally not being installed or uninstalled.
1199    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1200        made were to insert the current release number. This seemed silly, because
1201        it made things harder for people building PCRE on systems that don't run
1202        "configure". I have turned pcre.h into a distributed file, no longer built
1203        by "configure", with the version identification directly included. There is
1204        no longer a pcre.h.in file.
1206        However, this change necessitated a change to the pcre-config script as
1207        well. It is built from pcre-config.in, and one of the substitutions was the
1208        release number. I have updated configure.ac so that ./configure now finds
1209        the release number by grepping pcre.h.
1211    26. Added the ability to run the tests under valgrind.
1214    Version 6.4 05-Sep-05
1215    ---------------------
1217     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1218        "--" to be printed when multiple files were scanned, even when none of the
1219        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1220        consider it to be a bug, and have restored the previous behaviour.
1222     2. A couple of code tidies to get rid of compiler warnings.
1224     3. The pcretest program used to cheat by referring to symbols in the library
1225        whose names begin with _pcre_. These are internal symbols that are not
1226        really supposed to be visible externally, and in some environments it is
1227        possible to suppress them. The cheating is now confined to including
1228        certain files from the library's source, which is a bit cleaner.
1230     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1231        file's purpose clearer.
1233     5. Reorganized pcre_ucp_findchar().
1236    Version 6.3 15-Aug-05
1237    ---------------------
1239     1. The file libpcre.pc.in did not have general read permission in the tarball.
1241     2. There were some problems when building without C++ support:
1243        (a) If C++ support was not built, "make install" and "make test" still
1244            tried to test it.
1246        (b) There were problems when the value of CXX was explicitly set. Some
1247            changes have been made to try to fix these, and ...
1249        (c) --disable-cpp can now be used to explicitly disable C++ support.
1251        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1252            backslash in a target when C++ was disabled. This confuses some
1253            versions of "make", apparently. Using an intermediate variable solves
1254            this. (Same for CPP_LOBJ.)
1256     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1257        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1258        necessary on certain architectures.
1260     4. Added a setting of -export-symbols-regex to the link command to remove
1261        those symbols that are exported in the C sense, but actually are local
1262        within the library, and not documented. Their names all begin with
1263        "_pcre_". This is not a perfect job, because (a) we have to except some
1264        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1265        available (and never for static libraries). I have made a note to try to
1266        find a way round (a) in the future.
1269    Version 6.2 01-Aug-05
1270    ---------------------
1272     1. There was no test for integer overflow of quantifier values. A construction
1273        such as {1111111111111111} would give undefined results. What is worse, if
1274        a minimum quantifier for a parenthesized subpattern overflowed and became
1275        negative, the calculation of the memory size went wrong. This could have
1276        led to memory overwriting.
1278     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1280     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1281        operating environments where this matters.
1283     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1284        PCRE options from within the C++ wrapper.
1286     5. Named capturing subpatterns were not being correctly counted when a pattern
1287        was compiled. This caused two problems: (a) If there were more than 100
1288        such subpatterns, the calculation of the memory needed for the whole
1289        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1290        back references of the form \12, where the number was greater than 9, were
1291        not recognized as back references, even though there were sufficient
1292        previous subpatterns.
1294     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1295        versions of gcc, e.g. 2.95.4.
1298    Version 6.1 21-Jun-05
1299    ---------------------
1301     1. There was one reference to the variable "posix" in pcretest.c that was not
1302        surrounded by "#if !defined NOPOSIX".
1304     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1305        the cross-check on the old pcre_info() function, for the benefit of the
1306        cut-down version of PCRE that is currently imported into Exim.
1308     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1309        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1310        patterns that start (?i) but I don't think that matters. The use of (?i) is
1311        just an example; this all applies to the other options as well.
1313     4. Since libtool seems to echo the compile commands it is issuing, the output
1314        from "make" can be reduced a bit by putting "@" in front of each libtool
1315        compile command.
1317     5. Patch from the folks at Google for configure.in to be a bit more thorough
1318        in checking for a suitable C++ installation before trying to compile the
1319        C++ stuff. This should fix a reported problem when a compiler was present,
1320        but no suitable headers.
1322     6. The man pages all had just "PCRE" as their title. I have changed them to
1323        be the relevant file name. I have also arranged that these names are
1324        retained in the file doc/pcre.txt, which is a concatenation in text format
1325        of all the man pages except the little individual ones for each function.
1327     7. The NON-UNIX-USE file had not been updated for the different set of source
1328        files that come with release 6. I also added a few comments about the C++
1329        wrapper.
1332    Version 6.0 07-Jun-05
1333    ---------------------
1335     1. Some minor internal re-organization to help with my DFA experiments.
1337     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1338        didn't matter for the library itself when fully configured, but did matter
1339        when compiling without UCP support, or within Exim, where the ucp files are
1340        not imported.
1342     3. Refactoring of the library code to split up the various functions into
1343        different source modules. The addition of the new DFA matching code (see
1344        below) to a single monolithic source would have made it really too
1345        unwieldy, quite apart from causing all the code to be include in a
1346        statically linked application, when only some functions are used. This is
1347        relevant even without the DFA addition now that patterns can be compiled in
1348        one application and matched in another.
1350        The downside of splitting up is that there have to be some external
1351        functions and data tables that are used internally in different modules of
1352        the library but which are not part of the API. These have all had their
1353        names changed to start with "_pcre_" so that they are unlikely to clash
1354        with other external names.
1356     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1357        a different (DFA) algorithm. Although it is slower than the original
1358        function, it does have some advantages for certain types of matching
1359        problem.
1361     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1362        including restarting after a partial match.
1364     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1365        defined when compiling for Windows was sent to me. I have put it into the
1366        code, though I have no means of testing or verifying it.
1368     7. Added the pcre_refcount() auxiliary function.
1370     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1371        match before or at the first newline in the subject string. In pcretest,
1372        the /f option on a pattern can be used to set this.
1374     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1375        would behave wrongly. This has been present in PCRE since release 4.0.
1377    10. A number of changes to the pcregrep command:
1379        (a) Refactored how -x works; insert ^(...)$ instead of setting
1380            PCRE_ANCHORED and checking the length, in preparation for adding
1381            something similar for -w.
1383        (b) Added the -w (match as a word) option.
1385        (c) Refactored the way lines are read and buffered so as to have more
1386            than one at a time available.
1388        (d) Implemented a pcregrep test script.
1390        (e) Added the -M (multiline match) option. This allows patterns to match
1391            over several lines of the subject. The buffering ensures that at least
1392            8K, or the rest of the document (whichever is the shorter) is available
1393            for matching (and similarly the previous 8K for lookbehind assertions).
1395        (f) Changed the --help output so that it now says
1397              -w, --word-regex(p)
1399            instead of two lines, one with "regex" and the other with "regexp"
1400            because that confused at least one person since the short forms are the
1401            same. (This required a bit of code, as the output is generated
1402            automatically from a table. It wasn't just a text change.)
1404        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1405            option but starts with a hyphen. Could be a pattern or a path name
1406            starting with a hyphen, for instance.
1408        (h) "-" can be given as a file name to represent stdin.
1410        (i) When file names are being printed, "(standard input)" is used for
1411            the standard input, for compatibility with GNU grep. Previously
1412            "<stdin>" was used.
1414        (j) The option --label=xxx can be used to supply a name to be used for
1415            stdin when file names are being printed. There is no short form.
1417        (k) Re-factored the options decoding logic because we are going to add
1418            two more options that take data. Such options can now be given in four
1419            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1421        (l) Added the -A, -B, and -C options for requesting that lines of context
1422            around matches be printed.
1424        (m) Added the -L option to print the names of files that do not contain
1425            any matching lines, that is, the complement of -l.
1427        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1428            continue to scan other files.
1430        (o) The -s option was incorrectly implemented. For compatibility with other
1431            greps, it now suppresses the error message for a non-existent or non-
1432            accessible file (but not the return code). There is a new option called
1433            -q that suppresses the output of matching lines, which was what -s was
1434            previously doing.
1436        (p) Added --include and --exclude options to specify files for inclusion
1437            and exclusion when recursing.
1439    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1440        Hopefully, it now does.
1442    12. Missing cast in pcre_study().
1444    13. Added an "uninstall" target to the makefile.
1446    14. Replaced "extern" in the function prototypes in Makefile.in with
1447        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1448        world, but is set differently for Windows.
1450    15. Added a second compiling function called pcre_compile2(). The only
1451        difference is that it has an extra argument, which is a pointer to an
1452        integer error code. When there is a compile-time failure, this is set
1453        non-zero, in addition to the error test pointer being set to point to an
1454        error message. The new argument may be NULL if no error number is required
1455        (but then you may as well call pcre_compile(), which is now just a
1456        wrapper). This facility is provided because some applications need a
1457        numeric error indication, but it has also enabled me to tidy up the way
1458        compile-time errors are handled in the POSIX wrapper.
1460    16. Added VPATH=.libs to the makefile; this should help when building with one
1461        prefix path and installing with another. (Or so I'm told by someone who
1462        knows more about this stuff than I do.)
1464    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1465        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1466        match everything, including newlines. This is not POSIX-compatible, but
1467        somebody wanted the feature. From pcretest it can be activated by using
1468        both the P and the s flags.
1470    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1472    19. libpcre.pc was being incorrectly installed as executable.
1474    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1475        it now also looks for '\r' so that it will work unmodified on Windows.
1477    21. Added Google's contributed C++ wrapper to the distribution.
1479    22. Added some untidy missing memory free() calls in pcretest, to keep
1480        Electric Fence happy when testing.
1484    Version 5.0 13-Sep-04
1485    ---------------------
1487     1. Internal change: literal characters are no longer packed up into items
1488        containing multiple characters in a single byte-string. Each character
1489        is now matched using a separate opcode. However, there may be more than one
1490        byte in the character in UTF-8 mode.
1492     2. The pcre_callout_block structure has two new fields: pattern_position and
1493        next_item_length. These contain the offset in the pattern to the next match
1494        item, and its length, respectively.
1496     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1497        insertion of callouts before each pattern item. Added the /C option to
1498        pcretest to make use of this.
1500     4. On the advice of a Windows user, the lines
1502          #if defined(_WIN32) || defined(WIN32)
1503          _setmode( _fileno( stdout ), 0x8000 );
1504          #endif  /* defined(_WIN32) || defined(WIN32) */
1506        have been added to the source of pcretest. This apparently does useful
1507        magic in relation to line terminators.
1509     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1510        for the benefit of those environments where the "b" makes a difference.
1512     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1513        to know about it. I have put a hack into configure.in that adds in code
1514        to set GCC=yes if CC=icc. This seems to end up at a point in the
1515        generated configure script that is early enough to affect the setting of
1516        compiler options, which is what is needed, but I have no means of testing
1517        whether it really works. (The user who reported this had patched the
1518        generated configure script, which of course I cannot do.)
1520        LATER: After change 22 below (new libtool files), the configure script
1521        seems to know about icc (and also ecc). Therefore, I have commented out
1522        this hack in configure.in.
1524     7. Added support for pkg-config (2 patches were sent in).
1526     8. Negated POSIX character classes that used a combination of internal tables
1527        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1528        [[:^ascii]]. Typically, they would match almost any characters. The other
1529        POSIX classes were not broken in this way.
1531     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1532        to find the match, as PCRE was deluded into thinking that the match had to
1533        start at the start point or following a newline. The same bug applied to
1534        patterns with negative forward assertions or any backward assertions
1535        preceding ".*" at the start, unless the pattern required a fixed first
1536        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1538    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1539        starting at the last subject character, bytes beyond the end of the subject
1540        string were read.
1542    11. Renamed the variable "class" as "classbits" to make life easier for C++
1543        users. (Previously there was a macro definition, but it apparently wasn't
1544        enough.)
1546    12. Added the new field "tables" to the extra data so that tables can be passed
1547        in at exec time, or the internal tables can be re-selected. This allows
1548        a compiled regex to be saved and re-used at a later time by a different
1549        program that might have everything at different addresses.
1551    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1552        -R library as well as a -L library.
1554    14. The debugging options of pcretest (-d on the command line or D on a
1555        pattern) showed incorrect output for anything following an extended class
1556        that contained multibyte characters and which was followed by a quantifier.
1558    15. Added optional support for general category Unicode character properties
1559        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1560        support. It adds about 90K to the size of the library. The meanings of the
1561        inbuilt class escapes such as \d and \s have NOT been changed.
1563    16. Updated pcredemo.c to include calls to free() to release the memory for the
1564        compiled pattern.
1566    17. The generated file chartables.c was being created in the source directory
1567        instead of in the building directory. This caused the build to fail if the
1568        source directory was different from the building directory, and was
1569        read-only.
1571    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1572        file. No doubt somebody will tell me if they don't make sense... Also added
1573        Dan Mooney's comments about building on OpenVMS.
1575    19. Added support for partial matching via the PCRE_PARTIAL option for
1576        pcre_exec() and the \P data escape in pcretest.
1578    20. Extended pcretest with 3 new pattern features:
1580        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1581              write the compiled pattern to the file whose name is "rest-of-line".
1582              This is a straight binary dump of the data, with the saved pointer to
1583              the character tables forced to be NULL. The study data, if any, is
1584              written too. After writing, pcretest reads a new pattern.
1586        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1587              compiled pattern from the given file. There must not be any
1588              occurrences of "<" in the file name (pretty unlikely); if there are,
1589              pcretest will instead treat the initial "<" as a pattern delimiter.
1590              After reading in the pattern, pcretest goes on to read data lines as
1591              usual.
1593        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1594              and 16-bit fields in a compiled pattern, to simulate a pattern that
1595              was compiled on a host of opposite endianness.
1597    21. The pcre-exec() function can now cope with patterns that were compiled on
1598        hosts of opposite endianness, with this restriction:
1600          As for any compiled expression that is saved and used later, the tables
1601          pointer field cannot be preserved; the extra_data field in the arguments
1602          to pcre_exec() should be used to pass in a tables address if a value
1603          other than the default internal tables were used at compile time.
1605    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1606        now diagnosed as an error. Previously, most of the time, a negative number
1607        would have been treated as zero, but if in addition "ovector" was passed as
1608        NULL, a crash could occur.
1610    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1611        new versions from the libtool 1.5 distribution (the last one is a copy of
1612        a file called libtool.m4). This seems to have fixed the need to patch
1613        "configure" to support Darwin 1.3 (which I used to do). However, I still
1614        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1615        workstation).
1617    24. Changed the PCRE licence to be the more standard "BSD" licence.
1620    Version 4.5 01-Dec-03
1621    ---------------------
1623     1. There has been some re-arrangement of the code for the match() function so
1624        that it can be compiled in a version that does not call itself recursively.
1625        Instead, it keeps those local variables that need separate instances for
1626        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1627        needs to "recurse". Keeping track of where control must go is done by means
1628        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1629        hide most of the details from the main code, and operates only if
1630        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1631        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1632        operating.
1634        To make it easier for callers to provide specially tailored get/free
1635        functions for this usage, two new functions, pcre_stack_malloc, and
1636        pcre_stack_free, are used. They are always called in strict stacking order,
1637        and the size of block requested is always the same.
1639        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1640        PCRE has been compiled to use the stack or the heap for recursion. The
1641        -C option of pcretest uses this to show which version is compiled.
1643        A new data escape \S, is added to pcretest; it causes the amounts of store
1644        obtained and freed by both kinds of malloc/free at match time to be added
1645        to the output.
1647     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1648        what's available on my current Linux desktop machine.
1650     3. When matching a UTF-8 string, the test for a valid string at the start has
1651        been extended. If start_offset is not zero, PCRE now checks that it points
1652        to a byte that is the start of a UTF-8 character. If not, it returns
1653        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1654        this is necessary because there may be backward assertions in the pattern.
1655        When matching the same subject several times, it may save resources to use
1656        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1658     4. The code for checking the validity of UTF-8 strings has been tightened so
1659        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1660        containing "overlong sequences".
1662     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1663        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1664        should have been "&", but it just so happened that all the cases this let
1665        through by mistake were picked up later in the function.
1667     6. I had used a variable called "isblank" - this is a C99 function, causing
1668        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1670     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1671        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1672        so the version is shown; (c) stop "make test" echoing "./RunTest".
1674     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1676     9. The prototype for memmove() for systems that don't have it was using
1677        size_t, but the inclusion of the header that defines size_t was later. I've
1678        moved the #includes for the C headers earlier to avoid this.
1680    10. Added some adjustments to the code to make it easier to compiler on certain
1681        special systems:
1683          (a) Some "const" qualifiers were missing.
1684          (b) Added the macro EXPORT before all exported functions; by default this
1685              is defined to be empty.
1686          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1687              that it reads its output file name as an argument instead of writing
1688              to the standard output and assuming this can be redirected.
1690    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1691        class containing characters with values greater than 255, PCRE compilation
1692        went into a loop.
1694    12. A recursive reference to a subpattern that was within another subpattern
1695        that had a minimum quantifier of zero caused PCRE to crash. For example,
1696        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1697        recursion. If the recursively-called subpattern itself had a zero repeat,
1698        that was OK.
1700    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1701        buffer into which it was copied (for escape processing) was still set at
1702        1024, so long lines caused crashes.
1704    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1705        "internal error: code overflow...". This applied to any character class
1706        that was followed by a possessive quantifier.
1708    15. Modified the Makefile to add libpcre.la as a prerequisite for
1709        libpcreposix.la because I was told this is needed for a parallel build to
1710        work.
1712    16. If a pattern that contained .* following optional items at the start was
1713        studied, the wrong optimizing data was generated, leading to matching
1714        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1715        matching string must start with a or b or c. The correct conclusion for
1716        this pattern is that a match can start with any character.
1719    Version 4.4 13-Aug-03
1720    ---------------------
1722     1. In UTF-8 mode, a character class containing characters with values between
1723        127 and 255 was not handled correctly if the compiled pattern was studied.
1724        In fixing this, I have also improved the studying algorithm for such
1725        classes (slightly).
1727     2. Three internal functions had redundant arguments passed to them. Removal
1728        might give a very teeny performance improvement.
1730     3. Documentation bug: the value of the capture_top field in a callout is *one
1731        more than* the number of the hightest numbered captured substring.
1733     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1734        in incorrectly linking with a previously installed version. They now link
1735        explicitly with libpcre.la.
1737     5. configure.in no longer needs to recognize Cygwin specially.
1739     6. A problem in pcre.in for Windows platforms is fixed.
1741     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1742        pcretest, it used to include the size of the study block as part of its
1743        output. Unfortunately, the structure contains a field that has a different
1744        size on different hardware architectures. This meant that the tests that
1745        showed this size failed. As the block is currently always of a fixed size,
1746        this information isn't actually particularly useful in pcretest output, so
1747        I have just removed it.
1749     8. Three pre-processor statements accidentally did not start in column 1.
1750        Sadly, there are *still* compilers around that complain, even though
1751        standard C has not required this for well over a decade. Sigh.
1753     9. In pcretest, the code for checking callouts passed small integers in the
1754        callout_data field, which is a void * field. However, some picky compilers
1755        complained about the casts involved for this on 64-bit systems. Now
1756        pcretest passes the address of the small integer instead, which should get
1757        rid of the warnings.
1759    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1760        both compile and run time, and gives an error if an invalid UTF-8 sequence
1761        is found. There is a option for disabling this check in cases where the
1762        string is known to be correct and/or the maximum performance is wanted.
1764    11. In response to a bug report, I changed one line in Makefile.in from
1766            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1767        to
1768            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1770        to look similar to other lines, but I have no way of telling whether this
1771        is the right thing to do, as I do not use Windows. No doubt I'll get told
1772        if it's wrong...
1775  Version 4.3 21-May-03  Version 4.3 21-May-03
1776  ---------------------  ---------------------

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