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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.4 10-Sep-07
5    ---------------------
7    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
8        means that a class such as [\s] counted as "explicit reference to CR or
9        LF". That isn't really right - the whole point of the change was to try to
10        help when there was an actual mention of one of the two characters. So now
11        the change happens only if \r or \n (or a literal CR or LF) character is
12        encountered.
14    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
15        of both had grown to the point where there were only 3 bits left.
16        Fortunately, there was spare space in the data structure, and so I have
17        moved the internal flags into a new 16-bit field to free up more option
18        bits.
20    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
21        but did not set the internal JCHANGED flag - either of these is enough to
22        control the way the "get" function works - but the PCRE_INFO_JCHANGED
23        facility is supposed to tell if (?J) was ever used, so now (?J) at the
24        start sets both bits.
26    4.  Added options (at build time, compile time, exec time) to change \R from
27        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
29    5.  doc/pcresyntax.html was missing from the distribution.
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
34    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
35        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
36        windows.h file is present (where different names are used).
38    8.  Changed all #include <config.h> to #include "config.h". There were also
39        some further <pcre.h> cases that I changed to "pcre.h".
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
44    10. It was pointed out to me that arrays of string pointers cause lots of
45        relocations when a shared library is dynamically loaded. A technique of
46        using a single long string with a table of offsets can drastically reduce
47        these. I have refactored PCRE in four places to do this. The result is
48        dramatic:
50          Originally:                          290
51          After changing UCP table:            187
52          After changing error message table:   43
53          After changing table of "verbs"       36
54          After changing table of Posix names   22
56        Thanks to the folks working on Gregex for glib for this insight.
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
61    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
63    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
64        checked only for CRLF.
67    Version 7.3 28-Aug-07
68    ---------------------
70     1. In the rejigging of the build system that eventually resulted in 7.1, the
71        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
72        brackets there is not right, since it causes compilers to look for an
73        installed pcre.h, not the version that is in the source that is being
74        compiled (which of course may be different). I have changed it back to:
76          #include "pcre.h"
78        I have a vague recollection that the change was concerned with compiling in
79        different directories, but in the new build system, that is taken care of
80        by the VPATH setting the Makefile.
82     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
83        when the subject happened to end in the byte 0x85 (e.g. if the last
84        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
85        characters but of course it shouldn't be taken as a newline when it is part
86        of another character. The bug was that, for an unlimited repeat of . in
87        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
88        characters when looking for a newline.
90     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
92     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
93        in debug output.
95     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
96        long printing in the pcrecpp unittest when running under MinGW.
98     6. ESC_K was left out of the EBCDIC table.
100     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
101        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
102        limit also applies to "virtual nesting" when a pattern is recursive, and in
103        this case 1000 isn't so big. I have been able to remove this limit at the
104        expense of backing off one optimization in certain circumstances. Normally,
105        when pcre_exec() would call its internal match() function recursively and
106        immediately return the result unconditionally, it uses a "tail recursion"
107        feature to save stack. However, when a subpattern that can match an empty
108        string has an unlimited repetition quantifier, it no longer makes this
109        optimization. That gives it a stack frame in which to save the data for
110        checking that an empty string has been matched. Previously this was taken
111        from the 1000-entry workspace that had been reserved. So now there is no
112        explicit limit, but more stack is used.
114     8. Applied Daniel's patches to solve problems with the import/export magic
115        syntax that is required for Windows, and which was going wrong for the
116        pcreposix and pcrecpp parts of the library. These were overlooked when this
117        problem was solved for the main library.
119     9. There were some crude static tests to avoid integer overflow when computing
120        the size of patterns that contain repeated groups with explicit upper
121        limits. As the maximum quantifier is 65535, the maximum group length was
122        set at 30,000 so that the product of these two numbers did not overflow a
123        32-bit integer. However, it turns out that people want to use groups that
124        are longer than 30,000 bytes (though not repeat them that many times).
125        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
126        made it possible to implement the integer overflow checks in a much more
127        dynamic way, which I have now done. The artificial limitation on group
128        length has been removed - we now have only the limit on the total length of
129        the compiled pattern, which depends on the LINK_SIZE setting.
131    10. Fixed a bug in the documentation for get/copy named substring when
132        duplicate names are permitted. If none of the named substrings are set, the
133        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
134        empty string.
136    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
137        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
138        because the ] is interpreted as the first data character and the
139        terminating ] is not found. PCRE has been made compatible with Perl in this
140        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
141        cause memory overwriting.
143    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
144        string has been matched (to stop an infinite loop). It was not recognizing
145        a conditional subpattern that could match an empty string if that
146        subpattern was within another subpattern. For example, it looped when
147        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
148        condition was not nested. This bug has been fixed.
150    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
151        past the start of the subject in the presence of bytes with the top bit
152        set, for example "\x8aBCD".
154    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
155        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
157    14. Optimized (?!) to (*FAIL).
159    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
160        This restricts code points to be within the range 0 to 0x10FFFF, excluding
161        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
162        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
163        does: it's just the validity check that is more restrictive.
165    16. Inserted checks for integer overflows during escape sequence (backslash)
166        processing, and also fixed erroneous offset values for syntax errors during
167        backslash processing.
169    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
170        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
172    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
173        caused an overrun.
175    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
176        something other than just ASCII characters) inside a group that had an
177        unlimited repeat caused a loop at compile time (while checking to see
178        whether the group could match an empty string).
180    20. Debugging a pattern containing \p or \P could cause a crash. For example,
181        [\P{Any}] did so. (Error in the code for printing property names.)
183    21. An orphan \E inside a character class could cause a crash.
185    22. A repeated capturing bracket such as (A)? could cause a wild memory
186        reference during compilation.
188    23. There are several functions in pcre_compile() that scan along a compiled
189        expression for various reasons (e.g. to see if it's fixed length for look
190        behind). There were bugs in these functions when a repeated \p or \P was
191        present in the pattern. These operators have additional parameters compared
192        with \d, etc, and these were not being taken into account when moving along
193        the compiled data. Specifically:
195        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
196            length.
198        (b) An item such as \pL+ within a repeated group could cause crashes or
199            loops.
201        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
202            "reference to non-existent subpattern" error.
204        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
206    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
207        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
209    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
211    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
212        character were causing crashes (broken optimization).
214    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
215        \p or \P) caused a compile-time loop.
217    28. More problems have arisen in unanchored patterns when CRLF is a valid line
218        break. For example, the unstudied pattern [\r\n]A does not match the string
219        "\r\nA" because change 7.0/46 below moves the current point on by two
220        characters after failing to match at the start. However, the pattern \nA
221        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
222        the same is true. There doesn't seem any very clean way out of this, but
223        what I have chosen to do makes the common cases work: PCRE now takes note
224        of whether there can be an explicit match for \r or \n anywhere in the
225        pattern, and if so, 7.0/46 no longer applies. As part of this change,
226        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
227        pattern has explicit CR or LF references.
229    29. Added (*CR) etc for changing newline setting at start of pattern.
232    Version 7.2 19-Jun-07
233    ---------------------
235     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
236        which is apparently normally available under Windows.
238     2. Re-jig the pcregrep tests with different newline settings in an attempt
239        to make them independent of the local environment's newline setting.
241     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
243     4. Some of the "internals" tests were previously cut out when the link size
244        was not 2, because the output contained actual offsets. The recent new
245        "Z" feature of pcretest means that these can be cut out, making the tests
246        usable with all link sizes.
248     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
249        stack recursion. This gives a massive performance boost under BSD, but just
250        a small improvement under Linux. However, it saves one field in the frame
251        in all cases.
253     6. Added more features from the forthcoming Perl 5.10:
255        (a) (?-n) (where n is a string of digits) is a relative subroutine or
256            recursion call. It refers to the nth most recently opened parentheses.
258        (b) (?+n) is also a relative subroutine call; it refers to the nth next
259            to be opened parentheses.
261        (c) Conditions that refer to capturing parentheses can be specified
262            relatively, for example, (?(-2)... or (?(+3)...
264        (d) \K resets the start of the current match so that everything before
265            is not part of it.
267        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
269        (f) \g{name} is another synonym - part of Perl 5.10's unification of
270            reference syntax.
272        (g) (?| introduces a group in which the numbering of parentheses in each
273            alternative starts with the same number.
275        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
277     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
280     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
281        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
282        for detecting groups that can match an empty string.
284     9. A pattern with a very large number of alternatives (more than several
285        hundred) was running out of internal workspace during the pre-compile
286        phase, where pcre_compile() figures out how much memory will be needed. A
287        bit of new cunning has reduced the workspace needed for groups with
288        alternatives. The 1000-alternative test pattern now uses 12 bytes of
289        workspace instead of running out of the 4096 that are available.
291    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
293    11. Applied patch from Google to remove an optimization that didn't quite work.
294        The report of the bug said:
296          pcrecpp::RE("a*").FullMatch("aaa") matches, while
297          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
298          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
300    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
301        it matched the wrong number of bytes.
304    Version 7.1 24-Apr-07
305    ---------------------
307     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
308        that is more "standard", making use of automake and other Autotools. There
309        is some re-arrangement of the files and adjustment of comments consequent
310        on this.
312     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
313        for recursive directory scanning broke on some systems because the files
314        are not scanned in any specific order and on different systems the order
315        was different. A call to "sort" has been inserted into RunGrepTest for the
316        approprate test as a short-term fix. In the longer term there may be an
317        alternative.
319     3. I had an email from Eric Raymond about problems translating some of PCRE's
320        man pages to HTML (despite the fact that I distribute HTML pages, some
321        people do their own conversions for various reasons). The problems
322        concerned the use of low-level troff macros .br and .in. I have therefore
323        removed all such uses from the man pages (some were redundant, some could
324        be replaced by .nf/.fi pairs). The 132html script that I use to generate
325        HTML has been updated to handle .nf/.fi and to complain if it encounters
326        .br or .in.
328     4. Updated comments in configure.ac that get placed in config.h.in and also
329        arranged for config.h to be included in the distribution, with the name
330        config.h.generic, for the benefit of those who have to compile without
331        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
333     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
334        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
335        makevp.bat for the current PCRE, using the additional files
336        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
338     6. A Windows user reported a minor discrepancy with test 2, which turned out
339        to be caused by a trailing space on an input line that had got lost in his
340        copy. The trailing space was an accident, so I've just removed it.
342     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
343        that is needed.
345     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
346        as "const" (a) because they are and (b) because it helps the PHP
347        maintainers who have recently made a script to detect big data structures
348        in the php code that should be moved to the .rodata section. I remembered
349        to update Builducptable as well, so it won't revert if ucptable.h is ever
350        re-created.
352     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
353        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
354        order to be able to cut out the UTF-8 tables in the latter when UTF-8
355        support is not required. This saves 1.5-2K of code, which is important in
356        some applications.
358        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
359        so as not to refer to the tables, even though these functions will never be
360        called when UTF-8 support is disabled. Otherwise there are problems with a
361        shared library.
363    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
365        (a) It was defining its arguments as char * instead of void *.
367        (b) It was assuming that all moves were upwards in memory; this was true
368            a long time ago when I wrote it, but is no longer the case.
370        The emulated memove() is provided for those environments that have neither
371        memmove() nor bcopy(). I didn't think anyone used it these days, but that
372        is clearly not the case, as these two bugs were recently reported.
374    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
375        and Detrail to create the HTML documentation, the .txt form of the man
376        pages, and it removes trailing spaces from listed files. It also creates
377        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
378        case, it wraps all the #defines with #ifndefs. This script should be run
379        before "make dist".
381    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
382        with Unicode property support.
384        (a) For a maximizing quantifier, if the two different cases of the
385            character were of different lengths in their UTF-8 codings (there are
386            some cases like this - I found 11), and the matching function had to
387            back up over a mixture of the two cases, it incorrectly assumed they
388            were both the same length.
390        (b) When PCRE was configured to use the heap rather than the stack for
391            recursion during matching, it was not correctly preserving the data for
392            the other case of a UTF-8 character when checking ahead for a match
393            while processing a minimizing repeat. If the check also involved
394            matching a wide character, but failed, corruption could cause an
395            erroneous result when trying to check for a repeat of the original
396            character.
398    13. Some tidying changes to the testing mechanism:
400        (a) The RunTest script now detects the internal link size and whether there
401            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
402            values substituted by "configure". (The RunGrepTest script already did
403            this for UTF-8.) The configure.ac script no longer substitutes the
404            relevant variables.
406        (b) The debugging options /B and /D in pcretest show the compiled bytecode
407            with length and offset values. This means that the output is different
408            for different internal link sizes. Test 2 is skipped for link sizes
409            other than 2 because of this, bypassing the problem. Unfortunately,
410            there was also a test in test 3 (the locale tests) that used /B and
411            failed for link sizes other than 2. Rather than cut the whole test out,
412            I have added a new /Z option to pcretest that replaces the length and
413            offset values with spaces. This is now used to make test 3 independent
414            of link size. (Test 2 will be tidied up later.)
416    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
417        segmentation fault instead of returning the appropriate error message.
419    15. In multiline mode when the newline sequence was set to "any", the pattern
420        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
421        This doesn't seem right; it now treats the CRLF combination as the line
422        ending, and so does not match in that case. It's only a pattern such as ^$
423        that would hit this one: something like ^ABC$ would have failed after \r
424        and then tried again after \r\n.
426    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
427        in an attempt to make files that differ only in their line terminators
428        compare equal. This works on Linux.
430    17. Under certain error circumstances pcregrep might try to free random memory
431        as it exited. This is now fixed, thanks to valgrind.
433    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
434        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
435        was because its rules for how to advance for /g after matching an empty
436        string at the end of a line did not allow for this case. They now check for
437        it specially.
439    20. pcretest is supposed to handle patterns and data of any length, by
440        extending its buffers when necessary. It was getting this wrong when the
441        buffer for a data line had to be extended.
443    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
444        CRLF as a newline sequence.
446    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
447        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
448        I have nevertheless tidied it up.
450    23. Added some casts to kill warnings from HP-UX ia64 compiler.
452    24. Added a man page for pcre-config.
455    Version 7.0 19-Dec-06
456    ---------------------
458     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
459        moving to gcc 4.1.1.
461     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
462        sys/time.h, which is documented as needed for this function. It doesn't
463        seem to matter on Linux, but it showed up on some releases of OS X.
465     3. It seems that there are systems where bytes whose values are greater than
466        127 match isprint() in the "C" locale. The "C" locale should be the
467        default when a C program starts up. In most systems, only ASCII printing
468        characters match isprint(). This difference caused the output from pcretest
469        to vary, making some of the tests fail. I have changed pcretest so that:
471        (a) When it is outputting text in the compiled version of a pattern, bytes
472            other than 32-126 are always shown as hex escapes.
474        (b) When it is outputting text that is a matched part of a subject string,
475            it does the same, unless a different locale has been set for the match
476            (using the /L modifier). In this case, it uses isprint() to decide.
478     4. Fixed a major bug that caused incorrect computation of the amount of memory
479        required for a compiled pattern when options that changed within the
480        pattern affected the logic of the preliminary scan that determines the
481        length. The relevant options are -x, and -i in UTF-8 mode. The result was
482        that the computed length was too small. The symptoms of this bug were
483        either the PCRE error "internal error: code overflow" from pcre_compile(),
484        or a glibc crash with a message such as "pcretest: free(): invalid next
485        size (fast)". Examples of patterns that provoked this bug (shown in
486        pcretest format) are:
488          /(?-x: )/x
489          /(?x)(?-x: \s*#\s*)/
490          /((?i)[\x{c0}])/8
491          /(?i:[\x{c0}])/8
493        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
494        is now done differently.
496     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
497        wrapper classes; (b) implement a new function in the C++ scanner that is
498        more efficient than the old way of doing things because it avoids levels of
499        recursion in the regex matching; (c) add a paragraph to the documentation
500        for the FullMatch() function.
502     6. The escape sequence \n was being treated as whatever was defined as
503        "newline". Not only was this contrary to the documentation, which states
504        that \n is character 10 (hex 0A), but it also went horribly wrong when
505        "newline" was defined as CRLF. This has been fixed.
507     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
508        was being set to -1 for the "end of line" case (supposedly a value that no
509        character can have). Though this value is never used (the check for end of
510        line is "zero bytes in current character"), it caused compiler complaints.
511        I've changed it to 0xffffffff.
513     8. In pcre_version.c, the version string was being built by a sequence of
514        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
515        string (as it is for production releases) called a macro with an empty
516        argument. The C standard says the result of this is undefined. The gcc
517        compiler treats it as an empty string (which was what was wanted) but it is
518        reported that Visual C gives an error. The source has been hacked around to
519        avoid this problem.
521     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
522        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
523        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
524        of them did).
526    10. Originally, pcretest opened its input and output without "b"; then I was
527        told that "b" was needed in some environments, so it was added for release
528        5.0 to both the input and output. (It makes no difference on Unix-like
529        systems.) Later I was told that it is wrong for the input on Windows. I've
530        now abstracted the modes into two macros, to make it easier to fiddle with
531        them, and removed "b" from the input mode under Windows.
533    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
535    12. Added -help and --help to pcretest as an official way of being reminded
536        of the options.
538    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
539        and pcrecpp.cc because they annoy compilers at high warning levels.
541    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
543    15. Fixed an occurrence of == in configure.ac that should have been = (shell
544        scripts are not C programs :-) and which was not noticed because it works
545        on Linux.
547    16. pcretest is supposed to handle any length of pattern and data line (as one
548        line or as a continued sequence of lines) by extending its input buffer if
549        necessary. This feature was broken for very long pattern lines, leading to
550        a string of junk being passed to pcre_compile() if the pattern was longer
551        than about 50K.
553    17. I have done a major re-factoring of the way pcre_compile() computes the
554        amount of memory needed for a compiled pattern. Previously, there was code
555        that made a preliminary scan of the pattern in order to do this. That was
556        OK when PCRE was new, but as the facilities have expanded, it has become
557        harder and harder to keep it in step with the real compile phase, and there
558        have been a number of bugs (see for example, 4 above). I have now found a
559        cunning way of running the real compile function in a "fake" mode that
560        enables it to compute how much memory it would need, while actually only
561        ever using a few hundred bytes of working memory and without too many
562        tests of the mode. This should make future maintenance and development
563        easier. A side effect of this work is that the limit of 200 on the nesting
564        depth of parentheses has been removed (though this was never a serious
565        limitation, I suspect). However, there is a downside: pcre_compile() now
566        runs more slowly than before (30% or more, depending on the pattern). I
567        hope this isn't a big issue. There is no effect on runtime performance.
569    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
570        newline (only possible for the last line of a file) and it was a
571        pattern that set a locale (followed by /Lsomething), pcretest crashed.
573    19. Added additional timing features to pcretest. (1) The -tm option now times
574        matching only, not compiling. (2) Both -t and -tm can be followed, as a
575        separate command line item, by a number that specifies the number of
576        repeats to use when timing. The default is 50000; this gives better
577        precision, but takes uncomfortably long for very large patterns.
579    20. Extended pcre_study() to be more clever in cases where a branch of a
580        subpattern has no definite first character. For example, (a*|b*)[cd] would
581        previously give no result from pcre_study(). Now it recognizes that the
582        first character must be a, b, c, or d.
584    21. There was an incorrect error "recursive call could loop indefinitely" if
585        a subpattern (or the entire pattern) that was being tested for matching an
586        empty string contained only one non-empty item after a nested subpattern.
587        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
588        incorrectly, because the \d was being skipped in the check.
590    22. The pcretest program now has a new pattern option /B and a command line
591        option -b, which is equivalent to adding /B to every pattern. This causes
592        it to show the compiled bytecode, without the additional information that
593        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
594        is the same as /B/I).
596    23. A new optimization is now able automatically to treat some sequences such
597        as a*b as a*+b. More specifically, if something simple (such as a character
598        or a simple class like \d) has an unlimited quantifier, and is followed by
599        something that cannot possibly match the quantified thing, the quantifier
600        is automatically "possessified".
602    24. A recursive reference to a subpattern whose number was greater than 39
603        went wrong under certain circumstances in UTF-8 mode. This bug could also
604        have affected the operation of pcre_study().
606    25. Realized that a little bit of performance could be had by replacing
607        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
609    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
611    27. Possessive quantifiers such as a++ were previously implemented by turning
612        them into atomic groups such as ($>a+). Now they have their own opcodes,
613        which improves performance. This includes the automatically created ones
614        from 23 above.
616    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
617        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
618        the first matched character to be a colon. This applied both to named and
619        numbered groups.
621    29. The ucpinternal.h header file was missing its idempotency #ifdef.
623    30. I was sent a "project" file called libpcre.a.dev which I understand makes
624        building PCRE on Windows easier, so I have included it in the distribution.
626    31. There is now a check in pcretest against a ridiculously large number being
627        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
628        loop, the loop is abandoned.
630    32. Forward references to subpatterns in conditions such as (?(2)...) where
631        subpattern 2 is defined later cause pcre_compile() to search forwards in
632        the pattern for the relevant set of parentheses. This search went wrong
633        when there were unescaped parentheses in a character class, parentheses
634        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
636    33. "Subroutine" calls and backreferences were previously restricted to
637        referencing subpatterns earlier in the regex. This restriction has now
638        been removed.
640    34. Added a number of extra features that are going to be in Perl 5.10. On the
641        whole, these are just syntactic alternatives for features that PCRE had
642        previously implemented using the Python syntax or my own invention. The
643        other formats are all retained for compatibility.
645        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
646            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
647            also .NET compatible.
649        (b) A recursion or subroutine call to a named group can now be defined as
650            (?&name) as well as (?P>name).
652        (c) A backreference to a named group can now be defined as \k<name> or
653            \k'name' as well as (?P=name). The new forms, as well as being in Perl
654            5.10, are also .NET compatible.
656        (d) A conditional reference to a named group can now use the syntax
657            (?(<name>) or (?('name') as well as (?(name).
659        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
660            groups (named and numbered) that are never evaluated inline, but can be
661            called as "subroutines" from elsewhere. In effect, the DEFINE condition
662            is always false. There may be only one alternative in such a group.
664        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
665            as the simple (?(R). The condition is true only if the most recent
666            recursion is that of the given number or name. It does not search out
667            through the entire recursion stack.
669        (g) The escape \gN or \g{N} has been added, where N is a positive or
670            negative number, specifying an absolute or relative reference.
672    35. Tidied to get rid of some further signed/unsigned compiler warnings and
673        some "unreachable code" warnings.
675    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
676        things, this adds five new scripts.
678    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
679        There were also incompatibilities regarding the handling of \Q..\E inside
680        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
681        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
683    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
684        matches an empty string, and forcibly breaks the loop. There were bugs in
685        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
686        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
687        separate and independent bugs (that affected different cases) have been
688        fixed.
690    39. Refactored the code to abolish the use of different opcodes for small
691        capturing bracket numbers. This is a tidy that I avoided doing when I
692        removed the limit on the number of capturing brackets for 3.5 back in 2001.
693        The new approach is not only tidier, it makes it possible to reduce the
694        memory needed to fix the previous bug (38).
696    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
697        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
698        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
699        mode.
701    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
702        report.
704    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
705        copy construction and assignment in the C++ wrapper.
707    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
708        couple of bugs that could have given wrong results in the "--newline=crlf"
709        case.
711    44. Added a number of casts and did some reorganization of signed/unsigned int
712        variables following suggestions from Dair Grant. Also renamed the variable
713        "this" as "item" because it is a C++ keyword.
715    45. Arranged for dftables to add
717          #include "pcre_internal.h"
719        to pcre_chartables.c because without it, gcc 4.x may remove the array
720        definition from the final binary if PCRE is built into a static library and
721        dead code stripping is activated.
723    46. For an unanchored pattern, if a match attempt fails at the start of a
724        newline sequence, and the newline setting is CRLF or ANY, and the next two
725        characters are CRLF, advance by two characters instead of one.
728    Version 6.7 04-Jul-06
729    ---------------------
731     1. In order to handle tests when input lines are enormously long, pcretest has
732        been re-factored so that it automatically extends its buffers when
733        necessary. The code is crude, but this _is_ just a test program. The
734        default size has been increased from 32K to 50K.
736     2. The code in pcre_study() was using the value of the re argument before
737        testing it for NULL. (Of course, in any sensible call of the function, it
738        won't be NULL.)
740     3. The memmove() emulation function in pcre_internal.h, which is used on
741        systems that lack both memmove() and bcopy() - that is, hardly ever -
742        was missing a "static" storage class specifier.
744     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
745        containing an extended class (one that cannot be represented by a bitmap
746        because it contains high-valued characters or Unicode property items, e.g.
747        [\pZ]). Almost always one would set UTF-8 mode when processing such a
748        pattern, but PCRE should not loop if you do not (it no longer does).
749        [Detail: two cases were found: (a) a repeated subpattern containing an
750        extended class; (b) a recursive reference to a subpattern that followed a
751        previous extended class. It wasn't skipping over the extended class
752        correctly when UTF-8 mode was not set.]
754     5. A negated single-character class was not being recognized as fixed-length
755        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
756        compile error "lookbehind assertion is not fixed length".
758     6. The RunPerlTest auxiliary script was showing an unexpected difference
759        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
760        write a Perl script that can interpret lines of an input file either as
761        byte characters or as UTF-8, which is what "perltest" was being required to
762        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
763        can't do is switch easily at run time between having the "use utf8;" pragma
764        or not. In the end, I fudged it by using the RunPerlTest script to insert
765        "use utf8;" explicitly for the UTF-8 tests.
767     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
768        the end of the subject string, contrary to the documentation and to what
769        Perl does. This was true of both matching functions. Now it matches only at
770        the start of the subject and immediately after *internal* newlines.
772     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
773        a pointer to an int instead of a pointer to an unsigned long int. This
774        caused problems on 64-bit systems.
776     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
777        instance of the 'standard' template library not being so standard".
779    10. There was no check on the number of named subpatterns nor the maximum
780        length of a subpattern name. The product of these values is used to compute
781        the size of the memory block for a compiled pattern. By supplying a very
782        long subpattern name and a large number of named subpatterns, the size
783        computation could be caused to overflow. This is now prevented by limiting
784        the length of names to 32 characters, and the number of named subpatterns
785        to 10,000.
787    11. Subpatterns that are repeated with specific counts have to be replicated in
788        the compiled pattern. The size of memory for this was computed from the
789        length of the subpattern and the repeat count. The latter is limited to
790        65535, but there was no limit on the former, meaning that integer overflow
791        could in principle occur. The compiled length of a repeated subpattern is
792        now limited to 30,000 bytes in order to prevent this.
794    12. Added the optional facility to have named substrings with the same name.
796    13. Added the ability to use a named substring as a condition, using the
797        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
798        are numbers (not recommended). Forward references are permitted.
800    14. Added forward references in named backreferences (if you see what I mean).
802    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
803        pattern could run off the end of the subject. For example, the pattern
804        "(?s)(.{1,5})"8 did this with the subject "ab".
806    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
807        PCRE_CASELESS was set when matching characters that were quantified with ?
808        or *.
810    17. A character class other than a single negated character that had a minimum
811        but no maximum quantifier - for example [ab]{6,} - was not handled
812        correctly by pce_dfa_exec(). It would match only one character.
814    18. A valid (though odd) pattern that looked like a POSIX character
815        class but used an invalid character after [ (for example [[,abc,]]) caused
816        pcre_compile() to give the error "Failed: internal error: code overflow" or
817        in some cases to crash with a glibc free() error. This could even happen if
818        the pattern terminated after [[ but there just happened to be a sequence of
819        letters, a binary zero, and a closing ] in the memory that followed.
821    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
822        over the years. Originally (before any Unicode support), just the bottom 8
823        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
824        output from "man perlunicode" includes this:
826          The regular expression compiler produces polymorphic opcodes.  That
827          is, the pattern adapts to the data and automatically switches to
828          the Unicode character scheme when presented with Unicode data--or
829          instead uses a traditional byte scheme when presented with byte
830          data.
832        Sadly, a wide octal escape does not cause a switch, and in a string with
833        no other multibyte characters, these octal escapes are treated as before.
834        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
835        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
836        Unicode string.
838        I have not perpetrated such confusion in PCRE. Up till now, it took just
839        the bottom 8 bits, as in old Perl. I have now made octal escapes with
840        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
841        translate to the appropriate multibyte character.
843    29. Applied some refactoring to reduce the number of warnings from Microsoft
844        and Borland compilers. This has included removing the fudge introduced
845        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
846        a warning about an unused variable.
848    21. PCRE has not included VT (character 0x0b) in the set of whitespace
849        characters since release 4.0, because Perl (from release 5.004) does not.
850        [Or at least, is documented not to: some releases seem to be in conflict
851        with the documentation.] However, when a pattern was studied with
852        pcre_study() and all its branches started with \s, PCRE still included VT
853        as a possible starting character. Of course, this did no harm; it just
854        caused an unnecessary match attempt.
856    22. Removed a now-redundant internal flag bit that recorded the fact that case
857        dependency changed within the pattern. This was once needed for "required
858        byte" processing, but is no longer used. This recovers a now-scarce options
859        bit. Also moved the least significant internal flag bit to the most-
860        significant bit of the word, which was not previously used (hangover from
861        the days when it was an int rather than a uint) to free up another bit for
862        the future.
864    23. Added support for CRLF line endings as well as CR and LF. As well as the
865        default being selectable at build time, it can now be changed at runtime
866        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
867        specify that it is scanning data with non-default line endings.
869    24. Changed the definition of CXXLINK to make it agree with the definition of
870        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
872    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
873        recursions. This makes a big different to stack usage for some patterns.
875    26. If a subpattern containing a named recursion or subroutine reference such
876        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
877        the space required for the compiled pattern went wrong and gave too small a
878        value. Depending on the environment, this could lead to "Failed: internal
879        error: code overflow at offset 49" or "glibc detected double free or
880        corruption" errors.
882    27. Applied patches from Google (a) to support the new newline modes and (b) to
883        advance over multibyte UTF-8 characters in GlobalReplace.
885    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
886        difference for some implementation of PCRE in some Windows version.
888    29. Added some extra testing facilities to pcretest:
890        \q<number>   in a data line sets the "match limit" value
891        \Q<number>   in a data line sets the "match recursion limt" value
892        -S <number>  sets the stack size, where <number> is in megabytes
894        The -S option isn't available for Windows.
897    Version 6.6 06-Feb-06
898    ---------------------
900     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
901        in pcreposix.h. I have copied the definition from pcre.h.
903     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
904        because pcre.h is no longer a built file.
906     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
907        not normally included in the compiled code.
910    Version 6.5 01-Feb-06
911    ---------------------
913     1. When using the partial match feature with pcre_dfa_exec(), it was not
914        anchoring the second and subsequent partial matches at the new starting
915        point. This could lead to incorrect results. For example, with the pattern
916        /1234/, partially matching against "123" and then "a4" gave a match.
918     2. Changes to pcregrep:
920        (a) All non-match returns from pcre_exec() were being treated as failures
921            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
922            error message is output. Some extra information is given for the
923            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
924            probably the only errors that are likely to be caused by users (by
925            specifying a regex that has nested indefinite repeats, for instance).
926            If there are more than 20 of these errors, pcregrep is abandoned.
928        (b) A binary zero was treated as data while matching, but terminated the
929            output line if it was written out. This has been fixed: binary zeroes
930            are now no different to any other data bytes.
932        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
933            used to set a locale for matching. The --locale=xxxx long option has
934            been added (no short equivalent) to specify a locale explicitly on the
935            pcregrep command, overriding the environment variables.
937        (d) When -B was used with -n, some line numbers in the output were one less
938            than they should have been.
940        (e) Added the -o (--only-matching) option.
942        (f) If -A or -C was used with -c (count only), some lines of context were
943            accidentally printed for the final match.
945        (g) Added the -H (--with-filename) option.
947        (h) The combination of options -rh failed to suppress file names for files
948            that were found from directory arguments.
950        (i) Added the -D (--devices) and -d (--directories) options.
952        (j) Added the -F (--fixed-strings) option.
954        (k) Allow "-" to be used as a file name for -f as well as for a data file.
956        (l) Added the --colo(u)r option.
958        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
959            is not present by default.
961     3. A nasty bug was discovered in the handling of recursive patterns, that is,
962        items such as (?R) or (?1), when the recursion could match a number of
963        alternatives. If it matched one of the alternatives, but subsequently,
964        outside the recursion, there was a failure, the code tried to back up into
965        the recursion. However, because of the way PCRE is implemented, this is not
966        possible, and the result was an incorrect result from the match.
968        In order to prevent this happening, the specification of recursion has
969        been changed so that all such subpatterns are automatically treated as
970        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
972     4. I had overlooked the fact that, in some locales, there are characters for
973        which isalpha() is true but neither isupper() nor islower() are true. In
974        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
975        and ordfeminine) are like this. This affected the treatment of \w and \W
976        when they appeared in character classes, but not when they appeared outside
977        a character class. The bit map for "word" characters is now created
978        separately from the results of isalnum() instead of just taking it from the
979        upper, lower, and digit maps. (Plus the underscore character, of course.)
981     5. The above bug also affected the handling of POSIX character classes such as
982        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
983        permanent tables. Instead, the bit maps for such a class were previously
984        created as the appropriate unions of the upper, lower, and digit bitmaps.
985        Now they are created by subtraction from the [[:word:]] class, which has
986        its own bitmap.
988     6. The [[:blank:]] character class matches horizontal, but not vertical space.
989        It is created by subtracting the vertical space characters (\x09, \x0a,
990        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
991        subtraction was done in the overall bitmap for a character class, meaning
992        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
993        be recognized. This bug has been fixed.
995     7. Patches from the folks at Google:
997          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
998          real life, but is still worth protecting against".
1000          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1001          regular expressions".
1003          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1004          have it.
1006          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1007          "configure" and the latter not, in order to fix a problem somebody had
1008          with compiling the Arg class on HP-UX.
1010          (e) Improve the error-handling of the C++ wrapper a little bit.
1012          (f) New tests for checking recursion limiting.
1014     8. The pcre_memmove() function, which is used only if the environment does not
1015        have a standard memmove() function (and is therefore rarely compiled),
1016        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1017        returning a result (though PCRE never actually uses the result).
1019     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1020        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1021        returned instead of calling malloc() with an overflowing number that would
1022        most likely cause subsequent chaos.
1024    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1026    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1027        with this option is matched, the nmatch and pmatch options of regexec() are
1028        ignored.
1030    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1031        provided in case anyone wants to the the POSIX interface with UTF-8
1032        strings.
1034    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1035        C++ linking (needed for some HP-UX environments).
1037    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1038        (unused parameter) and in the pcre_printint() function (omitted "default"
1039        switch label when the default is to do nothing).
1041    15. Added some code to make it possible, when PCRE is compiled as a C++
1042        library, to replace subject pointers for pcre_exec() with a smart pointer
1043        class, thus making it possible to process discontinuous strings.
1045    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1046        much the same function. They were added by different people who were trying
1047        to make PCRE easy to compile on non-Unix systems. It has been suggested
1048        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1049        for compiling on Windows systems. I have therefore replaced it with
1050        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1051        defaults to "extern" for C or "extern C" for C++, which works fine on
1052        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1053        SCOPE with something explicit in config.h. In addition:
1055        (a) pcreposix.h still had just "extern" instead of either of these macros;
1056            I have replaced it with PCRE_DATA_SCOPE.
1058        (b) Functions such as _pcre_xclass(), which are internal to the library,
1059            but external in the C sense, all had PCRE_EXPORT in their definitions.
1060            This is apparently wrong for the Windows case, so I have removed it.
1061            (It makes no difference on Unix-like systems.)
1063    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1064        of recursive calls to match(). This is different to MATCH_LIMIT because
1065        that limits the total number of calls to match(), not all of which increase
1066        the depth of recursion. Limiting the recursion depth limits the amount of
1067        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1068        when PCRE is compiled, and changed at run time. A patch from Google adds
1069        this functionality to the C++ interface.
1071    18. Changes to the handling of Unicode character properties:
1073        (a) Updated the table to Unicode 4.1.0.
1075        (b) Recognize characters that are not in the table as "Cn" (undefined).
1077        (c) I revised the way the table is implemented to a much improved format
1078            which includes recognition of ranges. It now supports the ranges that
1079            are defined in UnicodeData.txt, and it also amalgamates other
1080            characters into ranges. This has reduced the number of entries in the
1081            table from around 16,000 to around 3,000, thus reducing its size
1082            considerably. I realized I did not need to use a tree structure after
1083            all - a binary chop search is just as efficient. Having reduced the
1084            number of entries, I extended their size from 6 bytes to 8 bytes to
1085            allow for more data.
1087        (d) Added support for Unicode script names via properties such as \p{Han}.
1089    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1090        matching that character.
1092    20. When matching a repeated Unicode property with a minimum greater than zero,
1093        (for example \pL{2,}), PCRE could look past the end of the subject if it
1094        reached it while seeking the minimum number of characters. This could
1095        happen only if some of the characters were more than one byte long, because
1096        there is a check for at least the minimum number of bytes.
1098    21. Refactored the implementation of \p and \P so as to be more general, to
1099        allow for more different types of property in future. This has changed the
1100        compiled form incompatibly. Anybody with saved compiled patterns that use
1101        \p or \P will have to recompile them.
1103    22. Added "Any" and "L&" to the supported property types.
1105    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1106        but give a compile time error if the value is greater than 0xff.
1108    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1109        accidentally not being installed or uninstalled.
1111    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1112        made were to insert the current release number. This seemed silly, because
1113        it made things harder for people building PCRE on systems that don't run
1114        "configure". I have turned pcre.h into a distributed file, no longer built
1115        by "configure", with the version identification directly included. There is
1116        no longer a pcre.h.in file.
1118        However, this change necessitated a change to the pcre-config script as
1119        well. It is built from pcre-config.in, and one of the substitutions was the
1120        release number. I have updated configure.ac so that ./configure now finds
1121        the release number by grepping pcre.h.
1123    26. Added the ability to run the tests under valgrind.
1126    Version 6.4 05-Sep-05
1127    ---------------------
1129     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1130        "--" to be printed when multiple files were scanned, even when none of the
1131        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1132        consider it to be a bug, and have restored the previous behaviour.
1134     2. A couple of code tidies to get rid of compiler warnings.
1136     3. The pcretest program used to cheat by referring to symbols in the library
1137        whose names begin with _pcre_. These are internal symbols that are not
1138        really supposed to be visible externally, and in some environments it is
1139        possible to suppress them. The cheating is now confined to including
1140        certain files from the library's source, which is a bit cleaner.
1142     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1143        file's purpose clearer.
1145     5. Reorganized pcre_ucp_findchar().
1148    Version 6.3 15-Aug-05
1149    ---------------------
1151     1. The file libpcre.pc.in did not have general read permission in the tarball.
1153     2. There were some problems when building without C++ support:
1155        (a) If C++ support was not built, "make install" and "make test" still
1156            tried to test it.
1158        (b) There were problems when the value of CXX was explicitly set. Some
1159            changes have been made to try to fix these, and ...
1161        (c) --disable-cpp can now be used to explicitly disable C++ support.
1163        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1164            backslash in a target when C++ was disabled. This confuses some
1165            versions of "make", apparently. Using an intermediate variable solves
1166            this. (Same for CPP_LOBJ.)
1168     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1169        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1170        necessary on certain architectures.
1172     4. Added a setting of -export-symbols-regex to the link command to remove
1173        those symbols that are exported in the C sense, but actually are local
1174        within the library, and not documented. Their names all begin with
1175        "_pcre_". This is not a perfect job, because (a) we have to except some
1176        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1177        available (and never for static libraries). I have made a note to try to
1178        find a way round (a) in the future.
1181    Version 6.2 01-Aug-05
1182    ---------------------
1184     1. There was no test for integer overflow of quantifier values. A construction
1185        such as {1111111111111111} would give undefined results. What is worse, if
1186        a minimum quantifier for a parenthesized subpattern overflowed and became
1187        negative, the calculation of the memory size went wrong. This could have
1188        led to memory overwriting.
1190     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1192     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1193        operating environments where this matters.
1195     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1196        PCRE options from within the C++ wrapper.
1198     5. Named capturing subpatterns were not being correctly counted when a pattern
1199        was compiled. This caused two problems: (a) If there were more than 100
1200        such subpatterns, the calculation of the memory needed for the whole
1201        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1202        back references of the form \12, where the number was greater than 9, were
1203        not recognized as back references, even though there were sufficient
1204        previous subpatterns.
1206     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1207        versions of gcc, e.g. 2.95.4.
1210    Version 6.1 21-Jun-05
1211    ---------------------
1213     1. There was one reference to the variable "posix" in pcretest.c that was not
1214        surrounded by "#if !defined NOPOSIX".
1216     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1217        the cross-check on the old pcre_info() function, for the benefit of the
1218        cut-down version of PCRE that is currently imported into Exim.
1220     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1221        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1222        patterns that start (?i) but I don't think that matters. The use of (?i) is
1223        just an example; this all applies to the other options as well.
1225     4. Since libtool seems to echo the compile commands it is issuing, the output
1226        from "make" can be reduced a bit by putting "@" in front of each libtool
1227        compile command.
1229     5. Patch from the folks at Google for configure.in to be a bit more thorough
1230        in checking for a suitable C++ installation before trying to compile the
1231        C++ stuff. This should fix a reported problem when a compiler was present,
1232        but no suitable headers.
1234     6. The man pages all had just "PCRE" as their title. I have changed them to
1235        be the relevant file name. I have also arranged that these names are
1236        retained in the file doc/pcre.txt, which is a concatenation in text format
1237        of all the man pages except the little individual ones for each function.
1239     7. The NON-UNIX-USE file had not been updated for the different set of source
1240        files that come with release 6. I also added a few comments about the C++
1241        wrapper.
1244    Version 6.0 07-Jun-05
1245    ---------------------
1247     1. Some minor internal re-organization to help with my DFA experiments.
1249     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1250        didn't matter for the library itself when fully configured, but did matter
1251        when compiling without UCP support, or within Exim, where the ucp files are
1252        not imported.
1254     3. Refactoring of the library code to split up the various functions into
1255        different source modules. The addition of the new DFA matching code (see
1256        below) to a single monolithic source would have made it really too
1257        unwieldy, quite apart from causing all the code to be include in a
1258        statically linked application, when only some functions are used. This is
1259        relevant even without the DFA addition now that patterns can be compiled in
1260        one application and matched in another.
1262        The downside of splitting up is that there have to be some external
1263        functions and data tables that are used internally in different modules of
1264        the library but which are not part of the API. These have all had their
1265        names changed to start with "_pcre_" so that they are unlikely to clash
1266        with other external names.
1268     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1269        a different (DFA) algorithm. Although it is slower than the original
1270        function, it does have some advantages for certain types of matching
1271        problem.
1273     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1274        including restarting after a partial match.
1276     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1277        defined when compiling for Windows was sent to me. I have put it into the
1278        code, though I have no means of testing or verifying it.
1280     7. Added the pcre_refcount() auxiliary function.
1282     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1283        match before or at the first newline in the subject string. In pcretest,
1284        the /f option on a pattern can be used to set this.
1286     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1287        would behave wrongly. This has been present in PCRE since release 4.0.
1289    10. A number of changes to the pcregrep command:
1291        (a) Refactored how -x works; insert ^(...)$ instead of setting
1292            PCRE_ANCHORED and checking the length, in preparation for adding
1293            something similar for -w.
1295        (b) Added the -w (match as a word) option.
1297        (c) Refactored the way lines are read and buffered so as to have more
1298            than one at a time available.
1300        (d) Implemented a pcregrep test script.
1302        (e) Added the -M (multiline match) option. This allows patterns to match
1303            over several lines of the subject. The buffering ensures that at least
1304            8K, or the rest of the document (whichever is the shorter) is available
1305            for matching (and similarly the previous 8K for lookbehind assertions).
1307        (f) Changed the --help output so that it now says
1309              -w, --word-regex(p)
1311            instead of two lines, one with "regex" and the other with "regexp"
1312            because that confused at least one person since the short forms are the
1313            same. (This required a bit of code, as the output is generated
1314            automatically from a table. It wasn't just a text change.)
1316        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1317            option but starts with a hyphen. Could be a pattern or a path name
1318            starting with a hyphen, for instance.
1320        (h) "-" can be given as a file name to represent stdin.
1322        (i) When file names are being printed, "(standard input)" is used for
1323            the standard input, for compatibility with GNU grep. Previously
1324            "<stdin>" was used.
1326        (j) The option --label=xxx can be used to supply a name to be used for
1327            stdin when file names are being printed. There is no short form.
1329        (k) Re-factored the options decoding logic because we are going to add
1330            two more options that take data. Such options can now be given in four
1331            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1333        (l) Added the -A, -B, and -C options for requesting that lines of context
1334            around matches be printed.
1336        (m) Added the -L option to print the names of files that do not contain
1337            any matching lines, that is, the complement of -l.
1339        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1340            continue to scan other files.
1342        (o) The -s option was incorrectly implemented. For compatibility with other
1343            greps, it now suppresses the error message for a non-existent or non-
1344            accessible file (but not the return code). There is a new option called
1345            -q that suppresses the output of matching lines, which was what -s was
1346            previously doing.
1348        (p) Added --include and --exclude options to specify files for inclusion
1349            and exclusion when recursing.
1351    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1352        Hopefully, it now does.
1354    12. Missing cast in pcre_study().
1356    13. Added an "uninstall" target to the makefile.
1358    14. Replaced "extern" in the function prototypes in Makefile.in with
1359        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1360        world, but is set differently for Windows.
1362    15. Added a second compiling function called pcre_compile2(). The only
1363        difference is that it has an extra argument, which is a pointer to an
1364        integer error code. When there is a compile-time failure, this is set
1365        non-zero, in addition to the error test pointer being set to point to an
1366        error message. The new argument may be NULL if no error number is required
1367        (but then you may as well call pcre_compile(), which is now just a
1368        wrapper). This facility is provided because some applications need a
1369        numeric error indication, but it has also enabled me to tidy up the way
1370        compile-time errors are handled in the POSIX wrapper.
1372    16. Added VPATH=.libs to the makefile; this should help when building with one
1373        prefix path and installing with another. (Or so I'm told by someone who
1374        knows more about this stuff than I do.)
1376    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1377        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1378        match everything, including newlines. This is not POSIX-compatible, but
1379        somebody wanted the feature. From pcretest it can be activated by using
1380        both the P and the s flags.
1382    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1384    19. libpcre.pc was being incorrectly installed as executable.
1386    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1387        it now also looks for '\r' so that it will work unmodified on Windows.
1389    21. Added Google's contributed C++ wrapper to the distribution.
1391    22. Added some untidy missing memory free() calls in pcretest, to keep
1392        Electric Fence happy when testing.
1396    Version 5.0 13-Sep-04
1397    ---------------------
1399     1. Internal change: literal characters are no longer packed up into items
1400        containing multiple characters in a single byte-string. Each character
1401        is now matched using a separate opcode. However, there may be more than one
1402        byte in the character in UTF-8 mode.
1404     2. The pcre_callout_block structure has two new fields: pattern_position and
1405        next_item_length. These contain the offset in the pattern to the next match
1406        item, and its length, respectively.
1408     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1409        insertion of callouts before each pattern item. Added the /C option to
1410        pcretest to make use of this.
1412     4. On the advice of a Windows user, the lines
1414          #if defined(_WIN32) || defined(WIN32)
1415          _setmode( _fileno( stdout ), 0x8000 );
1416          #endif  /* defined(_WIN32) || defined(WIN32) */
1418        have been added to the source of pcretest. This apparently does useful
1419        magic in relation to line terminators.
1421     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1422        for the benefit of those environments where the "b" makes a difference.
1424     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1425        to know about it. I have put a hack into configure.in that adds in code
1426        to set GCC=yes if CC=icc. This seems to end up at a point in the
1427        generated configure script that is early enough to affect the setting of
1428        compiler options, which is what is needed, but I have no means of testing
1429        whether it really works. (The user who reported this had patched the
1430        generated configure script, which of course I cannot do.)
1432        LATER: After change 22 below (new libtool files), the configure script
1433        seems to know about icc (and also ecc). Therefore, I have commented out
1434        this hack in configure.in.
1436     7. Added support for pkg-config (2 patches were sent in).
1438     8. Negated POSIX character classes that used a combination of internal tables
1439        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1440        [[:^ascii]]. Typically, they would match almost any characters. The other
1441        POSIX classes were not broken in this way.
1443     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1444        to find the match, as PCRE was deluded into thinking that the match had to
1445        start at the start point or following a newline. The same bug applied to
1446        patterns with negative forward assertions or any backward assertions
1447        preceding ".*" at the start, unless the pattern required a fixed first
1448        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1450    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1451        starting at the last subject character, bytes beyond the end of the subject
1452        string were read.
1454    11. Renamed the variable "class" as "classbits" to make life easier for C++
1455        users. (Previously there was a macro definition, but it apparently wasn't
1456        enough.)
1458    12. Added the new field "tables" to the extra data so that tables can be passed
1459        in at exec time, or the internal tables can be re-selected. This allows
1460        a compiled regex to be saved and re-used at a later time by a different
1461        program that might have everything at different addresses.
1463    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1464        -R library as well as a -L library.
1466    14. The debugging options of pcretest (-d on the command line or D on a
1467        pattern) showed incorrect output for anything following an extended class
1468        that contained multibyte characters and which was followed by a quantifier.
1470    15. Added optional support for general category Unicode character properties
1471        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1472        support. It adds about 90K to the size of the library. The meanings of the
1473        inbuilt class escapes such as \d and \s have NOT been changed.
1475    16. Updated pcredemo.c to include calls to free() to release the memory for the
1476        compiled pattern.
1478    17. The generated file chartables.c was being created in the source directory
1479        instead of in the building directory. This caused the build to fail if the
1480        source directory was different from the building directory, and was
1481        read-only.
1483    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1484        file. No doubt somebody will tell me if they don't make sense... Also added
1485        Dan Mooney's comments about building on OpenVMS.
1487    19. Added support for partial matching via the PCRE_PARTIAL option for
1488        pcre_exec() and the \P data escape in pcretest.
1490    20. Extended pcretest with 3 new pattern features:
1492        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1493              write the compiled pattern to the file whose name is "rest-of-line".
1494              This is a straight binary dump of the data, with the saved pointer to
1495              the character tables forced to be NULL. The study data, if any, is
1496              written too. After writing, pcretest reads a new pattern.
1498        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1499              compiled pattern from the given file. There must not be any
1500              occurrences of "<" in the file name (pretty unlikely); if there are,
1501              pcretest will instead treat the initial "<" as a pattern delimiter.
1502              After reading in the pattern, pcretest goes on to read data lines as
1503              usual.
1505        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1506              and 16-bit fields in a compiled pattern, to simulate a pattern that
1507              was compiled on a host of opposite endianness.
1509    21. The pcre-exec() function can now cope with patterns that were compiled on
1510        hosts of opposite endianness, with this restriction:
1512          As for any compiled expression that is saved and used later, the tables
1513          pointer field cannot be preserved; the extra_data field in the arguments
1514          to pcre_exec() should be used to pass in a tables address if a value
1515          other than the default internal tables were used at compile time.
1517    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1518        now diagnosed as an error. Previously, most of the time, a negative number
1519        would have been treated as zero, but if in addition "ovector" was passed as
1520        NULL, a crash could occur.
1522    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1523        new versions from the libtool 1.5 distribution (the last one is a copy of
1524        a file called libtool.m4). This seems to have fixed the need to patch
1525        "configure" to support Darwin 1.3 (which I used to do). However, I still
1526        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1527        workstation).
1529    24. Changed the PCRE licence to be the more standard "BSD" licence.
1532    Version 4.5 01-Dec-03
1533    ---------------------
1535     1. There has been some re-arrangement of the code for the match() function so
1536        that it can be compiled in a version that does not call itself recursively.
1537        Instead, it keeps those local variables that need separate instances for
1538        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1539        needs to "recurse". Keeping track of where control must go is done by means
1540        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1541        hide most of the details from the main code, and operates only if
1542        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1543        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1544        operating.
1546        To make it easier for callers to provide specially tailored get/free
1547        functions for this usage, two new functions, pcre_stack_malloc, and
1548        pcre_stack_free, are used. They are always called in strict stacking order,
1549        and the size of block requested is always the same.
1551        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1552        PCRE has been compiled to use the stack or the heap for recursion. The
1553        -C option of pcretest uses this to show which version is compiled.
1555        A new data escape \S, is added to pcretest; it causes the amounts of store
1556        obtained and freed by both kinds of malloc/free at match time to be added
1557        to the output.
1559     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1560        what's available on my current Linux desktop machine.
1562     3. When matching a UTF-8 string, the test for a valid string at the start has
1563        been extended. If start_offset is not zero, PCRE now checks that it points
1564        to a byte that is the start of a UTF-8 character. If not, it returns
1565        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1566        this is necessary because there may be backward assertions in the pattern.
1567        When matching the same subject several times, it may save resources to use
1568        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1570     4. The code for checking the validity of UTF-8 strings has been tightened so
1571        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1572        containing "overlong sequences".
1574     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1575        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1576        should have been "&", but it just so happened that all the cases this let
1577        through by mistake were picked up later in the function.
1579     6. I had used a variable called "isblank" - this is a C99 function, causing
1580        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1582     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1583        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1584        so the version is shown; (c) stop "make test" echoing "./RunTest".
1586     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1588     9. The prototype for memmove() for systems that don't have it was using
1589        size_t, but the inclusion of the header that defines size_t was later. I've
1590        moved the #includes for the C headers earlier to avoid this.
1592    10. Added some adjustments to the code to make it easier to compiler on certain
1593        special systems:
1595          (a) Some "const" qualifiers were missing.
1596          (b) Added the macro EXPORT before all exported functions; by default this
1597              is defined to be empty.
1598          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1599              that it reads its output file name as an argument instead of writing
1600              to the standard output and assuming this can be redirected.
1602    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1603        class containing characters with values greater than 255, PCRE compilation
1604        went into a loop.
1606    12. A recursive reference to a subpattern that was within another subpattern
1607        that had a minimum quantifier of zero caused PCRE to crash. For example,
1608        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1609        recursion. If the recursively-called subpattern itself had a zero repeat,
1610        that was OK.
1612    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1613        buffer into which it was copied (for escape processing) was still set at
1614        1024, so long lines caused crashes.
1616    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1617        "internal error: code overflow...". This applied to any character class
1618        that was followed by a possessive quantifier.
1620    15. Modified the Makefile to add libpcre.la as a prerequisite for
1621        libpcreposix.la because I was told this is needed for a parallel build to
1622        work.
1624    16. If a pattern that contained .* following optional items at the start was
1625        studied, the wrong optimizing data was generated, leading to matching
1626        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1627        matching string must start with a or b or c. The correct conclusion for
1628        this pattern is that a match can start with any character.
1631    Version 4.4 13-Aug-03
1632    ---------------------
1634     1. In UTF-8 mode, a character class containing characters with values between
1635        127 and 255 was not handled correctly if the compiled pattern was studied.
1636        In fixing this, I have also improved the studying algorithm for such
1637        classes (slightly).
1639     2. Three internal functions had redundant arguments passed to them. Removal
1640        might give a very teeny performance improvement.
1642     3. Documentation bug: the value of the capture_top field in a callout is *one
1643        more than* the number of the hightest numbered captured substring.
1645     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1646        in incorrectly linking with a previously installed version. They now link
1647        explicitly with libpcre.la.
1649     5. configure.in no longer needs to recognize Cygwin specially.
1651     6. A problem in pcre.in for Windows platforms is fixed.
1653     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1654        pcretest, it used to include the size of the study block as part of its
1655        output. Unfortunately, the structure contains a field that has a different
1656        size on different hardware architectures. This meant that the tests that
1657        showed this size failed. As the block is currently always of a fixed size,
1658        this information isn't actually particularly useful in pcretest output, so
1659        I have just removed it.
1661     8. Three pre-processor statements accidentally did not start in column 1.
1662        Sadly, there are *still* compilers around that complain, even though
1663        standard C has not required this for well over a decade. Sigh.
1665     9. In pcretest, the code for checking callouts passed small integers in the
1666        callout_data field, which is a void * field. However, some picky compilers
1667        complained about the casts involved for this on 64-bit systems. Now
1668        pcretest passes the address of the small integer instead, which should get
1669        rid of the warnings.
1671    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1672        both compile and run time, and gives an error if an invalid UTF-8 sequence
1673        is found. There is a option for disabling this check in cases where the
1674        string is known to be correct and/or the maximum performance is wanted.
1676    11. In response to a bug report, I changed one line in Makefile.in from
1678            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1679        to
1680            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1682        to look similar to other lines, but I have no way of telling whether this
1683        is the right thing to do, as I do not use Windows. No doubt I'll get told
1684        if it's wrong...
1687    Version 4.3 21-May-03
1688    ---------------------
1690    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1691       Makefile.
1693    2. Some refactoring to improve the quality of the code:
1695       (i)   The utf8_table... variables are now declared "const".
1697       (ii)  The code for \cx, which used the "case flipping" table to upper case
1698             lower case letters, now just substracts 32. This is ASCII-specific,
1699             but the whole concept of \cx is ASCII-specific, so it seems
1700             reasonable.
1702       (iii) PCRE was using its character types table to recognize decimal and
1703             hexadecimal digits in the pattern. This is silly, because it handles
1704             only 0-9, a-f, and A-F, but the character types table is locale-
1705             specific, which means strange things might happen. A private
1706             table is now used for this - though it costs 256 bytes, a table is
1707             much faster than multiple explicit tests. Of course, the standard
1708             character types table is still used for matching digits in subject
1709             strings against \d.
1711       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1712             ending in _t are). So I've renamed it as ESC_tee.
1714    3. The first argument for regexec() in the POSIX wrapper should have been
1715       defined as "const".
1717    4. Changed pcretest to use malloc() for its buffers so that they can be
1718       Electric Fenced for debugging.
1720    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1721       to read one or more bytes before the start of the subject string. Often this
1722       had no effect on PCRE's behaviour, but in some circumstances it could
1723       provoke a segmentation fault.
1725    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1726       to try to read one or more bytes before the start of the subject string.
1728    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1729       UTF-8 support could misbehave in various ways if the subject string
1730       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1731       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1732       back over UTF-8 characters.)
1735    Version 4.2 14-Apr-03
1736    ---------------------
1738    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1740    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1741         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1742         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1743         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1744         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1745           and BUILD_EXEEXT
1746         Note: automatic setting of the BUILD variables is not yet working
1747         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1748           compile-time but not at link-time
1749         [LINK]: use for linking executables only
1750         make different versions for Windows and non-Windows
1751         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1752           libraries
1753         [LINK_FOR_BUILD]: new variable
1754         [OBJEXT]: use throughout
1755         [EXEEXT]: use throughout
1756         <winshared>: new target
1757         <wininstall>: new target
1758         <dftables.o>: use native compiler
1759         <dftables>: use native linker
1760         <install>: handle Windows platform correctly
1761         <clean>: ditto
1762         <check>: ditto
1763         copy DLL to top builddir before testing
1765       As part of these changes, -no-undefined was removed again. This was reported
1766       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1767       in any case.
1769    3. Some tidies to get rid of compiler warnings:
1771       . In the match_data structure, match_limit was an unsigned long int, whereas
1772         match_call_count was an int. I've made them both unsigned long ints.
1774       . In pcretest the fact that a const uschar * doesn't automatically cast to
1775         a void * provoked a warning.
1777       . Turning on some more compiler warnings threw up some "shadow" variables
1778         and a few more missing casts.
1780    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1781       option, a class that contained a single character with a value between 128
1782       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1784    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1785       option, a class that contained several characters, but with at least one
1786       whose value was between 128 and 255 caused PCRE to crash.
1789  Version 4.1 12-Mar-03  Version 4.1 12-Mar-03
1790  ---------------------  ---------------------

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