/[pcre]/code/tags/pcre-8.01/ChangeLog
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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 255 by ph10, Wed Sep 19 08:50:04 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.4 10-Sep-07
5    ---------------------
6    
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.
13    
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.
19    
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.
25    
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.
28    
29    5.  doc/pcresyntax.html was missing from the distribution.
30    
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
33    
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).
37    
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".
40    
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
43    
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:
49    
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
55    
56        Thanks to the folks working on Gregex for glib for this insight.
57    
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
60    
61    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
62    
63    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
64        checked only for CRLF.
65    
66    14. Added casts to pcretest.c to avoid compiler warnings.
67    
68    
69    Version 7.3 28-Aug-07
70    ---------------------
71    
72     1. In the rejigging of the build system that eventually resulted in 7.1, the
73        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
74        brackets there is not right, since it causes compilers to look for an
75        installed pcre.h, not the version that is in the source that is being
76        compiled (which of course may be different). I have changed it back to:
77    
78          #include "pcre.h"
79    
80        I have a vague recollection that the change was concerned with compiling in
81        different directories, but in the new build system, that is taken care of
82        by the VPATH setting the Makefile.
83    
84     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
85        when the subject happened to end in the byte 0x85 (e.g. if the last
86        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
87        characters but of course it shouldn't be taken as a newline when it is part
88        of another character. The bug was that, for an unlimited repeat of . in
89        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
90        characters when looking for a newline.
91    
92     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
93    
94     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
95        in debug output.
96    
97     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
98        long printing in the pcrecpp unittest when running under MinGW.
99    
100     6. ESC_K was left out of the EBCDIC table.
101    
102     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
103        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
104        limit also applies to "virtual nesting" when a pattern is recursive, and in
105        this case 1000 isn't so big. I have been able to remove this limit at the
106        expense of backing off one optimization in certain circumstances. Normally,
107        when pcre_exec() would call its internal match() function recursively and
108        immediately return the result unconditionally, it uses a "tail recursion"
109        feature to save stack. However, when a subpattern that can match an empty
110        string has an unlimited repetition quantifier, it no longer makes this
111        optimization. That gives it a stack frame in which to save the data for
112        checking that an empty string has been matched. Previously this was taken
113        from the 1000-entry workspace that had been reserved. So now there is no
114        explicit limit, but more stack is used.
115    
116     8. Applied Daniel's patches to solve problems with the import/export magic
117        syntax that is required for Windows, and which was going wrong for the
118        pcreposix and pcrecpp parts of the library. These were overlooked when this
119        problem was solved for the main library.
120    
121     9. There were some crude static tests to avoid integer overflow when computing
122        the size of patterns that contain repeated groups with explicit upper
123        limits. As the maximum quantifier is 65535, the maximum group length was
124        set at 30,000 so that the product of these two numbers did not overflow a
125        32-bit integer. However, it turns out that people want to use groups that
126        are longer than 30,000 bytes (though not repeat them that many times).
127        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
128        made it possible to implement the integer overflow checks in a much more
129        dynamic way, which I have now done. The artificial limitation on group
130        length has been removed - we now have only the limit on the total length of
131        the compiled pattern, which depends on the LINK_SIZE setting.
132    
133    10. Fixed a bug in the documentation for get/copy named substring when
134        duplicate names are permitted. If none of the named substrings are set, the
135        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
136        empty string.
137    
138    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
139        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
140        because the ] is interpreted as the first data character and the
141        terminating ] is not found. PCRE has been made compatible with Perl in this
142        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
143        cause memory overwriting.
144    
145    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
146        string has been matched (to stop an infinite loop). It was not recognizing
147        a conditional subpattern that could match an empty string if that
148        subpattern was within another subpattern. For example, it looped when
149        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
150        condition was not nested. This bug has been fixed.
151    
152    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
153        past the start of the subject in the presence of bytes with the top bit
154        set, for example "\x8aBCD".
155    
156    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
157        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
158    
159    14. Optimized (?!) to (*FAIL).
160    
161    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
162        This restricts code points to be within the range 0 to 0x10FFFF, excluding
163        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
164        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
165        does: it's just the validity check that is more restrictive.
166    
167    16. Inserted checks for integer overflows during escape sequence (backslash)
168        processing, and also fixed erroneous offset values for syntax errors during
169        backslash processing.
170    
171    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
172        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
173    
174    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
175        caused an overrun.
176    
177    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
178        something other than just ASCII characters) inside a group that had an
179        unlimited repeat caused a loop at compile time (while checking to see
180        whether the group could match an empty string).
181    
182    20. Debugging a pattern containing \p or \P could cause a crash. For example,
183        [\P{Any}] did so. (Error in the code for printing property names.)
184    
185    21. An orphan \E inside a character class could cause a crash.
186    
187    22. A repeated capturing bracket such as (A)? could cause a wild memory
188        reference during compilation.
189    
190    23. There are several functions in pcre_compile() that scan along a compiled
191        expression for various reasons (e.g. to see if it's fixed length for look
192        behind). There were bugs in these functions when a repeated \p or \P was
193        present in the pattern. These operators have additional parameters compared
194        with \d, etc, and these were not being taken into account when moving along
195        the compiled data. Specifically:
196    
197        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
198            length.
199    
200        (b) An item such as \pL+ within a repeated group could cause crashes or
201            loops.
202    
203        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
204            "reference to non-existent subpattern" error.
205    
206        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
207    
208    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
209        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
210    
211    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
212    
213    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
214        character were causing crashes (broken optimization).
215    
216    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
217        \p or \P) caused a compile-time loop.
218    
219    28. More problems have arisen in unanchored patterns when CRLF is a valid line
220        break. For example, the unstudied pattern [\r\n]A does not match the string
221        "\r\nA" because change 7.0/46 below moves the current point on by two
222        characters after failing to match at the start. However, the pattern \nA
223        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
224        the same is true. There doesn't seem any very clean way out of this, but
225        what I have chosen to do makes the common cases work: PCRE now takes note
226        of whether there can be an explicit match for \r or \n anywhere in the
227        pattern, and if so, 7.0/46 no longer applies. As part of this change,
228        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
229        pattern has explicit CR or LF references.
230    
231    29. Added (*CR) etc for changing newline setting at start of pattern.
232    
233    
234    Version 7.2 19-Jun-07
235    ---------------------
236    
237     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
238        which is apparently normally available under Windows.
239    
240     2. Re-jig the pcregrep tests with different newline settings in an attempt
241        to make them independent of the local environment's newline setting.
242    
243     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
244    
245     4. Some of the "internals" tests were previously cut out when the link size
246        was not 2, because the output contained actual offsets. The recent new
247        "Z" feature of pcretest means that these can be cut out, making the tests
248        usable with all link sizes.
249    
250     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
251        stack recursion. This gives a massive performance boost under BSD, but just
252        a small improvement under Linux. However, it saves one field in the frame
253        in all cases.
254    
255     6. Added more features from the forthcoming Perl 5.10:
256    
257        (a) (?-n) (where n is a string of digits) is a relative subroutine or
258            recursion call. It refers to the nth most recently opened parentheses.
259    
260        (b) (?+n) is also a relative subroutine call; it refers to the nth next
261            to be opened parentheses.
262    
263        (c) Conditions that refer to capturing parentheses can be specified
264            relatively, for example, (?(-2)... or (?(+3)...
265    
266        (d) \K resets the start of the current match so that everything before
267            is not part of it.
268    
269        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
270    
271        (f) \g{name} is another synonym - part of Perl 5.10's unification of
272            reference syntax.
273    
274        (g) (?| introduces a group in which the numbering of parentheses in each
275            alternative starts with the same number.
276    
277        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
278    
279     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
280        PCRE_INFO_JCHANGED.
281    
282     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
283        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
284        for detecting groups that can match an empty string.
285    
286     9. A pattern with a very large number of alternatives (more than several
287        hundred) was running out of internal workspace during the pre-compile
288        phase, where pcre_compile() figures out how much memory will be needed. A
289        bit of new cunning has reduced the workspace needed for groups with
290        alternatives. The 1000-alternative test pattern now uses 12 bytes of
291        workspace instead of running out of the 4096 that are available.
292    
293    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
294    
295    11. Applied patch from Google to remove an optimization that didn't quite work.
296        The report of the bug said:
297    
298          pcrecpp::RE("a*").FullMatch("aaa") matches, while
299          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
300          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
301    
302    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
303        it matched the wrong number of bytes.
304    
305    
306    Version 7.1 24-Apr-07
307    ---------------------
308    
309     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
310        that is more "standard", making use of automake and other Autotools. There
311        is some re-arrangement of the files and adjustment of comments consequent
312        on this.
313    
314     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
315        for recursive directory scanning broke on some systems because the files
316        are not scanned in any specific order and on different systems the order
317        was different. A call to "sort" has been inserted into RunGrepTest for the
318        approprate test as a short-term fix. In the longer term there may be an
319        alternative.
320    
321     3. I had an email from Eric Raymond about problems translating some of PCRE's
322        man pages to HTML (despite the fact that I distribute HTML pages, some
323        people do their own conversions for various reasons). The problems
324        concerned the use of low-level troff macros .br and .in. I have therefore
325        removed all such uses from the man pages (some were redundant, some could
326        be replaced by .nf/.fi pairs). The 132html script that I use to generate
327        HTML has been updated to handle .nf/.fi and to complain if it encounters
328        .br or .in.
329    
330     4. Updated comments in configure.ac that get placed in config.h.in and also
331        arranged for config.h to be included in the distribution, with the name
332        config.h.generic, for the benefit of those who have to compile without
333        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
334    
335     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
336        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
337        makevp.bat for the current PCRE, using the additional files
338        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
339    
340     6. A Windows user reported a minor discrepancy with test 2, which turned out
341        to be caused by a trailing space on an input line that had got lost in his
342        copy. The trailing space was an accident, so I've just removed it.
343    
344     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
345        that is needed.
346    
347     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
348        as "const" (a) because they are and (b) because it helps the PHP
349        maintainers who have recently made a script to detect big data structures
350        in the php code that should be moved to the .rodata section. I remembered
351        to update Builducptable as well, so it won't revert if ucptable.h is ever
352        re-created.
353    
354     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
355        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
356        order to be able to cut out the UTF-8 tables in the latter when UTF-8
357        support is not required. This saves 1.5-2K of code, which is important in
358        some applications.
359    
360        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
361        so as not to refer to the tables, even though these functions will never be
362        called when UTF-8 support is disabled. Otherwise there are problems with a
363        shared library.
364    
365    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
366    
367        (a) It was defining its arguments as char * instead of void *.
368    
369        (b) It was assuming that all moves were upwards in memory; this was true
370            a long time ago when I wrote it, but is no longer the case.
371    
372        The emulated memove() is provided for those environments that have neither
373        memmove() nor bcopy(). I didn't think anyone used it these days, but that
374        is clearly not the case, as these two bugs were recently reported.
375    
376    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
377        and Detrail to create the HTML documentation, the .txt form of the man
378        pages, and it removes trailing spaces from listed files. It also creates
379        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
380        case, it wraps all the #defines with #ifndefs. This script should be run
381        before "make dist".
382    
383    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
384        with Unicode property support.
385    
386        (a) For a maximizing quantifier, if the two different cases of the
387            character were of different lengths in their UTF-8 codings (there are
388            some cases like this - I found 11), and the matching function had to
389            back up over a mixture of the two cases, it incorrectly assumed they
390            were both the same length.
391    
392        (b) When PCRE was configured to use the heap rather than the stack for
393            recursion during matching, it was not correctly preserving the data for
394            the other case of a UTF-8 character when checking ahead for a match
395            while processing a minimizing repeat. If the check also involved
396            matching a wide character, but failed, corruption could cause an
397            erroneous result when trying to check for a repeat of the original
398            character.
399    
400    13. Some tidying changes to the testing mechanism:
401    
402        (a) The RunTest script now detects the internal link size and whether there
403            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
404            values substituted by "configure". (The RunGrepTest script already did
405            this for UTF-8.) The configure.ac script no longer substitutes the
406            relevant variables.
407    
408        (b) The debugging options /B and /D in pcretest show the compiled bytecode
409            with length and offset values. This means that the output is different
410            for different internal link sizes. Test 2 is skipped for link sizes
411            other than 2 because of this, bypassing the problem. Unfortunately,
412            there was also a test in test 3 (the locale tests) that used /B and
413            failed for link sizes other than 2. Rather than cut the whole test out,
414            I have added a new /Z option to pcretest that replaces the length and
415            offset values with spaces. This is now used to make test 3 independent
416            of link size. (Test 2 will be tidied up later.)
417    
418    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
419        segmentation fault instead of returning the appropriate error message.
420    
421    15. In multiline mode when the newline sequence was set to "any", the pattern
422        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
423        This doesn't seem right; it now treats the CRLF combination as the line
424        ending, and so does not match in that case. It's only a pattern such as ^$
425        that would hit this one: something like ^ABC$ would have failed after \r
426        and then tried again after \r\n.
427    
428    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
429        in an attempt to make files that differ only in their line terminators
430        compare equal. This works on Linux.
431    
432    17. Under certain error circumstances pcregrep might try to free random memory
433        as it exited. This is now fixed, thanks to valgrind.
434    
435    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
436        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
437        was because its rules for how to advance for /g after matching an empty
438        string at the end of a line did not allow for this case. They now check for
439        it specially.
440    
441    20. pcretest is supposed to handle patterns and data of any length, by
442        extending its buffers when necessary. It was getting this wrong when the
443        buffer for a data line had to be extended.
444    
445    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
446        CRLF as a newline sequence.
447    
448    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
449        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
450        I have nevertheless tidied it up.
451    
452    23. Added some casts to kill warnings from HP-UX ia64 compiler.
453    
454    24. Added a man page for pcre-config.
455    
456    
457    Version 7.0 19-Dec-06
458    ---------------------
459    
460     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
461        moving to gcc 4.1.1.
462    
463     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
464        sys/time.h, which is documented as needed for this function. It doesn't
465        seem to matter on Linux, but it showed up on some releases of OS X.
466    
467     3. It seems that there are systems where bytes whose values are greater than
468        127 match isprint() in the "C" locale. The "C" locale should be the
469        default when a C program starts up. In most systems, only ASCII printing
470        characters match isprint(). This difference caused the output from pcretest
471        to vary, making some of the tests fail. I have changed pcretest so that:
472    
473        (a) When it is outputting text in the compiled version of a pattern, bytes
474            other than 32-126 are always shown as hex escapes.
475    
476        (b) When it is outputting text that is a matched part of a subject string,
477            it does the same, unless a different locale has been set for the match
478            (using the /L modifier). In this case, it uses isprint() to decide.
479    
480     4. Fixed a major bug that caused incorrect computation of the amount of memory
481        required for a compiled pattern when options that changed within the
482        pattern affected the logic of the preliminary scan that determines the
483        length. The relevant options are -x, and -i in UTF-8 mode. The result was
484        that the computed length was too small. The symptoms of this bug were
485        either the PCRE error "internal error: code overflow" from pcre_compile(),
486        or a glibc crash with a message such as "pcretest: free(): invalid next
487        size (fast)". Examples of patterns that provoked this bug (shown in
488        pcretest format) are:
489    
490          /(?-x: )/x
491          /(?x)(?-x: \s*#\s*)/
492          /((?i)[\x{c0}])/8
493          /(?i:[\x{c0}])/8
494    
495        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
496        is now done differently.
497    
498     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
499        wrapper classes; (b) implement a new function in the C++ scanner that is
500        more efficient than the old way of doing things because it avoids levels of
501        recursion in the regex matching; (c) add a paragraph to the documentation
502        for the FullMatch() function.
503    
504     6. The escape sequence \n was being treated as whatever was defined as
505        "newline". Not only was this contrary to the documentation, which states
506        that \n is character 10 (hex 0A), but it also went horribly wrong when
507        "newline" was defined as CRLF. This has been fixed.
508    
509     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
510        was being set to -1 for the "end of line" case (supposedly a value that no
511        character can have). Though this value is never used (the check for end of
512        line is "zero bytes in current character"), it caused compiler complaints.
513        I've changed it to 0xffffffff.
514    
515     8. In pcre_version.c, the version string was being built by a sequence of
516        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
517        string (as it is for production releases) called a macro with an empty
518        argument. The C standard says the result of this is undefined. The gcc
519        compiler treats it as an empty string (which was what was wanted) but it is
520        reported that Visual C gives an error. The source has been hacked around to
521        avoid this problem.
522    
523     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
524        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
525        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
526        of them did).
527    
528    10. Originally, pcretest opened its input and output without "b"; then I was
529        told that "b" was needed in some environments, so it was added for release
530        5.0 to both the input and output. (It makes no difference on Unix-like
531        systems.) Later I was told that it is wrong for the input on Windows. I've
532        now abstracted the modes into two macros, to make it easier to fiddle with
533        them, and removed "b" from the input mode under Windows.
534    
535    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
536    
537    12. Added -help and --help to pcretest as an official way of being reminded
538        of the options.
539    
540    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
541        and pcrecpp.cc because they annoy compilers at high warning levels.
542    
543    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
544    
545    15. Fixed an occurrence of == in configure.ac that should have been = (shell
546        scripts are not C programs :-) and which was not noticed because it works
547        on Linux.
548    
549    16. pcretest is supposed to handle any length of pattern and data line (as one
550        line or as a continued sequence of lines) by extending its input buffer if
551        necessary. This feature was broken for very long pattern lines, leading to
552        a string of junk being passed to pcre_compile() if the pattern was longer
553        than about 50K.
554    
555    17. I have done a major re-factoring of the way pcre_compile() computes the
556        amount of memory needed for a compiled pattern. Previously, there was code
557        that made a preliminary scan of the pattern in order to do this. That was
558        OK when PCRE was new, but as the facilities have expanded, it has become
559        harder and harder to keep it in step with the real compile phase, and there
560        have been a number of bugs (see for example, 4 above). I have now found a
561        cunning way of running the real compile function in a "fake" mode that
562        enables it to compute how much memory it would need, while actually only
563        ever using a few hundred bytes of working memory and without too many
564        tests of the mode. This should make future maintenance and development
565        easier. A side effect of this work is that the limit of 200 on the nesting
566        depth of parentheses has been removed (though this was never a serious
567        limitation, I suspect). However, there is a downside: pcre_compile() now
568        runs more slowly than before (30% or more, depending on the pattern). I
569        hope this isn't a big issue. There is no effect on runtime performance.
570    
571    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
572        newline (only possible for the last line of a file) and it was a
573        pattern that set a locale (followed by /Lsomething), pcretest crashed.
574    
575    19. Added additional timing features to pcretest. (1) The -tm option now times
576        matching only, not compiling. (2) Both -t and -tm can be followed, as a
577        separate command line item, by a number that specifies the number of
578        repeats to use when timing. The default is 50000; this gives better
579        precision, but takes uncomfortably long for very large patterns.
580    
581    20. Extended pcre_study() to be more clever in cases where a branch of a
582        subpattern has no definite first character. For example, (a*|b*)[cd] would
583        previously give no result from pcre_study(). Now it recognizes that the
584        first character must be a, b, c, or d.
585    
586    21. There was an incorrect error "recursive call could loop indefinitely" if
587        a subpattern (or the entire pattern) that was being tested for matching an
588        empty string contained only one non-empty item after a nested subpattern.
589        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
590        incorrectly, because the \d was being skipped in the check.
591    
592    22. The pcretest program now has a new pattern option /B and a command line
593        option -b, which is equivalent to adding /B to every pattern. This causes
594        it to show the compiled bytecode, without the additional information that
595        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
596        is the same as /B/I).
597    
598    23. A new optimization is now able automatically to treat some sequences such
599        as a*b as a*+b. More specifically, if something simple (such as a character
600        or a simple class like \d) has an unlimited quantifier, and is followed by
601        something that cannot possibly match the quantified thing, the quantifier
602        is automatically "possessified".
603    
604    24. A recursive reference to a subpattern whose number was greater than 39
605        went wrong under certain circumstances in UTF-8 mode. This bug could also
606        have affected the operation of pcre_study().
607    
608    25. Realized that a little bit of performance could be had by replacing
609        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
610    
611    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
612    
613    27. Possessive quantifiers such as a++ were previously implemented by turning
614        them into atomic groups such as ($>a+). Now they have their own opcodes,
615        which improves performance. This includes the automatically created ones
616        from 23 above.
617    
618    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
619        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
620        the first matched character to be a colon. This applied both to named and
621        numbered groups.
622    
623    29. The ucpinternal.h header file was missing its idempotency #ifdef.
624    
625    30. I was sent a "project" file called libpcre.a.dev which I understand makes
626        building PCRE on Windows easier, so I have included it in the distribution.
627    
628    31. There is now a check in pcretest against a ridiculously large number being
629        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
630        loop, the loop is abandoned.
631    
632    32. Forward references to subpatterns in conditions such as (?(2)...) where
633        subpattern 2 is defined later cause pcre_compile() to search forwards in
634        the pattern for the relevant set of parentheses. This search went wrong
635        when there were unescaped parentheses in a character class, parentheses
636        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
637    
638    33. "Subroutine" calls and backreferences were previously restricted to
639        referencing subpatterns earlier in the regex. This restriction has now
640        been removed.
641    
642    34. Added a number of extra features that are going to be in Perl 5.10. On the
643        whole, these are just syntactic alternatives for features that PCRE had
644        previously implemented using the Python syntax or my own invention. The
645        other formats are all retained for compatibility.
646    
647        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
648            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
649            also .NET compatible.
650    
651        (b) A recursion or subroutine call to a named group can now be defined as
652            (?&name) as well as (?P>name).
653    
654        (c) A backreference to a named group can now be defined as \k<name> or
655            \k'name' as well as (?P=name). The new forms, as well as being in Perl
656            5.10, are also .NET compatible.
657    
658        (d) A conditional reference to a named group can now use the syntax
659            (?(<name>) or (?('name') as well as (?(name).
660    
661        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
662            groups (named and numbered) that are never evaluated inline, but can be
663            called as "subroutines" from elsewhere. In effect, the DEFINE condition
664            is always false. There may be only one alternative in such a group.
665    
666        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
667            as the simple (?(R). The condition is true only if the most recent
668            recursion is that of the given number or name. It does not search out
669            through the entire recursion stack.
670    
671        (g) The escape \gN or \g{N} has been added, where N is a positive or
672            negative number, specifying an absolute or relative reference.
673    
674    35. Tidied to get rid of some further signed/unsigned compiler warnings and
675        some "unreachable code" warnings.
676    
677    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
678        things, this adds five new scripts.
679    
680    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
681        There were also incompatibilities regarding the handling of \Q..\E inside
682        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
683        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
684    
685    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
686        matches an empty string, and forcibly breaks the loop. There were bugs in
687        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
688        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
689        separate and independent bugs (that affected different cases) have been
690        fixed.
691    
692    39. Refactored the code to abolish the use of different opcodes for small
693        capturing bracket numbers. This is a tidy that I avoided doing when I
694        removed the limit on the number of capturing brackets for 3.5 back in 2001.
695        The new approach is not only tidier, it makes it possible to reduce the
696        memory needed to fix the previous bug (38).
697    
698    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
699        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
700        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
701        mode.
702    
703    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
704        report.
705    
706    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
707        copy construction and assignment in the C++ wrapper.
708    
709    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
710        couple of bugs that could have given wrong results in the "--newline=crlf"
711        case.
712    
713    44. Added a number of casts and did some reorganization of signed/unsigned int
714        variables following suggestions from Dair Grant. Also renamed the variable
715        "this" as "item" because it is a C++ keyword.
716    
717    45. Arranged for dftables to add
718    
719          #include "pcre_internal.h"
720    
721        to pcre_chartables.c because without it, gcc 4.x may remove the array
722        definition from the final binary if PCRE is built into a static library and
723        dead code stripping is activated.
724    
725    46. For an unanchored pattern, if a match attempt fails at the start of a
726        newline sequence, and the newline setting is CRLF or ANY, and the next two
727        characters are CRLF, advance by two characters instead of one.
728    
729    
730    Version 6.7 04-Jul-06
731    ---------------------
732    
733     1. In order to handle tests when input lines are enormously long, pcretest has
734        been re-factored so that it automatically extends its buffers when
735        necessary. The code is crude, but this _is_ just a test program. The
736        default size has been increased from 32K to 50K.
737    
738     2. The code in pcre_study() was using the value of the re argument before
739        testing it for NULL. (Of course, in any sensible call of the function, it
740        won't be NULL.)
741    
742     3. The memmove() emulation function in pcre_internal.h, which is used on
743        systems that lack both memmove() and bcopy() - that is, hardly ever -
744        was missing a "static" storage class specifier.
745    
746     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
747        containing an extended class (one that cannot be represented by a bitmap
748        because it contains high-valued characters or Unicode property items, e.g.
749        [\pZ]). Almost always one would set UTF-8 mode when processing such a
750        pattern, but PCRE should not loop if you do not (it no longer does).
751        [Detail: two cases were found: (a) a repeated subpattern containing an
752        extended class; (b) a recursive reference to a subpattern that followed a
753        previous extended class. It wasn't skipping over the extended class
754        correctly when UTF-8 mode was not set.]
755    
756     5. A negated single-character class was not being recognized as fixed-length
757        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
758        compile error "lookbehind assertion is not fixed length".
759    
760     6. The RunPerlTest auxiliary script was showing an unexpected difference
761        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
762        write a Perl script that can interpret lines of an input file either as
763        byte characters or as UTF-8, which is what "perltest" was being required to
764        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
765        can't do is switch easily at run time between having the "use utf8;" pragma
766        or not. In the end, I fudged it by using the RunPerlTest script to insert
767        "use utf8;" explicitly for the UTF-8 tests.
768    
769     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
770        the end of the subject string, contrary to the documentation and to what
771        Perl does. This was true of both matching functions. Now it matches only at
772        the start of the subject and immediately after *internal* newlines.
773    
774     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
775        a pointer to an int instead of a pointer to an unsigned long int. This
776        caused problems on 64-bit systems.
777    
778     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
779        instance of the 'standard' template library not being so standard".
780    
781    10. There was no check on the number of named subpatterns nor the maximum
782        length of a subpattern name. The product of these values is used to compute
783        the size of the memory block for a compiled pattern. By supplying a very
784        long subpattern name and a large number of named subpatterns, the size
785        computation could be caused to overflow. This is now prevented by limiting
786        the length of names to 32 characters, and the number of named subpatterns
787        to 10,000.
788    
789    11. Subpatterns that are repeated with specific counts have to be replicated in
790        the compiled pattern. The size of memory for this was computed from the
791        length of the subpattern and the repeat count. The latter is limited to
792        65535, but there was no limit on the former, meaning that integer overflow
793        could in principle occur. The compiled length of a repeated subpattern is
794        now limited to 30,000 bytes in order to prevent this.
795    
796    12. Added the optional facility to have named substrings with the same name.
797    
798    13. Added the ability to use a named substring as a condition, using the
799        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
800        are numbers (not recommended). Forward references are permitted.
801    
802    14. Added forward references in named backreferences (if you see what I mean).
803    
804    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
805        pattern could run off the end of the subject. For example, the pattern
806        "(?s)(.{1,5})"8 did this with the subject "ab".
807    
808    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
809        PCRE_CASELESS was set when matching characters that were quantified with ?
810        or *.
811    
812    17. A character class other than a single negated character that had a minimum
813        but no maximum quantifier - for example [ab]{6,} - was not handled
814        correctly by pce_dfa_exec(). It would match only one character.
815    
816    18. A valid (though odd) pattern that looked like a POSIX character
817        class but used an invalid character after [ (for example [[,abc,]]) caused
818        pcre_compile() to give the error "Failed: internal error: code overflow" or
819        in some cases to crash with a glibc free() error. This could even happen if
820        the pattern terminated after [[ but there just happened to be a sequence of
821        letters, a binary zero, and a closing ] in the memory that followed.
822    
823    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
824        over the years. Originally (before any Unicode support), just the bottom 8
825        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
826        output from "man perlunicode" includes this:
827    
828          The regular expression compiler produces polymorphic opcodes.  That
829          is, the pattern adapts to the data and automatically switches to
830          the Unicode character scheme when presented with Unicode data--or
831          instead uses a traditional byte scheme when presented with byte
832          data.
833    
834        Sadly, a wide octal escape does not cause a switch, and in a string with
835        no other multibyte characters, these octal escapes are treated as before.
836        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
837        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
838        Unicode string.
839    
840        I have not perpetrated such confusion in PCRE. Up till now, it took just
841        the bottom 8 bits, as in old Perl. I have now made octal escapes with
842        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
843        translate to the appropriate multibyte character.
844    
845    29. Applied some refactoring to reduce the number of warnings from Microsoft
846        and Borland compilers. This has included removing the fudge introduced
847        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
848        a warning about an unused variable.
849    
850    21. PCRE has not included VT (character 0x0b) in the set of whitespace
851        characters since release 4.0, because Perl (from release 5.004) does not.
852        [Or at least, is documented not to: some releases seem to be in conflict
853        with the documentation.] However, when a pattern was studied with
854        pcre_study() and all its branches started with \s, PCRE still included VT
855        as a possible starting character. Of course, this did no harm; it just
856        caused an unnecessary match attempt.
857    
858    22. Removed a now-redundant internal flag bit that recorded the fact that case
859        dependency changed within the pattern. This was once needed for "required
860        byte" processing, but is no longer used. This recovers a now-scarce options
861        bit. Also moved the least significant internal flag bit to the most-
862        significant bit of the word, which was not previously used (hangover from
863        the days when it was an int rather than a uint) to free up another bit for
864        the future.
865    
866    23. Added support for CRLF line endings as well as CR and LF. As well as the
867        default being selectable at build time, it can now be changed at runtime
868        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
869        specify that it is scanning data with non-default line endings.
870    
871    24. Changed the definition of CXXLINK to make it agree with the definition of
872        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
873    
874    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
875        recursions. This makes a big different to stack usage for some patterns.
876    
877    26. If a subpattern containing a named recursion or subroutine reference such
878        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
879        the space required for the compiled pattern went wrong and gave too small a
880        value. Depending on the environment, this could lead to "Failed: internal
881        error: code overflow at offset 49" or "glibc detected double free or
882        corruption" errors.
883    
884    27. Applied patches from Google (a) to support the new newline modes and (b) to
885        advance over multibyte UTF-8 characters in GlobalReplace.
886    
887    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
888        difference for some implementation of PCRE in some Windows version.
889    
890    29. Added some extra testing facilities to pcretest:
891    
892        \q<number>   in a data line sets the "match limit" value
893        \Q<number>   in a data line sets the "match recursion limt" value
894        -S <number>  sets the stack size, where <number> is in megabytes
895    
896        The -S option isn't available for Windows.
897    
898    
899    Version 6.6 06-Feb-06
900    ---------------------
901    
902     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
903        in pcreposix.h. I have copied the definition from pcre.h.
904    
905     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
906        because pcre.h is no longer a built file.
907    
908     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
909        not normally included in the compiled code.
910    
911    
912    Version 6.5 01-Feb-06
913    ---------------------
914    
915     1. When using the partial match feature with pcre_dfa_exec(), it was not
916        anchoring the second and subsequent partial matches at the new starting
917        point. This could lead to incorrect results. For example, with the pattern
918        /1234/, partially matching against "123" and then "a4" gave a match.
919    
920     2. Changes to pcregrep:
921    
922        (a) All non-match returns from pcre_exec() were being treated as failures
923            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
924            error message is output. Some extra information is given for the
925            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
926            probably the only errors that are likely to be caused by users (by
927            specifying a regex that has nested indefinite repeats, for instance).
928            If there are more than 20 of these errors, pcregrep is abandoned.
929    
930        (b) A binary zero was treated as data while matching, but terminated the
931            output line if it was written out. This has been fixed: binary zeroes
932            are now no different to any other data bytes.
933    
934        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
935            used to set a locale for matching. The --locale=xxxx long option has
936            been added (no short equivalent) to specify a locale explicitly on the
937            pcregrep command, overriding the environment variables.
938    
939        (d) When -B was used with -n, some line numbers in the output were one less
940            than they should have been.
941    
942        (e) Added the -o (--only-matching) option.
943    
944        (f) If -A or -C was used with -c (count only), some lines of context were
945            accidentally printed for the final match.
946    
947        (g) Added the -H (--with-filename) option.
948    
949        (h) The combination of options -rh failed to suppress file names for files
950            that were found from directory arguments.
951    
952        (i) Added the -D (--devices) and -d (--directories) options.
953    
954        (j) Added the -F (--fixed-strings) option.
955    
956        (k) Allow "-" to be used as a file name for -f as well as for a data file.
957    
958        (l) Added the --colo(u)r option.
959    
960        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
961            is not present by default.
962    
963     3. A nasty bug was discovered in the handling of recursive patterns, that is,
964        items such as (?R) or (?1), when the recursion could match a number of
965        alternatives. If it matched one of the alternatives, but subsequently,
966        outside the recursion, there was a failure, the code tried to back up into
967        the recursion. However, because of the way PCRE is implemented, this is not
968        possible, and the result was an incorrect result from the match.
969    
970        In order to prevent this happening, the specification of recursion has
971        been changed so that all such subpatterns are automatically treated as
972        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
973    
974     4. I had overlooked the fact that, in some locales, there are characters for
975        which isalpha() is true but neither isupper() nor islower() are true. In
976        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
977        and ordfeminine) are like this. This affected the treatment of \w and \W
978        when they appeared in character classes, but not when they appeared outside
979        a character class. The bit map for "word" characters is now created
980        separately from the results of isalnum() instead of just taking it from the
981        upper, lower, and digit maps. (Plus the underscore character, of course.)
982    
983     5. The above bug also affected the handling of POSIX character classes such as
984        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
985        permanent tables. Instead, the bit maps for such a class were previously
986        created as the appropriate unions of the upper, lower, and digit bitmaps.
987        Now they are created by subtraction from the [[:word:]] class, which has
988        its own bitmap.
989    
990     6. The [[:blank:]] character class matches horizontal, but not vertical space.
991        It is created by subtracting the vertical space characters (\x09, \x0a,
992        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
993        subtraction was done in the overall bitmap for a character class, meaning
994        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
995        be recognized. This bug has been fixed.
996    
997     7. Patches from the folks at Google:
998    
999          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1000          real life, but is still worth protecting against".
1001    
1002          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1003          regular expressions".
1004    
1005          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1006          have it.
1007    
1008          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1009          "configure" and the latter not, in order to fix a problem somebody had
1010          with compiling the Arg class on HP-UX.
1011    
1012          (e) Improve the error-handling of the C++ wrapper a little bit.
1013    
1014          (f) New tests for checking recursion limiting.
1015    
1016     8. The pcre_memmove() function, which is used only if the environment does not
1017        have a standard memmove() function (and is therefore rarely compiled),
1018        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1019        returning a result (though PCRE never actually uses the result).
1020    
1021     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1022        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1023        returned instead of calling malloc() with an overflowing number that would
1024        most likely cause subsequent chaos.
1025    
1026    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1027    
1028    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1029        with this option is matched, the nmatch and pmatch options of regexec() are
1030        ignored.
1031    
1032    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1033        provided in case anyone wants to the the POSIX interface with UTF-8
1034        strings.
1035    
1036    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1037        C++ linking (needed for some HP-UX environments).
1038    
1039    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1040        (unused parameter) and in the pcre_printint() function (omitted "default"
1041        switch label when the default is to do nothing).
1042    
1043    15. Added some code to make it possible, when PCRE is compiled as a C++
1044        library, to replace subject pointers for pcre_exec() with a smart pointer
1045        class, thus making it possible to process discontinuous strings.
1046    
1047    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1048        much the same function. They were added by different people who were trying
1049        to make PCRE easy to compile on non-Unix systems. It has been suggested
1050        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1051        for compiling on Windows systems. I have therefore replaced it with
1052        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1053        defaults to "extern" for C or "extern C" for C++, which works fine on
1054        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1055        SCOPE with something explicit in config.h. In addition:
1056    
1057        (a) pcreposix.h still had just "extern" instead of either of these macros;
1058            I have replaced it with PCRE_DATA_SCOPE.
1059    
1060        (b) Functions such as _pcre_xclass(), which are internal to the library,
1061            but external in the C sense, all had PCRE_EXPORT in their definitions.
1062            This is apparently wrong for the Windows case, so I have removed it.
1063            (It makes no difference on Unix-like systems.)
1064    
1065    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1066        of recursive calls to match(). This is different to MATCH_LIMIT because
1067        that limits the total number of calls to match(), not all of which increase
1068        the depth of recursion. Limiting the recursion depth limits the amount of
1069        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1070        when PCRE is compiled, and changed at run time. A patch from Google adds
1071        this functionality to the C++ interface.
1072    
1073    18. Changes to the handling of Unicode character properties:
1074    
1075        (a) Updated the table to Unicode 4.1.0.
1076    
1077        (b) Recognize characters that are not in the table as "Cn" (undefined).
1078    
1079        (c) I revised the way the table is implemented to a much improved format
1080            which includes recognition of ranges. It now supports the ranges that
1081            are defined in UnicodeData.txt, and it also amalgamates other
1082            characters into ranges. This has reduced the number of entries in the
1083            table from around 16,000 to around 3,000, thus reducing its size
1084            considerably. I realized I did not need to use a tree structure after
1085            all - a binary chop search is just as efficient. Having reduced the
1086            number of entries, I extended their size from 6 bytes to 8 bytes to
1087            allow for more data.
1088    
1089        (d) Added support for Unicode script names via properties such as \p{Han}.
1090    
1091    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1092        matching that character.
1093    
1094    20. When matching a repeated Unicode property with a minimum greater than zero,
1095        (for example \pL{2,}), PCRE could look past the end of the subject if it
1096        reached it while seeking the minimum number of characters. This could
1097        happen only if some of the characters were more than one byte long, because
1098        there is a check for at least the minimum number of bytes.
1099    
1100    21. Refactored the implementation of \p and \P so as to be more general, to
1101        allow for more different types of property in future. This has changed the
1102        compiled form incompatibly. Anybody with saved compiled patterns that use
1103        \p or \P will have to recompile them.
1104    
1105    22. Added "Any" and "L&" to the supported property types.
1106    
1107    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1108        but give a compile time error if the value is greater than 0xff.
1109    
1110    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1111        accidentally not being installed or uninstalled.
1112    
1113    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1114        made were to insert the current release number. This seemed silly, because
1115        it made things harder for people building PCRE on systems that don't run
1116        "configure". I have turned pcre.h into a distributed file, no longer built
1117        by "configure", with the version identification directly included. There is
1118        no longer a pcre.h.in file.
1119    
1120        However, this change necessitated a change to the pcre-config script as
1121        well. It is built from pcre-config.in, and one of the substitutions was the
1122        release number. I have updated configure.ac so that ./configure now finds
1123        the release number by grepping pcre.h.
1124    
1125    26. Added the ability to run the tests under valgrind.
1126    
1127    
1128    Version 6.4 05-Sep-05
1129    ---------------------
1130    
1131     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1132        "--" to be printed when multiple files were scanned, even when none of the
1133        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1134        consider it to be a bug, and have restored the previous behaviour.
1135    
1136     2. A couple of code tidies to get rid of compiler warnings.
1137    
1138     3. The pcretest program used to cheat by referring to symbols in the library
1139        whose names begin with _pcre_. These are internal symbols that are not
1140        really supposed to be visible externally, and in some environments it is
1141        possible to suppress them. The cheating is now confined to including
1142        certain files from the library's source, which is a bit cleaner.
1143    
1144     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1145        file's purpose clearer.
1146    
1147     5. Reorganized pcre_ucp_findchar().
1148    
1149    
1150    Version 6.3 15-Aug-05
1151    ---------------------
1152    
1153     1. The file libpcre.pc.in did not have general read permission in the tarball.
1154    
1155     2. There were some problems when building without C++ support:
1156    
1157        (a) If C++ support was not built, "make install" and "make test" still
1158            tried to test it.
1159    
1160        (b) There were problems when the value of CXX was explicitly set. Some
1161            changes have been made to try to fix these, and ...
1162    
1163        (c) --disable-cpp can now be used to explicitly disable C++ support.
1164    
1165        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1166            backslash in a target when C++ was disabled. This confuses some
1167            versions of "make", apparently. Using an intermediate variable solves
1168            this. (Same for CPP_LOBJ.)
1169    
1170     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1171        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1172        necessary on certain architectures.
1173    
1174     4. Added a setting of -export-symbols-regex to the link command to remove
1175        those symbols that are exported in the C sense, but actually are local
1176        within the library, and not documented. Their names all begin with
1177        "_pcre_". This is not a perfect job, because (a) we have to except some
1178        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1179        available (and never for static libraries). I have made a note to try to
1180        find a way round (a) in the future.
1181    
1182    
1183    Version 6.2 01-Aug-05
1184    ---------------------
1185    
1186     1. There was no test for integer overflow of quantifier values. A construction
1187        such as {1111111111111111} would give undefined results. What is worse, if
1188        a minimum quantifier for a parenthesized subpattern overflowed and became
1189        negative, the calculation of the memory size went wrong. This could have
1190        led to memory overwriting.
1191    
1192     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1193    
1194     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1195        operating environments where this matters.
1196    
1197     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1198        PCRE options from within the C++ wrapper.
1199    
1200     5. Named capturing subpatterns were not being correctly counted when a pattern
1201        was compiled. This caused two problems: (a) If there were more than 100
1202        such subpatterns, the calculation of the memory needed for the whole
1203        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1204        back references of the form \12, where the number was greater than 9, were
1205        not recognized as back references, even though there were sufficient
1206        previous subpatterns.
1207    
1208     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1209        versions of gcc, e.g. 2.95.4.
1210    
1211    
1212    Version 6.1 21-Jun-05
1213    ---------------------
1214    
1215     1. There was one reference to the variable "posix" in pcretest.c that was not
1216        surrounded by "#if !defined NOPOSIX".
1217    
1218     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1219        the cross-check on the old pcre_info() function, for the benefit of the
1220        cut-down version of PCRE that is currently imported into Exim.
1221    
1222     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1223        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1224        patterns that start (?i) but I don't think that matters. The use of (?i) is
1225        just an example; this all applies to the other options as well.
1226    
1227     4. Since libtool seems to echo the compile commands it is issuing, the output
1228        from "make" can be reduced a bit by putting "@" in front of each libtool
1229        compile command.
1230    
1231     5. Patch from the folks at Google for configure.in to be a bit more thorough
1232        in checking for a suitable C++ installation before trying to compile the
1233        C++ stuff. This should fix a reported problem when a compiler was present,
1234        but no suitable headers.
1235    
1236     6. The man pages all had just "PCRE" as their title. I have changed them to
1237        be the relevant file name. I have also arranged that these names are
1238        retained in the file doc/pcre.txt, which is a concatenation in text format
1239        of all the man pages except the little individual ones for each function.
1240    
1241     7. The NON-UNIX-USE file had not been updated for the different set of source
1242        files that come with release 6. I also added a few comments about the C++
1243        wrapper.
1244    
1245    
1246    Version 6.0 07-Jun-05
1247    ---------------------
1248    
1249     1. Some minor internal re-organization to help with my DFA experiments.
1250    
1251     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1252        didn't matter for the library itself when fully configured, but did matter
1253        when compiling without UCP support, or within Exim, where the ucp files are
1254        not imported.
1255    
1256     3. Refactoring of the library code to split up the various functions into
1257        different source modules. The addition of the new DFA matching code (see
1258        below) to a single monolithic source would have made it really too
1259        unwieldy, quite apart from causing all the code to be include in a
1260        statically linked application, when only some functions are used. This is
1261        relevant even without the DFA addition now that patterns can be compiled in
1262        one application and matched in another.
1263    
1264        The downside of splitting up is that there have to be some external
1265        functions and data tables that are used internally in different modules of
1266        the library but which are not part of the API. These have all had their
1267        names changed to start with "_pcre_" so that they are unlikely to clash
1268        with other external names.
1269    
1270     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1271        a different (DFA) algorithm. Although it is slower than the original
1272        function, it does have some advantages for certain types of matching
1273        problem.
1274    
1275     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1276        including restarting after a partial match.
1277    
1278     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1279        defined when compiling for Windows was sent to me. I have put it into the
1280        code, though I have no means of testing or verifying it.
1281    
1282     7. Added the pcre_refcount() auxiliary function.
1283    
1284     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1285        match before or at the first newline in the subject string. In pcretest,
1286        the /f option on a pattern can be used to set this.
1287    
1288     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1289        would behave wrongly. This has been present in PCRE since release 4.0.
1290    
1291    10. A number of changes to the pcregrep command:
1292    
1293        (a) Refactored how -x works; insert ^(...)$ instead of setting
1294            PCRE_ANCHORED and checking the length, in preparation for adding
1295            something similar for -w.
1296    
1297        (b) Added the -w (match as a word) option.
1298    
1299        (c) Refactored the way lines are read and buffered so as to have more
1300            than one at a time available.
1301    
1302        (d) Implemented a pcregrep test script.
1303    
1304        (e) Added the -M (multiline match) option. This allows patterns to match
1305            over several lines of the subject. The buffering ensures that at least
1306            8K, or the rest of the document (whichever is the shorter) is available
1307            for matching (and similarly the previous 8K for lookbehind assertions).
1308    
1309        (f) Changed the --help output so that it now says
1310    
1311              -w, --word-regex(p)
1312    
1313            instead of two lines, one with "regex" and the other with "regexp"
1314            because that confused at least one person since the short forms are the
1315            same. (This required a bit of code, as the output is generated
1316            automatically from a table. It wasn't just a text change.)
1317    
1318        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1319            option but starts with a hyphen. Could be a pattern or a path name
1320            starting with a hyphen, for instance.
1321    
1322        (h) "-" can be given as a file name to represent stdin.
1323    
1324        (i) When file names are being printed, "(standard input)" is used for
1325            the standard input, for compatibility with GNU grep. Previously
1326            "<stdin>" was used.
1327    
1328        (j) The option --label=xxx can be used to supply a name to be used for
1329            stdin when file names are being printed. There is no short form.
1330    
1331        (k) Re-factored the options decoding logic because we are going to add
1332            two more options that take data. Such options can now be given in four
1333            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1334    
1335        (l) Added the -A, -B, and -C options for requesting that lines of context
1336            around matches be printed.
1337    
1338        (m) Added the -L option to print the names of files that do not contain
1339            any matching lines, that is, the complement of -l.
1340    
1341        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1342            continue to scan other files.
1343    
1344        (o) The -s option was incorrectly implemented. For compatibility with other
1345            greps, it now suppresses the error message for a non-existent or non-
1346            accessible file (but not the return code). There is a new option called
1347            -q that suppresses the output of matching lines, which was what -s was
1348            previously doing.
1349    
1350        (p) Added --include and --exclude options to specify files for inclusion
1351            and exclusion when recursing.
1352    
1353    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1354        Hopefully, it now does.
1355    
1356    12. Missing cast in pcre_study().
1357    
1358    13. Added an "uninstall" target to the makefile.
1359    
1360    14. Replaced "extern" in the function prototypes in Makefile.in with
1361        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1362        world, but is set differently for Windows.
1363    
1364    15. Added a second compiling function called pcre_compile2(). The only
1365        difference is that it has an extra argument, which is a pointer to an
1366        integer error code. When there is a compile-time failure, this is set
1367        non-zero, in addition to the error test pointer being set to point to an
1368        error message. The new argument may be NULL if no error number is required
1369        (but then you may as well call pcre_compile(), which is now just a
1370        wrapper). This facility is provided because some applications need a
1371        numeric error indication, but it has also enabled me to tidy up the way
1372        compile-time errors are handled in the POSIX wrapper.
1373    
1374    16. Added VPATH=.libs to the makefile; this should help when building with one
1375        prefix path and installing with another. (Or so I'm told by someone who
1376        knows more about this stuff than I do.)
1377    
1378    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1379        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1380        match everything, including newlines. This is not POSIX-compatible, but
1381        somebody wanted the feature. From pcretest it can be activated by using
1382        both the P and the s flags.
1383    
1384    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1385    
1386    19. libpcre.pc was being incorrectly installed as executable.
1387    
1388    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1389        it now also looks for '\r' so that it will work unmodified on Windows.
1390    
1391    21. Added Google's contributed C++ wrapper to the distribution.
1392    
1393    22. Added some untidy missing memory free() calls in pcretest, to keep
1394        Electric Fence happy when testing.
1395    
1396    
1397    
1398    Version 5.0 13-Sep-04
1399    ---------------------
1400    
1401     1. Internal change: literal characters are no longer packed up into items
1402        containing multiple characters in a single byte-string. Each character
1403        is now matched using a separate opcode. However, there may be more than one
1404        byte in the character in UTF-8 mode.
1405    
1406     2. The pcre_callout_block structure has two new fields: pattern_position and
1407        next_item_length. These contain the offset in the pattern to the next match
1408        item, and its length, respectively.
1409    
1410     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1411        insertion of callouts before each pattern item. Added the /C option to
1412        pcretest to make use of this.
1413    
1414     4. On the advice of a Windows user, the lines
1415    
1416          #if defined(_WIN32) || defined(WIN32)
1417          _setmode( _fileno( stdout ), 0x8000 );
1418          #endif  /* defined(_WIN32) || defined(WIN32) */
1419    
1420        have been added to the source of pcretest. This apparently does useful
1421        magic in relation to line terminators.
1422    
1423     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1424        for the benefit of those environments where the "b" makes a difference.
1425    
1426     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1427        to know about it. I have put a hack into configure.in that adds in code
1428        to set GCC=yes if CC=icc. This seems to end up at a point in the
1429        generated configure script that is early enough to affect the setting of
1430        compiler options, which is what is needed, but I have no means of testing
1431        whether it really works. (The user who reported this had patched the
1432        generated configure script, which of course I cannot do.)
1433    
1434        LATER: After change 22 below (new libtool files), the configure script
1435        seems to know about icc (and also ecc). Therefore, I have commented out
1436        this hack in configure.in.
1437    
1438     7. Added support for pkg-config (2 patches were sent in).
1439    
1440     8. Negated POSIX character classes that used a combination of internal tables
1441        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1442        [[:^ascii]]. Typically, they would match almost any characters. The other
1443        POSIX classes were not broken in this way.
1444    
1445     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1446        to find the match, as PCRE was deluded into thinking that the match had to
1447        start at the start point or following a newline. The same bug applied to
1448        patterns with negative forward assertions or any backward assertions
1449        preceding ".*" at the start, unless the pattern required a fixed first
1450        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1451    
1452    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1453        starting at the last subject character, bytes beyond the end of the subject
1454        string were read.
1455    
1456    11. Renamed the variable "class" as "classbits" to make life easier for C++
1457        users. (Previously there was a macro definition, but it apparently wasn't
1458        enough.)
1459    
1460    12. Added the new field "tables" to the extra data so that tables can be passed
1461        in at exec time, or the internal tables can be re-selected. This allows
1462        a compiled regex to be saved and re-used at a later time by a different
1463        program that might have everything at different addresses.
1464    
1465    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1466        -R library as well as a -L library.
1467    
1468    14. The debugging options of pcretest (-d on the command line or D on a
1469        pattern) showed incorrect output for anything following an extended class
1470        that contained multibyte characters and which was followed by a quantifier.
1471    
1472    15. Added optional support for general category Unicode character properties
1473        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1474        support. It adds about 90K to the size of the library. The meanings of the
1475        inbuilt class escapes such as \d and \s have NOT been changed.
1476    
1477    16. Updated pcredemo.c to include calls to free() to release the memory for the
1478        compiled pattern.
1479    
1480    17. The generated file chartables.c was being created in the source directory
1481        instead of in the building directory. This caused the build to fail if the
1482        source directory was different from the building directory, and was
1483        read-only.
1484    
1485    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1486        file. No doubt somebody will tell me if they don't make sense... Also added
1487        Dan Mooney's comments about building on OpenVMS.
1488    
1489    19. Added support for partial matching via the PCRE_PARTIAL option for
1490        pcre_exec() and the \P data escape in pcretest.
1491    
1492    20. Extended pcretest with 3 new pattern features:
1493    
1494        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1495              write the compiled pattern to the file whose name is "rest-of-line".
1496              This is a straight binary dump of the data, with the saved pointer to
1497              the character tables forced to be NULL. The study data, if any, is
1498              written too. After writing, pcretest reads a new pattern.
1499    
1500        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1501              compiled pattern from the given file. There must not be any
1502              occurrences of "<" in the file name (pretty unlikely); if there are,
1503              pcretest will instead treat the initial "<" as a pattern delimiter.
1504              After reading in the pattern, pcretest goes on to read data lines as
1505              usual.
1506    
1507        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1508              and 16-bit fields in a compiled pattern, to simulate a pattern that
1509              was compiled on a host of opposite endianness.
1510    
1511    21. The pcre-exec() function can now cope with patterns that were compiled on
1512        hosts of opposite endianness, with this restriction:
1513    
1514          As for any compiled expression that is saved and used later, the tables
1515          pointer field cannot be preserved; the extra_data field in the arguments
1516          to pcre_exec() should be used to pass in a tables address if a value
1517          other than the default internal tables were used at compile time.
1518    
1519    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1520        now diagnosed as an error. Previously, most of the time, a negative number
1521        would have been treated as zero, but if in addition "ovector" was passed as
1522        NULL, a crash could occur.
1523    
1524    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1525        new versions from the libtool 1.5 distribution (the last one is a copy of
1526        a file called libtool.m4). This seems to have fixed the need to patch
1527        "configure" to support Darwin 1.3 (which I used to do). However, I still
1528        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1529        workstation).
1530    
1531    24. Changed the PCRE licence to be the more standard "BSD" licence.
1532    
1533    
1534    Version 4.5 01-Dec-03
1535    ---------------------
1536    
1537     1. There has been some re-arrangement of the code for the match() function so
1538        that it can be compiled in a version that does not call itself recursively.
1539        Instead, it keeps those local variables that need separate instances for
1540        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1541        needs to "recurse". Keeping track of where control must go is done by means
1542        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1543        hide most of the details from the main code, and operates only if
1544        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1545        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1546        operating.
1547    
1548        To make it easier for callers to provide specially tailored get/free
1549        functions for this usage, two new functions, pcre_stack_malloc, and
1550        pcre_stack_free, are used. They are always called in strict stacking order,
1551        and the size of block requested is always the same.
1552    
1553        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1554        PCRE has been compiled to use the stack or the heap for recursion. The
1555        -C option of pcretest uses this to show which version is compiled.
1556    
1557        A new data escape \S, is added to pcretest; it causes the amounts of store
1558        obtained and freed by both kinds of malloc/free at match time to be added
1559        to the output.
1560    
1561     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1562        what's available on my current Linux desktop machine.
1563    
1564     3. When matching a UTF-8 string, the test for a valid string at the start has
1565        been extended. If start_offset is not zero, PCRE now checks that it points
1566        to a byte that is the start of a UTF-8 character. If not, it returns
1567        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1568        this is necessary because there may be backward assertions in the pattern.
1569        When matching the same subject several times, it may save resources to use
1570        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1571    
1572     4. The code for checking the validity of UTF-8 strings has been tightened so
1573        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1574        containing "overlong sequences".
1575    
1576     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1577        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1578        should have been "&", but it just so happened that all the cases this let
1579        through by mistake were picked up later in the function.
1580    
1581     6. I had used a variable called "isblank" - this is a C99 function, causing
1582        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1583    
1584     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1585        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1586        so the version is shown; (c) stop "make test" echoing "./RunTest".
1587    
1588     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1589    
1590     9. The prototype for memmove() for systems that don't have it was using
1591        size_t, but the inclusion of the header that defines size_t was later. I've
1592        moved the #includes for the C headers earlier to avoid this.
1593    
1594    10. Added some adjustments to the code to make it easier to compiler on certain
1595        special systems:
1596    
1597          (a) Some "const" qualifiers were missing.
1598          (b) Added the macro EXPORT before all exported functions; by default this
1599              is defined to be empty.
1600          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1601              that it reads its output file name as an argument instead of writing
1602              to the standard output and assuming this can be redirected.
1603    
1604    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1605        class containing characters with values greater than 255, PCRE compilation
1606        went into a loop.
1607    
1608    12. A recursive reference to a subpattern that was within another subpattern
1609        that had a minimum quantifier of zero caused PCRE to crash. For example,
1610        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1611        recursion. If the recursively-called subpattern itself had a zero repeat,
1612        that was OK.
1613    
1614    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1615        buffer into which it was copied (for escape processing) was still set at
1616        1024, so long lines caused crashes.
1617    
1618    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1619        "internal error: code overflow...". This applied to any character class
1620        that was followed by a possessive quantifier.
1621    
1622    15. Modified the Makefile to add libpcre.la as a prerequisite for
1623        libpcreposix.la because I was told this is needed for a parallel build to
1624        work.
1625    
1626    16. If a pattern that contained .* following optional items at the start was
1627        studied, the wrong optimizing data was generated, leading to matching
1628        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1629        matching string must start with a or b or c. The correct conclusion for
1630        this pattern is that a match can start with any character.
1631    
1632    
1633    Version 4.4 13-Aug-03
1634    ---------------------
1635    
1636     1. In UTF-8 mode, a character class containing characters with values between
1637        127 and 255 was not handled correctly if the compiled pattern was studied.
1638        In fixing this, I have also improved the studying algorithm for such
1639        classes (slightly).
1640    
1641     2. Three internal functions had redundant arguments passed to them. Removal
1642        might give a very teeny performance improvement.
1643    
1644     3. Documentation bug: the value of the capture_top field in a callout is *one
1645        more than* the number of the hightest numbered captured substring.
1646    
1647     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1648        in incorrectly linking with a previously installed version. They now link
1649        explicitly with libpcre.la.
1650    
1651     5. configure.in no longer needs to recognize Cygwin specially.
1652    
1653     6. A problem in pcre.in for Windows platforms is fixed.
1654    
1655     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1656        pcretest, it used to include the size of the study block as part of its
1657        output. Unfortunately, the structure contains a field that has a different
1658        size on different hardware architectures. This meant that the tests that
1659        showed this size failed. As the block is currently always of a fixed size,
1660        this information isn't actually particularly useful in pcretest output, so
1661        I have just removed it.
1662    
1663     8. Three pre-processor statements accidentally did not start in column 1.
1664        Sadly, there are *still* compilers around that complain, even though
1665        standard C has not required this for well over a decade. Sigh.
1666    
1667     9. In pcretest, the code for checking callouts passed small integers in the
1668        callout_data field, which is a void * field. However, some picky compilers
1669        complained about the casts involved for this on 64-bit systems. Now
1670        pcretest passes the address of the small integer instead, which should get
1671        rid of the warnings.
1672    
1673    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1674        both compile and run time, and gives an error if an invalid UTF-8 sequence
1675        is found. There is a option for disabling this check in cases where the
1676        string is known to be correct and/or the maximum performance is wanted.
1677    
1678    11. In response to a bug report, I changed one line in Makefile.in from
1679    
1680            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1681        to
1682            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1683    
1684        to look similar to other lines, but I have no way of telling whether this
1685        is the right thing to do, as I do not use Windows. No doubt I'll get told
1686        if it's wrong...
1687    
1688    
1689    Version 4.3 21-May-03
1690    ---------------------
1691    
1692    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1693       Makefile.
1694    
1695    2. Some refactoring to improve the quality of the code:
1696    
1697       (i)   The utf8_table... variables are now declared "const".
1698    
1699       (ii)  The code for \cx, which used the "case flipping" table to upper case
1700             lower case letters, now just substracts 32. This is ASCII-specific,
1701             but the whole concept of \cx is ASCII-specific, so it seems
1702             reasonable.
1703    
1704       (iii) PCRE was using its character types table to recognize decimal and
1705             hexadecimal digits in the pattern. This is silly, because it handles
1706             only 0-9, a-f, and A-F, but the character types table is locale-
1707             specific, which means strange things might happen. A private
1708             table is now used for this - though it costs 256 bytes, a table is
1709             much faster than multiple explicit tests. Of course, the standard
1710             character types table is still used for matching digits in subject
1711             strings against \d.
1712    
1713       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1714             ending in _t are). So I've renamed it as ESC_tee.
1715    
1716    3. The first argument for regexec() in the POSIX wrapper should have been
1717       defined as "const".
1718    
1719    4. Changed pcretest to use malloc() for its buffers so that they can be
1720       Electric Fenced for debugging.
1721    
1722    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1723       to read one or more bytes before the start of the subject string. Often this
1724       had no effect on PCRE's behaviour, but in some circumstances it could
1725       provoke a segmentation fault.
1726    
1727    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1728       to try to read one or more bytes before the start of the subject string.
1729    
1730    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1731       UTF-8 support could misbehave in various ways if the subject string
1732       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1733       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1734       back over UTF-8 characters.)
1735    
1736    
1737    Version 4.2 14-Apr-03
1738    ---------------------
1739    
1740    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1741    
1742    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1743         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1744         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1745         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1746         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1747           and BUILD_EXEEXT
1748         Note: automatic setting of the BUILD variables is not yet working
1749         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1750           compile-time but not at link-time
1751         [LINK]: use for linking executables only
1752         make different versions for Windows and non-Windows
1753         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1754           libraries
1755         [LINK_FOR_BUILD]: new variable
1756         [OBJEXT]: use throughout
1757         [EXEEXT]: use throughout
1758         <winshared>: new target
1759         <wininstall>: new target
1760         <dftables.o>: use native compiler
1761         <dftables>: use native linker
1762         <install>: handle Windows platform correctly
1763         <clean>: ditto
1764         <check>: ditto
1765         copy DLL to top builddir before testing
1766    
1767       As part of these changes, -no-undefined was removed again. This was reported
1768       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1769       in any case.
1770    
1771    3. Some tidies to get rid of compiler warnings:
1772    
1773       . In the match_data structure, match_limit was an unsigned long int, whereas
1774         match_call_count was an int. I've made them both unsigned long ints.
1775    
1776       . In pcretest the fact that a const uschar * doesn't automatically cast to
1777         a void * provoked a warning.
1778    
1779       . Turning on some more compiler warnings threw up some "shadow" variables
1780         and a few more missing casts.
1781    
1782    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1783       option, a class that contained a single character with a value between 128
1784       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1785    
1786    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1787       option, a class that contained several characters, but with at least one
1788       whose value was between 128 and 255 caused PCRE to crash.
1789    
1790    
1791    Version 4.1 12-Mar-03
1792    ---------------------
1793    
1794    1. Compiling with gcc -pedantic found a couple of places where casts were
1795    needed, and a string in dftables.c that was longer than standard compilers are
1796    required to support.
1797    
1798    2. Compiling with Sun's compiler found a few more places where the code could
1799    be tidied up in order to avoid warnings.
1800    
1801    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1802    first of these names is deprecated in the latest Autoconf in favour of the name
1803    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1804    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1805    analogy I have changed it to CFLAGS_FOR_BUILD.
1806    
1807    4. Added -no-undefined to the linking command in the Makefile, because this is
1808    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1809    linking step for the pcreposix library.
1810    
1811    5. PCRE was failing to diagnose the case of two named groups with the same
1812    name.
1813    
1814    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1815    literal character that is needed in the subject for a match, and scans along to
1816    ensure that it is present before embarking on the full matching process. This
1817    saves time in cases of nested unlimited repeats that are never going to match.
1818    Problem: the scan can take a lot of time if the subject is very long (e.g.
1819    megabytes), thus penalizing straightforward matches. It is now done only if the
1820    amount of subject to be scanned is less than 1000 bytes.
1821    
1822    7. A lesser problem with the same optimization is that it was recording the
1823    first character of an anchored pattern as "needed", thus provoking a search
1824    right along the subject, even when the first match of the pattern was going to
1825    fail. The "needed" character is now not set for anchored patterns, unless it
1826    follows something in the pattern that is of non-fixed length. Thus, it still
1827    fulfils its original purpose of finding quick non-matches in cases of nested
1828    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1829    
1830    
1831    Version 4.0 17-Feb-03
1832    ---------------------
1833    
1834    1. If a comment in an extended regex that started immediately after a meta-item
1835    extended to the end of string, PCRE compiled incorrect data. This could lead to
1836    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1837    
1838    2. Moved to autoconf 2.53 and libtool 1.4.2.
1839    
1840    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1841    the special perltest8 script is no longer needed - all the tests can be run
1842    from a single perltest script.
1843    
1844    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1845    by \s. It has now been removed in PCRE. This means it isn't recognized as
1846    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1847    class [:space:] *does* include VT, thereby creating a mess.
1848    
1849    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1850    space and tab.
1851    
1852    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1853    its new features into the main test script, reducing the number of scripts.
1854    
1855    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1856    were backward compatible, and made the (?i) apply to the whole pattern, as if
1857    /i were given. Now it behaves more logically, and applies the option setting
1858    only to what follows. PCRE has been changed to follow suit. However, if it
1859    finds options settings right at the start of the pattern, it extracts them into
1860    the global options, as before. Thus, they show up in the info data.
1861    
1862    8. Added support for the \Q...\E escape sequence. Characters in between are
1863    treated as literals. This is slightly different from Perl in that $ and @ are
1864    also handled as literals inside the quotes. In Perl, they will cause variable
1865    interpolation. Note the following examples:
1866    
1867        Pattern            PCRE matches      Perl matches
1868    
1869        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1870        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1871        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1872    
1873    For compatibility with Perl, \Q...\E sequences are recognized inside character
1874    classes as well as outside them.
1875    
1876    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1877    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1878    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1879    signed/unsigned warnings.
1880    
1881    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1882    option for pcretest, so I've replaced it by a simple function that does just
1883    that job.
1884    
1885    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1886    "pcregrep -".
1887    
1888    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1889    Java package. This provides some syntactic sugar for simple cases of what my
1890    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1891    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1892    item, you can use this simplified notation. Note that only makes sense with
1893    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1894    greediness, whatever the setting of the PCRE_UNGREEDY option.
1895    
1896    13. A change of greediness default within a pattern was not taking effect at
1897    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1898    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1899    was abstracted outside.
1900    
1901    14. PCRE now supports the \G assertion. It is true when the current matching
1902    position is at the start point of the match. This differs from \A when the
1903    starting offset is non-zero. Used with the /g option of pcretest (or similar
1904    code), it works in the same way as it does for Perl's /g option. If all
1905    alternatives of a regex begin with \G, the expression is anchored to the start
1906    match position, and the "anchored" flag is set in the compiled expression.
1907    
1908    15. Some bugs concerning the handling of certain option changes within patterns
1909    have been fixed. These applied to options other than (?ims). For example,
1910    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1911    been the other way round. Some of this was related to change 7 above.
1912    
1913    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1914    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1915    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1916    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1917    
1918    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1919    mode. Unlike ".", it always matches newline, whatever the setting of
1920    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1921    assertions. Perl allows it, but it doesn't (in general) work because it can't
1922    calculate the length of the lookbehind. At least, that's the case for Perl
1923    5.8.0 - I've been told they are going to document that it doesn't work in
1924    future.
1925    
1926    18. Added an error diagnosis for escapes that PCRE does not support: these are
1927    \L, \l, \N, \P, \p, \U, \u, and \X.
1928    
1929    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1930    reading past the end of the pattern in cases such as /[abcd/.
1931    
1932    20. PCRE was getting more memory than necessary for patterns with classes that
1933    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1934    
1935    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1936    compiling PCRE for use with Virtual Pascal.
1937    
1938    22. Small fix to the Makefile to make it work properly if the build is done
1939    outside the source tree.
1940    
1941    23. Added a new extension: a condition to go with recursion. If a conditional
1942    subpattern starts with (?(R) the "true" branch is used if recursion has
1943    happened, whereas the "false" branch is used only at the top level.
1944    
1945    24. When there was a very long string of literal characters (over 255 bytes
1946    without UTF support, over 250 bytes with UTF support), the computation of how
1947    much memory was required could be incorrect, leading to segfaults or other
1948    strange effects.
1949    
1950    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1951    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1952    there was a subsequent back reference to those brackets. This meant that, for
1953    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1954    possible to check for precisely this case. All we can do is abandon the
1955    optimization if .* occurs inside capturing brackets when there are any back
1956    references whatsoever. (See below for a better fix that came later.)
1957    
1958    26. The handling of the optimization for finding the first character of a
1959    non-anchored pattern, and for finding a character that is required later in the
1960    match were failing in some cases. This didn't break the matching; it just
1961    failed to optimize when it could. The way this is done has been re-implemented.
1962    
1963    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1964    
1965    28. Added a new feature that provides some of the functionality that Perl
1966    provides with (?{...}). The facility is termed a "callout". The way it is done
1967    in PCRE is for the caller to provide an optional function, by setting
1968    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1969    global variable. By default it is unset, which disables all calling out. To get
1970    the function called, the regex must include (?C) at appropriate points. This
1971    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1972    This provides a means of identifying different callout points. When PCRE
1973    reaches such a point in the regex, if pcre_callout has been set, the external
1974    function is called. It is provided with data in a structure called
1975    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1976    matching continues; if it returns a non-zero value, the match at the current
1977    point fails. However, backtracking will occur if possible. [This was changed
1978    later and other features added - see item 49 below.]
1979    
1980    29. pcretest is upgraded to test the callout functionality. It provides a
1981    callout function that displays information. By default, it shows the start of
1982    the match and the current position in the text. There are some new data escapes
1983    to vary what happens:
1984    
1985        \C+         in addition, show current contents of captured substrings
1986        \C-         do not supply a callout function
1987        \C!n        return 1 when callout number n is reached
1988        \C!n!m      return 1 when callout number n is reached for the mth time
1989    
1990    30. If pcregrep was called with the -l option and just a single file name, it
1991    output "<stdin>" if a match was found, instead of the file name.
1992    
1993    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1994    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1995    pcre_exec(). This saves a malloc/free per call. The default value of
1996    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1997    when configuring.
1998    
1999    32. The default maximum size of a compiled pattern is 64K. There have been a
2000    few cases of people hitting this limit. The code now uses macros to handle the
2001    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2002    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2003    configuring. Tests 2 and 5 work only with 2-byte links because they output
2004    debugging information about compiled patterns.
2005    
2006    33. Internal code re-arrangements:
2007    
2008    (a) Moved the debugging function for printing out a compiled regex into
2009        its own source file (printint.c) and used #include to pull it into
2010        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2011        separate copies.
2012    
2013    (b) Defined the list of op-code names for debugging as a macro in
2014        internal.h so that it is next to the definition of the opcodes.
2015    
2016    (c) Defined a table of op-code lengths for simpler skipping along compiled
2017        code. This is again a macro in internal.h so that it is next to the
2018        definition of the opcodes.
2019    
2020    34. Added support for recursive calls to individual subpatterns, along the
2021    lines of Robin Houston's patch (but implemented somewhat differently).
2022    
2023    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2024    allow it to read and process whole directories in Win32. This code was
2025    contributed by Lionel Fourquaux; it has not been tested by me.
2026    
2027    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2028    used to name a group. Names consist of alphanumerics and underscores, and must
2029    be unique. Back references use the syntax (?P=name) and recursive calls use
2030    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2031    numbers. The function pcre_fullinfo() can be used after compilation to extract
2032    a name/number map. There are three relevant calls:
2033    
2034      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2035      PCRE_INFO_NAMECOUNT            yields the number of entries
2036      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2037    
2038    The map is a vector of fixed-size entries. The size of each entry depends on
2039    the length of the longest name used. The first two bytes of each entry are the
2040    group number, most significant byte first. There follows the corresponding
2041    name, zero terminated. The names are in alphabetical order.
2042    
2043    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2044    case instead of 255. Making it the same both with and without UTF-8 support
2045    means that the same test output works with both.
2046    
2047    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2048    calling malloc() with a zero argument.
2049    
2050    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2051    optimization. I've improved things by keeping a bitmap of backreferences with
2052    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2053    fact referenced, the optimization can be applied. It is unlikely that a
2054    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2055    the match to follow \n) will appear inside brackets with a number greater than
2056    31, but if it does, any back reference > 31 suppresses the optimization.
2057    
2058    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2059    of disabling numbered capturing parentheses. Any opening parenthesis that is
2060    not followed by ? behaves as if it were followed by ?: but named parentheses
2061    can still be used for capturing (and they will acquire numbers in the usual
2062    way).
2063    
2064    41. Redesigned the return codes from the match() function into yes/no/error so
2065    that errors can be passed back from deep inside the nested calls. A malloc
2066    failure while inside a recursive subpattern call now causes the
2067    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2068    
2069    42. It is now possible to set a limit on the number of times the match()
2070    function is called in a call to pcre_exec(). This facility makes it possible to
2071    limit the amount of recursion and backtracking, though not in a directly
2072    obvious way, because the match() function is used in a number of different
2073    circumstances. The count starts from zero for each position in the subject
2074    string (for non-anchored patterns). The default limit is, for compatibility, a
2075    large number, namely 10 000 000. You can change this in two ways:
2076    
2077    (a) When configuring PCRE before making, you can use --with-match-limit=n
2078        to set a default value for the compiled library.
2079    
2080    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2081        a different value is set. See 45 below.
2082    
2083    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2084    
2085    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2086    of things that can be changed at compile time. The first argument specifies
2087    what is wanted and the second points to where the information is to be placed.
2088    The current list of available information is:
2089    
2090      PCRE_CONFIG_UTF8
2091    
2092    The output is an integer that is set to one if UTF-8 support is available;
2093    otherwise it is set to zero.
2094    
2095      PCRE_CONFIG_NEWLINE
2096    
2097    The output is an integer that it set to the value of the code that is used for
2098    newline. It is either LF (10) or CR (13).
2099    
2100      PCRE_CONFIG_LINK_SIZE
2101    
2102    The output is an integer that contains the number of bytes used for internal
2103    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2104    
2105      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2106    
2107    The output is an integer that contains the threshold above which the POSIX
2108    interface uses malloc() for output vectors. See item 31 above.
2109    
2110      PCRE_CONFIG_MATCH_LIMIT
2111    
2112    The output is an unsigned integer that contains the default limit of the number
2113    of match() calls in a pcre_exec() execution. See 42 above.
2114    
2115    44. pcretest has been upgraded by the addition of the -C option. This causes it
2116    to extract all the available output from the new pcre_config() function, and to
2117    output it. The program then exits immediately.
2118    
2119    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2120    order to support additional features. One way would have been to define
2121    pcre_exec2() (for example) with extra arguments, but this would not have been
2122    extensible, and would also have required all calls to the original function to
2123    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2124    is used for passing in "extra" data from pcre_study().
2125    
2126    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2127    contains the following fields:
2128    
2129      flags         a bitmap indicating which of the following fields are set
2130      study_data    opaque data from pcre_study()
2131      match_limit   a way of specifying a limit on match() calls for a specific
2132                      call to pcre_exec()
2133      callout_data  data for callouts (see 49 below)
2134    
2135    The flag bits are also defined in pcre.h, and are
2136    
2137      PCRE_EXTRA_STUDY_DATA
2138      PCRE_EXTRA_MATCH_LIMIT
2139      PCRE_EXTRA_CALLOUT_DATA
2140    
2141    The pcre_study() function now returns one of these new pcre_extra blocks, with
2142    the actual study data pointed to by the study_data field, and the
2143    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2144    before. That is, this change is entirely upwards-compatible and requires no
2145    change to existing code.
2146    
2147    If you want to pass in additional data to pcre_exec(), you can either place it
2148    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2149    block.
2150    
2151    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2152    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2153    times with different match limits, until it finds the minimum value needed for
2154    pcre_exec() to complete. The value is then output. This can be instructive; for
2155    most simple matches the number is quite small, but for pathological cases it
2156    gets very large very quickly.
2157    
2158    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2159    returns the size of the data block pointed to by the study_data field in a
2160    pcre_extra block, that is, the value that was passed as the argument to
2161    pcre_malloc() when PCRE was getting memory in which to place the information
2162    created by pcre_study(). The fourth argument should point to a size_t variable.
2163    pcretest has been extended so that this information is shown after a successful
2164    pcre_study() call when information about the compiled regex is being displayed.
2165    
2166    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2167    because what follows is always an absolute path. (Later: it turns out that this
2168    is more than cosmetic for MinGW, because it doesn't like empty path
2169    components.)
2170    
2171    49. Some changes have been made to the callout feature (see 28 above):
2172    
2173    (i)  A callout function now has three choices for what it returns:
2174    
2175           0  =>  success, carry on matching
2176         > 0  =>  failure at this point, but backtrack if possible
2177         < 0  =>  serious error, return this value from pcre_exec()
2178    
2179         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2180         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2181         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2182         use by callout functions. It will never be used by PCRE itself.
2183    
2184    (ii) The pcre_extra structure (see 45 above) has a void * field called
2185         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2186         pcre_callout_block structure has a field of the same name. The contents of
2187         the field passed in the pcre_extra structure are passed to the callout
2188         function in the corresponding field in the callout block. This makes it
2189         easier to use the same callout-containing regex from multiple threads. For
2190         testing, the pcretest program has a new data escape
2191    
2192           \C*n        pass the number n (may be negative) as callout_data
2193    
2194         If the callout function in pcretest receives a non-zero value as
2195         callout_data, it returns that value.
2196    
2197    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2198    there were some redundant $(CFLAGS) in commands that are now specified as
2199    $(LINK), which already includes $(CFLAGS).
2200    
2201    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2202    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2203    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2204    one-byte characters throughout. Note that case-insensitive matching applies
2205    only to characters whose values are less than 256. PCRE doesn't support the
2206    notion of cases for higher-valued characters.
2207    
2208    (i)   A character class whose characters are all within 0-255 is handled as
2209          a bit map, and the map is inverted for negative classes. Previously, a
2210          character > 255 always failed to match such a class; however it should
2211          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2212    
2213    (ii)  A negated character class with a single character < 255 is coded as
2214          "not this character" (OP_NOT). This wasn't working properly when the test
2215          character was multibyte, either singly or repeated.
2216    
2217    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2218          mode, for example: \x{100}{2,3}.
2219    
2220    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2221          singly or repeated) now correctly test multibyte characters. However,
2222          PCRE doesn't recognize any characters with values greater than 255 as
2223          digits, spaces, or word characters. Such characters always match \D, \S,
2224          and \W, and never match \d, \s, or \w.
2225    
2226    (v)   Classes may now contain characters and character ranges with values
2227          greater than 255. For example: [ab\x{100}-\x{400}].
2228    
2229    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2230          PCRE in UTF-8 mode.
2231    
2232    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2233    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2234    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2235    value.)
2236    
2237    53. The single man page has become too large. I have therefore split it up into
2238    a number of separate man pages. These also give rise to individual HTML pages;
2239    these are now put in a separate directory, and there is an index.html page that
2240    lists them all. Some hyperlinking between the pages has been installed.
2241    
2242    54. Added convenience functions for handling named capturing parentheses.
2243    
2244    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2245    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2246    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2247    are faulted.
2248    
2249    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2250    calling configure. These values are used when compiling the dftables.c program
2251    which is run to generate the source of the default character tables. They
2252    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2253    you will need to set these values.
2254    
2255    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2256    
2257    
2258    Version 3.9 02-Jan-02
2259    ---------------------
2260    
2261    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2262    
2263    2. If --disable-static was given, the building process failed when trying to
2264    build pcretest and pcregrep. (For some reason it was using libtool to compile
2265    them, which is not right, as they aren't part of the library.)
2266    
2267    
2268    Version 3.8 18-Dec-01
2269    ---------------------
2270    
2271    1. The experimental UTF-8 code was completely screwed up. It was packing the
2272    bytes in the wrong order. How dumb can you get?
2273    
2274    
2275    Version 3.7 29-Oct-01
2276    ---------------------
2277    
2278    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2279    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2280    this didn't happen under Solaris 8, where I normally test things.
2281    
2282    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2283    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2284    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2285    this fix an hour or so after the initial 3.7 release.)
2286    
2287    
2288    Version 3.6 23-Oct-01
2289    ---------------------
2290    
2291    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2292    offsets passed as NULL with zero offset count.
2293    
2294    2. The config.guess and config.sub files had not been updated when I moved to
2295    the latest autoconf.
2296    
2297    
2298    Version 3.5 15-Aug-01
2299    ---------------------
2300    
2301    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2302    had been forgotten.
2303    
2304    2. By using declared but undefined structures, we can avoid using "void"
2305    definitions in pcre.h while keeping the internal definitions of the structures
2306    private.
2307    
2308    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2309    user point of view, this means that both static and shared libraries are built
2310    by default, but this can be individually controlled. More of the work of
2311    handling this static/shared cases is now inside libtool instead of PCRE's make
2312    file.
2313    
2314    4. The pcretest utility is now installed along with pcregrep because it is
2315    useful for users (to test regexs) and by doing this, it automatically gets
2316    relinked by libtool. The documentation has been turned into a man page, so
2317    there are now .1, .txt, and .html versions in /doc.
2318    
2319    5. Upgrades to pcregrep:
2320       (i)   Added long-form option names like gnu grep.
2321       (ii)  Added --help to list all options with an explanatory phrase.
2322       (iii) Added -r, --recursive to recurse into sub-directories.
2323       (iv)  Added -f, --file to read patterns from a file.
2324    
2325    6. pcre_exec() was referring to its "code" argument before testing that
2326    argument for NULL (and giving an error if it was NULL).
2327    
2328    7. Upgraded Makefile.in to allow for compiling in a different directory from
2329    the source directory.
2330    
2331    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2332    options bits, the pointer it was passed was to an int instead of to an unsigned
2333    long int. This mattered only on 64-bit systems.
2334    
2335    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2336    generated) instead of pcre.in, which it its source. Also made the same change
2337    in several of the .c files.
2338    
2339    10. A new release of gcc defines printf() as a macro, which broke pcretest
2340    because it had an ifdef in the middle of a string argument for printf(). Fixed
2341    by using separate calls to printf().
2342    
2343    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2344    script, to force use of CR or LF instead of \n in the source. On non-Unix
2345    systems, the value can be set in config.h.
2346    
2347    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2348    absolute limit. Changed the text of the error message to make this clear, and
2349    likewise updated the man page.
2350    
2351    13. The limit of 99 on the number of capturing subpatterns has been removed.
2352    The new limit is 65535, which I hope will not be a "real" limit.
2353    
2354    
2355    Version 3.4 22-Aug-00
2356    ---------------------
2357    
2358    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2359    
2360    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2361    
2362    
2363    Version 3.3 01-Aug-00
2364    ---------------------
2365    
2366    1. If an octal character was given, but the value was greater than \377, it
2367    was not getting masked to the least significant bits, as documented. This could
2368    lead to crashes in some systems.
2369    
2370    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2371    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2372    
2373    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2374    These just pass their arguments on to (pcre_free)(), but they are provided
2375    because some uses of PCRE bind it to non-C systems that can call its functions,
2376    but cannot call free() or pcre_free() directly.
2377    
2378    4. Add "make test" as a synonym for "make check". Corrected some comments in
2379    the Makefile.
2380    
2381    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2382    Makefile.
2383    
2384    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2385    command called pgrep for grepping around the active processes.
2386    
2387    7. Added the beginnings of support for UTF-8 character strings.
2388    
2389    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2390    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2391    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2392    out for the ar command.)
2393    
2394    
2395    Version 3.2 12-May-00
2396    ---------------------
2397    
2398    This is purely a bug fixing release.
2399    
2400    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2401    of ZA. This was just one example of several cases that could provoke this bug,
2402    which was introduced by change 9 of version 2.00. The code for breaking
2403    infinite loops after an iteration that matches an empty string was't working
2404    correctly.
2405    
2406    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2407    when matched against abbab (for example). After matching an empty string, it
2408    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2409    caused it to match further down the string than it should.
2410    
2411    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2412    was there because it doesn't seem to be needed, and it causes trouble on some
2413    systems, as it is not a Standard C header. It has been removed.
2414    
2415    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2416    were reported on the Macintosh. The changes were from
2417    
2418      while ((c = *(++ptr)) != 0 && c != '\n');
2419    to
2420      while ((c = *(++ptr)) != 0 && c != '\n') ;
2421    
2422    Totally extraordinary, but if that's what it takes...
2423    
2424    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2425    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2426    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2427    assumes the way PCRE uses memmove() (always moving upwards).
2428    
2429    6. PCRE is being used in one environment where strchr() is not available. There
2430    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2431    faster code anyway.
2432    
2433    
2434    Version 3.1 09-Feb-00
2435    ---------------------
2436    
2437    The only change in this release is the fixing of some bugs in Makefile.in for
2438    the "install" target:
2439    
2440    (1) It was failing to install pcreposix.h.
2441    
2442    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2443    
2444  Version 2.09 14-Sep-99  
2445  ----------------------  Version 3.0 01-Feb-00
2446    ---------------------
2447    
2448  1. Add support for the /+ modifier to perltest (to output $` like it does in  1. Add support for the /+ modifier to perltest (to output $` like it does in
2449  pcretest).  pcretest).
# Line 23  captured string vector to pcre_exec(), b Line 2463  captured string vector to pcre_exec(), b
2463  required a bigger vector, with some working space on the end. This means that  required a bigger vector, with some working space on the end. This means that
2464  the POSIX wrapper now has to get and free some memory, and copy the results.  the POSIX wrapper now has to get and free some memory, and copy the results.
2465    
2466    6. Added some simple autoconf support, placing the test data and the
2467    documentation in separate directories, re-organizing some of the
2468    information files, and making it build pcre-config (a GNU standard). Also added
2469    libtool support for building PCRE as a shared library, which is now the
2470    default.
2471    
2472    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2473    09 are not valid octal constants. Single digits will be used for minor values
2474    less than 10.
2475    
2476    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2477    existing programs that set these in the POSIX interface can use PCRE without
2478    modification.
2479    
2480    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2481    return all that pcre_info() returns, plus additional data. The pcre_info()
2482    function is retained for compatibility, but is considered to be obsolete.
2483    
2484    10. Added experimental recursion feature (?R) to handle one common case that
2485    Perl 5.6 will be able to do with (?p{...}).
2486    
2487    11. Added support for POSIX character classes like [:alpha:], which Perl is
2488    adopting.
2489    
2490    
2491  Version 2.08 31-Aug-99  Version 2.08 31-Aug-99
2492  ----------------------  ----------------------

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