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revision 37 by nigel, Sat Feb 24 21:39:09 2007 UTC revision 297 by ph10, Fri Jan 4 19:44:00 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.5 04-Jan-08
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
44    
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
47    
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
54    
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
68    
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
73    
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
78    
79    14. Added --file-offsets and --line-offsets to pcregrep.
80    
81    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82        infinitely looping recursion. The bug was that positive lookaheads were not
83        being skipped when checking for a possible empty match (negative lookaheads
84        and both kinds of lookbehind were skipped).
85    
86    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87        inclusion of <windows.h> to before rather than after the definition of
88        INVALID_FILE_ATTRIBUTES (patch from David Byron).
89    
90    17. Specifying a possessive quantifier with a specific limit for a Unicode
91        character property caused pcre_compile() to compile bad code, which led at
92        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94        caused the error; without that there was no problem.
95    
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
97    
98    19. Added --enable-pcretest-libreadline.
99    
100    20. In pcrecpp.cc, the variable 'count' was incremented twice in
101        RE::GlobalReplace(). As a result, the number of replacements returned was
102        double what it should be. I removed one of the increments, but Craig sent a
103        later patch that removed the other one (the right fix) and added unit tests
104        that check the return values (which was not done before).
105    
106    21. Several CMake things:
107    
108        (1) Arranged that, when cmake is used on Unix, the libraries end up with
109            the names libpcre and libpcreposix, not just pcre and pcreposix.
110    
111        (2) The above change means that pcretest and pcregrep are now correctly
112            linked with the newly-built libraries, not previously installed ones.
113    
114        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
115    
116    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
117        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
118        UTF-8 newline character). The key issue is that the pattern starts .*;
119        this means that the match must be either at the beginning, or after a
120        newline. The bug was in the code for advancing after a failed match and
121        checking that the new position followed a newline. It was not taking
122        account of UTF-8 characters correctly.
123    
124    23. PCRE was behaving differently from Perl in the way it recognized POSIX
125        character classes. PCRE was not treating the sequence [:...:] as a
126        character class unless the ... were all letters. Perl, however, seems to
127        allow any characters between [: and :], though of course it rejects as
128        unknown any "names" that contain non-letters, because all the known class
129        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
130        for example, whereas PCRE did not - it did not recognize a POSIX character
131        class. This seemed a bit dangerous, so the code has been changed to be
132        closer to Perl. The behaviour is not identical to Perl, because PCRE will
133        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
134        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
135        Perl does, and where it didn't before.
136    
137    24. Rewrite so as to remove the single use of %n from pcregrep because in some
138        Windows environments %n is disabled by default.
139    
140    
141    Version 7.4 21-Sep-07
142    ---------------------
143    
144    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
145        means that a class such as [\s] counted as "explicit reference to CR or
146        LF". That isn't really right - the whole point of the change was to try to
147        help when there was an actual mention of one of the two characters. So now
148        the change happens only if \r or \n (or a literal CR or LF) character is
149        encountered.
150    
151    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
152        of both had grown to the point where there were only 3 bits left.
153        Fortunately, there was spare space in the data structure, and so I have
154        moved the internal flags into a new 16-bit field to free up more option
155        bits.
156    
157    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
158        but did not set the internal JCHANGED flag - either of these is enough to
159        control the way the "get" function works - but the PCRE_INFO_JCHANGED
160        facility is supposed to tell if (?J) was ever used, so now (?J) at the
161        start sets both bits.
162    
163    4.  Added options (at build time, compile time, exec time) to change \R from
164        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
165    
166    5.  doc/pcresyntax.html was missing from the distribution.
167    
168    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
169        compatibility, even though it is no longer used.
170    
171    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
172        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
173        windows.h file is present (where different names are used). [This was
174        reversed later after testing - see 16 below.]
175    
176    8.  Changed all #include <config.h> to #include "config.h". There were also
177        some further <pcre.h> cases that I changed to "pcre.h".
178    
179    9.  When pcregrep was used with the --colour option, it missed the line ending
180        sequence off the lines that it output.
181    
182    10. It was pointed out to me that arrays of string pointers cause lots of
183        relocations when a shared library is dynamically loaded. A technique of
184        using a single long string with a table of offsets can drastically reduce
185        these. I have refactored PCRE in four places to do this. The result is
186        dramatic:
187    
188          Originally:                          290
189          After changing UCP table:            187
190          After changing error message table:   43
191          After changing table of "verbs"       36
192          After changing table of Posix names   22
193    
194        Thanks to the folks working on Gregex for glib for this insight.
195    
196    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
197        unicode-properties was also set.
198    
199    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
200    
201    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
202        checked only for CRLF.
203    
204    14. Added casts to pcretest.c to avoid compiler warnings.
205    
206    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
207    
208    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
209        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
210        entirely. This removes changes made in 7 above.
211    
212    17. The CMake files have been updated, and there is now more information about
213        building with CMake in the NON-UNIX-USE document.
214    
215    
216    Version 7.3 28-Aug-07
217    ---------------------
218    
219     1. In the rejigging of the build system that eventually resulted in 7.1, the
220        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
221        brackets there is not right, since it causes compilers to look for an
222        installed pcre.h, not the version that is in the source that is being
223        compiled (which of course may be different). I have changed it back to:
224    
225          #include "pcre.h"
226    
227        I have a vague recollection that the change was concerned with compiling in
228        different directories, but in the new build system, that is taken care of
229        by the VPATH setting the Makefile.
230    
231     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
232        when the subject happened to end in the byte 0x85 (e.g. if the last
233        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
234        characters but of course it shouldn't be taken as a newline when it is part
235        of another character. The bug was that, for an unlimited repeat of . in
236        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
237        characters when looking for a newline.
238    
239     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
240    
241     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
242        in debug output.
243    
244     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
245        long printing in the pcrecpp unittest when running under MinGW.
246    
247     6. ESC_K was left out of the EBCDIC table.
248    
249     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
250        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
251        limit also applies to "virtual nesting" when a pattern is recursive, and in
252        this case 1000 isn't so big. I have been able to remove this limit at the
253        expense of backing off one optimization in certain circumstances. Normally,
254        when pcre_exec() would call its internal match() function recursively and
255        immediately return the result unconditionally, it uses a "tail recursion"
256        feature to save stack. However, when a subpattern that can match an empty
257        string has an unlimited repetition quantifier, it no longer makes this
258        optimization. That gives it a stack frame in which to save the data for
259        checking that an empty string has been matched. Previously this was taken
260        from the 1000-entry workspace that had been reserved. So now there is no
261        explicit limit, but more stack is used.
262    
263     8. Applied Daniel's patches to solve problems with the import/export magic
264        syntax that is required for Windows, and which was going wrong for the
265        pcreposix and pcrecpp parts of the library. These were overlooked when this
266        problem was solved for the main library.
267    
268     9. There were some crude static tests to avoid integer overflow when computing
269        the size of patterns that contain repeated groups with explicit upper
270        limits. As the maximum quantifier is 65535, the maximum group length was
271        set at 30,000 so that the product of these two numbers did not overflow a
272        32-bit integer. However, it turns out that people want to use groups that
273        are longer than 30,000 bytes (though not repeat them that many times).
274        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
275        made it possible to implement the integer overflow checks in a much more
276        dynamic way, which I have now done. The artificial limitation on group
277        length has been removed - we now have only the limit on the total length of
278        the compiled pattern, which depends on the LINK_SIZE setting.
279    
280    10. Fixed a bug in the documentation for get/copy named substring when
281        duplicate names are permitted. If none of the named substrings are set, the
282        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
283        empty string.
284    
285    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
286        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
287        because the ] is interpreted as the first data character and the
288        terminating ] is not found. PCRE has been made compatible with Perl in this
289        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
290        cause memory overwriting.
291    
292    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
293        string has been matched (to stop an infinite loop). It was not recognizing
294        a conditional subpattern that could match an empty string if that
295        subpattern was within another subpattern. For example, it looped when
296        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
297        condition was not nested. This bug has been fixed.
298    
299    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
300        past the start of the subject in the presence of bytes with the top bit
301        set, for example "\x8aBCD".
302    
303    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
304        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
305    
306    14. Optimized (?!) to (*FAIL).
307    
308    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
309        This restricts code points to be within the range 0 to 0x10FFFF, excluding
310        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
311        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
312        does: it's just the validity check that is more restrictive.
313    
314    16. Inserted checks for integer overflows during escape sequence (backslash)
315        processing, and also fixed erroneous offset values for syntax errors during
316        backslash processing.
317    
318    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
319        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
320    
321    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
322        caused an overrun.
323    
324    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
325        something other than just ASCII characters) inside a group that had an
326        unlimited repeat caused a loop at compile time (while checking to see
327        whether the group could match an empty string).
328    
329    20. Debugging a pattern containing \p or \P could cause a crash. For example,
330        [\P{Any}] did so. (Error in the code for printing property names.)
331    
332    21. An orphan \E inside a character class could cause a crash.
333    
334    22. A repeated capturing bracket such as (A)? could cause a wild memory
335        reference during compilation.
336    
337    23. There are several functions in pcre_compile() that scan along a compiled
338        expression for various reasons (e.g. to see if it's fixed length for look
339        behind). There were bugs in these functions when a repeated \p or \P was
340        present in the pattern. These operators have additional parameters compared
341        with \d, etc, and these were not being taken into account when moving along
342        the compiled data. Specifically:
343    
344        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
345            length.
346    
347        (b) An item such as \pL+ within a repeated group could cause crashes or
348            loops.
349    
350        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
351            "reference to non-existent subpattern" error.
352    
353        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
354    
355    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
356        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
357    
358    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
359    
360    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
361        character were causing crashes (broken optimization).
362    
363    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
364        \p or \P) caused a compile-time loop.
365    
366    28. More problems have arisen in unanchored patterns when CRLF is a valid line
367        break. For example, the unstudied pattern [\r\n]A does not match the string
368        "\r\nA" because change 7.0/46 below moves the current point on by two
369        characters after failing to match at the start. However, the pattern \nA
370        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
371        the same is true. There doesn't seem any very clean way out of this, but
372        what I have chosen to do makes the common cases work: PCRE now takes note
373        of whether there can be an explicit match for \r or \n anywhere in the
374        pattern, and if so, 7.0/46 no longer applies. As part of this change,
375        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
376        pattern has explicit CR or LF references.
377    
378    29. Added (*CR) etc for changing newline setting at start of pattern.
379    
380    
381    Version 7.2 19-Jun-07
382    ---------------------
383    
384     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
385        which is apparently normally available under Windows.
386    
387     2. Re-jig the pcregrep tests with different newline settings in an attempt
388        to make them independent of the local environment's newline setting.
389    
390     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
391    
392     4. Some of the "internals" tests were previously cut out when the link size
393        was not 2, because the output contained actual offsets. The recent new
394        "Z" feature of pcretest means that these can be cut out, making the tests
395        usable with all link sizes.
396    
397     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
398        stack recursion. This gives a massive performance boost under BSD, but just
399        a small improvement under Linux. However, it saves one field in the frame
400        in all cases.
401    
402     6. Added more features from the forthcoming Perl 5.10:
403    
404        (a) (?-n) (where n is a string of digits) is a relative subroutine or
405            recursion call. It refers to the nth most recently opened parentheses.
406    
407        (b) (?+n) is also a relative subroutine call; it refers to the nth next
408            to be opened parentheses.
409    
410        (c) Conditions that refer to capturing parentheses can be specified
411            relatively, for example, (?(-2)... or (?(+3)...
412    
413        (d) \K resets the start of the current match so that everything before
414            is not part of it.
415    
416        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
417    
418        (f) \g{name} is another synonym - part of Perl 5.10's unification of
419            reference syntax.
420    
421        (g) (?| introduces a group in which the numbering of parentheses in each
422            alternative starts with the same number.
423    
424        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
425    
426     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
427        PCRE_INFO_JCHANGED.
428    
429     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
430        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
431        for detecting groups that can match an empty string.
432    
433     9. A pattern with a very large number of alternatives (more than several
434        hundred) was running out of internal workspace during the pre-compile
435        phase, where pcre_compile() figures out how much memory will be needed. A
436        bit of new cunning has reduced the workspace needed for groups with
437        alternatives. The 1000-alternative test pattern now uses 12 bytes of
438        workspace instead of running out of the 4096 that are available.
439    
440    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
441    
442    11. Applied patch from Google to remove an optimization that didn't quite work.
443        The report of the bug said:
444    
445          pcrecpp::RE("a*").FullMatch("aaa") matches, while
446          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
447          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
448    
449    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
450        it matched the wrong number of bytes.
451    
452    
453    Version 7.1 24-Apr-07
454    ---------------------
455    
456     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
457        that is more "standard", making use of automake and other Autotools. There
458        is some re-arrangement of the files and adjustment of comments consequent
459        on this.
460    
461     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
462        for recursive directory scanning broke on some systems because the files
463        are not scanned in any specific order and on different systems the order
464        was different. A call to "sort" has been inserted into RunGrepTest for the
465        approprate test as a short-term fix. In the longer term there may be an
466        alternative.
467    
468     3. I had an email from Eric Raymond about problems translating some of PCRE's
469        man pages to HTML (despite the fact that I distribute HTML pages, some
470        people do their own conversions for various reasons). The problems
471        concerned the use of low-level troff macros .br and .in. I have therefore
472        removed all such uses from the man pages (some were redundant, some could
473        be replaced by .nf/.fi pairs). The 132html script that I use to generate
474        HTML has been updated to handle .nf/.fi and to complain if it encounters
475        .br or .in.
476    
477     4. Updated comments in configure.ac that get placed in config.h.in and also
478        arranged for config.h to be included in the distribution, with the name
479        config.h.generic, for the benefit of those who have to compile without
480        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
481    
482     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
483        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
484        makevp.bat for the current PCRE, using the additional files
485        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
486    
487     6. A Windows user reported a minor discrepancy with test 2, which turned out
488        to be caused by a trailing space on an input line that had got lost in his
489        copy. The trailing space was an accident, so I've just removed it.
490    
491     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
492        that is needed.
493    
494     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
495        as "const" (a) because they are and (b) because it helps the PHP
496        maintainers who have recently made a script to detect big data structures
497        in the php code that should be moved to the .rodata section. I remembered
498        to update Builducptable as well, so it won't revert if ucptable.h is ever
499        re-created.
500    
501     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
502        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
503        order to be able to cut out the UTF-8 tables in the latter when UTF-8
504        support is not required. This saves 1.5-2K of code, which is important in
505        some applications.
506    
507        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
508        so as not to refer to the tables, even though these functions will never be
509        called when UTF-8 support is disabled. Otherwise there are problems with a
510        shared library.
511    
512    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
513    
514        (a) It was defining its arguments as char * instead of void *.
515    
516        (b) It was assuming that all moves were upwards in memory; this was true
517            a long time ago when I wrote it, but is no longer the case.
518    
519        The emulated memove() is provided for those environments that have neither
520        memmove() nor bcopy(). I didn't think anyone used it these days, but that
521        is clearly not the case, as these two bugs were recently reported.
522    
523    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
524        and Detrail to create the HTML documentation, the .txt form of the man
525        pages, and it removes trailing spaces from listed files. It also creates
526        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
527        case, it wraps all the #defines with #ifndefs. This script should be run
528        before "make dist".
529    
530    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
531        with Unicode property support.
532    
533        (a) For a maximizing quantifier, if the two different cases of the
534            character were of different lengths in their UTF-8 codings (there are
535            some cases like this - I found 11), and the matching function had to
536            back up over a mixture of the two cases, it incorrectly assumed they
537            were both the same length.
538    
539        (b) When PCRE was configured to use the heap rather than the stack for
540            recursion during matching, it was not correctly preserving the data for
541            the other case of a UTF-8 character when checking ahead for a match
542            while processing a minimizing repeat. If the check also involved
543            matching a wide character, but failed, corruption could cause an
544            erroneous result when trying to check for a repeat of the original
545            character.
546    
547    13. Some tidying changes to the testing mechanism:
548    
549        (a) The RunTest script now detects the internal link size and whether there
550            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
551            values substituted by "configure". (The RunGrepTest script already did
552            this for UTF-8.) The configure.ac script no longer substitutes the
553            relevant variables.
554    
555        (b) The debugging options /B and /D in pcretest show the compiled bytecode
556            with length and offset values. This means that the output is different
557            for different internal link sizes. Test 2 is skipped for link sizes
558            other than 2 because of this, bypassing the problem. Unfortunately,
559            there was also a test in test 3 (the locale tests) that used /B and
560            failed for link sizes other than 2. Rather than cut the whole test out,
561            I have added a new /Z option to pcretest that replaces the length and
562            offset values with spaces. This is now used to make test 3 independent
563            of link size. (Test 2 will be tidied up later.)
564    
565    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
566        segmentation fault instead of returning the appropriate error message.
567    
568    15. In multiline mode when the newline sequence was set to "any", the pattern
569        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
570        This doesn't seem right; it now treats the CRLF combination as the line
571        ending, and so does not match in that case. It's only a pattern such as ^$
572        that would hit this one: something like ^ABC$ would have failed after \r
573        and then tried again after \r\n.
574    
575    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
576        in an attempt to make files that differ only in their line terminators
577        compare equal. This works on Linux.
578    
579    17. Under certain error circumstances pcregrep might try to free random memory
580        as it exited. This is now fixed, thanks to valgrind.
581    
582    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
583        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
584        was because its rules for how to advance for /g after matching an empty
585        string at the end of a line did not allow for this case. They now check for
586        it specially.
587    
588    20. pcretest is supposed to handle patterns and data of any length, by
589        extending its buffers when necessary. It was getting this wrong when the
590        buffer for a data line had to be extended.
591    
592    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
593        CRLF as a newline sequence.
594    
595    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
596        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
597        I have nevertheless tidied it up.
598    
599    23. Added some casts to kill warnings from HP-UX ia64 compiler.
600    
601    24. Added a man page for pcre-config.
602    
603    
604    Version 7.0 19-Dec-06
605    ---------------------
606    
607     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
608        moving to gcc 4.1.1.
609    
610     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
611        sys/time.h, which is documented as needed for this function. It doesn't
612        seem to matter on Linux, but it showed up on some releases of OS X.
613    
614     3. It seems that there are systems where bytes whose values are greater than
615        127 match isprint() in the "C" locale. The "C" locale should be the
616        default when a C program starts up. In most systems, only ASCII printing
617        characters match isprint(). This difference caused the output from pcretest
618        to vary, making some of the tests fail. I have changed pcretest so that:
619    
620        (a) When it is outputting text in the compiled version of a pattern, bytes
621            other than 32-126 are always shown as hex escapes.
622    
623        (b) When it is outputting text that is a matched part of a subject string,
624            it does the same, unless a different locale has been set for the match
625            (using the /L modifier). In this case, it uses isprint() to decide.
626    
627     4. Fixed a major bug that caused incorrect computation of the amount of memory
628        required for a compiled pattern when options that changed within the
629        pattern affected the logic of the preliminary scan that determines the
630        length. The relevant options are -x, and -i in UTF-8 mode. The result was
631        that the computed length was too small. The symptoms of this bug were
632        either the PCRE error "internal error: code overflow" from pcre_compile(),
633        or a glibc crash with a message such as "pcretest: free(): invalid next
634        size (fast)". Examples of patterns that provoked this bug (shown in
635        pcretest format) are:
636    
637          /(?-x: )/x
638          /(?x)(?-x: \s*#\s*)/
639          /((?i)[\x{c0}])/8
640          /(?i:[\x{c0}])/8
641    
642        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
643        is now done differently.
644    
645     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
646        wrapper classes; (b) implement a new function in the C++ scanner that is
647        more efficient than the old way of doing things because it avoids levels of
648        recursion in the regex matching; (c) add a paragraph to the documentation
649        for the FullMatch() function.
650    
651     6. The escape sequence \n was being treated as whatever was defined as
652        "newline". Not only was this contrary to the documentation, which states
653        that \n is character 10 (hex 0A), but it also went horribly wrong when
654        "newline" was defined as CRLF. This has been fixed.
655    
656     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
657        was being set to -1 for the "end of line" case (supposedly a value that no
658        character can have). Though this value is never used (the check for end of
659        line is "zero bytes in current character"), it caused compiler complaints.
660        I've changed it to 0xffffffff.
661    
662     8. In pcre_version.c, the version string was being built by a sequence of
663        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
664        string (as it is for production releases) called a macro with an empty
665        argument. The C standard says the result of this is undefined. The gcc
666        compiler treats it as an empty string (which was what was wanted) but it is
667        reported that Visual C gives an error. The source has been hacked around to
668        avoid this problem.
669    
670     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
671        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
672        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
673        of them did).
674    
675    10. Originally, pcretest opened its input and output without "b"; then I was
676        told that "b" was needed in some environments, so it was added for release
677        5.0 to both the input and output. (It makes no difference on Unix-like
678        systems.) Later I was told that it is wrong for the input on Windows. I've
679        now abstracted the modes into two macros, to make it easier to fiddle with
680        them, and removed "b" from the input mode under Windows.
681    
682    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
683    
684    12. Added -help and --help to pcretest as an official way of being reminded
685        of the options.
686    
687    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
688        and pcrecpp.cc because they annoy compilers at high warning levels.
689    
690    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
691    
692    15. Fixed an occurrence of == in configure.ac that should have been = (shell
693        scripts are not C programs :-) and which was not noticed because it works
694        on Linux.
695    
696    16. pcretest is supposed to handle any length of pattern and data line (as one
697        line or as a continued sequence of lines) by extending its input buffer if
698        necessary. This feature was broken for very long pattern lines, leading to
699        a string of junk being passed to pcre_compile() if the pattern was longer
700        than about 50K.
701    
702    17. I have done a major re-factoring of the way pcre_compile() computes the
703        amount of memory needed for a compiled pattern. Previously, there was code
704        that made a preliminary scan of the pattern in order to do this. That was
705        OK when PCRE was new, but as the facilities have expanded, it has become
706        harder and harder to keep it in step with the real compile phase, and there
707        have been a number of bugs (see for example, 4 above). I have now found a
708        cunning way of running the real compile function in a "fake" mode that
709        enables it to compute how much memory it would need, while actually only
710        ever using a few hundred bytes of working memory and without too many
711        tests of the mode. This should make future maintenance and development
712        easier. A side effect of this work is that the limit of 200 on the nesting
713        depth of parentheses has been removed (though this was never a serious
714        limitation, I suspect). However, there is a downside: pcre_compile() now
715        runs more slowly than before (30% or more, depending on the pattern). I
716        hope this isn't a big issue. There is no effect on runtime performance.
717    
718    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
719        newline (only possible for the last line of a file) and it was a
720        pattern that set a locale (followed by /Lsomething), pcretest crashed.
721    
722    19. Added additional timing features to pcretest. (1) The -tm option now times
723        matching only, not compiling. (2) Both -t and -tm can be followed, as a
724        separate command line item, by a number that specifies the number of
725        repeats to use when timing. The default is 50000; this gives better
726        precision, but takes uncomfortably long for very large patterns.
727    
728    20. Extended pcre_study() to be more clever in cases where a branch of a
729        subpattern has no definite first character. For example, (a*|b*)[cd] would
730        previously give no result from pcre_study(). Now it recognizes that the
731        first character must be a, b, c, or d.
732    
733    21. There was an incorrect error "recursive call could loop indefinitely" if
734        a subpattern (or the entire pattern) that was being tested for matching an
735        empty string contained only one non-empty item after a nested subpattern.
736        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
737        incorrectly, because the \d was being skipped in the check.
738    
739    22. The pcretest program now has a new pattern option /B and a command line
740        option -b, which is equivalent to adding /B to every pattern. This causes
741        it to show the compiled bytecode, without the additional information that
742        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
743        is the same as /B/I).
744    
745    23. A new optimization is now able automatically to treat some sequences such
746        as a*b as a*+b. More specifically, if something simple (such as a character
747        or a simple class like \d) has an unlimited quantifier, and is followed by
748        something that cannot possibly match the quantified thing, the quantifier
749        is automatically "possessified".
750    
751    24. A recursive reference to a subpattern whose number was greater than 39
752        went wrong under certain circumstances in UTF-8 mode. This bug could also
753        have affected the operation of pcre_study().
754    
755    25. Realized that a little bit of performance could be had by replacing
756        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
757    
758    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
759    
760    27. Possessive quantifiers such as a++ were previously implemented by turning
761        them into atomic groups such as ($>a+). Now they have their own opcodes,
762        which improves performance. This includes the automatically created ones
763        from 23 above.
764    
765    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
766        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
767        the first matched character to be a colon. This applied both to named and
768        numbered groups.
769    
770    29. The ucpinternal.h header file was missing its idempotency #ifdef.
771    
772    30. I was sent a "project" file called libpcre.a.dev which I understand makes
773        building PCRE on Windows easier, so I have included it in the distribution.
774    
775    31. There is now a check in pcretest against a ridiculously large number being
776        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
777        loop, the loop is abandoned.
778    
779    32. Forward references to subpatterns in conditions such as (?(2)...) where
780        subpattern 2 is defined later cause pcre_compile() to search forwards in
781        the pattern for the relevant set of parentheses. This search went wrong
782        when there were unescaped parentheses in a character class, parentheses
783        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
784    
785    33. "Subroutine" calls and backreferences were previously restricted to
786        referencing subpatterns earlier in the regex. This restriction has now
787        been removed.
788    
789    34. Added a number of extra features that are going to be in Perl 5.10. On the
790        whole, these are just syntactic alternatives for features that PCRE had
791        previously implemented using the Python syntax or my own invention. The
792        other formats are all retained for compatibility.
793    
794        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
795            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
796            also .NET compatible.
797    
798        (b) A recursion or subroutine call to a named group can now be defined as
799            (?&name) as well as (?P>name).
800    
801        (c) A backreference to a named group can now be defined as \k<name> or
802            \k'name' as well as (?P=name). The new forms, as well as being in Perl
803            5.10, are also .NET compatible.
804    
805        (d) A conditional reference to a named group can now use the syntax
806            (?(<name>) or (?('name') as well as (?(name).
807    
808        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
809            groups (named and numbered) that are never evaluated inline, but can be
810            called as "subroutines" from elsewhere. In effect, the DEFINE condition
811            is always false. There may be only one alternative in such a group.
812    
813        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
814            as the simple (?(R). The condition is true only if the most recent
815            recursion is that of the given number or name. It does not search out
816            through the entire recursion stack.
817    
818        (g) The escape \gN or \g{N} has been added, where N is a positive or
819            negative number, specifying an absolute or relative reference.
820    
821    35. Tidied to get rid of some further signed/unsigned compiler warnings and
822        some "unreachable code" warnings.
823    
824    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
825        things, this adds five new scripts.
826    
827    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
828        There were also incompatibilities regarding the handling of \Q..\E inside
829        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
830        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
831    
832    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
833        matches an empty string, and forcibly breaks the loop. There were bugs in
834        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
835        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
836        separate and independent bugs (that affected different cases) have been
837        fixed.
838    
839    39. Refactored the code to abolish the use of different opcodes for small
840        capturing bracket numbers. This is a tidy that I avoided doing when I
841        removed the limit on the number of capturing brackets for 3.5 back in 2001.
842        The new approach is not only tidier, it makes it possible to reduce the
843        memory needed to fix the previous bug (38).
844    
845    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
846        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
847        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
848        mode.
849    
850    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
851        report.
852    
853    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
854        copy construction and assignment in the C++ wrapper.
855    
856    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
857        couple of bugs that could have given wrong results in the "--newline=crlf"
858        case.
859    
860    44. Added a number of casts and did some reorganization of signed/unsigned int
861        variables following suggestions from Dair Grant. Also renamed the variable
862        "this" as "item" because it is a C++ keyword.
863    
864    45. Arranged for dftables to add
865    
866          #include "pcre_internal.h"
867    
868        to pcre_chartables.c because without it, gcc 4.x may remove the array
869        definition from the final binary if PCRE is built into a static library and
870        dead code stripping is activated.
871    
872    46. For an unanchored pattern, if a match attempt fails at the start of a
873        newline sequence, and the newline setting is CRLF or ANY, and the next two
874        characters are CRLF, advance by two characters instead of one.
875    
876    
877    Version 6.7 04-Jul-06
878    ---------------------
879    
880     1. In order to handle tests when input lines are enormously long, pcretest has
881        been re-factored so that it automatically extends its buffers when
882        necessary. The code is crude, but this _is_ just a test program. The
883        default size has been increased from 32K to 50K.
884    
885     2. The code in pcre_study() was using the value of the re argument before
886        testing it for NULL. (Of course, in any sensible call of the function, it
887        won't be NULL.)
888    
889     3. The memmove() emulation function in pcre_internal.h, which is used on
890        systems that lack both memmove() and bcopy() - that is, hardly ever -
891        was missing a "static" storage class specifier.
892    
893     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
894        containing an extended class (one that cannot be represented by a bitmap
895        because it contains high-valued characters or Unicode property items, e.g.
896        [\pZ]). Almost always one would set UTF-8 mode when processing such a
897        pattern, but PCRE should not loop if you do not (it no longer does).
898        [Detail: two cases were found: (a) a repeated subpattern containing an
899        extended class; (b) a recursive reference to a subpattern that followed a
900        previous extended class. It wasn't skipping over the extended class
901        correctly when UTF-8 mode was not set.]
902    
903     5. A negated single-character class was not being recognized as fixed-length
904        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
905        compile error "lookbehind assertion is not fixed length".
906    
907     6. The RunPerlTest auxiliary script was showing an unexpected difference
908        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
909        write a Perl script that can interpret lines of an input file either as
910        byte characters or as UTF-8, which is what "perltest" was being required to
911        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
912        can't do is switch easily at run time between having the "use utf8;" pragma
913        or not. In the end, I fudged it by using the RunPerlTest script to insert
914        "use utf8;" explicitly for the UTF-8 tests.
915    
916     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
917        the end of the subject string, contrary to the documentation and to what
918        Perl does. This was true of both matching functions. Now it matches only at
919        the start of the subject and immediately after *internal* newlines.
920    
921     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
922        a pointer to an int instead of a pointer to an unsigned long int. This
923        caused problems on 64-bit systems.
924    
925     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
926        instance of the 'standard' template library not being so standard".
927    
928    10. There was no check on the number of named subpatterns nor the maximum
929        length of a subpattern name. The product of these values is used to compute
930        the size of the memory block for a compiled pattern. By supplying a very
931        long subpattern name and a large number of named subpatterns, the size
932        computation could be caused to overflow. This is now prevented by limiting
933        the length of names to 32 characters, and the number of named subpatterns
934        to 10,000.
935    
936    11. Subpatterns that are repeated with specific counts have to be replicated in
937        the compiled pattern. The size of memory for this was computed from the
938        length of the subpattern and the repeat count. The latter is limited to
939        65535, but there was no limit on the former, meaning that integer overflow
940        could in principle occur. The compiled length of a repeated subpattern is
941        now limited to 30,000 bytes in order to prevent this.
942    
943    12. Added the optional facility to have named substrings with the same name.
944    
945    13. Added the ability to use a named substring as a condition, using the
946        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
947        are numbers (not recommended). Forward references are permitted.
948    
949    14. Added forward references in named backreferences (if you see what I mean).
950    
951    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
952        pattern could run off the end of the subject. For example, the pattern
953        "(?s)(.{1,5})"8 did this with the subject "ab".
954    
955    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
956        PCRE_CASELESS was set when matching characters that were quantified with ?
957        or *.
958    
959    17. A character class other than a single negated character that had a minimum
960        but no maximum quantifier - for example [ab]{6,} - was not handled
961        correctly by pce_dfa_exec(). It would match only one character.
962    
963    18. A valid (though odd) pattern that looked like a POSIX character
964        class but used an invalid character after [ (for example [[,abc,]]) caused
965        pcre_compile() to give the error "Failed: internal error: code overflow" or
966        in some cases to crash with a glibc free() error. This could even happen if
967        the pattern terminated after [[ but there just happened to be a sequence of
968        letters, a binary zero, and a closing ] in the memory that followed.
969    
970    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
971        over the years. Originally (before any Unicode support), just the bottom 8
972        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
973        output from "man perlunicode" includes this:
974    
975          The regular expression compiler produces polymorphic opcodes.  That
976          is, the pattern adapts to the data and automatically switches to
977          the Unicode character scheme when presented with Unicode data--or
978          instead uses a traditional byte scheme when presented with byte
979          data.
980    
981        Sadly, a wide octal escape does not cause a switch, and in a string with
982        no other multibyte characters, these octal escapes are treated as before.
983        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
984        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
985        Unicode string.
986    
987        I have not perpetrated such confusion in PCRE. Up till now, it took just
988        the bottom 8 bits, as in old Perl. I have now made octal escapes with
989        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
990        translate to the appropriate multibyte character.
991    
992    29. Applied some refactoring to reduce the number of warnings from Microsoft
993        and Borland compilers. This has included removing the fudge introduced
994        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
995        a warning about an unused variable.
996    
997    21. PCRE has not included VT (character 0x0b) in the set of whitespace
998        characters since release 4.0, because Perl (from release 5.004) does not.
999        [Or at least, is documented not to: some releases seem to be in conflict
1000        with the documentation.] However, when a pattern was studied with
1001        pcre_study() and all its branches started with \s, PCRE still included VT
1002        as a possible starting character. Of course, this did no harm; it just
1003        caused an unnecessary match attempt.
1004    
1005    22. Removed a now-redundant internal flag bit that recorded the fact that case
1006        dependency changed within the pattern. This was once needed for "required
1007        byte" processing, but is no longer used. This recovers a now-scarce options
1008        bit. Also moved the least significant internal flag bit to the most-
1009        significant bit of the word, which was not previously used (hangover from
1010        the days when it was an int rather than a uint) to free up another bit for
1011        the future.
1012    
1013    23. Added support for CRLF line endings as well as CR and LF. As well as the
1014        default being selectable at build time, it can now be changed at runtime
1015        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1016        specify that it is scanning data with non-default line endings.
1017    
1018    24. Changed the definition of CXXLINK to make it agree with the definition of
1019        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1020    
1021    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1022        recursions. This makes a big different to stack usage for some patterns.
1023    
1024    26. If a subpattern containing a named recursion or subroutine reference such
1025        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1026        the space required for the compiled pattern went wrong and gave too small a
1027        value. Depending on the environment, this could lead to "Failed: internal
1028        error: code overflow at offset 49" or "glibc detected double free or
1029        corruption" errors.
1030    
1031    27. Applied patches from Google (a) to support the new newline modes and (b) to
1032        advance over multibyte UTF-8 characters in GlobalReplace.
1033    
1034    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1035        difference for some implementation of PCRE in some Windows version.
1036    
1037    29. Added some extra testing facilities to pcretest:
1038    
1039        \q<number>   in a data line sets the "match limit" value
1040        \Q<number>   in a data line sets the "match recursion limt" value
1041        -S <number>  sets the stack size, where <number> is in megabytes
1042    
1043        The -S option isn't available for Windows.
1044    
1045    
1046    Version 6.6 06-Feb-06
1047    ---------------------
1048    
1049     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1050        in pcreposix.h. I have copied the definition from pcre.h.
1051    
1052     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1053        because pcre.h is no longer a built file.
1054    
1055     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1056        not normally included in the compiled code.
1057    
1058    
1059    Version 6.5 01-Feb-06
1060    ---------------------
1061    
1062     1. When using the partial match feature with pcre_dfa_exec(), it was not
1063        anchoring the second and subsequent partial matches at the new starting
1064        point. This could lead to incorrect results. For example, with the pattern
1065        /1234/, partially matching against "123" and then "a4" gave a match.
1066    
1067     2. Changes to pcregrep:
1068    
1069        (a) All non-match returns from pcre_exec() were being treated as failures
1070            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1071            error message is output. Some extra information is given for the
1072            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1073            probably the only errors that are likely to be caused by users (by
1074            specifying a regex that has nested indefinite repeats, for instance).
1075            If there are more than 20 of these errors, pcregrep is abandoned.
1076    
1077        (b) A binary zero was treated as data while matching, but terminated the
1078            output line if it was written out. This has been fixed: binary zeroes
1079            are now no different to any other data bytes.
1080    
1081        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1082            used to set a locale for matching. The --locale=xxxx long option has
1083            been added (no short equivalent) to specify a locale explicitly on the
1084            pcregrep command, overriding the environment variables.
1085    
1086        (d) When -B was used with -n, some line numbers in the output were one less
1087            than they should have been.
1088    
1089        (e) Added the -o (--only-matching) option.
1090    
1091        (f) If -A or -C was used with -c (count only), some lines of context were
1092            accidentally printed for the final match.
1093    
1094        (g) Added the -H (--with-filename) option.
1095    
1096        (h) The combination of options -rh failed to suppress file names for files
1097            that were found from directory arguments.
1098    
1099        (i) Added the -D (--devices) and -d (--directories) options.
1100    
1101        (j) Added the -F (--fixed-strings) option.
1102    
1103        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1104    
1105        (l) Added the --colo(u)r option.
1106    
1107        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1108            is not present by default.
1109    
1110     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1111        items such as (?R) or (?1), when the recursion could match a number of
1112        alternatives. If it matched one of the alternatives, but subsequently,
1113        outside the recursion, there was a failure, the code tried to back up into
1114        the recursion. However, because of the way PCRE is implemented, this is not
1115        possible, and the result was an incorrect result from the match.
1116    
1117        In order to prevent this happening, the specification of recursion has
1118        been changed so that all such subpatterns are automatically treated as
1119        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1120    
1121     4. I had overlooked the fact that, in some locales, there are characters for
1122        which isalpha() is true but neither isupper() nor islower() are true. In
1123        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1124        and ordfeminine) are like this. This affected the treatment of \w and \W
1125        when they appeared in character classes, but not when they appeared outside
1126        a character class. The bit map for "word" characters is now created
1127        separately from the results of isalnum() instead of just taking it from the
1128        upper, lower, and digit maps. (Plus the underscore character, of course.)
1129    
1130     5. The above bug also affected the handling of POSIX character classes such as
1131        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1132        permanent tables. Instead, the bit maps for such a class were previously
1133        created as the appropriate unions of the upper, lower, and digit bitmaps.
1134        Now they are created by subtraction from the [[:word:]] class, which has
1135        its own bitmap.
1136    
1137     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1138        It is created by subtracting the vertical space characters (\x09, \x0a,
1139        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1140        subtraction was done in the overall bitmap for a character class, meaning
1141        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1142        be recognized. This bug has been fixed.
1143    
1144     7. Patches from the folks at Google:
1145    
1146          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1147          real life, but is still worth protecting against".
1148    
1149          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1150          regular expressions".
1151    
1152          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1153          have it.
1154    
1155          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1156          "configure" and the latter not, in order to fix a problem somebody had
1157          with compiling the Arg class on HP-UX.
1158    
1159          (e) Improve the error-handling of the C++ wrapper a little bit.
1160    
1161          (f) New tests for checking recursion limiting.
1162    
1163     8. The pcre_memmove() function, which is used only if the environment does not
1164        have a standard memmove() function (and is therefore rarely compiled),
1165        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1166        returning a result (though PCRE never actually uses the result).
1167    
1168     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1169        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1170        returned instead of calling malloc() with an overflowing number that would
1171        most likely cause subsequent chaos.
1172    
1173    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1174    
1175    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1176        with this option is matched, the nmatch and pmatch options of regexec() are
1177        ignored.
1178    
1179    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1180        provided in case anyone wants to the the POSIX interface with UTF-8
1181        strings.
1182    
1183    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1184        C++ linking (needed for some HP-UX environments).
1185    
1186    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1187        (unused parameter) and in the pcre_printint() function (omitted "default"
1188        switch label when the default is to do nothing).
1189    
1190    15. Added some code to make it possible, when PCRE is compiled as a C++
1191        library, to replace subject pointers for pcre_exec() with a smart pointer
1192        class, thus making it possible to process discontinuous strings.
1193    
1194    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1195        much the same function. They were added by different people who were trying
1196        to make PCRE easy to compile on non-Unix systems. It has been suggested
1197        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1198        for compiling on Windows systems. I have therefore replaced it with
1199        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1200        defaults to "extern" for C or "extern C" for C++, which works fine on
1201        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1202        SCOPE with something explicit in config.h. In addition:
1203    
1204        (a) pcreposix.h still had just "extern" instead of either of these macros;
1205            I have replaced it with PCRE_DATA_SCOPE.
1206    
1207        (b) Functions such as _pcre_xclass(), which are internal to the library,
1208            but external in the C sense, all had PCRE_EXPORT in their definitions.
1209            This is apparently wrong for the Windows case, so I have removed it.
1210            (It makes no difference on Unix-like systems.)
1211    
1212    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1213        of recursive calls to match(). This is different to MATCH_LIMIT because
1214        that limits the total number of calls to match(), not all of which increase
1215        the depth of recursion. Limiting the recursion depth limits the amount of
1216        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1217        when PCRE is compiled, and changed at run time. A patch from Google adds
1218        this functionality to the C++ interface.
1219    
1220    18. Changes to the handling of Unicode character properties:
1221    
1222        (a) Updated the table to Unicode 4.1.0.
1223    
1224        (b) Recognize characters that are not in the table as "Cn" (undefined).
1225    
1226        (c) I revised the way the table is implemented to a much improved format
1227            which includes recognition of ranges. It now supports the ranges that
1228            are defined in UnicodeData.txt, and it also amalgamates other
1229            characters into ranges. This has reduced the number of entries in the
1230            table from around 16,000 to around 3,000, thus reducing its size
1231            considerably. I realized I did not need to use a tree structure after
1232            all - a binary chop search is just as efficient. Having reduced the
1233            number of entries, I extended their size from 6 bytes to 8 bytes to
1234            allow for more data.
1235    
1236        (d) Added support for Unicode script names via properties such as \p{Han}.
1237    
1238    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1239        matching that character.
1240    
1241    20. When matching a repeated Unicode property with a minimum greater than zero,
1242        (for example \pL{2,}), PCRE could look past the end of the subject if it
1243        reached it while seeking the minimum number of characters. This could
1244        happen only if some of the characters were more than one byte long, because
1245        there is a check for at least the minimum number of bytes.
1246    
1247    21. Refactored the implementation of \p and \P so as to be more general, to
1248        allow for more different types of property in future. This has changed the
1249        compiled form incompatibly. Anybody with saved compiled patterns that use
1250        \p or \P will have to recompile them.
1251    
1252    22. Added "Any" and "L&" to the supported property types.
1253    
1254    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1255        but give a compile time error if the value is greater than 0xff.
1256    
1257    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1258        accidentally not being installed or uninstalled.
1259    
1260    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1261        made were to insert the current release number. This seemed silly, because
1262        it made things harder for people building PCRE on systems that don't run
1263        "configure". I have turned pcre.h into a distributed file, no longer built
1264        by "configure", with the version identification directly included. There is
1265        no longer a pcre.h.in file.
1266    
1267        However, this change necessitated a change to the pcre-config script as
1268        well. It is built from pcre-config.in, and one of the substitutions was the
1269        release number. I have updated configure.ac so that ./configure now finds
1270        the release number by grepping pcre.h.
1271    
1272    26. Added the ability to run the tests under valgrind.
1273    
1274    
1275    Version 6.4 05-Sep-05
1276    ---------------------
1277    
1278     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1279        "--" to be printed when multiple files were scanned, even when none of the
1280        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1281        consider it to be a bug, and have restored the previous behaviour.
1282    
1283     2. A couple of code tidies to get rid of compiler warnings.
1284    
1285     3. The pcretest program used to cheat by referring to symbols in the library
1286        whose names begin with _pcre_. These are internal symbols that are not
1287        really supposed to be visible externally, and in some environments it is
1288        possible to suppress them. The cheating is now confined to including
1289        certain files from the library's source, which is a bit cleaner.
1290    
1291     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1292        file's purpose clearer.
1293    
1294     5. Reorganized pcre_ucp_findchar().
1295    
1296    
1297    Version 6.3 15-Aug-05
1298    ---------------------
1299    
1300     1. The file libpcre.pc.in did not have general read permission in the tarball.
1301    
1302     2. There were some problems when building without C++ support:
1303    
1304        (a) If C++ support was not built, "make install" and "make test" still
1305            tried to test it.
1306    
1307        (b) There were problems when the value of CXX was explicitly set. Some
1308            changes have been made to try to fix these, and ...
1309    
1310        (c) --disable-cpp can now be used to explicitly disable C++ support.
1311    
1312        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1313            backslash in a target when C++ was disabled. This confuses some
1314            versions of "make", apparently. Using an intermediate variable solves
1315            this. (Same for CPP_LOBJ.)
1316    
1317     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1318        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1319        necessary on certain architectures.
1320    
1321     4. Added a setting of -export-symbols-regex to the link command to remove
1322        those symbols that are exported in the C sense, but actually are local
1323        within the library, and not documented. Their names all begin with
1324        "_pcre_". This is not a perfect job, because (a) we have to except some
1325        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1326        available (and never for static libraries). I have made a note to try to
1327        find a way round (a) in the future.
1328    
1329    
1330    Version 6.2 01-Aug-05
1331    ---------------------
1332    
1333     1. There was no test for integer overflow of quantifier values. A construction
1334        such as {1111111111111111} would give undefined results. What is worse, if
1335        a minimum quantifier for a parenthesized subpattern overflowed and became
1336        negative, the calculation of the memory size went wrong. This could have
1337        led to memory overwriting.
1338    
1339     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1340    
1341     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1342        operating environments where this matters.
1343    
1344     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1345        PCRE options from within the C++ wrapper.
1346    
1347     5. Named capturing subpatterns were not being correctly counted when a pattern
1348        was compiled. This caused two problems: (a) If there were more than 100
1349        such subpatterns, the calculation of the memory needed for the whole
1350        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1351        back references of the form \12, where the number was greater than 9, were
1352        not recognized as back references, even though there were sufficient
1353        previous subpatterns.
1354    
1355     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1356        versions of gcc, e.g. 2.95.4.
1357    
1358    
1359    Version 6.1 21-Jun-05
1360    ---------------------
1361    
1362     1. There was one reference to the variable "posix" in pcretest.c that was not
1363        surrounded by "#if !defined NOPOSIX".
1364    
1365     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1366        the cross-check on the old pcre_info() function, for the benefit of the
1367        cut-down version of PCRE that is currently imported into Exim.
1368    
1369     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1370        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1371        patterns that start (?i) but I don't think that matters. The use of (?i) is
1372        just an example; this all applies to the other options as well.
1373    
1374     4. Since libtool seems to echo the compile commands it is issuing, the output
1375        from "make" can be reduced a bit by putting "@" in front of each libtool
1376        compile command.
1377    
1378     5. Patch from the folks at Google for configure.in to be a bit more thorough
1379        in checking for a suitable C++ installation before trying to compile the
1380        C++ stuff. This should fix a reported problem when a compiler was present,
1381        but no suitable headers.
1382    
1383     6. The man pages all had just "PCRE" as their title. I have changed them to
1384        be the relevant file name. I have also arranged that these names are
1385        retained in the file doc/pcre.txt, which is a concatenation in text format
1386        of all the man pages except the little individual ones for each function.
1387    
1388     7. The NON-UNIX-USE file had not been updated for the different set of source
1389        files that come with release 6. I also added a few comments about the C++
1390        wrapper.
1391    
1392    
1393    Version 6.0 07-Jun-05
1394    ---------------------
1395    
1396     1. Some minor internal re-organization to help with my DFA experiments.
1397    
1398     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1399        didn't matter for the library itself when fully configured, but did matter
1400        when compiling without UCP support, or within Exim, where the ucp files are
1401        not imported.
1402    
1403     3. Refactoring of the library code to split up the various functions into
1404        different source modules. The addition of the new DFA matching code (see
1405        below) to a single monolithic source would have made it really too
1406        unwieldy, quite apart from causing all the code to be include in a
1407        statically linked application, when only some functions are used. This is
1408        relevant even without the DFA addition now that patterns can be compiled in
1409        one application and matched in another.
1410    
1411        The downside of splitting up is that there have to be some external
1412        functions and data tables that are used internally in different modules of
1413        the library but which are not part of the API. These have all had their
1414        names changed to start with "_pcre_" so that they are unlikely to clash
1415        with other external names.
1416    
1417     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1418        a different (DFA) algorithm. Although it is slower than the original
1419        function, it does have some advantages for certain types of matching
1420        problem.
1421    
1422     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1423        including restarting after a partial match.
1424    
1425     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1426        defined when compiling for Windows was sent to me. I have put it into the
1427        code, though I have no means of testing or verifying it.
1428    
1429     7. Added the pcre_refcount() auxiliary function.
1430    
1431     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1432        match before or at the first newline in the subject string. In pcretest,
1433        the /f option on a pattern can be used to set this.
1434    
1435     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1436        would behave wrongly. This has been present in PCRE since release 4.0.
1437    
1438    10. A number of changes to the pcregrep command:
1439    
1440        (a) Refactored how -x works; insert ^(...)$ instead of setting
1441            PCRE_ANCHORED and checking the length, in preparation for adding
1442            something similar for -w.
1443    
1444        (b) Added the -w (match as a word) option.
1445    
1446        (c) Refactored the way lines are read and buffered so as to have more
1447            than one at a time available.
1448    
1449        (d) Implemented a pcregrep test script.
1450    
1451        (e) Added the -M (multiline match) option. This allows patterns to match
1452            over several lines of the subject. The buffering ensures that at least
1453            8K, or the rest of the document (whichever is the shorter) is available
1454            for matching (and similarly the previous 8K for lookbehind assertions).
1455    
1456        (f) Changed the --help output so that it now says
1457    
1458              -w, --word-regex(p)
1459    
1460            instead of two lines, one with "regex" and the other with "regexp"
1461            because that confused at least one person since the short forms are the
1462            same. (This required a bit of code, as the output is generated
1463            automatically from a table. It wasn't just a text change.)
1464    
1465        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1466            option but starts with a hyphen. Could be a pattern or a path name
1467            starting with a hyphen, for instance.
1468    
1469        (h) "-" can be given as a file name to represent stdin.
1470    
1471        (i) When file names are being printed, "(standard input)" is used for
1472            the standard input, for compatibility with GNU grep. Previously
1473            "<stdin>" was used.
1474    
1475        (j) The option --label=xxx can be used to supply a name to be used for
1476            stdin when file names are being printed. There is no short form.
1477    
1478        (k) Re-factored the options decoding logic because we are going to add
1479            two more options that take data. Such options can now be given in four
1480            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1481    
1482        (l) Added the -A, -B, and -C options for requesting that lines of context
1483            around matches be printed.
1484    
1485        (m) Added the -L option to print the names of files that do not contain
1486            any matching lines, that is, the complement of -l.
1487    
1488        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1489            continue to scan other files.
1490    
1491        (o) The -s option was incorrectly implemented. For compatibility with other
1492            greps, it now suppresses the error message for a non-existent or non-
1493            accessible file (but not the return code). There is a new option called
1494            -q that suppresses the output of matching lines, which was what -s was
1495            previously doing.
1496    
1497        (p) Added --include and --exclude options to specify files for inclusion
1498            and exclusion when recursing.
1499    
1500    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1501        Hopefully, it now does.
1502    
1503    12. Missing cast in pcre_study().
1504    
1505    13. Added an "uninstall" target to the makefile.
1506    
1507    14. Replaced "extern" in the function prototypes in Makefile.in with
1508        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1509        world, but is set differently for Windows.
1510    
1511    15. Added a second compiling function called pcre_compile2(). The only
1512        difference is that it has an extra argument, which is a pointer to an
1513        integer error code. When there is a compile-time failure, this is set
1514        non-zero, in addition to the error test pointer being set to point to an
1515        error message. The new argument may be NULL if no error number is required
1516        (but then you may as well call pcre_compile(), which is now just a
1517        wrapper). This facility is provided because some applications need a
1518        numeric error indication, but it has also enabled me to tidy up the way
1519        compile-time errors are handled in the POSIX wrapper.
1520    
1521    16. Added VPATH=.libs to the makefile; this should help when building with one
1522        prefix path and installing with another. (Or so I'm told by someone who
1523        knows more about this stuff than I do.)
1524    
1525    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1526        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1527        match everything, including newlines. This is not POSIX-compatible, but
1528        somebody wanted the feature. From pcretest it can be activated by using
1529        both the P and the s flags.
1530    
1531    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1532    
1533    19. libpcre.pc was being incorrectly installed as executable.
1534    
1535    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1536        it now also looks for '\r' so that it will work unmodified on Windows.
1537    
1538    21. Added Google's contributed C++ wrapper to the distribution.
1539    
1540    22. Added some untidy missing memory free() calls in pcretest, to keep
1541        Electric Fence happy when testing.
1542    
1543    
1544    
1545    Version 5.0 13-Sep-04
1546    ---------------------
1547    
1548     1. Internal change: literal characters are no longer packed up into items
1549        containing multiple characters in a single byte-string. Each character
1550        is now matched using a separate opcode. However, there may be more than one
1551        byte in the character in UTF-8 mode.
1552    
1553     2. The pcre_callout_block structure has two new fields: pattern_position and
1554        next_item_length. These contain the offset in the pattern to the next match
1555        item, and its length, respectively.
1556    
1557     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1558        insertion of callouts before each pattern item. Added the /C option to
1559        pcretest to make use of this.
1560    
1561     4. On the advice of a Windows user, the lines
1562    
1563          #if defined(_WIN32) || defined(WIN32)
1564          _setmode( _fileno( stdout ), 0x8000 );
1565          #endif  /* defined(_WIN32) || defined(WIN32) */
1566    
1567        have been added to the source of pcretest. This apparently does useful
1568        magic in relation to line terminators.
1569    
1570     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1571        for the benefit of those environments where the "b" makes a difference.
1572    
1573     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1574        to know about it. I have put a hack into configure.in that adds in code
1575        to set GCC=yes if CC=icc. This seems to end up at a point in the
1576        generated configure script that is early enough to affect the setting of
1577        compiler options, which is what is needed, but I have no means of testing
1578        whether it really works. (The user who reported this had patched the
1579        generated configure script, which of course I cannot do.)
1580    
1581        LATER: After change 22 below (new libtool files), the configure script
1582        seems to know about icc (and also ecc). Therefore, I have commented out
1583        this hack in configure.in.
1584    
1585     7. Added support for pkg-config (2 patches were sent in).
1586    
1587     8. Negated POSIX character classes that used a combination of internal tables
1588        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1589        [[:^ascii]]. Typically, they would match almost any characters. The other
1590        POSIX classes were not broken in this way.
1591    
1592     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1593        to find the match, as PCRE was deluded into thinking that the match had to
1594        start at the start point or following a newline. The same bug applied to
1595        patterns with negative forward assertions or any backward assertions
1596        preceding ".*" at the start, unless the pattern required a fixed first
1597        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1598    
1599    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1600        starting at the last subject character, bytes beyond the end of the subject
1601        string were read.
1602    
1603    11. Renamed the variable "class" as "classbits" to make life easier for C++
1604        users. (Previously there was a macro definition, but it apparently wasn't
1605        enough.)
1606    
1607    12. Added the new field "tables" to the extra data so that tables can be passed
1608        in at exec time, or the internal tables can be re-selected. This allows
1609        a compiled regex to be saved and re-used at a later time by a different
1610        program that might have everything at different addresses.
1611    
1612    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1613        -R library as well as a -L library.
1614    
1615    14. The debugging options of pcretest (-d on the command line or D on a
1616        pattern) showed incorrect output for anything following an extended class
1617        that contained multibyte characters and which was followed by a quantifier.
1618    
1619    15. Added optional support for general category Unicode character properties
1620        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1621        support. It adds about 90K to the size of the library. The meanings of the
1622        inbuilt class escapes such as \d and \s have NOT been changed.
1623    
1624    16. Updated pcredemo.c to include calls to free() to release the memory for the
1625        compiled pattern.
1626    
1627    17. The generated file chartables.c was being created in the source directory
1628        instead of in the building directory. This caused the build to fail if the
1629        source directory was different from the building directory, and was
1630        read-only.
1631    
1632    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1633        file. No doubt somebody will tell me if they don't make sense... Also added
1634        Dan Mooney's comments about building on OpenVMS.
1635    
1636    19. Added support for partial matching via the PCRE_PARTIAL option for
1637        pcre_exec() and the \P data escape in pcretest.
1638    
1639    20. Extended pcretest with 3 new pattern features:
1640    
1641        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1642              write the compiled pattern to the file whose name is "rest-of-line".
1643              This is a straight binary dump of the data, with the saved pointer to
1644              the character tables forced to be NULL. The study data, if any, is
1645              written too. After writing, pcretest reads a new pattern.
1646    
1647        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1648              compiled pattern from the given file. There must not be any
1649              occurrences of "<" in the file name (pretty unlikely); if there are,
1650              pcretest will instead treat the initial "<" as a pattern delimiter.
1651              After reading in the pattern, pcretest goes on to read data lines as
1652              usual.
1653    
1654        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1655              and 16-bit fields in a compiled pattern, to simulate a pattern that
1656              was compiled on a host of opposite endianness.
1657    
1658    21. The pcre-exec() function can now cope with patterns that were compiled on
1659        hosts of opposite endianness, with this restriction:
1660    
1661          As for any compiled expression that is saved and used later, the tables
1662          pointer field cannot be preserved; the extra_data field in the arguments
1663          to pcre_exec() should be used to pass in a tables address if a value
1664          other than the default internal tables were used at compile time.
1665    
1666    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1667        now diagnosed as an error. Previously, most of the time, a negative number
1668        would have been treated as zero, but if in addition "ovector" was passed as
1669        NULL, a crash could occur.
1670    
1671    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1672        new versions from the libtool 1.5 distribution (the last one is a copy of
1673        a file called libtool.m4). This seems to have fixed the need to patch
1674        "configure" to support Darwin 1.3 (which I used to do). However, I still
1675        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1676        workstation).
1677    
1678    24. Changed the PCRE licence to be the more standard "BSD" licence.
1679    
1680    
1681    Version 4.5 01-Dec-03
1682    ---------------------
1683    
1684     1. There has been some re-arrangement of the code for the match() function so
1685        that it can be compiled in a version that does not call itself recursively.
1686        Instead, it keeps those local variables that need separate instances for
1687        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1688        needs to "recurse". Keeping track of where control must go is done by means
1689        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1690        hide most of the details from the main code, and operates only if
1691        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1692        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1693        operating.
1694    
1695        To make it easier for callers to provide specially tailored get/free
1696        functions for this usage, two new functions, pcre_stack_malloc, and
1697        pcre_stack_free, are used. They are always called in strict stacking order,
1698        and the size of block requested is always the same.
1699    
1700        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1701        PCRE has been compiled to use the stack or the heap for recursion. The
1702        -C option of pcretest uses this to show which version is compiled.
1703    
1704        A new data escape \S, is added to pcretest; it causes the amounts of store
1705        obtained and freed by both kinds of malloc/free at match time to be added
1706        to the output.
1707    
1708     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1709        what's available on my current Linux desktop machine.
1710    
1711     3. When matching a UTF-8 string, the test for a valid string at the start has
1712        been extended. If start_offset is not zero, PCRE now checks that it points
1713        to a byte that is the start of a UTF-8 character. If not, it returns
1714        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1715        this is necessary because there may be backward assertions in the pattern.
1716        When matching the same subject several times, it may save resources to use
1717        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1718    
1719     4. The code for checking the validity of UTF-8 strings has been tightened so
1720        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1721        containing "overlong sequences".
1722    
1723     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1724        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1725        should have been "&", but it just so happened that all the cases this let
1726        through by mistake were picked up later in the function.
1727    
1728     6. I had used a variable called "isblank" - this is a C99 function, causing
1729        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1730    
1731     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1732        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1733        so the version is shown; (c) stop "make test" echoing "./RunTest".
1734    
1735     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1736    
1737     9. The prototype for memmove() for systems that don't have it was using
1738        size_t, but the inclusion of the header that defines size_t was later. I've
1739        moved the #includes for the C headers earlier to avoid this.
1740    
1741    10. Added some adjustments to the code to make it easier to compiler on certain
1742        special systems:
1743    
1744          (a) Some "const" qualifiers were missing.
1745          (b) Added the macro EXPORT before all exported functions; by default this
1746              is defined to be empty.
1747          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1748              that it reads its output file name as an argument instead of writing
1749              to the standard output and assuming this can be redirected.
1750    
1751    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1752        class containing characters with values greater than 255, PCRE compilation
1753        went into a loop.
1754    
1755    12. A recursive reference to a subpattern that was within another subpattern
1756        that had a minimum quantifier of zero caused PCRE to crash. For example,
1757        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1758        recursion. If the recursively-called subpattern itself had a zero repeat,
1759        that was OK.
1760    
1761    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1762        buffer into which it was copied (for escape processing) was still set at
1763        1024, so long lines caused crashes.
1764    
1765    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1766        "internal error: code overflow...". This applied to any character class
1767        that was followed by a possessive quantifier.
1768    
1769    15. Modified the Makefile to add libpcre.la as a prerequisite for
1770        libpcreposix.la because I was told this is needed for a parallel build to
1771        work.
1772    
1773    16. If a pattern that contained .* following optional items at the start was
1774        studied, the wrong optimizing data was generated, leading to matching
1775        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1776        matching string must start with a or b or c. The correct conclusion for
1777        this pattern is that a match can start with any character.
1778    
1779    
1780    Version 4.4 13-Aug-03
1781    ---------------------
1782    
1783     1. In UTF-8 mode, a character class containing characters with values between
1784        127 and 255 was not handled correctly if the compiled pattern was studied.
1785        In fixing this, I have also improved the studying algorithm for such
1786        classes (slightly).
1787    
1788     2. Three internal functions had redundant arguments passed to them. Removal
1789        might give a very teeny performance improvement.
1790    
1791     3. Documentation bug: the value of the capture_top field in a callout is *one
1792        more than* the number of the hightest numbered captured substring.
1793    
1794     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1795        in incorrectly linking with a previously installed version. They now link
1796        explicitly with libpcre.la.
1797    
1798     5. configure.in no longer needs to recognize Cygwin specially.
1799    
1800     6. A problem in pcre.in for Windows platforms is fixed.
1801    
1802     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1803        pcretest, it used to include the size of the study block as part of its
1804        output. Unfortunately, the structure contains a field that has a different
1805        size on different hardware architectures. This meant that the tests that
1806        showed this size failed. As the block is currently always of a fixed size,
1807        this information isn't actually particularly useful in pcretest output, so
1808        I have just removed it.
1809    
1810     8. Three pre-processor statements accidentally did not start in column 1.
1811        Sadly, there are *still* compilers around that complain, even though
1812        standard C has not required this for well over a decade. Sigh.
1813    
1814     9. In pcretest, the code for checking callouts passed small integers in the
1815        callout_data field, which is a void * field. However, some picky compilers
1816        complained about the casts involved for this on 64-bit systems. Now
1817        pcretest passes the address of the small integer instead, which should get
1818        rid of the warnings.
1819    
1820    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1821        both compile and run time, and gives an error if an invalid UTF-8 sequence
1822        is found. There is a option for disabling this check in cases where the
1823        string is known to be correct and/or the maximum performance is wanted.
1824    
1825    11. In response to a bug report, I changed one line in Makefile.in from
1826    
1827            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1828        to
1829            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1830    
1831        to look similar to other lines, but I have no way of telling whether this
1832        is the right thing to do, as I do not use Windows. No doubt I'll get told
1833        if it's wrong...
1834    
1835    
1836    Version 4.3 21-May-03
1837    ---------------------
1838    
1839    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1840       Makefile.
1841    
1842    2. Some refactoring to improve the quality of the code:
1843    
1844       (i)   The utf8_table... variables are now declared "const".
1845    
1846       (ii)  The code for \cx, which used the "case flipping" table to upper case
1847             lower case letters, now just substracts 32. This is ASCII-specific,
1848             but the whole concept of \cx is ASCII-specific, so it seems
1849             reasonable.
1850    
1851       (iii) PCRE was using its character types table to recognize decimal and
1852             hexadecimal digits in the pattern. This is silly, because it handles
1853             only 0-9, a-f, and A-F, but the character types table is locale-
1854             specific, which means strange things might happen. A private
1855             table is now used for this - though it costs 256 bytes, a table is
1856             much faster than multiple explicit tests. Of course, the standard
1857             character types table is still used for matching digits in subject
1858             strings against \d.
1859    
1860       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1861             ending in _t are). So I've renamed it as ESC_tee.
1862    
1863    3. The first argument for regexec() in the POSIX wrapper should have been
1864       defined as "const".
1865    
1866    4. Changed pcretest to use malloc() for its buffers so that they can be
1867       Electric Fenced for debugging.
1868    
1869    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1870       to read one or more bytes before the start of the subject string. Often this
1871       had no effect on PCRE's behaviour, but in some circumstances it could
1872       provoke a segmentation fault.
1873    
1874    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1875       to try to read one or more bytes before the start of the subject string.
1876    
1877    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1878       UTF-8 support could misbehave in various ways if the subject string
1879       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1880       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1881       back over UTF-8 characters.)
1882    
1883    
1884    Version 4.2 14-Apr-03
1885    ---------------------
1886    
1887    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1888    
1889    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1890         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1891         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1892         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1893         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1894           and BUILD_EXEEXT
1895         Note: automatic setting of the BUILD variables is not yet working
1896         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1897           compile-time but not at link-time
1898         [LINK]: use for linking executables only
1899         make different versions for Windows and non-Windows
1900         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1901           libraries
1902         [LINK_FOR_BUILD]: new variable
1903         [OBJEXT]: use throughout
1904         [EXEEXT]: use throughout
1905         <winshared>: new target
1906         <wininstall>: new target
1907         <dftables.o>: use native compiler
1908         <dftables>: use native linker
1909         <install>: handle Windows platform correctly
1910         <clean>: ditto
1911         <check>: ditto
1912         copy DLL to top builddir before testing
1913    
1914       As part of these changes, -no-undefined was removed again. This was reported
1915       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1916       in any case.
1917    
1918    3. Some tidies to get rid of compiler warnings:
1919    
1920       . In the match_data structure, match_limit was an unsigned long int, whereas
1921         match_call_count was an int. I've made them both unsigned long ints.
1922    
1923       . In pcretest the fact that a const uschar * doesn't automatically cast to
1924         a void * provoked a warning.
1925    
1926       . Turning on some more compiler warnings threw up some "shadow" variables
1927         and a few more missing casts.
1928    
1929    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1930       option, a class that contained a single character with a value between 128
1931       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1932    
1933    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1934       option, a class that contained several characters, but with at least one
1935       whose value was between 128 and 255 caused PCRE to crash.
1936    
1937    
1938    Version 4.1 12-Mar-03
1939    ---------------------
1940    
1941    1. Compiling with gcc -pedantic found a couple of places where casts were
1942    needed, and a string in dftables.c that was longer than standard compilers are
1943    required to support.
1944    
1945    2. Compiling with Sun's compiler found a few more places where the code could
1946    be tidied up in order to avoid warnings.
1947    
1948    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1949    first of these names is deprecated in the latest Autoconf in favour of the name
1950    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1951    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1952    analogy I have changed it to CFLAGS_FOR_BUILD.
1953    
1954    4. Added -no-undefined to the linking command in the Makefile, because this is
1955    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1956    linking step for the pcreposix library.
1957    
1958    5. PCRE was failing to diagnose the case of two named groups with the same
1959    name.
1960    
1961    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1962    literal character that is needed in the subject for a match, and scans along to
1963    ensure that it is present before embarking on the full matching process. This
1964    saves time in cases of nested unlimited repeats that are never going to match.
1965    Problem: the scan can take a lot of time if the subject is very long (e.g.
1966    megabytes), thus penalizing straightforward matches. It is now done only if the
1967    amount of subject to be scanned is less than 1000 bytes.
1968    
1969    7. A lesser problem with the same optimization is that it was recording the
1970    first character of an anchored pattern as "needed", thus provoking a search
1971    right along the subject, even when the first match of the pattern was going to
1972    fail. The "needed" character is now not set for anchored patterns, unless it
1973    follows something in the pattern that is of non-fixed length. Thus, it still
1974    fulfils its original purpose of finding quick non-matches in cases of nested
1975    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1976    
1977    
1978    Version 4.0 17-Feb-03
1979    ---------------------
1980    
1981    1. If a comment in an extended regex that started immediately after a meta-item
1982    extended to the end of string, PCRE compiled incorrect data. This could lead to
1983    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1984    
1985    2. Moved to autoconf 2.53 and libtool 1.4.2.
1986    
1987    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1988    the special perltest8 script is no longer needed - all the tests can be run
1989    from a single perltest script.
1990    
1991    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1992    by \s. It has now been removed in PCRE. This means it isn't recognized as
1993    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1994    class [:space:] *does* include VT, thereby creating a mess.
1995    
1996    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1997    space and tab.
1998    
1999    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2000    its new features into the main test script, reducing the number of scripts.
2001    
2002    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2003    were backward compatible, and made the (?i) apply to the whole pattern, as if
2004    /i were given. Now it behaves more logically, and applies the option setting
2005    only to what follows. PCRE has been changed to follow suit. However, if it
2006    finds options settings right at the start of the pattern, it extracts them into
2007    the global options, as before. Thus, they show up in the info data.
2008    
2009    8. Added support for the \Q...\E escape sequence. Characters in between are
2010    treated as literals. This is slightly different from Perl in that $ and @ are
2011    also handled as literals inside the quotes. In Perl, they will cause variable
2012    interpolation. Note the following examples:
2013    
2014        Pattern            PCRE matches      Perl matches
2015    
2016        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2017        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2018        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2019    
2020    For compatibility with Perl, \Q...\E sequences are recognized inside character
2021    classes as well as outside them.
2022    
2023    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2024    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2025    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2026    signed/unsigned warnings.
2027    
2028    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2029    option for pcretest, so I've replaced it by a simple function that does just
2030    that job.
2031    
2032    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2033    "pcregrep -".
2034    
2035    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2036    Java package. This provides some syntactic sugar for simple cases of what my
2037    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2038    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2039    item, you can use this simplified notation. Note that only makes sense with
2040    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2041    greediness, whatever the setting of the PCRE_UNGREEDY option.
2042    
2043    13. A change of greediness default within a pattern was not taking effect at
2044    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2045    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2046    was abstracted outside.
2047    
2048    14. PCRE now supports the \G assertion. It is true when the current matching
2049    position is at the start point of the match. This differs from \A when the
2050    starting offset is non-zero. Used with the /g option of pcretest (or similar
2051    code), it works in the same way as it does for Perl's /g option. If all
2052    alternatives of a regex begin with \G, the expression is anchored to the start
2053    match position, and the "anchored" flag is set in the compiled expression.
2054    
2055    15. Some bugs concerning the handling of certain option changes within patterns
2056    have been fixed. These applied to options other than (?ims). For example,
2057    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2058    been the other way round. Some of this was related to change 7 above.
2059    
2060    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2061    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2062    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2063    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2064    
2065    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2066    mode. Unlike ".", it always matches newline, whatever the setting of
2067    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2068    assertions. Perl allows it, but it doesn't (in general) work because it can't
2069    calculate the length of the lookbehind. At least, that's the case for Perl
2070    5.8.0 - I've been told they are going to document that it doesn't work in
2071    future.
2072    
2073    18. Added an error diagnosis for escapes that PCRE does not support: these are
2074    \L, \l, \N, \P, \p, \U, \u, and \X.
2075    
2076    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2077    reading past the end of the pattern in cases such as /[abcd/.
2078    
2079    20. PCRE was getting more memory than necessary for patterns with classes that
2080    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2081    
2082    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2083    compiling PCRE for use with Virtual Pascal.
2084    
2085    22. Small fix to the Makefile to make it work properly if the build is done
2086    outside the source tree.
2087    
2088    23. Added a new extension: a condition to go with recursion. If a conditional
2089    subpattern starts with (?(R) the "true" branch is used if recursion has
2090    happened, whereas the "false" branch is used only at the top level.
2091    
2092    24. When there was a very long string of literal characters (over 255 bytes
2093    without UTF support, over 250 bytes with UTF support), the computation of how
2094    much memory was required could be incorrect, leading to segfaults or other
2095    strange effects.
2096    
2097    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2098    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2099    there was a subsequent back reference to those brackets. This meant that, for
2100    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2101    possible to check for precisely this case. All we can do is abandon the
2102    optimization if .* occurs inside capturing brackets when there are any back
2103    references whatsoever. (See below for a better fix that came later.)
2104    
2105    26. The handling of the optimization for finding the first character of a
2106    non-anchored pattern, and for finding a character that is required later in the
2107    match were failing in some cases. This didn't break the matching; it just
2108    failed to optimize when it could. The way this is done has been re-implemented.
2109    
2110    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2111    
2112    28. Added a new feature that provides some of the functionality that Perl
2113    provides with (?{...}). The facility is termed a "callout". The way it is done
2114    in PCRE is for the caller to provide an optional function, by setting
2115    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2116    global variable. By default it is unset, which disables all calling out. To get
2117    the function called, the regex must include (?C) at appropriate points. This
2118    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2119    This provides a means of identifying different callout points. When PCRE
2120    reaches such a point in the regex, if pcre_callout has been set, the external
2121    function is called. It is provided with data in a structure called
2122    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2123    matching continues; if it returns a non-zero value, the match at the current
2124    point fails. However, backtracking will occur if possible. [This was changed
2125    later and other features added - see item 49 below.]
2126    
2127    29. pcretest is upgraded to test the callout functionality. It provides a
2128    callout function that displays information. By default, it shows the start of
2129    the match and the current position in the text. There are some new data escapes
2130    to vary what happens:
2131    
2132        \C+         in addition, show current contents of captured substrings
2133        \C-         do not supply a callout function
2134        \C!n        return 1 when callout number n is reached
2135        \C!n!m      return 1 when callout number n is reached for the mth time
2136    
2137    30. If pcregrep was called with the -l option and just a single file name, it
2138    output "<stdin>" if a match was found, instead of the file name.
2139    
2140    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2141    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2142    pcre_exec(). This saves a malloc/free per call. The default value of
2143    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2144    when configuring.
2145    
2146    32. The default maximum size of a compiled pattern is 64K. There have been a
2147    few cases of people hitting this limit. The code now uses macros to handle the
2148    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2149    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2150    configuring. Tests 2 and 5 work only with 2-byte links because they output
2151    debugging information about compiled patterns.
2152    
2153    33. Internal code re-arrangements:
2154    
2155    (a) Moved the debugging function for printing out a compiled regex into
2156        its own source file (printint.c) and used #include to pull it into
2157        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2158        separate copies.
2159    
2160    (b) Defined the list of op-code names for debugging as a macro in
2161        internal.h so that it is next to the definition of the opcodes.
2162    
2163    (c) Defined a table of op-code lengths for simpler skipping along compiled
2164        code. This is again a macro in internal.h so that it is next to the
2165        definition of the opcodes.
2166    
2167    34. Added support for recursive calls to individual subpatterns, along the
2168    lines of Robin Houston's patch (but implemented somewhat differently).
2169    
2170    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2171    allow it to read and process whole directories in Win32. This code was
2172    contributed by Lionel Fourquaux; it has not been tested by me.
2173    
2174    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2175    used to name a group. Names consist of alphanumerics and underscores, and must
2176    be unique. Back references use the syntax (?P=name) and recursive calls use
2177    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2178    numbers. The function pcre_fullinfo() can be used after compilation to extract
2179    a name/number map. There are three relevant calls:
2180    
2181      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2182      PCRE_INFO_NAMECOUNT            yields the number of entries
2183      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2184    
2185    The map is a vector of fixed-size entries. The size of each entry depends on
2186    the length of the longest name used. The first two bytes of each entry are the
2187    group number, most significant byte first. There follows the corresponding
2188    name, zero terminated. The names are in alphabetical order.
2189    
2190    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2191    case instead of 255. Making it the same both with and without UTF-8 support
2192    means that the same test output works with both.
2193    
2194    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2195    calling malloc() with a zero argument.
2196    
2197    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2198    optimization. I've improved things by keeping a bitmap of backreferences with
2199    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2200    fact referenced, the optimization can be applied. It is unlikely that a
2201    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2202    the match to follow \n) will appear inside brackets with a number greater than
2203    31, but if it does, any back reference > 31 suppresses the optimization.
2204    
2205    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2206    of disabling numbered capturing parentheses. Any opening parenthesis that is
2207    not followed by ? behaves as if it were followed by ?: but named parentheses
2208    can still be used for capturing (and they will acquire numbers in the usual
2209    way).
2210    
2211    41. Redesigned the return codes from the match() function into yes/no/error so
2212    that errors can be passed back from deep inside the nested calls. A malloc
2213    failure while inside a recursive subpattern call now causes the
2214    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2215    
2216    42. It is now possible to set a limit on the number of times the match()
2217    function is called in a call to pcre_exec(). This facility makes it possible to
2218    limit the amount of recursion and backtracking, though not in a directly
2219    obvious way, because the match() function is used in a number of different
2220    circumstances. The count starts from zero for each position in the subject
2221    string (for non-anchored patterns). The default limit is, for compatibility, a
2222    large number, namely 10 000 000. You can change this in two ways:
2223    
2224    (a) When configuring PCRE before making, you can use --with-match-limit=n
2225        to set a default value for the compiled library.
2226    
2227    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2228        a different value is set. See 45 below.
2229    
2230    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2231    
2232    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2233    of things that can be changed at compile time. The first argument specifies
2234    what is wanted and the second points to where the information is to be placed.
2235    The current list of available information is:
2236    
2237      PCRE_CONFIG_UTF8
2238    
2239    The output is an integer that is set to one if UTF-8 support is available;
2240    otherwise it is set to zero.
2241    
2242      PCRE_CONFIG_NEWLINE
2243    
2244    The output is an integer that it set to the value of the code that is used for
2245    newline. It is either LF (10) or CR (13).
2246    
2247      PCRE_CONFIG_LINK_SIZE
2248    
2249    The output is an integer that contains the number of bytes used for internal
2250    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2251    
2252      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2253    
2254    The output is an integer that contains the threshold above which the POSIX
2255    interface uses malloc() for output vectors. See item 31 above.
2256    
2257      PCRE_CONFIG_MATCH_LIMIT
2258    
2259    The output is an unsigned integer that contains the default limit of the number
2260    of match() calls in a pcre_exec() execution. See 42 above.
2261    
2262    44. pcretest has been upgraded by the addition of the -C option. This causes it
2263    to extract all the available output from the new pcre_config() function, and to
2264    output it. The program then exits immediately.
2265    
2266    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2267    order to support additional features. One way would have been to define
2268    pcre_exec2() (for example) with extra arguments, but this would not have been
2269    extensible, and would also have required all calls to the original function to
2270    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2271    is used for passing in "extra" data from pcre_study().
2272    
2273    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2274    contains the following fields:
2275    
2276      flags         a bitmap indicating which of the following fields are set
2277      study_data    opaque data from pcre_study()
2278      match_limit   a way of specifying a limit on match() calls for a specific
2279                      call to pcre_exec()
2280      callout_data  data for callouts (see 49 below)
2281    
2282    The flag bits are also defined in pcre.h, and are
2283    
2284      PCRE_EXTRA_STUDY_DATA
2285      PCRE_EXTRA_MATCH_LIMIT
2286      PCRE_EXTRA_CALLOUT_DATA
2287    
2288    The pcre_study() function now returns one of these new pcre_extra blocks, with
2289    the actual study data pointed to by the study_data field, and the
2290    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2291    before. That is, this change is entirely upwards-compatible and requires no
2292    change to existing code.
2293    
2294    If you want to pass in additional data to pcre_exec(), you can either place it
2295    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2296    block.
2297    
2298    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2299    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2300    times with different match limits, until it finds the minimum value needed for
2301    pcre_exec() to complete. The value is then output. This can be instructive; for
2302    most simple matches the number is quite small, but for pathological cases it
2303    gets very large very quickly.
2304    
2305    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2306    returns the size of the data block pointed to by the study_data field in a
2307    pcre_extra block, that is, the value that was passed as the argument to
2308    pcre_malloc() when PCRE was getting memory in which to place the information
2309    created by pcre_study(). The fourth argument should point to a size_t variable.
2310    pcretest has been extended so that this information is shown after a successful
2311    pcre_study() call when information about the compiled regex is being displayed.
2312    
2313    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2314    because what follows is always an absolute path. (Later: it turns out that this
2315    is more than cosmetic for MinGW, because it doesn't like empty path
2316    components.)
2317    
2318    49. Some changes have been made to the callout feature (see 28 above):
2319    
2320    (i)  A callout function now has three choices for what it returns:
2321    
2322           0  =>  success, carry on matching
2323         > 0  =>  failure at this point, but backtrack if possible
2324         < 0  =>  serious error, return this value from pcre_exec()
2325    
2326         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2327         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2328         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2329         use by callout functions. It will never be used by PCRE itself.
2330    
2331    (ii) The pcre_extra structure (see 45 above) has a void * field called
2332         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2333         pcre_callout_block structure has a field of the same name. The contents of
2334         the field passed in the pcre_extra structure are passed to the callout
2335         function in the corresponding field in the callout block. This makes it
2336         easier to use the same callout-containing regex from multiple threads. For
2337         testing, the pcretest program has a new data escape
2338    
2339           \C*n        pass the number n (may be negative) as callout_data
2340    
2341         If the callout function in pcretest receives a non-zero value as
2342         callout_data, it returns that value.
2343    
2344    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2345    there were some redundant $(CFLAGS) in commands that are now specified as
2346    $(LINK), which already includes $(CFLAGS).
2347    
2348    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2349    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2350    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2351    one-byte characters throughout. Note that case-insensitive matching applies
2352    only to characters whose values are less than 256. PCRE doesn't support the
2353    notion of cases for higher-valued characters.
2354    
2355    (i)   A character class whose characters are all within 0-255 is handled as
2356          a bit map, and the map is inverted for negative classes. Previously, a
2357          character > 255 always failed to match such a class; however it should
2358          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2359    
2360    (ii)  A negated character class with a single character < 255 is coded as
2361          "not this character" (OP_NOT). This wasn't working properly when the test
2362          character was multibyte, either singly or repeated.
2363    
2364    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2365          mode, for example: \x{100}{2,3}.
2366    
2367    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2368          singly or repeated) now correctly test multibyte characters. However,
2369          PCRE doesn't recognize any characters with values greater than 255 as
2370          digits, spaces, or word characters. Such characters always match \D, \S,
2371          and \W, and never match \d, \s, or \w.
2372    
2373    (v)   Classes may now contain characters and character ranges with values
2374          greater than 255. For example: [ab\x{100}-\x{400}].
2375    
2376    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2377          PCRE in UTF-8 mode.
2378    
2379    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2380    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2381    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2382    value.)
2383    
2384    53. The single man page has become too large. I have therefore split it up into
2385    a number of separate man pages. These also give rise to individual HTML pages;
2386    these are now put in a separate directory, and there is an index.html page that
2387    lists them all. Some hyperlinking between the pages has been installed.
2388    
2389    54. Added convenience functions for handling named capturing parentheses.
2390    
2391    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2392    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2393    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2394    are faulted.
2395    
2396    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2397    calling configure. These values are used when compiling the dftables.c program
2398    which is run to generate the source of the default character tables. They
2399    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2400    you will need to set these values.
2401    
2402    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2403    
2404    
2405    Version 3.9 02-Jan-02
2406    ---------------------
2407    
2408    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2409    
2410    2. If --disable-static was given, the building process failed when trying to
2411    build pcretest and pcregrep. (For some reason it was using libtool to compile
2412    them, which is not right, as they aren't part of the library.)
2413    
2414    
2415    Version 3.8 18-Dec-01
2416    ---------------------
2417    
2418    1. The experimental UTF-8 code was completely screwed up. It was packing the
2419    bytes in the wrong order. How dumb can you get?
2420    
2421    
2422    Version 3.7 29-Oct-01
2423    ---------------------
2424    
2425    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2426    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2427    this didn't happen under Solaris 8, where I normally test things.
2428    
2429    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2430    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2431    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2432    this fix an hour or so after the initial 3.7 release.)
2433    
2434    
2435    Version 3.6 23-Oct-01
2436    ---------------------
2437    
2438    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2439    offsets passed as NULL with zero offset count.
2440    
2441    2. The config.guess and config.sub files had not been updated when I moved to
2442    the latest autoconf.
2443    
2444    
2445    Version 3.5 15-Aug-01
2446    ---------------------
2447    
2448    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2449    had been forgotten.
2450    
2451    2. By using declared but undefined structures, we can avoid using "void"
2452    definitions in pcre.h while keeping the internal definitions of the structures
2453    private.
2454    
2455    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2456    user point of view, this means that both static and shared libraries are built
2457    by default, but this can be individually controlled. More of the work of
2458    handling this static/shared cases is now inside libtool instead of PCRE's make
2459    file.
2460    
2461    4. The pcretest utility is now installed along with pcregrep because it is
2462    useful for users (to test regexs) and by doing this, it automatically gets
2463    relinked by libtool. The documentation has been turned into a man page, so
2464    there are now .1, .txt, and .html versions in /doc.
2465    
2466    5. Upgrades to pcregrep:
2467       (i)   Added long-form option names like gnu grep.
2468       (ii)  Added --help to list all options with an explanatory phrase.
2469       (iii) Added -r, --recursive to recurse into sub-directories.
2470       (iv)  Added -f, --file to read patterns from a file.
2471    
2472    6. pcre_exec() was referring to its "code" argument before testing that
2473    argument for NULL (and giving an error if it was NULL).
2474    
2475    7. Upgraded Makefile.in to allow for compiling in a different directory from
2476    the source directory.
2477    
2478    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2479    options bits, the pointer it was passed was to an int instead of to an unsigned
2480    long int. This mattered only on 64-bit systems.
2481    
2482    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2483    generated) instead of pcre.in, which it its source. Also made the same change
2484    in several of the .c files.
2485    
2486    10. A new release of gcc defines printf() as a macro, which broke pcretest
2487    because it had an ifdef in the middle of a string argument for printf(). Fixed
2488    by using separate calls to printf().
2489    
2490    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2491    script, to force use of CR or LF instead of \n in the source. On non-Unix
2492    systems, the value can be set in config.h.
2493    
2494    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2495    absolute limit. Changed the text of the error message to make this clear, and
2496    likewise updated the man page.
2497    
2498    13. The limit of 99 on the number of capturing subpatterns has been removed.
2499    The new limit is 65535, which I hope will not be a "real" limit.
2500    
2501    
2502    Version 3.4 22-Aug-00
2503    ---------------------
2504    
2505    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2506    
2507    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2508    
2509    
2510    Version 3.3 01-Aug-00
2511    ---------------------
2512    
2513    1. If an octal character was given, but the value was greater than \377, it
2514    was not getting masked to the least significant bits, as documented. This could
2515    lead to crashes in some systems.
2516    
2517    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2518    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2519    
2520    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2521    These just pass their arguments on to (pcre_free)(), but they are provided
2522    because some uses of PCRE bind it to non-C systems that can call its functions,
2523    but cannot call free() or pcre_free() directly.
2524    
2525    4. Add "make test" as a synonym for "make check". Corrected some comments in
2526    the Makefile.
2527    
2528    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2529    Makefile.
2530    
2531    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2532    command called pgrep for grepping around the active processes.
2533    
2534    7. Added the beginnings of support for UTF-8 character strings.
2535    
2536    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2537    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2538    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2539    out for the ar command.)
2540    
2541    
2542    Version 3.2 12-May-00
2543    ---------------------
2544    
2545    This is purely a bug fixing release.
2546    
2547    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2548    of ZA. This was just one example of several cases that could provoke this bug,
2549    which was introduced by change 9 of version 2.00. The code for breaking
2550    infinite loops after an iteration that matches an empty string was't working
2551    correctly.
2552    
2553    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2554    when matched against abbab (for example). After matching an empty string, it
2555    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2556    caused it to match further down the string than it should.
2557    
2558    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2559    was there because it doesn't seem to be needed, and it causes trouble on some
2560    systems, as it is not a Standard C header. It has been removed.
2561    
2562    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2563    were reported on the Macintosh. The changes were from
2564    
2565      while ((c = *(++ptr)) != 0 && c != '\n');
2566    to
2567      while ((c = *(++ptr)) != 0 && c != '\n') ;
2568    
2569    Totally extraordinary, but if that's what it takes...
2570    
2571    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2572    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2573    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2574    assumes the way PCRE uses memmove() (always moving upwards).
2575    
2576    6. PCRE is being used in one environment where strchr() is not available. There
2577    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2578    faster code anyway.
2579    
2580    
2581    Version 3.1 09-Feb-00
2582    ---------------------
2583    
2584    The only change in this release is the fixing of some bugs in Makefile.in for
2585    the "install" target:
2586    
2587    (1) It was failing to install pcreposix.h.
2588    
2589    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2590    
2591    
2592    Version 3.0 01-Feb-00
2593    ---------------------
2594    
2595    1. Add support for the /+ modifier to perltest (to output $` like it does in
2596    pcretest).
2597    
2598    2. Add support for the /g modifier to perltest.
2599    
2600    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2601    matches null strings.
2602    
2603    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2604    pattern. Perl treats empty patterns specially - it reuses the most recent
2605    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2606    effect.
2607    
2608    5. The POSIX interface was broken in that it was just handing over the POSIX
2609    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2610    required a bigger vector, with some working space on the end. This means that
2611    the POSIX wrapper now has to get and free some memory, and copy the results.
2612    
2613    6. Added some simple autoconf support, placing the test data and the
2614    documentation in separate directories, re-organizing some of the
2615    information files, and making it build pcre-config (a GNU standard). Also added
2616    libtool support for building PCRE as a shared library, which is now the
2617    default.
2618    
2619    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2620    09 are not valid octal constants. Single digits will be used for minor values
2621    less than 10.
2622    
2623    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2624    existing programs that set these in the POSIX interface can use PCRE without
2625    modification.
2626    
2627    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2628    return all that pcre_info() returns, plus additional data. The pcre_info()
2629    function is retained for compatibility, but is considered to be obsolete.
2630    
2631    10. Added experimental recursion feature (?R) to handle one common case that
2632    Perl 5.6 will be able to do with (?p{...}).
2633    
2634    11. Added support for POSIX character classes like [:alpha:], which Perl is
2635    adopting.
2636    
2637    
2638    Version 2.08 31-Aug-99
2639    ----------------------
2640    
2641    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2642    trying to match at the startoffset position, but instead was moving forward to
2643    the next newline as if a previous match had failed.
2644    
2645    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2646    and could get into a loop if a null string was matched other than at the start
2647    of the subject.
2648    
2649    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2650    be distinguished at compile time, and for completeness also added PCRE_DATE.
2651    
2652    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2653    in GnuWin32 environments.
2654    
2655    
2656  Version 2.07 29-Jul-99  Version 2.07 29-Jul-99
2657  ----------------------  ----------------------

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